mc.c

/*
 * mc is capable of compiling a (subset of) C source files into GNU/Linux
 * executables or running via just-in-time compilation on 32-bit ARM
 * processor-based platforms. There is no preprocessor.
 *
 * The following options are supported:
 *   -s : Print source and generated intermediate representation (IR).
 *   -o : Create executable file and terminate normally.
 *
 * If -o and -s are omitted, the compiled code is executed immediately (if
 * there were no compile errors) with the command line arguments passed
 * after the source file parameter.
 *
 * All modifications as of Feb 19 2022 are by HPCguy.
 * See AMaCC project repository for baseline code prior to that date.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <sys/mman.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dlfcn.h>

#define SMALL_TBL_SZ 256

#ifdef __MC__
float strtof(char *s, char **e);
#endif

#ifdef SQUINT_SO
void squint_opt(int *begin, int *end);
#endif

char *freep, *p, *lp; // current position in source code
char *freedata, *data, *_data;   // data/bss pointer

int *e, *le, *text; // current position in emitted IR code
int *lastLEV;       // needed to close out functions
char *idn, *idp;    // decouples ids from program source code
char *idl, *idln;   // storage for func scope label names
int *cas;           // case statement patch-up pointer
int *def;           // default statement patch-up pointer
int *brks;          // break statement patch-up pointer
int *cnts;          // continue statement patch-up pointer
int *rets;          // single function exit model
int  swtc;          // !0 -> in a switch-stmt context
int  brkc;          // !0 -> in a break-stmt context
int  cntc;          // !0 -> in a continue-stmt context
int *tsize;         // array (indexed by type) of type sizes
int tnew;           // next available type
int tk;             // current token
int sbegin;         // statement begin state.
int deadzone;       // don't do inlining during dead code elimination
int attq;           // attribute query such as dereference or sizeof
int parg;           // attq -- assume passing deref var to func means it is set
int inDecl;         // declaration statement context
int pinlndef;       // parsing an inline-only function
int tokloc;         // 0 = global scope, 1 = function scope
                    // 2 = function scope, declaration in progress
union conv {
   int i;
   float f;
} tkv;              // current token value
int ty;             // current expression type
                    // bit 0:1 - tensor rank, eg a[4][4][4]
                    // 0=scalar, 1=1d, 2=2d, 3=3d
                    //   1d etype -- bit 0:30)
                    //   2d etype -- bit 0:15,16:30 [32768,65536]
                    //   3d etype -- bit 0:10,11:20,21:30 [1024,1024,2048]
                    // bit 2:9 - type
                    // bit 10:11 - ptr level
int compound;       // manage precedence of compound assign expressions
int rtf, rtt;       // return flag and return type for current function
int ld, maxld;      // function frame ptr -- argument index then local var
int loc;            // separating point for arg vs local variables
int line;           // current line number
int src;            // print source and assembly flag
int signed_char;    // use `signed char` for `char`
int single_exit;    // one function exit point at end
int elf;            // print ELF format
int peephole;       // helper for peephole optimization
int *n;             // current position in emitted abstract syntax tree
                    // With an AST, the compiler is not limited to generate
                    // code on the fly with parsing.
                    // This capability allows function parameter code to be
                    // emitted and pushed on the stack in the proper
                    // right-to-left order.
int lds[32], ldn;   // used to track scope level for duplicate local var defs
int pplev, pplevt;  // preprocessor conditional level
int ppactive;
int oline, osize;   // for optimization suggestion
char *oname;
int btrue = 0;      // comparison "true" = ( btrue ? -1 : 1)
int ma = 1;         // prevent "modify argument" in functions

// max recursive inline levels
#define INL_LEV 32

// max function arguments
#define MAX_FARG  52

// keywords and global ids grow upward in memory
// Function parameters and (nested) local id scopes grow downward
// When a local block scope terminates, it relinquishes stack space
// Carefully creating declarations with block scopes improves optimization
#define MAX_LABEL 16384
struct ident_s {
   int tk;       // type-id or keyword
   int hash;
   char *name;   // name of this identifier
   char *tsub;   // != 0 substitutes var usage with tsub text, or func
   int class;    // FUNC, GLO (global var), LOC (local var), Syscall
   int type;     // data type such as char and int
   int val;      // usually, contains stack or memory address of var
   int etype;    // extended type info for tensors
   int ftype[2]; // extended type info for funcs
   int flags;    // funcID: 1 = fwd decl func, 2 = func not dead code
                 // varID: 4 = decl initalizer, 8 = assign
                 //        16 = alias initializer, 32 = var was read
                 // retlabel IDs: holds depth of recursive inlining
   int *chain;   // used for forward declaration IR inst ptr
} *id,           // currently parsed identifier
  *sym,          // symbol table (simple list of identifiers)
  *symk,         // tail for keywords
  *symgt,        // tail for global symbols
  *syms,         // struct/union member parsing
  *symlh,        // head for local symbols
  *symlt,        // tail for local symbols
  *labt,         // tail ptr for label Ids
  *retlabel[INL_LEV], // label for end of inline function
  lab[MAX_LABEL];

int mns;            // member namespace -- 1 = member lookup in progress
int masgn;          // This variable is used to skip struct substitutions
int irl;            // inline label counter
char *pts[INL_LEV]; // != 0 means text substitutuion in progress
int tsline[INL_LEV]; // what line is being parsed
int numpts;         // number of text substitution levels in flight
int numfspec;       // number of inlinable functions
int *fspec[256];    // inline function specifications
char linespec[96];  // a string used to capture inlining context

// IR information for local vars and parameters
#define MAX_IR   256
struct ir_s {
  int loc;
  char *name;
} ir_var[MAX_IR];
int ir_count;

// (library) external functions
struct ef_s {
   char *name;
   int addr;
} **ef_cache;
int ef_count;

struct member_s {
   struct member_s *next;
   int hash;
   char *id;
   int offset;
   int type;
   int etype;
} **members; // array (indexed by type) of struct member lists

// tokens and classes (operators last and in precedence order)
// ( >= 128 so not to collide with ASCII-valued tokens)
enum {
   Func=128, Syscall, Main, ClearCache, Fneg, Fabs, Sqrt,
   Glo, Par, Loc, Keyword, Id, Load,
   Enter, Num, NumF, TypeId,
   Typedef, Enum, Char, Int, Float, Struct, Union,
   Sizeof, Return, Goto,
   Break, Continue, If, DoWhile, While, For,
   Switch, Case, Default, Else, Inln, Label,
   Alias, // operator :=, text substitution for simple memory address
   Assign, // operator =, keep Assign as highest priority operator
   OrAssign, XorAssign, AndAssign, ShlAssign, ShrAssign, // |=, ^=, &=, <<=, >>=
   AddAssign, SubAssign, MulAssign, DivAssign, ModAssign, // +=, -=, *=, /=, %=
   Cond, // operator: ?
   Lor, Lan, Or, Xor, And,         // operator: ||, &&, |, ^, &
   Eq, Ne, Ge, Lt, Gt, Le,         // operator: ==, !=, >=, <, >, <=
   Shl, Shr, Add, Sub, Mul, Div, Mod, // operator: <<, >>, +, -, *, /, %
   AddF, SubF, MulF, DivF,       // float type operators (hidden)
   EqF, NeF, GeF, LtF, GtF, LeF,
   CastF, Inc, Dec, Dot, Arrow, Bracket, // operator: ++, --, ., ->, [
   Phf // inform peephole optimizer a function call is beginning
};

// opcodes
/* The instruction set is designed for building intermediate representation.
 * Expression 10 + 20 will be translated into the following instructions:
 *    i = 0;
 *    text[i++] = IMM;
 *    text[i++] = 10;
 *    text[i++] = PSH;
 *    text[i++] = IMM;
 *    text[i++] = 20;
 *    text[i++] = ADD;
 *    text[i++] = PSH;
 *    text[i++] = EXIT;
 *    pc = text;
 */
enum {
   LEA , /*  0 */
   /* LEA addressed the problem how to fetch arguments inside sub-function.
    * Let's check out what a calling frame looks like before learning how
    * to fetch arguments (Note that arguments are pushed in its calling
    * order):
    *
    *     sub_function(arg1, arg2, arg3);
    *
    *     |    ....       | high address
    *     +---------------+
    *     | arg: 1        |    new_bp + 4
    *     +---------------+
    *     | arg: 2        |    new_bp + 3
    *     +---------------+
    *     | arg: 3        |    new_bp + 2
    *     +---------------+
    *     |return address |    new_bp + 1
    *     +---------------+
    *     | old BP        | <- new BP
    *     +---------------+
    *     | local var 1   |    new_bp - 1
    *     +---------------+
    *     | local var 2   |    new_bp - 2
    *     +---------------+
    *     |    ....       |  low address
    *
    * If we need to refer to arg1, we need to fetch new_bp + 4, which can not
    * be achieved by restricted ADD instruction. Thus another special
    * instrcution is introduced to do this: LEA <offset>.
    * Together with JSR, ENT, ADJ, LEV, and LEA instruction, we are able to
    * make function calls.
    */

   IMM , /*  1 */
   /* IMM <num> to put immediate <num> into R0 */

   IMMF , /* 2 */
   /* IMM <num> to put immediate <num> into S0 */

   JMP , /*  3 */
   /* JMP <addr> will unconditionally set the value PC register to <addr> */

   JSR , /*  4 */
   /* Jump to address, setting link register for return address */

   BZ  , /*  5 : conditional jump if R0 is zero (jump-if-zero) */
   BNZ , /*  6 : conditional jump if R0 is not zero */

   ENT , /*  7 */
   /* ENT <size> is called when we are about to enter the function call to
    * "make a new calling frame". It will store the current PC value onto
    * the stack, and save some space(<size> bytes) to store the local
    * variables for function.
    */

   ADJ , /*  8 */
   /* ADJ <size> is to adjust the stack, to "remove arguments from frame"
    * The following pseudocode illustrates how ADJ works:
    *     if (op == ADJ) { sp += *pc++; } // add esp, <size>
    */

   LEV , /*  9 */
   /* LEV fetches bookkeeping info to resume previous execution.
    * There is no POP instruction in our design, and the following pseudocode
    * illustrates how LEV works:
    *     if (op == LEV) { sp = bp; bp = (int *) *sp++;
    *                  pc = (int *) *sp++; } // restore call frame and PC
    */

   PSH , /* 10 */
   /* PSH pushes the value in R0 onto the stack */

   PSHF , /* 11 */
   /* PSH pushes the value in R0 onto the stack */

   LC  , /* 12 */
   /* LC loads a character into R0 from a given memory
    * address which is stored in R0 before execution.
    */

   LI  , /* 13 */
   /* LI loads an integer into R0 from a given memory
    * address which is stored in R0 before execution.
    */

   LF  , /* 14 */
   /* LI loads a float into S0 from a given memory
    * address which is stored in R0 before execution.
    */

   SC  , /* 15 */
   /* SC stores the character in R0 into the memory whose
    * address is stored on the top of the stack.
    */

   SI  , /* 16 */
   /* SI stores the integer in R0 into the memory whose
    * address is stored on the top of the stack.
    */

   SF  , /* 17 */
   /* SI stores the float in S0 into the memory whose
    * address is stored on the top of the stack.
    */

   OR  , /* 18 */  XOR , /* 19 */  AND , /* 20 */
   EQ  , /* 21 */  NE  , /* 22 */
   GE  , /* 23 */  LT  , /* 24 */  GT  , /* 25 */ LE  , /* 26 */
   SHL , /* 27 */  SHR , /* 28 */
   ADD , /* 29 */  SUB , /* 30 */  MUL , /* 31 */ DIV , /* 32 */ MOD, /* 33 */
   ADDF, /* 34 */  SUBF, /* 35 */  MULF, /* 36 */ DIVF, /* 37 */
   FTOI, /* 38 */  ITOF, /* 39 */  EQF , /* 40 */ NEF , /* 41 */
   GEF , /* 42 */  LTF , /* 43 */  GTF , /* 44 */ LEF , /* 45 */
   /* arithmetic instructions
    * Each operator has two arguments: the first one is stored on the top
    * of the stack while the second is stored in R0.
    * After the calculation is done, the argument on the stack will be poped
    * off and the result will be stored in R0.
    */

   FNEG, /* 46 float fnegf(float); returns -arg */
   FABS, /* 47 float fabsf(float); */
   SQRT, /* 48 float sqrtf(float); */
   SYSC, /* 49 system call */
   CLCA, /* 50 clear cache, used by JIT compilation */

   VENT, /* 51 Needed fo Varargs ABI, which requires 8-byte stack align */
   VLEV, /* 52 */

   PHD,  /* 53 PeepHole Disable next assembly instruction in optimizer */
   PHF,  /* 54 Inform peephole optimizer a function call is beginning */
   PHR0, /* 55 Inform PeepHole optimizer that R0 holds a return value */

   INVALID
};

// types -- 4 scalar types, 1020 aggregate types, 4 tensor ranks, 8 ptr levels
// bits 0-1 = tensor rank, 2-11 = type id, 12-14 = ptr level
// 4 type ids are scalars: 0 = char/void, 1 = int, 2 = float, 3 = reserved
enum { CHAR = 0, INT = 4, FLOAT = 8, ATOM_TYPE = 11,
       PTR = 0x1000, PTR2 = 0x2000 };

// ELF generation
char **plt_func_addr;
char *freebuf;

char *append_strtab(char **strtab, char *str)
{
   char *s;
   for (s = str; *s && (*s != ' '); ++s) ; /* ignore trailing space */
   int nbytes = s - str + 1;
   char *res = *strtab;
   memcpy(res, str, nbytes);
   res[s - str] = 0; // null terminator
   *strtab = res + nbytes;
   return res;
}

// need this complex function to trace inlining errors
char *linestr()
{
   char *out = linespec;
   int i, ntmp, tidx=0;
   char stmp[10];
   tsline[numpts] = line;
   if (numpts) { strcpy(linespec, "inline:"); out += 7; }
   for (i=0; i<=numpts; ++i) {
      ntmp = tsline[i];
      while (ntmp>0) { stmp[tidx++] = '0' + ntmp%10; ntmp /= 10; }
      while (tidx > 0) *out++ = stmp[--tidx];
      *out++ = ':';
   }
   *--out = 0;
   if (out == linespec) { *out++ = '0'; *out = 0; }
   return linespec;
}

void fatal(char *msg)
{
   if (!numpts) printf("%d: %.*s\n", line, p - lp, lp);
   printf("%s: %s\n", linestr(), msg); exit(-1);
}

void ef_add(char *name, int addr) // add external function
{
   ef_cache[ef_count] = (struct ef_s *) malloc(sizeof(struct ef_s)) ;
   ef_cache[ef_count]->name = (char *) malloc(strlen(name)+1);
   strcpy(ef_cache[ef_count]->name, name);
   ef_cache[ef_count]->addr = addr;
   ++ef_count;
}

int ef_getaddr(int idx) // get address external function
{
   return (elf ? (int) plt_func_addr[idx] : ef_cache[idx]->addr);
}

int ef_getidx(char *name) // get cache index of external function
{
   int i;
   for (i = 0; i < ef_count; ++i)
      if (!strcmp(ef_cache[i]->name, name))
         break;

   if (i == ef_count) { // add new external lib func to cache
      int dladdr;
      if ((dladdr = (int) dlsym(0, name))) {
         ef_add(name, dladdr);
      } else {
         void *divmod_handle = (void *) dlopen("libgcc_s.so.1", 1);
         if (!divmod_handle) fatal("failed to open libgcc_s.so.1");
         dladdr = (int) dlsym(divmod_handle, name);
         if (!dladdr) // fatal("bad function call");
         {
            void *libm_handle = (void *) dlopen("libm.so.6", 1);
            if (!libm_handle) fatal("failed to open libm.so.6");
            dladdr = (int) dlsym(libm_handle, name);
            if (!dladdr) fatal("bad function call");
         }
         ef_add(name, dladdr);
      }
   }
   return i;
}

inline void expr(int lev);

/* parse next token
 * 1. store data into id and then set the id to current lexcial form
 * 2. set tk to appropriate type
 */
void eol2semi(char *ss) // preprocessor support
{
   char *s;
   s = ss;
   while(*s && *s != '\n') ++s;
   if (*s) *s = ';';
}

void next()
{
   char *pp;
   int t;

   /* using loop to ignore whitespace characters, but characters that
    * cannot be recognized by the lexical analyzer are considered blank
    * characters, such as '@'.
    */
text_sub:
   while ((tk = *p)) {
      ++p;
      if ((tk >= 'a' && tk <= 'z') || (tk >= 'A' && tk <= 'Z') ||
          (tk == '_') || (tk == '$')) {
         pp = p - 1;
         while ((*p >= 'a' && *p <= 'z') || (*p >= 'A' && *p <= 'Z') ||
                (*p >= '0' && *p <= '9') || (*p == '_') || (*p == '$'))
            tk = tk * 147 + *p++;
         tk = (tk << 6) + (p - pp);  // hash plus symbol length
         // hash value is used for fast comparison. Since it is inaccurate,
         // we have to validate the memory content as well.
         int nlen = p - pp;

         for (id = sym; id < symk; ++id) { // check for keywords
            if (tk == id->hash && id->name[nlen] == 0 &&
                !memcmp(id->name, pp, nlen)) {
               tk = id->tk;
               return;
            }
         }
         if (tokloc) {
            for (id = symlh; id < symlt; ++id) { // local ids
               if (tk == id->hash && id->name[nlen] == 0 &&
                   !memcmp(id->name, pp, nlen)) {
                  if (tokloc == 2) {
                     if (id->val > lds[ldn])
                        fatal("redefinition of var within scope");
                     else {
                        printf("%s: var %s decl hides previous decl\n",
                               linestr(), id->name);
                        goto new_block_def;
                     }
                  }
                  if (id->tsub && !mns) {
                     if (id->val & 1) { // recursive
                        // handle recursion
                        if (id->val == 3) { id->val = 1; continue; }
                        else id->val = 3;
                     }
                     if (numpts == INL_LEV) fatal("inline level exceeded");
                     tsline[numpts] = 0;
                     pts[numpts++] = p; p = id->tsub;
                     goto text_sub;
                  }
                  tk = id->tk;
                  return;
               }
            }
         }
         if (tokloc < 2) {
            for (id = symk; id < symgt; ++id) { // global ids
               if (tk == id->hash && id->name[nlen] == 0 &&
                   !memcmp(id->name, pp, nlen)) {
                  tk = id->tk;
                  return;
               }
            }
         }
         if (tokloc) {
            for (id = lab; id < labt; ++id) { // labels
               if (tk == id->hash && id->name[nlen] == 0 &&
                   !memcmp(id->name, pp, nlen)) {
                  tk = id->tk;
                  return;
               }
            }
         }
         // At this point, pre-existing symbol name was not found.
new_block_def:
         id = tokloc ? --symlh : symgt++;
         id->name = idp;
         memcpy(idp, pp, nlen); idp[nlen] = 0;
         idp = (char *) (((int) idp + nlen + 1 + sizeof(int)) &
                         (-sizeof(int)));
         id->hash = tk;
         tk = id->tk = Id;  // token type identifier
         id->class = id->val = id->type = id->etype = 0;
         id->tsub = 0;
         id->flags = 0;
         id->chain = 0;
         return;
      }
      /* Calculate the constant */
      // first byte is a digit, and it is considered a numerical value
      else if (tk >= '0' && tk <= '9') {
         tk = Num; // token is char or int
         tkv.i = strtoul((pp = p - 1), &p, 0); // octal, decimal, hex parsing
         if (*p == '.') { // float
            tkv.f = strtof(pp, &p); tk = NumF;
            if (*p == 'f') ++p; // floating const has 'f' suffix
         }
         return;
      }
      switch (tk) {
      case '\n':
         if (lp < p && !numpts) {
            if (src) printf("%d: %.*s", line, p - lp, lp);
            lp = p;
         }
         ++line;
      case ' ':
      case '\t':
      case '\v':
      case '\f':
      case '\r':
         break;
      case '/':
         if (*p == '/') { // comment
            while (*p != 0 && *p != '\n') ++p;
         } else if (*p == '*') { // C-style multiline comments
            t = 0;
            for (++p; (*p != 0) && (t == 0); ++p) {
               pp = p + 1;
               if (*p == '\n') ++line;
               else if (*p == '*' && *pp == '/') t = 1;
            }
            ++p;
         } else {
            if (*p == '=') { ++p; tk = DivAssign; }
            else tk = Div; return;
         }
         break;
      case '#': // skip include statements, and most preprocessor directives
         if (!strncmp(p, "define", 6)) {
            p += 6; next(); if (!ppactive) break;
            if (tk == Id) {
               struct ident_s *ndd = id;
               int *nbase = n;
               if (ndd->class != 0) fatal("can't redefine preprocessor symbol");
               while (*p == ' ') ++p;
               if (*p == '\n') {    // no value assigned
                  ndd->class = Num; ndd->type = INT;
                  break;
               }
               eol2semi(p); next(); expr(Cond); *--p = '\n';
               if ((nbase - n) == 2 && (*n == Num || *n == NumF)) {
                  ndd->class = *n; ndd->val = n[1];
                  ndd->type = (*n == Num) ? INT : FLOAT;
                  n += 2; // remove expr from AST
                  break;
               }
               else
                  fatal("Bad #define syntax");
            }
            else {
               fatal("Bad #define syntax");
            }
         }
         else if ((t = !strncmp(p, "ifdef", 5)) || !strncmp(p, "ifndef", 6)) {
            p += 6; next();
            if (tk != Id) fatal("No identifier");
            ++pplev;
            if (ppactive &&
               (((id->class == Num || id->class == NumF) ^ t) & 1)) {
               int *nbase = n; ppactive = 0;
               t = pplevt; pplevt = pplev - 1;
               do next(); while (pplev != pplevt);
               pplevt = t;
               n = nbase; ppactive = 1;
            }
         }
         else if (!strncmp(p, "if", 2)) {
            int *nbase = n;
            p += 2;
            ++pplev;
            if (!ppactive) break;
            eol2semi(p); next(); expr(Cond); *--p = '\n';
            if ((nbase - n) == 2 && (*n == Num || *n == NumF)) {
               t = n[1]; n += 2;
               if (t == 0) { // throw away code inside of #if
                  t = pplevt; pplevt = pplev - 1; ppactive = 0;
                  do next(); while (pplev != pplevt);
                  pplevt = t;
                  n = nbase; ppactive = 1;
               }
            }
            else
               fatal("#if expression does not evaluate to const value");
         }
         else if(!strncmp(p, "endif", 5)) {
            p += 5;
            if (--pplev < 0) fatal("preprocessor context nesting error");
            if (pplev == pplevt) return;
         }
         else if (!strncmp(p, "else", 4) || !strncmp(p, "elif", 4)) {
            p += 4;
            if (ppactive) fatal("#else/elif not supported in preprocessor");
         }
         else if (!strncmp(p, "error", 5)) {
            p += 5;
            if (ppactive) fatal ("#error encountered");
         }
         else {
            while (*p && *p != '\n') ++p;
         }
         break;
      case '\'': // quotes start with character (string)
      case '"':
         pp = data;
         while (*p != 0 && *p != tk) {
            if ((tkv.i = *p++) == '\\') {
               switch (tkv.i = *p++) {
               case 'n': tkv.i = '\n'; break; // new line
               case 't': tkv.i = '\t'; break; // horizontal tab
               case 'v': tkv.i = '\v'; break; // vertical tab
               case 'f': tkv.i = '\f'; break; // form feed
               case 'r': tkv.i = '\r'; break; // carriage return
               case '0': tkv.i = '\0'; break; // an int with value 0
               }
            }
            // if it is double quotes (string literal), it is considered as
            // a string, copying characters to data
            if (tk == '"') *data++ = tkv.i;
         }
         ++p;
         if (tk == '"') tkv.i = (int) pp; else tk = Num;
         return;
      case '=': if (*p == '=') { ++p; tk = Eq; } else tk = Assign; return;
      case '*': if (*p == '=') { ++p; tk = MulAssign; }
                else tk = Mul; return;
      case '+': if (*p == '+') { ++p; tk = Inc; }
                else if (*p == '=') { ++p; tk = AddAssign; }
                else tk = Add; return;
      case '-': if (*p == '-') { ++p; tk = Dec; }
                else if (*p == '>') { ++p; tk = Arrow; }
                else if (*p == '=') { ++p; tk = SubAssign; }
                else tk = Sub; return;
      case '[': tk = Bracket; return;
      case '&': if (*p == '&') { ++p; tk = Lan; }
                else if (*p == '=') { ++p; tk = AndAssign; }
                else tk = And; return;
      case '!': if (*p == '=') { ++p; tk = Ne; } return;
      case '<': if (*p == '=') { ++p; tk = Le; }
                else if (*p == '<') {
                   ++p; if (*p == '=') { ++p ; tk = ShlAssign; } else tk = Shl;
                }
                else tk = Lt; return;
      case '>': if (*p == '=') { ++p; tk = Ge; }
                else if (*p == '>') {
                   ++p; if (*p == '=') { ++p ; tk = ShrAssign; } else tk = Shr;
                }
                else tk = Gt; return;
      case '|': if (*p == '|') { ++p; tk = Lor; }
                else if (*p == '=') { ++p; tk = OrAssign; }
                else tk = Or; return;
      case '^': if (*p == '=') { ++p; tk = XorAssign; } else tk = Xor; return;
      case '%': if (*p == '=') { ++p; tk = ModAssign; }
                else tk = Mod; return;
      case '?': tk = Cond; return;
      case '.': tk = Dot; return;
      case ':': if (*p == '=') { ++p; tk = Alias; } return;
      default: return;
      }
   }

   if (numpts != 0) {
      p = pts[--numpts];
      if (tsline[numpts] != 0) line = tsline[numpts];
      goto text_sub;
   }
}

int popcount32(int ii)
{
   int i;
   i = ii - ((ii >> 1) & 0x55555555); // add pairs of bits
   i = (i & 0x33333333) + ((i >> 2) & 0x33333333); // quads
   i = (i + (i >> 4)) & 0x0F0F0F0F; // groups of 8
   return (i * 0x01010101) >> 24; // horizontal sum of bytes
}

// verify binary operations are legal
void typecheck(int op, int tl, int tr)
{
   int pt = 0, it = 0, st = 0;
   if (tl >= PTR)  pt += 2; // is pointer?
   if (tr >= PTR)  pt += 1;

   if (tl < FLOAT) it += 2; // is int?
   if (tr < FLOAT) it += 1;

   if (tl > ATOM_TYPE && tl < PTR) st += 2; // is struct/union?
   if (tr > ATOM_TYPE && tr < PTR) st += 1;

   if ((tl ^ tr) & (PTR | PTR2)) { // operation on different pointer levels
      if (op == Add && pt != 3 && (it & ~pt)) ; // ptr + int or int + ptr ok
      else if (op == Sub && pt == 2 && it == 1) ; // ptr - int ok
      else if (op == Assign && pt == 2 && *n == Num && n[1] == 0) ; // ok
      else if (op >= Eq && op <= Le && *n == Num && n[1] == 0) ; // ok
      else fatal("bad pointer arithmetic or cast needed");
   }
   else if (pt == 3 && op != Assign && op != Sub &&
            (op < Eq || op > Le)) // pointers to same type
      fatal("bad pointer arithmetic");

   if (pt == 0 && op != Assign && (it == 1 || it == 2))
      fatal("cast operation needed");

   if (pt == 0 && st != 0)
      fatal("illegal operation with dereferenced struct");
}

void bitopcheck(int tl, int tr)
{
   if (tl >= FLOAT || tr >= FLOAT)
      fatal("bit operation on non-int types");
}

int tensor_size(int dim, int etype)
{
   int retVal;
   switch (dim) {
   case 1: retVal = (etype+1);
           break;
   case 2: retVal = ((etype & 0xffff) + 1) * ((etype >> 16) + 1);
           break;
   case 3: retVal = ((etype & 0x7ff) + 1) *
                    (((etype >> 11) & 0x3ff) + 1) *
                    ((etype >> 21) + 1);
           break;
   }
   return retVal;
}

/* expression parsing
 * lev represents an operator.
 * because each operator `token` is arranged in order of priority,
 * large `lev` indicates a high priority.
 *
 * Operator precedence (lower first):
 * Assign  =
 * Cond   ?
 * Lor    ||
 * Lan    &&
 * Or     |
 * Xor    ^
 * And    &
 * Eq     ==
 * Ne     !=
 * Ge     >=
 * Lt     <
 * Gt     >
 * Le     <=
 * Shl    <<
 * Shr    >>
 * Add    +
 * Sub    -
 * Mul    *
 * Div    /
 * Mod    %
 * Inc    ++
 * Dec    --
 * Bracket [
 */

#define REENTRANT 0x10000

inline void stmt(int ctx);

int idchar(int n) // 6 bits wide
{
   int val;
   if (n < 10) val = '0' + n;
   else if (n < 36) val = 'a' + n - 10;
   else if (n < 62) val = 'A' + n - 36;
   else val = ((n == 62) ? '_' : '$');
   return val;
}

/* Drop second item on AST stack */
void swapDrop(int *b, int sz) // n is global
{
   int *t, *c = b, *a = b + sz;
   do {
      --c; --a;
      t = (int *) (*a = *c);
      if (t >= n && t <= b) *a += sz; // sketchy, not guaranteed safe
   } while (c != n);
   n += sz;
}

int elideZero(int *aa, int *b, int bt, int op) // n and ty are global
{
   // 0 = no elision, 1 = const elision, 2 = AST deletion (NOP)
   int elide = 0;
   if ((aa-n) == 2 && *n == Num) {
      if (*b == Num) elide = 1;
      else if (n[1] == 0) { n += 2; ty = bt; elide = 2; }
   }
   else if (aa == b && *b == Num && b[1] == 0) {
      swapDrop(b, 2); elide = 2;
   }

   return elide;
}

int hasSideEffect(int *b, int *e) // conservative, so not strictly sketchy
{
   int *s;
   s = b;
   while (s != e) {
      if (*s == Inc || *s == Dec || *s == Assign) break;
      ++s;
   }
   return (s != e);
}

int idMatch(char *id, char *expr)
{
   int retVal = 0;
   int bracketLev = 0;
   char *a = id, *b = expr;

   while (*a && *a++ == *b++);
   while (*b) {
      if (*b != ' ') {
         if (bracketLev == 0 && *b != '[') break;
         if (*b == '[') ++bracketLev;
         else if (*b == ']') --bracketLev;
      }
      ++b;
   }
   if (*b && *b == ')' && b[1] == 0) retVal = !0;
   return retVal;
}

void modArgCheck(int *node)
{
   if (ma && node[0] == Loc && node[1] > 1)
      fatal("Can't modify passed argument (compile -ma to allow)");
}

void flagWrite(int *flags, int *high, int *low)
{
   *flags |= ((*flags & 4) ? 8 : 4);
   if (high - low == 2 && *low != Num && *low != NumF) *flags |= 64; // not lit
}

void expr(int lev)
{
   int t, tc, tt[2], nf, sz;
   int *a, *b, *c;
   int memsub = 0;
   union conv *c1, *c2;
   struct ident_s *d;
   struct member_s *m;
   int inln_func = 0;

   switch (tk) {
   case Id:
do_inln_func:
      d = id; next();
      if (tokloc && sbegin && tk == ':') {
         if (d->class != 0 || !(d->type == 0 || d->type == -1))
            fatal("invalid label");
         if (d < lab || d >= labt) { // move labels to separate area
            if (d != symlh || (labt - lab) == MAX_LABEL)
               fatal("label problem");
            memcpy(idl, d->name, t = idp - d->name); idp = d->name;
            memcpy(d = labt++, symlh++, sizeof (struct ident_s));
            d->name = idl; idl += t;
         }
         d->type = -1 ; // hack for d->class deficiency
         *--n = (int) d; *--n = Label;
         next(); return;
      }
      sbegin = 0;
      // function call
      if (tk == '(') {
         int fidx, tsi, *saven = 0;
         char *psave, *ts[52];
         if (d == symlh) { // move ext func Ids to global sym table
            memcpy(d = symgt++, symlh++, sizeof (struct ident_s));
         }
         if (d->class == Func && d->val == 0 &&
             d->tsub == 0 && (d->flags & 1) == 0) { // lib func prototype
            goto resolve_fnproto;
         }
         if (d->class < Func || d->class > Sqrt) {
            if (d->class != 0) fatal("bad function call");
            d->type = INT;
            d->ftype[0] = d->ftype[1] = 0;
resolve_fnproto:
            d->class = Syscall;
            d->val = ef_getidx(d->name) ;
            if (inln_func) inln_func = 0; // should I warn here?
            if (d->tsub) fatal("internal compiler error");
         }
         while (*p == ' ' || *p == 0x0a) if (*p++ == 0x0a) ++line;
         psave = p;
         next();
         t = 0; b = c = 0; tt[0] = tt[1] = 0; nf = 0; // FP argument count
         if (!deadzone && (inln_func || d->tsub)) {
            if (d->tsub) {
               if (numpts == INL_LEV) {
                  if (d->val == 0) fatal("inline level exceeded");
               }
               else { fidx = ((int) d->tsub) - 1; inln_func = 1; }
            }
            else {
               for (fidx = 0; fidx < numfspec; ++fidx)
                  if (!strcmp(d->name, (char *)fspec[fidx][0])) break;
            }
            if (fidx == numfspec || numpts == INL_LEV) inln_func = 0; // warn?
            else { tsi = 0; saven = n; }
         }
         if (peephole && (d->class < Fneg || d->class > Sqrt) && !inln_func) {
            *--n = Phf; c = n;
         }
         parg = 1;
         while (tk != ')') {
            if (inln_func && !deadzone) {
               a = n; expr(Assign);
               ts[tsi++] = idp;
               if ((a-n == 2) && (*n == Num || *n == NumF)) { // lit const
                  a = (int *) idp;
                  *a++ = n[0]; *a++ = n[1];
                  idp = (char *) a;
               }
               else {
                  *idp = '(';
                  memcpy(idp+1, psave, p-psave-1);
                  idp[p-psave] = ')'; idp[p-psave+1] = 0;
                  idp = (char *) (((int) idp +
                                   (p - psave) + 2 + sizeof(int)) &
                                  (-sizeof(int)));
               }
               while (*p == ' ' || *p == 0x0a) if (*p++ == 0x0a) ++line;
               psave = p;
            }
            else expr(Assign);
            *--n = (int) b; b = n; ++t;
            if (ty == FLOAT) { ++nf; tt[(t+11)/32] |= 1 << ((t+11) % 32); }
            if (tk == ',') {
               next();
               if (tk == ')') fatal("unexpected comma in function call");
            } else if (tk != ')') fatal("missing comma in function call");
         }
         if (t > MAX_FARG) fatal("maximum of 52 function parameters");
         parg = 0;
         tt[0] += (nf << 6) + t;
         if (d->ftype[0] && (d->ftype[0] != tt[0] || d->ftype[1] != tt[1]) )
            fatal("argument type mismatch");
         if (inln_func && !deadzone) {
            int i, args;
            int old;
            char *s;
            struct ident_s *osymh;
            char *save_tsub = d->tsub;
            d->tsub = (char *) (fidx + 1);

            n = saven; // get rid of pushed function arguments

            // create a label for the end of the inline function
            if ((labt - lab) == MAX_LABEL) fatal("label overflow");
            id = labt++;
            id->name = s = idl;
            id->name[0] = 'i'; id->name[1] = 'r'; id->name[2] = 'l';
            id->name[3] = idchar((irl>>18) & 63);
            id->name[4] = idchar((irl>>12) & 63);
            id->name[5] = idchar((irl>> 6) & 63);
            id->name[6] = idchar(irl       & 63);
            id->name[7] = 0;
            idl += 8;
            ++irl;
            tk = *s++;
            while (*s) tk = tk * 147 + *s++;
            id->hash = (tk << 6) + 7;
            id->type = -1; // hack for id->class deficiency
            id->tk = Id;  // token type identifier
            id->class = id->val = id->etype = 0;
            id->tsub = 0;
            id->flags = 0;
            id->chain = 0;

            // save source code position to return to after function call
            retlabel[numpts] = id;
            tsline[numpts] = line;
            pts[numpts++] = p;

            // point source code at inline function
            p = (char *)fspec[fidx][1]; // func body source
            line = (int) fspec[fidx][2] ; // func body line num

            *--n = ';' ;   // Create block scope in AST, '{'

            // create block scope for local variables
            lds[++ldn] = old = ld; osymh = symlh;

            // create substitution variables
            args = (int) fspec[fidx][3]; // number of params in func def
            for (i = 0; i < args; ++i) {
               int recursive = 0;
               char *tsn = (char *) fspec[fidx][4+i]; // param names
               tk = *tsn++;
               while (*tsn) tk = tk * 147 + *tsn++;
               tk = (tk << 6) + (tsn - (char *)fspec[fidx][4+i]);
               tsn = (char *) fspec[fidx][4+i]; // param names
               if (*ts[i] == '(') { // simple alias (e.g. &x, x, x[n])
                  if (*tsn == ts[i][1] ||
                      (ts[i][1] == '&' && *tsn == ts[i][2])) {
                     int off = (*tsn == ts[i][1]) ? 1 : 2;
                     if (idMatch(tsn, ts[i]+off)) {
                        if (off == 1) continue;
                        else recursive = 1; // off == 2
                     }
                  }
                  id = --symlh ;
                  id->name = tsn; id->hash = tk;
                  tk = id->tk = Id;  // token type identifier
                  id->class = Loc;
                  id->val = recursive; // recursion flags
                  id->type = id->etype = 0;
                  id->tsub = ts[i];
               }
               else { // literal constant
                  id = --symlh ;
                  id->name = tsn; id->hash = tk;
                  tk = id->tk = Id;  // token type identifier
                  a = (int *) ts[i];
                  id->class = a[0]; id->val = a[1];
                  id->type = ((id->class == Num) ? INT : FLOAT);
                  id->etype = 0;
                  id->tsub = 0;
               }
            }

            next(); // get first token from inline function

            while (tk != '}') {
               c = n; stmt(Loc);
               if (c != n) { *--n = (int) c; *--n = '{'; }
            }

