emit.c

   1 #include "all.h"
   2
   3 void
   4 emitlnk(char *n, Lnk *l, char *s, FILE *f)
   5 {
   6         char *p;
   7
   8         if (l->sec) {
   9                 fprintf(f, ".section %s", l->sec);
  10                 if (l->secf)
  11                         fprintf(f, ", %s", l->secf);
  12         } else {
  13                 fputs(s, f);
  14         }
  15         fputc('\n', f);
  16         if (l->align)
  17                 fprintf(f, ".balign %d\n", l->align);
  18         p = n[0] == '"' ? "" : T.assym;
  19         if (l->export)
  20                 fprintf(f, ".globl %s%s\n", p, n);
  21         fprintf(f, "%s%s:\n", p, n);
  22 }
  23
  24 void
  25 emitdat(Dat *d, FILE *f)
  26 {
  27         static char *dtoa[] = {
  28                 [DB] = "\t.byte",
  29                 [DH] = "\t.short",
  30                 [DW] = "\t.int",
  31                 [DL] = "\t.quad"
  32         };
  33         static int64_t zero;
  34         char *p;
  35
  36         switch (d->type) {
  37         case DStart:
  38                 zero = 0;
  39                 break;
  40         case DEnd:
  41                 if (zero != -1) {
  42                         emitlnk(d->name, d->lnk, ".bss", f);
  43                         fprintf(f, "\t.fill %"PRId64",1,0\n", zero);
  44                 }
  45                 break;
  46         case DZ:
  47                 if (zero != -1)
  48                         zero += d->u.num;
  49                 else
  50                         fprintf(f, "\t.fill %"PRId64",1,0\n", d->u.num);
  51                 break;
  52         default:
  53                 if (zero != -1) {
  54                         emitlnk(d->name, d->lnk, ".data", f);
  55                         if (zero > 0)
  56                                 fprintf(f, "\t.fill %"PRId64",1,0\n", zero);
  57                         zero = -1;
  58                 }
  59                 if (d->isstr) {
  60                         if (d->type != DB)
  61                                 err("strings only supported for 'b' currently");
  62                         fprintf(f, "\t.ascii %s\n", d->u.str);
  63                 }
  64                 else if (d->isref) {
  65                         p = d->u.ref.name[0] == '"' ? "" : T.assym;
  66                         fprintf(f, "%s %s%s%+"PRId64"\n",
  67                                 dtoa[d->type], p, d->u.ref.name,
  68                                 d->u.ref.off);
  69                 }
  70                 else {
  71                         fprintf(f, "%s %"PRId64"\n",
  72                                 dtoa[d->type], d->u.num);
  73                 }
  74                 break;
  75         }
  76 }
  77
  78 typedef struct Asmbits Asmbits;
  79
  80 struct Asmbits {
  81         char bits[16];
  82         int size;
  83         Asmbits *link;
  84 };
  85
  86 static Asmbits *stash;
  87
  88 int
  89 stashbits(void *bits, int size)
  90 {
  91         Asmbits **pb, *b;
  92         int i;
  93
  94         assert(size == 4 || size == 8 || size == 16);
  95         for (pb=&stash, i=0; (b=*pb); pb=&b->link, i++)
  96                 if (size <= b->size)
  97                 if (memcmp(bits, b->bits, size) == 0)
  98                         return i;
  99         b = emalloc(sizeof *b);
 100         memcpy(b->bits, bits, size);
 101         b->size = size;
 102         b->link = 0;
 103         *pb = b;
 104         return i;
 105 }
 106
 107 static void
 108 emitfin(FILE *f, char *sec[3])
 109 {
 110         Asmbits *b;
 111         char *p;
 112         int lg, i;
 113         double d;
 114
 115         if (!stash)
 116                 return;
 117         fprintf(f, "/* floating point constants */\n");
 118         for (lg=4; lg>=2; lg--)
 119                 for (b=stash, i=0; b; b=b->link, i++) {
 120                         if (b->size == (1<<lg)) {
 121                                 fprintf(f,
 122                                         ".section %s\n"
 123                                         ".p2align %d\n"
 124                                         "%sfp%d:",
 125                                         sec[lg-2], lg, T.asloc, i
 126                                 );
 127                                 for (p=b->bits; p<&b->bits[b->size]; p+=4)
 128                                         fprintf(f, "\n\t.int %"PRId32,
 129                                                 *(int32_t *)p);
 130                                 if (lg <= 3) {
 131                                         if (lg == 2)
 132                                                 d = *(float *)b->bits;
 133                                         else
 134                                                 d = *(double *)b->bits;
 135                                         fprintf(f, " /* %f */\n\n", d);
 136                                 } else
 137                                         fprintf(f, "\n\n");
 138                         }
 139                 }
 140         while ((b=stash)) {
 141                 stash = b->link;
 142                 free(b);
 143         }
 144 }
 145
 146 void
 147 elf_emitfin(FILE *f)
 148 {
 149         static char *sec[3] = { ".rodata", ".rodata", ".rodata" };
 150
 151         emitfin(f ,sec);
 152         fprintf(f, ".section .note.GNU-stack,\"\",@progbits\n");
 153 }
 154
 155 void
 156 elf_emitfnfin(char *fn, FILE *f)
 157 {
 158         fprintf(f, ".type %s, @function\n", fn);
 159         fprintf(f, ".size %s, .-%s\n", fn, fn);
 160 }
 161
 162 void
 163 macho_emitfin(FILE *f)
 164 {
 165         static char *sec[3] = {
 166                 "__TEXT,__literal4,4byte_literals",
 167                 "__TEXT,__literal8,8byte_literals",
 168                 ".rodata", /* should not happen */
 169         };
 170
 171         emitfin(f, sec);
 172 }