IR: Function summary representation for type tests.

Each function summary has an attached list of type identifier GUIDs. The
idea is that during the regular LTO phase we would match these GUIDs to type
identifiers defined by the regular LTO module and store the resolutions in
a top-level "type identifier summary" (which will be implemented separately).

Differential Revision: https://reviews.llvm.org/D27967

llvm-svn: 290280

1 files changed, 28 insertions, 6 deletions

diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
index d5ceb18b951..cc256f9c829 100644
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Analysis/IndirectCallPromotionAnalysis.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/ProfileSummaryInfo.h"
+#include "llvm/Analysis/TypeMetadataUtils.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/InstIterator.h"
@@ -92,6 +93,7 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
   // counts for all static calls to a given callee.
   MapVector<ValueInfo, CalleeInfo> CallGraphEdges;
   SetVector<ValueInfo> RefEdges;
+  SetVector<GlobalValue::GUID> TypeTests;
   ICallPromotionAnalysis ICallAnalysis;
 
   bool HasInlineAsmMaybeReferencingInternal = false;
@@ -123,11 +125,29 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
         assert(!CalledFunction && "Expected null called function in callsite for alias");
         CalledFunction = dyn_cast<Function>(GA->getBaseObject());
       }
-      // Check if this is a direct call to a known function.
+      // Check if this is a direct call to a known function or a known
+      // intrinsic, or an indirect call with profile data.
       if (CalledFunction) {
-        // Skip intrinsics.
-        if (CalledFunction->isIntrinsic())
-          continue;
+        if (CalledFunction->isIntrinsic()) {
+          if (CalledFunction->getIntrinsicID() != Intrinsic::type_test)
+            continue;
+          // Produce a summary from type.test intrinsics. We only summarize
+          // type.test intrinsics that are used other than by an llvm.assume
+          // intrinsic. Intrinsics that are assumed are relevant only to the
+          // devirtualization pass, not the type test lowering pass.
+          bool HasNonAssumeUses = llvm::any_of(CI->uses(), [](const Use &CIU) {
+            auto *AssumeCI = dyn_cast<CallInst>(CIU.getUser());
+            if (!AssumeCI)
+              return true;
+            Function *F = AssumeCI->getCalledFunction();
+            return !F || F->getIntrinsicID() != Intrinsic::assume;
+          });
+          if (HasNonAssumeUses) {
+            auto *TypeMDVal = cast<MetadataAsValue>(CI->getArgOperand(1));
+            if (auto *TypeId = dyn_cast<MDString>(TypeMDVal->getMetadata()))
+              TypeTests.insert(GlobalValue::getGUID(TypeId->getString()));
+          }
+        }
         // We should have named any anonymous globals
         assert(CalledFunction->hasName());
         auto ScaledCount = BFI ? BFI->getBlockProfileCount(&BB) : None;
@@ -160,7 +180,8 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
 
   GlobalValueSummary::GVFlags Flags(F);
   auto FuncSummary = llvm::make_unique<FunctionSummary>(
-      Flags, NumInsts, RefEdges.takeVector(), CallGraphEdges.takeVector());
+      Flags, NumInsts, RefEdges.takeVector(), CallGraphEdges.takeVector(),
+      TypeTests.takeVector());
   if (HasInlineAsmMaybeReferencingInternal)
     FuncSummary->setHasInlineAsmMaybeReferencingInternal();
   Index.addGlobalValueSummary(F.getName(), std::move(FuncSummary));
@@ -280,7 +301,8 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex(
             std::unique_ptr<FunctionSummary> Summary =
                 llvm::make_unique<FunctionSummary>(
                     GVFlags, 0, ArrayRef<ValueInfo>{},
-                    ArrayRef<FunctionSummary::EdgeTy>{});
+                    ArrayRef<FunctionSummary::EdgeTy>{},
+                    ArrayRef<GlobalValue::GUID>{});
             Summary->setNoRename();
             Index.addGlobalValueSummary(Name, std::move(Summary));
           } else {