Subzero: Add sandboxing for x86-32.

src/assembler_ia32.h

Index: src/assembler_ia32.h
diff --git a/src/assembler_ia32.h b/src/assembler_ia32.h
index 3e73574391a4b003c280dfbaec5bf6b5b9e0e933..06a601eb0d4296e27b320598454aeb087a0fe00e 100644
--- a/src/assembler_ia32.h
+++ b/src/assembler_ia32.h
@@ -325,6 +325,8 @@ private:
 
   intptr_t position_;
   intptr_t num_unresolved_;
+  // TODO(stichnot,jvoung): Can this instead be
+  // llvm::SmallVector<intptr_t, kMaxUnresolvedBranches> ?
   intptr_t unresolved_near_positions_[kMaxUnresolvedBranches];
 
   friend class AssemblerX86;
@@ -354,6 +356,15 @@ public:
     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);