--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/lib/Sema/ScopeInfo.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,250 @@
+//===--- 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;
+  HasPotentialAvailabilityViolations = false;
+  ObjCShouldCallSuper = false;
+  ObjCIsDesignatedInit = false;
+  ObjCWarnForNoDesignatedInitChain = false;
+  ObjCIsSecondaryInit = false;
+  ObjCWarnForNoInitDelegation = false;
+  FirstReturnLoc = SourceLocation();
+  FirstCXXTryLoc = SourceLocation();
+  FirstSEHTryLoc = SourceLocation();
+
+  // 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();
+}
+
+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(VarDecl *, Expr *)> Callback) const {
+  for (Expr *E : PotentiallyCapturingExprs) {
+    if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
+      Callback(cast<VarDecl>(DRE->getFoundDecl()), E);
+    } else if (auto *ME = dyn_cast<MemberExpr>(E)) {
+      Callback(cast<VarDecl>(ME->getMemberDecl()), E);
+    } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(E)) {
+      for (VarDecl *VD : *FP)
+        Callback(VD, E);
+    } else {
+      llvm_unreachable("unexpected expression in potential captures list");
+    }
+  }
+}
+
+FunctionScopeInfo::~FunctionScopeInfo() { }
+BlockScopeInfo::~BlockScopeInfo() { }
+CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }