Subzero: Add sandboxing for x86-32.

src/assembler_ia32.h

 //===- subzero/src/assembler_ia32.h - Assembler for x86-32 ------*- C++ -*-===//
 // 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.
 //
 // Modified by the Subzero authors.
 //
 //===----------------------------------------------------------------------===//
 //
 //                        The Subzero Code Generator
@@ skipping 336 matching lines @@
 
   void alignFunction() override;
 
   SizeT getBundleAlignLog2Bytes() const override { return 5; }
 
   llvm::ArrayRef<uint8_t> getNonExecBundlePadding() const override {
     static const uint8_t Padding[] = {0xF4};
     return llvm::ArrayRef<uint8_t>(Padding, 1);
   }
 
+  void padWithNop(intptr_t Padding) override {
+    while (Padding > MAX_NOP_SIZE) {
+      nop(MAX_NOP_SIZE);
+      Padding -= MAX_NOP_SIZE;
+    }
+    if (Padding)
+      nop(Padding);
+  }
+
   Label *GetOrCreateCfgNodeLabel(SizeT NodeNumber);
   void BindCfgNodeLabel(SizeT NodeNumber) override;
   Label *GetOrCreateLocalLabel(SizeT Number);
   void BindLocalLabel(SizeT Number);
 
   bool fixupIsPCRel(FixupKind Kind) const override {
     // Currently assuming this is the only PC-rel relocation type used.
     return Kind == llvm::ELF::R_386_PC32;
   }
 
@@ skipping 499 matching lines @@
 inline void AssemblerX86::EmitFixup(AssemblerFixup *fixup) {
   buffer_.EmitFixup(fixup);
 }
 
 inline void AssemblerX86::EmitOperandSizeOverride() { EmitUint8(0x66); }
 
 } // end of namespace x86
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ASSEMBLER_IA32_H_