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llvm-project/clang/lib/Analysis/Consumed.cpp

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//===- Consumed.cpp -------------------------------------------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/Analyses/Consumed.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/AST/Type.h"
#include "clang/Analysis/Analyses/PostOrderCFGView.h"
#include "clang/Analysis/AnalysisDeclContext.h"
#include "clang/Analysis/CFG.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/OperatorKinds.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include <cassert>
#include <memory>
#include <utility>
// TODO: Adjust states of args to constructors in the same way that arguments to
// function calls are handled.
// TODO: Use information from tests in for- and while-loop conditional.
// TODO: Add notes about the actual and expected state for
// TODO: Correctly identify unreachable blocks when chaining boolean operators.
// TODO: Adjust the parser and AttributesList class to support lists of
// identifiers.
// TODO: Warn about unreachable code.
// TODO: Switch to using a bitmap to track unreachable blocks.
// TODO: Handle variable definitions, e.g. bool valid = x.isValid();
// if (valid) ...; (Deferred)
// TODO: Take notes on state transitions to provide better warning messages.
// (Deferred)
// TODO: Test nested conditionals: A) Checking the same value multiple times,
// and 2) Checking different values. (Deferred)
using namespace clang;
using namespace consumed;
// Key method definition
ConsumedWarningsHandlerBase::~ConsumedWarningsHandlerBase() = default;
static SourceLocation getFirstStmtLoc(const CFGBlock *Block) {
// Find the source location of the first statement in the block, if the block
// is not empty.
for (const auto &B : *Block)
if (Optional<CFGStmt> CS = B.getAs<CFGStmt>())
return CS->getStmt()->getBeginLoc();
// Block is empty.
// If we have one successor, return the first statement in that block
if (Block->succ_size() == 1 && *Block->succ_begin())
return getFirstStmtLoc(*Block->succ_begin());
return {};
}
static SourceLocation getLastStmtLoc(const CFGBlock *Block) {
// Find the source location of the last statement in the block, if the block
// is not empty.
if (const Stmt *StmtNode = Block->getTerminatorStmt()) {
return StmtNode->getBeginLoc();
} else {
for (CFGBlock::const_reverse_iterator BI = Block->rbegin(),
BE = Block->rend(); BI != BE; ++BI) {
if (Optional<CFGStmt> CS = BI->getAs<CFGStmt>())
return CS->getStmt()->getBeginLoc();
}
}
// If we have one successor, return the first statement in that block
SourceLocation Loc;
if (Block->succ_size() == 1 && *Block->succ_begin())
Loc = getFirstStmtLoc(*Block->succ_begin());
if (Loc.isValid())
return Loc;
// If we have one predecessor, return the last statement in that block
if (Block->pred_size() == 1 && *Block->pred_begin())
return getLastStmtLoc(*Block->pred_begin());
return Loc;
}
static ConsumedState invertConsumedUnconsumed(ConsumedState State) {
switch (State) {
case CS_Unconsumed:
return CS_Consumed;
case CS_Consumed:
return CS_Unconsumed;
case CS_None:
return CS_None;
case CS_Unknown:
return CS_Unknown;
}
llvm_unreachable("invalid enum");
}
static bool isCallableInState(const CallableWhenAttr *CWAttr,
ConsumedState State) {
for (const auto &S : CWAttr->callableStates()) {
ConsumedState MappedAttrState = CS_None;
switch (S) {
case CallableWhenAttr::Unknown:
MappedAttrState = CS_Unknown;
break;
case CallableWhenAttr::Unconsumed:
MappedAttrState = CS_Unconsumed;
break;
case CallableWhenAttr::Consumed:
MappedAttrState = CS_Consumed;
break;
}
if (MappedAttrState == State)
return true;
}
return false;
}
static bool isConsumableType(const QualType &QT) {
if (QT->isPointerType() || QT->isReferenceType())
return false;
if (const CXXRecordDecl *RD = QT->getAsCXXRecordDecl())
return RD->hasAttr<ConsumableAttr>();
return false;
}
static bool isAutoCastType(const QualType &QT) {
if (QT->isPointerType() || QT->isReferenceType())
return false;
if (const CXXRecordDecl *RD = QT->getAsCXXRecordDecl())
return RD->hasAttr<ConsumableAutoCastAttr>();
return false;
}
static bool isSetOnReadPtrType(const QualType &QT) {
if (const CXXRecordDecl *RD = QT->getPointeeCXXRecordDecl())
return RD->hasAttr<ConsumableSetOnReadAttr>();
return false;
}
static bool isKnownState(ConsumedState State) {
switch (State) {
case CS_Unconsumed:
case CS_Consumed:
return true;
case CS_None:
case CS_Unknown:
return false;
}
llvm_unreachable("invalid enum");
}
static bool isRValueRef(QualType ParamType) {
return ParamType->isRValueReferenceType();
}
static bool isTestingFunction(const FunctionDecl *FunDecl) {
return FunDecl->hasAttr<TestTypestateAttr>();
}
static bool isPointerOrRef(QualType ParamType) {
return ParamType->isPointerType() || ParamType->isReferenceType();
}
static ConsumedState mapConsumableAttrState(const QualType QT) {
assert(isConsumableType(QT));
const ConsumableAttr *CAttr =
QT->getAsCXXRecordDecl()->getAttr<ConsumableAttr>();
switch (CAttr->getDefaultState()) {
case ConsumableAttr::Unknown:
return CS_Unknown;
case ConsumableAttr::Unconsumed:
return CS_Unconsumed;
case ConsumableAttr::Consumed:
return CS_Consumed;
}
llvm_unreachable("invalid enum");
}
static ConsumedState
mapParamTypestateAttrState(const ParamTypestateAttr *PTAttr) {
switch (PTAttr->getParamState()) {
case ParamTypestateAttr::Unknown:
return CS_Unknown;
case ParamTypestateAttr::Unconsumed:
return CS_Unconsumed;
case ParamTypestateAttr::Consumed:
return CS_Consumed;
}
llvm_unreachable("invalid_enum");
}
static ConsumedState
mapReturnTypestateAttrState(const ReturnTypestateAttr *RTSAttr) {
switch (RTSAttr->getState()) {
case ReturnTypestateAttr::Unknown:
return CS_Unknown;
case ReturnTypestateAttr::Unconsumed:
return CS_Unconsumed;
case ReturnTypestateAttr::Consumed:
return CS_Consumed;
}
llvm_unreachable("invalid enum");
}
static ConsumedState mapSetTypestateAttrState(const SetTypestateAttr *STAttr) {
switch (STAttr->getNewState()) {
case SetTypestateAttr::Unknown:
return CS_Unknown;
case SetTypestateAttr::Unconsumed:
return CS_Unconsumed;
case SetTypestateAttr::Consumed:
return CS_Consumed;
}
llvm_unreachable("invalid_enum");
}
static StringRef stateToString(ConsumedState State) {
switch (State) {
case consumed::CS_None:
return "none";
case consumed::CS_Unknown:
return "unknown";
case consumed::CS_Unconsumed:
return "unconsumed";
case consumed::CS_Consumed:
return "consumed";
}
llvm_unreachable("invalid enum");
}
static ConsumedState testsFor(const FunctionDecl *FunDecl) {
assert(isTestingFunction(FunDecl));
switch (FunDecl->getAttr<TestTypestateAttr>()->getTestState()) {
case TestTypestateAttr::Unconsumed:
return CS_Unconsumed;
case TestTypestateAttr::Consumed:
return CS_Consumed;
}
llvm_unreachable("invalid enum");
}
namespace {
struct VarTestResult {
const VarDecl *Var;
ConsumedState TestsFor;
};
} // namespace
namespace clang {
namespace consumed {
enum EffectiveOp {
EO_And,
EO_Or
};
class PropagationInfo {
enum {
IT_None,
IT_State,
IT_VarTest,
IT_BinTest,
IT_Var,
IT_Tmp
} InfoType = IT_None;
struct BinTestTy {
const BinaryOperator *Source;
EffectiveOp EOp;
VarTestResult LTest;
VarTestResult RTest;
};
union {
ConsumedState State;
VarTestResult VarTest;
const VarDecl *Var;
const CXXBindTemporaryExpr *Tmp;
BinTestTy BinTest;
};
public:
PropagationInfo() = default;
PropagationInfo(const VarTestResult &VarTest)
: InfoType(IT_VarTest), VarTest(VarTest) {}
PropagationInfo(const VarDecl *Var, ConsumedState TestsFor)
: InfoType(IT_VarTest) {
VarTest.Var = Var;
VarTest.TestsFor = TestsFor;
}
PropagationInfo(const BinaryOperator *Source, EffectiveOp EOp,
const VarTestResult &LTest, const VarTestResult &RTest)
: InfoType(IT_BinTest) {
BinTest.Source = Source;
BinTest.EOp = EOp;
BinTest.LTest = LTest;
BinTest.RTest = RTest;
}
PropagationInfo(const BinaryOperator *Source, EffectiveOp EOp,
const VarDecl *LVar, ConsumedState LTestsFor,
const VarDecl *RVar, ConsumedState RTestsFor)
: InfoType(IT_BinTest) {
BinTest.Source = Source;
BinTest.EOp = EOp;
BinTest.LTest.Var = LVar;
BinTest.LTest.TestsFor = LTestsFor;
BinTest.RTest.Var = RVar;
BinTest.RTest.TestsFor = RTestsFor;
}
PropagationInfo(ConsumedState State)
: InfoType(IT_State), State(State) {}
PropagationInfo(const VarDecl *Var) : InfoType(IT_Var), Var(Var) {}
PropagationInfo(const CXXBindTemporaryExpr *Tmp)
: InfoType(IT_Tmp), Tmp(Tmp) {}
const ConsumedState &getState() const {
assert(InfoType == IT_State);
return State;
}
const VarTestResult &getVarTest() const {
assert(InfoType == IT_VarTest);
return VarTest;
}
const VarTestResult &getLTest() const {
assert(InfoType == IT_BinTest);
return BinTest.LTest;
}
const VarTestResult &getRTest() const {
assert(InfoType == IT_BinTest);
return BinTest.RTest;
}
const VarDecl *getVar() const {
assert(InfoType == IT_Var);
return Var;
}
const CXXBindTemporaryExpr *getTmp() const {
assert(InfoType == IT_Tmp);
return Tmp;
}
ConsumedState getAsState(const ConsumedStateMap *StateMap) const {
assert(isVar() || isTmp() || isState());
if (isVar())
return StateMap->getState(Var);
else if (isTmp())
return StateMap->getState(Tmp);
else if (isState())
return State;
else
return CS_None;
}
EffectiveOp testEffectiveOp() const {
assert(InfoType == IT_BinTest);
return BinTest.EOp;
}
const BinaryOperator * testSourceNode() const {
assert(InfoType == IT_BinTest);
return BinTest.Source;
}
bool isValid() const { return InfoType != IT_None; }
bool isState() const { return InfoType == IT_State; }
bool isVarTest() const { return InfoType == IT_VarTest; }
bool isBinTest() const { return InfoType == IT_BinTest; }
bool isVar() const { return InfoType == IT_Var; }
bool isTmp() const { return InfoType == IT_Tmp; }
bool isTest() const {
return InfoType == IT_VarTest || InfoType == IT_BinTest;
}
bool isPointerToValue() const {
return InfoType == IT_Var || InfoType == IT_Tmp;
}
PropagationInfo invertTest() const {
assert(InfoType == IT_VarTest || InfoType == IT_BinTest);
if (InfoType == IT_VarTest) {
return PropagationInfo(VarTest.Var,
invertConsumedUnconsumed(VarTest.TestsFor));
} else if (InfoType == IT_BinTest) {
return PropagationInfo(BinTest.Source,
BinTest.EOp == EO_And ? EO_Or : EO_And,
BinTest.LTest.Var, invertConsumedUnconsumed(BinTest.LTest.TestsFor),
BinTest.RTest.Var, invertConsumedUnconsumed(BinTest.RTest.TestsFor));
} else {
return {};