            // reduce literal constant expressions
            if ((saven - n) == 9 &&
                (n[6] == Num || n[6] == NumF) &&
                (n[5] == (int) retlabel[numpts-1])) {
               --(retlabel[numpts-1]->flags);
               *--saven = n[7]; *--saven = n[6]; n = saven;
            }
            else if ((saven - n) == 5 &&
                     (n[2] == Num || n[2] == NumF)) {
               *--saven = n[3]; *--saven = n[2]; n = saven;
            }
            else if (n[2] == '{' && n[3] == ((int) (n + 6)) &&
               n[4] == Goto && n[5] == (int) retlabel[numpts-1]) {
               // handle common case of return at end of function
               --(retlabel[numpts-1]->flags);
               n[5] = n[1]; n[4] = n[0]; n += 4;
            }

            if (retlabel[numpts-1]->flags) {
               c = n; *--n = (int) retlabel[numpts-1]; *--n = Label;
               *--n = (int) c;  *--n = '{';
            }

            if (ld > maxld) maxld = ld;
            --ldn; ld = old; symlh = osymh;

            d->tsub = save_tsub;
            ty = d->type;

            p = pts[--numpts];
            line = tsline[numpts];

            next();
         }
         else {
            next();
            // function or system call id
            *--n = tt[1]; *--n = tt[0]; *--n = t;
            *--n = ((d->class == Func) ? ((int) d) : d->val);
            *--n = (int) b; *--n = d->class;
            if (c != 0) { *--n = (int) c; *--n = '{'; c = 0; } // peephole
            ty = d->type;
         }
      }
      // enumeration, only enums have ->class == Num
      else if (d->class == Num || d->class == NumF) {
         *--n = d->val; *--n = d->class; ty = d->type; d->flags |= 32; // read
      }
      else {
         // Variable get offset
         switch (d->class) {
         case Par: d->flags |= 4; // all args are inited -- fall through to Loc
         case Loc: *--n = loc - d->val; *--n = Loc;
            if (attq == 0 && (d->flags & 0x1c) == 0) {
               if ((tk > Assign && tk < Dot) || // arr/struct contents ignrd
                   tk == ';' || tk == ')' || tk == ',' || tk == ']')
                  fatal("var use before assignment");
            }
            break;
         case Glo: *--n = d->val; *--n = Num; d->flags |= 4; break; // 0 dflt
         default: fatal("undefined variable");
         }
         if (tk < Alias || tk > ModAssign) d->flags |= 32; // var is read
         else if (d->flags & 16) fatal("Can't assign to an Alias");
         if ((d->type & 3) && d->class != Par) { // push reference address
            ty = d->type & ~3;
         }
         else {
            *--n = (ty = d->type & ~3); *--n = Load;
         }
      }
      break;
   // directly take an immediate value as the expression value
   // IMM recorded in emit sequence
   case Num : *--n = tkv.i; *--n = Num;  next(); ty = INT; break;
   case NumF: *--n = tkv.i; *--n = NumF; next(); ty = FLOAT; break;
   case '"': // string, as a literal in data segment
      *--n = tkv.i; *--n = Num; next();
      // continuous `"` handles C-style multiline text such as `"abc" "def"`
      while (tk == '"') next();
      data = (char *) (((int) data + sizeof(int)) & (-sizeof(int)));
      ty = CHAR + PTR;
      break;
   /* SIZEOF_expr -> 'sizeof' '(' 'TYPE' ')'
    * FIXME: not support "sizeof (Id)".
    */
   case Sizeof:
      next();
      if (tk != '(') fatal("open parenthesis expected in sizeof");
      attq = 1;
      next(); d = 0; t = 1;
      if (tk == Id || tk == TypeId) {
         d = id; ty = d->type;
         if (ty & 3) t *= tensor_size(ty & 3, d->etype);
         next();
      }
      else {
         ty = INT; // Enum
         switch (tk) {
         case Char:
         case Int:
         case Float:
            ty = (tk - Char) << 2; next(); break;
         case Struct:
         case Union:
            next();
            if (tk != Id || id->type <= ATOM_TYPE || id->type >= PTR)
               fatal("bad struct/union type");
            ty = id->type; next(); break;
         }
         // multi-level pointers, plus `PTR` for each level
         while (tk == Mul) { next(); ty += PTR; }
      }
      if (tk != ')') fatal("close parenthesis expected in sizeof");
      attq = 0;
      next();
      *--n = (ty & 3) ?
             (((ty - PTR) >= PTR) ? sizeof(int) : tsize[(ty - PTR) >> 2]) :
             ((ty >= PTR) ? sizeof(int) : tsize[ty >> 2]); *--n = Num;
      // just one dimension supported at the moment
      if (d != 0 && (ty & 3)) n[1] *= t;
      ty = INT;
      break;
   // Type cast or parenthesis
   case '(':
      next();
      if ((tk >= Char && tk <= Union) || tk == TypeId) {
         switch (tk) {
         case TypeId:
            if (id->type & 3) fatal("can't cast to tensor type... yet");
            else t = id->type;
            next(); break;
         case Char:
         case Int:
         case Float:
            t = (tk - Char) << 2; next(); break;
         default:
            next();
            if (tk != Id || id->type <= ATOM_TYPE || id->type >= PTR)
               fatal("bad struct/union type");
            t = id->type; next(); break;
         }
         // t: pointer
         while (tk == Mul) { next(); t += PTR; }
         if (tk != ')') fatal("bad cast");
         next();
         expr(Inc); // cast has precedence as Inc(++)
         if (t != ty && (t == FLOAT || ty == FLOAT)) {
            if (t == FLOAT && ty < FLOAT) { // int to float
               if (*n == Num) { *n = NumF; c1 = &n[1]; c1->f = (float) c1->i; }
               else { b = n; *--n = ITOF; *--n = (int) b; *--n = CastF; }
            }
            else if (t < FLOAT && ty == FLOAT) { // float to int
               if (*n == NumF) { *n = Num; c1 = &n[1]; c1->i = (int) c1->f; }
               else { b = n; *--n = FTOI; *--n = (int) b; *--n = CastF; }
            }
            else fatal("explicit cast required");
         }
         ty = t;
      } else {
         expr(Assign);
         while (tk == ',') {
            next(); b = n;  expr(Assign);
            if (b != n) { *--n = (int) b; *--n = '{'; }
         }
         if (tk != ')') fatal("close parenthesis expected");
         next();
      }
      break;
   case Mul: // "*", dereferencing the pointer operation
      next();
      expr(Inc); // dereference has the same precedence as Inc(++)
      if (ty < PTR) fatal("bad dereference");
      ty -= PTR; *--n = ty; *--n = Load;
      break;
   case And: // "&", take the address operation
      /* when "token" is a variable, it takes the address first and
       * then LI/LC, so `--e` becomes the address of "a".
       */
      attq = 1; next(); if (tk == Id && parg) id->flags |= (8 | 32 | 64);
      expr(Inc);
      if (*n != Load) fatal("bad address-of");
      attq = 0;
      n += 2;
      ty += PTR;
      break;
   case '!': // "!x" is equivalent to "x == 0"
      next(); expr(Inc);
      if (ty >= FLOAT && ty < PTR) fatal("! operator undefined on type");
      if (*n == Num) n[1] = n[1] ? 0 : (btrue ? -1 : 1);
      else { *--n = 0; *--n = Num; --n; *n = (int) (n + 3); *--n = Eq; }
      ty = INT;
      break;
   case '~': // "~x" is equivalent to "x ^ -1"
      next(); expr(Inc); if (ty >= FLOAT) fatal("~ applied to illegal type");
      if (*n == Num) n[1] = ~n[1];
      else { *--n = -1; *--n = Num; --n; *n = (int) (n + 3); *--n = Xor; }
      ty = INT;
      break;
   case Add:
      next(); expr(Inc); if (ty > ATOM_TYPE) fatal("unary '+' illegal on ptr");
      break;
   case Sub:
      next(); expr(Inc); if (ty > ATOM_TYPE) fatal("unary '-' illegal on ptr");
      if (*n == Num) n[1] = -n[1];
      else if (*n == NumF) { n[1] ^= 0x80000000; }
      else if (ty == FLOAT) {
         *--n = 0; *--n = 0; *--n = 0x1041; *--n = 1;
         *--n = FNEG; --n; *n = (int) (n+5); *--n = Fneg;
      }
      else {
         *--n = -1; *--n = Num; --n; *n = (int) (n + 3); *--n = Mul;
      }
      if (ty != FLOAT) ty = INT;
      break;
   case Inc:
   case Dec: // processing ++x and --x. x-- and x++ is handled later
      t = tk; next(); expr(Inc);
      if (ty == FLOAT) fatal("no ++/-- on float");
      if (*n != Load) fatal("bad lvalue in pre-increment");
      *n = t; modArgCheck(n+2);
      if (n[2] == Loc && (id->flags & 0x0c) == 0)
         fatal("modifying uninitialized variable");
      id->flags |= (8 | 64); // written, not literal constant
      break;
   case Inln:
      next();
      if (!(tk == Id && id->class == Func))
         fatal("inline cast only applies to functions");
      if (!pinlndef) inln_func = 1;
      goto do_inln_func;
      break;
   case 0: fatal("unexpected EOF in expression");
   default:
      if (tk & REENTRANT)
         tk ^= REENTRANT;
      else
         fatal("bad expression");
   }

   // "precedence climbing" or "Top Down Operator Precedence" method
   while (tk >= lev) {
      // tk is ASCII code will not exceed `Num=128`. Its value may be changed
      // during recursion, so back up currently processed expression type
      t = ty; b = n;
      switch (tk) {
      case Assign:
         if (t & 3) fatal("Cannot assign to array type lvalue");
         // the left part is processed by the variable part of `tk=ID`
         // and pushes the address
         if (*n != Load) fatal("bad lvalue in assignment");
         n += 2; b = n; modArgCheck(b);
         a = (*b == Loc || *b == Num) ? &id->flags : (int *) 0; // write
         next(); expr(Assign); typecheck(Assign, t, ty);
         if (a) flagWrite(a, b, n);
         *--n = (int) b; *--n = (ty << 16) | t; *--n = Assign; ty = t;
         break;
      case  OrAssign: // right associated
      case XorAssign:
      case AndAssign:
      case ShlAssign:
      case ShrAssign:
      case AddAssign:
      case SubAssign:
      case MulAssign:
      case DivAssign:
      case ModAssign:
         if (t & 3) fatal("Cannot assign to array type lvalue");
         if (*n != Load) fatal("bad lvalue in assignment");
         d = id; n += 2; b = n; *--n = ';'; *--n = t; *--n = Load;
         if (tk < ShlAssign) tk = Or + (tk - OrAssign);
         else tk = Shl + (tk - ShlAssign);
         tk |= REENTRANT; ty = t; compound = 1; a = n; expr(Assign);
         if (a != n) {
            modArgCheck(b); // maybe sum of lit const should not be lit const?
            if (*b == Loc || *b == Num) flagWrite(&d->flags,a,n); // var write
            *--n = (int) b; *--n = (ty << 16) | t; *--n = Assign; ty = t;
         } // else can't optimize away assign-expr, unlike an assign-stmt
         break;
      case Cond: // `x?a:b` is similar to if except that it relies on else
         t = -1;
         if (*n == Num || *n == NumF) { t = n[1]; n += 2; b = n; }
         else if (ty == FLOAT) {
            *--n = 0; *--n = NumF; --n; *n = (int) (n + 3); *--n = NeF; b = n;
         }
         next(); if (t == 0) { ++pinlndef; ++deadzone; }
         expr(Assign); tc = ty;
         if (t == 0) { --deadzone; --pinlndef; n = b; }
         if (tk != ':') fatal("conditional missing colon");
         next(); c = n; if (t == 1) { ++pinlndef; ++deadzone; }
         expr(Cond);
         if (t == 1) { --deadzone; --pinlndef; n = c; ty = tc; }
         if (t == -1) {
            if (tc != ty) fatal("both results need same type");
            --n; *n = (int) (n + 1); *--n = (int) c;
            *--n = (int) b; *--n = Cond;
         }
         break;
      case Lor: // short circuit, the logical or
         next(); expr(Lan);
         if (*n == Num && *b == Num) {
            b[1] = (b[1] || n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
         }
         else { *--n = (int) b; *--n = Lor; }
         ty = INT;
         break;
      case Lan: // short circuit, logic and
         next(); expr(Or);
         if (*n == Num && *b == Num) {
            b[1] = (b[1] && n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
         }
         else { *--n = (int) b; *--n = Lan; }
         ty = INT;
         break;
      case Or: // push the current value, calculate the right value
         next(); a = n;
         if (compound) { compound = 0; expr(Assign); }
         else expr(Xor);
         bitopcheck(t, ty);
         if (*b == Num && b[1] == -1 && !hasSideEffect(n, b)) n = b;
         // else if (*n == Num && b[1] == -1 && !hasSideEffect(b, ?))
         //   { b[x] = Num; b[x+1] = -1; n = &b[x]; }
         else {
            switch(elideZero(a, b, t, Num)) {
               case 0: *--n = (int) b; *--n = Or; break;
               case 1: b[1] |= n[1]; n += 2;
            }
         }
         ty = INT;
         break;
      case Xor:
         next(); a = n;
         if (compound) { compound = 0; expr(Assign); }
         else expr(And);
         bitopcheck(t, ty);
         switch(elideZero(a, b, t, Num)) {
            case 0: *--n = (int) b; *--n = Xor; break;
            case 1: b[1] ^= n[1]; n += 2;
         }
         ty = INT;
         break;
      case And:
         next();
         if (compound) { compound = 0; expr(Assign); }
         else expr(Eq);
         bitopcheck(t, ty);
         if (*n == Num && n[1] == -1) n += 2;
         else if (*b == Num && b[1] == -1) swapDrop(b, 2);
         else if (*b == Num && b[1] == 0 && !hasSideEffect(n, b)) n = b;
         //if (*n == Num && n[1] == 0 && !hasSideEffect(b, ???))
         //    { b[x] = Num; b[x+1] = 0; n = &b[x]; }
         else if (*n == Num && *b == Num) { b[1] &= n[1]; n += 2; }
         else { *--n = (int) b; *--n = And; }
         ty = INT;
         break;
      case Eq:
         next(); expr(Ge); typecheck(Eq, t, ty);
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1];
               c2->i = (c2->f == c1->f) ? (btrue ? -1 : 1) : 0;
               n += 2; *b = Num;
            }
            else { *--n = (int) b; *--n = EqF; }
         } else {
            if (*n == Num && *b == Num) {
               b[1] = (b[1] == n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
            }
            else { *--n = (int) b; *--n = Eq; }
         }
         ty = INT;
         break;
      case Ne:
         next(); expr(Ge); typecheck(Ne, t, ty);
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1];
               c2->i = (c2->f != c1->f) ? (btrue ? -1 : 1) : 0;
               n += 2; *b = Num;
            }
            else { *--n = (int) b; *--n = NeF; }
         } else {
            if (*n == Num && *b == Num) {
               b[1] = (b[1] != n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
            }
            else { *--n = (int) b; *--n = Ne; }
         }
         ty = INT;
         break;
      case Ge:
         next(); expr(Shl); typecheck(Ge, t, ty);
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1];
               c2->i = (c2->f >= c1->f) ? (btrue ? -1 : 1) : 0;
               n += 2; *b = Num;
            }
            else { *--n = (int) b; *--n = GeF; }
         } else {
            if (*n == Num && *b == Num) {
               b[1] = (b[1] >= n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
            }
            else { *--n = (int) b; *--n = Ge; }
         }
         ty = INT;
         break;
      case Lt:
         next(); expr(Shl); typecheck(Lt, t, ty);
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1];
               c2->i = (c2->f < c1->f) ? (btrue ? -1 : 1) : 0;
               n += 2; *b = Num;
            }
            else { *--n = (int) b; *--n = LtF; }
         } else {
            if (*n == Num && *b == Num) {
               b[1] = (b[1] < n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
            }
            else { *--n = (int) b; *--n = Lt; }
         }
         ty = INT;
         break;
      case Gt:
         next(); expr(Shl); typecheck(Gt, t, ty);
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1];
               c2->i = (c2->f > c1->f) ? (btrue ? -1 : 1) : 0;
               n += 2; *b = Num;
            }
            else { *--n = (int) b; *--n = GtF; }
         } else {
            if (*n == Num && *b == Num) {
               b[1] = (b[1] > n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
            }
            else { *--n = (int) b; *--n = Gt; }
         }
         ty = INT;
         break;
      case Le:
         next(); expr(Shl); typecheck(Le, t, ty);
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1];
               c2->i = (c2->f <= c1->f) ? (btrue ? -1 : 1) : 0;
               n += 2; *b = Num;
            }
            else { *--n = (int) b; *--n = LeF; }
         } else {
            if (*n == Num && *b == Num) {
               b[1] = (b[1] <= n[1]) ? (btrue ? -1 : 1) : 0; n += 2;
            }
            else { *--n = (int) b; *--n = Le; }
         }
         ty = INT;
         break;
      case Shl:
         next();
         if (compound) { compound = 0; expr(Assign); }
         else expr(Add);
         bitopcheck(t, ty);
         if (*n == Num && *b == Num) {
            if (n[1] < 0) b[1] >>= -n[1];
            else b[1] <<= n[1];
            n += 2;
         }
         else if (*n == Num && n[1] == 0) n += 2;
         else if (*b == Num && b[1] == 0 && !hasSideEffect(n, b)) n = b;
         else { *--n = (int) b; *--n = Shl; }
         ty = INT;
         break;
      case Shr:
         next();
         if (compound) { compound = 0; expr(Assign); }
         else expr(Add);
         bitopcheck(t, ty);
         if (*n == Num && *b == Num) {
            if (n[1] < 0) b[1] <<= -n[1];
            else b[1] >>= n[1];
            n += 2;
         }
         else if (*n == Num && n[1] == 0) n += 2;
         else if (*b == Num && b[1] == 0 && !hasSideEffect(n, b)) n = b;
         else { *--n = (int) b; *--n = Shr; }
         ty = INT;
         break;
      case Add:
         next(); a = n;
         if (compound) { compound = 0; expr(Assign); }
         else expr(Mul);
         typecheck(Add, t, ty);
         if (ty == FLOAT) {
            switch(elideZero(a, b, t, NumF)) {
               case 0: *--n = (int) b; *--n = AddF; break;
               case 1: c1 = &n[1]; c2 = &b[1]; c2->f += c1->f; n += 2;
            }
         }
         else if ((*n == Num && n[1] == 0) ||
                  (*a == Num && a[1] == 0)) { // 0 + anything
            switch(elideZero(a, b, t, Num)) {
               case 0: goto careful_addition;
               case 1: b[1] += n[1]; n += 2;
            }
         }
         else { // either (1) both int (2) one is ptr, one is int
careful_addition:
            tc = ((t | ty) & (PTR | PTR2)) ? (t >= PTR) : (t >= ty);
            c = n; if (tc) ty = t; // set result type
            sz = (ty >= PTR2) ? sizeof(int) :
                 ((ty >= PTR) ? tsize[(ty - PTR) >> 2] : 1);
            if (*n == Num && tc) { n[1] *= sz; sz = 1; }
            else if (*b == Num && !tc) { b[1] *= sz; sz = 1; }
            if (*n == Num && *b == Num) { b[1] += n[1]; n += 2; }
            else if (sz != 1) {
               *--n = sz; *--n = Num;
               *--n = (int) (tc ? c : b); *--n = Mul;
               *--n = (int) (tc ? b : c); *--n = Add;
            }
            else { *--n = (int) b; *--n = Add; }
         }
         break;
      case Sub:
         next();
         if (compound) { compound = 0; expr(Assign); }
         else expr(Mul);
         typecheck(Sub, t, ty);
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) { 
               c1 = &n[1]; c2 = &b[1]; c2->f -= c1->f; n += 2;
            }
            else if (*n == NumF && n[1] == 0) n += 2;
            // else if (*b == NumF && b[1] == 0)  do Fneg
            else { *--n = (int) b; *--n = SubF; }
         }
         else if (*n == Num && n[1] == 0) n += 2;
         else { // 4 cases: ptr-ptr, ptr-int, int-ptr (err), int-int
            if (t >= PTR) { // left arg is ptr
               sz = (t >= PTR2) ? sizeof(int) : tsize[(t - PTR) >> 2];
               if (ty >= PTR) { // ptr - ptr
                  if (*n == Num && *b == Num) {
                     b[1] = (b[1] - n[1]) / sz; n += 2;
                  }
                  else {
                     *--n = (int) b; *--n = Sub;
                     if (sz > 1) {
                        if ((sz & (sz - 1)) == 0) { // 2^n
                           *--n = popcount32(sz - 1); *--n = Num;
                           --n; *n = (int) (n + 3); *--n = Shr;
                        }
                        else {
                           *--n = sz; *--n = Num; --n; *n = (int) (n + 3);
                           *--n = Div; ef_getidx("__aeabi_idiv");
                        }
                     }
                  }
                  ty = INT;
               }
               else { // ptr - int
                  if (*n == Num) {
                     n[1] *= sz;
                     if (*b == Num) { b[1] -= n[1]; n += 2; }
                     else { *--n = (int) b; *--n = Sub; }
                  }
                  else {
                     if (sz > 1) {
                        if ((sz & (sz - 1)) == 0) { // 2^n
                           *--n = popcount32(sz - 1); *--n = Num;
                           --n; *n = (int) (n + 3); *--n = Shl;
                        }
                        else {
                           *--n = sz; *--n = Num;
                           --n; *n = (int) (n + 3); *--n = Mul;
                        }
                     }
                     *--n = (int) b; *--n = Sub;
                  }
                  ty = t;
               }
            }
            else { // int - int
               if (*n == Num && *b == Num) { b[1] -= n[1]; n += 2; }
               else { *--n = (int) b; *--n = Sub; }
               ty = INT;
            }
         }
         break;
      case Mul:
         next();
         if (compound) { compound = 0; expr(Assign); }
         else expr(Inc);
         typecheck(Mul, t, ty);
         if ((*n == Num && n[1] == 1) ||
             (*n == NumF && n[1] == 0x3f800000)) { // 1.0
            n += 2; ty = t; break;
         }
         if ((*b == Num && b[1] == 1) ||
             (*b == NumF && b[1] == 0x3f800000)) { // 1.0
            swapDrop(b, 2); break;
         }
mod1_to_mul0:
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1] ; c2->f *= c1->f; n += 2;
            }
            else if (*b == NumF && b[1] == 0 && !hasSideEffect(n, b)) n = b;
            // else if (*n == NumF && n[1] == 0 && !hasSideEffect(b, ?)) {
            //    { b[x] = NumF; b[x+1] = 0; n = &b[x]; }
            else { *--n = (int) b; *--n = MulF; }
         }
         else if (*b == Num && b[1] == 0 && !hasSideEffect(n, b)) n = b;
         // else if (*n == Num && n[1] == 0 && !hasSideEffect(b, ?)) {
         //    { b[x] = Num; b[x+1] = 0; n = &b[x]; }
         else {
            if (*n == Num && *b == Num) { b[1] *= n[1]; n += 2; }
            else {
               *--n = (int) b;
               if (n[1] == Num && n[2] > 0 && (n[2] & (n[2] - 1)) == 0) {
                  n[2] = popcount32(n[2] - 1); *--n = Shl; // 2^n
               }
               else *--n = Mul;
            }
            ty = INT;
         }
         break;
      case Inc:
      case Dec:
         if (ty & 3) fatal("can't inc/dec an array variable");
         if (ty == FLOAT) fatal("no ++/-- on float");
         sz = (ty >= PTR2) ? sizeof(int) :
              ((ty >= PTR) ? tsize[(ty - PTR) >> 2] : 1);
         if (*n != Load) fatal("bad lvalue in post-increment");
         modArgCheck(n + 2); id->flags |= (8 | 64); // written, not lit cnst
         *n = tk; *--n = sz; *--n = Num;
         *--n = (int) b; *--n = (tk == Inc) ? Sub : Add;
         next();
         break;
      case Div:
         next();
         if (compound) { compound = 0; expr(Assign); }
         else expr(Inc);
         if ((*n == Num || *n == NumF) && n[1] == 0) fatal("division by zero");
         typecheck(Div, t, ty);
         if ((*n == Num && n[1] == 1) ||
                  (*n == NumF && n[1] == 0x3f800000)) {
            n += 2; ty = t; break;
         }
         if (ty == FLOAT) {
            if (*n == NumF && *b == NumF) {
               c1 = &n[1]; c2 = &b[1] ; c2->f /= c1->f; n += 2;
            }
            else { *--n = (int) b; *--n = DivF; }
         }
         else {
            if (*n == Num && *b == Num) {
               b[1] /= n[1]; n += 2;
            }
            else {
               *--n = (int) b;
               if (n[1] == Num && n[2] > 0 && (n[2] & (n[2] - 1)) == 0) {
                  n[2] = popcount32(n[2] - 1); *--n = Shr; // 2^n
               } else {
                  *--n = Div;
                  ef_getidx("__aeabi_idiv");
               }
            }
            ty = INT;
         }
         break;
      case Mod:
         next();
         if (compound) { compound = 0; expr(Assign); }
         else expr(Inc);
         if ((*n == Num || *n == NumF) && n[1] == 0) fatal("division by zero");
         typecheck(Mod, t, ty);
         if ((*n == Num && n[1] == 1) ||
                  (*n == NumF && n[1] == 0x3f800000)) {
            n[1] = 0; goto mod1_to_mul0;
         }
         if (ty == FLOAT) fatal("use fmodf() for float modulo");
         if (*n == Num && *b == Num) { b[1] %= n[1]; n += 2; }
         else {
            *--n = (int) b;
            if (n[1] == Num && n[2] > 0 && (n[2] & (n[2] - 1)) == 0) {
               --n[2]; *--n = And; // 2^n
            } else {
               *--n = Mod;
               ef_getidx("__aeabi_idivmod");
            }
         }
         ty = INT;
         break;
      case Dot:
         t += PTR;
         if (n[0] == Load && n[1] > ATOM_TYPE && n[1] < PTR) n += 2; // struct
      case Arrow:
         if (t <= PTR+ATOM_TYPE || t >= PTR2) fatal("structure expected");
         if (tokloc) {
            masgn = mns = 1; // these are for Alias state machine
            int otk = tokloc; tokloc = 1; next(); tokloc = otk;
            mns = 0; // for Alias state machine
         }
         else next();
         if (tk != Id) fatal("structure member expected");
         m = members[(t - PTR) >> 2];
         while (m && (m->hash != id->hash || strcmp(m->id, id->name)))
            m = m->next;
         if (tokloc && id == symlh && id->val == 0) ++symlh;
         if (!m) fatal("structure member not found");
         if (m->offset) {
            *--n = m->offset; *--n = Num; --n; *n = (int) (n + 3);
            *--n = Add;
         }
         ty = m->type; next();
         if (!(ty & 3)) {
            *--n = (ty >= PTR) ? INT : ty; *--n = Load; break;
         }
         memsub = 1; int dim = ty & 3, ee = m->etype; b = n; t = ty & ~3;
      case Bracket:
         if (t < PTR) fatal("pointer type expected");
         if (memsub == 0) { dim = id->type & 3, ee = id->etype; }
         int sum = 0, ii = dim - 1, *f = 0;
         int doload = 1; memsub = 0;
         sz = ((t = t - PTR) >= PTR) ? sizeof(int) : tsize[t >> 2];
         do {
            if (dim && tk != Bracket) { // ptr midway for partial subscripting
              t += PTR*(ii+1); doload = 0; break;
            }
            next(); expr(Assign); if (ty >= FLOAT) fatal("non-int array index");
            if (tk != ']') fatal("close bracket expected");
            c = n; next();
            if (dim) {
               int factor = ((ii == 2) ? (((ee>>11) & 0x3ff) + 1) : 1);
               factor *= ((dim == 3 && ii >= 1) ? ((ee & 0x7ff) + 1) :
                        ((dim == 2 && ii == 1) ? ((ee & 0xffff) + 1) : 1)) ;
               if (*n == Num) {
                  // elision with struct offset for efficiency
                  if (*b == Add && b[2] == Num) b[3] += factor * n[1] * sz;
                  else sum += factor * n[1];
                  n += 2; // delete the subscript constant
               }
               else {
                  // generate code to add a term
                  if (factor > 1) {
                     *--n = factor; *--n = Num;
                     *--n = (int) c; *--n = Mul;
                  }
                  if (f) { *--n = (int) f; *--n = Add; }
                  f = n;
               }
            }
         } while (--ii >= 0) ;
         if (dim) {
            if (sum != 0) {
               if (f) {
                  *--n = sum; *--n = Num;
                  *--n = (int) f; *--n = Add;
               }
               else { sum *= sz; sz = 1; *--n = sum; *--n = Num; }
            }
            else if (!f) goto add_simple;
         }
         if (sz > 1) {
            if (*n == Num) n[1] *= sz;
            else {
               *--n = sz; *--n = Num; --n; *n = (int) (n + 3); *--n = Mul;
            }
         }
         if (*n == Num && *b == Num) { b[1] += n[1]; n += 2; }
         else { *--n = (int) b; *--n = Add; }
add_simple:
         if (doload) { *--n = ((ty = t) >= PTR) ? INT : ty; *--n = Load; }
         break;
      case Alias:
         fatal(":= can only be used as a declaration initializer");
      default:
         printf("%s: compiler error tk=%d\n", linestr(), tk); exit(-1);
      }
   }
}

