From 2bc63bb6affdb378c1698bd0f97bacb286a61a6f Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Wed, 19 Feb 2014 17:09:22 +0100
Subject: [PATCH] Prevent BASE register coalescing if parent uses IR_RETF.

---
 src/lj_asm_arm.h  | 7 +++++--
 src/lj_asm_mips.h | 5 +++--
 src/lj_asm_ppc.h  | 5 +++--
 src/lj_asm_x86.h  | 5 +++--
 4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/lj_asm_arm.h b/src/lj_asm_arm.h
index 0ab3a567..72f205d9 100644
--- a/src/lj_asm_arm.h
+++ b/src/lj_asm_arm.h
@@ -493,6 +493,7 @@ static void asm_retf(ASMState *as, IRIns *ir)
   int32_t delta = 1+bc_a(*((const BCIns *)pc - 1));
   as->topslot -= (BCReg)delta;
   if ((int32_t)as->topslot < 0) as->topslot = 0;
+  irt_setmark(IR(REF_BASE)->t);  /* Children must not coalesce with BASE reg. */
   /* Need to force a spill on REF_BASE now to update the stack slot. */
   emit_lso(as, ARMI_STR, base, RID_SP, ra_spill(as, IR(REF_BASE)));
   emit_setgl(as, base, jit_base);
@@ -2102,7 +2103,8 @@ static void asm_head_root_base(ASMState *as)
   IRIns *ir;
   asm_head_lreg(as);
   ir = IR(REF_BASE);
-  if (ra_hasreg(ir->r) && rset_test(as->modset, ir->r)) ra_spill(as, ir);
+  if (ra_hasreg(ir->r) && (rset_test(as->modset, ir->r) || irt_ismarked(ir->t)))
+    ra_spill(as, ir);
   ra_destreg(as, ir, RID_BASE);
 }
 
@@ -2112,7 +2114,8 @@ static RegSet asm_head_side_base(ASMState *as, IRIns *irp, RegSet allow)
   IRIns *ir;
   asm_head_lreg(as);
   ir = IR(REF_BASE);
-  if (ra_hasreg(ir->r) && rset_test(as->modset, ir->r)) ra_spill(as, ir);
+  if (ra_hasreg(ir->r) && (rset_test(as->modset, ir->r) || irt_ismarked(ir->t)))
+    ra_spill(as, ir);
   if (ra_hasspill(irp->s)) {
     rset_clear(allow, ra_dest(as, ir, allow));
   } else {
diff --git a/src/lj_asm_mips.h b/src/lj_asm_mips.h
index f5b0bab6..e5c67b53 100644
--- a/src/lj_asm_mips.h
+++ b/src/lj_asm_mips.h
@@ -394,6 +394,7 @@ static void asm_retf(ASMState *as, IRIns *ir)
   int32_t delta = 1+bc_a(*((const BCIns *)pc - 1));
   as->topslot -= (BCReg)delta;
   if ((int32_t)as->topslot < 0) as->topslot = 0;
+  irt_setmark(IR(REF_BASE)->t);  /* Children must not coalesce with BASE reg. */
   emit_setgl(as, base, jit_base);
   emit_addptr(as, base, -8*delta);
   asm_guard(as, MIPSI_BNE, RID_TMP,
@@ -1723,7 +1724,7 @@ static void asm_head_root_base(ASMState *as)
   if (as->loopinv) as->mctop--;
   if (ra_hasreg(r)) {
     ra_free(as, r);
-    if (rset_test(as->modset, r))
+    if (rset_test(as->modset, r) || irt_ismarked(ir->t))
       ir->r = RID_INIT;  /* No inheritance for modified BASE register. */
     if (r != RID_BASE)
       emit_move(as, r, RID_BASE);
@@ -1738,7 +1739,7 @@ static RegSet asm_head_side_base(ASMState *as, IRIns *irp, RegSet allow)
   if (as->loopinv) as->mctop--;
   if (ra_hasreg(r)) {
     ra_free(as, r);
-    if (rset_test(as->modset, r))