}
}
};
} // namespace consumed
} // namespace clang
static void
setStateForVarOrTmp(ConsumedStateMap *StateMap, const PropagationInfo &PInfo,
ConsumedState State) {
assert(PInfo.isVar() || PInfo.isTmp());
if (PInfo.isVar())
StateMap->setState(PInfo.getVar(), State);
else
StateMap->setState(PInfo.getTmp(), State);
}
namespace clang {
namespace consumed {
class ConsumedStmtVisitor : public ConstStmtVisitor<ConsumedStmtVisitor> {
using MapType = llvm::DenseMap<const Stmt *, PropagationInfo>;
using PairType= std::pair<const Stmt *, PropagationInfo>;
using InfoEntry = MapType::iterator;
using ConstInfoEntry = MapType::const_iterator;
ConsumedAnalyzer &Analyzer;
ConsumedStateMap *StateMap;
MapType PropagationMap;
InfoEntry findInfo(const Expr *E) {
if (const auto Cleanups = dyn_cast<ExprWithCleanups>(E))
if (!Cleanups->cleanupsHaveSideEffects())
E = Cleanups->getSubExpr();
return PropagationMap.find(E->IgnoreParens());
}
ConstInfoEntry findInfo(const Expr *E) const {
if (const auto Cleanups = dyn_cast<ExprWithCleanups>(E))
if (!Cleanups->cleanupsHaveSideEffects())
E = Cleanups->getSubExpr();
return PropagationMap.find(E->IgnoreParens());
}
void insertInfo(const Expr *E, const PropagationInfo &PI) {
PropagationMap.insert(PairType(E->IgnoreParens(), PI));
}
void forwardInfo(const Expr *From, const Expr *To);
void copyInfo(const Expr *From, const Expr *To, ConsumedState CS);
ConsumedState getInfo(const Expr *From);
void setInfo(const Expr *To, ConsumedState NS);
void propagateReturnType(const Expr *Call, const FunctionDecl *Fun);
public:
void checkCallability(const PropagationInfo &PInfo,
const FunctionDecl *FunDecl,
SourceLocation BlameLoc);
bool handleCall(const CallExpr *Call, const Expr *ObjArg,
const FunctionDecl *FunD);
void VisitBinaryOperator(const BinaryOperator *BinOp);
void VisitCallExpr(const CallExpr *Call);
void VisitCastExpr(const CastExpr *Cast);
void VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *Temp);
void VisitCXXConstructExpr(const CXXConstructExpr *Call);
void VisitCXXMemberCallExpr(const CXXMemberCallExpr *Call);
void VisitCXXOperatorCallExpr(const CXXOperatorCallExpr *Call);
void VisitDeclRefExpr(const DeclRefExpr *DeclRef);
void VisitDeclStmt(const DeclStmt *DelcS);
void VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *Temp);
void VisitMemberExpr(const MemberExpr *MExpr);
void VisitParmVarDecl(const ParmVarDecl *Param);
void VisitReturnStmt(const ReturnStmt *Ret);
void VisitUnaryOperator(const UnaryOperator *UOp);
void VisitVarDecl(const VarDecl *Var);
ConsumedStmtVisitor(ConsumedAnalyzer &Analyzer, ConsumedStateMap *StateMap)
: Analyzer(Analyzer), StateMap(StateMap) {}
PropagationInfo getInfo(const Expr *StmtNode) const {
ConstInfoEntry Entry = findInfo(StmtNode);
if (Entry != PropagationMap.end())
return Entry->second;
else
return {};
}
void reset(ConsumedStateMap *NewStateMap) {
StateMap = NewStateMap;
}
};
} // namespace consumed
} // namespace clang
void ConsumedStmtVisitor::forwardInfo(const Expr *From, const Expr *To) {
InfoEntry Entry = findInfo(From);
if (Entry != PropagationMap.end())
insertInfo(To, Entry->second);
}
// Create a new state for To, which is initialized to the state of From.
// If NS is not CS_None, sets the state of From to NS.
void ConsumedStmtVisitor::copyInfo(const Expr *From, const Expr *To,
ConsumedState NS) {
InfoEntry Entry = findInfo(From);
if (Entry != PropagationMap.end()) {
PropagationInfo& PInfo = Entry->second;
ConsumedState CS = PInfo.getAsState(StateMap);
if (CS != CS_None)
insertInfo(To, PropagationInfo(CS));
if (NS != CS_None && PInfo.isPointerToValue())
setStateForVarOrTmp(StateMap, PInfo, NS);
}
}
// Get the ConsumedState for From
ConsumedState ConsumedStmtVisitor::getInfo(const Expr *From) {
InfoEntry Entry = findInfo(From);
if (Entry != PropagationMap.end()) {
PropagationInfo& PInfo = Entry->second;
return PInfo.getAsState(StateMap);
}
return CS_None;
}
// If we already have info for To then update it, otherwise create a new entry.
void ConsumedStmtVisitor::setInfo(const Expr *To, ConsumedState NS) {
InfoEntry Entry = findInfo(To);
if (Entry != PropagationMap.end()) {
PropagationInfo& PInfo = Entry->second;
if (PInfo.isPointerToValue())
setStateForVarOrTmp(StateMap, PInfo, NS);
} else if (NS != CS_None) {
insertInfo(To, PropagationInfo(NS));
}
}
void ConsumedStmtVisitor::checkCallability(const PropagationInfo &PInfo,
const FunctionDecl *FunDecl,
SourceLocation BlameLoc) {
assert(!PInfo.isTest());
const CallableWhenAttr *CWAttr = FunDecl->getAttr<CallableWhenAttr>();
if (!CWAttr)
return;
if (PInfo.isVar()) {
ConsumedState VarState = StateMap->getState(PInfo.getVar());
if (VarState == CS_None || isCallableInState(CWAttr, VarState))
return;
Analyzer.WarningsHandler.warnUseInInvalidState(
FunDecl->getNameAsString(), PInfo.getVar()->getNameAsString(),
stateToString(VarState), BlameLoc);
} else {
ConsumedState TmpState = PInfo.getAsState(StateMap);
if (TmpState == CS_None || isCallableInState(CWAttr, TmpState))
return;
Analyzer.WarningsHandler.warnUseOfTempInInvalidState(
FunDecl->getNameAsString(), stateToString(TmpState), BlameLoc);
}
}
// Factors out common behavior for function, method, and operator calls.
// Check parameters and set parameter state if necessary.
// Returns true if the state of ObjArg is set, or false otherwise.
bool ConsumedStmtVisitor::handleCall(const CallExpr *Call, const Expr *ObjArg,
const FunctionDecl *FunD) {
unsigned Offset = 0;
if (isa<CXXOperatorCallExpr>(Call) && isa<CXXMethodDecl>(FunD))
Offset = 1; // first argument is 'this'
// check explicit parameters
for (unsigned Index = Offset; Index < Call->getNumArgs(); ++Index) {
// Skip variable argument lists.
if (Index - Offset >= FunD->getNumParams())
break;
const ParmVarDecl *Param = FunD->getParamDecl(Index - Offset);
QualType ParamType = Param->getType();
InfoEntry Entry = findInfo(Call->getArg(Index));
if (Entry == PropagationMap.end() || Entry->second.isTest())
continue;
PropagationInfo PInfo = Entry->second;
// Check that the parameter is in the correct state.
if (ParamTypestateAttr *PTA = Param->getAttr<ParamTypestateAttr>()) {
ConsumedState ParamState = PInfo.getAsState(StateMap);
ConsumedState ExpectedState = mapParamTypestateAttrState(PTA);
if (ParamState != ExpectedState)
Analyzer.WarningsHandler.warnParamTypestateMismatch(
Call->getArg(Index)->getExprLoc(),
stateToString(ExpectedState), stateToString(ParamState));
}
if (!(Entry->second.isVar() || Entry->second.isTmp()))
continue;
// Adjust state on the caller side.
if (ReturnTypestateAttr *RT = Param->getAttr<ReturnTypestateAttr>())
setStateForVarOrTmp(StateMap, PInfo, mapReturnTypestateAttrState(RT));
else if (isRValueRef(ParamType) || isConsumableType(ParamType))
setStateForVarOrTmp(StateMap, PInfo, consumed::CS_Consumed);
else if (isPointerOrRef(ParamType) &&
(!ParamType->getPointeeType().isConstQualified() ||
isSetOnReadPtrType(ParamType)))
setStateForVarOrTmp(StateMap, PInfo, consumed::CS_Unknown);
}
if (!ObjArg)
return false;
// check implicit 'self' parameter, if present
InfoEntry Entry = findInfo(ObjArg);
if (Entry != PropagationMap.end()) {
PropagationInfo PInfo = Entry->second;
checkCallability(PInfo, FunD, Call->getExprLoc());
if (SetTypestateAttr *STA = FunD->getAttr<SetTypestateAttr>()) {
if (PInfo.isVar()) {
StateMap->setState(PInfo.getVar(), mapSetTypestateAttrState(STA));
return true;
}
else if (PInfo.isTmp()) {
StateMap->setState(PInfo.getTmp(), mapSetTypestateAttrState(STA));
return true;
}
}
else if (isTestingFunction(FunD) && PInfo.isVar()) {
PropagationMap.insert(PairType(Call,
PropagationInfo(PInfo.getVar(), testsFor(FunD))));
}
}
return false;
}
void ConsumedStmtVisitor::propagateReturnType(const Expr *Call,
const FunctionDecl *Fun) {
QualType RetType = Fun->getCallResultType();
if (RetType->isReferenceType())
RetType = RetType->getPointeeType();
if (isConsumableType(RetType)) {
ConsumedState ReturnState;
if (ReturnTypestateAttr *RTA = Fun->getAttr<ReturnTypestateAttr>())
ReturnState = mapReturnTypestateAttrState(RTA);
else
ReturnState = mapConsumableAttrState(RetType);
PropagationMap.insert(PairType(Call, PropagationInfo(ReturnState)));
}
}
void ConsumedStmtVisitor::VisitBinaryOperator(const BinaryOperator *BinOp) {
switch (BinOp->getOpcode()) {
case BO_LAnd:
case BO_LOr : {
InfoEntry LEntry = findInfo(BinOp->getLHS()),
REntry = findInfo(BinOp->getRHS());
VarTestResult LTest, RTest;
if (LEntry != PropagationMap.end() && LEntry->second.isVarTest()) {
LTest = LEntry->second.getVarTest();
} else {
LTest.Var = nullptr;
LTest.TestsFor = CS_None;
}
if (REntry != PropagationMap.end() && REntry->second.isVarTest()) {
RTest = REntry->second.getVarTest();
} else {
RTest.Var = nullptr;
RTest.TestsFor = CS_None;
}
if (!(LTest.Var == nullptr && RTest.Var == nullptr))
PropagationMap.insert(PairType(BinOp, PropagationInfo(BinOp,
static_cast<EffectiveOp>(BinOp->getOpcode() == BO_LOr), LTest, RTest)));
break;
}
case BO_PtrMemD:
case BO_PtrMemI:
forwardInfo(BinOp->getLHS(), BinOp);
break;
default:
break;
}
}
void ConsumedStmtVisitor::VisitCallExpr(const CallExpr *Call) {
const FunctionDecl *FunDecl = Call->getDirectCallee();
if (!FunDecl)
return;
// Special case for the std::move function.
// TODO: Make this more specific. (Deferred)
if (Call->isCallToStdMove()) {
copyInfo(Call->getArg(0), Call, CS_Consumed);
return;
}
handleCall(Call, nullptr, FunDecl);
propagateReturnType(Call, FunDecl);
}
void ConsumedStmtVisitor::VisitCastExpr(const CastExpr *Cast) {
forwardInfo(Cast->getSubExpr(), Cast);
}
void ConsumedStmtVisitor::VisitCXXBindTemporaryExpr(
const CXXBindTemporaryExpr *Temp) {
InfoEntry Entry = findInfo(Temp->getSubExpr());
if (Entry != PropagationMap.end() && !Entry->second.isTest()) {
StateMap->setState(Temp, Entry->second.getAsState(StateMap));
PropagationMap.insert(PairType(Temp, PropagationInfo(Temp)));
}
}
void ConsumedStmtVisitor::VisitCXXConstructExpr(const CXXConstructExpr *Call) {
CXXConstructorDecl *Constructor = Call->getConstructor();
QualType ThisType = Constructor->getThisType()->getPointeeType();
if (!isConsumableType(ThisType))
return;
// FIXME: What should happen if someone annotates the move constructor?
if (ReturnTypestateAttr *RTA = Constructor->getAttr<ReturnTypestateAttr>()) {
// TODO: Adjust state of args appropriately.
ConsumedState RetState = mapReturnTypestateAttrState(RTA);
PropagationMap.insert(PairType(Call, PropagationInfo(RetState)));
} else if (Constructor->isDefaultConstructor()) {
PropagationMap.insert(PairType(Call,
PropagationInfo(consumed::CS_Consumed)));
} else if (Constructor->isMoveConstructor()) {
copyInfo(Call->getArg(0), Call, CS_Consumed);
} else if (Constructor->isCopyConstructor()) {
// Copy state from arg. If setStateOnRead then set arg to CS_Unknown.
ConsumedState NS =
isSetOnReadPtrType(Constructor->getThisType()) ?
CS_Unknown : CS_None;
copyInfo(Call->getArg(0), Call, NS);
} else {
// TODO: Adjust state of args appropriately.
ConsumedState RetState = mapConsumableAttrState(ThisType);
PropagationMap.insert(PairType(Call, PropagationInfo(RetState)));
}
}
void ConsumedStmtVisitor::VisitCXXMemberCallExpr(
const CXXMemberCallExpr *Call) {
CXXMethodDecl* MD = Call->getMethodDecl();
if (!MD)
return;
handleCall(Call, Call->getImplicitObjectArgument(), MD);
propagateReturnType(Call, MD);
}
void ConsumedStmtVisitor::VisitCXXOperatorCallExpr(
const CXXOperatorCallExpr *Call) {
const auto *FunDecl = dyn_cast_or_null<FunctionDecl>(Call->getDirectCallee());
if (!FunDecl) return;
if (Call->getOperator() == OO_Equal) {
ConsumedState CS = getInfo(Call->getArg(1));
if (!handleCall(Call, Call->getArg(0), FunDecl))
setInfo(Call->getArg(0), CS);
return;
}
if (const auto *MCall = dyn_cast<CXXMemberCallExpr>(Call))
handleCall(MCall, MCall->getImplicitObjectArgument(), FunDecl);
else
handleCall(Call, Call->getArg(0), FunDecl);
propagateReturnType(Call, FunDecl);
}
void ConsumedStmtVisitor::VisitDeclRefExpr(const DeclRefExpr *DeclRef) {
if (const auto *Var = dyn_cast_or_null<VarDecl>(DeclRef->getDecl()))
if (StateMap->getState(Var) != consumed::CS_None)
PropagationMap.insert(PairType(DeclRef, PropagationInfo(Var)));
}
void ConsumedStmtVisitor::VisitDeclStmt(const DeclStmt *DeclS) {
for (const auto *DI : DeclS->decls())
if (isa<VarDecl>(DI))
VisitVarDecl(cast<VarDecl>(DI));
if (DeclS->isSingleDecl())
if (const auto *Var = dyn_cast_or_null<VarDecl>(DeclS->getSingleDecl()))
PropagationMap.insert(PairType(DeclS, PropagationInfo(Var)));
}
void ConsumedStmtVisitor::VisitMaterializeTemporaryExpr(
const MaterializeTemporaryExpr *Temp) {
forwardInfo(Temp->getSubExpr(), Temp);
}
void ConsumedStmtVisitor::VisitMemberExpr(const MemberExpr *MExpr) {
forwardInfo(MExpr->getBase(), MExpr);
}
void ConsumedStmtVisitor::VisitParmVarDecl(const ParmVarDecl *Param) {
QualType ParamType = Param->getType();
ConsumedState ParamState = consumed::CS_None;
if (const ParamTypestateAttr *PTA = Param->getAttr<ParamTypestateAttr>())
ParamState = mapParamTypestateAttrState(PTA);
else if (isConsumableType(ParamType))
ParamState = mapConsumableAttrState(ParamType);
else if (isRValueRef(ParamType) &&
isConsumableType(ParamType->getPointeeType()))
ParamState = mapConsumableAttrState(ParamType->getPointeeType());
else if (ParamType->isReferenceType() &&
isConsumableType(ParamType->getPointeeType()))
ParamState = consumed::CS_Unknown;
if (ParamState != CS_None)
StateMap->setState(Param, ParamState);
}
void ConsumedStmtVisitor::VisitReturnStmt(const ReturnStmt *Ret) {
ConsumedState ExpectedState = Analyzer.getExpectedReturnState();
if (ExpectedState != CS_None) {
InfoEntry Entry = findInfo(Ret->getRetValue());
if (Entry != PropagationMap.end()) {
ConsumedState RetState = Entry->second.getAsState(StateMap);
if (RetState != ExpectedState)
Analyzer.WarningsHandler.warnReturnTypestateMismatch(
Ret->getReturnLoc(), stateToString(ExpectedState),
stateToString(RetState));
}
}
StateMap->checkParamsForReturnTypestate(Ret->getBeginLoc(),
Analyzer.WarningsHandler);
}
void ConsumedStmtVisitor::VisitUnaryOperator(const UnaryOperator *UOp) {
InfoEntry Entry = findInfo(UOp->getSubExpr());
if (Entry == PropagationMap.end()) return;
switch (UOp->getOpcode()) {
case UO_AddrOf:
PropagationMap.insert(PairType(UOp, Entry->second));
break;
case UO_LNot:
if (Entry->second.isTest())
PropagationMap.insert(PairType(UOp, Entry->second.invertTest()));
break;
default:
break;
}
}
// TODO: See if I need to check for reference types here.
