Export clang-format16 via ydblib project

6e6be3a95868fde888d801b7590af4044049563f

1 files changed, 1020 insertions, 0 deletions

diff --git a/contrib/libs/clang16/lib/Sema/JumpDiagnostics.cpp b/contrib/libs/clang16/lib/Sema/JumpDiagnostics.cpp
new file mode 100644
index 0000000000..bd2ce9a93e
--- /dev/null
+++ b/contrib/libs/clang16/lib/Sema/JumpDiagnostics.cpp
@@ -0,0 +1,1020 @@
+//===--- JumpDiagnostics.cpp - Protected scope jump analysis ------*- C++ -*-=//
+//
+// 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 the JumpScopeChecker class, which is used to diagnose
+// jumps that enter a protected scope in an invalid way.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/AST/StmtObjC.h"
+#include "clang/AST/StmtOpenMP.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Sema/SemaInternal.h"
+#include "llvm/ADT/BitVector.h"
+using namespace clang;
+
+namespace {
+
+/// JumpScopeChecker - This object is used by Sema to diagnose invalid jumps
+/// into VLA and other protected scopes.  For example, this rejects:
+///    goto L;
+///    int a[n];
+///  L:
+///
+/// We also detect jumps out of protected scopes when it's not possible to do
+/// cleanups properly. Indirect jumps and ASM jumps can't do cleanups because
+/// the target is unknown. Return statements with \c [[clang::musttail]] cannot
+/// handle any cleanups due to the nature of a tail call.
+class JumpScopeChecker {
+  Sema &S;
+
+  /// Permissive - True when recovering from errors, in which case precautions
+  /// are taken to handle incomplete scope information.
+  const bool Permissive;
+
+  /// GotoScope - This is a record that we use to keep track of all of the
+  /// scopes that are introduced by VLAs and other things that scope jumps like
+  /// gotos.  This scope tree has nothing to do with the source scope tree,
+  /// because you can have multiple VLA scopes per compound statement, and most
+  /// compound statements don't introduce any scopes.
+  struct GotoScope {
+    /// ParentScope - The index in ScopeMap of the parent scope.  This is 0 for
+    /// the parent scope is the function body.
+    unsigned ParentScope;
+
+    /// InDiag - The note to emit if there is a jump into this scope.
+    unsigned InDiag;
+
+    /// OutDiag - The note to emit if there is an indirect jump out
+    /// of this scope.  Direct jumps always clean up their current scope
+    /// in an orderly way.
+    unsigned OutDiag;
+
+    /// Loc - Location to emit the diagnostic.
+    SourceLocation Loc;
+
+    GotoScope(unsigned parentScope, unsigned InDiag, unsigned OutDiag,
+              SourceLocation L)
+      : ParentScope(parentScope), InDiag(InDiag), OutDiag(OutDiag), Loc(L) {}
+  };
+
+  SmallVector<GotoScope, 48> Scopes;
+  llvm::DenseMap<Stmt*, unsigned> LabelAndGotoScopes;
+  SmallVector<Stmt*, 16> Jumps;
+
+  SmallVector<Stmt*, 4> IndirectJumps;
+  SmallVector<Stmt*, 4> AsmJumps;
+  SmallVector<AttributedStmt *, 4> MustTailStmts;
+  SmallVector<LabelDecl*, 4> IndirectJumpTargets;
+  SmallVector<LabelDecl*, 4> AsmJumpTargets;
+public:
+  JumpScopeChecker(Stmt *Body, Sema &S);
+private:
+  void BuildScopeInformation(Decl *D, unsigned &ParentScope);
+  void BuildScopeInformation(VarDecl *D, const BlockDecl *BDecl,
+                             unsigned &ParentScope);
+  void BuildScopeInformation(CompoundLiteralExpr *CLE, unsigned &ParentScope);
+  void BuildScopeInformation(Stmt *S, unsigned &origParentScope);
+
+  void VerifyJumps();
+  void VerifyIndirectOrAsmJumps(bool IsAsmGoto);
+  void VerifyMustTailStmts();
+  void NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes);
+  void DiagnoseIndirectOrAsmJump(Stmt *IG, unsigned IGScope, LabelDecl *Target,
+                                 unsigned TargetScope);
+  void CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
+                 unsigned JumpDiag, unsigned JumpDiagWarning,
+                 unsigned JumpDiagCXX98Compat);
+  void CheckGotoStmt(GotoStmt *GS);
+  const Attr *GetMustTailAttr(AttributedStmt *AS);
+
+  unsigned GetDeepestCommonScope(unsigned A, unsigned B);
+};
+} // end anonymous namespace
+
+#define CHECK_PERMISSIVE(x) (assert(Permissive || !(x)), (Permissive && (x)))
+
+JumpScopeChecker::JumpScopeChecker(Stmt *Body, Sema &s)
+    : S(s), Permissive(s.hasAnyUnrecoverableErrorsInThisFunction()) {
+  // Add a scope entry for function scope.
+  Scopes.push_back(GotoScope(~0U, ~0U, ~0U, SourceLocation()));
+
+  // Build information for the top level compound statement, so that we have a
+  // defined scope record for every "goto" and label.
+  unsigned BodyParentScope = 0;
+  BuildScopeInformation(Body, BodyParentScope);
+
+  // Check that all jumps we saw are kosher.
+  VerifyJumps();
+  VerifyIndirectOrAsmJumps(false);
+  VerifyIndirectOrAsmJumps(true);
+  VerifyMustTailStmts();
+}
+
+/// GetDeepestCommonScope - Finds the innermost scope enclosing the
+/// two scopes.
