[ThinLTO] Enable ThinLTO WholeProgramDevirt and LowerTypeTests in new PM

Summary:
Enable these passes for CFI and WPD in ThinLTO and LTO with the new pass
manager. Add a couple of tests for both PMs based on the clang tests
tools/clang/test/CodeGen/thinlto-distributed-cfi*.ll, but just test
through llvm-lto2 and not with distributed ThinLTO.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D49429

llvm-svn: 337461

5 files changed, 45 insertions, 29 deletions

diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 0ead3989941..eadbb410bd5 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -144,7 +144,9 @@ createTargetMachine(Config &Conf, const Target *TheTarget, Module &M) {
 }
 
 static void runNewPMPasses(Config &Conf, Module &Mod, TargetMachine *TM,
-                           unsigned OptLevel, bool IsThinLTO) {
+                           unsigned OptLevel, bool IsThinLTO,
+                           ModuleSummaryIndex *ExportSummary,
+                           const ModuleSummaryIndex *ImportSummary) {
   Optional<PGOOptions> PGOOpt;
   if (!Conf.SampleProfile.empty())
     PGOOpt = PGOOptions("", "", Conf.SampleProfile, false, true);
@@ -194,9 +196,10 @@ static void runNewPMPasses(Config &Conf, Module &Mod, TargetMachine *TM,
   }
 
   if (IsThinLTO)
-    MPM = PB.buildThinLTODefaultPipeline(OL, Conf.DebugPassManager);
+    MPM = PB.buildThinLTODefaultPipeline(OL, Conf.DebugPassManager,
+                                         ImportSummary);
   else
-    MPM = PB.buildLTODefaultPipeline(OL, Conf.DebugPassManager);
+    MPM = PB.buildLTODefaultPipeline(OL, Conf.DebugPassManager, ExportSummary);
   MPM.run(Mod, MAM);
 
   // FIXME (davide): verify the output.
@@ -279,7 +282,8 @@ bool opt(Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
     runNewPMCustomPasses(Mod, TM, Conf.OptPipeline, Conf.AAPipeline,
                          Conf.DisableVerify);
   else if (Conf.UseNewPM)
-    runNewPMPasses(Conf, Mod, TM, Conf.OptLevel, IsThinLTO);
+    runNewPMPasses(Conf, Mod, TM, Conf.OptLevel, IsThinLTO, ExportSummary,
+                   ImportSummary);
   else
     runOldPMPasses(Conf, Mod, TM, IsThinLTO, ExportSummary, ImportSummary);
   return !Conf.PostOptModuleHook || Conf.PostOptModuleHook(Task, Mod);
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index d4d66e06a02..eb04dcc8b6e 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -922,15 +922,28 @@ PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level,
   return MPM;
 }
 
-ModulePassManager
-PassBuilder::buildThinLTODefaultPipeline(OptimizationLevel Level,
-                                         bool DebugLogging) {
-  // FIXME: The summary index is not hooked in the new pass manager yet.
-  // When it's going to be hooked, enable WholeProgramDevirt and LowerTypeTest
-  // here.
-
+ModulePassManager PassBuilder::buildThinLTODefaultPipeline(
+    OptimizationLevel Level, bool DebugLogging,
+    const ModuleSummaryIndex *ImportSummary) {
   ModulePassManager MPM(DebugLogging);
 
+  if (ImportSummary) {
+    // These passes import type identifier resolutions for whole-program
+    // devirtualization and CFI. They must run early because other passes may
+    // disturb the specific instruction patterns that these passes look for,
+    // creating dependencies on resolutions that may not appear in the summary.
+    //
+    // For example, GVN may transform the pattern assume(type.test) appearing in
+    // two basic blocks into assume(phi(type.test, type.test)), which would
+    // transform a dependency on a WPD resolution into a dependency on a type
+    // identifier resolution for CFI.
+    //
+    // Also, WPD has access to more precise information than ICP and can
+    // devirtualize more effectively, so it should operate on the IR first.
+    MPM.addPass(WholeProgramDevirtPass(nullptr, ImportSummary));
+    MPM.addPass(LowerTypeTestsPass(nullptr, ImportSummary));
+  }
+
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
@@ -961,8 +974,9 @@ PassBuilder::buildLTOPreLinkDefaultPipeline(OptimizationLevel Level,
   return buildPerModuleDefaultPipeline(Level, DebugLogging);
 }
 
-ModulePassManager PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
-                                                       bool DebugLogging) {
+ModulePassManager
+PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level, bool DebugLogging,
+                                     ModuleSummaryIndex *ExportSummary) {
   assert(Level != O0 && "Must request optimizations for the default pipeline!");
   ModulePassManager MPM(DebugLogging);
 
@@ -1012,11 +1026,15 @@ ModulePassManager PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
 
