Fix an undetected Smi overflow on ARM.

runtime/vm/assembler_ia32.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 1967 matching lines @@
   }
 }
 
 
 void Assembler::PopRegister(Register r) {
   popl(r);
 }
 
 
 void Assembler::AddImmediate(Register reg, const Immediate& imm) {
-  intptr_t value = imm.value();
-  if (value > 0) {
+  const intptr_t value = imm.value();
+  if (value == 0) {
+    return;
+  }
+  if ((value > 0) || (value == kMinInt32)) {
     if (value == 1) {
       incl(reg);
-    } else if (value != 0) {
+    } else {
       addl(reg, imm);
     }
-  } else if (value < 0) {
-    value = -value;
-    if (value == 1) {
-      decl(reg);
-    } else if (value != 0) {
-      subl(reg, Immediate(value));
-    }
+  } else {
+    SubImmediate(reg, Immediate(-value));
   }
 }
 
+
+void Assembler::SubImmediate(Register reg, const Immediate& imm) {
+  const intptr_t value = imm.value();
+  if (value == 0) {
+    return;
+  }
+  if ((value > 0) || (value == kMinInt32)) {
+    if (value == 1) {
+      decl(reg);
+    } else {
+      subl(reg, imm);
+    }
+  } else {
+    AddImmediate(reg, Immediate(-value));
+  }
+}
+
 
 void Assembler::Drop(intptr_t stack_elements) {
   ASSERT(stack_elements >= 0);
   if (stack_elements > 0) {
     addl(ESP, Immediate(stack_elements * kWordSize));
   }
 }
 
 
 void Assembler::LoadObject(Register dst, const Object& object) {
@@ skipping 644 matching lines @@
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32