[alpha.webkit.UncountedCallArgsChecker] Allow ArrayInitLoopExpr and OpaqueValueExpr in trivial expressions

[rniwa]

Allow VisitArrayInitLoopExpr, VisitArrayInitIndexExpr, and VisitOpaqueValueExpr in trivial functions and statements.

[llvmbot]

@llvm/pr-subscribers-clang-static-analyzer-1

@llvm/pr-subscribers-clang

Author: Ryosuke Niwa (rniwa)

Changes

Allow VisitArrayInitLoopExpr, VisitArrayInitIndexExpr, and VisitOpaqueValueExpr in trivial functions and statements.

---

Full diff: https://github.com/llvm/llvm-project/pull/127182.diff

2 Files Affected:

• (modified) clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp (+12)
• (added) clang/test/Analysis/Checkers/WebKit/call-args-loop-init-opaque-value.cpp (+47)

diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
index d40b4b4dbb560..edfe72c62b2c8 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
@@ -589,6 +589,18 @@ class TrivialFunctionAnalysisVisitor
     return Visit(BTE->getSubExpr());
   }
 
+  bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *AILE) {
+    return Visit(AILE->getCommonExpr()) && Visit(AILE->getSubExpr());
+  }
+
+  bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *AIIE) {
+    return true; // The current array index in VisitArrayInitLoopExpr is always trivial.
+  }
+
+  bool VisitOpaqueValueExpr(const OpaqueValueExpr *OVE) {
+    return Visit(OVE->getSourceExpr());
+  }
+
   bool VisitExprWithCleanups(const ExprWithCleanups *EWC) {
     return Visit(EWC->getSubExpr());
   }
diff --git a/clang/test/Analysis/Checkers/WebKit/call-args-loop-init-opaque-value.cpp b/clang/test/Analysis/Checkers/WebKit/call-args-loop-init-opaque-value.cpp
new file mode 100644
index 0000000000000..69987c600eeb5
--- /dev/null
+++ b/clang/test/Analysis/Checkers/WebKit/call-args-loop-init-opaque-value.cpp
@@ -0,0 +1,47 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=alpha.webkit.UncountedCallArgsChecker -verify %s
+// expected-no-diagnostics
+
+typedef unsigned long size_t;
+template<typename T, size_t N>
+struct Obj {
+    constexpr static size_t Size = N;
+
+    constexpr T& operator[](size_t i) { return components[i]; }
+    constexpr const T& operator[](size_t i) const { return components[i]; }
+
+    constexpr size_t size() const { return Size; }
+
+    T components[N];
+};
+
+template<typename T, size_t N>
+constexpr bool operator==(const Obj<T, N>& a, const Obj<T, N>& b)
+{
+    for (size_t i = 0; i < N; ++i) {
+        if (a[i] == b[i])
+            continue;
+        return false;
+    }
+
+    return true;
+}
+
+class Component {
+public:
+    void ref() const;
+    void deref() const;
+
+    Obj<float, 4> unresolvedComponents() const { return m_components; }
+
+    bool isEqual(const Component& other) const {
+        return unresolvedComponents() == other.unresolvedComponents();
+    }
+
+private:
+    Obj<float, 4> m_components;
+};
+
+Component* provide();
+bool someFunction(Component* other) {
+    return provide()->isEqual(*other);
+}

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[t-rasmud]

I have a small nit about tests. Otherwise, LGTM.

[t-rasmud]

Do we need to test these expressions in non-trivial expressions? Or do such tests already exist?

[rniwa]

We have tests for non-trivial expressions: clang/test/Analysis/Checkers/WebKit/uncounted-obj-arg.cpp. I guess we can add a test case here for non-trivial case as well.

[rniwa]

Added a non-trivial test case.

[rniwa]

Thanks for the review!