[LLVM][PassBuilder] Extend the function signature of callback for optimizer pipeline extension point

These callbacks can be invoked in multiple places when building an optimization
pipeline, both in compile time and link time. However, there is no indicator on
what pipeline it is currently building.

In this patch, an extra argument is added to indicate its (Thin)LTO stage such
that the callback can check it if needed. There is no test expected from this,
and the benefit of this change will be demonstrated in #66488.

Author: shiltian

clang/lib/CodeGen/BackendUtil.cpp

@@ -643,7 +643,7 @@ static void addKCFIPass(const Triple &TargetTriple, const LangOptions &LangOpts,
 
   // Ensure we lower KCFI operand bundles with -O0.
   PB.registerOptimizerLastEPCallback(
-      [&](ModulePassManager &MPM, OptimizationLevel Level) {
+      [&](ModulePassManager &MPM, OptimizationLevel Level, ThinOrFullLTOPhase) {
         if (Level == OptimizationLevel::O0 &&
             LangOpts.Sanitize.has(SanitizerKind::KCFI))
           MPM.addPass(createModuleToFunctionPassAdaptor(KCFIPass()));
@@ -662,8 +662,8 @@ static void addKCFIPass(const Triple &TargetTriple, const LangOptions &LangOpts,
 static void addSanitizers(const Triple &TargetTriple,
                           const CodeGenOptions &CodeGenOpts,
                           const LangOptions &LangOpts, PassBuilder &PB) {
-  auto SanitizersCallback = [&](ModulePassManager &MPM,
-                                OptimizationLevel Level) {
+  auto SanitizersCallback = [&](ModulePassManager &MPM, OptimizationLevel Level,
+                                ThinOrFullLTOPhase) {
     if (CodeGenOpts.hasSanitizeCoverage()) {
       auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
       MPM.addPass(SanitizerCoveragePass(
@@ -749,7 +749,7 @@ static void addSanitizers(const Triple &TargetTriple,
     PB.registerOptimizerEarlyEPCallback(
         [SanitizersCallback](ModulePassManager &MPM, OptimizationLevel Level) {
           ModulePassManager NewMPM;
-          SanitizersCallback(NewMPM, Level);
+          SanitizersCallback(NewMPM, Level, ThinOrFullLTOPhase::None);
           if (!NewMPM.isEmpty()) {
             // Sanitizers can abandon<GlobalsAA>.
             NewMPM.addPass(RequireAnalysisPass<GlobalsAA, llvm::Module>());
@@ -1018,11 +1018,12 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
     // TODO: Consider passing the MemoryProfileOutput to the pass builder via
     // the PGOOptions, and set this up there.
     if (!CodeGenOpts.MemoryProfileOutput.empty()) {
-      PB.registerOptimizerLastEPCallback(
-          [](ModulePassManager &MPM, OptimizationLevel Level) {
-            MPM.addPass(createModuleToFunctionPassAdaptor(MemProfilerPass()));
-            MPM.addPass(ModuleMemProfilerPass());
-          });
+      PB.registerOptimizerLastEPCallback([](ModulePassManager &MPM,
+                                            OptimizationLevel Level,
+                                            ThinOrFullLTOPhase) {
+        MPM.addPass(createModuleToFunctionPassAdaptor(MemProfilerPass()));
+        MPM.addPass(ModuleMemProfilerPass());
+      });
     }
 
     if (CodeGenOpts.FatLTO) {

llvm/include/llvm/Passes/PassBuilder.h

@@ -497,7 +497,8 @@ class PassBuilder {
   /// This extension point allows adding optimizations at the very end of the
   /// function optimization pipeline.
   void registerOptimizerLastEPCallback(
-      const std::function<void(ModulePassManager &, OptimizationLevel)> &C) {
+      const std::function<void(ModulePassManager &, OptimizationLevel,
+                               ThinOrFullLTOPhase)> &C) {
     OptimizerLastEPCallbacks.push_back(C);
   }
 
