[mips] Implement NaCl sandboxing of indirect jumps:

  * Align targets of indirect jumps to instruction bundle boundaries (in MI layer).
  * Add masking instructions before indirect jumps (in MC layer).

Differential Revision: http://llvm-reviews.chandlerc.com/D2847


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202479 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 0 deletions

diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCNaCl.h b/lib/Target/Mips/MCTargetDesc/MipsMCNaCl.h
new file mode 100644
index 0000000000..62d67d9f3f
--- /dev/null
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCNaCl.h
@@ -0,0 +1,28 @@
+//===-- MipsMCNaCl.h - NaCl-related declarations --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MIPSMCNACL_H
+#define MIPSMCNACL_H
+
+#include "llvm/MC/MCELFStreamer.h"
+
+namespace llvm {
+
+// Log2 of the NaCl MIPS sandbox's instruction bundle size.
+static const unsigned MIPS_NACL_BUNDLE_ALIGN = 4u;
+
+// This function creates an MCELFStreamer for Mips NaCl.
+MCELFStreamer *createMipsNaClELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+                                         raw_ostream &OS,
+                                         MCCodeEmitter *Emitter,
+                                         bool RelaxAll, bool NoExecStack);
+
+}
+
+#endif