[clang-tidy][NFC] Expose HeuristicResolver::lookupDependentName() and use it in StandaloneEmptyCheck

[HighCommander4]

The use replaces CXXRecordDecl::lookupDependentName() which HeuristicResolver aims to supersede.

[llvmbot]

@llvm/pr-subscribers-clang-tidy

@llvm/pr-subscribers-clang

Author: Nathan Ridge (HighCommander4)

Changes

The use replaces CXXRecordDecl::lookupDependentName() which HeuristicResolver aims to supersede.

---

Full diff: https://github.com/llvm/llvm-project/pull/128391.diff

4 Files Affected:

• (modified) clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt (+1)
• (modified) clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp (+5-4)
• (modified) clang/include/clang/Sema/HeuristicResolver.h (+7)
• (modified) clang/lib/Sema/HeuristicResolver.cpp (+8-10)

diff --git a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
index e8309c68b7fca..cad6b456fc268 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -117,6 +117,7 @@ clang_target_link_libraries(clangTidyBugproneModule
   clangASTMatchers
   clangBasic
   clangLex
+  clangSema
   clangTooling
   clangTransformer
   )
diff --git a/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
index 2bce72cca98c6..a1d7b9931e419 100644
--- a/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
@@ -20,6 +20,7 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Lex/Lexer.h"
+#include "clang/Sema/HeuristicResolver.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Casting.h"
@@ -125,8 +126,8 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
     DeclarationName Name =
         Context.DeclarationNames.getIdentifier(&Context.Idents.get("clear"));
 
-    auto Candidates = MemberCall->getRecordDecl()->lookupDependentName(
-        Name, [](const NamedDecl *ND) {
+    auto Candidates = HeuristicResolver(Context).lookupDependentName(
+        MemberCall->getRecordDecl(), Name, [](const NamedDecl *ND) {
           return isa<CXXMethodDecl>(ND) &&
                  llvm::cast<CXXMethodDecl>(ND)->getMinRequiredArguments() ==
                      0 &&
@@ -174,8 +175,8 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
     DeclarationName Name =
         Context.DeclarationNames.getIdentifier(&Context.Idents.get("clear"));
 
-    auto Candidates =
-        ArgRecordDecl->lookupDependentName(Name, [](const NamedDecl *ND) {
+    auto Candidates = HeuristicResolver(Context).lookupDependentName(
+        ArgRecordDecl, Name, [](const NamedDecl *ND) {
           return isa<CXXMethodDecl>(ND) &&
                  llvm::cast<CXXMethodDecl>(ND)->getMinRequiredArguments() ==
                      0 &&
diff --git a/clang/include/clang/Sema/HeuristicResolver.h b/clang/include/clang/Sema/HeuristicResolver.h
index 3760003aab89f..f511815b40199 100644
--- a/clang/include/clang/Sema/HeuristicResolver.h
+++ b/clang/include/clang/Sema/HeuristicResolver.h
@@ -69,6 +69,13 @@ class HeuristicResolver {
   QualType
   resolveNestedNameSpecifierToType(const NestedNameSpecifier *NNS) const;
 
+  // Perform an imprecise lookup of a dependent name in `RD`.
+  // This function does not follow strict semantic rules and should be used
+  // only when lookup rules can be relaxed, e.g. indexing.
+  std::vector<const NamedDecl *>
+  lookupDependentName(CXXRecordDecl *RD, DeclarationName Name,
+                      llvm::function_ref<bool(const NamedDecl *ND)> Filter);
+
   // Given the type T of a dependent expression that appears of the LHS of a
   // "->", heuristically find a corresponding pointee type in whose scope we
   // could look up the name appearing on the RHS.
diff --git a/clang/lib/Sema/HeuristicResolver.cpp b/clang/lib/Sema/HeuristicResolver.cpp
index 3af4d001d6c1a..7aecd2a73b539 100644
--- a/clang/lib/Sema/HeuristicResolver.cpp
+++ b/clang/lib/Sema/HeuristicResolver.cpp
@@ -44,6 +44,9 @@ class HeuristicResolverImpl {
       const DependentTemplateSpecializationType *DTST);
   QualType resolveNestedNameSpecifierToType(const NestedNameSpecifier *NNS);
   QualType getPointeeType(QualType T);
+  std::vector<const NamedDecl *>
+  lookupDependentName(CXXRecordDecl *RD, DeclarationName Name,
+                      llvm::function_ref<bool(const NamedDecl *ND)> Filter);
 
 private:
   ASTContext &Ctx;
@@ -83,16 +86,6 @@ class HeuristicResolverImpl {
   // during simplification, and the operation fails if no pointer type is found.
   QualType simplifyType(QualType Type, const Expr *E, bool UnwrapPointer);
 
-  // This is a reimplementation of CXXRecordDecl::lookupDependentName()
-  // so that the implementation can call into other HeuristicResolver helpers.
-  // FIXME: Once HeuristicResolver is upstreamed to the clang libraries
-  // (https://github.com/clangd/clangd/discussions/1662),
-  // CXXRecordDecl::lookupDepenedentName() can be removed, and its call sites
-  // can be modified to benefit from the more comprehensive heuristics offered
-  // by HeuristicResolver instead.
-  std::vector<const NamedDecl *>
-  lookupDependentName(CXXRecordDecl *RD, DeclarationName Name,
-                      llvm::function_ref<bool(const NamedDecl *ND)> Filter);
   bool findOrdinaryMemberInDependentClasses(const CXXBaseSpecifier *Specifier,
                                             CXXBasePath &Path,
                                             DeclarationName Name);
@@ -539,6 +532,11 @@ QualType HeuristicResolver::resolveNestedNameSpecifierToType(
     const NestedNameSpecifier *NNS) const {
   return HeuristicResolverImpl(Ctx).resolveNestedNameSpecifierToType(NNS);
 }
+std::vector<const NamedDecl *> HeuristicResolver::lookupDependentName(
+    CXXRecordDecl *RD, DeclarationName Name,
+    llvm::function_ref<bool(const NamedDecl *ND)> Filter) {
+  return HeuristicResolverImpl(Ctx).lookupDependentName(RD, Name, Filter);
+}
 const QualType HeuristicResolver::getPointeeType(QualType T) const {
   return HeuristicResolverImpl(Ctx).getPointeeType(T);
 }

[HighCommander4]

Note: this is the last remaining use of CXXRecordDecl::lookupDependentName(). I plan to remove it in a follow-up patch.

[HighCommander4]

Note: this is the last remaining use of CXXRecordDecl::lookupDependentName(). I plan to remove it in a follow-up patch.

The follow-up patch is #128392.

[HerrCai0907]

LGTM as temporary solution
But clang-tidy actually do not want to reply on Sema. I take a look briefly about HeuristicResolver, it looks like not related to other Sema parts.
Is it possible to move the whole HeuristicResolver out of Sema lib to AST?

[HighCommander4]

I take a look briefly about HeuristicResolver, it looks like not related to other Sema parts. Is it possible to move the whole HeuristicResolver out of Sema lib to AST?

In future enhancements to HeuristicResolver, I would like to implement optional heuristics that make use of Sema. I envisioned the dependency on Sema being optional, such that clients who do not have one can continue to construct a HeursiticResolver without passing in a Sema.