@@ -630,7 +631,8 @@ class PassBuilder {
   void invokeOptimizerEarlyEPCallbacks(ModulePassManager &MPM,
                                        OptimizationLevel Level);
   void invokeOptimizerLastEPCallbacks(ModulePassManager &MPM,
-                                      OptimizationLevel Level);
+                                      OptimizationLevel Level,
+                                      ThinOrFullLTOPhase Phase);
   void invokeFullLinkTimeOptimizationEarlyEPCallbacks(ModulePassManager &MPM,
                                                       OptimizationLevel Level);
   void invokeFullLinkTimeOptimizationLastEPCallbacks(ModulePassManager &MPM,
@@ -755,7 +757,9 @@ class PassBuilder {
   // Module callbacks
   SmallVector<std::function<void(ModulePassManager &, OptimizationLevel)>, 2>
       OptimizerEarlyEPCallbacks;
-  SmallVector<std::function<void(ModulePassManager &, OptimizationLevel)>, 2>
+  SmallVector<std::function<void(ModulePassManager &, OptimizationLevel,
+                                 ThinOrFullLTOPhase)>,
+              2>
       OptimizerLastEPCallbacks;
   SmallVector<std::function<void(ModulePassManager &, OptimizationLevel)>, 2>
       FullLinkTimeOptimizationEarlyEPCallbacks;

llvm/lib/Passes/PassBuilderPipelines.cpp

@@ -365,9 +365,10 @@ void PassBuilder::invokeOptimizerEarlyEPCallbacks(ModulePassManager &MPM,
     C(MPM, Level);
 }
 void PassBuilder::invokeOptimizerLastEPCallbacks(ModulePassManager &MPM,
-                                                 OptimizationLevel Level) {
+                                                 OptimizationLevel Level,
+                                                 ThinOrFullLTOPhase Phase) {
   for (auto &C : OptimizerLastEPCallbacks)
-    C(MPM, Level);
+    C(MPM, Level, Phase);
 }
 void PassBuilder::invokeFullLinkTimeOptimizationEarlyEPCallbacks(
     ModulePassManager &MPM, OptimizationLevel Level) {
@@ -1524,7 +1525,7 @@ PassBuilder::buildModuleOptimizationPipeline(OptimizationLevel Level,
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(OptimizePM),
                                                 PTO.EagerlyInvalidateAnalyses));
 
-  invokeOptimizerLastEPCallbacks(MPM, Level);
+  invokeOptimizerLastEPCallbacks(MPM, Level, LTOPhase);
 
   // Split out cold code. Splitting is done late to avoid hiding context from
   // other optimizations and inadvertently regressing performance. The tradeoff
@@ -1671,7 +1672,8 @@ PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level) {
   // optimization is going to be done in PostLink stage, but clang can't add
   // callbacks there in case of in-process ThinLTO called by linker.
   invokeOptimizerEarlyEPCallbacks(MPM, Level);
-  invokeOptimizerLastEPCallbacks(MPM, Level);
+  invokeOptimizerLastEPCallbacks(MPM, Level,
+                                 ThinOrFullLTOPhase::ThinLTOPreLink);
 
   // Emit annotation remarks.
   addAnnotationRemarksPass(MPM);
@@ -2159,7 +2161,9 @@ ModulePassManager PassBuilder::buildO0DefaultPipeline(OptimizationLevel Level,
   CoroPM.addPass(GlobalDCEPass());
   MPM.addPass(CoroConditionalWrapper(std::move(CoroPM)));
 
-  invokeOptimizerLastEPCallbacks(MPM, Level);
+  invokeOptimizerLastEPCallbacks(MPM, Level,
+                                 LTOPreLink ? ThinOrFullLTOPhase::ThinLTOPreLink
+                                            : ThinOrFullLTOPhase::None);
 
   if (LTOPreLink)
     addRequiredLTOPreLinkPasses(MPM);

llvm/lib/Target/AMDGPU/AMDGPU.h

@@ -287,8 +287,13 @@ class AMDGPUAttributorPass : public PassInfoMixin<AMDGPUAttributorPass> {
 private:
   TargetMachine &TM;
 
