NewPM: Add an extension point for the start of the pipeline.

This applies to most pipelines except the LTO and ThinLTO backend
actions - it is for use at the beginning of the overall pipeline.

This extension point will be used to add the GCOV pass when enabled in
Clang.

llvm-svn: 323166

5 files changed, 47 insertions, 4 deletions

diff --git a/llvm/include/llvm/Passes/PassBuilder.h b/llvm/include/llvm/Passes/PassBuilder.h
index b6998882625..5efcda0a1b4 100644
--- a/llvm/include/llvm/Passes/PassBuilder.h
+++ b/llvm/include/llvm/Passes/PassBuilder.h
@@ -19,6 +19,7 @@
 #include "llvm/ADT/Optional.h"
 #include "llvm/Analysis/CGSCCPassManager.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/Transforms/Instrumentation.h"
 #include "llvm/Transforms/Scalar/LoopPassManager.h"
 #include <vector>
 
@@ -476,6 +477,16 @@ public:
     VectorizerStartEPCallbacks.push_back(C);
   }
 
+  /// Register a callback for a default optimizer pipeline extension point.
+  ///
+  /// This extension point allows adding optimization once at the start of the
+  /// pipeline. This does not apply to 'backend' compiles (LTO and ThinLTO
+  /// link-time pipelines).
+  void registerPipelineStartEPCallback(
+      const std::function<void(ModulePassManager &)> &C) {
+    PipelineStartEPCallbacks.push_back(C);
+  }
+
   /// \brief Register a callback for parsing an AliasAnalysis Name to populate
   /// the given AAManager \p AA
   void registerParseAACallback(
@@ -589,6 +600,8 @@ private:
   SmallVector<std::function<void(FunctionPassManager &, OptimizationLevel)>, 2>
       VectorizerStartEPCallbacks;
   // Module callbacks
+  SmallVector<std::function<void(ModulePassManager &)>, 2>
+      PipelineStartEPCallbacks;
   SmallVector<std::function<void(ModuleAnalysisManager &)>, 2>
       ModuleAnalysisRegistrationCallbacks;
   SmallVector<std::function<bool(StringRef, ModulePassManager &,
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index c344a3165a0..07c6f55afd6 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -150,7 +150,6 @@
 #include "llvm/Transforms/Vectorize/LoopVectorize.h"
 #include "llvm/Transforms/Vectorize/SLPVectorizer.h"
 
-
 using namespace llvm;
 
 static cl::opt<unsigned> MaxDevirtIterations("pm-max-devirt-iterations",
@@ -841,6 +840,10 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
+  // Apply module pipeline start EP callback.
+  for (auto &C : PipelineStartEPCallbacks)
+    C(MPM);
+
   if (PGOOpt && PGOOpt->SamplePGOSupport)
     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
 
@@ -867,6 +870,10 @@ PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level,
   if (PGOOpt && PGOOpt->SamplePGOSupport)
     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
 
+  // Apply module pipeline start EP callback.
+  for (auto &C : PipelineStartEPCallbacks)
+    C(MPM);
+
   // 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
   // can.
diff --git a/llvm/test/Other/new-pm-defaults.ll b/llvm/test/Other/new-pm-defaults.ll
index 96b925f9d69..2be8fdeb06f 100644
--- a/llvm/test/Other/new-pm-defaults.ll
+++ b/llvm/test/Other/new-pm-defaults.ll
@@ -56,11 +56,22 @@
 ; RUN:     -passes='default<O3>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
 ; RUN:     --check-prefix=CHECK-EP-VECTORIZER-START
+; RUN: opt -disable-verify -debug-pass-manager \
+; RUN:     -passes-ep-pipeline-start='no-op-module' \
+; RUN:     -passes='default<O3>' -S  %s 2>&1 \
+; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
+; RUN:     --check-prefix=CHECK-EP-PIPELINE-START
+; RUN: opt -disable-verify -debug-pass-manager \
+; RUN:     -passes-ep-pipeline-start='no-op-module' \
+; RUN:     -passes='lto-pre-link<O3>' -S  %s 2>&1 \
+; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
+; RUN:     --check-prefix=CHECK-EP-PIPELINE-START
 
