167bc6071d7abea2d4870bc4fd8f119ebd93c46f3Francois Pichet//===--- JumpDiagnostics.cpp - Protected scope jump analysis ------*- C++ -*-=//
25af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//
35af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//                     The LLVM Compiler Infrastructure
45af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//
55af280ce21af061f96b5b5b752746871e364ba99Chris Lattner// This file is distributed under the University of Illinois Open Source
65af280ce21af061f96b5b5b752746871e364ba99Chris Lattner// License. See LICENSE.TXT for details.
75af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//
85af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//===----------------------------------------------------------------------===//
95af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//
105af280ce21af061f96b5b5b752746871e364ba99Chris Lattner// This file implements the JumpScopeChecker class, which is used to diagnose
1167bc6071d7abea2d4870bc4fd8f119ebd93c46f3Francois Pichet// jumps that enter a protected scope in an invalid way.
125af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//
135af280ce21af061f96b5b5b752746871e364ba99Chris Lattner//===----------------------------------------------------------------------===//
145af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
152d88708cbe4e4ec5e04e4acb6bd7f5be68557379John McCall#include "clang/Sema/SemaInternal.h"
16384aff8b94bb0d1ad6c5667b90621e5699815bb2John McCall#include "clang/AST/DeclCXX.h"
175af280ce21af061f96b5b5b752746871e364ba99Chris Lattner#include "clang/AST/Expr.h"
18e413516d0ed61ef9e2ff706bcc00480adca947c4Douglas Gregor#include "clang/AST/ExprCXX.h"
1916f0049415ec596504891259e2a83e19871c0d52Chris Lattner#include "clang/AST/StmtObjC.h"
20972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl#include "clang/AST/StmtCXX.h"
21e737f5041a36d0befb39ffeed8d50ba15916d3daDouglas Gregor#include "llvm/ADT/BitVector.h"
225af280ce21af061f96b5b5b752746871e364ba99Chris Lattnerusing namespace clang;
235af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
245af280ce21af061f96b5b5b752746871e364ba99Chris Lattnernamespace {
255af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
265af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// JumpScopeChecker - This object is used by Sema to diagnose invalid jumps
275af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// into VLA and other protected scopes.  For example, this rejects:
285af280ce21af061f96b5b5b752746871e364ba99Chris Lattner///    goto L;
295af280ce21af061f96b5b5b752746871e364ba99Chris Lattner///    int a[n];
305af280ce21af061f96b5b5b752746871e364ba99Chris Lattner///  L:
315af280ce21af061f96b5b5b752746871e364ba99Chris Lattner///
325af280ce21af061f96b5b5b752746871e364ba99Chris Lattnerclass JumpScopeChecker {
335af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  Sema &S;
341eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
355af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  /// GotoScope - This is a record that we use to keep track of all of the
365af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  /// scopes that are introduced by VLAs and other things that scope jumps like
375af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  /// gotos.  This scope tree has nothing to do with the source scope tree,
385af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  /// because you can have multiple VLA scopes per compound statement, and most
395af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  /// compound statements don't introduce any scopes.
405af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  struct GotoScope {
415af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    /// ParentScope - The index in ScopeMap of the parent scope.  This is 0 for
425af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    /// the parent scope is the function body.
435af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    unsigned ParentScope;
441eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
450e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    /// InDiag - The note to emit if there is a jump into this scope.
46ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    unsigned InDiag;
47ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
480e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    /// OutDiag - The note to emit if there is an indirect jump out
49ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    /// of this scope.  Direct jumps always clean up their current scope
50ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    /// in an orderly way.
51ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    unsigned OutDiag;
521eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
535af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    /// Loc - Location to emit the diagnostic.
545af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    SourceLocation Loc;
551eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
56ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    GotoScope(unsigned parentScope, unsigned InDiag, unsigned OutDiag,
57ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall              SourceLocation L)
58ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      : ParentScope(parentScope), InDiag(InDiag), OutDiag(OutDiag), Loc(L) {}
595af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  };
601eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
615f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner  SmallVector<GotoScope, 48> Scopes;
625af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  llvm::DenseMap<Stmt*, unsigned> LabelAndGotoScopes;
635f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner  SmallVector<Stmt*, 16> Jumps;
64ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
655f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner  SmallVector<IndirectGotoStmt*, 4> IndirectJumps;
665f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner  SmallVector<LabelDecl*, 4> IndirectJumpTargets;
675af280ce21af061f96b5b5b752746871e364ba99Chris Lattnerpublic:
685af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  JumpScopeChecker(Stmt *Body, Sema &S);
695af280ce21af061f96b5b5b752746871e364ba99Chris Lattnerprivate:
7043dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  void BuildScopeInformation(Decl *D, unsigned &ParentScope);
714e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  void BuildScopeInformation(VarDecl *D, const BlockDecl *BDecl,
724e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                             unsigned &ParentScope);
734e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  void BuildScopeInformation(Stmt *S, unsigned &origParentScope);
744e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian
755af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  void VerifyJumps();
76ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  void VerifyIndirectJumps();
774fe5be028b723fedc28bb33be96cde1ab2574ee6Bill Wendling  void NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes);
78ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  void DiagnoseIndirectJump(IndirectGotoStmt *IG, unsigned IGScope,
79ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner                            LabelDecl *Target, unsigned TargetScope);
80c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  void CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
810e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                 unsigned JumpDiag, unsigned JumpDiagWarning,
820e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                 unsigned JumpDiagCXX98Compat);
835e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall
845e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  unsigned GetDeepestCommonScope(unsigned A, unsigned B);
855af280ce21af061f96b5b5b752746871e364ba99Chris Lattner};
865af280ce21af061f96b5b5b752746871e364ba99Chris Lattner} // end anonymous namespace
875af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
885af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
895af280ce21af061f96b5b5b752746871e364ba99Chris LattnerJumpScopeChecker::JumpScopeChecker(Stmt *Body, Sema &s) : S(s) {
905af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  // Add a scope entry for function scope.
91ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  Scopes.push_back(GotoScope(~0U, ~0U, ~0U, SourceLocation()));
921eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
935af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  // Build information for the top level compound statement, so that we have a
945af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  // defined scope record for every "goto" and label.
954e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  unsigned BodyParentScope = 0;
964e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  BuildScopeInformation(Body, BodyParentScope);
971eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
985af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  // Check that all jumps we saw are kosher.
995af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  VerifyJumps();
100ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  VerifyIndirectJumps();
1015af280ce21af061f96b5b5b752746871e364ba99Chris Lattner}
1021eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
1035e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// GetDeepestCommonScope - Finds the innermost scope enclosing the
1045e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// two scopes.
1055e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCallunsigned JumpScopeChecker::GetDeepestCommonScope(unsigned A, unsigned B) {
1065e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  while (A != B) {
1075e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall    // Inner scopes are created after outer scopes and therefore have
1085e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall    // higher indices.
1095e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall    if (A < B) {
1105e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      assert(Scopes[B].ParentScope < B);
1115e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      B = Scopes[B].ParentScope;
1125e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall    } else {
1135e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      assert(Scopes[A].ParentScope < A);
1145e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      A = Scopes[A].ParentScope;
1155e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall    }
1165e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  }
1175e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  return A;
1185e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall}
1195e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall
120f85e193739c953358c865005855253af4f68a497John McCalltypedef std::pair<unsigned,unsigned> ScopePair;
121f85e193739c953358c865005855253af4f68a497John McCall
1225af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// GetDiagForGotoScopeDecl - If this decl induces a new goto scope, return a
1235af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// diagnostic that should be emitted if control goes over it. If not, return 0.
