[llvm-exegesis] Set up AsmTargetStreamer in readSnippets

[gchatelet]

Summary

This is a follow up on D71137 properly setting up the AsmTargetStreamer prior to AsmParser::Run call.

[mstojanovic]

LGTM, thanks for the fix!

[courbet]

llvm/tools/llvm-exegesis/lib/SnippetFile.cpp

142

Unless I'm mistaken, this InstrPrinter is leaked here.

[gchatelet]

• Address comments

llvm/tools/llvm-exegesis/lib/SnippetFile.cpp

Expected<std::vector<BenchmarkCode>> readSnippets(const LLVMState &State,
   BenchmarkCode Result;
 
   MCObjectFileInfo ObjectFileInfo;
   const TargetMachine &TM = State.getTargetMachine();
   MCContext Context(TM.getMCAsmInfo(), TM.getMCRegisterInfo(), &ObjectFileInfo);
   ObjectFileInfo.InitMCObjectFileInfo(TM.getTargetTriple(), /*PIC*/ false,
                                       Context);
   BenchmarkCodeStreamer Streamer(&Context, TM.getMCRegisterInfo(), &Result);
+
+  std::string Error;
+  raw_string_ostream ErrorStream(Error);
+  formatted_raw_ostream InstPrinterOStream(ErrorStream);
+  MCInstPrinter *const InstPrinter = TM.getTarget().createMCInstPrinter(
+      TM.getTargetTriple(), TM.getMCAsmInfo()->getAssemblerDialect(),
+      *TM.getMCAsmInfo(), *TM.getMCInstrInfo(), *TM.getMCRegisterInfo());
+  // The following call will take care of calling Streamer.setTargetStreamer.
+  TM.getTarget().createAsmTargetStreamer(Streamer, InstPrinterOStream,
+                                         InstPrinter,
+                                         TM.Options.MCOptions.AsmVerbose);
+  if (!Streamer.getTargetStreamer())
+    return make_error<Failure>("cannot create target asm streamer");
+
   const std::unique_ptr<MCAsmParser> AsmParser(
       createMCAsmParser(SM, Context, Streamer, *TM.getMCAsmInfo()));
   if (!AsmParser)
     return make_error<Failure>("cannot create asm parser");
   AsmParser->getLexer().setCommentConsumer(&Streamer);
 
   const std::unique_ptr<MCTargetAsmParser> TargetAsmParser(
       TM.getTarget().createMCAsmParser(*TM.getMCSubtargetInfo(), *AsmParser,

llvm/unittests/tools/llvm-exegesis/X86/SnippetFileTest.cpp

auto Error = TestCommon(R"(
     # LLVM-EXEGESIS-LIVEIN
     incq %rax
   )")
                    .takeError();
   EXPECT_TRUE((bool)Error);
   consumeError(std::move(Error));
 }
 
+TEST_F(X86SnippetFileTest, NoAsmStreamer) {
+  auto Snippets = TestCommon(R"(
+    .cv_fpo_proc foo 4
+  )");
+  EXPECT_FALSE((bool)Snippets.takeError());
+}
+
 } // namespace
 } // namespace exegesis
 } // namespace llvm