+    if (rset_test(as->modset, r) || irt_ismarked(ir->t))
       ir->r = RID_INIT;  /* No inheritance for modified BASE register. */
     if (irp->r == r) {
       rset_clear(allow, r);  /* Mark same BASE register as coalesced. */
diff --git a/src/lj_asm_ppc.h b/src/lj_asm_ppc.h
index 57fd2513..e1a496a7 100644
--- a/src/lj_asm_ppc.h
+++ b/src/lj_asm_ppc.h
@@ -381,6 +381,7 @@ static void asm_retf(ASMState *as, IRIns *ir)
   int32_t delta = 1+bc_a(*((const BCIns *)pc - 1));
   as->topslot -= (BCReg)delta;
   if ((int32_t)as->topslot < 0) as->topslot = 0;
+  irt_setmark(IR(REF_BASE)->t);  /* Children must not coalesce with BASE reg. */
   emit_setgl(as, base, jit_base);
   emit_addptr(as, base, -8*delta);
   asm_guardcc(as, CC_NE);
@@ -1901,7 +1902,7 @@ static void asm_head_root_base(ASMState *as)
   Reg r = ir->r;
   if (ra_hasreg(r)) {
     ra_free(as, r);
-    if (rset_test(as->modset, r))
+    if (rset_test(as->modset, r) || irt_ismarked(ir->t))
       ir->r = RID_INIT;  /* No inheritance for modified BASE register. */
     if (r != RID_BASE)
       emit_mr(as, r, RID_BASE);
@@ -1915,7 +1916,7 @@ static RegSet asm_head_side_base(ASMState *as, IRIns *irp, RegSet allow)
   Reg r = ir->r;
   if (ra_hasreg(r)) {
     ra_free(as, r);
-    if (rset_test(as->modset, r))
+    if (rset_test(as->modset, r) || irt_ismarked(ir->t))
       ir->r = RID_INIT;  /* No inheritance for modified BASE register. */
     if (irp->r == r) {
       rset_clear(allow, r);  /* Mark same BASE register as coalesced. */
diff --git a/src/lj_asm_x86.h b/src/lj_asm_x86.h
index 98a08d97..fda911e5 100644
--- a/src/lj_asm_x86.h
+++ b/src/lj_asm_x86.h
@@ -647,6 +647,7 @@ static void asm_retf(ASMState *as, IRIns *ir)
   int32_t delta = 1+bc_a(*((const BCIns *)pc - 1));
   as->topslot -= (BCReg)delta;
   if ((int32_t)as->topslot < 0) as->topslot = 0;
+  irt_setmark(IR(REF_BASE)->t);  /* Children must not coalesce with BASE reg. */
   emit_setgl(as, base, jit_base);
   emit_addptr(as, base, -8*delta);
   asm_guardcc(as, CC_NE);
@@ -2481,7 +2482,7 @@ static void asm_head_root_base(ASMState *as)
   Reg r = ir->r;
   if (ra_hasreg(r)) {
     ra_free(as, r);
-    if (rset_test(as->modset, r))
+    if (rset_test(as->modset, r) || irt_ismarked(ir->t))
       ir->r = RID_INIT;  /* No inheritance for modified BASE register. */
     if (r != RID_BASE)
       emit_rr(as, XO_MOV, r, RID_BASE);
@@ -2495,7 +2496,7 @@ static RegSet asm_head_side_base(ASMState *as, IRIns *irp, RegSet allow)
   Reg r = ir->r;
   if (ra_hasreg(r)) {
     ra_free(as, r);
-    if (rset_test(as->modset, r))
+    if (rset_test(as->modset, r) || irt_ismarked(ir->t))
       ir->r = RID_INIT;  /* No inheritance for modified BASE register. */
     if (irp->r == r) {
       rset_clear(allow, r);  /* Mark same BASE register as coalesced. */