[IR] Make TypeFinder check function metadata attachments.

[bartell]

Summary

Fixes PR39237.

lib/IR/TypeFinder.cpp

void TypeFinder::run(const Module &M, bool onlyNamed) {
   // Get types from aliases.
   for (const auto &A : M.aliases()) {
     incorporateType(A.getType());
     if (const Value *Aliasee = A.getAliasee())
       incorporateValue(Aliasee);
   }
 
   // Get types from functions.
-  SmallVector<std::pair<unsigned, MDNode *>, 4> MDForInst;
+  SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
   for (const Function &FI : M) {
     incorporateType(FI.getType());
 
     for (const Use &U : FI.operands())
       incorporateValue(U.get());
 
+    // Incorporate types hiding in metadata.
+    FI.getAllMetadata(MDs);
+    for (const auto &MD : MDs)
+      incorporateMDNode(MD.second);
+    MDs.clear();
+
     // First incorporate the arguments.
     for (const auto &A : FI.args())
       incorporateValue(&A);
 
     for (const BasicBlock &BB : FI)
       for (const Instruction &I : BB) {
         // Incorporate the type of the instruction.
         incorporateType(I.getType());
 
         // Incorporate non-instruction operand types. (We are incorporating all
         // instructions with this loop.)
         for (const auto &O : I.operands())
           if (&*O && !isa<Instruction>(&*O))
             incorporateValue(&*O);
 
         // Incorporate types hiding in metadata.
-        I.getAllMetadataOtherThanDebugLoc(MDForInst);
-        for (const auto &MD : MDForInst)
+        I.getAllMetadataOtherThanDebugLoc(MDs);
+        for (const auto &MD : MDs)
           incorporateMDNode(MD.second);
-        MDForInst.clear();
+        MDs.clear();
       }
   }
 
   for (const auto &NMD : M.named_metadata())
     for (const auto &MDOp : NMD.operands())
       incorporateMDNode(MDOp);
 }
 

unittests/IR/CMakeLists.txt

add_llvm_unittest(IRTests
   LegacyPassManagerTest.cpp
   MDBuilderTest.cpp
   ManglerTest.cpp
   MetadataTest.cpp
   ModuleTest.cpp
   PassManagerTest.cpp
   PatternMatch.cpp
   TypeBuilderTest.cpp
+  TypeFinderTest.cpp
   TypesTest.cpp
   UseTest.cpp
   UserTest.cpp
   ValueHandleTest.cpp
   ValueMapTest.cpp
   ValueTest.cpp
   VerifierTest.cpp
   WaymarkTest.cpp
   )

unittests/IR/TypeFinderTest.cpp

+//===- llvm/unittest/IR/TypeFinderTest.cpp - TypeFinder unit tests --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/TypeFinder.h"
+
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using ::testing::UnorderedElementsAre;
+
+namespace {
+
+TEST(TypeFinderTest, FunctionMetadata) {
+  LLVMContext C;
+
+  // PR39237
+  Module M("Test", C);
+  Function *F = cast<Function>(M.getOrInsertFunction(
+      "foo", FunctionType::get(Type::getVoidTy(C), None, false)));
+  StructType *Struct = StructType::create(C, "FooBar");
+  Metadata *Value = ConstantAsMetadata::get(ConstantAggregateZero::get(Struct));
+  MDNode *Node = MDNode::get(C, Value);
+  F->setMetadata("bar", Node);
+
+  TypeFinder Finder;
+  Finder.run(M, /*onlyNamed*/ false);
+  EXPECT_THAT(Finder, UnorderedElementsAre(Struct));
+}
+
+} // end anonymous namespace