NoQ created this revision.
NoQ added reviewers: dcoughlin, xazax.hun, a.sidorin, george.karpenkov, szepet,
rnkovacs, baloghadamsoftware.
Herald added a subscriber: cfe-commits.
A follow-up to https://reviews.llvm.org/D47496.
This would warn the developer on the very common bug that consists in writing,
eg., `State->set<Trait>(Key, Value)` instead of `State = State->set<Trait>(Key,
Value)`. Because in the first snippet the updated `State` object is discarded
while the original object remains unchanged (because it's, well, immutable),
which isn't what you ever want to do.
For now no such bugs were found in the analyzer, but i made these mistakes
myself knowingly and i see many such bugs during code review.
Repository:
rC Clang
https://reviews.llvm.org/D47499
Files:
include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
Index: include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
@@ -177,38 +177,38 @@
///
/// This returns a new state with the added constraint on \p cond.
/// If no new state is feasible, NULL is returned.
- ProgramStateRef assume(DefinedOrUnknownSVal cond, bool assumption) const;
+ LLVM_NODISCARD ProgramStateRef assume(DefinedOrUnknownSVal cond,
+ bool assumption) const;
/// Assumes both "true" and "false" for \p cond, and returns both
/// corresponding states (respectively).
///
/// This is more efficient than calling assume() twice. Note that one (but not
/// both) of the returned states may be NULL.
- std::pair<ProgramStateRef, ProgramStateRef>
+ LLVM_NODISCARD std::pair<ProgramStateRef, ProgramStateRef>
assume(DefinedOrUnknownSVal cond) const;
- ProgramStateRef assumeInBound(DefinedOrUnknownSVal idx,
- DefinedOrUnknownSVal upperBound,
- bool assumption,
- QualType IndexType = QualType()) const;
+ LLVM_NODISCARD ProgramStateRef
+ assumeInBound(DefinedOrUnknownSVal idx, DefinedOrUnknownSVal upperBound,
+ bool assumption, QualType IndexType = QualType()) const;
/// Assumes that the value of \p Val is bounded with [\p From; \p To]
/// (if \p assumption is "true") or it is fully out of this range
/// (if \p assumption is "false").
///
/// This returns a new state with the added constraint on \p cond.
/// If no new state is feasible, NULL is returned.
- ProgramStateRef assumeInclusiveRange(DefinedOrUnknownSVal Val,
- const llvm::APSInt &From,
- const llvm::APSInt &To,
- bool assumption) const;
+ LLVM_NODISCARD ProgramStateRef assumeInclusiveRange(DefinedOrUnknownSVal Val,
+ const llvm::APSInt &From,
+ const llvm::APSInt &To,
+ bool assumption) const;
/// Assumes given range both "true" and "false" for \p Val, and returns both
/// corresponding states (respectively).
///
/// This is more efficient than calling assume() twice. Note that one (but not
/// both) of the returned states may be NULL.
- std::pair<ProgramStateRef, ProgramStateRef>
+ LLVM_NODISCARD std::pair<ProgramStateRef, ProgramStateRef>
assumeInclusiveRange(DefinedOrUnknownSVal Val, const llvm::APSInt &From,
const llvm::APSInt &To) const;
@@ -232,30 +232,32 @@
/// Create a new state by binding the value 'V' to the statement 'S' in the
/// state's environment.
- ProgramStateRef BindExpr(const Stmt *S, const LocationContext *LCtx,
- SVal V, bool Invalidate = true) const;
+ LLVM_NODISCARD ProgramStateRef BindExpr(const Stmt *S,
+ const LocationContext *LCtx, SVal V,
+ bool Invalidate = true) const;
- ProgramStateRef bindLoc(Loc location,
- SVal V,
- const LocationContext *LCtx,
- bool notifyChanges = true) const;
+ LLVM_NODISCARD ProgramStateRef bindLoc(Loc location, SVal V,
+ const LocationContext *LCtx,
+ bool notifyChanges = true) const;
- ProgramStateRef bindLoc(SVal location, SVal V, const LocationContext *LCtx) const;
+ LLVM_NODISCARD ProgramStateRef bindLoc(SVal location, SVal V,
+ const LocationContext *LCtx) const;
/// Initializes the region of memory represented by \p loc with an initial
/// value. Once initialized, all values loaded from any sub-regions of that
/// region will be equal to \p V, unless overwritten later by the program.
/// This method should not be used on regions that are already initialized.
/// If you need to indicate that memory contents have suddenly become unknown
/// within a certain region of memory, consider invalidateRegions().
- ProgramStateRef bindDefaultInitial(SVal loc, SVal V,
- const LocationContext *LCtx) const;
+ LLVM_NODISCARD ProgramStateRef
+ bindDefaultInitial(SVal loc, SVal V, const LocationContext *LCtx) const;
/// Performs C++ zero-initialization procedure on the region of memory
/// represented by \p loc.
- ProgramStateRef bindDefaultZero(SVal loc, const LocationContext *LCtx) const;
+ LLVM_NODISCARD ProgramStateRef
+ bindDefaultZero(SVal loc, const LocationContext *LCtx) const;
- ProgramStateRef killBinding(Loc LV) const;
+ LLVM_NODISCARD ProgramStateRef killBinding(Loc LV) const;
/// Returns the state with bindings for the given regions
/// cleared from the store.
@@ -275,24 +277,24 @@
/// the call and should be considered directly invalidated.
/// \param ITraits information about special handling for a particular
/// region/symbol.
