Introduce Target::createNullTargetStreamer and use it from IRObjectFile.

A null MCTargetStreamer allows IRObjectFile to ignore target-specific
directives. Previously we were crashing.

Differential Revision: http://reviews.llvm.org/D7711

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229797 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/TargetRegistry.h

@@ -47,6 +47,7 @@ namespace llvm {
   class MCRelocationInfo;
   class MCTargetAsmParser;
   class MCTargetOptions;
+  class MCTargetStreamer;
   class TargetMachine;
   class TargetOptions;
   class raw_ostream;
@@ -139,6 +140,7 @@ namespace llvm {
                                              MCAsmBackend *TAB,
                                              bool ShowInst);
     typedef MCStreamer *(*NullStreamerCtorTy)(MCContext &Ctx);
+    typedef MCTargetStreamer *(*NullTargetStreamerCtorTy)(MCStreamer &S);
     typedef MCRelocationInfo *(*MCRelocationInfoCtorTy)(StringRef TT,
                                                         MCContext &Ctx);
     typedef MCSymbolizer *(*MCSymbolizerCtorTy)(
@@ -227,6 +229,10 @@ namespace llvm {
     /// (default = llvm::createNullStreamer).
     NullStreamerCtorTy NullStreamerCtorFn;
 
+    /// Construction function for this target's null TargetStreamer, if
+    /// registered (default = nullptr).
+    NullTargetStreamerCtorTy NullTargetStreamerCtorFn;
+
     /// MCRelocationInfoCtorFn - Construction function for this target's
     /// MCRelocationInfo, if registered (default = llvm::createMCRelocationInfo)
     MCRelocationInfoCtorTy MCRelocationInfoCtorFn;
@@ -453,6 +459,12 @@ namespace llvm {
       return llvm::createNullStreamer(Ctx);
     }
 
+    MCTargetStreamer *createNullTargetStreamer(MCStreamer &S) const {
+      if (NullTargetStreamerCtorFn)
+        return NullTargetStreamerCtorFn(S);
+      return nullptr;
+    }
+
     /// createMCRelocationInfo - Create a target specific MCRelocationInfo.
     ///
     /// \param TT The target triple.
@@ -783,6 +795,11 @@ namespace llvm {
       T.NullStreamerCtorFn = Fn;
     }
 
+    static void
+    RegisterNullTargetStreamer(Target &T, Target::NullTargetStreamerCtorTy Fn) {
+      T.NullTargetStreamerCtorFn = Fn;
+    }
+
     /// RegisterMCRelocationInfo - Register an MCRelocationInfo
     /// implementation for the given target.
     ///

lib/Object/IRObjectFile.cpp

@@ -73,6 +73,7 @@ IRObjectFile::IRObjectFile(MemoryBufferRef Object, std::unique_ptr<Module> Mod)
   MCContext MCCtx(MAI.get(), MRI.get(), &MOFI);
   MOFI.InitMCObjectFileInfo(Triple, Reloc::Default, CodeModel::Default, MCCtx);
   std::unique_ptr<RecordStreamer> Streamer(new RecordStreamer(MCCtx));
+  T->createNullTargetStreamer(*Streamer);
 
   std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
   SourceMgr SrcMgr;

lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp

@@ -1360,6 +1360,10 @@ MCStreamer *createARMNullStreamer(MCContext &Ctx) {
   return S;
 }
 
+MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
+  return new ARMTargetStreamer(S);
+}
+
 MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
                                     raw_ostream &OS, MCCodeEmitter *Emitter,
                                     bool RelaxAll, bool IsThumb) {

lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp

@@ -461,6 +461,16 @@ extern "C" void LLVMInitializeARMTargetMC() {
   TargetRegistry::RegisterNullStreamer(TheThumbLETarget, createARMNullStreamer);
   TargetRegistry::RegisterNullStreamer(TheThumbBETarget, createARMNullStreamer);
 
+  // Register the null TargetStreamer.
+  TargetRegistry::RegisterNullTargetStreamer(TheARMLETarget,
+                                             createARMNullTargetStreamer);
+  TargetRegistry::RegisterNullTargetStreamer(TheARMBETarget,
+                                             createARMNullTargetStreamer);
+  TargetRegistry::RegisterNullTargetStreamer(TheThumbLETarget,
+                                             createARMNullTargetStreamer);
+  TargetRegistry::RegisterNullTargetStreamer(TheThumbBETarget,
+                                             createARMNullTargetStreamer);
+
   // Register the MCInstPrinter.
   TargetRegistry::RegisterMCInstPrinter(TheARMLETarget, createARMMCInstPrinter);
   TargetRegistry::RegisterMCInstPrinter(TheARMBETarget, createARMMCInstPrinter);

lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h

@@ -29,6 +29,7 @@ class MCRegisterInfo;
 class MCSubtargetInfo;
 class MCStreamer;
 class MCRelocationInfo;
+class MCTargetStreamer;
 class StringRef;
 class Target;
 class raw_ostream;
@@ -53,6 +54,8 @@ MCStreamer *createMCAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
 
 MCStreamer *createARMNullStreamer(MCContext &Ctx);
 
+MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S);
+
 MCCodeEmitter *createARMLEMCCodeEmitter(const MCInstrInfo &MCII,
                                         const MCRegisterInfo &MRI,
                                         const MCSubtargetInfo &STI,

test/LTO/ARM/inline-asm.ll

@@ -0,0 +1,9 @@
+; Check that we don't crash on target-specific inline asm directives.
+;
+; RUN: llvm-as < %s > %t
+; RUN: llvm-lto -o /dev/null %t -mcpu armv4t
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "armv4t-unknown-linux"
+
+module asm ".fnstart"