124f85e193739c953358c865005855253af4f68a497John McCallstatic ScopePair GetDiagForGotoScopeDecl(ASTContext &Context, const Decl *D) {
1255af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
126ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    unsigned InDiag = 0, OutDiag = 0;
1275af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    if (VD->getType()->isVariablyModifiedType())
128ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      InDiag = diag::note_protected_by_vla;
129ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
130f85e193739c953358c865005855253af4f68a497John McCall    if (VD->hasAttr<BlocksAttr>())
131f85e193739c953358c865005855253af4f68a497John McCall      return ScopePair(diag::note_protected_by___block,
132f85e193739c953358c865005855253af4f68a497John McCall                       diag::note_exits___block);
133f85e193739c953358c865005855253af4f68a497John McCall
134f85e193739c953358c865005855253af4f68a497John McCall    if (VD->hasAttr<CleanupAttr>())
135f85e193739c953358c865005855253af4f68a497John McCall      return ScopePair(diag::note_protected_by_cleanup,
136f85e193739c953358c865005855253af4f68a497John McCall                       diag::note_exits_cleanup);
137f85e193739c953358c865005855253af4f68a497John McCall
1384e4d08403ca5cfd4d558fa2936215d3a4e5a528dDavid Blaikie    if (Context.getLangOpts().ObjCAutoRefCount && VD->hasLocalStorage()) {
139f85e193739c953358c865005855253af4f68a497John McCall      switch (VD->getType().getObjCLifetime()) {
140f85e193739c953358c865005855253af4f68a497John McCall      case Qualifiers::OCL_None:
141f85e193739c953358c865005855253af4f68a497John McCall      case Qualifiers::OCL_ExplicitNone:
142f85e193739c953358c865005855253af4f68a497John McCall      case Qualifiers::OCL_Autoreleasing:
143f85e193739c953358c865005855253af4f68a497John McCall        break;
144f85e193739c953358c865005855253af4f68a497John McCall
145f85e193739c953358c865005855253af4f68a497John McCall      case Qualifiers::OCL_Strong:
146f85e193739c953358c865005855253af4f68a497John McCall      case Qualifiers::OCL_Weak:
147b8b0313e84700b5c6d597b3be4de41c97b7550f1Argyrios Kyrtzidis        return ScopePair(diag::note_protected_by_objc_ownership,
148b8b0313e84700b5c6d597b3be4de41c97b7550f1Argyrios Kyrtzidis                         diag::note_exits_objc_ownership);
149f85e193739c953358c865005855253af4f68a497John McCall      }
150f85e193739c953358c865005855253af4f68a497John McCall    }
151f85e193739c953358c865005855253af4f68a497John McCall
1524e4d08403ca5cfd4d558fa2936215d3a4e5a528dDavid Blaikie    if (Context.getLangOpts().CPlusPlus && VD->hasLocalStorage()) {
1530e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith      // C++11 [stmt.dcl]p3:
154f85e193739c953358c865005855253af4f68a497John McCall      //   A program that jumps from a point where a variable with automatic
155f85e193739c953358c865005855253af4f68a497John McCall      //   storage duration is not in scope to a point where it is in scope
156f85e193739c953358c865005855253af4f68a497John McCall      //   is ill-formed unless the variable has scalar type, class type with
157f85e193739c953358c865005855253af4f68a497John McCall      //   a trivial default constructor and a trivial destructor, a
158f85e193739c953358c865005855253af4f68a497John McCall      //   cv-qualified version of one of these types, or an array of one of
159f85e193739c953358c865005855253af4f68a497John McCall      //   the preceding types and is declared without an initializer.
160f85e193739c953358c865005855253af4f68a497John McCall
161f85e193739c953358c865005855253af4f68a497John McCall      // C++03 [stmt.dcl.p3:
162f85e193739c953358c865005855253af4f68a497John McCall      //   A program that jumps from a point where a local variable
163f85e193739c953358c865005855253af4f68a497John McCall      //   with automatic storage duration is not in scope to a point
164f85e193739c953358c865005855253af4f68a497John McCall      //   where it is in scope is ill-formed unless the variable has
165f85e193739c953358c865005855253af4f68a497John McCall      //   POD type and is declared without an initializer.
166f85e193739c953358c865005855253af4f68a497John McCall
167f85e193739c953358c865005855253af4f68a497John McCall      if (const Expr *init = VD->getInit()) {
168f85e193739c953358c865005855253af4f68a497John McCall        // We actually give variables of record type (or array thereof)
169f85e193739c953358c865005855253af4f68a497John McCall        // an initializer even if that initializer only calls a trivial
170f85e193739c953358c865005855253af4f68a497John McCall        // ctor.  Detect that case.