- ProgramStateRef
+ LLVM_NODISCARD ProgramStateRef
invalidateRegions(ArrayRef<const MemRegion *> Regions, const Expr *E,
unsigned BlockCount, const LocationContext *LCtx,
bool CausesPointerEscape, InvalidatedSymbols *IS = nullptr,
const CallEvent *Call = nullptr,
RegionAndSymbolInvalidationTraits *ITraits = nullptr) const;
- ProgramStateRef
+ LLVM_NODISCARD ProgramStateRef
invalidateRegions(ArrayRef<SVal> Regions, const Expr *E,
unsigned BlockCount, const LocationContext *LCtx,
bool CausesPointerEscape, InvalidatedSymbols *IS = nullptr,
const CallEvent *Call = nullptr,
RegionAndSymbolInvalidationTraits *ITraits = nullptr) const;
/// enterStackFrame - Returns the state for entry to the given stack frame,
/// preserving the current state.
- ProgramStateRef enterStackFrame(const CallEvent &Call,
- const StackFrameContext *CalleeCtx) const;
+ LLVM_NODISCARD ProgramStateRef enterStackFrame(
+ const CallEvent &Call, const StackFrameContext *CalleeCtx) const;
/// Get the lvalue for a base class object reference.
Loc getLValue(const CXXBaseSpecifier &BaseSpec, const SubRegion *Super) const;
@@ -370,27 +372,29 @@
const MemRegion * const *end) const;
/// Create a new state in which the statement is marked as tainted.
- ProgramStateRef addTaint(const Stmt *S, const LocationContext *LCtx,
- TaintTagType Kind = TaintTagGeneric) const;
+ LLVM_NODISCARD ProgramStateRef
+ addTaint(const Stmt *S, const LocationContext *LCtx,
+ TaintTagType Kind = TaintTagGeneric) const;
/// Create a new state in which the value is marked as tainted.
- ProgramStateRef addTaint(SVal V, TaintTagType Kind = TaintTagGeneric) const;
+ LLVM_NODISCARD ProgramStateRef
+ addTaint(SVal V, TaintTagType Kind = TaintTagGeneric) const;
/// Create a new state in which the symbol is marked as tainted.
- ProgramStateRef addTaint(SymbolRef S,
+ LLVM_NODISCARD ProgramStateRef addTaint(SymbolRef S,
TaintTagType Kind = TaintTagGeneric) const;
/// Create a new state in which the region symbol is marked as tainted.
- ProgramStateRef addTaint(const MemRegion *R,
- TaintTagType Kind = TaintTagGeneric) const;
+ LLVM_NODISCARD ProgramStateRef
+ addTaint(const MemRegion *R, TaintTagType Kind = TaintTagGeneric) const;
/// Create a new state in a which a sub-region of a given symbol is tainted.
/// This might be necessary when referring to regions that can not have an
/// individual symbol, e.g. if they are represented by the default binding of
/// a LazyCompoundVal.
- ProgramStateRef addPartialTaint(SymbolRef ParentSym,
- const SubRegion *SubRegion,
- TaintTagType Kind = TaintTagGeneric) const;
+ LLVM_NODISCARD ProgramStateRef
+ addPartialTaint(SymbolRef ParentSym, const SubRegion *SubRegion,
+ TaintTagType Kind = TaintTagGeneric) const;
/// Check if the statement is tainted in the current state.
bool isTainted(const Stmt *S, const LocationContext *LCtx,
@@ -405,8 +409,9 @@
void *const* FindGDM(void *K) const;
- template<typename T>
- ProgramStateRef add(typename ProgramStateTrait<T>::key_type K) const;
+ template <typename T>
+ LLVM_NODISCARD ProgramStateRef
+ add(typename ProgramStateTrait<T>::key_type K) const;
template <typename T>
typename ProgramStateTrait<T>::data_type
@@ -424,27 +429,31 @@
template <typename T>
typename ProgramStateTrait<T>::context_type get_context() const;
+ template <typename T>
+ LLVM_NODISCARD ProgramStateRef
+ remove(typename ProgramStateTrait<T>::key_type K) const;
- template<typename T>
- ProgramStateRef remove(typename ProgramStateTrait<T>::key_type K) const;
-
- template<typename T>
- ProgramStateRef remove(typename ProgramStateTrait<T>::key_type K,
- typename ProgramStateTrait<T>::context_type C) const;
template <typename T>
- ProgramStateRef remove() const;
+ LLVM_NODISCARD ProgramStateRef
+ remove(typename ProgramStateTrait<T>::key_type K,
+ typename ProgramStateTrait<T>::context_type C) const;
- template<typename T>
- ProgramStateRef set(typename ProgramStateTrait<T>::data_type D) const;
+ template <typename T> LLVM_NODISCARD ProgramStateRef remove() const;
- template<typename T>
- ProgramStateRef set(typename ProgramStateTrait<T>::key_type K,
- typename ProgramStateTrait<T>::value_type E) const;
+ template <typename T>
+ LLVM_NODISCARD ProgramStateRef
+ set(typename ProgramStateTrait<T>::data_type D) const;
- template<typename T>
- ProgramStateRef set(typename ProgramStateTrait<T>::key_type K,
- typename ProgramStateTrait<T>::value_type E,
- typename ProgramStateTrait<T>::context_type C) const;
+ template <typename T>
+ LLVM_NODISCARD ProgramStateRef
+ set(typename ProgramStateTrait<T>::key_type K,
+ typename ProgramStateTrait<T>::value_type E) const;
+
+ template <typename T>
+ LLVM_NODISCARD ProgramStateRef
+ set(typename ProgramStateTrait<T>::key_type K,
+ typename ProgramStateTrait<T>::value_type E,
+ typename ProgramStateTrait<T>::context_type C) const;
template<typename T>
bool contains(typename ProgramStateTrait<T>::key_type key) const {
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