Handle OOM failures correctly in the CEntryStub when embedders set V8::IgnoreOutOfMemoryException()

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index b43d583028776b4eb5c3ada584915c8f19dbc7b5..349adc512e1c2b95be6a1c8312ce518b55f80bd1 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -4152,12 +4152,19 @@ void CEntryStub::GenerateCore(MacroAssembler* masm,
   // Special handling of out of memory exceptions.
   JumpIfOOM(masm, rax, kScratchRegister, throw_out_of_memory_exception);
 
-  // Retrieve the pending exception and clear the variable.
+  // Retrieve the pending exception.
   ExternalReference pending_exception_address(
       Isolate::kPendingExceptionAddress, masm->isolate());
   Operand pending_exception_operand =
       masm->ExternalOperand(pending_exception_address);
   __ movq(rax, pending_exception_operand);
+
+  // See if we just retrieved an OOM exception.
+  JumpIfOOM(masm, rax, kScratchRegister, throw_out_of_memory_exception);
+
+  // Clear the pending exception.
+  pending_exception_operand =
+      masm->ExternalOperand(pending_exception_address);

[Michael Starzinger, 2013/04/16 12:09:45]

nit: Do we really need to recompute the operand here? Can't we just use the same
operand twice?

[Jakob Kummerow, 2013/04/16 12:13:11]

Yes, we need to, because the call to masm->ExternalOperand() also emits a move
instruction that modifies kScratchRegister. Obvious, no? :-P

   __ LoadRoot(rdx, Heap::kTheHoleValueRootIndex);
   __ movq(pending_exception_operand, rdx);