[mips] Implement custom MCELFStreamer.

This allows us to insert some hooks before emitting data into an actual object file.
For example, we can capture the register usage for a translation unit by overriding
the EmitInstruction method. The register usage information is needed to generate
.reginfo and .Mips.options ELF sections.
    
No functional changes.
    
Differential Revision: http://llvm-reviews.chandlerc.com/D3129

llvm-svn: 204917

1 files changed, 43 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
new file mode 100644
index 00000000000..aea9440ee7a
--- /dev/null
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
@@ -0,0 +1,43 @@
+//===-------- MipsELFStreamer.h - ELF Object Output -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a custom MCELFStreamer which allows us to insert some hooks before
+// emitting data into an actual object file.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MIPSELFSTREAMER_H
+#define MIPSELFSTREAMER_H
+
+#include "llvm/MC/MCELFStreamer.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+class MCAsmBackend;
+class MCCodeEmitter;
+class MCContext;
+class MCSubtargetInfo;
+
+class MipsELFStreamer : public MCELFStreamer {
+  const MCSubtargetInfo &STI;
+
+public:
+  MipsELFStreamer(MCContext &Context, MCAsmBackend &MAB, raw_ostream &OS,
+                  MCCodeEmitter *Emitter, const MCSubtargetInfo &STI)
+      : MCELFStreamer(Context, MAB, OS, Emitter), STI(STI) {}
+
+  virtual ~MipsELFStreamer() {}
+};
+
+MCELFStreamer *createMipsELFStreamer(MCContext &Context, MCAsmBackend &MAB,
+                                     raw_ostream &OS, MCCodeEmitter *Emitter,
+                                     const MCSubtargetInfo &STI, bool RelaxAll,
+                                     bool NoExecStack);
+} // namespace llvm.
+#endif