+  /// Asserts whether we can assume whole program visibility.
+  bool HasWholeProgramVisibility = false;
+
 public:
-  AMDGPUAttributorPass(TargetMachine &TM) : TM(TM){};
+  AMDGPUAttributorPass(TargetMachine &TM,
+                       bool HasWholeProgramVisibility = false)
+      : TM(TM), HasWholeProgramVisibility(HasWholeProgramVisibility) {};
   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
 };
 

llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp

@@ -1023,7 +1023,8 @@ static void addPreloadKernArgHint(Function &F, TargetMachine &TM) {
   }
 }
 
-static bool runImpl(Module &M, AnalysisGetter &AG, TargetMachine &TM) {
+static bool runImpl(Module &M, AnalysisGetter &AG, TargetMachine &TM,
+                    bool HasWholeProgramVisibility) {
   SetVector<Function *> Functions;
   for (Function &F : M) {
     if (!F.isIntrinsic())
@@ -1041,6 +1042,7 @@ static bool runImpl(Module &M, AnalysisGetter &AG, TargetMachine &TM) {
        &AAUnderlyingObjects::ID, &AAIndirectCallInfo::ID});
 
   AttributorConfig AC(CGUpdater);
+  AC.IsClosedWorldModule = HasWholeProgramVisibility;
   AC.Allowed = &Allowed;
   AC.IsModulePass = true;
   AC.DefaultInitializeLiveInternals = false;
@@ -1086,7 +1088,7 @@ class AMDGPUAttributorLegacy : public ModulePass {
 
   bool runOnModule(Module &M) override {
     AnalysisGetter AG(this);
-    return runImpl(M, AG, *TM);
+    return runImpl(M, AG, *TM, /*HasWholeProgramVisibility=*/false);
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
@@ -1107,8 +1109,9 @@ PreservedAnalyses llvm::AMDGPUAttributorPass::run(Module &M,
   AnalysisGetter AG(FAM);
 
   // TODO: Probably preserves CFG
-  return runImpl(M, AG, TM) ? PreservedAnalyses::none()
-                            : PreservedAnalyses::all();
+  return runImpl(M, AG, TM, HasWholeProgramVisibility)
+             ? PreservedAnalyses::none()
+             : PreservedAnalyses::all();
 }
 
 char AMDGPUAttributorLegacy::ID = 0;

llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp

@@ -735,12 +735,15 @@ void AMDGPUTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
       });
 
   // FIXME: Why is AMDGPUAttributor not in CGSCC?
-  PB.registerOptimizerLastEPCallback(
-      [this](ModulePassManager &MPM, OptimizationLevel Level) {
-        if (Level != OptimizationLevel::O0) {
-          MPM.addPass(AMDGPUAttributorPass(*this));
-        }
-      });
+  PB.registerOptimizerLastEPCallback([this](ModulePassManager &MPM,
+                                            OptimizationLevel Level,
+                                            ThinOrFullLTOPhase Phase) {
+    if (Level != OptimizationLevel::O0) {
+      MPM.addPass(AMDGPUAttributorPass(
+          *this, Phase == ThinOrFullLTOPhase::FullLTOPostLink ||
+                     Phase == ThinOrFullLTOPhase::ThinLTOPostLink));
+    }
+  });
 
   PB.registerFullLinkTimeOptimizationLastEPCallback(
       [this](ModulePassManager &PM, OptimizationLevel Level) {

llvm/tools/opt/NewPMDriver.cpp

@@ -310,7 +310,7 @@ static void registerEPCallbacks(PassBuilder &PB) {
         });
   if (tryParsePipelineText<ModulePassManager>(PB, OptimizerLastEPPipeline))
     PB.registerOptimizerLastEPCallback(
-        [&PB](ModulePassManager &PM, OptimizationLevel) {
+        [&PB](ModulePassManager &PM, OptimizationLevel, ThinOrFullLTOPhase) {
           ExitOnError Err("Unable to parse OptimizerLastEP pipeline: ");
           Err(PB.parsePassPipeline(PM, OptimizerLastEPPipeline));
         });