path: root/codegen.c

#include "chibicc.h"
#include <unistd.h>

#define GP_MAX 6
#define FP_MAX 8

int is_bad_number(double x) {
  return (x != x) || (x == 1./0.) || (-x == 1./0.);
}

/////////// PRINTING
static FILE *CURR_BUFFER,
            // the typedefs at the very beginning
            *TYPE_BUFFER,
            // everything after the typedefs
            *MAIN_BUFFER,
            // code inside a function (after all declarations, which go into
            // the main buffer immediately)
            *CODE_BUFFER;

FILE *BUFFER_STACK[8];
int N_BUFFER_STACK;
static void push_buffer(FILE *which) {
  assert(N_BUFFER_STACK < 8);
  BUFFER_STACK[N_BUFFER_STACK++] = which;
  CURR_BUFFER = which;
}
static void pop_buffer(FILE *which) {
  assert(N_BUFFER_STACK--);
  assert(BUFFER_STACK[N_BUFFER_STACK] == which);
  CURR_BUFFER = BUFFER_STACK[N_BUFFER_STACK - 1];
}
static void flush_buffer(FILE *to_buffer, FILE *from_buffer) {
  rewind(from_buffer);
  int c;
  while ((c = fgetc(from_buffer)) != EOF)
    fputc(c, to_buffer);
  rewind(from_buffer);
  ftruncate(fileno(from_buffer), 0);
}
__attribute__((format(printf, 1, 2)))
static void printnoln(char *fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  vfprintf(CURR_BUFFER, fmt, ap);
  va_end(ap);
}
__attribute__((format(printf, 1, 2)))
static void println(char *fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  vfprintf(CURR_BUFFER, fmt, ap);
  va_end(ap);
  fputc('\n', CURR_BUFFER);
}
/////////// END PRINTING

static int count(void) {
  static int i = 1;
  return i++;
}

static void emit_line(struct Token *tok) {
  if (opt_line_numbers && tok && tok->line_no && tok->filename)
    println("#line %d \"%s\"", tok->line_no, tok->filename);
}

static int RETURN_TMP;

void print_label(char *label) {
  printnoln("_l");
  for (; *label; label++) {
    if (*label == '.') printnoln("_");
    else               printnoln("%c", *label);
  }
}

static void print_tok(Token *tok) {
  if (tok->str) printnoln("%s", tok->str);
  else {
    assert(tok->loc);
    for (int i = 0; i < tok->len; i++)
      printnoln("%c", tok->loc[i]);
  }
}

void print_obj(Obj *obj) {
  assert(obj->offset >= 0);
  if (obj->is_local || strchr(obj->name, '.')) {
    printnoln("_");
    for (char *c = obj->name; *c; c++)
      if (*c == '.') printnoln("_");
      else           printnoln("%c", *c);
    printnoln("_%d", obj->offset);
  } else {
    printnoln("%s", obj->name);
  }
}

