[NFC][Utils] Extract CloneFunctionMetadataInto from CloneFunctionInto

[artempyanykh]

Stacked PRs:

• [Coro] Use DebugInfoCache to speed up cloning in CoroSplitPass #118630
• [Analysis] Add DebugInfoCache analysis #118629
• [Coro] Prebuild a module-level debug info set and share it between all coroutine clones #118628
• [Utils] Identity map module-level debug info on first use in CloneFunction* #118627
• [NFC][Utils] Eliminate DISubprogram set from BuildDebugInfoMDMap #118625
• [NFC][Utils] Extract CloneFunctionBodyInto from CloneFunctionInto #118624
• ->[NFC][Utils] Extract CloneFunctionMetadataInto from CloneFunctionInto #118623

---

[NFC][Utils] Extract CloneFunctionMetadataInto from CloneFunctionInto

Summary:
The new API expects the caller to populate the VMap. We need it this way
for a subsequent change around coroutine cloning.

Test Plan:
ninja check-llvm-unit check-llvm

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Artem Pianykh (artempyanykh)

Changes

[NFC][Utils] Extract CloneFunctionMetadataInto from CloneFunctionInto

Summary:
The new API expects the caller to populate the VMap. We need it this way
for a subsequent change around coroutine cloning.

Test Plan:
ninja check-llvm-unit check-llvm

---

Full diff: https://github.com/llvm/llvm-project/pull/118623.diff

2 Files Affected:

• (modified) llvm/include/llvm/Transforms/Utils/Cloning.h (+12)
• (modified) llvm/lib/Transforms/Utils/CloneFunction.cpp (+19-9)

diff --git a/llvm/include/llvm/Transforms/Utils/Cloning.h b/llvm/include/llvm/Transforms/Utils/Cloning.h
index 434089138bc521..698d773525e80b 100644
--- a/llvm/include/llvm/Transforms/Utils/Cloning.h
+++ b/llvm/include/llvm/Transforms/Utils/Cloning.h
@@ -182,6 +182,18 @@ void CloneFunctionAttributesInto(Function *NewFunc, const Function *OldFunc,
                                  ValueMapTypeRemapper *TypeMapper = nullptr,
                                  ValueMaterializer *Materializer = nullptr);
 
+/// Clone OldFunc's metadata into NewFunc.
+///
+/// The caller is expected to populate \p VMap beforehand and set an appropriate
+/// \p RemapFlag.
+///
+/// NOTE: This function doesn't clone !llvm.dbg.cu when cloning into a different
+/// module. Use CloneFunctionInto for that behavior.
+void CloneFunctionMetadataInto(Function *NewFunc, const Function *OldFunc,
+                               ValueToValueMapTy &VMap, RemapFlags RemapFlag,
+                               ValueMapTypeRemapper *TypeMapper = nullptr,
+                               ValueMaterializer *Materializer = nullptr);
+
 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
                                const Instruction *StartingInst,
                                ValueToValueMapTy &VMap, bool ModuleLevelChanges,
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 736c4a13045c14..4306e5d2abdd18 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -199,6 +199,22 @@ bool llvm::BuildDebugInfoMDMap(MDMapT &MD, CloneFunctionChangeType Changes,
   return ModuleLevelChanges;
 }
 
+void llvm::CloneFunctionMetadataInto(Function *NewFunc, const Function *OldFunc,
+                                     ValueToValueMapTy &VMap,
+                                     RemapFlags RemapFlag,
+                                     ValueMapTypeRemapper *TypeMapper,
+                                     ValueMaterializer *Materializer) {
+  // Duplicate the metadata that is attached to the cloned function.
+  // Subprograms/CUs/types that were already mapped to themselves won't be
+  // duplicated.
+  SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
+  OldFunc->getAllMetadata(MDs);
+  for (auto MD : MDs) {
+    NewFunc->addMetadata(MD.first, *MapMetadata(MD.second, VMap, RemapFlag,
+                                                TypeMapper, Materializer));
+  }
+}
+
 // Clone OldFunc into NewFunc, transforming the old arguments into references to
 // VMap values.
 void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
@@ -261,15 +277,9 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
       BuildDebugInfoMDMap(VMap.MD(), Changes, DIFinder, SPClonedWithinModule);
 
   const auto RemapFlag = ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges;
-  // Duplicate the metadata that is attached to the cloned function.
-  // Subprograms/CUs/types that were already mapped to themselves won't be
-  // duplicated.
-  SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
-  OldFunc->getAllMetadata(MDs);
-  for (auto MD : MDs) {
-    NewFunc->addMetadata(MD.first, *MapMetadata(MD.second, VMap, RemapFlag,
-                                                TypeMapper, Materializer));
-  }
+
+  CloneFunctionMetadataInto(NewFunc, OldFunc, VMap, RemapFlag, TypeMapper,
+                            Materializer);
 
   // Loop over all of the basic blocks in the function, cloning them as
   // appropriate.  Note that we save BE this way in order to handle cloning of

[felipepiovezan]

Can NewFunc or OldFunc be null? If not, we should make them references

[artempyanykh]

Both can't be null. Made them references.

[felipepiovezan]

Note that, in the context of this function, there is no "cloned function", it's either NewFunc or OldFunc.

That said, I this comment fits better in the documentation of the header, as there is important information here that callers should be aware

[artempyanykh]

Thanks! Moved relevant documentation bits into Cloning.h.