source/libs/luajit/LuaJIT-src/src/host/buildvm_asm.c

   1 /*
   2 ** LuaJIT VM builder: Assembler source code emitter.
   3 ** Copyright (C) 2005-2015 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #include "buildvm.h"
   7 #include "lj_bc.h"
   8
   9 /* ------------------------------------------------------------------------ */
  10
  11 #if LJ_TARGET_X86ORX64
  12 /* Emit bytes piecewise as assembler text. */
  13 static void emit_asm_bytes(BuildCtx *ctx, uint8_t *p, int n)
  14 {
  15   int i;
  16   for (i = 0; i < n; i++) {
  17     if ((i & 15) == 0)
  18       fprintf(ctx->fp, "\t.byte %d", p[i]);
  19     else
  20       fprintf(ctx->fp, ",%d", p[i]);
  21     if ((i & 15) == 15) putc('\n', ctx->fp);
  22   }
  23   if ((n & 15) != 0) putc('\n', ctx->fp);
  24 }
  25
  26 /* Emit relocation */
  27 static void emit_asm_reloc(BuildCtx *ctx, int type, const char *sym)
  28 {
  29   switch (ctx->mode) {
  30   case BUILD_elfasm:
  31     if (type)
  32       fprintf(ctx->fp, "\t.long %s-.-4\n", sym);
  33     else
  34       fprintf(ctx->fp, "\t.long %s\n", sym);
  35     break;
  36   case BUILD_coffasm:
  37     fprintf(ctx->fp, "\t.def %s; .scl 3; .type 32; .endef\n", sym);
  38     if (type)
  39       fprintf(ctx->fp, "\t.long %s-.-4\n", sym);
  40     else
  41       fprintf(ctx->fp, "\t.long %s\n", sym);
  42     break;
  43   default:  /* BUILD_machasm for relative relocations handled below. */
  44     fprintf(ctx->fp, "\t.long %s\n", sym);
  45     break;
  46   }
  47 }
  48
  49 static const char *const jccnames[] = {
  50   "jo", "jno", "jb", "jnb", "jz", "jnz", "jbe", "ja",
  51   "js", "jns", "jpe", "jpo", "jl", "jge", "jle", "jg"
  52 };
  53
  54 /* Emit x86/x64 text relocations. */
  55 static void emit_asm_reloc_text(BuildCtx *ctx, uint8_t *cp, int n,
  56                                 const char *sym)
  57 {
  58   const char *opname = NULL;
  59   if (--n < 0) goto err;
  60   if (cp[n] == 0xe8) {
  61     opname = "call";
  62   } else if (cp[n] == 0xe9) {
  63     opname = "jmp";
  64   } else if (cp[n] >= 0x80 && cp[n] <= 0x8f && n > 0 && cp[n-1] == 0x0f) {
  65     opname = jccnames[cp[n]-0x80];
  66     n--;
  67   } else {
  68 err:
  69     fprintf(stderr, "Error: unsupported opcode for %s symbol relocation.\n",
  70             sym);
  71     exit(1);
  72   }
  73   emit_asm_bytes(ctx, cp, n);
  74   if (strncmp(sym+(*sym == '_'), LABEL_PREFIX, sizeof(LABEL_PREFIX)-1)) {
  75     /* Various fixups for external symbols outside of our binary. */
  76     if (ctx->mode == BUILD_elfasm) {
  77       if (LJ_32)
  78         fprintf(ctx->fp, "#if __PIC__\n\t%s lj_wrap_%s\n#else\n", opname, sym);
  79       fprintf(ctx->fp, "\t%s %s@PLT\n", opname, sym);
  80       if (LJ_32)
  81         fprintf(ctx->fp, "#endif\n");
  82       return;