///////// TYPES
const void typedecl(Type *type) {
  if (type->id) return;
  Type *hashed = hash_lookup(type);
  if (hashed && !(hashed->typedecling)) {
    assert(hashed->id);
    type->id = hashed->id;
    if (hashed->pointer_type) type->pointer_type = hashed->pointer_type;
    if (hashed->return_ty)    type->return_ty = hashed->return_ty;
    if (hashed->params)       type->params = hashed->params;
    return;
  }
  type->typedecling = 1;
  type->id = count();
  hash_insert(type);
  switch (type->kind) {
  case TY_FLOAT:
    println("typedef float Type_%d ;", type->id);
    break;
  case TY_DOUBLE:
    println("typedef double Type_%d ;", type->id);
    break;
  case TY_LDOUBLE:
    println("typedef long double Type_%d ;", type->id);
    break;
  case TY_INT:
    if (type->is_unsigned)
      println("typedef unsigned int Type_%d ;", type->id);
    else
      println("typedef int Type_%d ;", type->id);
    break;
  case TY_LONG:
    if (type->is_unsigned)
      println("typedef unsigned long Type_%d ;", type->id);
    else
      println("typedef long Type_%d ;", type->id);
    break;
  case TY_SHORT:
    if (type->is_unsigned)
      println("typedef unsigned short Type_%d ;", type->id);
    else
      println("typedef short Type_%d ;", type->id);
    break;
  case TY_VOID:
    println("typedef void Type_%d ;", type->id);
    break;
  case TY_BOOL:
    println("typedef _Bool Type_%d ;", type->id);
    break;
  case TY_CHAR:
    println("typedef char Type_%d ;", type->id);
    break;
  case TY_PTR:
    // When we recurse, we need to set the type id to 0 because we haven't
    // printed it out yet.
    type->id = 0;
    typedecl(type->base);
    if (!type->id) type->id = count();
    println("typedef Type_%d * Type_%d ;", type->base->id, type->id);
    break;
  case TY_FUNC: {
    type->id = 0;
    typedecl(type->return_ty);
    for (Type *p = type->params; p; p = p->next)
      typedecl(p);
    if (!type->id) type->id = count();
    printnoln("typedef Type_%d Type_%d ( ", type->return_ty->id, type->id); 

    int i = 0;
    for (Type *p = type->params; p; p = p->next, i++)
      if (i) printnoln(", Type_%d ", p->id);
      else   printnoln("Type_%d ", p->id);

    if (type->is_variadic) {
      if (i) printnoln(", ... ");
      // else   printnoln("... ");
    }
    println(") ;");
    break;
  }
  case TY_ARRAY:
    type->id = 0;
    typedecl(type->base);
    if (!type->id) type->id = count();
    if (type->array_len == -1)
      println("typedef Type_%d Type_%d [ ] ;", type->base->id, type->id);
    else
      println("typedef Type_%d Type_%d [ %d ] ;", type->base->id, type->id,
              type->array_len);
    break;
  case TY_STRUCT:
  case TY_UNION:
    if (type->kind == TY_STRUCT)
      println("typedef struct Struct_%d Type_%d ;", type->id, type->id);
    else
      println("typedef union Union_%d Type_%d ;", type->id, type->id);

    for (Member *m = type->members; m; m = m->next)
      typedecl(m->ty);

    if (type->kind == TY_STRUCT) printnoln("struct Struct_%d { ", type->id);
    else                         printnoln("union Union_%d { ", type->id);
    for (Member *m = type->members; m; m = m->next) {
      printnoln("Type_%d ", m->ty->id);
      if (m->name)
        print_tok(m->name);
      else if (m->ty->kind == TY_STRUCT || m->ty->kind == TY_UNION)
        printnoln("___dietc_f%d", m->idx);
      else
        printnoln("__field_%d", count());
      printnoln(" ; ");
    }
    println("} ;");
    break;
  case TY_ENUM:
    println("typedef enum Enum_%d { EN_%d } Type_%d ;", type->id, type->id, type->id);
    break;
  case TY_VLA:
    assert(!"unimplemented vla?");
    break;
  default:
    assert(!"unimplemented?");
    break;
  }
  type->typedecling = 0;
}
void ensure_pointer_to(Type *type) {
  if (type->pointer_type) return;
  type->pointer_type = pointer_to(type);
}
//////////// END TYPES

const void print_type(Type *type) {
  if (type->kind == TY_FUNC) {
    ensure_pointer_to(type);
    print_type(type->pointer_type);
  } else {
    push_buffer(TYPE_BUFFER);
    typedecl(type);
    pop_buffer(TYPE_BUFFER);
    assert(type->id);
    printnoln("Type_%d", type->id);
  }
}
static Obj *current_fn;

static void gen_expr(Node *node, int to_tmp);
static void gen_stmt(Node *node);

