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/*
** LuaJIT VM builder: Assembler source code emitter.
** Copyright (C) 2005-2009 Mike Pall. See Copyright Notice in luajit.h
*/
#include "buildvm.h"
#include "lj_bc.h"
/* ------------------------------------------------------------------------ */
/* Emit bytes piecewise as assembler text. */
static void emit_asm_bytes(BuildCtx *ctx, uint8_t *p, int n)
{
int i;
for (i = 0; i < n; i++) {
if ((i & 15) == 0)
fprintf(ctx->fp, "\t.byte %d", p[i]);
else
fprintf(ctx->fp, ",%d", p[i]);
if ((i & 15) == 15) putc('\n', ctx->fp);
}
if ((n & 15) != 0) putc('\n', ctx->fp);
}
/* Emit relocation */
static void emit_asm_reloc(BuildCtx *ctx, BuildReloc *r)
{
const char *sym = ctx->extnames[r->sym];
switch (ctx->mode) {
case BUILD_elfasm:
if (r->type)
fprintf(ctx->fp, "\t.long %s-.-4\n", sym);
else
fprintf(ctx->fp, "\t.long %s\n", sym);
break;
case BUILD_coffasm:
fprintf(ctx->fp, "\t.def _%s; .scl 3; .type 32; .endef\n", sym);
if (r->type)
fprintf(ctx->fp, "\t.long _%s-.-4\n", sym);
else
fprintf(ctx->fp, "\t.long _%s\n", sym);
break;
default: /* BUILD_machasm for relative relocations handled below. */
fprintf(ctx->fp, "\t.long _%s\n", sym);
break;
}
}
static const char *const jccnames[] = {
"jo", "jno", "jb", "jnb", "jz", "jnz", "jbe", "ja",
"js", "jns", "jpe", "jpo", "jl", "jge", "jle", "jg"
};
/* Emit relocation for the incredibly stupid OSX assembler. */
static void emit_asm_reloc_mach(BuildCtx *ctx, uint8_t *cp, int n,
const char *sym)
{
const char *opname = NULL;
if (--n < 0) goto err;
if (cp[n] == 0xe8) {
opname = "call";
} else if (cp[n] == 0xe9) {
opname = "jmp";
} else if (cp[n] >= 0x80 && cp[n] <= 0x8f && n > 0 && cp[n-1] == 0x0f) {
opname = jccnames[cp[n]-0x80];
n--;
} else {
err:
fprintf(stderr, "Error: unsupported opcode for %s symbol relocation.\n",
sym);
exit(1);
}
emit_asm_bytes(ctx, cp, n);
if (!strncmp(sym, LABEL_PREFIX, sizeof(LABEL_PREFIX)-1))
fprintf(ctx->fp, "\t%s _%s\n", opname, sym);
else
fprintf(ctx->fp, "\t%s _" LABEL_PREFIX "wrapper_%s\n", opname, sym);
}
/* Emit an assembler label. */
static void emit_asm_label(BuildCtx *ctx, const char *name, int size, int isfunc)
{
switch (ctx->mode) {
case BUILD_elfasm:
fprintf(ctx->fp,
"\n\t.globl %s\n"
"\t.hidden %s\n"
"\t.type %s, @%s\n"
"\t.size %s, %d\n"
"%s:\n",
name, name, name, isfunc ? "function" : "object", name, size, name);
break;
case BUILD_coffasm:
fprintf(ctx->fp, "\n\t.globl _%s\n", name);
if (isfunc)
fprintf(ctx->fp, "\t.def _%s; .scl 3; .type 32; .endef\n", name);
fprintf(ctx->fp, "_%s:\n", name);
break;
case BUILD_machasm:
fprintf(ctx->fp,
"\n\t.private_extern _%s\n"
"_%s:\n", name, name);
break;
default:
break;
}
}
/* Emit alignment. */
static void emit_asm_align(BuildCtx *ctx, int bits)
{
switch (ctx->mode) {
case BUILD_elfasm:
case BUILD_coffasm:
fprintf(ctx->fp, "\t.p2align %d\n", bits);
break;
case BUILD_machasm:
fprintf(ctx->fp, "\t.align %d\n", bits);
break;
default:
break;
}
}
/* ------------------------------------------------------------------------ */
/* Emit assembler source code. */
void emit_asm(BuildCtx *ctx)
{
char name[80];
int32_t prev;
int i, pi, rel;
fprintf(ctx->fp, "\t.file \"buildvm_%s.dasc\"\n", ctx->dasm_arch);
fprintf(ctx->fp, "\t.text\n");
emit_asm_align(ctx, 4);
emit_asm_label(ctx, LABEL_ASM_BEGIN, 0, 1);
if (ctx->mode == BUILD_elfasm)
fprintf(ctx->fp, ".Lbegin:\n");
i = 0;
do {
pi = ctx->perm[i++];
prev = ctx->sym_ofs[pi];
} while (prev < 0); /* Skip the _Z symbols. */
for (rel = 0; i <= ctx->nsym; i++) {
int ni = ctx->perm[i];
int32_t next = ctx->sym_ofs[ni];
int size = (int)(next - prev);
int32_t stop = next;
if (pi >= ctx->npc) {
sprintf(name, LABEL_PREFIX "%s", ctx->globnames[pi-ctx->npc]);
emit_asm_label(ctx, name, size, 1);
#if LJ_HASJIT
} else {
#else
} else if (!(pi == BC_JFORI || pi == BC_JFORL || pi == BC_JITERL ||
pi == BC_JLOOP || pi == BC_IFORL || pi == BC_IITERL ||
pi == BC_ILOOP)) {
#endif
sprintf(name, LABEL_PREFIX_BC "%s", bc_names[pi]);
emit_asm_label(ctx, name, size, 1);
}
while (rel < ctx->nreloc && ctx->reloc[rel].ofs < stop) {
int n = ctx->reloc[rel].ofs - prev;
if (ctx->mode == BUILD_machasm && ctx->reloc[rel].type != 0) {
emit_asm_reloc_mach(ctx, ctx->code+prev, n,
ctx->extnames[ctx->reloc[rel].sym]);
} else {
emit_asm_bytes(ctx, ctx->code+prev, n);
emit_asm_reloc(ctx, &ctx->reloc[rel]);
}
prev += n+4;
rel++;
}
emit_asm_bytes(ctx, ctx->code+prev, stop-prev);
prev = next;
pi = ni;
}
switch (ctx->mode) {
case BUILD_elfasm:
fprintf(ctx->fp, "\n\t.section .rodata\n");
break;
case BUILD_coffasm:
fprintf(ctx->fp, "\n\t.section .rdata,\"dr\"\n");
break;
case BUILD_machasm:
fprintf(ctx->fp, "\n\t.const\n");
break;
default:
break;
}
emit_asm_align(ctx, 5);
emit_asm_label(ctx, LABEL_OP_OFS, 2*ctx->npc, 0);
for (i = 0; i < ctx->npc; i++)
fprintf(ctx->fp, "\t.short %d\n", ctx->sym_ofs[i]);
fprintf(ctx->fp, "\n");
switch (ctx->mode) {
case BUILD_elfasm:
fprintf(ctx->fp, "\t.section .note.GNU-stack,\"\",@progbits\n");
/* fallthrough */
case BUILD_coffasm:
fprintf(ctx->fp, "\t.ident \"%s\"\n", ctx->dasm_ident);
break;
case BUILD_machasm:
fprintf(ctx->fp,
"\t.cstring\n"
"\t.ascii \"%s\\0\"\n", ctx->dasm_ident);
break;
default:
break;
}
fprintf(ctx->fp, "\n");
}
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