//===- Consumed.h -----------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// A intra-procedural analysis for checking consumed properties. This is based,
// in part, on research on linear types.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_CONSUMED_H
#define LLVM_CLANG_ANALYSIS_ANALYSES_CONSUMED_H
#include "clang/Analysis/Analyses/PostOrderCFGView.h"
#include "clang/Analysis/CFG.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include <list>
#include <memory>
#include <utility>
#include <vector>
namespace clang {
class AnalysisDeclContext;
class CXXBindTemporaryExpr;
class FunctionDecl;
class PostOrderCFGView;
class Stmt;
class VarDecl;
namespace consumed {
class ConsumedStmtVisitor;
enum ConsumedState {
// No state information for the given variable.
CS_None,
CS_Unknown,
CS_Unconsumed,
CS_Consumed
};
using OptionalNotes = SmallVector<PartialDiagnosticAt, 1>;
using DelayedDiag = std::pair<PartialDiagnosticAt, OptionalNotes>;
using DiagList = std::list<DelayedDiag>;
class ConsumedWarningsHandlerBase {
public:
virtual ~ConsumedWarningsHandlerBase();
/// Emit the warnings and notes left by the analysis.
virtual void emitDiagnostics() {}
/// Warn that a variable's state doesn't match at the entry and exit
/// of a loop.
///
/// \param Loc -- The location of the end of the loop.
///
/// \param VariableName -- The name of the variable that has a mismatched
/// state.
virtual void warnLoopStateMismatch(SourceLocation Loc,
StringRef VariableName) {}
/// Warn about parameter typestate mismatches upon return.
///
/// \param Loc -- The SourceLocation of the return statement.
///
/// \param ExpectedState -- The state the return value was expected to be
/// in.
///
/// \param ObservedState -- The state the return value was observed to be
/// in.
virtual void warnParamReturnTypestateMismatch(SourceLocation Loc,
StringRef VariableName,
StringRef ExpectedState,
StringRef ObservedState) {}
// FIXME: Add documentation.
virtual void warnParamTypestateMismatch(SourceLocation LOC,
StringRef ExpectedState,
StringRef ObservedState) {}
// FIXME: This can be removed when the attr propagation fix for templated
// classes lands.
/// Warn about return typestates set for unconsumable types.
///
/// \param Loc -- The location of the attributes.
///
/// \param TypeName -- The name of the unconsumable type.
virtual void warnReturnTypestateForUnconsumableType(SourceLocation Loc,
StringRef TypeName) {}
/// Warn about return typestate mismatches.
///
/// \param Loc -- The SourceLocation of the return statement.
///
/// \param ExpectedState -- The state the return value was expected to be
/// in.
///
/// \param ObservedState -- The state the return value was observed to be
/// in.
virtual void warnReturnTypestateMismatch(SourceLocation Loc,
StringRef ExpectedState,
StringRef ObservedState) {}
/// Warn about use-while-consumed errors.
/// \param MethodName -- The name of the method that was incorrectly
/// invoked.
///
/// \param State -- The state the object was used in.
///
/// \param Loc -- The SourceLocation of the method invocation.
virtual void warnUseOfTempInInvalidState(StringRef MethodName,
StringRef State,
SourceLocation Loc) {}
/// Warn about use-while-consumed errors.
/// \param MethodName -- The name of the method that was incorrectly
/// invoked.
///
/// \param State -- The state the object was used in.
///
/// \param VariableName -- The name of the variable that holds the unique
/// value.
///
/// \param Loc -- The SourceLocation of the method invocation.
virtual void warnUseInInvalidState(StringRef MethodName,
StringRef VariableName,
StringRef State,
SourceLocation Loc) {}
};
class ConsumedStateMap {
using VarMapType = llvm::DenseMap<const VarDecl *, ConsumedState>;
using TmpMapType =
llvm::DenseMap<const CXXBindTemporaryExpr *, ConsumedState>;
protected:
bool Reachable = true;
const Stmt *From = nullptr;
VarMapType VarMap;
TmpMapType TmpMap;
public:
ConsumedStateMap() = default;
ConsumedStateMap(const ConsumedStateMap &Other)
: Reachable(Other.Reachable), From(Other.From), VarMap(Other.VarMap) {}
/// Warn if any of the parameters being tracked are not in the state
/// they were declared to be in upon return from a function.
void checkParamsForReturnTypestate(SourceLocation BlameLoc,
ConsumedWarningsHandlerBase &WarningsHandler) const;
/// Clear the TmpMap.
void clearTemporaries();
/// Get the consumed state of a given variable.