// Round up `n` to the nearest multiple of `align`. For instance,
// align_to(5, 8) returns 8 and align_to(11, 8) returns 16.
int align_to(int n, int align) {
  return (n + align - 1) / align * align;
}

void decltmp(Type *type, int c) {
  // Write directly to the main buffer so it decls before the code.
  push_buffer(MAIN_BUFFER);
  printnoln("\t");
  print_type(type);
  println(" t%d ;", c);
  pop_buffer(MAIN_BUFFER);
}

void decltmpptr(Type *type, int c) {
  ensure_pointer_to(type);
  decltmp(type->pointer_type, c);
}

// Compute the absolute address of a given node.
// It's an error if a given node does not reside in memory.
static void gen_addr(Node *node, int to_tmp) {
  switch (node->kind) {
  case ND_VAR:
    decltmpptr(node->ty, to_tmp);
    printnoln("\tt%d = & ", to_tmp);
    print_obj(node->var);
    println(" ;");
    return;
  case ND_DEREF:
    gen_expr(node->lhs, to_tmp);
    return;
  case ND_COMMA:
    gen_expr(node->lhs, count());
    gen_addr(node->rhs, to_tmp);
    return;
  case ND_MEMBER: {
    int s = count();
    gen_addr(node->lhs, s);
    decltmpptr(node->ty, to_tmp);
    printnoln("\tt%d = FIELDPTR ( t%d, ", to_tmp, s);
    if (node->member->name)
      print_tok(node->member->name);
    else
      printnoln("___dietc_f%d", node->member->idx);
    println(" ) ;");
    return;
  }
  case ND_ASSIGN:
  case ND_COND:
    if (node->ty->kind == TY_STRUCT || node->ty->kind == TY_UNION) {
      gen_expr(node, to_tmp);
      return;
    }
    break;
  case ND_VLA_PTR: assert(0);
  }

  error_tok(node->tok, "not an lvalue");
}

// Generate code for a given node.
static void gen_expr(Node *node, int to_tmp) {
  emit_line(node->tok);
  if (opt_type_builtins && (node->is_sizeof || node->is_alignof)) {
    decltmp(node->ty, to_tmp);
    if (node->is_sizeof)  printnoln("\tt%d = sizeof ( ", to_tmp);
    else                  printnoln("\tt%d = _Alignof ( ", to_tmp);
    print_type(node->is_sizeof);
    println(" ) ;");
    return;
  }
  switch (node->kind) {
  case ND_NULL_EXPR:
    return;
  case ND_NUM: {
    decltmp(node->ty, to_tmp);
    switch (node->ty->kind) {
      case TY_FLOAT:
      case TY_DOUBLE:
      case TY_LDOUBLE:
        println("\tt%d = %Lf ;", to_tmp, node->fval);
        return;
      default:
        println("\tt%d = %ld ;", to_tmp, node->val);
        return;
    }
  }
  case ND_NEG: {
    int c = count();
    gen_expr(node->lhs, c);
    decltmp(node->ty, to_tmp);
    println("\tt%d = - t%d ;", to_tmp, c);
    return;
  }
  case ND_VAR: {
    // we inline the *getaddr(node)
    if (node->ty->kind == TY_ARRAY) {
      decltmpptr(node->ty->base, to_tmp);
      printnoln("\tt%d = ", to_tmp);
      print_obj(node->var);
      println(" ;");
    } else {
      decltmp(node->ty, to_tmp);
      printnoln("\tt%d = ", to_tmp);
      print_obj(node->var);
      println(" ;");
    }
    return;
  }
  case ND_MEMBER: {
    int c = count();
    gen_addr(node, c);
    // TODO: what to do in this case?
    if (node->ty->kind == TY_ARRAY) {
      decltmpptr(node->ty->base, to_tmp);
      println("\tt%d = * t%d ;", to_tmp, c);
    } else {
      decltmp(node->ty, to_tmp);
      println("\tt%d = * t%d ;", to_tmp, c);
    }