  83     } else if (LJ_32 && ctx->mode == BUILD_machasm) {
  84       fprintf(ctx->fp, "\t%s L%s$stub\n", opname, sym);
  85       return;
  86     }
  87   }
  88   fprintf(ctx->fp, "\t%s %s\n", opname, sym);
  89 }
  90 #else
  91 /* Emit words piecewise as assembler text. */
  92 static void emit_asm_words(BuildCtx *ctx, uint8_t *p, int n)
  93 {
  94   int i;
  95   for (i = 0; i < n; i += 4) {
  96     if ((i & 15) == 0)
  97       fprintf(ctx->fp, "\t.long 0x%08x", *(uint32_t *)(p+i));
  98     else
  99       fprintf(ctx->fp, ",0x%08x", *(uint32_t *)(p+i));
 100     if ((i & 15) == 12) putc('\n', ctx->fp);
 101   }
 102   if ((n & 15) != 0) putc('\n', ctx->fp);
 103 }
 104
 105 /* Emit relocation as part of an instruction. */
 106 static void emit_asm_wordreloc(BuildCtx *ctx, uint8_t *p, int n,
 107                                const char *sym)
 108 {
 109   uint32_t ins;
 110   emit_asm_words(ctx, p, n-4);
 111   ins = *(uint32_t *)(p+n-4);
 112 #if LJ_TARGET_ARM
 113   if ((ins & 0xff000000u) == 0xfa000000u) {
 114     fprintf(ctx->fp, "\tblx %s\n", sym);
 115   } else if ((ins & 0x0e000000u) == 0x0a000000u) {
 116     fprintf(ctx->fp, "\t%s%.2s %s\n", (ins & 0x01000000u) ? "bl" : "b",
 117             &"eqnecsccmiplvsvchilsgeltgtle"[2*(ins >> 28)], sym);
 118   } else {
 119     fprintf(stderr,
 120             "Error: unsupported opcode %08x for %s symbol relocation.\n",
 121             ins, sym);
 122     exit(1);
 123   }
 124 #elif LJ_TARGET_ARM64
 125   if ((ins >> 26) == 0x25u) {
 126     fprintf(ctx->fp, "\tbl %s\n", sym);
 127   } else {
 128     fprintf(stderr,
 129             "Error: unsupported opcode %08x for %s symbol relocation.\n",
 130             ins, sym);
 131     exit(1);
 132   }
 133 #elif LJ_TARGET_PPC
 134 #if LJ_TARGET_PS3
 135 #define TOCPREFIX "."
 136 #else
 137 #define TOCPREFIX ""
 138 #endif
 139   if ((ins >> 26) == 16) {
 140     fprintf(ctx->fp, "\t%s %d, %d, " TOCPREFIX "%s\n",
 141             (ins & 1) ? "bcl" : "bc", (ins >> 21) & 31, (ins >> 16) & 31, sym);
 142   } else if ((ins >> 26) == 18) {
 143 #if LJ_ARCH_PPC64
 144     const char *suffix = strchr(sym, '@');
 145     if (suffix && suffix[1] == 'h') {
 146       fprintf(ctx->fp, "\taddis 11, 2, %s\n", sym);
 147     } else if (suffix && suffix[1] == 'l') {
 148       fprintf(ctx->fp, "\tld 12, %s\n", sym);
 149     } else
 150 #endif
 151     fprintf(ctx->fp, "\t%s " TOCPREFIX "%s\n", (ins & 1) ? "bl" : "b", sym);
 152   } else {
 153     fprintf(stderr,
 154             "Error: unsupported opcode %08x for %s symbol relocation.\n",
 155             ins, sym);
 156     exit(1);
 157   }
 158 #elif LJ_TARGET_MIPS
 159   fprintf(stderr,
 160           "Error: unsupported opcode %08x for %s symbol relocation.\n",
 161           ins, sym);
 162   exit(1);
 163 #else
