[PowerPC] ELFv2 MC support for .abiversion directive

ELFv2 binaries are marked by a bit in the ELF header e_flags field.
A new assembler directive .abiversion can be used to set that flag.
This patch implements support in the PowerPC MC streamers to emit the
.abiversion directive (both into assembler and ELF binary output),
as well as support in the assembler parser to parse the .abiversion
directive.

Reviewed by Hal Finkel.

llvm-svn: 213484

1 files changed, 19 insertions, 1 deletions

diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp
index 7057797cf8c..fa0e78ab3a7 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp
@@ -16,12 +16,14 @@
 #include "PPCMCAsmInfo.h"
 #include "PPCTargetStreamer.h"
 #include "llvm/MC/MCCodeGenInfo.h"
+#include "llvm/MC/MCELFStreamer.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MachineLocation.h"
+#include "llvm/Support/ELF.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/Support/TargetRegistry.h"
@@ -125,12 +127,18 @@ public:
   void emitMachine(StringRef CPU) override {
     OS << "\t.machine " << CPU << '\n';
   }
+  virtual void emitAbiVersion(int AbiVersion) override {
+    OS << "\t.abiversion " << AbiVersion << '\n';
+  }
 };
 
 class PPCTargetELFStreamer : public PPCTargetStreamer {
 public:
   PPCTargetELFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
-  void emitTCEntry(const MCSymbol &S) override {
+  MCELFStreamer &getStreamer() {
+    return static_cast<MCELFStreamer &>(Streamer);
+  }
+  virtual void emitTCEntry(const MCSymbol &S) override {
     // Creates a R_PPC64_TOC relocation
     Streamer.EmitSymbolValue(&S, 8);
   }
@@ -138,6 +146,13 @@ public:
     // FIXME: Is there anything to do in here or does this directive only
     // limit the parser?
   }
+  virtual void emitAbiVersion(int AbiVersion) override {
+    MCAssembler &MCA = getStreamer().getAssembler();
+    unsigned Flags = MCA.getELFHeaderEFlags();
+    Flags &= ~ELF::EF_PPC64_ABI;
+    Flags |= (AbiVersion & ELF::EF_PPC64_ABI);
+    MCA.setELFHeaderEFlags(Flags);
+  }
 };
 
 class PPCTargetMachOStreamer : public PPCTargetStreamer {
@@ -150,6 +165,9 @@ public:
     // FIXME: We should update the CPUType, CPUSubType in the Object file if
     // the new values are different from the defaults.
   }
+  virtual void emitAbiVersion(int AbiVersion) override {
+    llvm_unreachable("Unknown pseudo-op: .abiversion");
+  }
 };
 }