Move the SampleProfileLoader right after EarlyFPM.

Summary: SampleProfileLoader pass do need to happen after some early cleanup passes so that inlining can happen correctly inside the SampleProfileLoader pass.

Reviewers: chandlerc, davidxl, tejohnson

Reviewed By: chandlerc, tejohnson

Subscribers: sanjoy, mehdi_amini, eraman, llvm-commits

Differential Revision: https://reviews.llvm.org/D36333

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310296 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Passes/PassBuilder.cpp

@@ -540,8 +540,32 @@ PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
   EarlyFPM.addPass(SROA());
   EarlyFPM.addPass(EarlyCSEPass());
   EarlyFPM.addPass(LowerExpectIntrinsicPass());
+  // In SamplePGO ThinLTO backend, we need instcombine before profile annotation
+  // to convert bitcast to direct calls so that they can be inlined during the
+  // profile annotation prepration step.
+  // More details about SamplePGO design can be found in:
+  // https://research.google.com/pubs/pub45290.html
+  // FIXME: revisit how SampleProfileLoad/Inliner/ICP is structured.
+  if (PGOOpt && !PGOOpt->SampleProfileFile.empty() &&
+      Phase == ThinLTOPhase::PostLink)
+    EarlyFPM.addPass(InstCombinePass());
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(EarlyFPM)));
 
+  if (PGOOpt && !PGOOpt->SampleProfileFile.empty()) {
+    // Annotate sample profile right after early FPM to ensure freshness of
+    // the debug info.
+    MPM.addPass(SampleProfileLoaderPass(PGOOpt->SampleProfileFile));
+    // Do not invoke ICP in the ThinLTOPrelink phase as it makes it hard
+    // for the profile annotation to be accurate in the ThinLTO backend.
+    if (Phase != ThinLTOPhase::PreLink)
+      // We perform early indirect call promotion here, before globalopt.
+      // This is important for the ThinLTO backend phase because otherwise
+      // imported available_externally functions look unreferenced and are
+      // removed.
+      MPM.addPass(PGOIndirectCallPromotion(Phase == ThinLTOPhase::PostLink,
+                                           true));
+  }
+
   // Interprocedural constant propagation now that basic cleanup has occured
   // and prior to optimizing globals.
   // FIXME: This position in the pipeline hasn't been carefully considered in
@@ -768,13 +792,8 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
-  if (PGOOpt && PGOOpt->SamplePGOSupport) {
+  if (PGOOpt && PGOOpt->SamplePGOSupport)
     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
-    if (!PGOOpt->SampleProfileFile.empty()) {
-      MPM.addPass(SampleProfileLoaderPass(PGOOpt->SampleProfileFile));
-      MPM.addPass(PGOIndirectCallPromotion(false, true));
-    }
-  }
 
   // Add the core simplification pipeline.
   MPM.addPass(buildModuleSimplificationPipeline(Level, ThinLTOPhase::None,
@@ -796,14 +815,8 @@ PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level,
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
-  // Invoke the SamplePGO annotation pass for the first time to annotate
+  if (PGOOpt && PGOOpt->SamplePGOSupport)
-  // profile for functions in the current module to give ThinLink info
-  // about module grouping.
-  if (PGOOpt && PGOOpt->SamplePGOSupport) {
     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
-    if (!PGOOpt->SampleProfileFile.empty())
-      MPM.addPass(SampleProfileLoaderPass(PGOOpt->SampleProfileFile));
-  }
 
   // If we are planning to perform ThinLTO later, we don't bloat the code with
   // unrolling/vectorization/... now. Just simplify the module as much as we
@@ -839,16 +852,14 @@ PassBuilder::buildThinLTODefaultPipeline(OptimizationLevel Level,
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
-  // Invoke the SamplePGO annotation pass for the second time to annotate on
-  // functions imported from other modules.
-  if (PGOOpt && !PGOOpt->SampleProfileFile.empty())
-    MPM.addPass(SampleProfileLoaderPass(PGOOpt->SampleProfileFile));
-
   // During the ThinLTO backend phase we perform early indirect call promotion
   // here, before globalopt. Otherwise imported available_externally functions
   // look unreferenced and are removed.
-  MPM.addPass(PGOIndirectCallPromotion(
+  // FIXME: move this into buildModuleSimplificationPipeline to merge the logic
-      true /* InLTO */, PGOOpt && !PGOOpt->SampleProfileFile.empty()));
+  //        with SamplePGO.
+  if (PGOOpt && !PGOOpt->ProfileUseFile.empty())
+    MPM.addPass(PGOIndirectCallPromotion(true /* InLTO */,
+                                         false /* SamplePGO */));
 