void ConsumedStmtVisitor::VisitVarDecl(const VarDecl *Var) {
if (isConsumableType(Var->getType())) {
if (Var->hasInit()) {
MapType::iterator VIT = findInfo(Var->getInit()->IgnoreImplicit());
if (VIT != PropagationMap.end()) {
PropagationInfo PInfo = VIT->second;
ConsumedState St = PInfo.getAsState(StateMap);
if (St != consumed::CS_None) {
StateMap->setState(Var, St);
return;
}
}
}
// Otherwise
StateMap->setState(Var, consumed::CS_Unknown);
}
}
static void splitVarStateForIf(const IfStmt *IfNode, const VarTestResult &Test,
ConsumedStateMap *ThenStates,
ConsumedStateMap *ElseStates) {
ConsumedState VarState = ThenStates->getState(Test.Var);
if (VarState == CS_Unknown) {
ThenStates->setState(Test.Var, Test.TestsFor);
ElseStates->setState(Test.Var, invertConsumedUnconsumed(Test.TestsFor));
} else if (VarState == invertConsumedUnconsumed(Test.TestsFor)) {
ThenStates->markUnreachable();
} else if (VarState == Test.TestsFor) {
ElseStates->markUnreachable();
}
}
static void splitVarStateForIfBinOp(const PropagationInfo &PInfo,
ConsumedStateMap *ThenStates,
ConsumedStateMap *ElseStates) {
const VarTestResult &LTest = PInfo.getLTest(),
&RTest = PInfo.getRTest();
ConsumedState LState = LTest.Var ? ThenStates->getState(LTest.Var) : CS_None,
RState = RTest.Var ? ThenStates->getState(RTest.Var) : CS_None;
if (LTest.Var) {
if (PInfo.testEffectiveOp() == EO_And) {
if (LState == CS_Unknown) {
ThenStates->setState(LTest.Var, LTest.TestsFor);
} else if (LState == invertConsumedUnconsumed(LTest.TestsFor)) {
ThenStates->markUnreachable();
} else if (LState == LTest.TestsFor && isKnownState(RState)) {
if (RState == RTest.TestsFor)
ElseStates->markUnreachable();
else
ThenStates->markUnreachable();
}
} else {
if (LState == CS_Unknown) {
ElseStates->setState(LTest.Var,
invertConsumedUnconsumed(LTest.TestsFor));
} else if (LState == LTest.TestsFor) {
ElseStates->markUnreachable();
} else if (LState == invertConsumedUnconsumed(LTest.TestsFor) &&
isKnownState(RState)) {
if (RState == RTest.TestsFor)
ElseStates->markUnreachable();
else
ThenStates->markUnreachable();
}
}
}
if (RTest.Var) {
if (PInfo.testEffectiveOp() == EO_And) {
if (RState == CS_Unknown)
ThenStates->setState(RTest.Var, RTest.TestsFor);
else if (RState == invertConsumedUnconsumed(RTest.TestsFor))
ThenStates->markUnreachable();
} else {
if (RState == CS_Unknown)
ElseStates->setState(RTest.Var,
invertConsumedUnconsumed(RTest.TestsFor));
else if (RState == RTest.TestsFor)
ElseStates->markUnreachable();
}
}
}
bool ConsumedBlockInfo::allBackEdgesVisited(const CFGBlock *CurrBlock,
const CFGBlock *TargetBlock) {
assert(CurrBlock && "Block pointer must not be NULL");
assert(TargetBlock && "TargetBlock pointer must not be NULL");
unsigned int CurrBlockOrder = VisitOrder[CurrBlock->getBlockID()];
for (CFGBlock::const_pred_iterator PI = TargetBlock->pred_begin(),
PE = TargetBlock->pred_end(); PI != PE; ++PI) {
if (*PI && CurrBlockOrder < VisitOrder[(*PI)->getBlockID()] )
return false;
}
return true;
}
void ConsumedBlockInfo::addInfo(
const CFGBlock *Block, ConsumedStateMap *StateMap,
std::unique_ptr<ConsumedStateMap> &OwnedStateMap) {
assert(Block && "Block pointer must not be NULL");
auto &Entry = StateMapsArray[Block->getBlockID()];
if (Entry) {
Entry->intersect(*StateMap);
} else if (OwnedStateMap)
Entry = std::move(OwnedStateMap);
else
Entry = std::make_unique<ConsumedStateMap>(*StateMap);
}
void ConsumedBlockInfo::addInfo(const CFGBlock *Block,
std::unique_ptr<ConsumedStateMap> StateMap) {
assert(Block && "Block pointer must not be NULL");
auto &Entry = StateMapsArray[Block->getBlockID()];
if (Entry) {
Entry->intersect(*StateMap);
} else {
Entry = std::move(StateMap);
}
}
ConsumedStateMap* ConsumedBlockInfo::borrowInfo(const CFGBlock *Block) {
assert(Block && "Block pointer must not be NULL");
assert(StateMapsArray[Block->getBlockID()] && "Block has no block info");
return StateMapsArray[Block->getBlockID()].get();
}
void ConsumedBlockInfo::discardInfo(const CFGBlock *Block) {
StateMapsArray[Block->getBlockID()] = nullptr;
}
std::unique_ptr<ConsumedStateMap>
ConsumedBlockInfo::getInfo(const CFGBlock *Block) {
assert(Block && "Block pointer must not be NULL");
auto &Entry = StateMapsArray[Block->getBlockID()];
return isBackEdgeTarget(Block) ? std::make_unique<ConsumedStateMap>(*Entry)
: std::move(Entry);
}
bool ConsumedBlockInfo::isBackEdge(const CFGBlock *From, const CFGBlock *To) {
assert(From && "From block must not be NULL");
assert(To && "From block must not be NULL");
return VisitOrder[From->getBlockID()] > VisitOrder[To->getBlockID()];
}
bool ConsumedBlockInfo::isBackEdgeTarget(const CFGBlock *Block) {
assert(Block && "Block pointer must not be NULL");
// Anything with less than two predecessors can't be the target of a back
// edge.