+unsigned JumpScopeChecker::GetDeepestCommonScope(unsigned A, unsigned B) {
+  while (A != B) {
+    // Inner scopes are created after outer scopes and therefore have
+    // higher indices.
+    if (A < B) {
+      assert(Scopes[B].ParentScope < B);
+      B = Scopes[B].ParentScope;
+    } else {
+      assert(Scopes[A].ParentScope < A);
+      A = Scopes[A].ParentScope;
+    }
+  }
+  return A;
+}
+
+typedef std::pair<unsigned,unsigned> ScopePair;
+
+/// GetDiagForGotoScopeDecl - If this decl induces a new goto scope, return a
+/// diagnostic that should be emitted if control goes over it. If not, return 0.
+static ScopePair GetDiagForGotoScopeDecl(Sema &S, const Decl *D) {
+  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
+    unsigned InDiag = 0;
+    unsigned OutDiag = 0;
+
+    if (VD->getType()->isVariablyModifiedType())
+      InDiag = diag::note_protected_by_vla;
+
+    if (VD->hasAttr<BlocksAttr>())
+      return ScopePair(diag::note_protected_by___block,
+                       diag::note_exits___block);
+
+    if (VD->hasAttr<CleanupAttr>())
+      return ScopePair(diag::note_protected_by_cleanup,
+                       diag::note_exits_cleanup);
+
+    if (VD->hasLocalStorage()) {
+      switch (VD->getType().isDestructedType()) {
+      case QualType::DK_objc_strong_lifetime:
+        return ScopePair(diag::note_protected_by_objc_strong_init,
+                         diag::note_exits_objc_strong);
+
+      case QualType::DK_objc_weak_lifetime:
+        return ScopePair(diag::note_protected_by_objc_weak_init,
+                         diag::note_exits_objc_weak);
+
+      case QualType::DK_nontrivial_c_struct:
+        return ScopePair(diag::note_protected_by_non_trivial_c_struct_init,
+                         diag::note_exits_dtor);
+
+      case QualType::DK_cxx_destructor:
+        OutDiag = diag::note_exits_dtor;
+        break;
+
+      case QualType::DK_none:
+        break;
+      }
+    }
+
+    const Expr *Init = VD->getInit();
+    if (S.Context.getLangOpts().CPlusPlus && VD->hasLocalStorage() && Init) {
+      // C++11 [stmt.dcl]p3:
+      //   A program that jumps from a point where a variable with automatic
+      //   storage duration is not in scope to a point where it is in scope
+      //   is ill-formed unless the variable has scalar type, class type with
+      //   a trivial default constructor and a trivial destructor, a
+      //   cv-qualified version of one of these types, or an array of one of
+      //   the preceding types and is declared without an initializer.
+
+      // C++03 [stmt.dcl.p3:
+      //   A program that jumps from a point where a local variable
+      //   with automatic storage duration is not in scope to a point
+      //   where it is in scope is ill-formed unless the variable has
+      //   POD type and is declared without an initializer.
+
+      InDiag = diag::note_protected_by_variable_init;
+
+      // For a variable of (array of) class type declared without an
+      // initializer, we will have call-style initialization and the initializer
+      // will be the CXXConstructExpr with no intervening nodes.
+      if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
+        const CXXConstructorDecl *Ctor = CCE->getConstructor();
+        if (Ctor->isTrivial() && Ctor->isDefaultConstructor() &&
+            VD->getInitStyle() == VarDecl::CallInit) {
+          if (OutDiag)
+            InDiag = diag::note_protected_by_variable_nontriv_destructor;
+          else if (!Ctor->getParent()->isPOD())
+            InDiag = diag::note_protected_by_variable_non_pod;
+          else
+            InDiag = 0;
+        }
+      }
+    }
+
+    return ScopePair(InDiag, OutDiag);
+  }
+
+  if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D)) {
+    if (TD->getUnderlyingType()->isVariablyModifiedType())
+      return ScopePair(isa<TypedefDecl>(TD)
+                           ? diag::note_protected_by_vla_typedef
+                           : diag::note_protected_by_vla_type_alias,
+                       0);
+  }
+
+  return ScopePair(0U, 0U);
+}
+
+/// Build scope information for a declaration that is part of a DeclStmt.
+void JumpScopeChecker::BuildScopeInformation(Decl *D, unsigned &ParentScope) {
+  // If this decl causes a new scope, push and switch to it.
+  std::pair<unsigned,unsigned> Diags = GetDiagForGotoScopeDecl(S, D);
+  if (Diags.first || Diags.second) {
+    Scopes.push_back(GotoScope(ParentScope, Diags.first, Diags.second,
+                               D->getLocation()));
+    ParentScope = Scopes.size()-1;
+  }
+
+  // If the decl has an initializer, walk it with the potentially new
+  // scope we just installed.
+  if (VarDecl *VD = dyn_cast<VarDecl>(D))
+    if (Expr *Init = VD->getInit())
+      BuildScopeInformation(Init, ParentScope);
+}
+
+/// Build scope information for a captured block literal variables.
+void JumpScopeChecker::BuildScopeInformation(VarDecl *D,
+                                             const BlockDecl *BDecl,
+                                             unsigned &ParentScope) {
+  // exclude captured __block variables; there's no destructor
+  // associated with the block literal for them.
