[PATCH] D102709: [MCA] llvm-mca MCTargetStreamer segfault fix

[Andrea Di Biagio via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGe5d59db46938: [MCA] llvm-mca MCTargetStreamer segfault fix (authored by holland11, committed by andreadb).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102709/new/

https://reviews.llvm.org/D102709

Files:
  llvm/test/tools/llvm-mca/X86/cv_fpo_directive_no_segfault.s
  llvm/tools/llvm-mca/CodeRegionGenerator.cpp
  llvm/tools/llvm-mca/CodeRegionGenerator.h
  llvm/tools/llvm-mca/llvm-mca.cpp


Index: llvm/tools/llvm-mca/llvm-mca.cpp
===================================================================
--- llvm/tools/llvm-mca/llvm-mca.cpp
+++ llvm/tools/llvm-mca/llvm-mca.cpp
@@ -389,9 +389,28 @@
   std::unique_ptr<MCInstrAnalysis> MCIA(
       TheTarget->createMCInstrAnalysis(MCII.get()));
 
+  // Need to initialize an MCInstPrinter as it is
+  // required for initializing the MCTargetStreamer
+  // which needs to happen within the CRG.parseCodeRegions() call below.
+  // Without an MCTargetStreamer, certain assembly directives can trigger a
+  // segfault. (For example, the .cv_fpo_proc directive on x86 will segfault if
+  // we don't initialize the MCTargetStreamer.)
+  unsigned IPtempOutputAsmVariant =
+      OutputAsmVariant == -1 ? 0 : OutputAsmVariant;
+  std::unique_ptr<MCInstPrinter> IPtemp(TheTarget->createMCInstPrinter(
+      Triple(TripleName), IPtempOutputAsmVariant, *MAI, *MCII, *MRI));
+  if (!IPtemp) {
+    WithColor::error()
+        << "unable to create instruction printer for target triple '"
+        << TheTriple.normalize() << "' with assembly variant "
+        << IPtempOutputAsmVariant << ".\n";
+    return 1;
+  }
+
   // Parse the input and create CodeRegions that llvm-mca can analyze.
   mca::AsmCodeRegionGenerator CRG(*TheTarget, SrcMgr, Ctx, *MAI, *STI, *MCII);
-  Expected<const mca::CodeRegions &> RegionsOrErr = CRG.parseCodeRegions();
+  Expected<const mca::CodeRegions &> RegionsOrErr =
+      CRG.parseCodeRegions(std::move(IPtemp));
   if (!RegionsOrErr) {
     if (auto Err =
             handleErrors(RegionsOrErr.takeError(), [](const StringError &E) {
Index: llvm/tools/llvm-mca/CodeRegionGenerator.h
===================================================================
--- llvm/tools/llvm-mca/CodeRegionGenerator.h
+++ llvm/tools/llvm-mca/CodeRegionGenerator.h
@@ -39,7 +39,8 @@
 public:
   CodeRegionGenerator(SourceMgr &SM) : Regions(SM) {}
   virtual ~CodeRegionGenerator();
-  virtual Expected<const CodeRegions &> parseCodeRegions() = 0;
+  virtual Expected<const CodeRegions &>
+  parseCodeRegions(const std::unique_ptr<MCInstPrinter> &IP) = 0;
 };
 
 /// This class is responsible for parsing input ASM and generating
@@ -60,7 +61,8 @@
         AssemblerDialect(0) {}
 
   unsigned getAssemblerDialect() const { return AssemblerDialect; }
-  Expected<const CodeRegions &> parseCodeRegions() override;
+  Expected<const CodeRegions &>
+  parseCodeRegions(const std::unique_ptr<MCInstPrinter> &IP) override;
 };
 
 } // namespace mca
Index: llvm/tools/llvm-mca/CodeRegionGenerator.cpp
===================================================================
--- llvm/tools/llvm-mca/CodeRegionGenerator.cpp
+++ llvm/tools/llvm-mca/CodeRegionGenerator.cpp
@@ -106,11 +106,21 @@
   Regions.beginRegion(Comment, Loc);
 }
 
-Expected<const CodeRegions &> AsmCodeRegionGenerator::parseCodeRegions() {
+Expected<const CodeRegions &> AsmCodeRegionGenerator::parseCodeRegions(
+    const std::unique_ptr<MCInstPrinter> &IP) {
   MCTargetOptions Opts;
   Opts.PreserveAsmComments = false;
   MCStreamerWrapper Str(Ctx, Regions);
 
+  // Need to initialize an MCTargetStreamer otherwise
+  // certain asm directives will cause a segfault.
+  // Using nulls() so that anything emitted by the MCTagetStreamer
+  // doesn't show up in the llvm-mca output.
+  raw_ostream &OSRef = nulls();
+  formatted_raw_ostream FOSRef(OSRef);
+  TheTarget.createAsmTargetStreamer(Str, FOSRef, IP.get(),
+                                    /*IsVerboseAsm=*/true);
+
   // Create a MCAsmParser and setup the lexer to recognize llvm-mca ASM
   // comments.
   std::unique_ptr<MCAsmParser> Parser(
Index: llvm/test/tools/llvm-mca/X86/cv_fpo_directive_no_segfault.s
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-mca/X86/cv_fpo_directive_no_segfault.s
@@ -0,0 +1,9 @@
+# RUN: llvm-mca -mtriple=x86_64-unknown-unknown -resource-pressure=false -instruction-info=false < %s | FileCheck %s
+
+.cv_fpo_pushreg ebx
+add %eax, %eax
+add %ebx, %ebx
+add %ecx, %ecx
+add %edx, %edx
+
+# CHECK:      Iterations:        100


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