if (Block->pred_size() < 2)
return false;
unsigned int BlockVisitOrder = VisitOrder[Block->getBlockID()];
for (CFGBlock::const_pred_iterator PI = Block->pred_begin(),
PE = Block->pred_end(); PI != PE; ++PI) {
if (*PI && BlockVisitOrder < VisitOrder[(*PI)->getBlockID()])
return true;
}
return false;
}
void ConsumedStateMap::checkParamsForReturnTypestate(SourceLocation BlameLoc,
ConsumedWarningsHandlerBase &WarningsHandler) const {
for (const auto &DM : VarMap) {
if (isa<ParmVarDecl>(DM.first)) {
const auto *Param = cast<ParmVarDecl>(DM.first);
const ReturnTypestateAttr *RTA = Param->getAttr<ReturnTypestateAttr>();
if (!RTA)
continue;
ConsumedState ExpectedState = mapReturnTypestateAttrState(RTA);
if (DM.second != ExpectedState)
WarningsHandler.warnParamReturnTypestateMismatch(BlameLoc,
Param->getNameAsString(), stateToString(ExpectedState),
stateToString(DM.second));
}
}
}
void ConsumedStateMap::clearTemporaries() {
TmpMap.clear();
}
ConsumedState ConsumedStateMap::getState(const VarDecl *Var) const {
VarMapType::const_iterator Entry = VarMap.find(Var);
if (Entry != VarMap.end())
return Entry->second;
return CS_None;
}
ConsumedState
ConsumedStateMap::getState(const CXXBindTemporaryExpr *Tmp) const {
TmpMapType::const_iterator Entry = TmpMap.find(Tmp);
if (Entry != TmpMap.end())
return Entry->second;
return CS_None;
}
void ConsumedStateMap::intersect(const ConsumedStateMap &Other) {
ConsumedState LocalState;
if (this->From && this->From == Other.From && !Other.Reachable) {
this->markUnreachable();
return;
}
for (const auto &DM : Other.VarMap) {
LocalState = this->getState(DM.first);
if (LocalState == CS_None)
continue;
if (LocalState != DM.second)
VarMap[DM.first] = CS_Unknown;
}
}
void ConsumedStateMap::intersectAtLoopHead(const CFGBlock *LoopHead,
const CFGBlock *LoopBack, const ConsumedStateMap *LoopBackStates,
ConsumedWarningsHandlerBase &WarningsHandler) {
ConsumedState LocalState;
SourceLocation BlameLoc = getLastStmtLoc(LoopBack);
for (const auto &DM : LoopBackStates->VarMap) {
LocalState = this->getState(DM.first);
if (LocalState == CS_None)
continue;
if (LocalState != DM.second) {
VarMap[DM.first] = CS_Unknown;
WarningsHandler.warnLoopStateMismatch(BlameLoc,
DM.first->getNameAsString());
}
}
}
void ConsumedStateMap::markUnreachable() {
this->Reachable = false;
VarMap.clear();
TmpMap.clear();
}
void ConsumedStateMap::setState(const VarDecl *Var, ConsumedState State) {
VarMap[Var] = State;
}
void ConsumedStateMap::setState(const CXXBindTemporaryExpr *Tmp,
ConsumedState State) {
TmpMap[Tmp] = State;
}
void ConsumedStateMap::remove(const CXXBindTemporaryExpr *Tmp) {
TmpMap.erase(Tmp);
}
bool ConsumedStateMap::operator!=(const ConsumedStateMap *Other) const {
for (const auto &DM : Other->VarMap)
if (this->getState(DM.first) != DM.second)
return true;
return false;
}
void ConsumedAnalyzer::determineExpectedReturnState(AnalysisDeclContext &AC,
const FunctionDecl *D) {
QualType ReturnType;
if (const auto *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
ReturnType = Constructor->getThisType()->getPointeeType();
} else
ReturnType = D->getCallResultType();
if (const ReturnTypestateAttr *RTSAttr = D->getAttr<ReturnTypestateAttr>()) {
const CXXRecordDecl *RD = ReturnType->getAsCXXRecordDecl();
if (!RD || !RD->hasAttr<ConsumableAttr>()) {
// FIXME: This should be removed when template instantiation propagates
// attributes at template specialization definition, not
// declaration. When it is removed the test needs to be enabled
// in SemaDeclAttr.cpp.
WarningsHandler.warnReturnTypestateForUnconsumableType(
RTSAttr->getLocation(), ReturnType.getAsString());
ExpectedReturnState = CS_None;
} else
ExpectedReturnState = mapReturnTypestateAttrState(RTSAttr);
} else if (isConsumableType(ReturnType)) {
if (isAutoCastType(ReturnType)) // We can auto-cast the state to the
ExpectedReturnState = CS_None; // expected state.
