[clang][analyzer] Fix a nullptr dereference when -ftime-trace is used#139820
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[clang][analyzer] Fix a nullptr dereference when -ftime-trace is used#139820
-ftime-trace is used#139820Conversation
Fixes llvm#139779. The bug was introduced in llvm#137355 in `SymbolConjured::getStmt`, when trying to obtain a statement for a CFG initializer without an initializer. This commit adds a null check before access.
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@llvm/pr-subscribers-clang-static-analyzer-1 @llvm/pr-subscribers-clang Author: Fangyi Zhou (fangyi-zhou) ChangesFixes #139779. The bug was introduced in #137355 in Full diff: https://github.com/llvm/llvm-project/pull/139820.diff 2 Files Affected:
diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h
index 9e7c98fdded17..00159971fd7b5 100644
--- a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h
+++ b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h
@@ -103,6 +103,8 @@ class SymbolConjured : public SymbolData {
const Stmt *getStmt() const {
switch (Elem->getKind()) {
case CFGElement::Initializer:
+ if (Elem->castAs<CFGInitializer>().getInitializer() == nullptr)
+ return nullptr;
return Elem->castAs<CFGInitializer>().getInitializer()->getInit();
case CFGElement::ScopeBegin:
return Elem->castAs<CFGScopeBegin>().getTriggerStmt();
diff --git a/clang/test/Analysis/ftime-trace-no-init.cpp b/clang/test/Analysis/ftime-trace-no-init.cpp
new file mode 100644
index 0000000000000..db62aa8a56ed7
--- /dev/null
+++ b/clang/test/Analysis/ftime-trace-no-init.cpp
@@ -0,0 +1,5 @@
+// RUN: %clang --analyze %s -ftime-trace -Xclang -verify
+// expected-no-diagnostics
+
+// GitHub issue 139779
+struct {} a; // no-crash
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AaronBallman
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Generally LGTM but a suggestion for a perhaps more clear way to do it
clang/include/clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h
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steakhal
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May 14, 2025
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steakhal
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I can only agree with Aaron. It looks nice.
Thank you!
clang/include/clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h
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This seems to cause asan test failures in buildbot, I'll create a PR to revert. |
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…-ftime-trace` is used" (#139936) Reverts llvm/llvm-project#139820 Reverting due to buildbot failures in asan
steakhal
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… (Reland) (#139980) Fixes #139779. The bug was introduced in #137355 in `SymbolConjured::getStmt`, when trying to obtain a statement for a CFG initializer without an initializer. This commit adds a null check before access. Previous PR #139820, Revert #139936 Additional notes since previous PR: When conjuring a symbol, sometimes there is no valid CFG element, e.g. in the file causing the crash, there is no element at all in the CFG. In these cases, the CFG element reference in the expression engine will be invalid. As a consequence, there needs to be extra checks to ensure the validity of the CFG element reference.
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Fixes #139779.
The bug was introduced in #137355 in
SymbolConjured::getStmt, when trying to obtain a statement for a CFG initializer without an initializer. This commit adds a null check before access.