Subzero: Add sandboxing for x86-32.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index dfd8cd123bfdc09418d095c80666b1be53c322f8..ecdda3781db41994e3ece9670a47e799a4cddcf3 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -115,6 +115,11 @@ public:
 
   const FixupRefList &fixups() const { return fixups_; }
 
+  void setSize(intptr_t NewSize) {
+    assert(NewSize < Size());
+    cursor_ = contents_ + NewSize;
+  }
+
 private:
   // The limit is set to kMinimumGap bytes before the end of the data area.
   // This leaves enough space for the longest possible instruction and allows
@@ -194,6 +199,11 @@ public:
   void setInternal(bool Internal) { IsInternal = Internal; }
   const IceString &getFunctionName() { return FunctionName; }
   void setFunctionName(const IceString &NewName) { FunctionName = NewName; }
+  intptr_t getBufferSize() const { return buffer_.Size(); }
+  // Roll back to a (smaller) size.
+  void setBufferSize(intptr_t NewSize) { buffer_.setSize(NewSize); }
+  // Add nop padding of a particular width.
+  virtual void padWithNop(intptr_t Padding) = 0;
 
 private:
   ArenaAllocator<32 * 1024> Allocator;