[CodeComplete] Expose helpers to get RawComment of completion result.

[ilya-biryukov]

Summary

Used in clangd, see D45999.

[ioeric]

This seems to do what we want for clangd, but we should also get the code owner or someone who knows the code better to take a look.

[ilya-biryukov]

Remove accidentally added changes that should be part of D46000

[ilya-biryukov]

In D46001#1077781, @ioeric wrote:

This seems to do what we want for clangd, but we should also get the code owner or someone who knows the code better to take a look.

Added @arphaman. Alex reviewed some of our code completion patches before.
This should give us enough coverage to make sure we don't go in the wrong direction.

If there's someone else who should be in the reviewers list, please don't hesitate to add them.

[ilya-biryukov]

@arphaman, friendly ping. In case you're the wrong person to review it, I'll try to find someone else.

[sammccall]

This is pretty small and seems unlikely to be controversial. I think it's OK to commit at this point, it's been a few weeks.

include/clang/Sema/CodeCompleteConsumer.h

1092

as in the other patch, I think ArgIndex is a better name for this parameter, when considering this function in isolation

[ilya-biryukov]

• Rebase onto head and remove \brief from the comments, it's gone upstream now
• Rename CurrentArg to ArgIndex

include/clang/Sema/CodeCompleteConsumer.h

 class FunctionDecl;
 class FunctionTemplateDecl;
 class IdentifierInfo;
 class LangOptions;
 class NamedDecl;
 class NestedNameSpecifier;
 class Preprocessor;
 class Sema;
+class RawComment;
 
 /// \brief Default priority values for code-completion results based
 /// on their kind.
 enum {
   /// \brief Priority for the next initialization in a constructor initializer
   /// list.
   CCP_NextInitializer = 7,
 
public:
 
   /// \brief Retrieve the allocator that will be used to allocate
   /// code completion strings.
   virtual CodeCompletionAllocator &getAllocator() = 0;
 
   virtual CodeCompletionTUInfo &getCodeCompletionTUInfo() = 0;
 };
 
+/// \brief Get the documentation comment used to produce
+/// CodeCompletionString::BriefComment for RK_Declaration.
+const RawComment *getCompletionComment(const ASTContext &Ctx,
+                                       const NamedDecl *Decl);
+
+/// \brief Get the documentation comment used to produce
+/// CodeCompletionString::BriefComment for RK_Pattern.
+const RawComment *getPatternCompletionComment(const ASTContext &Ctx,
+                                              const NamedDecl *Decl);
+
+/// \brief Get the documentation comment used to produce
+/// CodeCompletionString::BriefComment for OverloadCandidate.
+const RawComment *
+getParameterComment(const ASTContext &Ctx,
+                    const CodeCompleteConsumer::OverloadCandidate &Result,
+                    unsigned CurrentArg);
+
 /// \brief A simple code-completion consumer that prints the results it
 /// receives in a simple format.
 class PrintingCodeCompleteConsumer : public CodeCompleteConsumer {
   /// \brief The raw output stream.
   raw_ostream &OS;
 
   CodeCompletionTUInfo CCTUInfo;
 

lib/Sema/SemaCodeComplete.cpp

CodeCompletionResult::CreateCodeCompletionString(ASTContext &Ctx,
   PrintingPolicy Policy = getCompletionPrintingPolicy(Ctx, PP);
   if (Kind == RK_Pattern) {
     Pattern->Priority = Priority;
     Pattern->Availability = Availability;
     
     if (Declaration) {
       Result.addParentContext(Declaration->getDeclContext());
       Pattern->ParentName = Result.getParentName();
-      // Provide code completion comment for self.GetterName where
-      // GetterName is the getter method for a property with name
-      // different from the property name (declared via a property
-      // getter attribute.
-      const NamedDecl *ND = Declaration;
-      if (const ObjCMethodDecl *M = dyn_cast<ObjCMethodDecl>(ND))
-        if (M->isPropertyAccessor())
-          if (const ObjCPropertyDecl *PDecl = M->findPropertyDecl())
-            if (PDecl->getGetterName() == M->getSelector() &&
-                PDecl->getIdentifier() != M->getIdentifier()) {
-              if (const RawComment *RC = 
-                    Ctx.getRawCommentForAnyRedecl(M)) {
-                Result.addBriefComment(RC->getBriefText(Ctx));
-                Pattern->BriefComment = Result.getBriefComment();
-              }
-              else if (const RawComment *RC = 
-                         Ctx.getRawCommentForAnyRedecl(PDecl)) {
-                Result.addBriefComment(RC->getBriefText(Ctx));
-                Pattern->BriefComment = Result.getBriefComment();
-              }
-            }
-    }
+      if (const RawComment *RC =
+              getPatternCompletionComment(Ctx, Declaration)) {
     
     return Pattern;
   }
   
   if (Kind == RK_Keyword) {
     Result.AddTypedTextChunk(Keyword);
     return Result.TakeString();
   }
CodeCompletionResult::CreateCodeCompletionString(ASTContext &Ctx,
   }
   
