[clang-tools-extra] 6a77c4f - [clang-tidy] Fix inferred field note location (#202105)

[via cfe-commits]

Author: mygitljf
Date: 2026-06-08T10:37:16+08:00
New Revision: 6a77c4f36b6c7b05ea33bf886af5829ce234765e

URL: https://github.com/llvm/llvm-project/commit/6a77c4f36b6c7b05ea33bf886af5829ce234765e
DIFF: https://github.com/llvm/llvm-project/commit/6a77c4f36b6c7b05ea33bf886af5829ce234765e.diff

LOG: [clang-tidy] Fix inferred field note location (#202105)

Fixed the misleading note location for inferred ID-dependent fields.
Now the note points to the assignment that introduces the dependency,
not the field declaration.

Fixes #202077

Added: 
    

Modified: 
    clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.cpp
    clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.h
    clang-tools-extra/docs/ReleaseNotes.rst
    clang-tools-extra/test/clang-tidy/checkers/altera/id-dependent-backward-branch.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.cpp b/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.cpp
index 51f02b417bca6..82a02dd6e9344 100644
--- a/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.cpp
+++ b/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.cpp
@@ -50,11 +50,13 @@ void IdDependentBackwardBranchCheck::registerMatchers(MatchFinder *Finder) {
   // Bind all VarDecls that are assigned a value with a variable DeclRefExpr (in
   // case it is ID-dependent).
   Finder->addMatcher(
-      stmt(forEachDescendant(binaryOperator(
-          allOf(isAssignmentOperator(), hasRHS(RefVarOrField),
-                hasLHS(anyOf(
-                    declRefExpr(to(varDecl().bind("pot_tid_var"))),
-                    memberExpr(member(fieldDecl().bind("pot_tid_field"))))))))),
+      stmt(forEachDescendant(
+          binaryOperator(
+              allOf(isAssignmentOperator(), hasRHS(RefVarOrField),
+                    hasLHS(anyOf(declRefExpr(to(varDecl().bind("pot_tid_var"))),
+                                 memberExpr(member(
+                                     fieldDecl().bind("pot_tid_field")))))))
+              .bind("potential_assignment"))),
       this);
 
   // Second Matcher looks for branch statements inside of loops and bind on the
@@ -170,8 +172,8 @@ void IdDependentBackwardBranchCheck::saveIdDepVarFromPotentialReference(
 }
 
 void IdDependentBackwardBranchCheck::saveIdDepFieldFromPotentialReference(
-    const DeclRefExpr *RefExpr, const MemberExpr *MemExpr,
-    const FieldDecl *PotentialField) {
+    const Stmt *Statement, const DeclRefExpr *RefExpr,
+    const MemberExpr *MemExpr, const FieldDecl *PotentialField) {
   // If the field is already in IdDepFieldsMap, ignore it.
   if (IdDepFieldsMap.contains(PotentialField))
     return;
@@ -184,8 +186,8 @@ void IdDependentBackwardBranchCheck::saveIdDepFieldFromPotentialReference(
     // If field isn't ID-dependent, but RefVar is.
     if (IdDepVarsMap.contains(RefVar)) {
       StringStream << "variable " << RefVar->getNameAsString();
-      IdDepFieldsMap[PotentialField] = IdDependencyRecord(
-          PotentialField, PotentialField->getBeginLoc(), Message);
+      IdDepFieldsMap[PotentialField] =
+          IdDependencyRecord(PotentialField, Statement->getBeginLoc(), Message);
       return;
     }
   }
@@ -193,8 +195,8 @@ void IdDependentBackwardBranchCheck::saveIdDepFieldFromPotentialReference(
     const auto *RefField = dyn_cast<FieldDecl>(MemExpr->getMemberDecl());
     if (IdDepFieldsMap.contains(RefField)) {
       StringStream << "member " << RefField->getNameAsString();
-      IdDepFieldsMap[PotentialField] = IdDependencyRecord(
-          PotentialField, PotentialField->getBeginLoc(), Message);
+      IdDepFieldsMap[PotentialField] =
+          IdDependencyRecord(PotentialField, Statement->getBeginLoc(), Message);
     }
   }
 }
@@ -220,6 +222,8 @@ void IdDependentBackwardBranchCheck::check(
   const auto *Variable = Result.Nodes.getNodeAs<VarDecl>("tid_dep_var");
   const auto *Field = Result.Nodes.getNodeAs<FieldDecl>("tid_dep_field");
   const auto *Statement = Result.Nodes.getNodeAs<Stmt>("straight_assignment");
+  const auto *PotentialAssignment =
+      Result.Nodes.getNodeAs<Stmt>("potential_assignment");
   const auto *RefExpr = Result.Nodes.getNodeAs<DeclRefExpr>("assign_ref_var");
   const auto *MemExpr = Result.Nodes.getNodeAs<MemberExpr>("assign_ref_field");
   const auto *PotentialVar = Result.Nodes.getNodeAs<VarDecl>("pot_tid_var");
@@ -240,7 +244,8 @@ void IdDependentBackwardBranchCheck::check(
 