+  if (D->hasAttr<BlocksAttr>())
+    return;
+  QualType T = D->getType();
+  QualType::DestructionKind destructKind = T.isDestructedType();
+  if (destructKind != QualType::DK_none) {
+    std::pair<unsigned,unsigned> Diags;
+    switch (destructKind) {
+      case QualType::DK_cxx_destructor:
+        Diags = ScopePair(diag::note_enters_block_captures_cxx_obj,
+                          diag::note_exits_block_captures_cxx_obj);
+        break;
+      case QualType::DK_objc_strong_lifetime:
+        Diags = ScopePair(diag::note_enters_block_captures_strong,
+                          diag::note_exits_block_captures_strong);
+        break;
+      case QualType::DK_objc_weak_lifetime:
+        Diags = ScopePair(diag::note_enters_block_captures_weak,
+                          diag::note_exits_block_captures_weak);
+        break;
+      case QualType::DK_nontrivial_c_struct:
+        Diags = ScopePair(diag::note_enters_block_captures_non_trivial_c_struct,
+                          diag::note_exits_block_captures_non_trivial_c_struct);
+        break;
+      case QualType::DK_none:
+        llvm_unreachable("non-lifetime captured variable");
+    }
+    SourceLocation Loc = D->getLocation();
+    if (Loc.isInvalid())
+      Loc = BDecl->getLocation();
+    Scopes.push_back(GotoScope(ParentScope,
+                               Diags.first, Diags.second, Loc));
+    ParentScope = Scopes.size()-1;
+  }
+}
+
+/// Build scope information for compound literals of C struct types that are
+/// non-trivial to destruct.
+void JumpScopeChecker::BuildScopeInformation(CompoundLiteralExpr *CLE,
+                                             unsigned &ParentScope) {
+  unsigned InDiag = diag::note_enters_compound_literal_scope;
+  unsigned OutDiag = diag::note_exits_compound_literal_scope;
+  Scopes.push_back(GotoScope(ParentScope, InDiag, OutDiag, CLE->getExprLoc()));
+  ParentScope = Scopes.size() - 1;
+}
+
+/// BuildScopeInformation - The statements from CI to CE are known to form a
+/// coherent VLA scope with a specified parent node.  Walk through the
+/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
+/// walking the AST as needed.
+void JumpScopeChecker::BuildScopeInformation(Stmt *S,
+                                             unsigned &origParentScope) {
+  // If this is a statement, rather than an expression, scopes within it don't
+  // propagate out into the enclosing scope.  Otherwise we have to worry
+  // about block literals, which have the lifetime of their enclosing statement.
+  unsigned independentParentScope = origParentScope;
+  unsigned &ParentScope = ((isa<Expr>(S) && !isa<StmtExpr>(S))
+                            ? origParentScope : independentParentScope);
+
+  unsigned StmtsToSkip = 0u;
+
+  // If we found a label, remember that it is in ParentScope scope.
+  switch (S->getStmtClass()) {
+  case Stmt::AddrLabelExprClass:
+    IndirectJumpTargets.push_back(cast<AddrLabelExpr>(S)->getLabel());
+    break;
+
+  case Stmt::ObjCForCollectionStmtClass: {
+    auto *CS = cast<ObjCForCollectionStmt>(S);
+    unsigned Diag = diag::note_protected_by_objc_fast_enumeration;
+    unsigned NewParentScope = Scopes.size();
+    Scopes.push_back(GotoScope(ParentScope, Diag, 0, S->getBeginLoc()));
+    BuildScopeInformation(CS->getBody(), NewParentScope);
+    return;
+  }
+
+  case Stmt::IndirectGotoStmtClass:
+    // "goto *&&lbl;" is a special case which we treat as equivalent
+    // to a normal goto.  In addition, we don't calculate scope in the
+    // operand (to avoid recording the address-of-label use), which
+    // works only because of the restricted set of expressions which
+    // we detect as constant targets.
+    if (cast<IndirectGotoStmt>(S)->getConstantTarget()) {
+      LabelAndGotoScopes[S] = ParentScope;
+      Jumps.push_back(S);
+      return;
+    }
+
+    LabelAndGotoScopes[S] = ParentScope;
+    IndirectJumps.push_back(S);
+    break;
+
+  case Stmt::SwitchStmtClass:
+    // Evaluate the C++17 init stmt and condition variable
+    // before entering the scope of the switch statement.
+    if (Stmt *Init = cast<SwitchStmt>(S)->getInit()) {
+      BuildScopeInformation(Init, ParentScope);
+      ++StmtsToSkip;
+    }
+    if (VarDecl *Var = cast<SwitchStmt>(S)->getConditionVariable()) {
+      BuildScopeInformation(Var, ParentScope);
+      ++StmtsToSkip;
+    }
+    [[fallthrough]];
+
+  case Stmt::GotoStmtClass:
+    // Remember both what scope a goto is in as well as the fact that we have
+    // it.  This makes the second scan not have to walk the AST again.
+    LabelAndGotoScopes[S] = ParentScope;
+    Jumps.push_back(S);
+    break;
+
+  case Stmt::GCCAsmStmtClass:
+    if (auto *GS = dyn_cast<GCCAsmStmt>(S))
+      if (GS->isAsmGoto()) {
+        // Remember both what scope a goto is in as well as the fact that we
+        // have it.  This makes the second scan not have to walk the AST again.
+        LabelAndGotoScopes[S] = ParentScope;
+        AsmJumps.push_back(GS);
+        for (auto *E : GS->labels())
+          AsmJumpTargets.push_back(E->getLabel());
+      }
+    break;
+
+  case Stmt::IfStmtClass: {
+    IfStmt *IS = cast<IfStmt>(S);
+    if (!(IS->isConstexpr() || IS->isConsteval() ||
+          IS->isObjCAvailabilityCheck()))
+      break;
+
+    unsigned Diag = diag::note_protected_by_if_available;
+    if (IS->isConstexpr())
+      Diag = diag::note_protected_by_constexpr_if;
+    else if (IS->isConsteval())
+      Diag = diag::note_protected_by_consteval_if;
+
+    if (VarDecl *Var = IS->getConditionVariable())
+      BuildScopeInformation(Var, ParentScope);
+
+    // Cannot jump into the middle of the condition.
+    unsigned NewParentScope = Scopes.size();
+    Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getBeginLoc()));
+
+    if (!IS->isConsteval())
+      BuildScopeInformation(IS->getCond(), NewParentScope);
+
+    // Jumps into either arm of an 'if constexpr' are not allowed.
+    NewParentScope = Scopes.size();
+    Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getBeginLoc()));
+    BuildScopeInformation(IS->getThen(), NewParentScope);
+    if (Stmt *Else = IS->getElse()) {
+      NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getBeginLoc()));
+      BuildScopeInformation(Else, NewParentScope);
+    }
+    return;
+  }
+
+  case Stmt::CXXTryStmtClass: {
+    CXXTryStmt *TS = cast<CXXTryStmt>(S);
+    {
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_cxx_try,
+                                 diag::note_exits_cxx_try,
+                                 TS->getSourceRange().getBegin()));
+      if (Stmt *TryBlock = TS->getTryBlock())
+        BuildScopeInformation(TryBlock, NewParentScope);
+    }
+
+    // Jump from the catch into the try is not allowed either.
+    for (unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) {
+      CXXCatchStmt *CS = TS->getHandler(I);
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_cxx_catch,
+                                 diag::note_exits_cxx_catch,
+                                 CS->getSourceRange().getBegin()));
+      BuildScopeInformation(CS->getHandlerBlock(), NewParentScope);
+    }
+    return;
+  }
+
+  case Stmt::SEHTryStmtClass: {
+    SEHTryStmt *TS = cast<SEHTryStmt>(S);
+    {
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_seh_try,
+                                 diag::note_exits_seh_try,
+                                 TS->getSourceRange().getBegin()));
+      if (Stmt *TryBlock = TS->getTryBlock())
+        BuildScopeInformation(TryBlock, NewParentScope);
+    }
+
+    // Jump from __except or __finally into the __try are not allowed either.
+    if (SEHExceptStmt *Except = TS->getExceptHandler()) {
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_seh_except,
+                                 diag::note_exits_seh_except,
+                                 Except->getSourceRange().getBegin()));
+      BuildScopeInformation(Except->getBlock(), NewParentScope);
+    } else if (SEHFinallyStmt *Finally = TS->getFinallyHandler()) {
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_seh_finally,
+                                 diag::note_exits_seh_finally,
+                                 Finally->getSourceRange().getBegin()));
+      BuildScopeInformation(Finally->getBlock(), NewParentScope);
+    }
+
+    return;
+  }
+
+  case Stmt::DeclStmtClass: {
+    // If this is a declstmt with a VLA definition, it defines a scope from here
+    // to the end of the containing context.
+    DeclStmt *DS = cast<DeclStmt>(S);
+    // The decl statement creates a scope if any of the decls in it are VLAs
+    // or have the cleanup attribute.
+    for (auto *I : DS->decls())
+      BuildScopeInformation(I, origParentScope);
+    return;
+  }
+
+  case Stmt::ObjCAtTryStmtClass: {
+    // Disallow jumps into any part of an @try statement by pushing a scope and
+    // walking all sub-stmts in that scope.
+    ObjCAtTryStmt *AT = cast<ObjCAtTryStmt>(S);
+    // Recursively walk the AST for the @try part.
+    {
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_objc_try,
+                                 diag::note_exits_objc_try,
+                                 AT->getAtTryLoc()));
+      if (Stmt *TryPart = AT->getTryBody())
+        BuildScopeInformation(TryPart, NewParentScope);
+    }
+
+    // Jump from the catch to the finally or try is not valid.
+    for (ObjCAtCatchStmt *AC : AT->catch_stmts()) {
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_objc_catch,
+                                 diag::note_exits_objc_catch,
+                                 AC->getAtCatchLoc()));
+      // @catches are nested and it isn't
+      BuildScopeInformation(AC->getCatchBody(), NewParentScope);
+    }
+
+    // Jump from the finally to the try or catch is not valid.
+    if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
+      unsigned NewParentScope = Scopes.size();
+      Scopes.push_back(GotoScope(ParentScope,
+                                 diag::note_protected_by_objc_finally,
+                                 diag::note_exits_objc_finally,
+                                 AF->getAtFinallyLoc()));
+      BuildScopeInformation(AF, NewParentScope);
+    }
+
+    return;
+  }
+
+  case Stmt::ObjCAtSynchronizedStmtClass: {
+    // Disallow jumps into the protected statement of an @synchronized, but
+    // allow jumps into the object expression it protects.
+    ObjCAtSynchronizedStmt *AS = cast<ObjCAtSynchronizedStmt>(S);
+    // Recursively walk the AST for the @synchronized object expr, it is
+    // evaluated in the normal scope.
+    BuildScopeInformation(AS->getSynchExpr(), ParentScope);
+
+    // Recursively walk the AST for the @synchronized part, protected by a new
+    // scope.
