[clang] [clang][dataflow] Fix smart pointer accessor caching to handle aliases (PR #124964)

[Jan Voung via cfe-commits]

https://github.com/jvoung created https://github.com/llvm/llvm-project/pull/124964

Check the canonical type in the matchers to handle aliases.
For example std::optional uses add_pointer_t<...>.


>From f5414bee931510d530c440f0590226367ba7913c Mon Sep 17 00:00:00 2001
From: Jan Voung <jvoung at gmail.com>
Date: Wed, 29 Jan 2025 18:07:55 +0000
Subject: [PATCH] [clang][dataflow] Fix smart pointer accessor caching to
 handle aliases

Check the canonical type in the matchers to handle aliases.
For example std::optional uses add_pointer_t<...>.
---
 .../SmartPointerAccessorCaching.cpp           | 19 ++++---
 .../SmartPointerAccessorCachingTest.cpp       | 52 +++++++++++++++++++
 2 files changed, 63 insertions(+), 8 deletions(-)

diff --git a/clang/lib/Analysis/FlowSensitive/SmartPointerAccessorCaching.cpp b/clang/lib/Analysis/FlowSensitive/SmartPointerAccessorCaching.cpp
index c58bd309545dbf..b73f9e2751449a 100644
--- a/clang/lib/Analysis/FlowSensitive/SmartPointerAccessorCaching.cpp
+++ b/clang/lib/Analysis/FlowSensitive/SmartPointerAccessorCaching.cpp
@@ -14,6 +14,7 @@ using ast_matchers::callee;
 using ast_matchers::cxxMemberCallExpr;
 using ast_matchers::cxxMethodDecl;
 using ast_matchers::cxxOperatorCallExpr;
+using ast_matchers::hasCanonicalType;
 using ast_matchers::hasName;
 using ast_matchers::hasOverloadedOperatorName;
 using ast_matchers::ofClass;
@@ -122,27 +123,29 @@ namespace clang::dataflow {
 ast_matchers::StatementMatcher isSmartPointerLikeOperatorStar() {
   return cxxOperatorCallExpr(
       hasOverloadedOperatorName("*"),
-      callee(cxxMethodDecl(parameterCountIs(0), returns(referenceType()),
+      callee(cxxMethodDecl(parameterCountIs(0),
+                           returns(hasCanonicalType(referenceType())),
                            ofClass(smartPointerClassWithGetOrValue()))));
 }
 
 ast_matchers::StatementMatcher isSmartPointerLikeOperatorArrow() {
   return cxxOperatorCallExpr(
       hasOverloadedOperatorName("->"),
-      callee(cxxMethodDecl(parameterCountIs(0), returns(pointerType()),
+      callee(cxxMethodDecl(parameterCountIs(0),
+                           returns(hasCanonicalType(pointerType())),
                            ofClass(smartPointerClassWithGetOrValue()))));
 }
 
 ast_matchers::StatementMatcher isSmartPointerLikeValueMethodCall() {
-  return cxxMemberCallExpr(callee(
-      cxxMethodDecl(parameterCountIs(0), returns(referenceType()),
-                    hasName("value"), ofClass(smartPointerClassWithValue()))));
+  return cxxMemberCallExpr(callee(cxxMethodDecl(
+      parameterCountIs(0), returns(hasCanonicalType(referenceType())),
+      hasName("value"), ofClass(smartPointerClassWithValue()))));
 }
 
 ast_matchers::StatementMatcher isSmartPointerLikeGetMethodCall() {
-  return cxxMemberCallExpr(callee(
-      cxxMethodDecl(parameterCountIs(0), returns(pointerType()), hasName("get"),
-                    ofClass(smartPointerClassWithGet()))));
+  return cxxMemberCallExpr(callee(cxxMethodDecl(
+      parameterCountIs(0), returns(hasCanonicalType(pointerType())),
+      hasName("get"), ofClass(smartPointerClassWithGet()))));
 }
 
 const FunctionDecl *
diff --git a/clang/unittests/Analysis/FlowSensitive/SmartPointerAccessorCachingTest.cpp b/clang/unittests/Analysis/FlowSensitive/SmartPointerAccessorCachingTest.cpp
index 3f75dff60ee5fc..18b9f80e32bbf1 100644
--- a/clang/unittests/Analysis/FlowSensitive/SmartPointerAccessorCachingTest.cpp
+++ b/clang/unittests/Analysis/FlowSensitive/SmartPointerAccessorCachingTest.cpp
@@ -190,5 +190,57 @@ TEST(SmartPointerAccessorCachingTest, MatchesWithValueAndNonConstOverloads) {
       isSmartPointerLikeValueMethodCall()));
 }
 
+TEST(SmartPointerAccessorCachingTest, MatchesWithTypeAliases) {
+  llvm::StringRef Decls(R"cc(
+    template <class T>
+    struct HasGetAndValue {
+      using pointer_t = T*;
+      using reference_t = T&;
+
+      const pointer_t operator->() const;
+      pointer_t operator->();
+      const reference_t operator*() const;
+      reference_t operator*();
+      const reference_t value() const;
+      reference_t value();
+      const pointer_t get() const;
+      pointer_t get();
+    };
+
+    struct S { int i; };
+  )cc");
+
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(HasGetAndValue<S> &NonConst) { return (*NonConst).i; }",
+      isSmartPointerLikeOperatorStar()));
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(const HasGetAndValue<S> &Const) { return (*Const).i; }",
+      isSmartPointerLikeOperatorStar()));
+  EXPECT_TRUE(matches(
+      Decls, "int target(HasGetAndValue<S> &NonConst) { return NonConst->i; }",
+      isSmartPointerLikeOperatorArrow()));
+  EXPECT_TRUE(matches(
+      Decls, "int target(const HasGetAndValue<S> &Const) { return Const->i; }",
+      isSmartPointerLikeOperatorArrow()));
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(HasGetAndValue<S> &NonConst) { return NonConst.value().i; }",
+      isSmartPointerLikeValueMethodCall()));
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(const HasGetAndValue<S> &Const) { return Const.value().i; }",
+      isSmartPointerLikeValueMethodCall()));
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(HasGetAndValue<S> &NonConst) { return NonConst.get()->i; }",
+      isSmartPointerLikeGetMethodCall()));
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(const HasGetAndValue<S> &Const) { return Const.get()->i; }",
+      isSmartPointerLikeGetMethodCall()));
+}
+
 } // namespace
 } // namespace clang::dataflow