   // Add the core simplification pipeline.
   MPM.addPass(buildModuleSimplificationPipeline(Level, ThinLTOPhase::PostLink,

test/Other/new-pm-pgo.ll

@@ -1,13 +1,27 @@
 ; RUN: opt -debug-pass-manager -passes='default<O2>' -pgo-kind=new-pm-pgo-instr-gen-pipeline -profile-file='temp' %s 2>&1 |FileCheck %s --check-prefixes=GEN
 ; RUN: llvm-profdata merge %S/Inputs/new-pm-pgo.proftext -o %t.profdata
 ; RUN: opt -debug-pass-manager -passes='default<O2>' -pgo-kind=new-pm-pgo-instr-use-pipeline -profile-file='%t.profdata' %s 2>&1 |FileCheck %s --check-prefixes=USE
-; RUN: opt -debug-pass-manager -passes='default<O2>' -pgo-kind=new-pm-pgo-sample-use-pipeline -profile-file='%S/Inputs/new-pm-pgo.prof' %s 2>&1 |FileCheck %s --check-prefixes=SAMPLE_USE
+; RUN: opt -debug-pass-manager -passes='default<O2>' -pgo-kind=new-pm-pgo-sample-use-pipeline -profile-file='%S/Inputs/new-pm-pgo.prof' %s 2>&1 \
+; RUN:     |FileCheck %s --check-prefixes=SAMPLE_USE,SAMPLE_USE_O
+; RUN: opt -debug-pass-manager -passes='thinlto-pre-link<O2>' -pgo-kind=new-pm-pgo-sample-use-pipeline -profile-file='%S/Inputs/new-pm-pgo.prof' %s 2>&1 \
+; RUN:     |FileCheck %s --check-prefixes=SAMPLE_USE,SAMPLE_USE_PRE_LINK
+; RUN: opt -debug-pass-manager -passes='thinlto<O2>' -pgo-kind=new-pm-pgo-sample-use-pipeline -profile-file='%S/Inputs/new-pm-pgo.prof' %s 2>&1 \
+; RUN:     |FileCheck %s --check-prefixes=SAMPLE_USE,SAMPLE_USE_POST_LINK
 ; RUN: opt -debug-pass-manager -passes='default<O2>' -new-pm-debug-info-for-profiling %s 2>&1 |FileCheck %s --check-prefixes=SAMPLE_GEN
 ;
 ; GEN: Running pass: PGOInstrumentationGen
 ; USE: Running pass: PGOInstrumentationUse
-; SAMPLE_USE: Running pass: ModuleToFunctionPassAdaptor<{{.*}}AddDiscriminatorsPass{{.*}}>
+; SAMPLE_USE_O: Running pass: ModuleToFunctionPassAdaptor<{{.*}}AddDiscriminatorsPass{{.*}}>
+; SAMPLE_USE_PRE_LINK: Running pass: ModuleToFunctionPassAdaptor<{{.*}}AddDiscriminatorsPass{{.*}}>
+; SAMPLE_USE: Running pass: SimplifyCFGPass
+; SAMPLE_USE: Running pass: SROA
+; SAMPLE_USE: Running pass: EarlyCSEPass
+; SAMPLE_USE: Running pass: LowerExpectIntrinsicPass
+; SAMPLE_USE_POST_LINK: Running pass: InstCombinePass
 ; SAMPLE_USE: Running pass: SampleProfileLoaderPass
+; SAMPLE_USE_O: Running pass: PGOIndirectCallPromotion
+; SAMPLE_USE_POST_LINK-NOT: Running pass: GlobalOptPass
+; SAMPLE_USE_POST_LINK: Running pass: PGOIndirectCallPromotion
 ; SAMPLE_GEN: Running pass: ModuleToFunctionPassAdaptor<{{.*}}AddDiscriminatorsPass{{.*}}>
 
 define void @foo() {

test/Other/new-pm-thinlto-defaults.ll

@@ -53,15 +53,13 @@
 ; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
 ; CHECK-DIS-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}AddDiscriminatorsPass{{.*}}>
 ; CHECK-DIS-NEXT: Running analysis: InnerAnalysisManagerProxy
-; CHECK-POSTLINK-O-NEXT: Running pass: PGOIndirectCallPromotion
-; CHECK-POSTLINK-O-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}Function
-; CHECK-POSTLINK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
 ; CHECK-PRELINK-O-NODIS-NEXT: Running analysis: InnerAnalysisManagerProxy
+; CHECK-POSTLINK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-O-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
@@ -80,6 +78,7 @@
 ; CHECK-O-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-PRELINK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
+; CHECK-POSTLINK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}GlobalsAA