ConsumedState getState(const VarDecl *Var) const;
/// Get the consumed state of a given temporary value.
ConsumedState getState(const CXXBindTemporaryExpr *Tmp) const;
/// Merge this state map with another map.
void intersect(const ConsumedStateMap &Other);
void intersectAtLoopHead(const CFGBlock *LoopHead, const CFGBlock *LoopBack,
const ConsumedStateMap *LoopBackStates,
ConsumedWarningsHandlerBase &WarningsHandler);
/// Return true if this block is reachable.
bool isReachable() const { return Reachable; }
/// Mark the block as unreachable.
void markUnreachable();
/// Set the source for a decision about the branching of states.
/// \param Source -- The statement that was the origin of a branching
/// decision.
void setSource(const Stmt *Source) { this->From = Source; }
/// Set the consumed state of a given variable.
void setState(const VarDecl *Var, ConsumedState State);
/// Set the consumed state of a given temporary value.
void setState(const CXXBindTemporaryExpr *Tmp, ConsumedState State);
/// Remove the temporary value from our state map.
void remove(const CXXBindTemporaryExpr *Tmp);
/// Tests to see if there is a mismatch in the states stored in two
/// maps.
///
/// \param Other -- The second map to compare against.
bool operator!=(const ConsumedStateMap *Other) const;
};
class ConsumedBlockInfo {
std::vector<std::unique_ptr<ConsumedStateMap>> StateMapsArray;
std::vector<unsigned int> VisitOrder;
public:
ConsumedBlockInfo() = default;
ConsumedBlockInfo(unsigned int NumBlocks, PostOrderCFGView *SortedGraph)
: StateMapsArray(NumBlocks), VisitOrder(NumBlocks, 0) {
unsigned int VisitOrderCounter = 0;
for (const auto BI : *SortedGraph)
VisitOrder[BI->getBlockID()] = VisitOrderCounter++;
}
bool allBackEdgesVisited(const CFGBlock *CurrBlock,
const CFGBlock *TargetBlock);
void addInfo(const CFGBlock *Block, ConsumedStateMap *StateMap,
std::unique_ptr<ConsumedStateMap> &OwnedStateMap);
void addInfo(const CFGBlock *Block,
std::unique_ptr<ConsumedStateMap> StateMap);
ConsumedStateMap* borrowInfo(const CFGBlock *Block);
void discardInfo(const CFGBlock *Block);
std::unique_ptr<ConsumedStateMap> getInfo(const CFGBlock *Block);
bool isBackEdge(const CFGBlock *From, const CFGBlock *To);
bool isBackEdgeTarget(const CFGBlock *Block);
};
/// A class that handles the analysis of uniqueness violations.
class ConsumedAnalyzer {
ConsumedBlockInfo BlockInfo;
std::unique_ptr<ConsumedStateMap> CurrStates;
ConsumedState ExpectedReturnState;
void determineExpectedReturnState(AnalysisDeclContext &AC,
const FunctionDecl *D);
bool splitState(const CFGBlock *CurrBlock,
const ConsumedStmtVisitor &Visitor);
public:
ConsumedWarningsHandlerBase &WarningsHandler;
ConsumedAnalyzer(ConsumedWarningsHandlerBase &WarningsHandler)
: WarningsHandler(WarningsHandler) {}
ConsumedState getExpectedReturnState() const { return ExpectedReturnState; }
/// Check a function's CFG for consumed violations.
///
/// We traverse the blocks in the CFG, keeping track of the state of each
/// value who's type has uniquness annotations. If methods are invoked in
/// the wrong state a warning is issued. Each block in the CFG is traversed
/// exactly once.
void run(AnalysisDeclContext &AC);
};
} // namespace consumed
} // namespace clang
#endif // LLVM_CLANG_ANALYSIS_ANALYSES_CONSUMED_H