+    unsigned NewParentScope = Scopes.size();
+    Scopes.push_back(GotoScope(ParentScope,
+                               diag::note_protected_by_objc_synchronized,
+                               diag::note_exits_objc_synchronized,
+                               AS->getAtSynchronizedLoc()));
+    BuildScopeInformation(AS->getSynchBody(), NewParentScope);
+    return;
+  }
+
+  case Stmt::ObjCAutoreleasePoolStmtClass: {
+    // Disallow jumps into the protected statement of an @autoreleasepool.
+    ObjCAutoreleasePoolStmt *AS = cast<ObjCAutoreleasePoolStmt>(S);
+    // Recursively walk the AST for the @autoreleasepool part, protected by a
+    // new scope.
+    unsigned NewParentScope = Scopes.size();
+    Scopes.push_back(GotoScope(ParentScope,
+                               diag::note_protected_by_objc_autoreleasepool,
+                               diag::note_exits_objc_autoreleasepool,
+                               AS->getAtLoc()));
+    BuildScopeInformation(AS->getSubStmt(), NewParentScope);
+    return;
+  }
+
+  case Stmt::ExprWithCleanupsClass: {
+    // Disallow jumps past full-expressions that use blocks with
+    // non-trivial cleanups of their captures.  This is theoretically
+    // implementable but a lot of work which we haven't felt up to doing.
+    ExprWithCleanups *EWC = cast<ExprWithCleanups>(S);
+    for (unsigned i = 0, e = EWC->getNumObjects(); i != e; ++i) {
+      if (auto *BDecl = EWC->getObject(i).dyn_cast<BlockDecl *>())
+        for (const auto &CI : BDecl->captures()) {
+          VarDecl *variable = CI.getVariable();
+          BuildScopeInformation(variable, BDecl, origParentScope);
+        }
+      else if (auto *CLE = EWC->getObject(i).dyn_cast<CompoundLiteralExpr *>())
+        BuildScopeInformation(CLE, origParentScope);
+      else
+        llvm_unreachable("unexpected cleanup object type");
+    }
+    break;
+  }
+
+  case Stmt::MaterializeTemporaryExprClass: {
+    // Disallow jumps out of scopes containing temporaries lifetime-extended to
+    // automatic storage duration.
+    MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(S);
+    if (MTE->getStorageDuration() == SD_Automatic) {
+      SmallVector<const Expr *, 4> CommaLHS;
+      SmallVector<SubobjectAdjustment, 4> Adjustments;
+      const Expr *ExtendedObject =
+          MTE->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHS,
+                                                            Adjustments);
+      if (ExtendedObject->getType().isDestructedType()) {
+        Scopes.push_back(GotoScope(ParentScope, 0,
+                                   diag::note_exits_temporary_dtor,
+                                   ExtendedObject->getExprLoc()));
+        origParentScope = Scopes.size()-1;
+      }
+    }
+    break;
+  }
+
+  case Stmt::CaseStmtClass:
+  case Stmt::DefaultStmtClass:
+  case Stmt::LabelStmtClass:
+    LabelAndGotoScopes[S] = ParentScope;
+    break;
+
+  case Stmt::AttributedStmtClass: {
+    AttributedStmt *AS = cast<AttributedStmt>(S);
+    if (GetMustTailAttr(AS)) {
+      LabelAndGotoScopes[AS] = ParentScope;
+      MustTailStmts.push_back(AS);
+    }
+    break;
+  }
+
+  default:
+    if (auto *ED = dyn_cast<OMPExecutableDirective>(S)) {
+      if (!ED->isStandaloneDirective()) {
+        unsigned NewParentScope = Scopes.size();
+        Scopes.emplace_back(ParentScope,
+                            diag::note_omp_protected_structured_block,
+                            diag::note_omp_exits_structured_block,
+                            ED->getStructuredBlock()->getBeginLoc());
+        BuildScopeInformation(ED->getStructuredBlock(), NewParentScope);
+        return;
+      }
+    }
+    break;
+  }
+
+  for (Stmt *SubStmt : S->children()) {
+    if (!SubStmt)
+        continue;
+    if (StmtsToSkip) {
+      --StmtsToSkip;
+      continue;
+    }
+
+    // Cases, labels, and defaults aren't "scope parents".  It's also
+    // important to handle these iteratively instead of recursively in
+    // order to avoid blowing out the stack.
+    while (true) {
+      Stmt *Next;
+      if (SwitchCase *SC = dyn_cast<SwitchCase>(SubStmt))
+        Next = SC->getSubStmt();
+      else if (LabelStmt *LS = dyn_cast<LabelStmt>(SubStmt))
+        Next = LS->getSubStmt();
+      else
+        break;
+
+      LabelAndGotoScopes[SubStmt] = ParentScope;
+      SubStmt = Next;
+    }
+
+    // Recursively walk the AST.
+    BuildScopeInformation(SubStmt, ParentScope);
+  }
+}
+
+/// VerifyJumps - Verify each element of the Jumps array to see if they are
+/// valid, emitting diagnostics if not.
+void JumpScopeChecker::VerifyJumps() {
+  while (!Jumps.empty()) {
+    Stmt *Jump = Jumps.pop_back_val();
+
+    // With a goto,
+    if (GotoStmt *GS = dyn_cast<GotoStmt>(Jump)) {
+      // The label may not have a statement if it's coming from inline MS ASM.
+      if (GS->getLabel()->getStmt()) {
+        CheckJump(GS, GS->getLabel()->getStmt(), GS->getGotoLoc(),
+                  diag::err_goto_into_protected_scope,
+                  diag::ext_goto_into_protected_scope,
+                  diag::warn_cxx98_compat_goto_into_protected_scope);
+      }
+      CheckGotoStmt(GS);
+      continue;
+    }
+
+    // We only get indirect gotos here when they have a constant target.