    if (node->member->is_bitfield)
      fprintf(stderr, "WARNING: bitfields ignored");
    return;
  }
  case ND_DEREF: {
    int c = count();
    gen_expr(node->lhs, c);
    // TODO: deref a pointer to an array; is the temporary a pointer, or an
    // array??
    if (node->ty->kind == TY_ARRAY) {
      decltmpptr(node->ty->base, to_tmp);
      println("\tt%d = * t%d ;", to_tmp, c);
    } else {
      decltmp(node->ty, to_tmp);
      println("\tt%d = * t%d ;", to_tmp, c);
    }
    return;
  }
  case ND_ADDR:
    gen_addr(node->lhs, to_tmp);
    return;
  case ND_ASSIGN: {
    int lhsa = count();
    gen_addr(node->lhs, lhsa);
    gen_expr(node->rhs, to_tmp);

    if (node->lhs->kind == ND_MEMBER && node->lhs->member->is_bitfield)
      fprintf(stderr, "WARNING: bitfields ignored");

    println("\t* t%d = t%d ;", lhsa, to_tmp);
    return;
  }
  case ND_STMT_EXPR:
    for (Node *n = node->body; n; n = n->next) {
      if (n->next || n->kind != ND_EXPR_STMT)
        gen_stmt(n);
      else
        gen_expr(n->lhs, to_tmp);
    }
    return;
  case ND_COMMA:
    gen_expr(node->lhs, count());
    gen_expr(node->rhs, to_tmp);
    return;
  case ND_CAST: {
    if (definitely_same_type(node->lhs->ty, node->ty))
      return gen_expr(node->lhs, to_tmp);
    int c = count();
    if (node->ty->kind == TY_VOID) {
      gen_expr(node->lhs, c);
      push_buffer(TYPE_BUFFER); typedecl(node->ty); pop_buffer(TYPE_BUFFER);
      println("\t( Type_%d ) t%d ;", node->ty->id, c);
    } else if (node->lhs->ty->kind == TY_UNION) {
      // union *tuptr = &union
      int uptr = count();
      gen_addr(node->lhs, uptr);
      // T * tc = ( T * ) tuptr
      decltmpptr(node->ty, c);
      println("\tt%d = ( Type_%d ) t%d ;",
              c, node->ty->pointer_type->id, uptr);
      // dereference it
      decltmp(node->ty, to_tmp);
      println("\tt%d = * t%d ;", to_tmp, c);
    } else {
      gen_expr(node->lhs, c);
      decltmp(node->ty, to_tmp);
      println("\tt%d = ( Type_%d ) t%d ;", to_tmp, node->ty->id, c);
    }
    return;
  }
  case ND_MEMZERO:
    printnoln("\tMEMZERO ( "); print_obj(node->var); println(" ) ;");
    return;
  case ND_COND: {
    int c = count(), cond = count(), condfalse = count(),
        tmp1 = count(), tmp2 = count();
    gen_expr(node->cond, cond);
    decltmp(ty_int, condfalse);
    if (node->ty->kind != TY_VOID)
      decltmp(node->ty, to_tmp);
    println("\tt%d = ! t%d ;", condfalse, cond);
    println("\tif ( t%d ) goto _L_else_%d ;", condfalse, c);
    gen_expr(node->then, tmp1);
    if (node->ty->kind != TY_VOID)
      println("\tt%d = t%d ;", to_tmp, tmp1);
    println("\tgoto _L_end_%d ;", c);
    println("\t_L_else_%d :", c);
    gen_expr(node->els, tmp2);
    if (node->ty->kind != TY_VOID)
      println("\tt%d = t%d ;", to_tmp, tmp2);
    println("\t_L_end_%d :", c);
    return;
  }
  case ND_NOT: {
    int c = count();
    gen_expr(node->lhs, c);
    decltmp(ty_int, to_tmp);
    println("\tt%d = ! t%d ;", to_tmp, c);
    return;
  }
  case ND_BITNOT: {
    int c = count();
    gen_expr(node->lhs, c);
    decltmp(node->ty, to_tmp);
    println("\tt%d = ~ t%d ;", to_tmp, c);
    return;
  }
  case ND_LOGAND: {
    int c = count(), lhs = count(), lhsfalse = count(),
        rhs = count(), rhsfalse = count();
    decltmp(ty_int, to_tmp);
    decltmp(ty_int, lhsfalse);
    decltmp(ty_int, rhsfalse);
    gen_expr(node->lhs, lhs);
    println("\tt%d = 0 ;", to_tmp);
    println("\tt%d = ! t%d ;", lhsfalse, lhs);
    println("\tif ( t%d ) goto _L_false_%d ;", lhsfalse, c);
    gen_expr(node->rhs, rhs);
    println("\tt%d = ! t%d ;", rhsfalse, rhs);
    println("\tif ( t%d ) goto _L_false_%d ;", rhsfalse, c);
    println("\tt%d = 1 ;", to_tmp);
    println("\tgoto _L_end_%d;", c);
    println("\t_L_false_%d :", c);
    println("\t_L_end_%d :", c);
    return;
  }
  case ND_LOGOR: {
    int c = count(), lhs = count(), rhs = count();
    decltmp(ty_int, to_tmp);
    println("\tt%d = 0 ;", to_tmp);
    gen_expr(node->lhs, lhs);
    println("\tif ( t%d ) goto _L_true_%d ;", lhs, c);
    gen_expr(node->rhs, rhs);
    println("\tif ( t%d ) goto _L_true_%d ;", rhs, c);
    println("\tgoto _L_end_%d ;", c);
    println("\t_L_true_%d :", c);
    println("\tt%d = 1 ;", to_tmp);
    println("\t_L_end_%d :", c);
    return;
  }
  case ND_FUNCALL: {
    int fnc = count();
    gen_expr(node->lhs, fnc);