 ; CHECK-O: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
+; CHECK-EP-PIPELINE-START-NEXT: Running pass: NoOpModulePass
 ; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
diff --git a/llvm/test/Other/new-pm-thinlto-defaults.ll b/llvm/test/Other/new-pm-thinlto-defaults.ll
index 077d48bb6ae..c40e46aee6e 100644
--- a/llvm/test/Other/new-pm-thinlto-defaults.ll
+++ b/llvm/test/Other/new-pm-thinlto-defaults.ll
@@ -15,8 +15,8 @@
 ; RUN:     -passes='thinlto-pre-link<O2>,name-anon-globals' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O2,CHECK-PRELINK-O,CHECK-PRELINK-O-NODIS,CHECK-PRELINK-O2
 ; RUN: opt -disable-verify -debug-pass-manager \
-; RUN:     -passes='thinlto-pre-link<O3>,name-anon-globals' -S  %s 2>&1 \
-; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O3,CHECK-PRELINK-O,CHECK-PRELINK-O-NODIS,CHECK-PRELINK-O3
+; RUN:     -passes='thinlto-pre-link<O3>,name-anon-globals' -S -passes-ep-pipeline-start='no-op-module' %s 2>&1 \
+; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O3,CHECK-PRELINK-O,CHECK-PRELINK-O-NODIS,CHECK-PRELINK-O3,CHECK-EP-PIPELINE-START
 ; RUN: opt -disable-verify -debug-pass-manager \
 ; RUN:     -passes='thinlto-pre-link<Os>,name-anon-globals' -S %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-Os,CHECK-PRELINK-O,CHECK-PRELINK-O-NODIS,CHECK-PRELINK-Os
@@ -34,7 +34,7 @@
 ; RUN: opt -disable-verify -debug-pass-manager \
 ; RUN:     -passes='thinlto<O2>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O2,CHECK-POSTLINK-O,CHECK-POSTLINK-O2
-; RUN: opt -disable-verify -debug-pass-manager \
+; RUN: opt -disable-verify -debug-pass-manager -passes-ep-pipeline-start='no-op-module' \
 ; RUN:     -passes='thinlto<O3>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O3,CHECK-POSTLINK-O,CHECK-POSTLINK-O3
 ; RUN: opt -disable-verify -debug-pass-manager \
@@ -51,6 +51,7 @@
 ; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
+; CHECK-EP-PIPELINE-START-NEXT: Running pass: NoOpModulePass
 ; CHECK-DIS-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}AddDiscriminatorsPass{{.*}}>
 ; CHECK-DIS-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-POSTLINK-O-NEXT: Running pass: PGOIndirectCallPromotion
diff --git a/llvm/tools/opt/NewPMDriver.cpp b/llvm/tools/opt/NewPMDriver.cpp
index a3f16f2538c..bf512e0db84 100644
--- a/llvm/tools/opt/NewPMDriver.cpp
+++ b/llvm/tools/opt/NewPMDriver.cpp
@@ -82,6 +82,11 @@ static cl::opt<std::string> VectorizerStartEPPipeline(
     cl::desc("A textual description of the function pass pipeline inserted at "
              "the VectorizerStart extension point into default pipelines"),
     cl::Hidden);
+static cl::opt<std::string> PipelineStartEPPipeline(
+    "passes-ep-pipeline-start",
+    cl::desc("A textual description of the function pass pipeline inserted at "
+             "the PipelineStart extension point into default pipelines"),
+    cl::Hidden);
 enum PGOKind { NoPGO, InstrGen, InstrUse, SampleUse };
 static cl::opt<PGOKind> PGOKindFlag(
     "pgo-kind", cl::init(NoPGO), cl::Hidden,
@@ -159,6 +164,12 @@ static void registerEPCallbacks(PassBuilder &PB, bool VerifyEachPass,
       PB.parsePassPipeline(PM, VectorizerStartEPPipeline, VerifyEachPass,
                            DebugLogging);
     });
+  if (tryParsePipelineText<ModulePassManager>(PB, PipelineStartEPPipeline))
+    PB.registerPipelineStartEPCallback(
+        [&PB, VerifyEachPass, DebugLogging](ModulePassManager &PM) {
+          PB.parsePassPipeline(PM, PipelineStartEPPipeline, VerifyEachPass,
+                               DebugLogging);
+        });
 }
 
 #ifdef LINK_POLLY_INTO_TOOLS