[CodeComplete] Filter override completions by function name

Summary:
We put only part of the signature starting with a function name into "typed text"
chunks now, previously the whole signature was "typed text".

This leads to meaningful fuzzy match scores, giving better signals to
compare with other completion items.

Ideally, we would not display the result type to the user, but that requires adding
a new kind of completion chunk.

Reviewers: kadircet

Reviewed By: kadircet

Subscribers: jkorous, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62298

llvm-svn: 361623

3 files changed, 45 insertions, 28 deletions

diff --git a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
index e584597e7a9..8f8376e25bc 100644
--- a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
+++ b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
@@ -49,6 +49,9 @@ class IgnoreDiagnostics : public DiagnosticsConsumer {
 
 // GMock helpers for matching completion items.
 MATCHER_P(Named, Name, "") { return arg.Name == Name; }
+MATCHER_P(NameStartsWith, Prefix, "") {
+  return llvm::StringRef(arg.Name).startswith(Prefix);
+}
 MATCHER_P(Scope, S, "") { return arg.Scope == S; }
 MATCHER_P(Qualifier, Q, "") { return arg.RequiredQualifier == Q; }
 MATCHER_P(Labeled, Label, "") {
@@ -1946,10 +1949,13 @@ TEST(CompletionTest, SuggestOverrides) {
   };
   )cpp");
   const auto Results = completions(Text);
-  EXPECT_THAT(Results.Completions,
-              AllOf(Contains(Labeled("void vfunc(bool param, int p) override")),
-                    Contains(Labeled("void ttt(bool param) const override")),
-                    Not(Contains(Labeled("void vfunc(bool param) override")))));
+  EXPECT_THAT(
+      Results.Completions,
+      AllOf(Contains(AllOf(Labeled("void vfunc(bool param, int p) override"),
+                           NameStartsWith("vfunc"))),
+            Contains(AllOf(Labeled("void ttt(bool param) const override"),
+                           NameStartsWith("ttt"))),
+            Not(Contains(Labeled("void vfunc(bool param) override")))));
 }
 
 TEST(CompletionTest, OverridesNonIdentName) {
diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index e6c0b68b8d5..27e684252f5 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -37,6 +37,7 @@
 #include "llvm/Support/Path.h"
 #include <list>
 #include <map>
+#include <string>
 #include <vector>
 
 using namespace clang;
@@ -1828,19 +1829,6 @@ static void AddStaticAssertResult(CodeCompletionBuilder &Builder,
   Results.AddResult(CodeCompletionResult(Builder.TakeString()));
 }
 
-static void printOverrideString(llvm::raw_ostream &OS,
-                                CodeCompletionString *CCS) {
-  for (const auto &C : *CCS) {
-    if (C.Kind == CodeCompletionString::CK_Optional)
-      printOverrideString(OS, C.Optional);
-    else
-      OS << C.Text;
-    // Add a space after return type.
-    if (C.Kind == CodeCompletionString::CK_ResultType)
-      OS << ' ';
-  }
-}
-
 static void AddOverrideResults(ResultBuilder &Results,
                                const CodeCompletionContext &CCContext,
                                CodeCompletionBuilder &Builder) {
@@ -3162,19 +3150,42 @@ CodeCompletionString *CodeCompletionResult::CreateCodeCompletionString(
       PP, Ctx, Result, IncludeBriefComments, CCContext, Policy);
 }
 
+static void printOverrideString(const CodeCompletionString &CCS,
+                                std::string &BeforeName,
+                                std::string &NameAndSignature) {
+  bool SeenTypedChunk = false;
+  for (auto &Chunk : CCS) {
+    if (Chunk.Kind == CodeCompletionString::CK_Optional) {
+      assert(SeenTypedChunk && "optional parameter before name");
+      // Note that we put all chunks inside into NameAndSignature.
+      printOverrideString(*Chunk.Optional, NameAndSignature, NameAndSignature);
+      continue;
+    }
+    SeenTypedChunk |= Chunk.Kind == CodeCompletionString::CK_TypedText;
+    if (SeenTypedChunk)
+      NameAndSignature += Chunk.Text;
+    else
+      BeforeName += Chunk.Text;
+  }
+}
+
 CodeCompletionString *
 CodeCompletionResult::createCodeCompletionStringForOverride(
     Preprocessor &PP, ASTContext &Ctx, CodeCompletionBuilder &Result,
     bool IncludeBriefComments, const CodeCompletionContext &CCContext,
     PrintingPolicy &Policy) {
-  std::string OverrideSignature;
-  llvm::raw_string_ostream OS(OverrideSignature);
   auto *CCS = createCodeCompletionStringForDecl(PP, Ctx, Result,
                                                 /*IncludeBriefComments=*/false,
                                                 CCContext, Policy);
-  printOverrideString(OS, CCS);
-  OS << " override";
-  Result.AddTypedTextChunk(Result.getAllocator().CopyString(OS.str()));
+  std::string BeforeName;
+  std::string NameAndSignature;
+  // For overrides all chunks go into the result, none are informative.
+  printOverrideString(*CCS, BeforeName, NameAndSignature);
+  NameAndSignature += " override";
+
+  Result.AddTextChunk(Result.getAllocator().CopyString(BeforeName));
+  Result.AddChunk(CodeCompletionString::CK_HorizontalSpace);
+  Result.AddTypedTextChunk(Result.getAllocator().CopyString(NameAndSignature));
   return Result.TakeString();
 }
 
diff --git a/clang/test/CodeCompletion/overrides.cpp b/clang/test/CodeCompletion/overrides.cpp
index 06cff6af4d1..6645569d82a 100644
--- a/clang/test/CodeCompletion/overrides.cpp
+++ b/clang/test/CodeCompletion/overrides.cpp
@@ -11,23 +11,23 @@ void vfunc(bool param, int p) override;
 class C : public B {
  public:
   void vfunc(bool param) override;
-  void
+  vf
 };
 
-// Runs completion at ^void.
+// Runs completion at ^vf
 // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:14:3 %s -o - | FileCheck -check-prefix=CHECK-CC1 %s
 // CHECK-CC1: COMPLETION: Pattern : int ttt(bool param, int x = 3) const override{{$}}
 // CHECK-CC1: COMPLETION: Pattern : void vfunc(bool param, int p) override{{$}}
 // CHECK-CC1-NOT: COMPLETION: Pattern : void vfunc(bool param) override{{$}}
 //
-// Runs completion at vo^id.
+// Runs completion at vf^
 // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:14:5 %s -o - | FileCheck -check-prefix=CHECK-CC2 %s
-// CHECK-CC2: COMPLETION: Pattern : void vfunc(bool param, int p) override{{$}}
 // CHECK-CC2-NOT: COMPLETION: Pattern : int ttt(bool param, int x = 3) const override{{$}}
+// CHECK-CC2: COMPLETION: Pattern : void vfunc(bool param, int p) override{{$}}
 // CHECK-CC2-NOT: COMPLETION: Pattern : void vfunc(bool param) override{{$}}
 //
-// Runs completion at void ^.
-// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:14:8 %s -o - | FileCheck -check-prefix=CHECK-CC3 %s
+// Runs completion at void ^ on line 13.
+// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:13:8 %s -o - | FileCheck -check-prefix=CHECK-CC3 %s
 // CHECK-CC3-NOT: COMPLETION: Pattern : int ttt(bool param, int x = 3) const override{{$}}
 // CHECK-CC3-NOT: COMPLETION: Pattern : void vfunc(bool param, int p) override{{$}}
 // CHECK-CC3-NOT: COMPLETION: Pattern : void vfunc(bool param) override{{$}}