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

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//===- Consumed.cpp --------------------------------------------*- C++ --*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// A intra-procedural analysis for checking consumed properties. This is based,
// in part, on research on linear types.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/Type.h"
#include "clang/Analysis/Analyses/PostOrderCFGView.h"
#include "clang/Analysis/AnalysisContext.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/Analyses/Consumed.h"
#include "clang/Basic/OperatorKinds.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/raw_ostream.h"
// TODO: Add notes about the actual and expected state for
// TODO: Correctly identify unreachable blocks when chaining boolean operators.
// TODO: Warn about unreachable code.
// TODO: Switch to using a bitmap to track unreachable blocks.
// TODO: Mark variables as Unknown going into while- or for-loops only if they
// are referenced inside that block. (Deferred)
// TODO: Handle variable definitions, e.g. bool valid = x.isValid();
// if (valid) ...; (Deferred)
// TODO: Add a method(s) to identify which method calls perform what state
// transitions. (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() {}
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 isConsumableType(const QualType &QT) {
if (const CXXRecordDecl *RD = QT->getAsCXXRecordDecl())
return RD->hasAttr<ConsumableAttr>();
else
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 isTestingFunction(const FunctionDecl *FunDecl) {
return FunDecl->hasAttr<TestsUnconsumedAttr>();
}
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
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 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");
}
namespace {
struct VarTestResult {
const VarDecl *Var;
ConsumedState TestsFor;
};
} // end anonymous::VarTestResult
namespace clang {
namespace consumed {
enum EffectiveOp {
EO_And,
EO_Or
};
class PropagationInfo {
enum {
IT_None,
IT_State,
IT_Test,
IT_BinTest,
IT_Var
} InfoType;
struct BinTestTy {
const BinaryOperator *Source;
EffectiveOp EOp;
VarTestResult LTest;
VarTestResult RTest;
};
union {
ConsumedState State;
VarTestResult Test;
const VarDecl *Var;
BinTestTy BinTest;
};
public:
PropagationInfo() : InfoType(IT_None) {}
PropagationInfo(const VarTestResult &Test) : InfoType(IT_Test), Test(Test) {}
PropagationInfo(const VarDecl *Var, ConsumedState TestsFor)
: InfoType(IT_Test) {
Test.Var = Var;
Test.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) {}
const ConsumedState & getState() const {
assert(InfoType == IT_State);
return State;
}
const VarTestResult & getTest() const {
assert(InfoType == IT_Test);
return Test;
}
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;
}
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 isTest() const { return InfoType == IT_Test; }
bool isBinTest() const { return InfoType == IT_BinTest; }
bool isVar() const { return InfoType == IT_Var; }
PropagationInfo invertTest() const {
assert(InfoType == IT_Test || InfoType == IT_BinTest);
if (InfoType == IT_Test) {
return PropagationInfo(Test.Var, invertConsumedUnconsumed(Test.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 PropagationInfo();
}
}
};
class ConsumedStmtVisitor : public ConstStmtVisitor<ConsumedStmtVisitor> {
typedef llvm::DenseMap<const Stmt *, PropagationInfo> MapType;
typedef std::pair<const Stmt *, PropagationInfo> PairType;
typedef MapType::iterator InfoEntry;
typedef MapType::const_iterator ConstInfoEntry;
AnalysisDeclContext &AC;
ConsumedAnalyzer &Analyzer;
ConsumedStateMap *StateMap;
MapType PropagationMap;
void checkCallability(const PropagationInfo &PInfo,
const FunctionDecl *FunDecl,
const CallExpr *Call);
void forwardInfo(const Stmt *From, const Stmt *To);
void handleTestingFunctionCall(const CallExpr *Call, const VarDecl *Var);
bool isLikeMoveAssignment(const CXXMethodDecl *MethodDecl);
void propagateReturnType(const Stmt *Call, const FunctionDecl *Fun,
QualType ReturnType);
public:
void Visit(const Stmt *StmtNode);
