MIPS: Critical fix for label binding in RegExp engine when trampoline is emitted.

TEST=mjsunit/regress/regress-crbug-178790

BUG=

Review URL: https://codereview.chromium.org/12939010
Patch from Dusan Milosavljevic <Dusan.Milosavljevic@rt-rk.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14013 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/assembler-mips.cc

@@ -490,7 +490,6 @@ bool Assembler::IsBranch(Instr instr) {
   uint32_t opcode   = GetOpcodeField(instr);
   uint32_t rt_field = GetRtField(instr);
   uint32_t rs_field = GetRsField(instr);
-  uint32_t label_constant = GetLabelConst(instr);
   // Checks if the instruction is a branch.
   return opcode == BEQ ||
       opcode == BNE ||
@@ -502,10 +501,13 @@ bool Assembler::IsBranch(Instr instr) {
       opcode == BGTZL ||
       (opcode == REGIMM && (rt_field == BLTZ || rt_field == BGEZ ||
                             rt_field == BLTZAL || rt_field == BGEZAL)) ||
-      (opcode == COP1 && rs_field == BC1) ||  // Coprocessor branch.
-      label_constant == 0;  // Emitted label const in reg-exp engine.
+      (opcode == COP1 && rs_field == BC1);  // Coprocessor branch.
 }
 
+bool Assembler::IsEmittedConstant(Instr instr) {
+  uint32_t label_constant = GetLabelConst(instr);
+  return label_constant == 0;  // Emitted label const in reg-exp engine.
+}
 
 bool Assembler::IsBeq(Instr instr) {
   return GetOpcodeField(instr) == BEQ;
@@ -796,7 +798,7 @@ void Assembler::bind_to(Label* L, int pos) {
       }
       target_at_put(fixup_pos, pos);
     } else {
-      ASSERT(IsJ(instr) || IsLui(instr));
+      ASSERT(IsJ(instr) || IsLui(instr) || IsEmittedConstant(instr));
       target_at_put(fixup_pos, pos);
     }
   }

src/mips/assembler-mips.h

@@ -942,6 +942,7 @@ class Assembler : public AssemblerBase {
   static Instr SetAddImmediateOffset(Instr instr, int16_t offset);
 
   static bool IsAndImmediate(Instr instr);
+  static bool IsEmittedConstant(Instr instr);
 
   void CheckTrampolinePool();
 

src/mips/macro-assembler-mips.cc

@@ -1108,6 +1108,7 @@ void MacroAssembler::BranchF(Label* target,
                              FPURegister cmp1,
                              FPURegister cmp2,
                              BranchDelaySlot bd) {
+  BlockTrampolinePoolScope block_trampoline_pool(this);
   if (cc == al) {
     Branch(bd, target);
     return;
@@ -1700,6 +1701,7 @@ void MacroAssembler::BranchShort(int16_t offset, Condition cond, Register rs,
   if (rt.is_reg()) {
     // NOTE: 'at' can be clobbered by Branch but it is legal to use it as rs or
     // rt.
+    BlockTrampolinePoolScope block_trampoline_pool(this);
     r2 = rt.rm_;
     switch (cond) {
       case cc_always:
@@ -1785,6 +1787,7 @@ void MacroAssembler::BranchShort(int16_t offset, Condition cond, Register rs,
     // Be careful to always use shifted_branch_offset only just before the
     // branch instruction, as the location will be remember for patching the
     // target.
+    BlockTrampolinePoolScope block_trampoline_pool(this);
     switch (cond) {
       case cc_always:
         b(offset);
@@ -1929,6 +1932,7 @@ void MacroAssembler::BranchShort(Label* L, Condition cond, Register rs,
   Register r2 = no_reg;
   Register scratch = at;
   if (rt.is_reg()) {
+    BlockTrampolinePoolScope block_trampoline_pool(this);
     r2 = rt.rm_;
     // Be careful to always use shifted_branch_offset only just before the
     // branch instruction, as the location will be remember for patching the
@@ -2035,6 +2039,7 @@ void MacroAssembler::BranchShort(Label* L, Condition cond, Register rs,
     // Be careful to always use shifted_branch_offset only just before the
     // branch instruction, as the location will be remember for patching the
     // target.
+    BlockTrampolinePoolScope block_trampoline_pool(this);
     switch (cond) {
       case cc_always:
         offset = shifted_branch_offset(L, false);
@@ -2271,6 +2276,8 @@ void MacroAssembler::BranchAndLinkShort(int16_t offset, Condition cond,
     li(r2, rt);
   }
 
+  {
+    BlockTrampolinePoolScope block_trampoline_pool(this);
     switch (cond) {
       case cc_always:
         bal(offset);
@@ -2333,6 +2340,7 @@ void MacroAssembler::BranchAndLinkShort(int16_t offset, Condition cond,
       default:
         UNREACHABLE();
     }
+  }
   // Emit a nop in the branch delay slot if required.
   if (bdslot == PROTECT)
     nop();
@@ -2363,6 +2371,8 @@ void MacroAssembler::BranchAndLinkShort(Label* L, Condition cond, Register rs,
     li(r2, rt);
   }
 
+  {
+    BlockTrampolinePoolScope block_trampoline_pool(this);
     switch (cond) {
       case cc_always:
         offset = shifted_branch_offset(L, false);
@@ -2436,7 +2446,7 @@ void MacroAssembler::BranchAndLinkShort(Label* L, Condition cond, Register rs,
       default:
         UNREACHABLE();
     }
-
+  }
   // Check that offset could actually hold on an int16_t.
   ASSERT(is_int16(offset));
 

src/mips/regexp-macro-assembler-mips.cc

@@ -1005,6 +1005,7 @@ void RegExpMacroAssemblerMIPS::PushBacktrack(Label* label) {
     int target = label->pos();
     __ li(a0, Operand(target + Code::kHeaderSize - kHeapObjectTag));
   } else {
+    Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm_);
     Label after_constant;
     __ Branch(&after_constant);
     int offset = masm_->pc_offset();