    int n_args = 0;
    for (Node *arg = node->args; arg; arg = arg->next) n_args++;

    int *args = calloc(n_args, sizeof(int)),
        arg_i = 0;
    for (Node *arg = node->args; arg; arg = arg->next, arg_i++) {
      args[arg_i] = count();
      gen_expr(arg, args[arg_i]);
    }
    if (node->ty->kind != TY_VOID) {
      decltmp(node->ty, to_tmp);
      printnoln("\tt%d = ", to_tmp);
    } else {
      printnoln("\t");
    }
    printnoln("t%d ( ", fnc);
    for (int i = 0; i < n_args; i++) {
      if (i) printnoln(", ");
      printnoln("t%d ", args[i]);
    }
    println(") ;");
    return;
  }
  case ND_LABEL_VAL:  assert(0);
  case ND_CAS:        assert(0);
  case ND_EXCH:       assert(0);
  }

  int rhsc = count(), lhsc = count();
  gen_expr(node->rhs, rhsc);
  gen_expr(node->lhs, lhsc);

  char *op = NULL;
  switch (node->kind) {
  case ND_ADD:    op = "+";   break;
  case ND_SUB:    op = "-";   break;
  case ND_MUL:    op = "*";   break;
  case ND_DIV:    op = "/";   break;
  case ND_MOD:    op = "%";   break;
  case ND_BITAND: op = "&";   break;
  case ND_BITOR:  op = "|";   break;
  case ND_BITXOR: op = "^";   break;
  case ND_EQ:     op = "==";  break;
  case ND_NE:     op = "!=";  break;
  case ND_LT:     op = "<";   break;
  case ND_LE:     op = "<=";  break;
  case ND_SHL:    op = "<<";  break;
  case ND_SHR:    op = ">>";  break;
  }

  decltmp(node->ty, to_tmp);
  if (node->ty->base) {
    println("\tt%d = PTR_BINARY ( t%d , %s , t%d ) ;", to_tmp, lhsc, op, rhsc);
  } else {
    println("\tt%d = BINARY ( t%d , %s , t%d ) ;", to_tmp, lhsc, op, rhsc);
  }
}

