[clang] [clang] fix lack comparison of declRefExpr in ASTStructuralEquivalence (PR #66041)

[via cfe-commits]

https://github.com/mzyKi updated https://github.com/llvm/llvm-project/pull/66041

>From a1635d87e4b56b501403f1add333c97b96b30a0f Mon Sep 17 00:00:00 2001
From: miaozhiyuan <miaozhiyuan at feysh.com>
Date: Tue, 12 Sep 2023 10:51:35 +0800
Subject: [PATCH] [clang][AST] fix lack comparison of declRefExpr in
 ASTStructuralEquivalence

---
 clang/docs/ReleaseNotes.rst                       | 2 ++
 clang/lib/AST/ASTStructuralEquivalence.cpp        | 9 +++++++++
 clang/unittests/AST/StructuralEquivalenceTest.cpp | 9 +++++++++
 3 files changed, 20 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 3cdad2f7b9f0e5a..d112a8701d387af 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -218,6 +218,8 @@ Bug Fixes in This Version
   (`#65156 <https://github.com/llvm/llvm-project/issues/65156>`_)
 - Clang no longer considers the loss of ``__unaligned`` qualifier from objects as
   an invalid conversion during method function overload resolution.
+- Fix lack of comparison of declRefExpr in ASTStructuralEquivalence
+  (`#66047 <https://github.com/llvm/llvm-project/issues/66047>`_)
 - Fix parser crash when dealing with ill-formed objective C++ header code. Fixes
   (`#64836 <https://github.com/llvm/llvm-project/issues/64836>`_)
 
diff --git a/clang/lib/AST/ASTStructuralEquivalence.cpp b/clang/lib/AST/ASTStructuralEquivalence.cpp
index 544420234ef0eb0..560d199620657a5 100644
--- a/clang/lib/AST/ASTStructuralEquivalence.cpp
+++ b/clang/lib/AST/ASTStructuralEquivalence.cpp
@@ -214,6 +214,15 @@ class StmtComparer {
     return E1->size() == E2->size();
   }
 
+  bool IsStmtEquivalent(const DeclRefExpr *DRE1, const DeclRefExpr *DRE2) {
+    const ValueDecl *Decl1 = DRE1->getDecl();
+    const ValueDecl *Decl2 = DRE2->getDecl();
+    if (!Decl1 || !Decl2)
+      return false;
+    return IsStructurallyEquivalent(Context, const_cast<ValueDecl *>(Decl1),
+                                    const_cast<ValueDecl *>(Decl2));
+  }
+
   bool IsStmtEquivalent(const DependentScopeDeclRefExpr *DE1,
                         const DependentScopeDeclRefExpr *DE2) {
     if (!IsStructurallyEquivalent(Context, DE1->getDeclName(),
diff --git a/clang/unittests/AST/StructuralEquivalenceTest.cpp b/clang/unittests/AST/StructuralEquivalenceTest.cpp
index 4e9f476659b9ee6..00041a2b2190089 100644
--- a/clang/unittests/AST/StructuralEquivalenceTest.cpp
+++ b/clang/unittests/AST/StructuralEquivalenceTest.cpp
@@ -2320,5 +2320,14 @@ TEST_F(StructuralEquivalenceStmtTest, UnresolvedLookup) {
   EXPECT_TRUE(testStructuralMatch(t));
 }
 
+TEST_F(StructuralEquivalenceStmtTest, DeclRefExpr) {
+  std::string Prefix = "enum Test { AAA, BBB };";
+  auto t = makeStmts(
+      Prefix + "void foo(int i) {if (i > 0) {i = AAA;} else {i = BBB;}}",
+      Prefix + "void foo(int i) {if (i > 0) {i = BBB;} else {i = AAA;}}",
+      Lang_CXX03, ifStmt());
+  EXPECT_FALSE(testStructuralMatch(t));
+}
+
 } // end namespace ast_matchers
 } // end namespace clang