IR: Allow temporary nodes to become uniqued or distinct

Add `MDNode::replaceWithUniqued()` and `MDNode::replaceWithDistinct()`,
which mutate temporary nodes to become uniqued or distinct.  On uniquing
collisions, the unique version is returned and the node is deleted.

This takes advantage of temporary nodes being folded back in, and should
let me clean up some awkward logic in `MapMetadata()`.

llvm-svn: 226510

1 files changed, 79 insertions, 0 deletions

diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index de2ff8f81d9..730e8e87943 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -438,6 +438,85 @@ TEST_F(MDNodeTest, replaceResolvedOperand) {
   Temp->replaceAllUsesWith(nullptr);
 }
 
+TEST_F(MDNodeTest, replaceWithUniqued) {
+  auto *Empty = MDTuple::get(Context, None);
+  MDTuple *FirstUniqued;
+  {
+    Metadata *Ops[] = {Empty};
+    auto Temp = MDTuple::getTemporary(Context, Ops);
+    EXPECT_TRUE(Temp->isTemporary());
+
+    // Don't expect a collision.
+    auto *Current = Temp.get();
+    FirstUniqued = MDNode::replaceWithUniqued(std::move(Temp));
+    EXPECT_TRUE(FirstUniqued->isUniqued());
+    EXPECT_TRUE(FirstUniqued->isResolved());
+    EXPECT_EQ(Current, FirstUniqued);
+  }
+  {
+    Metadata *Ops[] = {Empty};
+    auto Temp = MDTuple::getTemporary(Context, Ops);
+    EXPECT_TRUE(Temp->isTemporary());
+
+    // Should collide with Uniqued above this time.
+    auto *Uniqued = MDNode::replaceWithUniqued(std::move(Temp));
+    EXPECT_TRUE(Uniqued->isUniqued());
+    EXPECT_TRUE(Uniqued->isResolved());
+    EXPECT_EQ(FirstUniqued, Uniqued);
+  }
+  {
+    auto Unresolved = MDTuple::getTemporary(Context, None);
+    Metadata *Ops[] = {Unresolved.get()};
+    auto Temp = MDTuple::getTemporary(Context, Ops);
+    EXPECT_TRUE(Temp->isTemporary());
+
+    // Shouldn't be resolved.
+    auto *Uniqued = MDNode::replaceWithUniqued(std::move(Temp));
+    EXPECT_TRUE(Uniqued->isUniqued());
+    EXPECT_FALSE(Uniqued->isResolved());
+
+    // Should be a different node.
+    EXPECT_NE(FirstUniqued, Uniqued);
+
+    // Should resolve when we update its node (note: be careful to avoid a
+    // collision with any other nodes above).
+    Uniqued->replaceOperandWith(0, nullptr);
+    EXPECT_TRUE(Uniqued->isResolved());
+  }
+}
+
+TEST_F(MDNodeTest, replaceWithDistinct) {
+  {
+    auto *Empty = MDTuple::get(Context, None);
+    Metadata *Ops[] = {Empty};
+    auto Temp = MDTuple::getTemporary(Context, Ops);
+    EXPECT_TRUE(Temp->isTemporary());
+
+    // Don't expect a collision.
+    auto *Current = Temp.get();
+    auto *Distinct = MDNode::replaceWithDistinct(std::move(Temp));
+    EXPECT_TRUE(Distinct->isDistinct());
+    EXPECT_TRUE(Distinct->isResolved());
+    EXPECT_EQ(Current, Distinct);
+  }
+  {
+    auto Unresolved = MDTuple::getTemporary(Context, None);
+    Metadata *Ops[] = {Unresolved.get()};
+    auto Temp = MDTuple::getTemporary(Context, Ops);
+    EXPECT_TRUE(Temp->isTemporary());
+
+    // Don't expect a collision.
+    auto *Current = Temp.get();
+    auto *Distinct = MDNode::replaceWithDistinct(std::move(Temp));
+    EXPECT_TRUE(Distinct->isDistinct());
+    EXPECT_TRUE(Distinct->isResolved());
+    EXPECT_EQ(Current, Distinct);
+
+    // Cleanup; required for teardown.
+    Unresolved->replaceAllUsesWith(nullptr);
+  }
+}
+
 typedef MetadataTest MDLocationTest;
 
 TEST_F(MDLocationTest, Overflow) {