static void gen_stmt(Node *node) {
  emit_line(node->tok);
  switch (node->kind) {
  case ND_IF: {
    int cond = count(), condfalse = count(), c = count();
    gen_expr(node->cond, cond);
    decltmp(ty_int, condfalse);
    println("\tt%d = ! t%d ;", condfalse, cond);
    println("\tif ( t%d ) goto _L_else_%d ;", condfalse, c);
    gen_stmt(node->then);
    println("\tgoto _L_end_%d ;", c);
    println("\t_L_else_%d :", c);
    if (node->els)
      gen_stmt(node->els);
    println("\t_L_end_%d :", c);
    return;
  }
  case ND_FOR: {
    int c = count(), cond = count(), condfalse = count();
    if (node->init)
      gen_stmt(node->init);
    println("\t_L_begin_%d :", c);
    if (node->cond) {
      gen_expr(node->cond, cond);
      decltmp(ty_int, condfalse);
      println("\tt%d = ! t%d ;", condfalse, cond);
      printnoln("\tif ( t%d ) goto ", condfalse);
      print_label(node->brk_label);
      println(" ;");
    }
    gen_stmt(node->then);
    printnoln("\t"); print_label(node->cont_label); println(" :");
    if (node->inc)
      gen_expr(node->inc, count());
    println("\tgoto _L_begin_%d ;", c);
    printnoln("\t"); print_label(node->brk_label); println(" :");
    return;
  }
  case ND_DO: {
    int c = count(), cond = count();
    println("\t_L_begin_%d :", c);
    gen_stmt(node->then);
    printnoln("\t"); print_label(node->cont_label); println(" :");
    gen_expr(node->cond, cond);
    println("\tif ( t%d ) goto _L_begin_%d ;", cond, c);
    printnoln("\t"); print_label(node->brk_label); println(" :");
    return;
  }
  case ND_SWITCH: {
    int cond = count(), eqtmp = count();
    gen_expr(node->cond, cond);
    decltmp(ty_int, eqtmp);

    for (Node *n = node->case_next; n; n = n->case_next) {
      if (n->begin == n->end) {
        println("\tt%d = BINARY ( t%d , == , %ld ) ;", eqtmp, cond, n->begin);
        printnoln("\tif ( t%d ) goto ", eqtmp);
        print_label(n->label); println(" ;");
        continue;
      }

      // [GNU] Case ranges
      assert(!"unimplemented");
    }

    if (node->default_case) {
      printnoln("\tgoto "); print_label(node->default_case->label); println(" ;");
    }

    printnoln("\tgoto "); print_label(node->brk_label); println(" ;");
    gen_stmt(node->then);
    printnoln("\t"); print_label(node->brk_label); println(" :");
    return;
  }
  case ND_CASE:
    printnoln("\t"); print_label(node->label); println(" :");
    gen_stmt(node->lhs);
    return;
  case ND_BLOCK:
    for (Node *n = node->body; n; n = n->next)
      gen_stmt(n);
    return;
  case ND_GOTO:
    printnoln("\tgoto "); print_label(node->unique_label); println(" ;");
    return;
  case ND_GOTO_EXPR: assert(0); return;
  case ND_LABEL:
    printnoln("\t"); print_label(node->unique_label); println(" :");
    gen_stmt(node->lhs);
    return;
  case ND_RETURN:
    if (node->lhs) {
      int expr = count();
      gen_expr(node->lhs, expr);
      println("\tt%d = t%d ;", RETURN_TMP, expr);
    }
    println("\tgoto _L_RETURN ;");
    return;
  case ND_EXPR_STMT:
    gen_expr(node->lhs, count());
    return;
  case ND_ASM: assert(0); return;
  }

  error_tok(node->tok, "invalid statement");
}

// Assign offsets to local variables.
static void assign_lvar_offsets(Obj *prog) {
  for (Obj *fn = prog; fn; fn = fn->next) {
    if (!fn->is_function)
      continue;

    for (Obj *var = fn->params; var; var = var->next)
      var->offset = count();
    for (Obj *var = fn->locals; var; var = var->next)
      if (!(var->offset))
        var->offset = count();
  }
}

