[Analyzer] No longer crash with VLA operands to unary type traits #154738
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…vm#151719) sizeof was handled correctly, but __datasizeof and _Countof were not. Fixes llvm#151711 (cherry picked from commit 1732748 with adjustments) Dropping the ReleaseNotes part of the original patch.
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@llvm/pr-subscribers-clang @llvm/pr-subscribers-clang-static-analyzer-1 Author: Balazs Benics (steakhal) Changessizeof was handled correctly, but __datasizeof and _Countof were not. Fixes #151711 (cherry picked from commit 1732748 with adjustments) The Static Analyzer release notes section will mention this patch in #154600 Full diff: https://github.com/llvm/llvm-project/pull/154738.diff 2 Files Affected:
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
index fa8e669b6bb2f..ab29f86cec326 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -916,7 +916,8 @@ VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
QualType T = Ex->getTypeOfArgument();
for (ExplodedNode *N : CheckedSet) {
- if (Ex->getKind() == UETT_SizeOf) {
+ if (Ex->getKind() == UETT_SizeOf || Ex->getKind() == UETT_DataSizeOf ||
+ Ex->getKind() == UETT_CountOf) {
if (!T->isIncompleteType() && !T->isConstantSizeType()) {
assert(T->isVariableArrayType() && "Unknown non-constant-sized type.");
diff --git a/clang/test/Analysis/engine/gh151711.cpp b/clang/test/Analysis/engine/gh151711.cpp
new file mode 100644
index 0000000000000..a9950a7a3b9d0
--- /dev/null
+++ b/clang/test/Analysis/engine/gh151711.cpp
@@ -0,0 +1,18 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -verify %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -verify -x c %s
+
+void clang_analyzer_dump(int);
+
+// Ensure that VLA types are correctly handled by unary type traits in the
+// expression engine. Previously, __datasizeof and _Countof both caused failed
+// assertions.
+void gh151711(int i) {
+ clang_analyzer_dump(sizeof(int[i++])); // expected-warning {{Unknown}}
+#ifdef __cplusplus
+ // __datasizeof is only available in C++.
+ clang_analyzer_dump(__datasizeof(int[i++])); // expected-warning {{Unknown}}
+#else
+ // _Countof is only available in C.
+ clang_analyzer_dump(_Countof(int[i++])); // expected-warning {{Unknown}}
+#endif
+}
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@Xazax-hun Please have a look. |
Xazax-hun
approved these changes
Aug 27, 2025
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sizeof was handled correctly, but __datasizeof and _Countof were not.
Fixes #151711
(cherry picked from commit 1732748 with adjustments)
Dropping the ReleaseNotes part of the original patch.
The Static Analyzer release notes section will mention this patch in #154600