void init_array(struct ident_s *tn, int extent[], int dim)
{
   int i, cursor, match, coff = 0, off, empty, *vi;
   int inc[3];

   if (tn->class != Glo) fatal("array init only supported at global scope");
   inc[0] = extent[dim-1];
   for (i = 1; i < dim; ++i) inc[i] = inc[i-1] * extent[dim-(i+1)];

   // Global is preferred to local.
   // Either suggest global or automatically move to global scope.
   if (tn->class != Glo) fatal("only global array initialization supported");

   switch (tn->type & ~3) {
      case (CHAR  | PTR2) : match = CHAR + PTR2; break;
      case (CHAR  | PTR ) : match = CHAR + PTR; coff = 1; break; // strings
      case (INT   | PTR ) : match = INT; break;
      case (FLOAT | PTR ) : match = FLOAT; break;
      default:
         fatal("array-init must be literal ints, floats, or strings");
   }

   vi = (int *) tn->val; i = 0; cursor = (dim - coff);
   do {
      if (tk == '{') {
         next();
         if (cursor) --cursor;
         else fatal("overly nested initializer");
         empty = 1; continue;
      }
      else if (tk == '}') {
         next();
         // skip remainder elements on this level (or set 0 if cmdline opt)
         if ((off = i % inc[cursor+coff]) || empty)
            i += (inc[cursor+coff] - off);
         if (++cursor == dim - coff) break;
      }
      else {
         expr(Cond);
         if (*n != Num && *n != NumF) fatal("non-literal initializer");

         if (ty == CHAR + PTR) {
            if (match == CHAR + PTR2) {
               vi[i++] = n[1];
            }
            else if (match == CHAR + PTR) {
               off = strlen((char *) n[1]) + 1;
               if (off > inc[0]) {
                  off = inc[0];
                  printf("%s: string '%s' truncated to %d chars\n",
                         linestr(), (char *) n[1], off);
               }
               memcpy((char *)vi + i, (char *) n[1], off);
               i += inc[0];
            }
            else fatal("can't assign string to scalar");
         }
         else if (ty == match) { vi[i++] = n[1]; }
         else if (ty == INT) {
            if (match == CHAR + PTR) { *((char *) vi + i) = n[1]; i += inc[0];}
            else { *((float *)(n+1)) = (float) n[1]; vi[i++] = n[1]; }
         }
         else if (ty == FLOAT) {
            if (match == INT) { vi[i++] = (int) *((float *)(n+1)); }
            else fatal("illegal char/string initializer");
         }
         n += 2; // clean up AST
         empty = 0;
      }
      if (tk == ',') next();
   } while(1);
   tn->flags |= 4;
}

int isPrintf(char *s)
{
   char *ss = s;
   while(*ss) ++ss;
   return ((ss - s) < 6) ? 0 : !strcmp(ss - 6,"printf");
}

// AST parsing for IR generatiion
// With a modular code generator, new targets can be easily supported such as
// native Arm machine code.
void gen(int *n)
{
   int i = *n, j, k, l, isPrtf;
   int *a, *b, *c, *d, *t;
   struct ident_s *label;

   switch (i) {
   case Num: *++e = IMM; *++e = n[1]; break;   // int value
   case NumF: *++e = IMMF; *++e = n[1]; break; // float value
   case Load:
      gen(n + 2); // load the value
      if (n[1] > ATOM_TYPE && n[1] < PTR) // unreachable?
         fatal("struct copies not yet supported");
      *++e = (n[1] >= PTR) ? LI : LC + (n[1] >> 2);
      break;
   case Loc: *++e = LEA; *++e = n[1]; break;       // get address of variable
   case '{': gen((int *) n[1]); gen(n + 2); break; // parse AST expr or stmt
   case Assign: // assign the value to variables
      gen((int *) n[2]); *++e = PSH; gen(n + 3); l = n[1] & 0xffff;
      // Add SC/SI instruction to save value in register to variable address
      // held on stack.
      if (l > ATOM_TYPE && l < PTR) fatal("struct assign not yet supported");
      if ((n[1] >> 16) == FLOAT && l == INT) *++e = FTOI;
      else if ((n[1] >> 16) == INT && l == FLOAT) *++e = ITOF;
      *++e = (l >= PTR) ? SI : SC + (l >> 2);
      break;
   case Inc: // increment or decrement variables
   case Dec:
      gen(n + 2);
      *++e = PSH; *++e = (n[1] == CHAR) ? LC : LI; *++e = PSH;
      *++e = IMM; *++e = (n[1] >= PTR2) ? sizeof(int) :
                         ((n[1] >= PTR) ? tsize[(n[1] - PTR) >> 2] : 1);
      *++e = (i == Inc) ? ADD : SUB;
      *++e = (n[1] == CHAR) ? SC : SI;
      break;
   case Cond: // if else condition case
      gen((int *) n[1]); // condition
      // Add jump-if-zero instruction "BZ" to jump to false branch.
      // Point "b" to the jump address field to be patched later.
      *++e = BZ; b = ++e;
      gen((int *) n[2]); // expression
      // Patch the jump address field pointed to by "b" to hold the address
      // of false branch. "+ 3" counts the "JMP" instruction added below.
      //
      // Add "JMP" instruction after true branch to jump over false branch.
      // Point "b" to the jump address field to be patched later.
      if (n[3]) {
         *b = (int) (e + 3); *++e = JMP; b = ++e; gen((int *) n[3]);
      } // else statment
      // Patch the jump address field pointed to by "d" to hold the address
      // past the false branch.
      *b = (int) (e + 1);
      lastLEV = 0;
      break;
   // operators
   /* If current token is logical OR operator:
    * Add jump-if-nonzero instruction "BNZ" to implement short circuit.
    * Point "b" to the jump address field to be patched later.
    * Parse RHS expression.
    * Patch the jump address field pointed to by "b" to hold the address past
    * the RHS expression.
    */
   case Lor:  gen((int *) n[1]); *++e = BNZ;
              b = ++e; gen(n + 2); *b = (int) (e + 1); break;
   case Lan:  gen((int *) n[1]); *++e = BZ;
              b = ++e; gen(n + 2); *b = (int) (e + 1); break;
   /* If current token is bitwise OR operator:
    * Add "PSH" instruction to push LHS value in register to stack.
    * Parse RHS expression.
    * Add "OR" instruction to compute the result.
    */
   case Or:   gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = OR; break;
   case Xor:  gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = XOR; break;
   case And:  gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = AND; break;
   case Eq:   gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = EQ; break;
   case Ne:   gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = NE; break;
   case Ge:   gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = GE; break;
   case Lt:   gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = LT; break;
   case Gt:   gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = GT; break;
   case Le:   gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = LE; break;
   case Shl:  gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = SHL; break;
   case Shr:  gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = SHR; break;
   case Add:  gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = ADD; break;
   case Sub:  gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = SUB; break;
   case Mul:  gen((int *) n[1]); *++e = PSH; gen(n + 2); *++e = MUL; break;
   case Div:  if (peephole) *++e = PHF;
              gen((int *) n[1]);
              if (peephole) *++e = PHD;
              *++e = PSH; gen(n + 2); *++e = DIV;
              if (peephole) *++e = PHR0;
              break;
   case Mod:  if (peephole) *++e = PHF;
              gen((int *) n[1]);
              if (peephole) *++e = PHD;
              *++e = PSH; gen(n + 2); *++e = MOD;
              if (peephole) *++e = PHR0;
              break;
   case AddF: gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = ADDF; break;
   case SubF: gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = SUBF; break;
   case MulF: gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = MULF; break;
   case DivF: gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = DIVF; break;
   case EqF:  gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = EQF; break;
   case NeF:  gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = NEF; break;
   case GeF:  gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = GEF; break;
   case LtF:  gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = LTF; break;
   case GtF:  gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = GTF; break;
   case LeF:  gen((int *) n[1]); *++e = PSHF; gen(n + 2); *++e = LEF; break;
   case CastF: gen((int *) n[1]); *++e = n[2]; break;
   case Func:
   case Syscall:
   case ClearCache:
      b = (int *) n[1]; k = b ? n[3] : 0;
      if (k) {
         if (i == Syscall) {
            isPrtf = (n[4] & 0xfc0) && isPrintf(ef_cache[n[2]]->name);
            if (isPrtf) {
               *++e = PHD; *++e = IMM; *++e = (k & 1)*4; *++e = VENT;
            }
         }
         a = (int *) malloc(sizeof(int) * k);
         for (j = 0; *b ; b = (int *) *b) a[j++] = (int) b;
         a[j] = (int) b;
         while (j >= 0) { // push arguments
            gen(b + 1);
            if (peephole) *++e = PHD;
            if (i == ClearCache)
               *++e = PSH;
            else
               *++e = (n[4 + (k-1-j+12)/32] & (1 << ((k-1-j+12)%32))) ?
                      PSHF : PSH;
            --j; b = (int *) a[j];
         }
         free(a);
      }
      if (i == Syscall) *++e = SYSC;
      if (i == Func) {
         label = (struct ident_s *) n[2];
         label->flags |= 2; // leaf function is not dead code
         *++e = JSR;
         if (label->val == 0) {
            *++e = (int) label->chain; label->chain = e;
         }
         else
            *++e = n[2];
      }
      else {
         *++e = n[2];
      }
      if (n[3] || i == Syscall) {
         *++e = ADJ; *++e = (i == Syscall) ? n[4] : n[3];
      }
      if (k && i == Syscall && isPrtf) *++e = VLEV;
      if (peephole && i != ClearCache) *++e = PHR0;
      break;
   case Fneg:
   case Fabs:
   case Sqrt: b = (int *) n[1]; gen(b + 1); *++e = n[2]; break;
   case While:
   case DoWhile:
      if (i == While && n[3] != 2) { *++e = JMP; a = ++e; }
      d = (e + 1);
      b = brks; brks = 0;
      c = cnts; cnts = 0;
      gen((int *) n[1]); // loop body
      if (i == While && n[3] != 2) *a = (int) (e + 1);
      while (cnts) { t = (int *) *cnts; *cnts = (int) (e + 1); cnts = t; }
      cnts = c;
      if (i != DoWhile || n[3] != 1) {
         if (n[3] == 0) gen((int *) n[2]); // condition
         *++e = (n[3] == 0) ? BNZ : JMP ; *++e = (int) d;
      }
      while (brks) { t = (int *) *brks; *brks = (int) (e + 1); brks = t; }
      brks = b;
      lastLEV = 0;
      break;
   case For:
      gen((int *) n[4]);  // init
      *++e = JMP; a = ++e;
      d = (e + 1);  
      b = brks; brks = 0;
      c = cnts; cnts = 0;
      gen((int *) n[3]); // loop body
      while (cnts) { t = (int *) *cnts; *cnts = (int) (e + 1); cnts = t; }
      cnts = c;
      gen((int *) n[2]); // increment
      *a = (int) (e + 1);
      gen((int *) n[1]); // condition
      *++e = BNZ; *++e = (int) d;
      while (brks) { t = (int *) *brks; *brks = (int) (e + 1); brks = t; }
      brks = b;
      lastLEV = 0;
      break;
   case Switch:
      gen((int *) n[1]); // condition
      a = cas; *++e = JMP; cas = ++e;
      b = brks; d = def; brks = def = 0;
      gen((int *) n[2]); // case statment
      // deal with no default inside switch case
      *cas = def ? (int) def : (int) (e + 1); cas = a;
      while (brks) { t = (int *) * brks; *brks = (int) (e + 1); brks = t; }
      brks = b; def = d;
      lastLEV = 0;
      break;
   case Case:
      *++e = JMP; ++e;
      a = 0;
      *e = (int) (e + 7); *++e = PSH; i = *cas; *cas = (int) e;
      gen((int *) n[1]); // condition
      if (*(e - 1) != IMM) fatal("case label not a numeric literal");
      *++e = SUB; *++e = BNZ; cas = ++e; *e = i + e[-3];
      if (*(int *) n[2] == Switch) a = cas;
      gen((int *) n[2]); // expression
      if (a != 0) cas = a;
      break;
   case Break:    *++e = JMP; *++e = (int) brks; brks = e; break;
   case Continue: *++e = JMP; *++e = (int) cnts; cnts = e; break;
   case Goto:
      label = (struct ident_s *) n[1];
      *++e = JMP; *++e = label->val;
      if (label->class == 0) label->val = (int) e; // Define label address later
      break;
   case Default: def = e + 1; gen((int *) n[1]); break;
   case Return:
      if (n[1]) gen((int *) n[1]);
      if (single_exit) {
         if (!numpts) { *++e = JMP; *++e = (int) rets; rets = e; }
      }
      else { *++e = LEV; lastLEV = e; }
      break;
   case Enter:
      *++e = ENT; *++e = n[1];
      if (single_exit) { b = rets; rets = 0; }
      gen(n + 2);
      if (single_exit) {
         while (rets) { t = (int *) *rets; *rets = (int) (e + 1); rets = t; }
         rets = b;
      }
      if (lastLEV != e) { *++e = LEV; lastLEV = e; }
      break;
   case Label: // target of goto
      label = (struct ident_s *) n[1];
      if (label->class != 0) fatal("duplicate label definition");
      d = e + 1; b = (int *) label->val;
      while (b && (b == e)) { e -= 2; d -= 2; b = (int *) *b; }
      while (b) { t = (int *) *b; *b = (int) d; b = t; }
      label->val = (int) d; label->class = Label;
      lastLEV = 0;
      break;
   case Phf: *++e = PHF; break;
   default:
      if (i != ';') {
         printf("%s: compiler error gen=%08x\n", linestr(), i); exit(-1);
      }
   }
}

int gen_etype(int ext[3], int d)
{
   int retVal ;
   switch(d) { // get permutation information
   case 1:
      retVal = (ext[0]-1); break;
   case 2:
      retVal = ((ext[0]-1) << 16) + (ext[1]-1);
      if (ext[0] > 32768 || ext[1] > 65536)
         fatal("max [32768][65536]");
      break;
   case 3:
      retVal = ((ext[0]-1) << 21) + ((ext[1]-1) << 11) + (ext[2]-1);
      if (ext[0] > 1024 || ext[1] > 1024 || ext[2] > 2048)
         fatal("max [1024][1024][2048]");
      break;
   }
   return retVal;
}

void loc_array_decl(int ct, int ext[3], int *dims, int *et, int *size)
{
   *dims = 0;
   do {
      next();
      if (*dims == 0 && ct == Par && tk == ']') {
         ext[*dims] = 1; next();
      }
      else {
         expr(Cond);
         if (*n != Num) fatal("non-const array size");
         if (n[1] <= 0) fatal("non-positive array dimension");
         if (tk != ']') fatal("missing ]");
         next(); ext[*dims] = n[1]; *size *= n[1]; n += 2;
      }
      ++*dims;
   } while (tk == Bracket && *dims < 3);
   if (tk == Bracket) fatal("three subscript max on decl");
   *et = gen_etype(ext, *dims);
}