void emit_constant(int pos, char *data, Relocation **rel, Type *type) {
  switch (type->kind) {
  case TY_STRUCT: {
    int i = 0;
    printnoln("{ ");
    for (struct Member *m = type->members; m; m = m->next, i++) {
      if (i) printnoln(", ");
      assert(!m->is_bitfield);
      emit_constant(pos + m->offset, data, rel, m->ty);
    }
    printnoln("} ");
    break;
  }
  case TY_UNION: {
    struct Member *biggest = type->members;
    for (struct Member *m = type->members; m; m = m->next)
      if (m->ty->size > biggest->ty->size) biggest = m;
    assert(biggest);
    printnoln("{ ");
    emit_constant(pos, data, rel, biggest->ty);
    printnoln("} ");
    break;
  }
  case TY_ARRAY: {
    printnoln("{ ");
    for (int i = 0; i < type->array_len; i++) {
      if (i) printnoln(", ");
      emit_constant(pos, data, rel, type->base);
      pos += type->base->size;
    }
    printnoln("} ");
    break;
  }
  case TY_CHAR:
    assert(type->size == 1);
    // we don't output ' ' so lexing can be done by splitting on whitespace
    if (data[pos] > ' ' && data[pos] <= '~' && data[pos] != '\'' && data[pos] != '\\')
      printnoln("'%c' ", data[pos++]);
    else
      printnoln("%d ", (int)data[pos++]);
    break;
  case TY_BOOL:
    assert(type->size == 1);
    printnoln("%d ", *((char*)(data+pos)));
    break;
  case TY_SHORT:
    assert(type->size == sizeof(short));
    printnoln("%d ", *((short*)(data+pos)));
    break;
  case TY_INT:
    assert(type->size == sizeof(int));
    printnoln("%d ", *((int*)(data+pos)));
    break;
  case TY_LONG:
    assert(type->size == sizeof(long));
    printnoln("%ld ", *((long*)(data+pos)));
    break;
  case TY_FLOAT: {
    assert(type->size == sizeof(float));
    float v = *((float*)(data + pos));
    if (v != v) printnoln("0./0. ");
    else if (v == 1./0.) printnoln("1./0. ");
    else if (-v == 1./0.) printnoln("-1./0. ");
    else printnoln("%f ", v);
    break;
  } case TY_DOUBLE: {
    assert(type->size == sizeof(double));
    double v = *((double*)(data + pos));
    if (v != v) printnoln("0./0. ");
    else if (v == 1./0.) printnoln("1./0. ");
    else if (-v == 1./0.) printnoln("-1./0. ");
    else printnoln("%lf ", v);
    break;
  } case TY_LDOUBLE: {
    assert(type->size == sizeof(long double));
    long double v = *((long double*)(data + pos));
    if (v != v) printnoln("0./0. ");
    else if (v == 1./0.) printnoln("1./0. ");
    else if (-v == 1./0.) printnoln("-1./0. ");
    else printnoln("%Lf ", v);
    break;
  } case TY_PTR:
    assert(type->size == 8);
    if (*rel && (*rel)->offset == pos) {
      // TODO: should addend be divided by (*rel)->ty->size?
      printnoln("( void * ) ( & ");
      if (strchr(*((*rel)->label), '.')) {
        printnoln("_");
        for (char *c = *((*rel)->label); *c; c++) {
          if (*c == '.')  printnoln("_");
          else            printnoln("%c", *c);
        }
        printnoln("_0 ) + %ld ", (*rel)->addend);
      } else {
        printnoln("%s ) + %ld ", *((*rel)->label), (*rel)->addend);
      }
      *rel = (*rel)->next;
    } else {
      // TODO: actually read the absolute address out
      printnoln("( void * ) ( %ld ) + 0 ", *((uint64_t*)(data+pos)));
    }
    break;
  case TY_ENUM:
    switch (type->size) {
    case sizeof(int):
      printnoln("%d ", *((int*)(data+pos)));
      break;
    case sizeof(long):
      printnoln("%ld ", *((long*)(data+pos)));
      break;
    default: assert(0);
    }
    break;
  default: fprintf(stderr, "Got: %d\n", type->kind); assert(0);
  }
}

