[Analyzer] No longer crash with VLA operands to unary type traits #151719
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sizeof was handled correctly, but __datasizeof and _Countof were not. Fixes llvm#151711
AaronBallman
added
clang
|
@llvm/pr-subscribers-clang-static-analyzer-1 Author: Aaron Ballman (AaronBallman) Changessizeof was handled correctly, but __datasizeof and _Countof were not. Fixes #151711 Full diff: https://github.com/llvm/llvm-project/pull/151719.diff 3 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 4a2edae7509de..69b5605df52d6 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -241,6 +241,8 @@ Static Analyzer
---------------
- The Clang Static Analyzer now handles parenthesized initialization.
(#GH148875)
+- ``__datasizeof`` (C++) and ``_Countof`` (C) no longer cause a failed assertion
+ when given an operand of VLA type. (#GH151711)
New features
^^^^^^^^^^^^
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
index f1a25a750dd0d..4ddf8fd5b4b0f 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -868,7 +868,8 @@ 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..8d8488e3bc1f8
--- /dev/null
+++ b/clang/test/Analysis/engine/gh151711.cpp
@@ -0,0 +1,18 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core -verify %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=core -verify -x c -std=c2y %s
+// expected-no-diagnostics
+
+// 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) {
+ (void)sizeof(int[i++]);
+
+#ifdef __cplusplus
+ // __datasizeof is only available in C++.
+ (void)__datasizeof(int[i++]);
+#else
+ // _Countof is only available in C.
+ (void)_Countof(int[i++]);
+#endif
+}
|
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@llvm/pr-subscribers-clang Author: Aaron Ballman (AaronBallman) Changessizeof was handled correctly, but __datasizeof and _Countof were not. Fixes #151711 Full diff: https://github.com/llvm/llvm-project/pull/151719.diff 3 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 4a2edae7509de..69b5605df52d6 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -241,6 +241,8 @@ Static Analyzer
---------------
- The Clang Static Analyzer now handles parenthesized initialization.
(#GH148875)
+- ``__datasizeof`` (C++) and ``_Countof`` (C) no longer cause a failed assertion
+ when given an operand of VLA type. (#GH151711)
New features
^^^^^^^^^^^^
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
index f1a25a750dd0d..4ddf8fd5b4b0f 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -868,7 +868,8 @@ 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..8d8488e3bc1f8
--- /dev/null
+++ b/clang/test/Analysis/engine/gh151711.cpp
@@ -0,0 +1,18 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core -verify %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=core -verify -x c -std=c2y %s
+// expected-no-diagnostics
+
+// 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) {
+ (void)sizeof(int[i++]);
+
+#ifdef __cplusplus
+ // __datasizeof is only available in C++.
+ (void)__datasizeof(int[i++]);
+#else
+ // _Countof is only available in C.
+ (void)_Countof(int[i++]);
+#endif
+}
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Hold on, the issue you fixed here was only opened like 30 minutes ago, how did you patch this in just 10 minutes? |
I happened to triage the issue and went "I wonder what's going on?" then saw what was happening and realized "I just had to do this dance for |
steakhal
approved these changes
Aug 1, 2025
Xazax-hun
approved these changes
Aug 1, 2025
krishna2803
pushed a commit
to krishna2803/llvm-project
that referenced
this pull request
Aug 12, 2025
…vm#151719) sizeof was handled correctly, but __datasizeof and _Countof were not. Fixes llvm#151711
|
/cherry-pick 1732748 |
Error: Command failed due to missing milestone. |
|
/cherry-pick 1732748 |
|
Failed to cherry-pick: 1732748 https://github.com/llvm/llvm-project/actions/runs/17107761517 Please manually backport the fix and push it to your github fork. Once this is done, please create a pull request |
steakhal
pushed a commit
to steakhal/llvm-project
that referenced
this pull request
Aug 21, 2025
…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.
|
The clang-21 backport PR is #154738. |
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sizeof was handled correctly, but __datasizeof and _Countof were not.
Fixes #151711