// statement parsing (syntax analysis, except for declarations)
void stmt(int ctx)
{
   struct ident_s *dd, *td, *osymh, *osymt;
   int *a, *b, *c, *d;
   int i, j, tt, nf, atk, sz, old, toksav;
   int nd[3];
   int bt, tdef = 0;
   int inln_func = 0;
   char *psave;
   int dodeadcode;

   if (ctx == Glo && (tk < TypeId || tk > Union) && tk != Inln)
      fatal("syntax: statement used outside function");

process_inln:
   switch (tk) {
   // stmt -> ';'
   case ';':
      next();
      *--n = ';';
      return;
   case Id:
inln_func_expr:
      sbegin = 1; expr(Assign);
      if (!sbegin) {
         while (tk == ',' && ctx == Loc && !inDecl) {
            int *t;
            next(); t = n; expr(Assign);
            if (t != n) { *--n = (int) t; *--n = '{'; }
         }
         if (tk != ';' && tk != ',') fatal("semicolon expected");
         next();
      }
      sbegin = 0;
      return;
   case Typedef:
      next();
      switch (tk) {
      case Char:
      case Int:
      case Float:
      case Struct:
      case Union:
      case TypeId:
         tdef = 1; goto do_typedef;
      case Enum:
         printf("Enum not supported for typedef\n");
      default: fatal("bad typedef declaration");
      }
   case Enum:
      next();
      // If current token is not "{", it means having enum type name.
      // Skip the enum type name.
      if (tk == Id) next();
      if (tokloc) ++tokloc;
      if (tk == '{') {
         next();
         i = 0; // Enum value starts from 0
         while (tk != '}') {
            if (tokloc) --tokloc;
            // Current token should be enum name.
            // If current token is not identifier, stop parsing.
            if (tk != Id) fatal("bad enum identifier");
            dd = id; next();
            if (tk == Assign) {
               next();
               expr(Cond);
               if (*n != Num) fatal("bad enum initializer");
               i = n[1]; n += 2; // Set enum value
            }
            dd->class = Num; dd->type = INT; dd->val = i++; dd->flags |= 4;
            if (tk == ',') { if (tokloc) ++tokloc; next(); }
         }
         next(); // Skip "}"
      } else if (tk == Id) {
         if (ctx != Par) fatal("enum can only be declared as parameter");
         id->type = INT; id->class = ctx; id->val = ld++;
         if (src == 2) {
            ir_var[ir_count].loc = id->val;
            ir_var[ir_count++].name = id->name;
         }
         if (tokloc) --tokloc;
         next();
      }
      return;
   case Char:
   case Int:
   case Float:
   case Struct:
   case Union:
   case TypeId:
do_typedef:
      dd = id; td = 0;
      switch (tk) {
      case TypeId:
         td = id; bt = td->type;
         if (tokloc) tokloc = 2;
         next(); break;
      case Char:
      case Int:
      case Float:
         bt = (tk - Char) << 2;
         if (tokloc) tokloc = 2;
         next(); break;
      case Struct:
      case Union:
         atk = tk; next();
         if (tokloc) tokloc = 2;
         if (tk == Id) {
            if (!id->type) id->type = tnew++ << 2;
            bt = id->type;
            next();
         } else {
            bt = tnew++ << 2;
         }
         if (tk == '{') {
            if (members[bt >> 2]) fatal("duplicate structure definition");
            next();
            osymh = symlh; osymt = symlt; symlh = symlt = syms;
            toksav = tokloc; tokloc = 2;
            tsize[bt >> 2] = 0; // for unions
            i = 0;
            while (tk != '}') {
               int mbt = INT; // Enum
               switch (tk) {
               case TypeId:
                  mbt = id->type; next(); break;
               case Char:
               case Int:
               case Float:
                  mbt = (tk - Char) << 2; next(); break;
               case Struct:
               case Union:
                  tokloc = 1; next(); tokloc = 2;
                  if (tk != Id || id->type <= ATOM_TYPE || id->type >= PTR)
                     fatal("bad struct/union declaration");
                  mbt = id->type;
                  next(); break;
               }
               while (tk != ';') {
                  ty = mbt;
                  // if the beginning of * is a pointer type,
                  // then type plus `PTR` indicates what kind of pointer
                  while (tk == Mul) { next(); ty += PTR; }
                  if (tk != Id) fatal("bad struct member definition");
                  sz = (ty >= PTR) ? sizeof(int) : tsize[ty >> 2];
                  struct member_s *m = (struct member_s *)
                                       malloc(sizeof(struct member_s));
                  m->hash = id->hash; m->id = id->name; m->etype = 0; next();
                  if (tk == Bracket) {
                     --tokloc;
                     j = ty; loc_array_decl(0, nd, &nf, &m->etype, &sz);
                     ty = (j + PTR) | nf;
                     ++tokloc;
                  }
                  sz = (sz + 3) & -4;
                  m->offset = i;
                  m->type = ty;
                  m->next = members[bt >> 2];
                  members[bt >> 2] = m;
                  i += sz;
                  if (atk == Union) {
                     if (i > tsize[bt >> 2]) tsize[bt >> 2] = i; i = 0;
                  }
                  if (tk == ',') next();
               }
               next();
            }
            tokloc = toksav; symlh = osymh; symlt = osymt;
            next();
            if (atk != Union) tsize[bt >> 2] = i;
         }
         break;
      }
      /* parse statement such as 'int a, b, c;'
       * "enum" finishes by "tk == ';'", so the code below will be skipped.
       * While current token is not statement end or block end.
       */
      b = 0; ++inDecl;
      while (tk != ';' && tk != '}' && tk != ',' && tk != ')') {
         ty = bt;
         // if the beginning of * is a pointer type, then type plus `PTR`
         // indicates what kind of pointer
         if (tk == Mul && td && (td->type & 3))
            fatal("typedef'd tensor ptr decls not supported... yet");
         while (tk == Mul) { next(); ty += PTR; }
         if (tk != Id || id->class >= ctx) {
            char errmsg[64];
            strcpy(errmsg, "bad/duplicate ");
            strcat(errmsg, (ctx == Glo) ? "global" :
                          ((ctx == Loc) ? "local" : "parameter"));
            strcat(errmsg, " declaration/definition");
            fatal(errmsg);
         }
         next();
         if (tk == '(') {
            rtf = 0; rtt = (ty == 0 && !memcmp(dd->name, "void", 4)) ? -1 : ty;
         }
         else if (inln_func == 1) {
            fatal("inline keyword can only be applied to func definition");
         }
         dd = id; dd->type = ty;
         if (tk == '(') { // function
            int *saven = 0;
            if (tdef) fatal("typedef can't be function");
            if (b != 0) fatal("func decl can't be mixed with var decl(s)");
            if (ctx != Glo) fatal("nested function");
            if (ty > ATOM_TYPE && ty < PTR)
               fatal("return type can't be struct");
            if (id->class == Syscall && id->val)
               fatal("forward decl location failed one pass compilation");
            if (id->class == Func &&
               id->val > (int) text && id->val < (int) e)
               fatal("duplicate global definition");
            fspec[numfspec] = (int *) idp;
            fspec[numfspec][0] = (int) dd->name; // func name
            idp += 56 * sizeof(int);
            saven = n;
            dd->ftype[0] = dd->ftype[1] = 0; dd->class = Func;
            dd->val = (int) (e + 1);
            symlh = symlt; labt = lab; idl = idln; tokloc = 1; next();
            nf = ir_count = ld = maxld = ldn = lds[0] = 0; // ld is param index
            while (tk != ')') {
               stmt(Par);
               if (ty == FLOAT) {
                  ++nf; dd->ftype[(ld+11)/32] |= 1 << ((ld+11) % 32);
               }
               fspec[numfspec][3+ld] = (int) id->name;
               if (tk == ',') next();
            }
            if (ld > MAX_FARG) fatal("maximum of 52 function parameters");
            next(); dd->ftype[0] += (nf << 6) + ld;
            if (dd->val != (int) (e + 1))
               fatal("func def internal compiler error");
            if (tk == ';') {
               if (inln_func) dd->flags |= 1; // forward declaration
               inln_func = 0;
               dd->val = 0; goto unwind_func;
            } // fn proto
            if (tk != '{') fatal("bad function definition");
            if (inln_func) {
               ++pinlndef;
               dd->tsub = (char *) (numfspec + 1);
               dd->val = 0;
            }
            fspec[numfspec][1] = (int) p;  // func body char* after '{'
            fspec[numfspec][2] = line;     // first source line func body
            fspec[numfspec++][3] = (int) ld; // number of func param names
            // fspec param names are in slot 4 onward.
            if (dd->val && dd->chain) { // backpatch fwd decl func addrs
               int *patch = dd->chain;
               while (patch) {
                  int *t = (int *) *patch; *patch = (int) dd; patch = t;
               }
               dd->chain = 0;
            }
            loc = ++ld;
            --inDecl; next();
            oline = -1; osize = -1; oname = 0; // optimization hint
            // Not declaration and must not be function, analyze inner block.
            // e represents the address which will store pc
            // (ld - loc) indicates memory size to allocate
            *--n = ';';
            while (tk != '}') {
               int *t = n; stmt(Loc);
               if (t != n) { *--n = (int) t; *--n = '{'; }
            }
            ++inDecl; if (inln_func) --pinlndef;
            if (rtf == 0 && rtt != -1) fatal("expecting return value");
            if (*p == '\n' || *p == ' ') {
               if (lp < p && !numpts) {
                  if (src) printf("%d: %.*s", line, p - lp + 1, lp);
                  lp = p + 1;
               }
               if (*p == '\n') ++line;
            }
            else
               fatal("char after function body decl must be whitespace");
            *p++ = 0;
            if (ld > maxld) maxld = ld;
            *--n = maxld - loc; *--n = Enter;
            if (oname && n[1] > 64 && osize > 64)
               printf("--> %d: move %s to global scope for performance.\n",
                      oline, oname);
            cas = 0;
            if (!inln_func) gen(n); else n = saven;
            if (src && !numpts && !inln_func) {
               int *base = le;
               printf("%d: %.*s\n", line, p - lp, lp);
               lp = p;
               while (le < e) {
                  int off = le - base; // Func IR instruction memory offset
                  printf("%04d: %8.4s", off,
                        & "LEA  IMM  IMMF JMP  JSR  BZ   BNZ  ENT  ADJ  LEV  "
                          "PSH  PSHF LC   LI   LF   SC   SI   SF   "
                          "OR   XOR  AND  EQ   NE   GE   LT   GT   LE   "
                          "SHL  SHR  ADD  SUB  MUL  DIV  MOD  "
                          "ADDF SUBF MULF DIVF FTOI ITOF "
                          "EQF  NEF  GEF  LTF  GTF  LEF  FNEG FABS SQRT "
                          "SYSC CLCA VENT VLEV PHD  PHF  PHR0" [*++le * 5]);
                  if (*le < ADJ) {
                     struct ident_s *scan;
                     ++le;
                     if (*le > (int) base && *le <= (int) e)
                        printf(" %04d\n", off + ((*le - (int) le) >> 2) + 1);
                     else if (*(le - 1) == LEA && src == 2) {
                        int ii, irf = 0;
                        for (ii = 0; ii < ir_count; ++ii)
                           if (loc - ir_var[ii].loc == *le) {
                              printf(" %s", ir_var[ii].name);
                              irf = 1;
                           }
                        if (irf) printf(" (%d)\n", *le);
                     }
                     else if (*(le - 1) == IMMF)
                        printf(" %#g\n", *((float *) le));
                     else if ((*le & 0xf0000000) &&
                              (*le > 0 || -*le > 0x1000000)) {
                        int cval = (*(le-1) != JSR) ? (*le) :
                           (((struct ident_s *)(*le))->val) ;
                        for (scan = symk; scan->tk; ++scan)
                           if (scan->val == cval) {
                              printf(" &%s", scan->name);
                              if (src == 2) printf(" (0x%08x)", cval);
                              printf("\n");
                              break;
                           }
                        if (!scan->tk) printf(" 0x%08x\n", cval);
                     }
                     else
                        printf(" %d\n", *le);
                  }
                  else if (*le == ADJ) {
                     ++le;
                     printf(" %d\n", *le & 0xf);
                  }
                  else if (*le == SYSC) {
                     printf(" %s\n", ef_cache[*(++le)]->name);
                  }
                  else printf("\n");
               }
            }
unwind_func:
            while (--labt >= lab) {
               if ((labt->class == 0 && labt->type == -1) || labt->flags) {
                  if ((*((int *) labt->name) & 0xffffff) != 0x6c7269) {
                     printf("%s: label %s not defined\n",
                            linestr(), labt->name);
                     exit(-1);
                  }
               }
            }
            tokloc = 0;
         }
         else {
            if (ty > ATOM_TYPE && ty < PTR && tsize[bt >> 2] == 0)
               fatal("struct forward decl not supported... yet");
            dd->class = ctx;
            dd->type = ty;
            if (tdef) dd->val = ty; //save fundamental type
            sz = (ty >= PTR) ? sizeof(int) : tsize[ty >> 2];
            if (tk == Bracket) {
               if (td && (td->type & 3))
                  fatal("can't stack typedef subscripts...yet");
               if (tokloc) --tokloc;
               i = ty; loc_array_decl(ctx, nd, &j, &dd->etype, &sz);
               dd->flags |= 4; // mark loc array inited as approximation
               ty = (i + PTR) | j; dd->type = ty;
               if (tokloc) ++tokloc;
            }
            else if (td && (td->type & 3)) {
               dd->etype = td->etype;
               sz *= tensor_size(td->type & 3, td->etype);
            }
            if (tdef) {
               dd->tk = TypeId; goto next_type;
            }
            sz = (sz + 3) & -4;
            if (ctx == Loc && sz > osize) {
               osize = sz; oline = line; oname = dd->name;
            }
            if (ctx == Glo) { dd->val = (int) data; data += sz; }
            else if (ctx == Loc) {
               int ii, tmp;
               tmp = dd->val = (ld += sz / sizeof(int));
               if (src == 2) {
                  for (ii=0; ii<ir_count; ++ii) {
                     if (ir_var[ii].loc == tmp &&
                         !strcmp(dd->name, ir_var[ii].name))
                        break;
                  }
                  if (ii == ir_count) {
                     ir_var[ir_count].loc = tmp;
                     ir_var[ir_count++].name = dd->name;
                  }
               }
            }
            else if (ctx == Par) {
               dd->val = ld++; dd->flags |= 4; // mark func args as inited
               if (ty > ATOM_TYPE && ty < PTR) // local struct decl
                  fatal("struct parameters must be pointers");
               if (src == 2) {
                  ir_var[ir_count].loc = dd->val;
                  ir_var[ir_count++].name = dd->name;
               }
            }
            if (tk == Assign || tk == Alias) {
               if (ctx == Par) fatal("default arguments not supported");
               if (tokloc) --tokloc;
               atk = tk;
               psave = p; // for alias
               masgn = 0; // for alias
               next();
               if (tk == '{' && (dd->type & 3)) init_array(dd, nd, j);
               else {
                  if (ctx == Loc) {
                     if (b == 0) *--n = ';'; j = (b == 0) ? 1 : 0;
                     b = n; *--n = loc - dd->val; *--n = Loc;
                     a = n; i = ty; expr(Assign); typecheck(Assign, i, ty);
                     if (atk == Alias) {
                        if (i <= ATOM_TYPE && (i & (INT+FLOAT)) && !masgn) {
                           if ((a == n+2) && (*n == Num || *n == NumF)) {
                              dd->class = *n; dd->val = n[1]; dd->flags |= 4;
                              --ld; n = b + j; if (j) b = 0;
                              if (src == 2) --ir_count;
                           }
                           else if ((a == n+4) && *n == Load && n[2] == Num) {
                              --ld; dd->val = n[3]; dd->class = Glo;
                              dd->flags |= 16; n = b + j; if (j) b = 0;
                              if (src == 2) --ir_count;
                           }
                           else if (((a == n+8) && *n == Load && n[2] == Add &&
                              n[4] == Num && n[6] == Loc && n[7] < 0) ||
                              ((a == n+4) && *n == Load &&
                                           n[2] == Loc && n[3] < 0)) {
                              dd->val = (a == n+4) ?
                                 (loc-n[3]) : (loc-n[7]) - n[5]/sizeof(int);
                              --ld; dd->flags |= 16; n = b+j; if (j) b = 0;
                              if (src == 2) ir_var[ir_count-1].loc = dd->val;
                           }
                           else if (((a == n+8) && (*n == Add || *n == Sub) &&
                                     n[2] == Num && n[4] == Load &&
                                     n[6] == Loc) ||
                                    ((a == n+10) && *n == Load &&
                                     n[2] == Add && n[4] == Num &&
                                     n[6] == Load && n[8] == Loc) ||
                                    ((a == n+6) && *n == Load &&
                                     n[2] == Load && n[4] == Loc)) {
                              dd->val = 0; // recursion flags
                              dd->tsub = idp;
                              memcpy(idp,psave,p-psave-1); idp[p-psave-1] = 0;
                              idp = (char *) (((int) idp +
                                               (p - psave) + sizeof(int)) &
                                              (-sizeof(int)));
                              --ld; if (src == 2) --ir_count;
                              n = b + j; if (j) b = 0;
                              dd->flags |= 16; // alias declaration
                           }
                           else goto do_assign;
                        }
                        else {
do_assign:
                           fatal("This specific alias semantic not supported");
                           atk = Assign;
                        }
                     }
                     if (atk == Assign) {
                        flagWrite(&dd->flags, a, n);  // var write
                        *--n = (int)a; *--n = (ty << 16) | i; *--n = Assign;
                        ty = i; *--n = (int) b; *--n = '{';
                     }
                  }
                  else { // ctx == Glo
                     a = n; i = ty; expr(Cond); typecheck(Assign, i, ty);
                     if (a - n != 2 || (*n != Num && *n != NumF))
                        fatal("global assignment must eval to lit expr");
                     if (ty == CHAR + PTR) {
                        if ((dd->type & 3) == 0)
                           *((int *) dd->val) = n[1];
                        else if ((dd->type & 3) != 1)
                           fatal("use decl char foo[nn] = \"...\";");
                        else { // 1d array of char
                           i = strlen((char *) n[1]) + 1;
                           if (i > (dd->etype + 1)) {
                               i = dd->etype + 1;
                               printf("%s: string truncated to width\n",
                                      linestr());
                           }
                           memcpy((char *) dd->val, (char *) n[1], i);
                        }
                     }
                     else if ((*n == Num && (i == CHAR || i == INT)) ||
                         (*n == NumF && i == FLOAT)) {
                        *((int *) dd->val) = n[1];
                     }
                     else fatal("unsupported global initializer");
                     n += 2;
                  }
               }
               if (tokloc) ++tokloc;
            }
         }
next_type:
         if (ctx != Par && tk == ',') next();
      }
      --inDecl; if (tokloc == 2) tokloc = 1;
      return;
   // stmt -> '{' stmt '}'
   case '{':
      next();
      lds[++ldn] = old = ld; osymh = symlh;
      *--n = ';';
      while (tk != '}') {
         a = n; stmt(ctx);
         if (a != n) { *--n = (int) a; *--n = '{'; }
      }
      if (ld > maxld) maxld = ld;
      --ldn; if (old < ld) { ld = old; symlh = osymh; }
      next();
      return;
   case If:
      dodeadcode = swtc ? 0 : 1; psave = p; i = line; dd = labt;
keepdeadcode_if:
      next();
      if (tk != '(') fatal("open parenthesis expected");
      next();
      c = n; expr(Assign); tt = ty; a = n;
      if (tk != ')') fatal("close parenthesis expected");
      next();
      // dead code elimination for const if-condition
      if (dodeadcode && (c-a == 2) && (*a == Num || *a == NumF)) {
         struct ident_s *labcheck;
         n += 2;
         if (a[1]) {
            stmt(ctx);
            if (tk == Else) { // discard if no labels created
               labcheck = labt;
               next(); c = n; j = maxld;
               ++pinlndef; ++deadzone; stmt(ctx); --deadzone; --pinlndef;
               if (labt != labcheck) {
                  dodeadcode = 0; p = psave; line = i; labt = dd; n = a + 2;
                  goto keepdeadcode_if;
               }
               n = c; maxld = j;
            }
         }
         else {
            labcheck = labt;
            c = n; j = maxld;
            ++pinlndef; ++deadzone; stmt(ctx); --deadzone; --pinlndef;
            if (labt != labcheck) {
               dodeadcode = 0; p = psave; line = i; labt = dd; n = a + 2;
               goto keepdeadcode_if;
            }
            n = c; maxld = j; // discard if no labels created
            if (tk == Else) { next(); stmt(ctx); }
         }
      }
      else {
         if (tt == FLOAT) {
            *--n = 0; *--n = NumF; --n; *n = (int) (n + 3); *--n = NeF; b = n;
         }
         stmt(ctx); b = n;
         if (tk == Else) { next(); stmt(ctx); d = n; } else d = 0;
         *--n = (int)d; *--n = (int) b; *--n = (int) a; *--n = Cond;
      }
      return;
   case While:
      dodeadcode = swtc ? 0 : 1; psave = p; i = line; dd = labt;
keepdeadcode_while:
      next();
      if (tk != '(') fatal("open parenthesis expected");
      next();
      c = n; expr(Assign); tt = ty; b = n; // condition
      if (tk != ')') fatal("close parenthesis expected");
      next(); ++brkc; ++cntc;
      // dead code elimination for const while-condition
      if (dodeadcode && (c-b == 2) &&
          (*b == Num || *b == NumF) && b[1] == 0) {
         struct ident_s *labcheck = labt;
         n += 2;
         c = n; j = maxld;
         ++pinlndef; ++deadzone; stmt(ctx); --deadzone; --pinlndef;
         --brkc; --cntc;
         if (labt != labcheck) {
            dodeadcode = 0; p = psave; line = i; labt = dd; n = b + 2;
            goto keepdeadcode_while;
         }
         n = c; maxld = j; // discard if no labels created
      }
      else {
         if (tt == FLOAT) {
            *--n = 0; *--n = NumF; --n; *n = (int) (n + 3); *--n = NeF; b = n;
         }
         stmt(ctx); a = n; // parse body of "while"
         --brkc; --cntc;
         if (c-b == 2 && (*b == Num || *b == NumF)) {
            *--n = (b[1] == 0) ? 1 : 2;
         }
         else *--n = 0;
         *--n = (int) b; *--n = (int) a; *--n = While;
      }
      return;
   case DoWhile:
      next();
      ++brkc; ++cntc;
      stmt(ctx); a = n; // parse body of "do-while"
      --brkc; --cntc;
      if (tk != While) fatal("while expected");
      next();
      if (tk != '(') fatal("open parenthesis expected");
      next();
      *--n = ';';
      c = n; expr(Assign); b = n;
      if (tk != ')') fatal("close parenthesis expected");
      next();
      if (c-b == 2 && (*b == Num || *b == NumF)) {
         *--n = (b[1] == 0) ? 1 : 2;
      }
      else {
         if (ty == FLOAT) {
            *--n = 0; *--n = NumF; --n; *n = (int) (n + 3); *--n = NeF; b = n;
         }
         *--n = 0;
      }
      *--n = (int) b; *--n = (int) a; *--n = DoWhile;
      return;
   case For:
      next();
      if (tk != '(') fatal("open parenthesis expected");
      lds[++ldn] = old = ld; osymh = symlh;
      next();
      *--n = ';';
      if (tk != ';') {
         stmt(ctx); if (tk == ';') next();
      }
      else next();
      d = n;
      *--n = ';';
      expr(Assign); a = n; // Point to entry of for cond
      if (ty == FLOAT) {
         *--n = 0; *--n = NumF; --n; *n = (int) (n + 3); *--n = NeF; a = n;
      }
      if (tk != ';') fatal("semicolon expected");
      next();
      *--n = ';';
      if (tk != ')') expr(Assign);
      while (tk == ',') {
         int *g = n; next(); expr(Assign); *--n = (int) g; *--n = '{';
      }
      b = n;
      if (tk != ')') fatal("close parenthesis expected");
      next();
      ++brkc; ++cntc;
      stmt(ctx); c = n;
      --brkc; --cntc;
      *--n = (int) d; *--n = (int) c; *--n = (int) b; *--n = (int) a;
      *--n = For;
      if (ld > maxld) maxld = ld;
      --ldn; if (old < ld) { ld = old; symlh = osymh; }
      return;
   case Switch:
      i = 0; j = 0;
      if (cas) j = (int) cas;
      cas = &i;
      next();
      if (tk != '(') fatal("open parenthesis expected");
      next();
      expr(Assign);
      a = n;
      if (tk != ')') fatal("close parenthesis expected");
      next();
      ++swtc; ++brkc;
      stmt(ctx);
      --swtc; --brkc;
      b = n;
      *--n = (int) b; *--n = (int) a; *--n = Switch;
      if (j) cas = (int *) j;
      return;
   case Case:
      if (!swtc) fatal("case-statement outside of switch");
      i = *cas;
      next();
      expr(Or);
      a = n;
      if (*n != Num) fatal("case label not a numeric literal");
      j = n[1]; n[1] -= i; *cas = j;
      *--n = ';';
      if (tk != ':') fatal("colon expected");
      next();
      stmt(ctx);
      b = n;
      *--n = (int) b;*--n = (int) a; *--n = Case;
      return;
   case Break:
      if (!brkc) fatal("misplaced break statement");
      next();
      if (tk != ';') fatal("semicolon expected");
      next();
      *--n = Break;
      return;
   case Continue:
      if (!cntc) fatal("misplaced continue statement");
      next();
      if (tk != ';') fatal("semicolon expected");
      next();
      *--n = Continue;
      return;
   case Default:
      if (!swtc) fatal("default-statement outside of switch");
      next();
      if (tk != ':') fatal("colon expected");
      next();
      stmt(ctx); a = n;
      *--n = (int) a; *--n = Default;
      return;
   // RETURN_stmt -> 'return' expr ';' | 'return' ';'
   case Return:
      if (numpts) { // inline code handler
         next();
         if (tk != ';') {
            expr(Assign);
         }
         if (!deadzone) {
            a = n; ++(retlabel[numpts-1]->flags);
            *--n = (int) retlabel[numpts-1]; *--n = Goto;
            *--n = (int) a; *--n = '{';
         }
      }
      else {
         a = 0; next();
         if (tk != ';') {
            expr(Assign); a = n;
            if (rtt == -1) fatal("not expecting return value");
            typecheck(Eq, rtt, ty);
         }
         else {
            if (rtt != -1) fatal("return value expected");
         }
         if (!deadzone) ++rtf; // signal a return statement exists
         *--n = (int) a; *--n = Return;
      }
      if (tk != ';') fatal("semicolon expected");
      next();
      return;
   case Goto:
      next();
      if (tk != Id || (id->type != 0 && id->type != -1)
                || (id->class != Label && id->class != 0))
         fatal("goto expects label");
      if (id < lab || id >= labt) { // move labels to separate area
         if (id != symlh || (labt - lab) == MAX_LABEL)
            fatal("label problem");
         memcpy(idl, id->name, i = idp - id->name); idp = id->name;
         memcpy(id = labt++, symlh++, sizeof (struct ident_s));
         id->name = idl; idl += i;
      }
      id->type = -1; // hack for id->class deficiency
      *--n = (int) id; *--n = Goto; next();
      if (tk != ';') fatal("semicolon expected");
      next();
      return;
   case Inln:
      if (ctx == Loc) goto inln_func_expr; // assume void func call
      next(); inln_func = 1;
      if (ctx != Glo || ((tk < Char || tk > Union) && tk != TypeId))
         fatal("bad inline scope"); // func def constraints
      goto process_inln;
   default:
      expr(Assign);
      while (tk == ',' && ctx == Loc) {
         int *t;
         next(); t = n;  expr(Assign);
         if (t != n) { *--n = (int) t; *--n = '{'; }
      }
      if (tk != ';' && tk != ',') fatal("semicolon expected");
      next();
   }
}

void die(char *msg) { printf("%s\n", msg); exit(-1); }

int reloc_imm(int offset) { return (((offset) - 8) >> 2) & 0x00ffffff; }
int reloc_bl(int offset) { return 0xeb000000 | reloc_imm(offset); }

int icnst[512], nicnst;

int addcnst(int val)
{
   int i;
   for (i=0; i<nicnst; ++i) {
      if (icnst[i] == val) break;
   }
   if (i == nicnst) {
      icnst[nicnst++] = val;
   }
   return i; // byte offset
}

int *codegen(int *jitmem, int *jitmap)
{
   int i, ii, jj, kk, tmp, c, ni, nf, sz;
   int *je, *tje;    // current position in emitted native code
   int *immloc, *immlocv, *il, *ill, *ivv;
   int *rMap;
   nicnst = 0;

   immloc = il = (int *) malloc(1024 * sizeof(int));
   int *iv = (int *) malloc(1024 * sizeof(int));
   immlocv = iv;
   int *imm0 = 0;
   int *immf0 = 0;

   // first pass: emit native code
   int *pc = text + 1; je = jitmem; line = 0;
   while (pc <= e) {
      i = *pc;
      // Store mapping from IR index to native instruction buffer location
      // "pc - text" gets the index of IR.
      // "je" points to native instruction buffer's current location.
      if (peephole && i == ENT) {
         // align on 16 byte boundary
         while((int)je & 0x0f) *je++ = 0xe1a00000; // mov r0, r0
         // add space for 16 frame register constants
         for (ii=0; ii<16; ++ii) *je++ = 0xe1a00000; // mov r0, r0
      }
      jitmap[pc++ - text] = (int) je;
      switch (i) {
      case LEA:
         tmp = *pc++;
         if (tmp >= 64 || tmp <= -64) {
            if (!imm0) imm0 = je;
            *il++ = (int) (je++); *iv++ = addcnst(tmp * 4);
            *je++ = 0xe08b0000;   // add r0, fp, r0
         }
         else if (tmp >= 0)
            *je++ = 0xe28b0000 | tmp * 4;     // add r0, fp, #(tmp)
         else
            *je++ = 0xe24b0000 | (-tmp) * 4;  // sub r0, fp, #(tmp)
         break;
      case IMM:
         tmp = *pc++;
         if (0 <= tmp && tmp < 256)
            *je++ = 0xe3a00000 + tmp;         // mov r0, #tmp
         else if (-256 <= tmp && tmp < 0)
            *je++ = 0xe3e00000 + -(tmp+1);    // mvn r0, #tmp
         else {
             if (!imm0) imm0 = je;
             *il++ = (int) (je++); *iv++ = addcnst(tmp);
         }
         break;
      case IMMF:
         tmp = (int) *pc++;
         if (tmp == 0) tmp = 1; // special handling for FP 0.0
         if (!imm0) imm0 = je; if (!immf0) immf0 = je;
         *il++ = (int) je++ + 2; *iv++ = addcnst(tmp);
         break;
      case JMP:
      case JSR:
         pc++; je++; // postponed till second pass
         break;
      case BZ:
      case BNZ:
         *je++ = 0xe3500000; pc++; je++;      // cmp r0, #0
         break;
      case ENT:
         *je++ = 0xe92d4800; *je++ = 0xe28db000; // push {fp,lr}; add fp, sp, #0
         ii = c = 0; tmp = 4 * (*pc++);
         while (tmp >= 255) { c |= tmp & 3; tmp >>= 2; ++ii; }
         tmp += (c ? 1 : 0); if ((tmp << (2*ii)) >= 32768 || tmp < 0) {
            printf("jit: ENT %d out of bounds\n", tmp << (2*ii)); exit(6);
         } // sub  sp, sp, #tmp (scaled)
         if (tmp) *je++ = 0xe24dd000 | (((16-ii) & 0xf) << 8) | tmp;
         if (peephole) { // reserve space for frame registers
            for (ii=0; ii<48; ++ii) *je++ = 0xe1a00000; // mov r0, r0
         }
         break;
      case ADJ:
         if (*pc & 0x3f)
            *je++ = 0xe28dd000 + ( *pc++ & 0x3f) * 4; // add sp, sp, #(tmp * 4)
         break;
      case LEV:
         *je++ = 0xe28bd000; *je++ = 0xe8bd8800; // add sp, fp, #0; pop {fp, pc}
         break;
      case PSH:
         *je++ = 0xe52d0004;                     // push {r0}
         break;
      case PSHF:
         *je++ = 0xed2d0a01;                     // push {s0}
         break;
      case LC:
         *je++ = 0xe5d00000; if (signed_char)  *je++ = 0xe6af0070; // ldrb r0, [r0]
         break;
      case LI:
         *je++ = 0xe5900000;                     // ldr r0, [r0]
         break;
      case LF:
         *je++ = 0xed900a00;                     // vldr s0, [r0]
         break;
      case SC:
         *je++ = 0xe49d1004; *je++ = 0xe5c10000; // pop {r1}; strb r0, [r1]
         break;
      case SI:
         *je++ = 0xe49d1004; *je++ = 0xe5810000; // pop {r1}; str r0, [r1]
         break;
      case SF:
         *je++ = 0xe49d1004; *je++ = 0xed810a00; // pop {r1}; vstr s0, [r1]
         break;
      case OR:
         *je++ = 0xe49d1004; *je++ = 0xe1810000; // pop {r1}; orr r0, r1, r0
         break;
      case XOR:
         *je++ = 0xe49d1004; *je++ = 0xe0210000; // pop {r1}; eor r0, r1, r0
         break;
      case AND:
         *je++ = 0xe49d1004; *je++ = 0xe0010000; // pop {r1}; and r0, r1, r0
         break;
      case SHL:
         *je++ = 0xe49d1004; *je++ = 0xe1a00011; // pop {r1}; lsl r0, r1, r0
         break;
      case SHR:
         *je++ = 0xe49d1004; *je++ = 0xe1a00051; // pop {r1}; asr r0, r1, r0
         break;
      case ADD:
         *je++ = 0xe49d1004; *je++ = 0xe0810000; // pop {r1}; add r0, r1, r0
         break;
      case SUB:
         *je++ = 0xe49d1004; *je++ = 0xe0410000; // pop {r1}; sub r0, r1, r0
         break;
      case MUL:
         *je++ = 0xe49d1004; *je++ = 0xe0000091; // pop {r1}; mul r0, r1, r0
         break;
      case DIV:
      case MOD:
         if (peephole) *je++ = 0xe1a01001;      // mov r1, r1
         *je++ = 0xe52d0004;                    // push {r0}
         int ti = ef_getidx((i == DIV) ? "__aeabi_idiv" : "__aeabi_idivmod");
         tmp = ef_getaddr(ti);
         if (peephole) *je++ = 0xe1a01001;      // mov r1, r1
         *je++ = 0xe49d0004 | (1 << 12);        // pop r1
         if (peephole) *je++ = 0xe1a01001;      // mov r1, r1
         *je++ = 0xe49d0004 | (0 << 12);        // pop r0
         if (peephole) *je++ = 0xe1a01001;      // mov r1, r1
         *je++ = 0xe28fe000;                    // add lr, pc, #0
         if (!imm0) imm0 = je; *il++ = (int) je++ + 1; *iv++ = addcnst(tmp);
         // ARM EABI modulo helper function produces quotient in r0
         // and the remainder in r1.
         if (i == MOD) {
            if (peephole) *je++ = 0xe1a01001;   // mov r1, r1
            *je++ = 0xe1a00001;                 // mov r0, r1
         }
         break;
      case ADDF:
         *je++ = 0xecfd0a01; *je++ = 0xee300a80; // pop {s1}; add s0, s1, s0
         break;
      case SUBF:
         *je++ = 0xecfd0a01; *je++ = 0xee300ac0; // pop {s1}; sub s0, s1, s0
         break;
      case MULF:
         *je++ = 0xecfd0a01; *je++ = 0xee200a80; // pop {s1}; mul s0, s1, s0
         break;
      case DIVF:
         *je++ = 0xecfd0a01; *je++ = 0xee800a80; // pop {s1}; div s0, s1, s0
         break;
      case FTOI:
         *je++ = 0xeefd0a40; *je++ = 0xee100a90; // ftosis s1, s0; fmrs r0, s1
         break;
      case ITOF:
         *je++ = 0xee000a90; *je++ = 0xeeb80ae0; // frms s1, r0; fsitos s0, s1
         break;
      case SYSC:
         if (pc[1] != ADJ) die("codegen: no ADJ after native proc");
         if ((pc[2] & 0x3f) > 10) die("codegen: no support for 11+ arguments");
         c = pc[2]; ii = c & 0x3f; c >>= 6;
         nf = c & 0x3f; ni = ii - nf; c >>= 6;
         tmp = ef_getaddr(*pc);  // look up address from ef index

         // Handle ridiculous printf() varargs ABI inline
         int isPrtf = nf && isPrintf(ef_cache[*pc]->name);
         if (isPrtf) {
            if (ii == 0) die("printf() has no arguments");
            jj = ii - 1; sz = 0; rMap = (int *) malloc(ii*sizeof(int));
            do {
               if (c & (1 << (ii-1-jj))) { // float (adjust as though double)
                  sz = sz + (sz & 1);
                  rMap[jj] = sz;
                  sz = sz + 2;
               }
               else {
                  rMap[jj] = sz;
                  sz = sz + 1;
               }
               --jj;
            } while (jj >= 0);
            sz = sz + (sz & 1);
            if (sz > 4) *je++ = 0xe24dd000 | (sz - 4)*4; // sub sp, sp, #off
            jj = 0; // in case arguments are all in regs
            if (sz > 4) { // set up stack arguments
               jj = ii - 1;
               do {
                  if (rMap[jj] == 4)
                     break;
                  --jj;
               } while (jj >= 0);
               kk = jj + 1; // number of arguments to copy
               for (jj = 0; jj < kk; ++jj) {
                  if (c & (1 << (ii-1-jj))) { // float
                     // vldr s1, [sp, #(sz + jj*4)]
                     // fcvtds d0, s1
                     // vstr d0,[sp, #rMap[jj]-4]
                     *je++ = 0xeddd0a00 | (jj + (sz - 4));
                     *je++ = 0xeeb70ae0;
                     *je++ = 0xed8d0b00 | (rMap[jj]-4);
                  }
                  else { // int
                     // ldr r0, [sp, #(sz + jj*4)]
                     // str r0, [sp, #rMap[jj]-4]
                     *je++ = 0xe59d0000 | ((sz - 4) + jj)*4;
                     *je++ = 0xe58d0000 | (rMap[jj]*4 - 16);
                  }
               }
            }
            for(; jj < ii; ++jj) { // handle values in regs
               if (c & (1 << (ii-1-jj))) { // float
                  // vldr s"rMap[jj]+1", [sp, #(sz + jj*4)]
                  // fcvtds d"rMap[jj]/2", s"rMap[jj]+1"
                  // vmov r"rMap[jj]", r"rMap[jj]+1", d"rMap[jj]/2"
                  *je++ = 0xeddd0a00 | (rMap[jj] << 11) | (jj + (sz - 4));
                  *je++ = 0xeeb70ae0 | (rMap[jj] << 11) | (rMap[jj] >> 1);
                  if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
                  *je++ = 0xec500b10 | (rMap[jj] << 12) |
                          ((rMap[jj] + 1) << 16) | (rMap[jj] >> 1);
               }
               else { // int
                  if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
                  // ldr r"rMap[jj]", [sp, #(sz + jj*4)]
                  *je++ = 0xe59d0000 | (rMap[jj] << 12) | ((sz - 4) + jj)*4;
               }
            }
            ++pc; // point at ADJ instruction
         }
         else {
            pc = pc + 3; kk = ni; // skip ADJ instruction
            for (jj = 0; jj < ii; ++jj) {
               if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
               if (c & (1 << (ii-1-jj))) { // vpop {nf}
                  --nf;
                  *je++ = 0xecbd0a01 | ((nf & 1) << 22) | ((nf & 0xe) << 11);
               }
               else // pop {ni}
                  *je++ = 0xe49d0004 | (--ni << 12); // pop {ni}
            }
            if ((ni = kk) > 4) {
               if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
               *je++ = 0xe92d03f0; // push [r4-r9]
            }
         }
         if (peephole) *je++ = 0xe1a01001;     // mov r1, r1
         *je++ = 0xe28fe000;                   // add lr, pc, #0
         if (!imm0) imm0 = je; *il++ = (int) je++ + 1; *iv++ = addcnst(tmp);
         if (isPrtf) {
            if (sz > 4) *je++ = 0xe28dd000 | (sz - 4)*4; // add sp, sp, #off
            free(rMap);
         }
         else {
            if (ni > 4) {
               if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
               *je++ = 0xe28dd018;                // add sp, sp, #24
            }
         }
         break;
      case CLCA:
         *je++ = 0xe59d0004; *je++ = 0xe59d1000; // ldr r0, [sp, #4]
                                                 // ldr r1, [sp]
         *je++ = 0xe3a0780f; *je++ = 0xe2877002; // mov r7, #0xf0000
                                                 // add r7, r7, #2
         *je++ = 0xe3a02000; *je++ = 0xef000000; // mov r2, #0
                                                 // svc 0
         break;
      case FNEG: *je++ = 0xeeb10a40; break;      // fnegs  s0, s0
      case FABS: *je++ = 0xeeb00ac0; break;      // fabss  s0, s0
      case SQRT: *je++ = 0xeeb10ac0; break;      // fsqrts s0, s0
      case VENT:
         if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
         *je++ = 0xe08d0000; // add r0, sp, r0
         if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
         *je++ = 0xe3100004; // tst r0, #4   -- lower 2 bits always 0
         if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
         *je++ = 0x152dd004; // pushne {sp}
         break;
      case VLEV: // Note: r0 contains return value
         if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
         *je++ = 0xe59d1000; // ldr r1, [sp]
         if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
         *je++ = 0xe2411004; // sub r1, r1, #4
         if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
         *je++ = 0xe151000d; // cmp r1, sp
         if (peephole) *je++ = 0xe1a01001;  // mov r1, r1
         *je++ = 0x049d1004; // popeq {r1}
         break;
      case PHD:  *je++ = 0xe1a01001; break;      // mov r1, r1
      case PHF:  *je++ = 0xe1a0b00b; break;      // mov fp, fp
      case PHR0: *je++ = 0xe1a0d00d; break;      // mov sp, sp
      default:
         if ((EQ <= i && i <= LE) || (EQF <= i && i <= LEF)) {
            if (EQ <= i && i <= LE) {
               *je++ = 0xe49d1004; *je++ = 0xe1510000; // pop {r1}; cmp r1, r0
            }
            else {
               *je++ = 0xecfd0a01; *je++ = 0xeef40ac0; // pop {s1}; vcmpe s1, s0
               *je++ = 0xeef1fa10; i -= (EQF - EQ);    // vmrs APSR_nzcv, fpscr
               if (*pc == FTOI) *pc = PHR0;
            }
            // moveq r0, #0; movne r0, #0
            if (i <= NE) { je[0] = 0x03a00000; je[1] = 0x13a00000; }
            // movlt r0, #0; movge   r0, #0
            else if (i <= LT) { je[0] = 0xb3a00000; je[1] = 0xa3a00000; }
            // movgt r0, #0; movle r0, #0
            else { je[0] = 0xc3a00000; je[1] = 0xd3a00000; }
            if (i == EQ || i == LT || i == GT)
               je[0] = je[0] | (btrue ? 0x400000 : 1); // use mvn if btrue
            else
               je[1] = je[1] | (btrue ? 0x400000 : 1);
            je += 2;
            break;
         } else {
            printf("code generation failed for %d!\n", i);
            free(iv);
            return 0;
         }
      }

