Add support for tracking down leak of the hole value.

src/ia32/codegen-ia32.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7573 matching lines @@
   // Call C function.
   __ mov(Operand(esp, 0 * kPointerSize), edi);  // argc.
   __ mov(Operand(esp, 1 * kPointerSize), esi);  // argv.
   __ call(Operand(ebx));
   // Result is in eax or edx:eax - do not destroy these registers!
 
   if (always_allocate_scope) {
     __ dec(Operand::StaticVariable(scope_depth));
   }
 
+  // Make sure we're not trying to return 'the hole' from the runtime
+  // call as this may lead to crashes in the IC code later.
+  if (FLAG_debug_code) {
+    Label okay;
+    __ cmp(Operand(eax), Immediate(Factory::the_hole_value()));

[Kevin Millikin (Chromium), 2009/07/13 09:10:07]

There is a cmp(Register, Handle<Object>) assembler instruction on IA32.  Same
encoding, but reads better at the call site.

+    __ j(not_equal, &okay);
+    __ int3();
+    __ bind(&okay);
+  }
+
   // Check for failure result.
   Label failure_returned;
   ASSERT(((kFailureTag + 1) & kFailureTagMask) == 0);
   __ lea(ecx, Operand(eax, 1));
   // Lower 2 bits of ecx are 0 iff eax has failure tag.
   __ test(ecx, Immediate(kFailureTagMask));
   __ j(zero, &failure_returned, not_taken);
 
   // Exit the JavaScript to C++ exit frame.
   __ LeaveExitFrame(frame_type);
@@ skipping 307 matching lines @@
 
 int CompareStub::MinorKey() {
   // Encode the two parameters in a unique 16 bit value.
   ASSERT(static_cast<unsigned>(cc_) < (1 << 15));
   return (static_cast<unsigned>(cc_) << 1) | (strict_ ? 1 : 0);
 }
 
 #undef __
 
 } }  // namespace v8::internal