Subzero: Update tests and build scripts for sandboxing.

src/IceInstX8632.h

Index: src/IceInstX8632.h
diff --git a/src/IceInstX8632.h b/src/IceInstX8632.h
index ed4924f135783200490d2421ca95122858775bf2..cfb2f66ce56adfb579c619c61dd39a89781a98ab 100644
--- a/src/IceInstX8632.h
+++ b/src/IceInstX8632.h
@@ -1031,6 +1031,26 @@ protected:
     // with optimizations.
     HasSideEffects = Locked;
   }
+  // emitPrefix() and emitSuffix() are a workaround for an apparent
+  // llvm-mc bug in which "lock" is considered a separate instruction
+  // and may be placed in a different bundle from the instruction
+  // being locked, e.g.:
+  //   1e: lock nop
+  //   20: cmpxchg ...

[jvoung (off chromium), 2015/02/23 17:58:36]

Weird, I thought it would have been fixed by:

https://codereview.chromium.org/569773002/diff/140001/test/MC/X86/AlignedBund...

This is with "nacl" as the OS in the target triple?

[Jim Stichnoth, 2015/02/23 21:38:19]

Aha!  The szbuild.py was running llvm-mc with just -target=x86, but it should
also use -triple=i686 or -triple=i686-nacl.  So I can undo that workaround.

+  // The workaround is to emit an explicit bundle_lock/bundle_unlock
+  // for instructions with a lock prefix.
+  void emitPrefix(Ostream &Str) const {
+    if (!ALLOW_DUMP)
+      return;
+    if (Locked)
+      Str << "\t.bundle_lock\n";
+  }
+  void emitSuffix(Ostream &Str) const {
+    if (!ALLOW_DUMP)
+      return;
+    if (Locked)
+      Str << "\n\t.bundle_unlock";
+  }
   ~InstX8632Lockable() override {}
 };