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Check relative jump distances for x64.

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This commit is contained in:
Mike Pall 2010-02-24 01:29:11 +01:00
parent 47da0d8018
commit 2f3a917f2f
1 changed files with 18 additions and 9 deletions
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27
src/lj_asm.c
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@ -183,7 +183,7 @@ static void emit_rr(ASMState *as, x86Op xo, Reg r1, Reg r2)
#if LJ_64 && defined(LUA_USE_ASSERT)
/* [addr] is sign-extended in x64 and must be in lower 2G (not 4G). */
static int32_t ptr2addr(void *p)
static int32_t ptr2addr(const void *p)
{
lua_assert((uintptr_t)p < (uintptr_t)0x80000000);
return i32ptr(p);
@ -414,7 +414,9 @@ typedef MCode *MCLabel;
static void emit_sjcc(ASMState *as, int cc, MCLabel target)
{
MCode *p = as->mcp;
p[-1] = (MCode)(int8_t)(target-p);
ptrdiff_t delta = target - p;
lua_assert(delta == (int8_t)delta);
p[-1] = (MCode)(int8_t)delta;
p[-2] = (MCode)(XI_JCCs+(cc&15));
as->mcp = p - 2;
}
@ -438,12 +440,19 @@ static void emit_sfixup(ASMState *as, MCLabel source)
/* Return label pointing to current PC. */
#define emit_label(as) ((as)->mcp)
/* Compute relative 32 bit offset for jump and call instructions. */
static LJ_AINLINE int32_t jmprel(MCode *p, MCode *target)
{
ptrdiff_t delta = target - p;
lua_assert(delta == (int32_t)delta);
return (int32_t)delta;
}
/* jcc target */
static void emit_jcc(ASMState *as, int cc, MCode *target)
{
MCode *p = as->mcp;
int32_t addr = (int32_t)(target - p);
*(int32_t *)(p-4) = addr;
*(int32_t *)(p-4) = jmprel(p, target);
p[-5] = (MCode)(XI_JCCn+(cc&15));
p[-6] = 0x0f;
as->mcp = p - 6;
@ -453,7 +462,7 @@ static void emit_jcc(ASMState *as, int cc, MCode *target)
static void emit_call_(ASMState *as, MCode *target)
{
MCode *p = as->mcp;
*(int32_t *)(p-4) = (int32_t)(target - p);
*(int32_t *)(p-4) = jmprel(p, target);
p[-5] = XI_CALL;
as->mcp = p - 5;
}
@ -925,7 +934,7 @@ static MCode *asm_exitstub_gen(ASMState *as, ExitNo group)
*(int32_t *)mxp = ptr2addr(J2GG(as->J)->dispatch); mxp += 4;
/* Jump to exit handler which fills in the ExitState. */
*mxp++ = XI_JMP; mxp += 4;
*((int32_t *)(mxp-4)) = (int32_t)((MCode *)lj_vm_exit_handler - mxp);
*((int32_t *)(mxp-4)) = jmprel(mxp, (MCode *)(void *)lj_vm_exit_handler);
/* Commit the code for this group (even if assembly fails later on). */
lj_mcode_commitbot(as->J, mxp);
as->mcbot = mxp;
@ -3165,7 +3174,7 @@ static void asm_tail_fixup(ASMState *as, TraceNo lnk)
/* Patch exit branch. */
target = lnk == TRACE_INTERP ? (MCode *)lj_vm_exit_interp :
as->J->trace[lnk]->mcode;
*(int32_t *)(p-4) = (int32_t)(target - p);
*(int32_t *)(p-4) = jmprel(p, target);
p[-5] = XI_JMP;
/* Drop unused mcode tail. Fill with NOPs to make the prefetcher happy. */
for (q = as->mctop-1; q >= p; q--)
@ -3533,7 +3542,7 @@ void lj_asm_patchexit(jit_State *J, Trace *T, ExitNo exitno, MCode *target)
MCode *pe = p+len-6;
uint32_t stateaddr = u32ptr(&J2G(J)->vmstate);
if (len > 5 && p[len-5] == XI_JMP && p+len-6 + *(int32_t *)(p+len-4) == px)
*(int32_t *)(p+len-4) = (int32_t)(target - (p+len));
*(int32_t *)(p+len-4) = jmprel(p+len, target);
/* Do not patch parent exit for a stack check. Skip beyond vmstate update. */
for (; p < pe; p++)
if (*(uint32_t *)(p+(LJ_64 ? 3 : 2)) == stateaddr && p[0] == XI_MOVmi) {
@ -3543,7 +3552,7 @@ void lj_asm_patchexit(jit_State *J, Trace *T, ExitNo exitno, MCode *target)
lua_assert(p < pe);
for (; p < pe; p++) {
if ((*(uint16_t *)p & 0xf0ff) == 0x800f && p + *(int32_t *)(p+2) == px) {
*(int32_t *)(p+2) = (int32_t)(target - (p+6));
*(int32_t *)(p+2) = jmprel(p+6, target);
p += 5;
}
}