xazax.hun created this revision.
xazax.hun added reviewers: NoQ, Szelethus, baloghadamsoftware, dcoughlin,
haowei.
xazax.hun added a project: clang.
Herald added subscribers: Charusso, gamesh411, dkrupp, donat.nagy,
mikhail.ramalho, a.sidorin, rnkovacs, szepet.
xazax.hun added a comment.
So some of the questions that came to my mind:
1. Should this be exposed to the checkers?
2. Where should we actually have this trait registered? ProgramState?
ExprEngine? Both of them need access, and due to layering I feel like it cannot
be in ExprEngine but I might be wrong.
This is working progress but I wanted to share early to discuss the direction.
This looks relatively painless so far, but note that the locals are not cleaned
up from the state just yet.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D71152
Files:
clang/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
clang/lib/StaticAnalyzer/Core/ProgramState.cpp
clang/test/Analysis/symbol-escape.cpp
Index: clang/test/Analysis/symbol-escape.cpp
===================================================================
--- clang/test/Analysis/symbol-escape.cpp
+++ clang/test/Analysis/symbol-escape.cpp
@@ -31,3 +31,13 @@
return Baz;
}
+void save_ptr(int **);
+void delete_saved();
+
+void store_to_escaped_region() {
+ int *p;
+ save_ptr(&p);
+ p = new int;
+ delete_saved();
+} // no-warning:
+
Index: clang/lib/StaticAnalyzer/Core/ProgramState.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ProgramState.cpp
+++ clang/lib/StaticAnalyzer/Core/ProgramState.cpp
@@ -16,6 +16,7 @@
#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/DynamicType.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h"
#include "llvm/Support/raw_ostream.h"
@@ -41,7 +42,23 @@
Mgr.freeStates.push_back(s);
}
}
-}}
+} // namespace ento
+} // namespace clang
+
+namespace {
+struct EscapedLocals{};
+} // namespace
+
+template <>
+struct ProgramStateTrait<EscapedLocals> :
+ public ProgramStatePartialTrait<llvm::ImmutableSet<const MemRegion *>> {
+ static void *GDMIndex();
+};
+
+void *ProgramStateTrait<EscapedLocals>::GDMIndex() {
+ static int index = 0;
+ return &index;
+}
ProgramState::ProgramState(ProgramStateManager *mgr, const Environment& env,
StoreRef st, GenericDataMap gdm)
@@ -209,6 +226,12 @@
ProgramStateRef newState = makeWithStore(newStore);
if (CausedByPointerEscape) {
+ for (const MemRegion *R : Invalidated) {
+ if (!R->hasStackStorage())
+ continue;
+ newState = newState->add<EscapedLocals>(R);
+ }
+
newState = Eng.notifyCheckersOfPointerEscape(newState, IS,
TopLevelInvalidated,
Call,
@@ -642,3 +665,7 @@
}
return true;
}
+
+bool ProgramState::isEscapedLocal(const MemRegion *R) const {
+ return this->contains<EscapedLocals>(R);
+}
Index: clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -2680,7 +2680,8 @@
// A value escapes in four possible cases:
// (1) We are binding to something that is not a memory region.
-// (2) We are binding to a MemRegion that does not have stack storage.
+// (2) We are binding to a MemRegion that does not have stack storage
+// or the stack storage is escaped.
// (3) We are binding to a top-level parameter region with a non-trivial
// destructor. We won't see the destructor during analysis, but it's there.
// (4) We are binding to a MemRegion with stack storage that the store
@@ -2691,7 +2692,7 @@
// Cases (1) and (2).
const MemRegion *MR = Loc.getAsRegion();
- if (!MR || !MR->hasStackStorage())
+ if (!MR || !MR->hasStackStorage() || State->isEscapedLocal(MR))
return escapeValue(State, Val, PSK_EscapeOnBind);
// Case (3).
Index: clang/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
===================================================================
--- clang/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
+++ clang/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
@@ -345,6 +345,9 @@
/// a value of such type.
SVal getSValAsScalarOrLoc(const MemRegion *R) const;
+ /// TODO
+ bool isEscapedLocal(const MemRegion *R) const;
+
using region_iterator = const MemRegion **;
/// Visits the symbols reachable from the given SVal using the provided
@@ -872,8 +875,8 @@
bool scan(const SymExpr *sym);
};
-} // end ento namespace
+} // namespace ento
-} // end clang namespace
+} // namespace clang
#endif
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