      int genpool = 0;
      if (imm0) {
         if ((i == LEV && (pc == (e+1) || *pc == ENT)) ||
            (i == JMP && // start looking for opportunities
             ((imm0 && je > imm0 + 768) || (immf0 && je > immf0 + 128))))
            genpool = 1;
         else if ( je > imm0 + 896 || // pad for optimizer
                   (immf0 && je > immf0 + 192) ) {
            tje = je - 1;
            if (*tje != 0xe1a01001 &&    // NOP : mov r1, r1
                *tje != 0xe1a0b00b &&    // PHR0: mov r13, r13
                (*tje & 0x000f0000) != 0x000f0000 && // pc-relative mem op
                (*tje & 0xffb00f00) != 0xed900a00 && // vldr
                (*tje & 0xfff00ff0) != 0xe0000090 && // mul
                (*tje & 0xf0000000) == 0xe0000000) { // conditional or branch
               tje = je++; genpool = 2;
            }
         }
      }
      if (genpool) {
         ill = immloc;
         ivv = immlocv;
         *iv = 0;
         // create cnst pool
         for (ii = 0; ii<nicnst; ++ii) {
            if (icnst[ii] == 1) icnst[ii] = 0; // FP 0.0
            je[ii] = icnst[ii];
         }
         while (ill < il) {
            tmp = *ill++;
            if ((int) (je + *ivv) > tmp + 4096 + 8)
               die("codegen: can't reach the pool");
            if (tmp & 1) {
               --tmp;
               // ldr pc, [pc, #..]
               *((int *) tmp) = 0xe59ff000 | ((int) (je + *ivv) - tmp - 8);
            } else if (tmp & 2) {
               tmp -= 2;
               if ((int) (je + *ivv) > (tmp + 255*4 + 8))
                  die("codegen: float constant too far");
               // vldr s0, [pc, #..]
               *((int *)tmp) = 0xed9f0a00 | (((int) (je + *ivv) - tmp - 8) >> 2);
            } else {
               // ldr r0, [pc, #..]
               *(int *) tmp = 0xe59f0000 | ((int) (je + *ivv) - tmp - 8);
            }
            ++ivv;
         }
         je += nicnst;
         if (genpool == 2) { // jump past the pool
            tmp = ((int) je - (int) tje - 8) >> 2;
            *tje = 0xea000000 | (tmp & 0x00ffffff); // b #(je)
         }
         imm0 = immf0 = 0; genpool = 0;
         iv = immlocv; il = immloc; nicnst = 0;
      }
   }
   if (il > immloc) die("codegen: not terminated by a LEV");
   tje = je;

   // second pass
   pc = text + 1; // Point instruction pointer "pc" to the first instruction.
   while (pc <= e) { // While instruction end is not met.
      // Get the IR's corresponding native instruction buffer address.
      je = (int *) jitmap[pc - text];
      i = *pc++; // Get current instruction
      // If the instruction is one of the jumps.
      if (i >= JMP && i <= BNZ) {
         switch (i) {
         case JMP: *je = 0xea000000;   break; // b #(tmp)
         case JSR: *je = 0xeb000000;   break; // bl #(tmp)
         case BZ:  *++je = 0x0a000000; break; // beq #(tmp)
         case BNZ: *++je = 0x1a000000; break; // bne #(tmp)
         }
         tmp = *pc++;
         if (i == JSR) {
            struct ident_s *t = (struct ident_s *) tmp;
            tmp = t->val;
         }
         *je = (*je | reloc_imm(jitmap[(tmp - (int) text) >> 2] - (int) je));
      }
      // If the instruction has operand, increment instruction pointer to
      // skip he operand.
      else if (i <= ADJ || i == SYSC) { ++pc; }
   }
   free(iv); free(immloc);
   return tje;
}

enum {
   _PROT_EXEC = 4, _PROT_READ = 1, _PROT_WRITE = 2,
   _MAP_PRIVATE = 2, _MAP_ANON = 32
};

int jit(int poolsz, int *main, int argc, char **argv)
{
   char *jitmem;  // executable memory for JIT-compiled native code
   int retval;
   if (src) return 0; // skip for IR listing

   // setup JIT memory
   if (!(jitmem = (char *) mmap(0, poolsz,
                                _PROT_EXEC | _PROT_READ | _PROT_WRITE,
                                _MAP_PRIVATE | _MAP_ANON, -1, 0))) {
      printf("could not mmap(%d) jit executable memory\n", poolsz);
      return -1;
   }
   int *jitmap = (int *) (jitmem + (poolsz >> 1));
   int *je = (int *) jitmem;
   *je++ = (int) &retval;
   *je++ = argc;
   *je++ = (int) argv;
   int *_start = je;
   *je++ = 0xe92d5ff0;      // push    {r4-r12, lr}
   *je++ = 0xe51f0014;      // ldr     r0, [pc, #-20] ; argc
   *je++ = 0xe51f1014;      // ldr     r1, [pc, #-20] ; argv
   *je++ = 0xe52d0004;      // push    {r0}
   *je++ = 0xe52d1004;      // push    {r1}
   int *tje = je++;         // bl      jitmain
   *je++ = 0xe51f502c;      // ldr     r5, [pc, #-44] ; retval
   *je++ = 0xe5850000;      // str     r0, [r5]
   *je++ = 0xe28dd008;      // add     sp, sp, #8
   *je++ = 0xe8bd9ff0;      // pop     {r4-r12, pc}
   if (!(je = codegen(je, jitmap))) return 1;
   if (je >= jitmap) die("jitmem too small");
   *tje = reloc_bl(jitmap[main - text] - (int) tje);

#ifdef SQUINT_SO
   if (peephole) squint_opt((int *)jitmem, je);
#endif

   // hack to jump into specific function pointer
   __clear_cache(jitmem, je);
   int *res = (int *) bsearch(&sym, sym, 1, 1, (void *) _start);
   if (((int *) 0) != res) return 0; return -1; // make compiler happy
}

int ELF32_ST_INFO(int b, int t) { return (b << 4) + (t & 0xf); }
enum {
   EHDR_SIZE = 52, ET_EXEC = 2, EM_ARM = 40,
   PHDR_ENT_SIZE = 32, SHDR_ENT_SIZE = 40,
   SYM_ENT_SIZE = 16, REL_ENT_SIZE = 8, PLT_ENT_SIZE = 12,
   DYN_ENT_SIZE = 8
};

struct Elf32_Shdr {
   int sh_name;      // [Elf32_Word] Section name (index into string table)
   int sh_type;      // [Elf32_Word] Section type (SHT_*)
   int sh_flags;     // [Elf32_Word] Section flags (SHF_*)
   int sh_addr;      // [Elf32_Addr] Address where section is to be loaded
   int sh_offset;    // [Elf32_Off] File offset of section data, in bytes
   int sh_size;      // [Elf32_Word] Size of section, in bytes
   int sh_link;      // [Elf32_Word] Section type-specific header table
                     //              index link
   int sh_info;      // [Elf32_Word] Section type-specific extra information
   int sh_addralign; // [Elf32_Word] Section address alignment
   int sh_entsize;   // [Elf32_Word] Size of records contained within section
};

enum {
   // Special section indices
   SHN_UNDEF        = 0,  // Undefined, missing, irrelevant, or meaningless

   // Section types
   SHT_NULL         = 0,  // No associated section (inactive entry)
   SHT_PROGBITS     = 1,  // Program-defined contents
   SHT_STRTAB       = 3,  // String table
   SHT_DYNAMIC      = 6,  // Information for dynamic linking
   SHT_REL          = 9,  // Relocation entries; no explicit addends
   SHT_DYNSYM       = 11, // Symbol table

   // Section flags
   SHF_WRITE = 0x1,
   SHF_ALLOC = 0x2,
   SHF_EXECINSTR = 0x4,
};

// Symbol table entries for ELF32
struct Elf32_Sym {
   int st_name;  // [Elf32_Word] Symbol name (index into string table)
   int st_value; // [Elf32_Addr] Value or address associated with the symbol
   int st_size;  // [Elf32_Word] Size of the symbol
   char st_info; // [unsigned] Symbol's type and binding attributes
   char st_other;// [unsigned] Must be zero; reserved
   char st_shndx, st_shndx_1, st_shndx_2, st_shndx_3; // [Elf32_Half]
                 // Which section (header table index) it's defined
};

enum {
   // Symbol bindings
   STB_LOCAL  = 0,  /* Local symbol, not visible outside obj file
                                containing def */
   STB_GLOBAL = 1,  /* Global symbol, visible to all object files
                               being combined */

   // Symbol types
   STT_NOTYPE  = 0,   // Symbol's type is not specified
   STT_FUNC    = 2,   // Symbol is executable code (function, etc.)

   // Symbol number
   STN_UNDEF = 0
};

// Program header for ELF32
struct Elf32_Phdr {
   int p_type;   // [Elf32_Word] Type of segment
   int p_offset; // [Elf32_Off] File offset where segment is located, in bytes
   int p_vaddr;  // [Elf32_Addr] Virtual address of beginning of segment
   int p_paddr;  // [Elf32_Addr] Physical address of beginning of segment
                 //              (OS-specific)
   int p_filesz; // [Elf32_Word] Number of bytes in file image of segment
                 //              (may be zero)
   int p_memsz;  // [Elf32_Word] Number of bytes in mem image of segment
                 //              (may be zero)
   int p_flags;  // [Elf32_Word] Segment flags
   int p_align;  // [Elf32_Word] Segment alignment constraint
};

// Segment types
enum {
   PT_NULL    = 0, // Unused segment
   PT_LOAD    = 1, // Loadable segment
   PT_DYNAMIC = 2, // Dynamic linking information
   PT_INTERP  = 3, // Interpreter pathname

   // Segment flag bits
   PF_X       = 1,         // Execute
   PF_W       = 2,         // Write
   PF_R       = 4,         // Read
};

int phdr_idx, shdr_idx, sym_idx;

int gen_phdr(char *ptr, int type, int offset, int addr, int size,
          int flag, int align)
{
   struct Elf32_Phdr *phdr = (struct Elf32_Phdr *) ptr;
   phdr->p_type =  type;
   phdr->p_offset = offset;
   phdr->p_vaddr = addr;
   phdr->p_paddr = addr;
   phdr->p_filesz = size;
   phdr->p_memsz = size;
   phdr->p_flags = flag;
   phdr->p_align = align;
   return phdr_idx++;
}

int gen_shdr(char *ptr, int type, int name, int offset, int addr,
          int size, int link, int info,
          int flag, int align, int entsize)
{
   struct Elf32_Shdr *shdr = (struct Elf32_Shdr *) ptr;
   shdr->sh_name = name;      shdr->sh_type = type;
   shdr->sh_addr = addr;      shdr->sh_offset = offset;
   shdr->sh_size = size;      shdr->sh_link = link;
   shdr->sh_info = info;      shdr->sh_flags = flag;
   shdr->sh_addralign = align; shdr->sh_entsize = entsize;
   return shdr_idx++;
}

int gen_sym(char *ptr, int name, char info,
         int shndx, int size, int value)
{
   struct Elf32_Sym *s = (struct Elf32_Sym *) ptr;
   s->st_name = name;
   s->st_info = info;
   s->st_other = 0;
   // s->st_shndx = shndx;
   memcpy(&(s->st_shndx), (char *) &shndx, 2);
   s->st_value = value;
   s->st_size = size;
   return sym_idx++;
}

int append_func_sym(char **sdata, int name)
{
   int idx = gen_sym(*sdata, name, ELF32_ST_INFO(STB_GLOBAL, STT_FUNC), 0, 0, 0);
   *sdata += SYM_ENT_SIZE;
   return idx;
}

// shdr names which start with 'S'
enum {
   SNONE = 0, SSTAB, STEXT, SDATA, SDYNS, SDYNM, SDYNC,
   SINTP, SREL, SPLT, SGOT
};

enum {
   PAGE_SIZE = 0x1000, PHDR_NUM = 4, SHDR_NUM = 11,
   DYN_NUM = 16
};

void elf32_init(int poolsz)
{
   int i;
   freebuf = (char *) malloc(poolsz);
   char *o = (char *) (((int) freebuf + PAGE_SIZE - 1)  & -PAGE_SIZE);
   /* We must assign the plt_func_addr[x] a non-zero value, and also,
    * plt_func_addr[i] and plt_func_addr[i-1] has an offset of 16
    * (4 instruction * 4 bytes), so the first codegen and second codegen
    * have consistent code_size. Dummy address at this point.
    */
   plt_func_addr = (char **) malloc(sizeof(char *) * SMALL_TBL_SZ);
   for (i = 0; i < SMALL_TBL_SZ; ++i)
      plt_func_addr[i] = o + i * 16;

   ef_getidx("__libc_start_main"); // slot 0 of external func cache
}

int elf32(int poolsz, int *main, int elf_fd)
{
   int i;
   char *freecode;
   char *code = freecode = (char *) malloc(poolsz);
   char *buf = freebuf;
   int *jitmap = (int *) (code + (poolsz >> 1));
   // memset(buf, 0, poolsz); // not strictly necessary
   char *o = buf = (char *) (((int) buf + PAGE_SIZE - 1) & -PAGE_SIZE);
   code = (char *) (((int) code + PAGE_SIZE - 1) & -PAGE_SIZE);

   phdr_idx = 0;
   shdr_idx = 0;
   sym_idx = 0;

   /* Run __libc_start_main() and pass main trampoline.
    *
    * Note: The function prototype of __libc_start_main() is:
    *
    *     int __libc_start_main(int (*main)(int, char**, char**),
    *                      int argc, char **argv,
    *                      int (*init)(int, char**, char**),
    *                      void (*fini)(void),
    *                      void (*rtld_fini)(void),
    *                      void *stack_end);
    *
    * Usually, we should pass __libc_csu_init as init and __libc_csu_fini
    * as fini; however, we will need a interp to link the non-shared part
    * of libc.  It sounds too complex.  To keep this compiler simple,
    * let's simply pass NULL pointer.
    */
   int *stub_end = (int *) code;

   *stub_end++ = 0xe3a0b000;  // mov   fp, #0  @ initialize frame pointer
   *stub_end++ = 0xe3a0e000;  // mov   lr, #0  @ initialize link register
   *stub_end++ = 0xe49d1004;  // pop   {r1}    @ get argc
   *stub_end++ = 0xe1a0200d;  // mov   r2, sp  @ get argv
   *stub_end++ = 0xe52d2004;  // push  {r2}    @ setup stack end
   *stub_end++ = 0xe52d0004;  // push  {r0}    @ setup rtld_fini
   *stub_end++ = 0xe3a0c000;  // mov   ip, #0  @ FIXME: __libc_csu_fini()
   *stub_end++ = 0xe52dc004;  // push  {ip}    @ setup fini
   *stub_end++ = 0xe28f0010;  // add   r0, pc, #16  @ load main trampoline
   *stub_end++ = 0xe3a03000;  // mov   r3, #0  @ FIXME: __libc_csu_init()
   *stub_end++ = 0xebfffffe;  // bl    __libc_start_main  @ Need relocation

   // Return 127 if __libc_start_main() returns (which should not.)
   *stub_end++ = 0xe3a0007f;  // mov   r0, #127
   *stub_end++ = 0xe3a07001;  // mov   r7, #1
   *stub_end++ = 0xef000000;  // svc   0x00000000

   // main() trampoline: convert ARM AAPCS calling convention to ours.
   *stub_end++ = 0xe92d5ff0;  // push  {r4-r12, lr}
   *stub_end++ = 0xe52d0004;  // push  {r0}
   *stub_end++ = 0xe52d1004;  // push  {r1}
   *stub_end++ = 0xebfffffe;  // bl    0 <main>  @ Need relocation
   *stub_end++ = 0xe28dd008;  // add   sp, sp, #8
   *stub_end++ = 0xe8bd9ff0;  // pop   {r4-r12, pc}

   int start_stub_size = (char *) stub_end - code;

   // Compile and generate the code.
   char *je = (char *) codegen((int *) (code + start_stub_size), jitmap);
   if (!je) return 1;
   if ((int *) je >= jitmap) die("elf32: jitmem too small");

#ifdef SQUINT_SO
   if (peephole) squint_opt((int *)code, (int *) je);
#endif

   // elf32_hdr
   *o++ = 0x7f; *o++ = 'E'; *o++ = 'L'; *o++ = 'F';
   *o++ = 1;    *o++ = 1;   *o++ = 1;   *o++ = 0;
   o += 8;
   *o++ = ET_EXEC;        *o++ = 0; // e_type
   *o++ = EM_ARM;         *o++ = 0; // e_machine
   *(int *) o = 1;          o += 4;
   char *entry = o;         o += 4; // e_entry
   *(int *) o = EHDR_SIZE;  o += 4; // e_phoff
   char *e_shoff = o;       o += 4; // e_shoff
   *(int *) o = 0x5000400;  o += 4; // e_flags
   *o++ = EHDR_SIZE; *o++ = 0;
   // e_phentsize & e_phnum
   *o++ = PHDR_ENT_SIZE; *o++ = 0; *o++ = PHDR_NUM; *o++ = 0;
   // e_shentsize & e_shnum
   *o++ = SHDR_ENT_SIZE; *o++ = 0; *o++ = SHDR_NUM; *o++ = 0;
   *o++ =  1; *o++ = 0;

   int phdr_size = PHDR_ENT_SIZE * PHDR_NUM;
   char *phdr = o; o += phdr_size;

