Fixed crashes exposed though fuzzing.

src/ia32/full-codegen-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 3422 matching lines @@
     __ jmp(&done);
   }
 
   __ bind(&not_date_object);
   __ CallRuntime(Runtime::kThrowNotDateError, 0);
   __ bind(&done);
   context()->Plug(result);
 }
 
 
-void FullCodeGenerator::EmitSeqStringSetCharCheck(Register string,
-                                                  Register index,
-                                                  Register value,
-                                                  uint32_t encoding_mask) {
-  __ test(index, Immediate(kSmiTagMask));
-  __ Check(zero, kNonSmiIndex);
-  __ test(value, Immediate(kSmiTagMask));
-  __ Check(zero, kNonSmiValue);
-
-  __ cmp(index, FieldOperand(string, String::kLengthOffset));
-  __ Check(less, kIndexIsTooLarge);
-
-  __ cmp(index, Immediate(Smi::FromInt(0)));
-  __ Check(greater_equal, kIndexIsNegative);
-
-  __ push(value);
-  __ mov(value, FieldOperand(string, HeapObject::kMapOffset));
-  __ movzx_b(value, FieldOperand(value, Map::kInstanceTypeOffset));
-
-  __ and_(value, Immediate(kStringRepresentationMask | kStringEncodingMask));
-  __ cmp(value, Immediate(encoding_mask));
-  __ Check(equal, kUnexpectedStringType);
-  __ pop(value);
-}
-
-
 void FullCodeGenerator::EmitOneByteSeqStringSetChar(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT_EQ(3, args->length());
 
   Register string = eax;
   Register index = ebx;
   Register value = ecx;
 
   VisitForStackValue(args->at(1));  // index
   VisitForStackValue(args->at(2));  // value
   __ pop(value);
   __ pop(index);
   VisitForAccumulatorValue(args->at(0));  // string
 
-
   if (FLAG_debug_code) {
-    static const uint32_t one_byte_seq_type = kSeqStringTag | kOneByteStringTag;
-    EmitSeqStringSetCharCheck(string, index, value, one_byte_seq_type);
+    __ test(value, Immediate(kSmiTagMask));
+    __ ThrowIf(not_zero, kNonSmiValue);
+    __ test(index, Immediate(kSmiTagMask));
+    __ ThrowIf(not_zero, kNonSmiValue);
   }
 
   __ SmiUntag(value);
   __ SmiUntag(index);
+
+  if (FLAG_debug_code) {
+    static const uint32_t one_byte_seq_type = kSeqStringTag | kOneByteStringTag;
+    __ EmitSeqStringSetCharCheck(string, index, value, one_byte_seq_type);
+  }
+
   __ mov_b(FieldOperand(string, index, times_1, SeqOneByteString::kHeaderSize),
            value);
   context()->Plug(string);
 }
 
 
 void FullCodeGenerator::EmitTwoByteSeqStringSetChar(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT_EQ(3, args->length());
 
   Register string = eax;
   Register index = ebx;
   Register value = ecx;
 
   VisitForStackValue(args->at(1));  // index
   VisitForStackValue(args->at(2));  // value
   __ pop(value);
   __ pop(index);
   VisitForAccumulatorValue(args->at(0));  // string
 
   if (FLAG_debug_code) {
+    __ test(value, Immediate(kSmiTagMask));
+    __ ThrowIf(not_zero, kNonSmiValue);
+    __ test(index, Immediate(kSmiTagMask));
+    __ ThrowIf(not_zero, kNonSmiValue);
+    __ SmiUntag(index);
     static const uint32_t two_byte_seq_type = kSeqStringTag | kTwoByteStringTag;
-    EmitSeqStringSetCharCheck(string, index, value, two_byte_seq_type);
+    __ EmitSeqStringSetCharCheck(string, index, value, two_byte_seq_type);
+    __ SmiTag(index);
   }
 
   __ SmiUntag(value);
   // No need to untag a smi for two-byte addressing.
   __ mov_w(FieldOperand(string, index, times_1, SeqTwoByteString::kHeaderSize),
            value);
   context()->Plug(string);
 }
 
 
@@ skipping 1444 matching lines @@
 
   ASSERT_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
             Assembler::target_address_at(call_target_address));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32