clangd: Show argument names for function pointer struct fields

[Qwinci]

Show argument names in signature help when calling a function pointer struct field.

[llvmbot]

@llvm/pr-subscribers-clang-tools-extra
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clangd

Author: None (Qwinci)

Changes

Show argument names in signature help when calling a function pointer struct field.

---

Full diff: https://github.com/llvm/llvm-project/pull/69011.diff

2 Files Affected:

• (modified) clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp (+17)
• (modified) clang/lib/Sema/SemaCodeComplete.cpp (+11-1)

diff --git a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
index 766998eb4f3c719..bd88a0912b537d1 100644
--- a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
+++ b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
@@ -1462,6 +1462,23 @@ TEST(SignatureHelpTest, FunctionPointers) {
     typedef void (__stdcall *fn)(int x, int y);
     fn foo;
     int main() { foo(^); }
+  )cpp",
+      // Field of function pointer type
+      R"cpp(
+    struct S {
+      void (*foo)(int x, int y);
+    };
+    S s;
+    int main() { s.foo(^); }
+  )cpp",
+      // Field of function pointer typedef type
+      R"cpp(
+    typedef void (*fn)(int x, int y);
+    struct S {
+      fn foo;
+    };
+    S s;
+    int main() { s.foo(^); }
   )cpp"};
   for (auto Test : Tests)
     EXPECT_THAT(signatures(Test).signatures,
diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index adb82d3f6d176ab..5e3aed53fd8e218 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -6133,7 +6133,17 @@ ProduceSignatureHelp(Sema &SemaRef, MutableArrayRef<ResultCandidate> Candidates,
 // so that we can recover argument names from it.
 static FunctionProtoTypeLoc GetPrototypeLoc(Expr *Fn) {
   TypeLoc Target;
-  if (const auto *T = Fn->getType().getTypePtr()->getAs<TypedefType>()) {
+
+  if (const auto *ME = dyn_cast<MemberExpr>(Fn)) {
+    const auto *MD = ME->getMemberDecl();
+    if (const auto *FD = dyn_cast<FieldDecl>(MD)) {
+      if (const auto *T = FD->getType().getTypePtr()->getAs<TypedefType>()) {
+        Target = T->getDecl()->getTypeSourceInfo()->getTypeLoc();
+      } else {
+        Target = FD->getTypeSourceInfo()->getTypeLoc();
+      }
+    }
+  } else if (const auto *T = Fn->getType().getTypePtr()->getAs<TypedefType>()) {
     Target = T->getDecl()->getTypeSourceInfo()->getTypeLoc();
 
   } else if (const auto *DR = dyn_cast<DeclRefExpr>(Fn)) {

[HighCommander4]

Thanks for the patch!

[HighCommander4]

Thanks for the update! Looks good with a final nit.

[HighCommander4]

Thanks!