+    if (IndirectGotoStmt *IGS = dyn_cast<IndirectGotoStmt>(Jump)) {
+      LabelDecl *Target = IGS->getConstantTarget();
+      CheckJump(IGS, Target->getStmt(), IGS->getGotoLoc(),
+                diag::err_goto_into_protected_scope,
+                diag::ext_goto_into_protected_scope,
+                diag::warn_cxx98_compat_goto_into_protected_scope);
+      continue;
+    }
+
+    SwitchStmt *SS = cast<SwitchStmt>(Jump);
+    for (SwitchCase *SC = SS->getSwitchCaseList(); SC;
+         SC = SC->getNextSwitchCase()) {
+      if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(SC)))
+        continue;
+      SourceLocation Loc;
+      if (CaseStmt *CS = dyn_cast<CaseStmt>(SC))
+        Loc = CS->getBeginLoc();
+      else if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC))
+        Loc = DS->getBeginLoc();
+      else
+        Loc = SC->getBeginLoc();
+      CheckJump(SS, SC, Loc, diag::err_switch_into_protected_scope, 0,
+                diag::warn_cxx98_compat_switch_into_protected_scope);
+    }
+  }
+}
+
+/// VerifyIndirectOrAsmJumps - Verify whether any possible indirect goto or
+/// asm goto jump might cross a protection boundary.  Unlike direct jumps,
+/// indirect or asm goto jumps count cleanups as protection boundaries:
+/// since there's no way to know where the jump is going, we can't implicitly
+/// run the right cleanups the way we can with direct jumps.
+/// Thus, an indirect/asm jump is "trivial" if it bypasses no
+/// initializations and no teardowns.  More formally, an indirect/asm jump
+/// from A to B is trivial if the path out from A to DCA(A,B) is
+/// trivial and the path in from DCA(A,B) to B is trivial, where
+/// DCA(A,B) is the deepest common ancestor of A and B.
+/// Jump-triviality is transitive but asymmetric.
+///
+/// A path in is trivial if none of the entered scopes have an InDiag.
+/// A path out is trivial is none of the exited scopes have an OutDiag.
+///
+/// Under these definitions, this function checks that the indirect
+/// jump between A and B is trivial for every indirect goto statement A
+/// and every label B whose address was taken in the function.
+void JumpScopeChecker::VerifyIndirectOrAsmJumps(bool IsAsmGoto) {
+  SmallVector<Stmt*, 4> GotoJumps = IsAsmGoto ? AsmJumps : IndirectJumps;
+  if (GotoJumps.empty())
+    return;
+  SmallVector<LabelDecl *, 4> JumpTargets =
+      IsAsmGoto ? AsmJumpTargets : IndirectJumpTargets;
+  // If there aren't any address-of-label expressions in this function,
+  // complain about the first indirect goto.
+  if (JumpTargets.empty()) {
+    assert(!IsAsmGoto &&"only indirect goto can get here");
+    S.Diag(GotoJumps[0]->getBeginLoc(),
+           diag::err_indirect_goto_without_addrlabel);
+    return;
+  }
+  // Collect a single representative of every scope containing an
+  // indirect or asm goto.  For most code bases, this substantially cuts
+  // down on the number of jump sites we'll have to consider later.
+  typedef std::pair<unsigned, Stmt*> JumpScope;
+  SmallVector<JumpScope, 32> JumpScopes;
+  {
+    llvm::DenseMap<unsigned, Stmt*> JumpScopesMap;
+    for (SmallVectorImpl<Stmt *>::iterator I = GotoJumps.begin(),
+                                           E = GotoJumps.end();
+         I != E; ++I) {
+      Stmt *IG = *I;
+      if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(IG)))
+        continue;
+      unsigned IGScope = LabelAndGotoScopes[IG];
+      Stmt *&Entry = JumpScopesMap[IGScope];
+      if (!Entry) Entry = IG;
+    }
+    JumpScopes.reserve(JumpScopesMap.size());
+    for (llvm::DenseMap<unsigned, Stmt *>::iterator I = JumpScopesMap.begin(),
+                                                    E = JumpScopesMap.end();
+         I != E; ++I)
+      JumpScopes.push_back(*I);
+  }
+
+  // Collect a single representative of every scope containing a
+  // label whose address was taken somewhere in the function.
+  // For most code bases, there will be only one such scope.
+  llvm::DenseMap<unsigned, LabelDecl*> TargetScopes;
+  for (SmallVectorImpl<LabelDecl *>::iterator I = JumpTargets.begin(),
+                                              E = JumpTargets.end();
+       I != E; ++I) {
+    LabelDecl *TheLabel = *I;
+    if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(TheLabel->getStmt())))
+      continue;
+    unsigned LabelScope = LabelAndGotoScopes[TheLabel->getStmt()];
+    LabelDecl *&Target = TargetScopes[LabelScope];
+    if (!Target) Target = TheLabel;
+  }
+
+  // For each target scope, make sure it's trivially reachable from
+  // every scope containing a jump site.
+  //
+  // A path between scopes always consists of exitting zero or more
+  // scopes, then entering zero or more scopes.  We build a set of
+  // of scopes S from which the target scope can be trivially
+  // entered, then verify that every jump scope can be trivially
+  // exitted to reach a scope in S.
