[PATCH] D80186: [Inliner] Update !associated metadata during inlining

[Petr Hosek via Phabricator via llvm-commits]

phosek created this revision.
phosek added reviewers: pcc, eugenis.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.
phosek added a child revision: D76802: [InstrProfiling] Use !associated metadata for counters, data and values.
phosek added a comment.

This is a prerequisite for D76802 <https://reviews.llvm.org/D76802> because `InstrProfiling` pass runs before inliner which can invalidate the metadata.


When inlining a function that has !associated metadata, update the
metadata to point to caller instead of callee.


https://reviews.llvm.org/D80186

Files:
  llvm/lib/Transforms/Utils/InlineFunction.cpp
  llvm/test/Transforms/Inline/inline-md-associated.ll


Index: llvm/test/Transforms/Inline/inline-md-associated.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/Inline/inline-md-associated.ll
@@ -0,0 +1,41 @@
+; RUN: opt < %s -inline --inline-threshold=0 -S | FileCheck %s
+
+; Test that the inliner updates the !associated metadata for inlined functions.
+
+; CHECK: @__foo_metadata = private global [1 x i64] zeroinitializer, align 8, !associated !0
+ at __foo_metadata = private global [1 x i64] zeroinitializer, align 8, !associated !0
+; CHECK: @__bar_metadata = private global [1 x i64] zeroinitializer, align 8, !associated !0
+ at __bar_metadata = private global [1 x i64] zeroinitializer, align 8, !associated !1
+; CHECK: @__baz_metadata = private global [1 x i64] zeroinitializer, align 8, !associated !1
+ at __baz_metadata = private global [1 x i64] zeroinitializer, align 8, !associated !2
+
+define void @foo() {
+  call void @bar(i1 true)
+  ret void
+}
+
+define internal void @bar(i1 %p) {
+  br i1 %p, label %bb1, label %bb2
+
+bb1:
+  call void @foo()
+  ret void
+
+bb2:
+  call void @bar(i1 true)
+  ret void
+}
+
+define void @baz() {
+; CHECK: call void @foo()
+  call void @bar(i1 true)
+; CHECK: call void @foo()
+  call void @bar(i1 false)
+  ret void
+}
+
+; CHECK: !0 = !{void ()* @foo}
+!0 = !{void ()* @foo}
+!1 = !{void (i1)* @bar}
+; CHECK: !1 = !{void ()* @baz}
+!2 = !{void ()* @baz}
Index: llvm/lib/Transforms/Utils/InlineFunction.cpp
===================================================================
--- llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1137,6 +1137,23 @@
   }
 }
 
+static void UpdateAssociatedMetadata(CallBase &CB) {
+  Module *M = CB.getModule();
+
+  Function *Callee = CB.getCalledFunction();
+  MDNode *CalleeMD = MDNode::get(CB.getContext(), ValueAsMetadata::get(Callee));
+  Function *Caller = CB.getFunction();
+  MDNode *CallerMD = MDNode::get(CB.getContext(), ValueAsMetadata::get(Caller));
+
+  for (GlobalVariable &GV : M->globals()) {
+    MDNode *MD = GV.getMetadata(LLVMContext::MD_associated);
+    if (!MD)
+      continue;
+    if (MD == CalleeMD)
+      GV.setMetadata(LLVMContext::MD_associated, CallerMD);
+  }
+}
+
 static bool MayContainThrowingOrExitingCall(Instruction *Begin,
                                             Instruction *End) {
 
@@ -1900,6 +1917,9 @@
     // Propagate llvm.mem.parallel_loop_access if necessary.
     PropagateParallelLoopAccessMetadata(CB, VMap);
 
+    // Adjust !associated metadata to point to caller instead of callee.
+    UpdateAssociatedMetadata(CB);
+
     // Register any cloned assumptions.
     if (IFI.GetAssumptionCache)
       for (BasicBlock &NewBlock :


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