   // .text
   int code_off = o - buf;
   int code_size = je - code;
   char *code_addr = o;
   o += code_size;

   // .rel.plt (embedded in PT_LOAD of text)
   int rel_size = REL_ENT_SIZE * ef_count;
   int rel_off = code_off + code_size;
   char *rel_addr = code_addr + code_size;
   o += rel_size;

   // .plt (embedded in PT_LOAD of text)
   // 20 is the size of .plt entry code to .got
   int plt_size = 20 + PLT_ENT_SIZE * ef_count;
   int plt_off = rel_off + rel_size;
   char *plt_addr = rel_addr + rel_size;
   o += plt_size;

   memcpy(code_addr, code,  code_size);
   *(int *) entry = (int) code_addr;

   // .data
   char *_data_end = data;
   // Use load_bias to align offset and v_addr, the elf loader
   // needs PAGE_SIZE align to do mmap().
   int load_bias = PAGE_SIZE + ((int) _data & (PAGE_SIZE - 1))
                               - ((o - buf) & (PAGE_SIZE - 1));
   o += load_bias;
   char *dseg = o;

   // rwdata (embedded in PT_LOAD of data)
   // rwdata is all the data (R/O and R/W) in source code,
   // e.g, the variable with initial value and all the string.
   int rwdata_off = dseg - buf;
   int rwdata_size = _data_end - _data;
   o += rwdata_size;

   // .dynamic (embedded in PT_LOAD of data)
   char *pt_dyn = data;
   int pt_dyn_size = DYN_NUM * DYN_ENT_SIZE;
   int pt_dyn_off = rwdata_off + rwdata_size; data += pt_dyn_size;
   o += pt_dyn_size;

   // .interp (embedded in PT_LOAD of data)
   char *interp_str = "/lib/ld-linux-armhf.so.3";
   int interp_str_size = 25; // strlen(interp_str) + 1
   char *interp = data;
   memcpy(interp, interp_str, interp_str_size);
   int interp_off = pt_dyn_off + pt_dyn_size; data += interp_str_size;
   o += interp_str_size;

   // .shstrtab (embedded in PT_LOAD of data)
   char *shstrtab_addr = data;
   int shstrtab_off = interp_off + interp_str_size;
   int shstrtab_size = 0;

   int *shdr_names = (int *) malloc(sizeof(int) * SHDR_NUM);
   if (!shdr_names) die("elf32: could not malloc shdr_names table");

   shdr_names[SNONE] = append_strtab(&data, "") - shstrtab_addr;
   shdr_names[SSTAB] = append_strtab(&data, ".shstrtab") - shstrtab_addr;
   shdr_names[STEXT] = append_strtab(&data, ".text") - shstrtab_addr;
   shdr_names[SDATA] = append_strtab(&data, ".data") - shstrtab_addr;
   shdr_names[SDYNS] = append_strtab(&data, ".dynstr") - shstrtab_addr;
   shdr_names[SDYNM] = append_strtab(&data, ".dynsym") - shstrtab_addr;
   shdr_names[SDYNC] = append_strtab(&data, ".dynamic") - shstrtab_addr;
   shdr_names[SINTP] = append_strtab(&data, ".interp") - shstrtab_addr;
   shdr_names[SREL] = append_strtab(&data, ".rel.plt") - shstrtab_addr;
   shdr_names[SPLT] = append_strtab(&data, ".plt") - shstrtab_addr;
   shdr_names[SGOT] = append_strtab(&data, ".got") - shstrtab_addr;
   shstrtab_size = data - shstrtab_addr;
   o += shstrtab_size;

   // .dynstr (embedded in PT_LOAD of data)
   char *dynstr_addr = data;
   int dynstr_off = shstrtab_off + shstrtab_size;
   append_strtab(&data, "");
   char *libc = append_strtab(&data, "libc.so.6");
   char *ldso = append_strtab(&data, "libdl.so.2");
   char *libgcc_s = append_strtab(&data, "libgcc_s.so.1");
   char *libm = append_strtab(&data, "libm.so.6");

   int *func_entries = (int *) malloc(sizeof(int) * ef_count);
   if (!func_entries) die("elf32: could not malloc func_entries table");

   for (i = 0; i < ef_count; ++i)
      func_entries[i] = append_strtab(&data, ef_cache[i]->name) - dynstr_addr;

   int dynstr_size = data - dynstr_addr;
   o += dynstr_size;

   // .dynsym (embedded in PT_LOAD of data)
   char *dynsym_addr = data;
   int dynsym_off = dynstr_off + dynstr_size;
   memset(data, 0, SYM_ENT_SIZE);
   data += SYM_ENT_SIZE;

   for (i = 0; i < ef_count; ++i)
      append_func_sym(&data, func_entries[i]);

   int dynsym_size = SYM_ENT_SIZE * (ef_count + 1);
   o += dynsym_size;

   // .got (embedded in PT_LOAD of data)
   char *got_addr = data;
   int got_off = dynsym_off + dynsym_size;
   *(int *) data = (int) pt_dyn; data += 4;
   data += 4;                 // reserved 2 and 3 entry for interp
   char *to_got_movw = data;  // The address manipulates dynamic
   char *to_got_movt = data;  // linking, plt must jump here.
   data += 4;                 // reserved 2 and 3 entry for interp
   // .got function slot
   char **got_func_slot = (char **) malloc(sizeof(char *) * ef_count);
   for (i = 0; i < ef_count; ++i) {
      got_func_slot[i] = data;
      *(int *) data = (int) plt_addr; data += 4;
   }
   data += 4;  // end with 0x0
   int got_size = (int) data - (int) got_addr;
   o += got_size;

   int dseg_size = o - dseg;

   // .plt -- Now we back to handle .plt after .got was initial
   char *to = plt_addr;
   *(int *) to = 0xe52de004; to += 4; // push {lr}
   // movw r10 addr_to_got
   *(int *) to = 0xe300a000 | (0xfff & (int) (to_got_movw)) |
                   (0xf0000 & ((int) (to_got_movw) << 4));
   to += 4;
   // movt r10 addr_to_got
   *(int *) to = 0xe340a000 | (0xfff & ((int) (to_got_movt) >> 16)) |
                   (0xf0000 & ((int) (to_got_movt) >> 12));
   to += 4;
   *(int *) to = 0xe1a0e00a; to += 4;  // mov lr,r10
   *(int *) to = 0xe59ef000; to += 4;  // ldr pc, [lr]

   // We must preserve ip for code below, dyn link use this as return address
   for (i = 0; i < ef_count; ++i) {
      plt_func_addr[i] = to;
      // movt ip addr_to_got
      *(int *) to = 0xe300c000 | (0xfff & (int) (got_func_slot[i])) |
                      (0xf0000 & ((int) (got_func_slot[i]) << 4));
      to += 4;
      // movw ip addr_to_got
      *(int *) to = 0xe340c000 |
                      (0xfff & ((int) (got_func_slot[i]) >> 16)) |
                      (0xf0000 & ((int) (got_func_slot[i]) >> 12));
      to += 4;
      *(int *) to = 0xe59cf000; to += 4;  // ldr pc, [ip]
   }

   // .rel.plt
   to = rel_addr;
   for (i = 0; i < ef_count; ++i) {
      *(int *) to = (int) got_func_slot[i]; to += 4;
      *(int *) to = 0x16 | ((i + 1) << 8) ; to += 4;
      // 0x16 R_ARM_JUMP_SLOT | .dymstr index << 8
   }

   // Generate program header after we got address, offset and size.
   to = phdr;
   // PT_LOAD for .text
   gen_phdr(to, PT_LOAD, 0, (int) buf,
         EHDR_SIZE + phdr_size + code_size + rel_size + plt_size,
         PF_X | PF_R, PAGE_SIZE);
   to += PHDR_ENT_SIZE;

   // PT_LOAD for .data
   gen_phdr(to, PT_LOAD, rwdata_off, (int) _data,
         dseg_size, PF_W | PF_R, PAGE_SIZE);
   to += PHDR_ENT_SIZE;

   // PT_INTERP for .interp
   gen_phdr(to, PT_INTERP, interp_off, (int) interp,
         interp_str_size , PF_R, 0x1);
   to += PHDR_ENT_SIZE;

   // PT_DYNAMIC for .dynamic
   gen_phdr(to, PT_DYNAMIC, pt_dyn_off, (int) pt_dyn,
         pt_dyn_size , PF_R | PF_W, 0x4);

   // .dynamic (embedded in PT_LOAD of data)
   to = pt_dyn;
   *(int *) to =  5; to += 4; *(int *) to = (int) dynstr_addr;  to += 4;
   *(int *) to = 10; to += 4; *(int *) to = dynstr_size;        to += 4;
   *(int *) to =  6; to += 4; *(int *) to = (int) dynsym_addr;  to += 4;
   *(int *) to = 11; to += 4; *(int *) to = 16;                 to += 4;
   *(int *) to = 17; to += 4; *(int *) to = (int) rel_addr;     to += 4;
   *(int *) to = 18; to += 4; *(int *) to = rel_size;           to += 4;
   *(int *) to = 19; to += 4; *(int *) to = 8;                  to += 4;
   *(int *) to =  3; to += 4; *(int *) to = (int) got_addr;     to += 4;
   *(int *) to =  2; to += 4; *(int *) to = rel_size;           to += 4;
   *(int *) to = 20; to += 4; *(int *) to = 17;                 to += 4;
   *(int *) to = 23; to += 4; *(int *) to = (int) rel_addr;     to += 4;
   *(int *) to =  1; to += 4; *(int *) to = libc - dynstr_addr; to += 4;
   *(int *) to =  1; to += 4; *(int *) to = ldso - dynstr_addr; to += 4;
   *(int *) to =  1; to += 4; *(int *) to = libgcc_s - dynstr_addr; to += 4;
   *(int *) to =  1; to += 4; *(int *) to = libm - dynstr_addr; to += 4;
   *(int *) to =  0;

   /* Generate code again bacause address of .plt function slots must
    * be confirmed before codegen() to make sure the code is correct.
    */
   je = (char *) codegen((int *) (code + start_stub_size), jitmap);
   if (!je) {
      free(func_entries);
      free(shdr_names);
      return 1;
   }
   if ((int *) je >= jitmap) die("elf32: jitmem too small");

#ifdef SQUINT_SO
   if (peephole) squint_opt((int *)code, (int *) je);
#endif

   // Relocate __libc_start_main() and main().
   *((int *) (code + 0x28)) = reloc_bl(plt_func_addr[0] - code_addr - 0x28);
   *((int *) (code + 0x44)) =
      reloc_bl(jitmap[main - text] - (int) code - 0x44);

   // Copy the generated binary.
   memcpy(code_addr, code,  je - code);

   // Generate section header
   *(int *) e_shoff = (int) (o - buf);
   gen_shdr(o, SHT_NULL, shdr_names[SNONE], 0, 0, 0,
          0, 0, 0, 0, 0);
   o += SHDR_ENT_SIZE;

   // sh_shstrtab_idx
   gen_shdr(o, SHT_STRTAB, shdr_names[SSTAB], shstrtab_off, 0,
          shstrtab_size, 0, 0, 0, 1, 0);
   o += SHDR_ENT_SIZE;

   // sh_text_idx
   gen_shdr(o, SHT_PROGBITS, shdr_names[STEXT], code_off, (int) code_addr,
         code_size, 0, 0, SHF_ALLOC | SHF_EXECINSTR, 4, 0);
   o += SHDR_ENT_SIZE;

   // sh_data_idx
   gen_shdr(o, SHT_PROGBITS, shdr_names[SDATA], rwdata_off, (int) _data,
          dseg_size, 0, 0, SHF_ALLOC | SHF_WRITE, 4, 0);
   o += SHDR_ENT_SIZE;

   int sh_dynstr_idx =
   gen_shdr(o, SHT_STRTAB, shdr_names[SDYNS], dynstr_off, (int) dynstr_addr,
          dynstr_size, 0, 0, SHF_ALLOC, 1, 0);
   o += SHDR_ENT_SIZE;

   int sh_dynsym_idx =
   gen_shdr(o, SHT_DYNSYM, shdr_names[SDYNM], dynsym_off, (int) dynsym_addr,
          dynsym_size, sh_dynstr_idx, 1, SHF_ALLOC, 4, 0x10);
   o += SHDR_ENT_SIZE;

   // sh_dynamic_idx
   gen_shdr(o, SHT_DYNAMIC, shdr_names[SDYNC], pt_dyn_off, (int) pt_dyn,
          pt_dyn_size, sh_dynstr_idx, 0, SHF_ALLOC | SHF_WRITE, 4, 0);
   o += SHDR_ENT_SIZE;

   // sh_interp_idx
   gen_shdr(o, SHT_PROGBITS, shdr_names[SINTP], interp_off, (int) interp,
          interp_str_size, 0, 0, SHF_ALLOC, 1, 0);
   o += SHDR_ENT_SIZE;

   // sh_rel_idx
   gen_shdr(o, SHT_REL, shdr_names[SREL], rel_off, (int) rel_addr,
          rel_size, sh_dynsym_idx, 11, SHF_ALLOC | 0x40, 4, 8);
   o += SHDR_ENT_SIZE;

   // sh_plt_idx
   gen_shdr(o, SHT_PROGBITS, shdr_names[SPLT], plt_off, (int) plt_addr,
          plt_size, 0, 0, SHF_ALLOC | SHF_EXECINSTR, 4, 4);
   o += SHDR_ENT_SIZE;

   // sh_got_idx
   gen_shdr(o, SHT_PROGBITS, shdr_names[SGOT], got_off, (int) got_addr,
          got_size, 0, 0, SHF_ALLOC | SHF_WRITE, 4, 4);
   o += SHDR_ENT_SIZE;

   // Copy .data to a part of (o - buf) where _data located.
   memcpy(dseg, _data, dseg_size);
   write(elf_fd, buf, o - buf);

   free(func_entries);
   free(shdr_names);
   free(freebuf);
   free(freecode);
   free(plt_func_addr);
   free(got_func_slot);
   return 0;
}

enum { _O_CREAT = 64, _O_WRONLY = 1 };

int main(int argcc, char **argvv)
{
   int *freed_ast, *ast, argc;
   int elf_fd;
   int fd, i, otk;
   int poolsz = 4 * 1024 * 1024; // arbitrary size
   char **argv;

   labt = lab; // initialize label Ids

   if (!(sym = symk = symgt = (struct ident_s *) malloc(poolsz)))
      die("could not allocate symbol area");
   symlh = symlt = (struct ident_s *) ((int)sym + poolsz);
   syms = (struct ident_s *) ((int)sym + poolsz/2);
   idp = idn = (char *) malloc(256 * 1024); // max space for id names
   idl = idln = (char *) malloc(9 * MAX_LABEL); // space for label names

   // Register keywords in symbol stack. Must match the sequence of enum
   p = "typedef enum char int float struct union "
       "sizeof return goto break continue "
       "if do while for switch case default else inline "
       "void main __clear_cache fnegf fabsf sqrtf";

   // call "next" to create symbol table entry.
   // store the keyword's token type in the symbol table entry's "tk" field.
   for (i = Typedef; i <= Inln; ++i) {
      next(); id->tk = i; id->class = Keyword; // add keywords to symbol table
   }

   next(); id->tk = Char; id->class = Keyword; // handle void type
   symk = symgt; // mark keyword section
   next();
   struct ident_s *idmain = id; id->class = Main; // keep track of main
                                id->ftype[0] = 0;
   next(); id->class = ClearCache; id->type = INT; id->val = CLCA;
   next(); id->class = Fneg; id->type = FLOAT;
           id->val = FNEG; id->ftype[0] = 0x1041;
   next(); id->class = Fabs; id->type = FLOAT;
           id->val = FABS; id->ftype[0] = 0x1041;
   next(); id->class = Sqrt; id->type = FLOAT;
           id->val = SQRT; id->ftype[0] = 0x1041;

   if (!(freedata = _data = data = (char *) malloc(poolsz)))
      printf("could not allocat data area");
   memset(data, 0, poolsz);
   if (!(tsize = (int *) malloc(SMALL_TBL_SZ * sizeof(int))))
      die("could not allocate tsize area");
   memset(tsize,   0, SMALL_TBL_SZ * sizeof(int)); // not strictly necessary
   if (!(freed_ast = ast = (int *) malloc(poolsz)))
      die("could not allocate abstract syntax tree area");
   // memset(ast, 0, poolsz); // not strictly necessary
   ast = (int *) ((int) ast + poolsz); // AST is built as a stack
   n = ast;

   // add primitive types
   tsize[tnew++] = sizeof(char);
   tsize[tnew++] = sizeof(int);
   tsize[tnew++] = sizeof(float);
   tsize[tnew++] = 0;  // reserved for another scalar type

   // create an __MC__ identifier
   p = "__MC__ "; next();
   id->class = Num; id->val = 1; id->type = INT;

   argc = argcc - 1; argv = argvv + 1;
   while (argc > 0 && **argv == '-') {
      if ((*argv)[1] == 's') {
         src = ((*argv)[2] == 'i') ? 2 : 1; --argc; ++argv;
      }
      else if ((*argv)[1] == 'r') {
         single_exit = 1; --argc; ++argv;
      }
      else if (!strcmp(*argv, "-fsigned-char")) {
         signed_char = 1; --argc; ++argv;
      }
      else if ((*argv)[1] == 'O' && (*argv)[2] == 'p') {
         peephole = 1; --argc; ++argv;
      }
      else if ((*argv)[1] == 'm' && (*argv)[2] == 'a') {
         ma = 1 - ma; --argc; ++argv;
      }
      else if ((*argv)[1] == 'o') {
         elf = 1; --argc; ++argv;
         if (argc < 1) die("no output file argument");
         if ((elf_fd = open(*argv, _O_CREAT | _O_WRONLY, 0775)) < 0) {
            printf("could not open(%s)\n", *argv); return -1;
         }
         --argc; ++argv;
      }
      else if ((*argv)[1] == 'D') {
         p = &(*argv)[2]; next();
         if (tk != Id) fatal("bad -D identifier");
         struct ident_s *dd = id; next(); i = 0; otk = Num;
         if (tk == Assign) {
            next();
            expr(Cond);
            if (*n != Num && *n != NumF)
               fatal("bad -D initializer");
            otk = *n; i = n[1]; n += 2;
         }
         dd->class = otk; dd->val = i;
         dd->type = (otk == Num) ? INT : FLOAT;
         --argc; ++argv;
      }
      else if (!strcmp(*argv, "-btrue")) {
         // so that boolean values can be mutiplied by "true"
         btrue = 1; --argc; ++argv;
      }
      else {
         argc = 0; // bad compiler option. Force exit.
      }
   }
   if (argc < 1)
      die("usage: mc [-s] [-Op] [-fsigned-char] [-o object] file");

   if ((fd = open(*argv, 0)) < 0) {
      printf("could not open(%s)\n", *argv); return -1;
   }

   if (!(text = le = e = (char *) malloc(poolsz)))
      die("could not allocate text area");
   if (!(members = (struct member_s **)
                   malloc(SMALL_TBL_SZ * sizeof(struct member_s *))))
      die("could not malloc() members area");
   if (!(ef_cache = (struct ef_s **)
                    malloc(SMALL_TBL_SZ * sizeof(struct ef_s *))))
      die("could not malloc() external function cache");

   // memset(e, 0, poolsz); // not strictly necessary

   memset(members, 0, SMALL_TBL_SZ * sizeof(struct member_s *));

   if (elf) elf32_init(poolsz); // call before source code parsing

   if (!(freep = lp = p = (char *) malloc(poolsz)))
      die("could not allocate source area");
   if ((i = read(fd, p, poolsz - 1)) <= 0)
      die("unable to read from source file");
   p[i] = 0;
   close(fd);

   // real C parser begins here
   // parse the program
   line = 1;
   pplev = 0; pplevt = -1; ppactive = 1;
   next();
   while (tk) {
      stmt(Glo);
      next();
   }

   if (idmain->val == 0) fatal("missing main() function");
   int fdeferr = 0;
   for (id = symk; id < symgt; ++id) { // global ids
      if (id->chain) {
         printf("forward declared function %s() called but not defined.\n",
                id->name);
         fdeferr = 1;
      }
   }
   if (fdeferr) exit(-1);

   int ret = elf ? elf32(poolsz, (int *) idmain->val, elf_fd) :
                   jit(poolsz,   (int *) idmain->val, argc, argv);
   free(freep);
   free(text);
   free(freed_ast);
   free(tsize);
   free(freedata);
   free(idln);
   free(idn);
   free(sym);

   return ret;
}