void VisitBinaryOperator(const BinaryOperator *BinOp);
void VisitCallExpr(const CallExpr *Call);
void VisitCastExpr(const CastExpr *Cast);
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(AnalysisDeclContext &AC, ConsumedAnalyzer &Analyzer,
ConsumedStateMap *StateMap)
: AC(AC), Analyzer(Analyzer), StateMap(StateMap) {}
PropagationInfo getInfo(const Stmt *StmtNode) const {
ConstInfoEntry Entry = PropagationMap.find(StmtNode);
if (Entry != PropagationMap.end())
return Entry->second;
else
return PropagationInfo();
}
void reset(ConsumedStateMap *NewStateMap) {
StateMap = NewStateMap;
}
};
// TODO: When we support CallableWhenConsumed this will have to check for
// the different attributes and change the behavior bellow. (Deferred)
void ConsumedStmtVisitor::checkCallability(const PropagationInfo &PInfo,
const FunctionDecl *FunDecl,
const CallExpr *Call) {
if (!FunDecl->hasAttr<CallableWhenUnconsumedAttr>()) return;
if (PInfo.isVar()) {
const VarDecl *Var = PInfo.getVar();
switch (StateMap->getState(Var)) {
case CS_Consumed:
Analyzer.WarningsHandler.warnUseWhileConsumed(
FunDecl->getNameAsString(), Var->getNameAsString(),
Call->getExprLoc());
break;
case CS_Unknown:
Analyzer.WarningsHandler.warnUseInUnknownState(
FunDecl->getNameAsString(), Var->getNameAsString(),
Call->getExprLoc());
break;
case CS_None:
case CS_Unconsumed:
break;
}
} else {
switch (PInfo.getState()) {
case CS_Consumed:
Analyzer.WarningsHandler.warnUseOfTempWhileConsumed(
FunDecl->getNameAsString(), Call->getExprLoc());
break;
case CS_Unknown:
Analyzer.WarningsHandler.warnUseOfTempInUnknownState(
FunDecl->getNameAsString(), Call->getExprLoc());
break;
case CS_None:
case CS_Unconsumed:
break;
}
}
}
void ConsumedStmtVisitor::forwardInfo(const Stmt *From, const Stmt *To) {
InfoEntry Entry = PropagationMap.find(From);
if (Entry != PropagationMap.end())
PropagationMap.insert(PairType(To, Entry->second));
}
void ConsumedStmtVisitor::handleTestingFunctionCall(const CallExpr *Call,
const VarDecl *Var) {
ConsumedState VarState = StateMap->getState(Var);
if (VarState != CS_Unknown) {
SourceLocation CallLoc = Call->getExprLoc();
if (!CallLoc.isMacroID())
Analyzer.WarningsHandler.warnUnnecessaryTest(Var->getNameAsString(),
stateToString(VarState), CallLoc);
}
PropagationMap.insert(PairType(Call, PropagationInfo(Var, CS_Unconsumed)));
}
bool ConsumedStmtVisitor::isLikeMoveAssignment(
const CXXMethodDecl *MethodDecl) {
return MethodDecl->isMoveAssignmentOperator() ||
(MethodDecl->getOverloadedOperator() == OO_Equal &&
MethodDecl->getNumParams() == 1 &&
MethodDecl->getParamDecl(0)->getType()->isRValueReferenceType());
}
void ConsumedStmtVisitor::propagateReturnType(const Stmt *Call,
const FunctionDecl *Fun,
QualType ReturnType) {
if (isConsumableType(ReturnType)) {
ConsumedState ReturnState;
if (Fun->hasAttr<ReturnTypestateAttr>())
ReturnState = mapReturnTypestateAttrState(
Fun->getAttr<ReturnTypestateAttr>());
else
ReturnState = mapConsumableAttrState(ReturnType);
PropagationMap.insert(PairType(Call,
PropagationInfo(ReturnState)));
}
}
void ConsumedStmtVisitor::Visit(const Stmt *StmtNode) {
ConstStmtVisitor<ConsumedStmtVisitor>::Visit(StmtNode);
for (Stmt::const_child_iterator CI = StmtNode->child_begin(),
CE = StmtNode->child_end(); CI != CE; ++CI) {
PropagationMap.erase(*CI);
}
}
void ConsumedStmtVisitor::VisitBinaryOperator(const BinaryOperator *BinOp) {
switch (BinOp->getOpcode()) {
case BO_LAnd:
case BO_LOr : {
InfoEntry LEntry = PropagationMap.find(BinOp->getLHS()),
REntry = PropagationMap.find(BinOp->getRHS());
VarTestResult LTest, RTest;
if (LEntry != PropagationMap.end() && LEntry->second.isTest()) {
LTest = LEntry->second.getTest();
} else {
LTest.Var = NULL;
LTest.TestsFor = CS_None;
}
if (REntry != PropagationMap.end() && REntry->second.isTest()) {
RTest = REntry->second.getTest();
} else {
RTest.Var = NULL;
RTest.TestsFor = CS_None;
}
if (!(LTest.Var == NULL && RTest.Var == NULL))
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) {
if (const FunctionDecl *FunDecl =
dyn_cast_or_null<FunctionDecl>(Call->getDirectCallee())) {
// Special case for the std::move function.