   // Save fields assigned to values of ID-dependent variables and fields.
   if ((RefExpr || MemExpr) && PotentialField)
-    saveIdDepFieldFromPotentialReference(RefExpr, MemExpr, PotentialField);
+    saveIdDepFieldFromPotentialReference(PotentialAssignment, RefExpr, MemExpr,
+                                         PotentialField);
 
   // The second part of the callback deals with checking if a branch inside a
   // loop is thread dependent.

diff  --git a/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.h b/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.h
index e8e22cf8c992a..6ce35e3b283c7 100644
--- a/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.h
+++ b/clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.h
@@ -61,7 +61,8 @@ class IdDependentBackwardBranchCheck : public ClangTidyCheck {
                                           const VarDecl *PotentialVar);
   /// Stores the location an ID-dependent field is created from a potential
   /// reference to another ID-dependent variable or field in IdDepFieldsMap.
-  void saveIdDepFieldFromPotentialReference(const DeclRefExpr *RefExpr,
+  void saveIdDepFieldFromPotentialReference(const Stmt *Statement,
+                                            const DeclRefExpr *RefExpr,
                                             const MemberExpr *MemExpr,
                                             const FieldDecl *PotentialField);
   /// Returns the loop type.

diff  --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 350ff0872c8e5..c369b1fd8b373 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -341,7 +341,7 @@ Changes in existing checks
 - Improved :doc:`altera-id-dependent-backward-branch
   <clang-tidy/checks/altera/id-dependent-backward-branch>` check by fixing false
   positives when ordinary variable or field assignments are used in loop
-  conditions.
+  conditions and note locations for inferred ID-dependent fields.
 
 - Improved :doc:`bugprone-argument-comment
   <clang-tidy/checks/bugprone/argument-comment>`:

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/altera/id-dependent-backward-branch.cpp b/clang-tools-extra/test/clang-tidy/checkers/altera/id-dependent-backward-branch.cpp
index c3eb6b6ea541a..9b52f0aac9704 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/altera/id-dependent-backward-branch.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/altera/id-dependent-backward-branch.cpp
@@ -103,14 +103,14 @@ void error() {
   InferredField.FieldFromVar = ThreadID * 2;
   while (j < InferredField.FieldFromVar) {
     // CHECK-NOTES: :[[@LINE-1]]:10: warning: backward branch (while loop) is ID-dependent due to member reference to 'FieldFromVar' and may cause performance degradation [altera-id-dependent-backward-branch]
-    // CHECK-NOTES: :[[@LINE-7]]:5: note: inferred assignment of ID-dependent member from ID-dependent variable ThreadID
+    // CHECK-NOTES: :[[@LINE-3]]:3: note: inferred assignment of ID-dependent member from ID-dependent variable ThreadID
     accumulator++;
   }
 
   InferredField.FieldFromField = Example.IDDepField;
   while (j < InferredField.FieldFromField) {
     // CHECK-NOTES: :[[@LINE-1]]:10: warning: backward branch (while loop) is ID-dependent due to member reference to 'FieldFromField' and may cause performance degradation [altera-id-dependent-backward-branch]
-    // CHECK-NOTES: :[[@LINE-13]]:5: note: inferred assignment of ID-dependent member from ID-dependent member IDDepField
+    // CHECK-NOTES: :[[@LINE-3]]:3: note: inferred assignment of ID-dependent member from ID-dependent member IDDepField
     accumulator++;
   }