[NewPM][MSan] Add sanitizer at O0

[philip.pfaffe]

Summary

New-PM's msan currently is not inserted at O0, unlike with the legacy PM.

[fedor.sergeev]

Please, update the msan test that currently runs with -O1.

[leonardchan]

Will need to be rebased after rC353985. Should this also include tsan, unless this is just for msan specifically?

[chandlerc]

In D57793#1403303, @leonardchan wrote:

Will need to be rebased after rC353985. Should this also include tsan, unless this is just for msan specifically?

Yeah, I suspect so. If you want, maybe take this over? Would be great to get this landed.

[leonardchan]

In D57793#1403308, @chandlerc wrote:

In D57793#1403303, @leonardchan wrote:

Will need to be rebased after rC353985. Should this also include tsan, unless this is just for msan specifically?

Yeah, I suspect so. If you want, maybe take this over? Would be great to get this landed.

Made patch D58424 for this.

clang/lib/CodeGen/BackendUtil.cpp

case 2:
       return PassBuilder::Oz;
     }
 
   case 3:
     return PassBuilder::O3;
   }
 }
 
+FunctionPassManager addSanitizersAtO0() {
+  FunctionPassManager FPM;
+  if (LangOpts.Sanitize.has(SanitizerKind::Memory))
+    FPM.addPass(MemorySanitizerPass());
+
+  return FPM;
+}
+
 /// A clean version of `EmitAssembly` that uses the new pass manager.
 ///
 /// Not all features are currently supported in this system, but where
 /// necessary it falls back to the legacy pass manager to at least provide
 /// basic functionality.
 ///
 /// This API is planned to have its functionality finished and then to replace
 /// `EmitAssembly` at some point in the future when the default switches.
if (CodeGenOpts.OptimizationLevel == 0) {
       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
         PB.registerScalarOptimizerLateEPCallback(
             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
               FPM.addPass(BoundsCheckingPass());
             });
       if (LangOpts.Sanitize.has(SanitizerKind::Memory))
         PB.registerOptimizerLastEPCallback(
             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
-              FPM.addPass(MemorySanitizerPass({}));
+              FPM.addPass(MemorySanitizerPass());
             });
       if (LangOpts.Sanitize.has(SanitizerKind::Thread))
         PB.registerOptimizerLastEPCallback(
             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
               FPM.addPass(ThreadSanitizerPass());
             });
       if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts))
         PB.registerPipelineStartEPCallback([Options](ModulePassManager &MPM) {
if (CodeGenOpts.OptimizationLevel == 0) {
                                                 CodeGenOpts.DebugPassManager);
         MPM.addPass(CanonicalizeAliasesPass());
         MPM.addPass(NameAnonGlobalPass());
       } else {
         MPM = PB.buildPerModuleDefaultPipeline(Level,
                                                CodeGenOpts.DebugPassManager);
       }
     }
+    if (Level == PassBuilder::O0)
+      MPM.addPass(addSanitizersAtO0());
   }
 
   // FIXME: We still use the legacy pass manager to do code generation. We
   // create that pass manager here and use it as needed below.
   legacy::PassManager CodeGenPasses;
   bool NeedCodeGen = false;
   std::unique_ptr<llvm::ToolOutputFile> ThinLinkOS, DwoOS;