   assert(Kind == RK_Declaration && "Missed a result kind?");
   const NamedDecl *ND = Declaration;
   Result.addParentContext(ND->getDeclContext());
 
   if (IncludeBriefComments) {
     // Add documentation comment, if it exists.
-    if (const RawComment *RC = Ctx.getRawCommentForAnyRedecl(ND)) {
+    if (const RawComment *RC = getCompletionComment(Ctx, Declaration)) {
       Result.addBriefComment(RC->getBriefText(Ctx));
     } 
-    else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(ND))
-      if (OMD->isPropertyAccessor())
-        if (const ObjCPropertyDecl *PDecl = OMD->findPropertyDecl())
-          if (const RawComment *RC = Ctx.getRawCommentForAnyRedecl(PDecl))
-            Result.addBriefComment(RC->getBriefText(Ctx));
   }
 
   if (StartsNestedNameSpecifier) {
     Result.AddTypedTextChunk(
                       Result.getAllocator().CopyString(ND->getNameAsString()));
     Result.AddTextChunk("::");
     return Result.TakeString();
   }
if (Qualifier)
     AddQualifierToCompletionString(Result, Qualifier, QualifierIsInformative, 
                                    Ctx, Policy);
 
   Result.AddTypedTextChunk(
                        Result.getAllocator().CopyString(ND->getNameAsString()));
   return Result.TakeString();
 }
 
+const RawComment *clang::getCompletionComment(const ASTContext &Ctx,
+                                              const NamedDecl *ND) {
+  if (!ND)
+    return nullptr;
+  if (auto *RC = Ctx.getRawCommentForAnyRedecl(ND))
+    return RC;
+
+  // Try to find comment from a property for ObjC methods.
+  const ObjCMethodDecl *M = dyn_cast<ObjCMethodDecl>(ND);
+  if (!M)
+    return nullptr;
+  const ObjCPropertyDecl *PDecl = M->findPropertyDecl();
+  if (!PDecl)
+    return nullptr;
+
+  return Ctx.getRawCommentForAnyRedecl(PDecl);
+}
+
+const RawComment *clang::getPatternCompletionComment(const ASTContext &Ctx,
+                                                     const NamedDecl *ND) {
+  const ObjCMethodDecl *M = dyn_cast_or_null<ObjCMethodDecl>(ND);
+  if (!M || !M->isPropertyAccessor())
+    return nullptr;
+
+  // Provide code completion comment for self.GetterName where
+  // GetterName is the getter method for a property with name
+  // different from the property name (declared via a property
+  // getter attribute.
+  const ObjCPropertyDecl *PDecl = M->findPropertyDecl();
+  if (!PDecl)
+    return nullptr;
+  if (PDecl->getGetterName() == M->getSelector() &&
+      PDecl->getIdentifier() != M->getIdentifier()) {
+    if (auto *RC = Ctx.getRawCommentForAnyRedecl(M))
+      return RC;
+    if (auto *RC = Ctx.getRawCommentForAnyRedecl(PDecl))
+      return RC;
+  }
+  return nullptr;
+}
+
+/// \brief Get the documentation comment used to produce
+/// CodeCompletionString::BriefComment.
+const RawComment *clang::getParameterComment(
+    const ASTContext &Ctx,
+    const CodeCompleteConsumer::OverloadCandidate &Result,
+    unsigned CurrentArg) {
+  auto FDecl = Result.getFunction();
+  if (!FDecl)
+    return nullptr;
+  if (CurrentArg < FDecl->getNumParams())
+    return Ctx.getRawCommentForAnyRedecl(FDecl->getParamDecl(CurrentArg));
+  return nullptr;
+}
+
 /// \brief Add function overload parameter chunks to the given code completion
 /// string.
 static void AddOverloadParameterChunks(ASTContext &Context,
                                        const PrintingPolicy &Policy,
                                        const FunctionDecl *Function,
                                        const FunctionProtoType *Prototype,
                                        CodeCompletionBuilder &Result,
                                        unsigned CurrentArg,
Result.AddResultTypeChunk(Result.getAllocator().CopyString(
       FT->getReturnType().getAsString(Policy)));
     Result.AddChunk(CodeCompletionString::CK_LeftParen);
     Result.AddChunk(CodeCompletionString::CK_CurrentParameter, "...");
     Result.AddChunk(CodeCompletionString::CK_RightParen);
     return Result.TakeString();
   }
 
   if (FDecl) {
-    if (IncludeBriefComments && CurrentArg < FDecl->getNumParams())
-      if (auto RC = S.getASTContext().getRawCommentForAnyRedecl(
-          FDecl->getParamDecl(CurrentArg)))
+    if (IncludeBriefComments) {
+      if (auto RC = getParameterComment(S.getASTContext(), *this, CurrentArg))
         Result.addBriefComment(RC->getBriefText(S.getASTContext()));
+    }
     AddResultTypeChunk(S.Context, Policy, FDecl, QualType(), Result);
     Result.AddTextChunk(
       Result.getAllocator().CopyString(FDecl->getNameAsString()));
   } else {
     Result.AddResultTypeChunk(
       Result.getAllocator().CopyString(
         Proto->getReturnType().getAsString(Policy)));
   }