[NFC][Cloning] Simplify the flow in FindDebugInfoToIdentityMap

[artempyanykh]

Stacked PRs:

• [NFC][Cloning] Move DebugInfoFinder decl closer to its place of usage #129154
• [NFC][Cloning] Clean up comments in CloneFunctionInto #129153
• [NFC][Cloning] Remove now unused CollectDebugInfoForCloning #129152
• [NFC][Cloning] Remove now unused FindDebugInfoToIdentityMap #129151
• [NFC][Coro] Remove now unused CommonDebugInfo in CoroSplit #129150
• [NFC][Coro] Use CloneFunctionInto for coroutine cloning instead of CloneFunction<Part> #129149
• [NFC][Cloning] Replace DIFinder usage in CloneFunctionInto with a MetadataPredicate #129148
• [NFC][Cloning] Replace IdentityMD set with a predicate in ValueMapper #129147
• [NFC][Cloning] Make DifferentModule case more obvious in CollectDebugInfoForCloning #129146
• [NFC][Cloning] Add a helper to collect debug info from instructions #129145
• ->[NFC][Cloning] Simplify the flow in FindDebugInfoToIdentityMap #129144
• [NFC][Cloning] Make ClonedModule case more obvious in CollectDebugInfoForCloning #129143

---

[NFC][Cloning] Simplify the flow in FindDebugInfoToIdentityMap

Summary:
The new flow should make it more clear what is happening in cases of
Different of Cloned modules.

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

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Artem Pianykh (artempyanykh)

Changes

[NFC][Cloning] Simplify the flow in FindDebugInfoToIdentityMap

Summary:
The new flow should make it more clear what is happening in cases of
Different of Cloned modules.

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

---

Full diff: https://github.com/llvm/llvm-project/pull/129144.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Utils/CloneFunction.cpp (+16-16)

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 9267930027c04..5a5b84c8e0a3c 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -160,21 +160,25 @@ MetadataSetTy
 llvm::FindDebugInfoToIdentityMap(CloneFunctionChangeType Changes,
                                  DebugInfoFinder &DIFinder,
                                  DISubprogram *SPClonedWithinModule) {
+  if (Changes >= CloneFunctionChangeType::DifferentModule)
+    return {};
+
+  if (DIFinder.subprogram_count() == 0)
+    assert(!SPClonedWithinModule &&
+           "Subprogram should be in DIFinder->subprogram_count()...");
+
   MetadataSetTy MD;
 
-  if (Changes < CloneFunctionChangeType::DifferentModule &&
-      DIFinder.subprogram_count() > 0) {
-    // Avoid cloning types, compile units, and (other) subprograms.
-    for (DISubprogram *ISP : DIFinder.subprograms()) {
-      if (ISP != SPClonedWithinModule)
-        MD.insert(ISP);
-    }
+  // Avoid cloning types, compile units, and (other) subprograms.
+  for (DISubprogram *ISP : DIFinder.subprograms())
+    if (ISP != SPClonedWithinModule)
+      MD.insert(ISP);
 
-    // If a subprogram isn't going to be cloned skip its lexical blocks as well.
-    for (DIScope *S : DIFinder.scopes()) {
-      auto *LScope = dyn_cast<DILocalScope>(S);
-      if (LScope && LScope->getSubprogram() != SPClonedWithinModule)
-        MD.insert(S);
+  // If a subprogram isn't going to be cloned skip its lexical blocks as well.
+  for (DIScope *S : DIFinder.scopes()) {
+    auto *LScope = dyn_cast<DILocalScope>(S);
+    if (LScope && LScope->getSubprogram() != SPClonedWithinModule)
+      MD.insert(S);
     }
 
     for (DICompileUnit *CU : DIFinder.compile_units())
@@ -182,10 +186,6 @@ llvm::FindDebugInfoToIdentityMap(CloneFunctionChangeType Changes,
 
     for (DIType *Type : DIFinder.types())
       MD.insert(Type);
-  } else {
-    assert(!SPClonedWithinModule &&
-           "Subprogram should be in DIFinder->subprogram_count()...");
-  }
 
   return MD;
 }

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 25c46523123edfc7f65f37a286fb3d2b7ac0c864 eefce0296241b86dfa6c6e177c6098dda6296bf3 --extensions cpp -- llvm/lib/Transforms/Utils/CloneFunction.cpp

View the diff from clang-format here.

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 5a5b84c8e0..7a309f7390 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -179,7 +179,7 @@ llvm::FindDebugInfoToIdentityMap(CloneFunctionChangeType Changes,
     auto *LScope = dyn_cast<DILocalScope>(S);
     if (LScope && LScope->getSubprogram() != SPClonedWithinModule)
       MD.insert(S);
-    }
+  }
 
     for (DICompileUnit *CU : DIFinder.compile_units())
       MD.insert(CU);