+  llvm::BitVector Reachable(Scopes.size(), false);
+  for (llvm::DenseMap<unsigned,LabelDecl*>::iterator
+         TI = TargetScopes.begin(), TE = TargetScopes.end(); TI != TE; ++TI) {
+    unsigned TargetScope = TI->first;
+    LabelDecl *TargetLabel = TI->second;
+
+    Reachable.reset();
+
+    // Mark all the enclosing scopes from which you can safely jump
+    // into the target scope.  'Min' will end up being the index of
+    // the shallowest such scope.
+    unsigned Min = TargetScope;
+    while (true) {
+      Reachable.set(Min);
+
+      // Don't go beyond the outermost scope.
+      if (Min == 0) break;
+
+      // Stop if we can't trivially enter the current scope.
+      if (Scopes[Min].InDiag) break;
+
+      Min = Scopes[Min].ParentScope;
+    }
+
+    // Walk through all the jump sites, checking that they can trivially
+    // reach this label scope.
+    for (SmallVectorImpl<JumpScope>::iterator
+           I = JumpScopes.begin(), E = JumpScopes.end(); I != E; ++I) {
+      unsigned Scope = I->first;
+
+      // Walk out the "scope chain" for this scope, looking for a scope
+      // we've marked reachable.  For well-formed code this amortizes
+      // to O(JumpScopes.size() / Scopes.size()):  we only iterate
+      // when we see something unmarked, and in well-formed code we
+      // mark everything we iterate past.
+      bool IsReachable = false;
+      while (true) {
+        if (Reachable.test(Scope)) {
+          // If we find something reachable, mark all the scopes we just
+          // walked through as reachable.
+          for (unsigned S = I->first; S != Scope; S = Scopes[S].ParentScope)
+            Reachable.set(S);
+          IsReachable = true;
+          break;
+        }
+
+        // Don't walk out if we've reached the top-level scope or we've
+        // gotten shallower than the shallowest reachable scope.
+        if (Scope == 0 || Scope < Min) break;
+
+        // Don't walk out through an out-diagnostic.
+        if (Scopes[Scope].OutDiag) break;
+
+        Scope = Scopes[Scope].ParentScope;
+      }
+
+      // Only diagnose if we didn't find something.
+      if (IsReachable) continue;
+
+      DiagnoseIndirectOrAsmJump(I->second, I->first, TargetLabel, TargetScope);
+    }
+  }
+}
+
+/// Return true if a particular error+note combination must be downgraded to a
+/// warning in Microsoft mode.
+static bool IsMicrosoftJumpWarning(unsigned JumpDiag, unsigned InDiagNote) {
+  return (JumpDiag == diag::err_goto_into_protected_scope &&
+         (InDiagNote == diag::note_protected_by_variable_init ||
+          InDiagNote == diag::note_protected_by_variable_nontriv_destructor));
+}
+
+/// Return true if a particular note should be downgraded to a compatibility
+/// warning in C++11 mode.
+static bool IsCXX98CompatWarning(Sema &S, unsigned InDiagNote) {
+  return S.getLangOpts().CPlusPlus11 &&
+         InDiagNote == diag::note_protected_by_variable_non_pod;
+}
+
+/// Produce primary diagnostic for an indirect jump statement.
+static void DiagnoseIndirectOrAsmJumpStmt(Sema &S, Stmt *Jump,
+                                          LabelDecl *Target, bool &Diagnosed) {
+  if (Diagnosed)
+    return;
+  bool IsAsmGoto = isa<GCCAsmStmt>(Jump);
+  S.Diag(Jump->getBeginLoc(), diag::err_indirect_goto_in_protected_scope)
+      << IsAsmGoto;
+  S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target)
+      << IsAsmGoto;
+  Diagnosed = true;
+}
+
+/// Produce note diagnostics for a jump into a protected scope.
+void JumpScopeChecker::NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes) {
+  if (CHECK_PERMISSIVE(ToScopes.empty()))
+    return;
+  for (unsigned I = 0, E = ToScopes.size(); I != E; ++I)
+    if (Scopes[ToScopes[I]].InDiag)
+      S.Diag(Scopes[ToScopes[I]].Loc, Scopes[ToScopes[I]].InDiag);
+}
+
+/// Diagnose an indirect jump which is known to cross scopes.
+void JumpScopeChecker::DiagnoseIndirectOrAsmJump(Stmt *Jump, unsigned JumpScope,
+                                                 LabelDecl *Target,
+                                                 unsigned TargetScope) {
+  if (CHECK_PERMISSIVE(JumpScope == TargetScope))
+    return;
+
+  unsigned Common = GetDeepestCommonScope(JumpScope, TargetScope);
+  bool Diagnosed = false;
+
+  // Walk out the scope chain until we reach the common ancestor.
+  for (unsigned I = JumpScope; I != Common; I = Scopes[I].ParentScope)
+    if (Scopes[I].OutDiag) {
+      DiagnoseIndirectOrAsmJumpStmt(S, Jump, Target, Diagnosed);
+      S.Diag(Scopes[I].Loc, Scopes[I].OutDiag);
+    }
+
+  SmallVector<unsigned, 10> ToScopesCXX98Compat;
+
+  // Now walk into the scopes containing the label whose address was taken.
+  for (unsigned I = TargetScope; I != Common; I = Scopes[I].ParentScope)
+    if (IsCXX98CompatWarning(S, Scopes[I].InDiag))
+      ToScopesCXX98Compat.push_back(I);
+    else if (Scopes[I].InDiag) {
+      DiagnoseIndirectOrAsmJumpStmt(S, Jump, Target, Diagnosed);
+      S.Diag(Scopes[I].Loc, Scopes[I].InDiag);
+    }
+
+  // Diagnose this jump if it would be ill-formed in C++98.