// TODO: Make this more specific. (Deferred)
if (FunDecl->getNameAsString() == "move") {
InfoEntry Entry = PropagationMap.find(Call->getArg(0));
if (Entry != PropagationMap.end()) {
PropagationMap.insert(PairType(Call, Entry->second));
}
return;
}
unsigned Offset = Call->getNumArgs() - FunDecl->getNumParams();
for (unsigned Index = Offset; Index < Call->getNumArgs(); ++Index) {
QualType ParamType = FunDecl->getParamDecl(Index - Offset)->getType();
InfoEntry Entry = PropagationMap.find(Call->getArg(Index));
if (Entry == PropagationMap.end() || !Entry->second.isVar()) {
continue;
}
PropagationInfo PInfo = Entry->second;
if (ParamType->isRValueReferenceType() ||
(ParamType->isLValueReferenceType() &&
!cast<LValueReferenceType>(*ParamType).isSpelledAsLValue())) {
StateMap->setState(PInfo.getVar(), consumed::CS_Consumed);
} else if (!(ParamType.isConstQualified() ||
((ParamType->isReferenceType() ||
ParamType->isPointerType()) &&
ParamType->getPointeeType().isConstQualified()))) {
StateMap->setState(PInfo.getVar(), consumed::CS_Unknown);
}
}
propagateReturnType(Call, FunDecl, FunDecl->getCallResultType());
}
}
void ConsumedStmtVisitor::VisitCastExpr(const CastExpr *Cast) {
forwardInfo(Cast->getSubExpr(), Cast);
}
void ConsumedStmtVisitor::VisitCXXConstructExpr(const CXXConstructExpr *Call) {
CXXConstructorDecl *Constructor = Call->getConstructor();
ASTContext &CurrContext = AC.getASTContext();
QualType ThisType = Constructor->getThisType(CurrContext)->getPointeeType();
if (isConsumableType(ThisType)) {
if (Constructor->isDefaultConstructor()) {
PropagationMap.insert(PairType(Call,
PropagationInfo(consumed::CS_Consumed)));
} else if (Constructor->isMoveConstructor()) {
PropagationInfo PInfo =
PropagationMap.find(Call->getArg(0))->second;
if (PInfo.isVar()) {
const VarDecl* Var = PInfo.getVar();
PropagationMap.insert(PairType(Call,
PropagationInfo(StateMap->getState(Var))));
StateMap->setState(Var, consumed::CS_Consumed);
} else {
PropagationMap.insert(PairType(Call, PInfo));
}
} else if (Constructor->isCopyConstructor()) {
MapType::iterator Entry = PropagationMap.find(Call->getArg(0));
if (Entry != PropagationMap.end())
PropagationMap.insert(PairType(Call, Entry->second));
} else {
propagateReturnType(Call, Constructor, ThisType);
}
}
}
void ConsumedStmtVisitor::VisitCXXMemberCallExpr(
const CXXMemberCallExpr *Call) {
VisitCallExpr(Call);
InfoEntry Entry = PropagationMap.find(Call->getCallee()->IgnoreParens());
if (Entry != PropagationMap.end()) {
PropagationInfo PInfo = Entry->second;
const CXXMethodDecl *MethodDecl = Call->getMethodDecl();
checkCallability(PInfo, MethodDecl, Call);
if (PInfo.isVar()) {
if (isTestingFunction(MethodDecl))
handleTestingFunctionCall(Call, PInfo.getVar());
else if (MethodDecl->hasAttr<ConsumesAttr>())
StateMap->setState(PInfo.getVar(), consumed::CS_Consumed);
}
}
}
void ConsumedStmtVisitor::VisitCXXOperatorCallExpr(
const CXXOperatorCallExpr *Call) {
const FunctionDecl *FunDecl =
dyn_cast_or_null<FunctionDecl>(Call->getDirectCallee());
if (!FunDecl) return;