else
ExpectedReturnState = mapConsumableAttrState(ReturnType);
}
else
ExpectedReturnState = CS_None;
}
bool ConsumedAnalyzer::splitState(const CFGBlock *CurrBlock,
const ConsumedStmtVisitor &Visitor) {
std::unique_ptr<ConsumedStateMap> FalseStates(
new ConsumedStateMap(*CurrStates));
PropagationInfo PInfo;
if (const auto *IfNode =
dyn_cast_or_null<IfStmt>(CurrBlock->getTerminator().getStmt())) {
const Expr *Cond = IfNode->getCond();
PInfo = Visitor.getInfo(Cond);
if (!PInfo.isValid() && isa<BinaryOperator>(Cond))
PInfo = Visitor.getInfo(cast<BinaryOperator>(Cond)->getRHS());
if (PInfo.isVarTest()) {
CurrStates->setSource(Cond);
FalseStates->setSource(Cond);
splitVarStateForIf(IfNode, PInfo.getVarTest(), CurrStates.get(),
FalseStates.get());
} else if (PInfo.isBinTest()) {
CurrStates->setSource(PInfo.testSourceNode());
FalseStates->setSource(PInfo.testSourceNode());
splitVarStateForIfBinOp(PInfo, CurrStates.get(), FalseStates.get());
} else {
return false;
}
} else if (const auto *BinOp =
dyn_cast_or_null<BinaryOperator>(CurrBlock->getTerminator().getStmt())) {
PInfo = Visitor.getInfo(BinOp->getLHS());
if (!PInfo.isVarTest()) {
if ((BinOp = dyn_cast_or_null<BinaryOperator>(BinOp->getLHS()))) {
PInfo = Visitor.getInfo(BinOp->getRHS());
if (!PInfo.isVarTest())
return false;
} else {
return false;
}
}
CurrStates->setSource(BinOp);
FalseStates->setSource(BinOp);
const VarTestResult &Test = PInfo.getVarTest();
ConsumedState VarState = CurrStates->getState(Test.Var);
if (BinOp->getOpcode() == BO_LAnd) {
if (VarState == CS_Unknown)
CurrStates->setState(Test.Var, Test.TestsFor);
else if (VarState == invertConsumedUnconsumed(Test.TestsFor))
CurrStates->markUnreachable();
} else if (BinOp->getOpcode() == BO_LOr) {
if (VarState == CS_Unknown)
FalseStates->setState(Test.Var,
invertConsumedUnconsumed(Test.TestsFor));
else if (VarState == Test.TestsFor)
FalseStates->markUnreachable();
}
} else {
return false;
}
CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin();
if (*SI)
BlockInfo.addInfo(*SI, std::move(CurrStates));
else
CurrStates = nullptr;
if (*++SI)
BlockInfo.addInfo(*SI, std::move(FalseStates));
return true;
}
void ConsumedAnalyzer::run(AnalysisDeclContext &AC) {
const auto *D = dyn_cast_or_null<FunctionDecl>(AC.getDecl());
if (!D)
return;
CFG *CFGraph = AC.getCFG();
if (!CFGraph)
return;
determineExpectedReturnState(AC, D);
PostOrderCFGView *SortedGraph = AC.getAnalysis<PostOrderCFGView>();
// AC.getCFG()->viewCFG(LangOptions());
BlockInfo = ConsumedBlockInfo(CFGraph->getNumBlockIDs(), SortedGraph);
CurrStates = std::make_unique<ConsumedStateMap>();
ConsumedStmtVisitor Visitor(*this, CurrStates.get());
// Add all trackable parameters to the state map.
for (const auto *PI : D->parameters())
Visitor.VisitParmVarDecl(PI);
// Visit all of the function's basic blocks.
for (const auto *CurrBlock : *SortedGraph) {
if (!CurrStates)
CurrStates = BlockInfo.getInfo(CurrBlock);
if (!CurrStates) {
continue;
} else if (!CurrStates->isReachable()) {
CurrStates = nullptr;
continue;
}
Visitor.reset(CurrStates.get());
// Visit all of the basic block's statements.
for (const auto &B : *CurrBlock) {
switch (B.getKind()) {
case CFGElement::Statement:
Visitor.Visit(B.castAs<CFGStmt>().getStmt());
break;
case CFGElement::TemporaryDtor: {
const CFGTemporaryDtor &DTor = B.castAs<CFGTemporaryDtor>();
const CXXBindTemporaryExpr *BTE = DTor.getBindTemporaryExpr();
Visitor.checkCallability(PropagationInfo(BTE),
DTor.getDestructorDecl(AC.getASTContext()),
BTE->getExprLoc());
CurrStates->remove(BTE);
break;
}
case CFGElement::AutomaticObjectDtor: {
const CFGAutomaticObjDtor &DTor = B.castAs<CFGAutomaticObjDtor>();
SourceLocation Loc = DTor.getTriggerStmt()->getEndLoc();
const VarDecl *Var = DTor.getVarDecl();
Visitor.checkCallability(PropagationInfo(Var),
DTor.getDestructorDecl(AC.getASTContext()),
Loc);
break;
}
default:
break;
}
}
// TODO: Handle other forms of branching with precision, including while-
// and for-loops. (Deferred)
if (!splitState(CurrBlock, Visitor)) {
CurrStates->setSource(nullptr);
if (CurrBlock->succ_size() > 1 ||
(CurrBlock->succ_size() == 1 &&
(*CurrBlock->succ_begin())->pred_size() > 1)) {
auto *RawState = CurrStates.get();
for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
SE = CurrBlock->succ_end(); SI != SE; ++SI) {
if (*SI == nullptr) continue;
if (BlockInfo.isBackEdge(CurrBlock, *SI)) {
BlockInfo.borrowInfo(*SI)->intersectAtLoopHead(
*SI, CurrBlock, RawState, WarningsHandler);
if (BlockInfo.allBackEdgesVisited(CurrBlock, *SI))
BlockInfo.discardInfo(*SI);
} else {
BlockInfo.addInfo(*SI, RawState, CurrStates);
}
}
CurrStates = nullptr;
}
}
if (CurrBlock == &AC.getCFG()->getExit() &&
D->getCallResultType()->isVoidType())
CurrStates->checkParamsForReturnTypestate(D->getLocation(),
WarningsHandler);
} // End of block iterator.
// Delete the last existing state map.
CurrStates = nullptr;
WarningsHandler.emitDiagnostics();
}
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