   // Run whole program optimization of virtual call when the list of callees
   // is fixed.
-  MPM.addPass(WholeProgramDevirtPass());
+  MPM.addPass(WholeProgramDevirtPass(ExportSummary, nullptr));
 
   // Stop here at -O1.
-  if (Level == 1)
+  if (Level == 1) {
+    // The LowerTypeTestsPass needs to run to lower type metadata and the
+    // type.test intrinsics. The pass does nothing if CFI is disabled.
+    MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
     return MPM;
+  }
 
   // Optimize globals to try and fold them into constants.
   MPM.addPass(GlobalOptPass());
@@ -1125,12 +1143,7 @@ ModulePassManager PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
   // 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.
-  // Enable once we add support for the summary in the new PM.
-#if 0
-  MPM.addPass(LowerTypeTestsPass(Summary ? PassSummaryAction::Export :
-                                           PassSummaryAction::None,
-                                Summary));
-#endif
+  MPM.addPass(LowerTypeTestsPass(ExportSummary, nullptr));
 
   // Add late LTO optimization passes.
   // Delete basic blocks, which optimization passes may have killed.
@@ -1442,12 +1455,12 @@ bool PassBuilder::parseModulePass(ModulePassManager &MPM,
     } else if (Matches[1] == "thinlto-pre-link") {
       MPM.addPass(buildThinLTOPreLinkDefaultPipeline(L, DebugLogging));
     } else if (Matches[1] == "thinlto") {
-      MPM.addPass(buildThinLTODefaultPipeline(L, DebugLogging));
+      MPM.addPass(buildThinLTODefaultPipeline(L, DebugLogging, nullptr));
     } else if (Matches[1] == "lto-pre-link") {
       MPM.addPass(buildLTOPreLinkDefaultPipeline(L, DebugLogging));
     } else {
       assert(Matches[1] == "lto" && "Not one of the matched options!");
-      MPM.addPass(buildLTODefaultPipeline(L, DebugLogging));
+      MPM.addPass(buildLTODefaultPipeline(L, DebugLogging, nullptr));
     }
     return true;
   }
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 367f8ee3fb0..6ae93a47696 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -56,7 +56,7 @@ MODULE_PASS("instrprof", InstrProfiling())
 MODULE_PASS("internalize", InternalizePass())
 MODULE_PASS("invalidate<all>", InvalidateAllAnalysesPass())
 MODULE_PASS("ipsccp", IPSCCPPass())
-MODULE_PASS("lowertypetests", LowerTypeTestsPass())
+MODULE_PASS("lowertypetests", LowerTypeTestsPass(nullptr, nullptr))
 MODULE_PASS("name-anon-globals", NameAnonGlobalPass())
 MODULE_PASS("no-op-module", NoOpModulePass())
 MODULE_PASS("partial-inliner", PartialInlinerPass())
@@ -75,7 +75,7 @@ MODULE_PASS("rpo-functionattrs", ReversePostOrderFunctionAttrsPass())
 MODULE_PASS("sample-profile", SampleProfileLoaderPass())
 MODULE_PASS("strip-dead-prototypes", StripDeadPrototypesPass())
 MODULE_PASS("synthetic-counts-propagation", SyntheticCountsPropagation())
-MODULE_PASS("wholeprogramdevirt", WholeProgramDevirtPass())
+MODULE_PASS("wholeprogramdevirt", WholeProgramDevirtPass(nullptr, nullptr))
 MODULE_PASS("verify", VerifierPass())
 #undef MODULE_PASS
 
diff --git a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
index 9d6442b51ee..367b6282e24 100644
--- a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
+++ b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
@@ -2102,9 +2102,7 @@ bool LowerTypeTestsModule::lower() {
 
 PreservedAnalyses LowerTypeTestsPass::run(Module &M,
                                           ModuleAnalysisManager &AM) {
-  bool Changed = LowerTypeTestsModule(M, /*ExportSummary=*/nullptr,
-                                      /*ImportSummary=*/nullptr)
-                     .lower();
+  bool Changed = LowerTypeTestsModule(M, ExportSummary, ImportSummary).lower();
   if (!Changed)
     return PreservedAnalyses::all();
   return PreservedAnalyses::none();
diff --git a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
index 6a99ca17dfd..d65da2504db 100644
--- a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
+++ b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
@@ -611,7 +611,8 @@ PreservedAnalyses WholeProgramDevirtPass::run(Module &M,
   auto OREGetter = [&](Function *F) -> OptimizationRemarkEmitter & {
     return FAM.getResult<OptimizationRemarkEmitterAnalysis>(*F);
   };
-  if (!DevirtModule(M, AARGetter, OREGetter, nullptr, nullptr).run())
+  if (!DevirtModule(M, AARGetter, OREGetter, ExportSummary, ImportSummary)
+           .run())
     return PreservedAnalyses::all();
   return PreservedAnalyses::none();
 }