if (isa<CXXMethodDecl>(FunDecl) &&
isLikeMoveAssignment(cast<CXXMethodDecl>(FunDecl))) {
InfoEntry LEntry = PropagationMap.find(Call->getArg(0));
InfoEntry REntry = PropagationMap.find(Call->getArg(1));
PropagationInfo LPInfo, RPInfo;
if (LEntry != PropagationMap.end() &&
REntry != PropagationMap.end()) {
LPInfo = LEntry->second;
RPInfo = REntry->second;
if (LPInfo.isVar() && RPInfo.isVar()) {
StateMap->setState(LPInfo.getVar(),
StateMap->getState(RPInfo.getVar()));
StateMap->setState(RPInfo.getVar(), consumed::CS_Consumed);
PropagationMap.insert(PairType(Call, LPInfo));
} else if (LPInfo.isVar() && !RPInfo.isVar()) {
StateMap->setState(LPInfo.getVar(), RPInfo.getState());
PropagationMap.insert(PairType(Call, LPInfo));
} else if (!LPInfo.isVar() && RPInfo.isVar()) {
PropagationMap.insert(PairType(Call,
PropagationInfo(StateMap->getState(RPInfo.getVar()))));
StateMap->setState(RPInfo.getVar(), consumed::CS_Consumed);
} else {
PropagationMap.insert(PairType(Call, RPInfo));
}
} else if (LEntry != PropagationMap.end() &&
REntry == PropagationMap.end()) {
LPInfo = LEntry->second;
if (LPInfo.isVar()) {
StateMap->setState(LPInfo.getVar(), consumed::CS_Unknown);
PropagationMap.insert(PairType(Call, LPInfo));
} else {
PropagationMap.insert(PairType(Call,
PropagationInfo(consumed::CS_Unknown)));
}
} else if (LEntry == PropagationMap.end() &&
REntry != PropagationMap.end()) {
RPInfo = REntry->second;
if (RPInfo.isVar()) {
const VarDecl *Var = RPInfo.getVar();
PropagationMap.insert(PairType(Call,
PropagationInfo(StateMap->getState(Var))));
StateMap->setState(Var, consumed::CS_Consumed);
} else {
PropagationMap.insert(PairType(Call, RPInfo));
}
}
} else {
VisitCallExpr(Call);
InfoEntry Entry = PropagationMap.find(Call->getArg(0));
if (Entry != PropagationMap.end()) {
PropagationInfo PInfo = Entry->second;
checkCallability(PInfo, FunDecl, Call);
if (PInfo.isVar()) {
if (isTestingFunction(FunDecl))
handleTestingFunctionCall(Call, PInfo.getVar());
else if (FunDecl->hasAttr<ConsumesAttr>())
StateMap->setState(PInfo.getVar(), consumed::CS_Consumed);
}
}
}
}
void ConsumedStmtVisitor::VisitDeclRefExpr(const DeclRefExpr *DeclRef) {
if (const VarDecl *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 (DeclStmt::const_decl_iterator DI = DeclS->decl_begin(),
DE = DeclS->decl_end(); DI != DE; ++DI) {
if (isa<VarDecl>(*DI)) VisitVarDecl(cast<VarDecl>(*DI));
}
if (DeclS->isSingleDecl())
if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(DeclS->getSingleDecl()))
PropagationMap.insert(PairType(DeclS, PropagationInfo(Var)));
}
void ConsumedStmtVisitor::VisitMaterializeTemporaryExpr(
const MaterializeTemporaryExpr *Temp) {
InfoEntry Entry = PropagationMap.find(Temp->GetTemporaryExpr());
if (Entry != PropagationMap.end())
PropagationMap.insert(PairType(Temp, Entry->second));
}
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 (!(ParamType->isPointerType() || ParamType->isReferenceType()) &&
isConsumableType(ParamType))
ParamState = mapConsumableAttrState(ParamType);
else if (ParamType->isReferenceType() &&
