From 7381b620358c2561e8690149f1d25828fdad6675 Mon Sep 17 00:00:00 2001

From: Mike Pall <mike>

Date: Wed, 7 Jun 2017 19:16:22 +0200

Subject: [PATCH 03/72] MIPS: Use precise search for exit jump patching.

Contributed by Djordje Kovacevic and Stefan Pejic.

---

 src/lj_asm_mips.h | 6 +++++-

 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/lj_asm_mips.h b/src/lj_asm_mips.h

index 03270cc..d0a1ca5 100644

--- a/src/lj_asm_mips.h

+++ b/src/lj_asm_mips.h

@@ -1933,7 +1933,11 @@ void lj_asm_patchexit(jit_State *J, GCtrace *T, ExitNo exitno, MCode *target)

   MCode tjump = MIPSI_J|(((uintptr_t)target>>2)&0x03ffffffu);

   for (p++; p < pe; p++) {

     if (*p == exitload) {  /* Look for load of exit number. */

-      if (((p[-1] ^ (px-p)) & 0xffffu) == 0) {  /* Look for exitstub branch. */

+      /* Look for exitstub branch. Yes, this covers all used branch variants. */

+      if (((p[-1] ^ (px-p)) & 0xffffu) == 0 &&

+	  ((p[-1] & 0xf0000000u) == MIPSI_BEQ ||

+	   (p[-1] & 0xfc1e0000u) == MIPSI_BLTZ ||

+	   (p[-1] & 0xffe00000u) == MIPSI_BC1F)) {

 	ptrdiff_t delta = target - p;

 	if (((delta + 0x8000) >> 16) == 0) {  /* Patch in-range branch. */

 	patchbranch:

-- 

2.20.1