[clang] [clang] Prioritze decl comments from macro expansion site (PR #65481)
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cfe-commits at lists.llvm.org
Thu Sep 7 02:11:28 PDT 2023
================
@@ -179,103 +179,38 @@ static SourceLocation getDeclLocForCommentSearch(const Decl *D,
isa<ClassTemplateSpecializationDecl>(D) ||
// Allow association with Y across {} in `typedef struct X {} Y`.
isa<TypedefDecl>(D))
- return D->getBeginLoc();
+ return {D->getBeginLoc()};
const SourceLocation DeclLoc = D->getLocation();
if (DeclLoc.isMacroID()) {
- // There are (at least) three types of macros we care about here.
- //
- // 1. Macros that are used in the definition of a type outside the macro,
- // with a comment attached at the macro call site.
- // ```
- // #define MAKE_NAME(Foo) Name##Foo
- //
- // /// Comment is here, where we use the macro.
- // struct MAKE_NAME(Foo) {
- // int a;
- // int b;
- // };
- // ```
- // 2. Macros that define whole things along with the comment.
- // ```
- // #define MAKE_METHOD(name) \
- // /** Comment is here, inside the macro. */ \
- // void name() {}
- //
- // struct S {
- // MAKE_METHOD(f)
- // }
- // ```
- // 3. Macros that both declare a type and name a decl outside the macro.
- // ```
- // /// Comment is here, where we use the macro.
- // typedef NS_ENUM(NSInteger, Size) {
- // SizeWidth,
- // SizeHeight
- // };
- // ```
- // In this case NS_ENUM declares am enum type, and uses the same name for
- // the typedef declaration that appears outside the macro. The comment
- // here should be applied to both declarations inside and outside the
- // macro.
- //
- // We have found a Decl name that comes from inside a macro, but
- // Decl::getLocation() returns the place where the macro is being called.
- // If the declaration (and not just the name) resides inside the macro,
- // then we want to map Decl::getLocation() into the macro to where the
- // declaration and its attached comment (if any) were written.
- //
- // This mapping into the macro is done by mapping the location to its
- // spelling location, however even if the declaration is inside a macro,
- // the name's spelling can come from a macro argument (case 2 above). In
- // this case mapping the location to the spelling location finds the
- // argument's position (at `f` in MAKE_METHOD(`f`) above), which is not
- // where the declaration and its comment are located.
- //
- // To avoid this issue, we make use of Decl::getBeginLocation() instead.
- // While the declaration's position is where the name is written, the
- // comment is always attached to the begining of the declaration, not to
- // the name.
- //
- // In the first case, the begin location of the decl is outside the macro,
- // at the location of `typedef`. This is where the comment is found as
- // well. The begin location is not inside a macro, so it's spelling
- // location is the same.
- //
- // In the second case, the begin location of the decl is the call to the
- // macro, at `MAKE_METHOD`. However its spelling location is inside the
- // the macro at the location of `void`. This is where the comment is found
- // again.
- //
- // In the third case, there's no correct single behaviour. We want to use
- // the comment outside the macro for the definition that's inside the macro.
- // There is also a definition outside the macro, and we want the comment to
- // apply to both. The cases we care about here is NS_ENUM() and
- // NS_OPTIONS(). In general, if an enum is defined inside a macro, we should
- // try to find the comment there.
-
- // This is handling case 3 for NS_ENUM() and NS_OPTIONS(), which define
- // enum types inside the macro.
- if (isa<EnumDecl>(D)) {
- SourceLocation MacroCallLoc = SourceMgr.getExpansionLoc(DeclLoc);
- if (auto BufferRef =
- SourceMgr.getBufferOrNone(SourceMgr.getFileID(MacroCallLoc));
- BufferRef.has_value()) {
- llvm::StringRef buffer = BufferRef->getBuffer().substr(
- SourceMgr.getFileOffset(MacroCallLoc));
- if (buffer.starts_with("NS_ENUM(") ||
- buffer.starts_with("NS_OPTIONS(")) {
- // We want to use the comment on the call to NS_ENUM and NS_OPTIONS
- // macros for the types defined inside the macros, which is at the
- // expansion location.
- return MacroCallLoc;
- }
- }
+ // When encountering definitions generated from a macro we need to try and
+ // findthe comment at the location of the expansion but if there is no
----------------
cor3ntin wrote:
```suggestion
// find the comment at the location of the expansion but if there is no
```
https://github.com/llvm/llvm-project/pull/65481
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