isConsumableType(ParamType->getPointeeType()))
ParamState = consumed::CS_Unknown;
if (ParamState)
StateMap->setState(Param, ParamState);
}
void ConsumedStmtVisitor::VisitReturnStmt(const ReturnStmt *Ret) {
if (ConsumedState ExpectedState = Analyzer.getExpectedReturnState()) {
InfoEntry Entry = PropagationMap.find(Ret->getRetValue());
if (Entry != PropagationMap.end()) {
assert(Entry->second.isState() || Entry->second.isVar());
ConsumedState RetState = Entry->second.isState() ?
Entry->second.getState() : StateMap->getState(Entry->second.getVar());
if (RetState != ExpectedState)
Analyzer.WarningsHandler.warnReturnTypestateMismatch(
Ret->getReturnLoc(), stateToString(ExpectedState),
stateToString(RetState));
}
}
}
void ConsumedStmtVisitor::VisitUnaryOperator(const UnaryOperator *UOp) {
InfoEntry Entry = PropagationMap.find(UOp->getSubExpr()->IgnoreParens());
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() || Entry->second.isBinTest())
PropagationMap.insert(PairType(UOp, Entry->second.invertTest()));
break;
default:
break;
}
}
void ConsumedStmtVisitor::VisitVarDecl(const VarDecl *Var) {
if (isConsumableType(Var->getType())) {
if (Var->hasInit()) {
PropagationInfo PInfo =
PropagationMap.find(Var->getInit())->second;
StateMap->setState(Var, PInfo.isVar() ?
StateMap->getState(PInfo.getVar()) : PInfo.getState());
} else {
StateMap->setState(Var, consumed::CS_Unknown);
}
}
}
}} // end clang::consumed::ConsumedStmtVisitor
namespace clang {
namespace consumed {
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);
if (ElseStates)
ElseStates->setState(Test.Var, invertConsumedUnconsumed(Test.TestsFor));
} else if (VarState == invertConsumedUnconsumed(Test.TestsFor)) {
ThenStates->markUnreachable();
} else if (VarState == Test.TestsFor && ElseStates) {
ElseStates->markUnreachable();
}
}
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) {
if (ElseStates)
ElseStates->markUnreachable();
} else {
ThenStates->markUnreachable();
}
}
} else {
if (LState == CS_Unknown && ElseStates) {
ElseStates->setState(LTest.Var,
invertConsumedUnconsumed(LTest.TestsFor));
} else if (LState == LTest.TestsFor && ElseStates) {
ElseStates->markUnreachable();
} else if (LState == invertConsumedUnconsumed(LTest.TestsFor) &&
isKnownState(RState)) {
if (RState == RTest.TestsFor) {
if (ElseStates)
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 (ElseStates) {
if (RState == CS_Unknown)
ElseStates->setState(RTest.Var,
invertConsumedUnconsumed(RTest.TestsFor));
else if (RState == RTest.TestsFor)
ElseStates->markUnreachable();
}
}
}
void ConsumedBlockInfo::addInfo(const CFGBlock *Block,
ConsumedStateMap *StateMap,
bool &AlreadyOwned) {
if (VisitedBlocks.alreadySet(Block)) return;
ConsumedStateMap *Entry = StateMapsArray[Block->getBlockID()];
if (Entry) {
Entry->intersect(StateMap);
} else if (AlreadyOwned) {
StateMapsArray[Block->getBlockID()] = new ConsumedStateMap(*StateMap);
} else {
StateMapsArray[Block->getBlockID()] = StateMap;
AlreadyOwned = true;
}
}
void ConsumedBlockInfo::addInfo(const CFGBlock *Block,
ConsumedStateMap *StateMap) {
if (VisitedBlocks.alreadySet(Block)) {
delete StateMap;
return;
}
ConsumedStateMap *Entry = StateMapsArray[Block->getBlockID()];
if (Entry) {
Entry->intersect(StateMap);
delete StateMap;
} else {
StateMapsArray[Block->getBlockID()] = StateMap;
}
}
ConsumedStateMap* ConsumedBlockInfo::getInfo(const CFGBlock *Block) {
return StateMapsArray[Block->getBlockID()];
}
void ConsumedBlockInfo::markVisited(const CFGBlock *Block) {
VisitedBlocks.insert(Block);
}
ConsumedState ConsumedStateMap::getState(const VarDecl *Var) {
MapType::const_iterator Entry = Map.find(Var);
if (Entry != Map.end()) {
return Entry->second;
} else {
return CS_None;
}
}
void ConsumedStateMap::intersect(const ConsumedStateMap *Other) {
ConsumedState LocalState;
if (this->From && this->From == Other->From && !Other->Reachable) {
this->markUnreachable();
return;
}
for (MapType::const_iterator DMI = Other->Map.begin(),
DME = Other->Map.end(); DMI != DME; ++DMI) {
LocalState = this->getState(DMI->first);
if (LocalState == CS_None)
continue;
if (LocalState != DMI->second)
Map[DMI->first] = CS_Unknown;
}
}
void ConsumedStateMap::markUnreachable() {
this->Reachable = false;
Map.clear();
}
void ConsumedStateMap::makeUnknown() {
for (MapType::const_iterator DMI = Map.begin(), DME = Map.end(); DMI != DME;
++DMI) {
Map[DMI->first] = CS_Unknown;
}
}
void ConsumedStateMap::setState(const VarDecl *Var, ConsumedState State) {
Map[Var] = State;
}
void ConsumedStateMap::remove(const VarDecl *Var) {
Map.erase(Var);
}
void ConsumedAnalyzer::determineExpectedReturnState(AnalysisDeclContext &AC,
const FunctionDecl *D) {
QualType ReturnType;
if (const CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
ASTContext &CurrContext = AC.getASTContext();
ReturnType = Constructor->getThisType(CurrContext)->getPointeeType();
} else
ReturnType = D->getCallResultType();
if (D->hasAttr<ReturnTypestateAttr>()) {
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))
ExpectedReturnState = mapConsumableAttrState(ReturnType);
else
ExpectedReturnState = CS_None;
}
bool ConsumedAnalyzer::splitState(const CFGBlock *CurrBlock,
const ConsumedStmtVisitor &Visitor) {
ConsumedStateMap *FalseStates = new ConsumedStateMap(*CurrStates);
PropagationInfo PInfo;
if (const IfStmt *IfNode =
dyn_cast_or_null<IfStmt>(CurrBlock->getTerminator().getStmt())) {
bool HasElse = IfNode->getElse() != NULL;
const Stmt *Cond = IfNode->getCond();
PInfo = Visitor.getInfo(Cond);
if (!PInfo.isValid() && isa<BinaryOperator>(Cond))
PInfo = Visitor.getInfo(cast<BinaryOperator>(Cond)->getRHS());
if (PInfo.isTest()) {
CurrStates->setSource(Cond);
FalseStates->setSource(Cond);
splitVarStateForIf(IfNode, PInfo.getTest(), CurrStates,
HasElse ? FalseStates : NULL);
} else if (PInfo.isBinTest()) {
CurrStates->setSource(PInfo.testSourceNode());
FalseStates->setSource(PInfo.testSourceNode());
splitVarStateForIfBinOp(PInfo, CurrStates, HasElse ? FalseStates : NULL);
} else {
delete FalseStates;
return false;
}
} else if (const BinaryOperator *BinOp =
dyn_cast_or_null<BinaryOperator>(CurrBlock->getTerminator().getStmt())) {
PInfo = Visitor.getInfo(BinOp->getLHS());
if (!PInfo.isTest()) {
if ((BinOp = dyn_cast_or_null<BinaryOperator>(BinOp->getLHS()))) {
PInfo = Visitor.getInfo(BinOp->getRHS());
if (!PInfo.isTest()) {
delete FalseStates;
return false;
}
} else {
delete FalseStates;
return false;
}
}
CurrStates->setSource(BinOp);
FalseStates->setSource(BinOp);
const VarTestResult &Test = PInfo.getTest();
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 {
delete FalseStates;
return false;
}
CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin();
if (*SI)
BlockInfo.addInfo(*SI, CurrStates);
else
delete CurrStates;
if (*++SI)
BlockInfo.addInfo(*SI, FalseStates);
else
delete FalseStates;
CurrStates = NULL;
return true;
}
void ConsumedAnalyzer::run(AnalysisDeclContext &AC) {
const FunctionDecl *D = dyn_cast_or_null<FunctionDecl>(AC.getDecl());
if (!D)
return;
CFG *CFGraph = AC.getCFG();
if (!CFGraph)
return;
determineExpectedReturnState(AC, D);
BlockInfo = ConsumedBlockInfo(CFGraph);
PostOrderCFGView *SortedGraph = AC.getAnalysis<PostOrderCFGView>();
CurrStates = new ConsumedStateMap();
ConsumedStmtVisitor Visitor(AC, *this, CurrStates);
// Add all trackable parameters to the state map.
for (FunctionDecl::param_const_iterator PI = D->param_begin(),
PE = D->param_end(); PI != PE; ++PI) {
Visitor.VisitParmVarDecl(*PI);
}
// Visit all of the function's basic blocks.
for (PostOrderCFGView::iterator I = SortedGraph->begin(),
E = SortedGraph->end(); I != E; ++I) {
const CFGBlock *CurrBlock = *I;
BlockInfo.markVisited(CurrBlock);
if (CurrStates == NULL)
CurrStates = BlockInfo.getInfo(CurrBlock);
if (!CurrStates) {
continue;
} else if (!CurrStates->isReachable()) {
delete CurrStates;
CurrStates = NULL;
continue;
}
Visitor.reset(CurrStates);
// Visit all of the basic block's statements.
for (CFGBlock::const_iterator BI = CurrBlock->begin(),
BE = CurrBlock->end(); BI != BE; ++BI) {
switch (BI->getKind()) {
case CFGElement::Statement:
Visitor.Visit(BI->castAs<CFGStmt>().getStmt());
break;
case CFGElement::AutomaticObjectDtor:
CurrStates->remove(BI->castAs<CFGAutomaticObjDtor>().getVarDecl());
default:
break;
}
}
// TODO: Handle other forms of branching with precision, including while-
// and for-loops. (Deferred)
if (!splitState(CurrBlock, Visitor)) {
CurrStates->setSource(NULL);
if (CurrBlock->succ_size() > 1) {
CurrStates->makeUnknown();
bool OwnershipTaken = false;
for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
SE = CurrBlock->succ_end(); SI != SE; ++SI) {
if (*SI) BlockInfo.addInfo(*SI, CurrStates, OwnershipTaken);
}
if (!OwnershipTaken)
delete CurrStates;
CurrStates = NULL;
} else if (CurrBlock->succ_size() == 1 &&
(*CurrBlock->succ_begin())->pred_size() > 1) {
BlockInfo.addInfo(*CurrBlock->succ_begin(), CurrStates);
CurrStates = NULL;
}
}
} // End of block iterator.
// Delete the last existing state map.
delete CurrStates;
WarningsHandler.emitDiagnostics();
}
}} // end namespace clang::consumed
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