IR: Function summary extensions for whole-program devirtualization pass.

The summary information includes all uses of llvm.type.test and
llvm.type.checked.load intrinsics that can be used to devirtualize calls,
including any constant arguments for virtual constant propagation.

Differential Revision: https://reviews.llvm.org/D29734

llvm-svn: 294795

2 files changed, 87 insertions, 6 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index a46e49ccde8..fe73efef5a5 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -4848,6 +4848,10 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
   GlobalValueSummary *LastSeenSummary = nullptr;
   bool Combined = false;
   std::vector<GlobalValue::GUID> PendingTypeTests;
+  std::vector<FunctionSummary::VFuncId> PendingTypeTestAssumeVCalls,
+      PendingTypeCheckedLoadVCalls;
+  std::vector<FunctionSummary::ConstVCall> PendingTypeTestAssumeConstVCalls,
+      PendingTypeCheckedLoadConstVCalls;
 
   while (true) {
     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
@@ -4914,8 +4918,15 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
           IsOldProfileFormat, HasProfile);
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, std::move(Refs), std::move(Calls),
-          std::move(PendingTypeTests));
+          std::move(PendingTypeTests), std::move(PendingTypeTestAssumeVCalls),
+          std::move(PendingTypeCheckedLoadVCalls),
+          std::move(PendingTypeTestAssumeConstVCalls),
+          std::move(PendingTypeCheckedLoadConstVCalls));
       PendingTypeTests.clear();
+      PendingTypeTestAssumeVCalls.clear();
+      PendingTypeCheckedLoadVCalls.clear();
+      PendingTypeTestAssumeConstVCalls.clear();
+      PendingTypeCheckedLoadConstVCalls.clear();
       auto GUID = getGUIDFromValueId(ValueID);
       FS->setModulePath(TheIndex.addModulePath(ModulePath, 0)->first());
       FS->setOriginalName(GUID.second);
@@ -4989,8 +5000,15 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
       GlobalValue::GUID GUID = getGUIDFromValueId(ValueID).first;
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, std::move(Refs), std::move(Edges),
-          std::move(PendingTypeTests));
+          std::move(PendingTypeTests), std::move(PendingTypeTestAssumeVCalls),
+          std::move(PendingTypeCheckedLoadVCalls),
+          std::move(PendingTypeTestAssumeConstVCalls),
+          std::move(PendingTypeCheckedLoadConstVCalls));
       PendingTypeTests.clear();
+      PendingTypeTestAssumeVCalls.clear();
+      PendingTypeCheckedLoadVCalls.clear();
+      PendingTypeTestAssumeConstVCalls.clear();
+      PendingTypeCheckedLoadConstVCalls.clear();
       LastSeenSummary = FS.get();
       FS->setModulePath(ModuleIdMap[ModuleId]);
       TheIndex.addGlobalValueSummary(GUID, std::move(FS));
@@ -5054,6 +5072,28 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
                               Record.end());
       break;
     }
+    case bitc::FS_TYPE_TEST_ASSUME_VCALLS: {
+      assert(PendingTypeTestAssumeVCalls.empty());
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        PendingTypeTestAssumeVCalls.push_back({Record[I], Record[I+1]});
+      break;
+    }
+    case bitc::FS_TYPE_CHECKED_LOAD_VCALLS: {
+      assert(PendingTypeCheckedLoadVCalls.empty());
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        PendingTypeCheckedLoadVCalls.push_back({Record[I], Record[I+1]});
+      break;
+    }
+    case bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL: {
+      PendingTypeTestAssumeConstVCalls.push_back(
+          {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
+      break;
+    }
+    case bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL: {
+      PendingTypeCheckedLoadConstVCalls.push_back(
+          {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
+      break;
+    }
     }
   }
   llvm_unreachable("Exit infinite loop");
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 4eac89c37a5..1281fca5f69 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -3368,6 +3368,49 @@ void IndexBitcodeWriter::writeModStrings() {
   Stream.ExitBlock();
 }
 
+/// Write the function type metadata related records that need to appear before
+/// a function summary entry (whether per-module or combined).
+static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
+                                             FunctionSummary *FS) {
+  if (!FS->type_tests().empty())
+    Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+
+  SmallVector<uint64_t, 64> Record;
+
+  auto WriteVFuncIdVec = [&](uint64_t Ty,
+                             ArrayRef<FunctionSummary::VFuncId> VFs) {
+    if (VFs.empty())
+      return;
+    Record.clear();
+    for (auto &VF : VFs) {
+      Record.push_back(VF.GUID);
+      Record.push_back(VF.Offset);
+    }
+    Stream.EmitRecord(Ty, Record);
+  };
+
+  WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
+                  FS->type_test_assume_vcalls());
+  WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
+                  FS->type_checked_load_vcalls());
+
+  auto WriteConstVCallVec = [&](uint64_t Ty,
+                                ArrayRef<FunctionSummary::ConstVCall> VCs) {
+    for (auto &VC : VCs) {
+      Record.clear();
+      Record.push_back(VC.VFunc.GUID);
+      Record.push_back(VC.VFunc.Offset);
+      Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
+      Stream.EmitRecord(Ty, Record);
+    }
+  };
+
+  WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
+                     FS->type_test_assume_const_vcalls());
+  WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
+                     FS->type_checked_load_const_vcalls());
+}
+
 // Helper to emit a single function summary record.
 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
@@ -3376,8 +3419,7 @@ void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
   NameVals.push_back(ValueID);
 
   FunctionSummary *FS = cast<FunctionSummary>(Summary);
-  if (!FS->type_tests().empty())
-    Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+  writeFunctionTypeMetadataRecords(Stream, FS);
 
   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
   NameVals.push_back(FS->instCount());
@@ -3637,8 +3679,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     }
 
     auto *FS = cast<FunctionSummary>(S);
-    if (!FS->type_tests().empty())
-      Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+    writeFunctionTypeMetadataRecords(Stream, FS);
 
     NameVals.push_back(ValueId);
     NameVals.push_back(Index.getModuleId(FS->modulePath()));