+  if (!Diagnosed && !ToScopesCXX98Compat.empty()) {
+    bool IsAsmGoto = isa<GCCAsmStmt>(Jump);
+    S.Diag(Jump->getBeginLoc(),
+           diag::warn_cxx98_compat_indirect_goto_in_protected_scope)
+        << IsAsmGoto;
+    S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target)
+        << IsAsmGoto;
+    NoteJumpIntoScopes(ToScopesCXX98Compat);
+  }
+}
+
+/// CheckJump - Validate that the specified jump statement is valid: that it is
+/// jumping within or out of its current scope, not into a deeper one.
+void JumpScopeChecker::CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
+                               unsigned JumpDiagError, unsigned JumpDiagWarning,
+                                 unsigned JumpDiagCXX98Compat) {
+  if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(From)))
+    return;
+  if (CHECK_PERMISSIVE(!LabelAndGotoScopes.count(To)))
+    return;
+
+  unsigned FromScope = LabelAndGotoScopes[From];
+  unsigned ToScope = LabelAndGotoScopes[To];
+
+  // Common case: exactly the same scope, which is fine.
+  if (FromScope == ToScope) return;
+
+  // Warn on gotos out of __finally blocks.
+  if (isa<GotoStmt>(From) || isa<IndirectGotoStmt>(From)) {
+    // If FromScope > ToScope, FromScope is more nested and the jump goes to a
+    // less nested scope.  Check if it crosses a __finally along the way.
+    for (unsigned I = FromScope; I > ToScope; I = Scopes[I].ParentScope) {
+      if (Scopes[I].InDiag == diag::note_protected_by_seh_finally) {
+        S.Diag(From->getBeginLoc(), diag::warn_jump_out_of_seh_finally);
+        break;
+      }
+      if (Scopes[I].InDiag == diag::note_omp_protected_structured_block) {
+        S.Diag(From->getBeginLoc(), diag::err_goto_into_protected_scope);
+        S.Diag(To->getBeginLoc(), diag::note_omp_exits_structured_block);
+        break;
+      }
+    }
+  }
+
+  unsigned CommonScope = GetDeepestCommonScope(FromScope, ToScope);
+
+  // It's okay to jump out from a nested scope.
+  if (CommonScope == ToScope) return;
+
+  // Pull out (and reverse) any scopes we might need to diagnose skipping.
+  SmallVector<unsigned, 10> ToScopesCXX98Compat;
+  SmallVector<unsigned, 10> ToScopesError;
+  SmallVector<unsigned, 10> ToScopesWarning;
+  for (unsigned I = ToScope; I != CommonScope; I = Scopes[I].ParentScope) {
+    if (S.getLangOpts().MSVCCompat && JumpDiagWarning != 0 &&
+        IsMicrosoftJumpWarning(JumpDiagError, Scopes[I].InDiag))
+      ToScopesWarning.push_back(I);
+    else if (IsCXX98CompatWarning(S, Scopes[I].InDiag))
+      ToScopesCXX98Compat.push_back(I);
+    else if (Scopes[I].InDiag)
+      ToScopesError.push_back(I);
+  }
+
+  // Handle warnings.
+  if (!ToScopesWarning.empty()) {
+    S.Diag(DiagLoc, JumpDiagWarning);
+    NoteJumpIntoScopes(ToScopesWarning);
+    assert(isa<LabelStmt>(To));
+    LabelStmt *Label = cast<LabelStmt>(To);
+    Label->setSideEntry(true);
+  }
+
+  // Handle errors.
+  if (!ToScopesError.empty()) {
+    S.Diag(DiagLoc, JumpDiagError);
+    NoteJumpIntoScopes(ToScopesError);
+  }
+
+  // Handle -Wc++98-compat warnings if the jump is well-formed.
+  if (ToScopesError.empty() && !ToScopesCXX98Compat.empty()) {
+    S.Diag(DiagLoc, JumpDiagCXX98Compat);
+    NoteJumpIntoScopes(ToScopesCXX98Compat);
+  }
+}
+
+void JumpScopeChecker::CheckGotoStmt(GotoStmt *GS) {
+  if (GS->getLabel()->isMSAsmLabel()) {
+    S.Diag(GS->getGotoLoc(), diag::err_goto_ms_asm_label)
+        << GS->getLabel()->getIdentifier();
+    S.Diag(GS->getLabel()->getLocation(), diag::note_goto_ms_asm_label)
+        << GS->getLabel()->getIdentifier();
+  }
+}
+
+void JumpScopeChecker::VerifyMustTailStmts() {
+  for (AttributedStmt *AS : MustTailStmts) {
+    for (unsigned I = LabelAndGotoScopes[AS]; I; I = Scopes[I].ParentScope) {
+      if (Scopes[I].OutDiag) {
+        S.Diag(AS->getBeginLoc(), diag::err_musttail_scope);
+        S.Diag(Scopes[I].Loc, Scopes[I].OutDiag);
+      }
+    }
+  }
+}
+
+const Attr *JumpScopeChecker::GetMustTailAttr(AttributedStmt *AS) {
+  ArrayRef<const Attr *> Attrs = AS->getAttrs();
+  const auto *Iter =
+      llvm::find_if(Attrs, [](const Attr *A) { return isa<MustTailAttr>(A); });
+  return Iter != Attrs.end() ? *Iter : nullptr;
+}
+
+void Sema::DiagnoseInvalidJumps(Stmt *Body) {
+  (void)JumpScopeChecker(Body, *this);
+}