 164 #error "missing relocation support for this architecture"
 165 #endif
 166 }
 167 #endif
 168
 169 #if LJ_TARGET_ARM
 170 #define ELFASM_PX       "%%"
 171 #else
 172 #define ELFASM_PX       "@"
 173 #endif
 174
 175 /* Emit an assembler label. */
 176 static void emit_asm_label(BuildCtx *ctx, const char *name, int size, int isfunc)
 177 {
 178   switch (ctx->mode) {
 179   case BUILD_elfasm:
 180 #if LJ_TARGET_PS3
 181     if (!strncmp(name, "lj_vm_", 6) &&
 182         strcmp(name, ctx->beginsym) &&
 183         !strstr(name, "hook")) {
 184       fprintf(ctx->fp,
 185         "\n\t.globl %s\n"
 186         "\t.section \".opd\",\"aw\"\n"
 187         "%s:\n"
 188         "\t.long .%s,.TOC.@tocbase32\n"
 189         "\t.size %s,8\n"
 190         "\t.previous\n"
 191         "\t.globl .%s\n"
 192         "\t.hidden .%s\n"
 193         "\t.type .%s, " ELFASM_PX "function\n"
 194         "\t.size .%s, %d\n"
 195         ".%s:\n",
 196         name, name, name, name, name, name, name, name, size, name);
 197       break;
 198     }
 199 #endif
 200     fprintf(ctx->fp,
 201       "\n\t.globl %s\n"
 202       "\t.hidden %s\n"
 203       "\t.type %s, " ELFASM_PX "%s\n"
 204       "\t.size %s, %d\n"
 205       "%s:\n",
 206       name, name, name, isfunc ? "function" : "object", name, size, name);
 207     break;
 208   case BUILD_coffasm:
 209     fprintf(ctx->fp, "\n\t.globl %s\n", name);
 210     if (isfunc)
 211       fprintf(ctx->fp, "\t.def %s; .scl 3; .type 32; .endef\n", name);
 212     fprintf(ctx->fp, "%s:\n", name);
 213     break;
 214   case BUILD_machasm:
 215     fprintf(ctx->fp,
 216       "\n\t.private_extern %s\n"
 217       "%s:\n", name, name);
 218     break;
 219   default:
 220     break;
 221   }
 222 }
 223
 224 /* Emit alignment. */
 225 static void emit_asm_align(BuildCtx *ctx, int bits)
 226 {
 227   switch (ctx->mode) {
 228   case BUILD_elfasm:
 229   case BUILD_coffasm:
 230     fprintf(ctx->fp, "\t.p2align %d\n", bits);
 231     break;
 232   case BUILD_machasm:
 233     fprintf(ctx->fp, "\t.align %d\n", bits);
 234     break;
 235   default:
 236     break;
 237   }
 238 }
 239
 240 /* ------------------------------------------------------------------------ */
 241
 242 /* Emit assembler source code. */
 243 void emit_asm(BuildCtx *ctx)
 244 {
 245   int i, rel;
 246
 247   fprintf(ctx->fp, "\t.file \"buildvm_%s.dasc\"\n", ctx->dasm_arch);
 248 #if LJ_ARCH_PPC64
 249   fprintf(ctx->fp, "\t.abiversion 2\n");
 250 #endif
 251   fprintf(ctx->fp, "\t.text\n");
 252   emit_asm_align(ctx, 4);
 253
 254 #if LJ_TARGET_PS3
 255   emit_asm_label(ctx, ctx->beginsym, ctx->codesz, 0);
 256 #else
 257   emit_asm_label(ctx, ctx->beginsym, 0, 0);
 258 #endif
 259   if (ctx->mode != BUILD_machasm)
 260     fprintf(ctx->fp, ".Lbegin:\n");
 261
 262 #if LJ_TARGET_ARM && defined(__GNUC__) && !LJ_NO_UNWIND
