[NewPM] Add CrossDSOCFI pass irrespective of LTO optimization level

[pirama]

Summary

This pass is not an optimization and is needed for CFI functionality
(cross-dso verification).

[pirama]

s/CHECK-LTO/CHECK-LTO-NEXT in new-pm-O0-defaults.ll

[aeubanks]

thanks!

llvm/lib/Passes/PassBuilder.cpp

1654–1655

this comment seems unnecessary, many passes are required

[pirama]

Remove note in comment.

llvm/lib/Passes/PassBuilder.cpp

 ModulePassManager
 PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
                                      ModuleSummaryIndex *ExportSummary) {
   ModulePassManager MPM;
 
   // Convert @llvm.global.annotations to !annotation metadata.
   MPM.addPass(Annotation2MetadataPass());
 
+  // Create a function that performs CFI checks for cross-DSO calls with targets
+  // in the current module.  (Note: Add this passs irrespective of the
+  // optimization level).
+  MPM.addPass(CrossDSOCFIPass());
+
   if (Level == OptimizationLevel::O0) {
     // The WPD and LowerTypeTest passes need to run at -O0 to lower type
     // metadata and intrinsics.
     MPM.addPass(WholeProgramDevirtPass(ExportSummary, nullptr));
     MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
     // Run a second time to clean up any type tests left behind by WPD for use
     // in ICP.
     MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));
PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
   MainFPM.addPass(LoopDistributePass());
 
   addVectorPasses(Level, MainFPM, /* IsLTO */ true);
 
   invokePeepholeEPCallbacks(MainFPM, Level);
   MainFPM.addPass(JumpThreadingPass(/*InsertFreezeWhenUnfoldingSelect*/ true));
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(MainFPM)));
 
-  // Create a function that performs CFI checks for cross-DSO calls with
-  // targets in the current module.
-  MPM.addPass(CrossDSOCFIPass());
-
   // Lower type metadata and the type.test intrinsic. This pass supports
   // clang's control flow integrity mechanisms (-fsanitize=cfi*) and needs
   // to be run at link time if CFI is enabled. This pass does nothing if
   // CFI is disabled.
   MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
   // Run a second time to clean up any type tests left behind by WPD for use
   // in ICP (which is performed earlier than this in the regular LTO pipeline).
   MPM.addPass(LowerTypeTestsPass(nullptr, nullptr, true));

llvm/test/Other/new-pm-O0-defaults.ll

 ; CHECK-MATRIX-NEXT: Running analysis: TargetIRAnalysis
 ; CHECK-PRE-LINK: Running pass: CanonicalizeAliasesPass
 ; CHECK-PRE-LINK-NEXT: Running pass: NameAnonGlobalPass
 ; CHECK-THINLTO: Running pass: Annotation2MetadataPass
 ; CHECK-THINLTO-NEXT: Running pass: LowerTypeTestsPass
 ; CHECK-THINLTO-NEXT: Running pass: EliminateAvailableExternallyPass
 ; CHECK-THINLTO-NEXT: Running pass: GlobalDCEPass
 ; CHECK-LTO: Running pass: Annotation2MetadataPass
+; CHECK-LTO: Running pass: CrossDSOCFIPass on [module]
 ; CHECK-LTO-NEXT: Running pass: WholeProgramDevirtPass
 ; CHECK-LTO-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-LTO-NEXT: Running pass: LowerTypeTestsPass
 ; CHECK-LTO-NEXT: Running pass: LowerTypeTestsPass
 ; CHECK-LTO-NEXT: Running pass: AnnotationRemarksPass
 ; CHECK-LTO-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-NEXT: Running pass: PrintModulePass
 

llvm/test/Other/new-pm-lto-defaults.ll

 ; RUN:     -passes='lto<Oz>' -S %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O23SZ
 ; RUN: opt -disable-verify -verify-cfg-preserved=0 -debug-pass-manager \
 ; RUN:     -passes='lto<O3>' -S  %s -passes-ep-peephole='no-op-function' 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O23SZ \
 ; RUN:     --check-prefix=CHECK-O3 --check-prefix=CHECK-EP-Peephole
 
 ; CHECK-O: Running pass: Annotation2Metadata
+; CHECK-O-NEXT: Running pass: CrossDSOCFIPass
 ; CHECK-O-NEXT: Running pass: GlobalDCEPass
 ; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}Module
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O23SZ-NEXT: Running pass: CallSiteSplittingPass on foo
 ; CHECK-O23SZ-NEXT: Running analysis: TargetLibraryAnalysis on foo
 ; CHECK-O23SZ-NEXT: Running analysis: TargetIRAnalysis on foo

 ; CHECK-O2-NEXT: Running pass: SLPVectorizerPass on foo
 ; CHECK-O3-NEXT: Running pass: SLPVectorizerPass on foo
 ; CHECK-OS-NEXT: Running pass: SLPVectorizerPass on foo
 ; CHECK-O23SZ-NEXT: Running pass: VectorCombinePass on foo
 ; CHECK-O23SZ-NEXT: Running pass: AlignmentFromAssumptionsPass on foo
 ; CHECK-O23SZ-NEXT: Running pass: InstCombinePass on foo
 ; CHECK-EP-Peephole-NEXT: Running pass: NoOpFunctionPass on foo
 ; CHECK-O23SZ-NEXT: Running pass: JumpThreadingPass on foo
-; CHECK-O23SZ-NEXT: Running pass: CrossDSOCFIPass
 ; CHECK-O23SZ-NEXT: Running pass: LowerTypeTestsPass
 ; CHECK-O-NEXT: Running pass: LowerTypeTestsPass
 ; CHECK-O23SZ-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O23SZ-NEXT: Running pass: EliminateAvailableExternallyPass
 ; CHECK-O23SZ-NEXT: Running pass: GlobalDCEPass
 ; CHECK-O-NEXT: Running pass: AnnotationRemarksPass on foo
 ; CHECK-O-NEXT: Running pass: PrintModulePass