//===--- ScopeInfo.cpp - Information about a semantic context -------------===//

//

// 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

//

//===----------------------------------------------------------------------===//

//

// This file implements FunctionScopeInfo and its subclasses, which contain

// information about a single function, block, lambda, or method body.

//

//===----------------------------------------------------------------------===//

#include "clang/Sema/ScopeInfo.h"

#include "clang/AST/Decl.h"

#include "clang/AST/DeclCXX.h"

#include "clang/AST/DeclObjC.h"

#include "clang/AST/Expr.h"

#include "clang/AST/ExprCXX.h"

#include "clang/AST/ExprObjC.h"

using namespace clang;

using namespace sema;

void FunctionScopeInfo::Clear() {

  HasBranchProtectedScope = false;

  HasBranchIntoScope = false;

  HasIndirectGoto = false;

  HasDroppedStmt = false;

  HasOMPDeclareReductionCombiner = false;

  HasFallthroughStmt = false;

  UsesFPIntrin = false;

  HasPotentialAvailabilityViolations = false;

  ObjCShouldCallSuper = false;

  ObjCIsDesignatedInit = false;

  ObjCWarnForNoDesignatedInitChain = false;

  ObjCIsSecondaryInit = false;

  ObjCWarnForNoInitDelegation = false;

  FirstReturnLoc = SourceLocation();

  FirstCXXOrObjCTryLoc = SourceLocation();

  FirstSEHTryLoc = SourceLocation();

  FoundImmediateEscalatingExpression = false;

  // Coroutine state

  FirstCoroutineStmtLoc = SourceLocation();

  CoroutinePromise = nullptr;

  CoroutineParameterMoves.clear();

  NeedsCoroutineSuspends = true;

  CoroutineSuspends.first = nullptr;

  CoroutineSuspends.second = nullptr;

  SwitchStack.clear();

  Returns.clear();

  ErrorTrap.reset();

  PossiblyUnreachableDiags.clear();

  WeakObjectUses.clear();

  ModifiedNonNullParams.clear();

  Blocks.clear();

  ByrefBlockVars.clear();

  AddrLabels.clear();

}

static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {

  if (PropE->isExplicitProperty())

    return PropE->getExplicitProperty();

  return PropE->getImplicitPropertyGetter();

}

FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy

FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {

  E = E->IgnoreParenCasts();

  const NamedDecl *D = nullptr;

  bool IsExact = false;

  switch (E->getStmtClass()) {

  case Stmt::DeclRefExprClass:

    D = cast<DeclRefExpr>(E)->getDecl();

    IsExact = isa<VarDecl>(D);

    break;

  case Stmt::MemberExprClass: {

    const MemberExpr *ME = cast<MemberExpr>(E);

    D = ME->getMemberDecl();

    IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());

    break;

  }

  case Stmt::ObjCIvarRefExprClass: {

    const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);

    D = IE->getDecl();

    IsExact = IE->getBase()->isObjCSelfExpr();

    break;

  }

  case Stmt::PseudoObjectExprClass: {

    const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);

    const ObjCPropertyRefExpr *BaseProp =

      dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());

    if (BaseProp) {

      D = getBestPropertyDecl(BaseProp);

      if (BaseProp->isObjectReceiver()) {

        const Expr *DoubleBase = BaseProp->getBase();

        if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))

          DoubleBase = OVE->getSourceExpr();

        IsExact = DoubleBase->isObjCSelfExpr();

      }

    }

    break;

  }

  default:

    break;

  }

  return BaseInfoTy(D, IsExact);

}

FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(

                                          const ObjCPropertyRefExpr *PropE)

    : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {

  if (PropE->isObjectReceiver()) {

    const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());

    const Expr *E = OVE->getSourceExpr();

    Base = getBaseInfo(E);

  } else if (PropE->isClassReceiver()) {

    Base.setPointer(PropE->getClassReceiver());

  } else {

    assert(PropE->isSuperReceiver());

  }

}

FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,

                                                const ObjCPropertyDecl *Prop)

    : Base(nullptr, true), Property(Prop) {

  if (BaseE)

    Base = getBaseInfo(BaseE);

  // else, this is a message accessing a property on super.

}

FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(

                                                      const DeclRefExpr *DRE)

  : Base(nullptr, true), Property(DRE->getDecl()) {

  assert(isa<VarDecl>(Property));

}

FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(

                                                  const ObjCIvarRefExpr *IvarE)

  : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {

}

void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg,

                                        const ObjCPropertyDecl *Prop) {

  assert(Msg && Prop);

  WeakUseVector &Uses =

    WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];

  Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));

}

void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {

  E = E->IgnoreParenCasts();

  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {

    markSafeWeakUse(POE->getSyntacticForm());

    return;

  }

  if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {

    markSafeWeakUse(Cond->getTrueExpr());

    markSafeWeakUse(Cond->getFalseExpr());

    return;

  }

  if (const BinaryConditionalOperator *Cond =

        dyn_cast<BinaryConditionalOperator>(E)) {

    markSafeWeakUse(Cond->getCommon());

    markSafeWeakUse(Cond->getFalseExpr());

    return;

  }

  // Has this weak object been seen before?

  FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end();

  if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {

    if (!RefExpr->isObjectReceiver())

      return;

    if (isa<OpaqueValueExpr>(RefExpr->getBase()))

     Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));

    else {

      markSafeWeakUse(RefExpr->getBase());

      return;

    }

  }

  else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))

    Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));

  else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {

    if (isa<VarDecl>(DRE->getDecl()))

      Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));

  } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {

    if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {

      if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {

        Uses =

          WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),

                                                  Prop));

      }

    }

  }

  else

    return;

  if (Uses == WeakObjectUses.end())

    return;

  // Has there been a read from the object using this Expr?

  FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =

      llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true));

  if (ThisUse == Uses->second.rend())

    return;

  ThisUse->markSafe();

}

bool Capture::isInitCapture() const {

  // Note that a nested capture of an init-capture is not itself an

  // init-capture.

  return !isNested() && isVariableCapture() && getVariable()->isInitCapture();

}

bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {

  for (auto &Cap : Captures)

    if (Cap.isVLATypeCapture() && Cap.getCapturedVLAType() == VAT)

      return true;

  return false;

}

void LambdaScopeInfo::visitPotentialCaptures(

    llvm::function_ref<void(ValueDecl *, Expr *)> Callback) const {

  for (Expr *E : PotentiallyCapturingExprs) {

    if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {

      Callback(cast<ValueDecl>(DRE->getFoundDecl()), E);

    } else if (auto *ME = dyn_cast<MemberExpr>(E)) {

      Callback(cast<ValueDecl>(ME->getMemberDecl()), E);

    } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(E)) {

      for (ValueDecl *VD : *FP)

        Callback(VD, E);

    } else {

      llvm_unreachable("unexpected expression in potential captures list");

    }

  }

}

bool LambdaScopeInfo::lambdaCaptureShouldBeConst() const {

  if (ExplicitObjectParameter)

    return ExplicitObjectParameter->getType()

        .getNonReferenceType()

        .isConstQualified();

  return !Mutable;

}

FunctionScopeInfo::~FunctionScopeInfo() { }

BlockScopeInfo::~BlockScopeInfo() { }

CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }