Fail early when re-entering code that has been patched for lazy deopt

src/ia32/deoptimizer-ia32.cc

 // Copyright 2012 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 98 matching lines @@
              pos_before - reloc_info_writer.pos());
     }
     // Replace relocation information on the code object.
     code->set_relocation_info(*new_reloc);
   }
 }
 
 
 void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
   Address code_start_address = code->instruction_start();
+
+  if (FLAG_zap_code_space) {
+    // Fail hard and early if we enter this code object again.
+    byte* pointer = code->FindCodeAgeSequence();
+    if (pointer != NULL) {
+      pointer += kNoCodeAgeSequenceLength;
+    } else {
+      pointer = code->instruction_start();
+    }
+    CodePatcher patcher(pointer, 1);
+    patcher.masm()->int3();
+
+    DeoptimizationInputData* data =
+        DeoptimizationInputData::cast(code->deoptimization_data());
+    int osr_offset = data->OsrPcOffset()->value();
+    if (osr_offset > 0) {
+      CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
+      osr_patcher.masm()->int3();
+    }
+  }
+
   // We will overwrite the code's relocation info in-place. Relocation info
   // is written backward. The relocation info is the payload of a byte
   // array.  Later on we will slide this to the start of the byte array and
   // create a filler object in the remaining space.
   ByteArray* reloc_info = code->relocation_info();
   Address reloc_end_address = reloc_info->address() + reloc_info->Size();
   RelocInfoWriter reloc_info_writer(reloc_end_address, code_start_address);
 
   // For each LLazyBailout instruction insert a call to the corresponding
   // deoptimization entry.
@@ skipping 310 matching lines @@
   SetFrameSlot(offset, value);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32