 263   /* This should really be moved into buildvm_arm.dasc. */
 264   fprintf(ctx->fp,
 265           ".fnstart\n"
 266           ".save {r4, r5, r6, r7, r8, r9, r10, r11, lr}\n"
 267           ".pad #28\n");
 268 #endif
 269 #if LJ_TARGET_MIPS
 270   fprintf(ctx->fp, ".set nomips16\n.abicalls\n.set noreorder\n.set nomacro\n");
 271 #endif
 272
 273   for (i = rel = 0; i < ctx->nsym; i++) {
 274     int32_t ofs = ctx->sym[i].ofs;
 275     int32_t next = ctx->sym[i+1].ofs;
 276 #if LJ_TARGET_ARM && defined(__GNUC__) && !LJ_NO_UNWIND && LJ_HASFFI
 277     if (!strcmp(ctx->sym[i].name, "lj_vm_ffi_call"))
 278       fprintf(ctx->fp,
 279               ".globl lj_err_unwind_arm\n"
 280               ".personality lj_err_unwind_arm\n"
 281               ".fnend\n"
 282               ".fnstart\n"
 283               ".save {r4, r5, r11, lr}\n"
 284               ".setfp r11, sp\n");
 285 #endif
 286     emit_asm_label(ctx, ctx->sym[i].name, next - ofs, 1);
 287     while (rel < ctx->nreloc && ctx->reloc[rel].ofs <= next) {
 288       BuildReloc *r = &ctx->reloc[rel];
 289       int n = r->ofs - ofs;
 290 #if LJ_TARGET_X86ORX64
 291       if (r->type != 0 &&
 292           (ctx->mode == BUILD_elfasm || ctx->mode == BUILD_machasm)) {
 293         emit_asm_reloc_text(ctx, ctx->code+ofs, n, ctx->relocsym[r->sym]);
 294       } else {
 295         emit_asm_bytes(ctx, ctx->code+ofs, n);
 296         emit_asm_reloc(ctx, r->type, ctx->relocsym[r->sym]);
 297       }
 298       ofs += n+4;
 299 #else
 300       emit_asm_wordreloc(ctx, ctx->code+ofs, n, ctx->relocsym[r->sym]);
 301       ofs += n;
 302 #endif
 303       rel++;
 304     }
 305 #if LJ_TARGET_X86ORX64
 306     emit_asm_bytes(ctx, ctx->code+ofs, next-ofs);
 307 #else
 308     emit_asm_words(ctx, ctx->code+ofs, next-ofs);
 309 #endif
 310   }
 311
 312 #if LJ_TARGET_ARM && defined(__GNUC__) && !LJ_NO_UNWIND
 313   fprintf(ctx->fp,
 314 #if !LJ_HASFFI
 315           ".globl lj_err_unwind_arm\n"
 316           ".personality lj_err_unwind_arm\n"
 317 #endif
 318           ".fnend\n");
 319 #endif
 320
 321   fprintf(ctx->fp, "\n");
 322   switch (ctx->mode) {
 323   case BUILD_elfasm:
 324 #if !(LJ_TARGET_PS3 || LJ_TARGET_PSVITA)
 325     fprintf(ctx->fp, "\t.section .note.GNU-stack,\"\"," ELFASM_PX "progbits\n");
 326 #endif
 327 #if LJ_TARGET_PPC && !LJ_TARGET_PS3
 328     /* Hard-float ABI. */
 329     fprintf(ctx->fp, "\t.gnu_attribute 4, 1\n");
 330 #endif
 331     /* fallthrough */
 332   case BUILD_coffasm:
 333     fprintf(ctx->fp, "\t.ident \"%s\"\n", ctx->dasm_ident);
 334     break;
 335   case BUILD_machasm:
 336     fprintf(ctx->fp,
 337       "\t.cstring\n"
 338       "\t.ascii \"%s\\0\"\n", ctx->dasm_ident);
 339     break;
 340   default:
 341     break;
 342   }
 343   fprintf(ctx->fp, "\n");
 344 }
 345