Do not leak message object beyond try-catch.

src/mips/full-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
 // Note on Mips implementation:
 //
@@ skipping 5335 matching lines @@
 
   // Store result register while executing finally block.
   __ push(a1);
 
   // Store pending message while executing finally block.
   ExternalReference pending_message_obj =
       ExternalReference::address_of_pending_message_obj(isolate());
   __ li(at, Operand(pending_message_obj));
   __ lw(a1, MemOperand(at));
   __ push(a1);
+
+  ClearPendingMessage();
 }
 
 
 void FullCodeGenerator::ExitFinallyBlock() {
   DCHECK(!result_register().is(a1));
   // Restore pending message from stack.
   __ pop(a1);
   ExternalReference pending_message_obj =
       ExternalReference::address_of_pending_message_obj(isolate());
   __ li(at, Operand(pending_message_obj));
   __ sw(a1, MemOperand(at));
 
   // Restore result register from stack.
   __ pop(a1);
 
   // Uncook return address and return.
   __ pop(result_register());
   DCHECK_EQ(1, kSmiTagSize + kSmiShiftSize);
   __ sra(a1, a1, 1);  // Un-smi-tag value.
   __ Addu(at, a1, Operand(masm_->CodeObject()));
   __ Jump(at);
 }
 
 
+void FullCodeGenerator::ClearPendingMessage() {
+  DCHECK(!result_register().is(a1));
+  ExternalReference pending_message_obj =
+      ExternalReference::address_of_pending_message_obj(isolate());
+  __ LoadRoot(a1, Heap::kTheHoleValueRootIndex);
+  __ li(at, Operand(pending_message_obj));
+  __ sw(a1, MemOperand(at));
+}
+
+
 #undef __
 
 
 void BackEdgeTable::PatchAt(Code* unoptimized_code,
                             Address pc,
                             BackEdgeState target_state,
                             Code* replacement_code) {
   static const int kInstrSize = Assembler::kInstrSize;
   Address branch_address = pc - 6 * kInstrSize;
   CodePatcher patcher(branch_address, 1);
@@ skipping 62 matching lines @@
       Assembler::target_address_at(pc_immediate_load_address)) ==
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS