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llvm-project/clang/lib/Analysis/Consumed.cpp
Chris Bieneman 400d3261a0 [HLSL] Cleanup support for this as an l-value 
The goal of this change is to clean up some of the code surrounding
HLSL using CXXThisExpr as a non-pointer l-value. This change cleans up
a bunch of assumptions and inconsistencies around how the type of
`this` is handled through the AST and code generation.

This change is be mostly NFC for HLSL, and completely NFC for other
language modes.

This change introduces a new member to query for the this object's type
and seeks to clarify the normal usages of the this type.

With the introudction of HLSL to clang, CXXThisExpr may now be an
l-value and behave like a reference type rather than C++'s normal
method of it being an r-value of pointer type.

With this change there are now three ways in which a caller might need
to query the type of `this`:

* The type of the `CXXThisExpr`
* The type of the object `this` referrs to
* The type of the implicit (or explicit) `this` argument

This change codifies those three ways you may need to query
respectively as:

* CXXMethodDecl::getThisType()
* CXXMethodDecl::getThisObjectType()
* CXXMethodDecl::getThisArgType()

This change then revisits all uses of `getThisType()`, and in cases
where the only use was to resolve the pointee type, it replaces the
call with `getThisObjectType()`. In other cases it evaluates whether
the desired returned type is the type of the `this` expr, or the type
of the `this` function argument. The `this` expr type is used for
creating additional expr AST nodes and for member lookup, while the
argument type is used mostly for code generation.

Additionally some cases that used `getThisType` in simple queries could
be substituted for `getThisObjectType`. Since `getThisType` is
implemented in terms of `getThisObjectType` calling the later should be
more efficient if the former isn't needed.

Reviewed By: aaron.ballman, bogner

Differential Revision: https://reviews.llvm.org/D159247
2023-09-05 19:38:50 -05:00

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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/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include <cassert>
#include <memory>
#include <optional>
#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 (std::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 (std::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->getThisObjectType();
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->getThisObjectType();
} 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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