Fixed crashes exposed though fuzzing.

src/ia32/lithium-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 1874 matching lines @@
 }
 
 
 LInstruction* LChunkBuilder::DoSeqStringGetChar(HSeqStringGetChar* instr) {
   LOperand* string = UseRegisterAtStart(instr->string());
   LOperand* index = UseRegisterOrConstantAtStart(instr->index());
   return DefineAsRegister(new(zone()) LSeqStringGetChar(string, index));
 }
 
 
+LOperand* LChunkBuilder::GetSeqStringSetCharOperand(HSeqStringSetChar* instr) {
+  if (instr->encoding() == String::ONE_BYTE_ENCODING) {
+    if (FLAG_debug_code) {
+      return UseFixed(instr->value(), eax);
+    } else {
+      return UseFixedOrConstant(instr->value(), eax);
+    }
+  } else {
+    if (FLAG_debug_code) {
+      return UseRegisterAtStart(instr->value());
+    } else {
+      return UseRegisterOrConstantAtStart(instr->value());
+    }
+  }
+}
+
+
 LInstruction* LChunkBuilder::DoSeqStringSetChar(HSeqStringSetChar* instr) {
   LOperand* string = UseRegisterAtStart(instr->string());
-  LOperand* index = UseRegisterOrConstantAtStart(instr->index());
-  LOperand* value = (instr->encoding() == String::ONE_BYTE_ENCODING)
-      ? UseFixedOrConstant(instr->value(), eax)
-      : UseRegisterOrConstantAtStart(instr->value());
-  return new(zone()) LSeqStringSetChar(string, index, value);
+  LOperand* index = FLAG_debug_code
+      ? UseRegisterAtStart(instr->index())
+      : UseRegisterOrConstantAtStart(instr->index());
+  LOperand* value = GetSeqStringSetCharOperand(instr);
+  LOperand* context = FLAG_debug_code ? UseFixed(instr->context(), esi) : NULL;
+  LInstruction* result = new(zone()) LSeqStringSetChar(context, string,
+                                                       index, value);
+  if (FLAG_debug_code) {
+    result = MarkAsCall(result, instr);
+  }
+  return result;
 }
 
 
 LInstruction* LChunkBuilder::DoBoundsCheck(HBoundsCheck* instr) {
   return AssignEnvironment(new(zone()) LBoundsCheck(
       UseRegisterOrConstantAtStart(instr->index()),
       UseAtStart(instr->length())));
 }
 
 
@@ skipping 855 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32