static void emit_data(Obj *prog) {
  for (Obj *var = prog; var; var = var->next) {
    push_buffer(TYPE_BUFFER);
    typedecl(var->ty);
    pop_buffer(TYPE_BUFFER);
    if (var->is_static && var->is_function) {
      printnoln("static Type_%d ", var->ty->id);
      print_obj(var); println(" ;");
    } else if (var->is_static) {
      printnoln("static Type_%d ", var->ty->id);
      print_obj(var); println(" ;");
    } else {
      printnoln("extern Type_%d ", var->ty->id);
      print_obj(var); println(" ;");
    }
  }

  for (Obj *var = prog; var; var = var->next) {
    if (var->is_function || !var->is_definition)
      continue;

    if (var->is_static) printnoln("static ");
    print_type(var->ty); printnoln(" "); print_obj(var);

    // Common symbol
    assert(!(opt_fcommon && var->is_tentative));

    // .data or .tdata
    if (var->init_data) {
      printnoln(" = ");
      Relocation *rel = var->rel;
      emit_constant(0, var->init_data, &rel, var->ty);
    }
    println(";");
  }
}

static void emit_text(Obj *prog) {
  for (Obj *fn = prog; fn; fn = fn->next) {
    if (!fn->is_function || !fn->is_definition)
      continue;

    emit_line(fn->body->tok);

    // No code is emitted for "static inline" functions
    // if no one is referencing them.
    if (!fn->is_live)
      continue;

    current_fn = fn;

    if (fn->is_static)
      printnoln("static ");

    print_type(fn->ty->return_ty); printnoln(" ");
    printnoln("%s ( ", fn->name);
    int p = 0;
    for (Obj *param = fn->params; param; param = param->next, p++) {
      if (p) printnoln(", ");
      print_type(param->ty); printnoln(" "); print_obj(param);
      param->is_param = 1;
      printnoln(" ");
    }
    if (fn->va_area) {
      if (p) printnoln(", ... ");
      // else   printnoln("... ");
    }
    println(") {");

    RETURN_TMP = 0;
    if (fn->ty->return_ty->kind != TY_VOID) {
      RETURN_TMP = count();
      decltmp(fn->ty->return_ty, RETURN_TMP);
    }

    for (Obj *var = fn->locals; var; var = var->next) {
      if (var->is_param) continue;
      if (var == fn->va_area) continue;
      if (var == fn->alloca_bottom) continue;
      printnoln("\t");
      print_type(var->ty);
      printnoln(" ");
      print_obj(var);
      println(" ;");
    }

    // Emit code
    push_buffer(CODE_BUFFER);
    gen_stmt(fn->body);
    pop_buffer(CODE_BUFFER);
    flush_buffer(MAIN_BUFFER, CODE_BUFFER);

    println("\t_L_RETURN :");
    if (fn->ty->return_ty->kind != TY_VOID) {
      println("\treturn t%d ;", RETURN_TMP);
    } else {
      println("\treturn ;");
    }

    println("}");
  }
}

void codegen(Obj *prog, FILE *out) {
  TYPE_BUFFER = tmpfile();
  MAIN_BUFFER = tmpfile();
  CODE_BUFFER = tmpfile();
  assign_lvar_offsets(prog);

  // Everything defaults to writing to main
  push_buffer(MAIN_BUFFER);
  emit_data(prog);
  emit_text(prog);
  pop_buffer(MAIN_BUFFER);

  fprintf(out, "#include \"%s/scripts/dietc_helpers.h\"\n", DIETC_ROOT);
  flush_buffer(out, TYPE_BUFFER);
  flush_buffer(out, MAIN_BUFFER);
}