171f85e193739c953358c865005855253af4f68a497John McCall        // FIXME: With generalized initializer lists, this may
172f85e193739c953358c865005855253af4f68a497John McCall        // classify "X x{};" as having no initializer.
173f85e193739c953358c865005855253af4f68a497John McCall        unsigned inDiagToUse = diag::note_protected_by_variable_init;
174f85e193739c953358c865005855253af4f68a497John McCall
175f85e193739c953358c865005855253af4f68a497John McCall        const CXXRecordDecl *record = 0;
176f85e193739c953358c865005855253af4f68a497John McCall
177f85e193739c953358c865005855253af4f68a497John McCall        if (const CXXConstructExpr *cce = dyn_cast<CXXConstructExpr>(init)) {
178f85e193739c953358c865005855253af4f68a497John McCall          const CXXConstructorDecl *ctor = cce->getConstructor();
179f85e193739c953358c865005855253af4f68a497John McCall          record = ctor->getParent();
180f85e193739c953358c865005855253af4f68a497John McCall
181f85e193739c953358c865005855253af4f68a497John McCall          if (ctor->isTrivial() && ctor->isDefaultConstructor()) {
1820e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith            if (!record->hasTrivialDestructor())
1830e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith              inDiagToUse = diag::note_protected_by_variable_nontriv_destructor;
1840e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith            else if (!record->isPOD())
1850e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith              inDiagToUse = diag::note_protected_by_variable_non_pod;
1860e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith            else
1870e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith              inDiagToUse = 0;
188e413516d0ed61ef9e2ff706bcc00480adca947c4Douglas Gregor          }
189f85e193739c953358c865005855253af4f68a497John McCall        } else if (VD->getType()->isArrayType()) {
190f85e193739c953358c865005855253af4f68a497John McCall          record = VD->getType()->getBaseElementTypeUnsafe()
191f85e193739c953358c865005855253af4f68a497John McCall                                ->getAsCXXRecordDecl();
192e413516d0ed61ef9e2ff706bcc00480adca947c4Douglas Gregor        }
193f85e193739c953358c865005855253af4f68a497John McCall
194f85e193739c953358c865005855253af4f68a497John McCall        if (inDiagToUse)
195f85e193739c953358c865005855253af4f68a497John McCall          InDiag = inDiagToUse;
196f85e193739c953358c865005855253af4f68a497John McCall
197f85e193739c953358c865005855253af4f68a497John McCall        // Also object to indirect jumps which leave scopes with dtors.
198f85e193739c953358c865005855253af4f68a497John McCall        if (record && !record->hasTrivialDestructor())
199f61103ef335fb273a98c1389e6fddaf796feb4b3Douglas Gregor          OutDiag = diag::note_exits_dtor;
200025291b591a528d8a3f303991f65e19fa1e90a9dDouglas Gregor      }
201ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    }
2026d97e5e4b7abdae710c2548b51f4ed0298e86d80Chris Lattner
203f85e193739c953358c865005855253af4f68a497John McCall    return ScopePair(InDiag, OutDiag);
204ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  }
205ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
206ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  if (const TypedefDecl *TD = dyn_cast<TypedefDecl>(D)) {
2075af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    if (TD->getUnderlyingType()->isVariablyModifiedType())
208f85e193739c953358c865005855253af4f68a497John McCall      return ScopePair(diag::note_protected_by_vla_typedef, 0);
2095af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  }
2101eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
211162e1c1b487352434552147967c3dd296ebee2f7Richard Smith  if (const TypeAliasDecl *TD = dyn_cast<TypeAliasDecl>(D)) {
212162e1c1b487352434552147967c3dd296ebee2f7Richard Smith    if (TD->getUnderlyingType()->isVariablyModifiedType())
213f85e193739c953358c865005855253af4f68a497John McCall      return ScopePair(diag::note_protected_by_vla_type_alias, 0);
214162e1c1b487352434552147967c3dd296ebee2f7Richard Smith  }
215162e1c1b487352434552147967c3dd296ebee2f7Richard Smith
216f85e193739c953358c865005855253af4f68a497John McCall  return ScopePair(0U, 0U);
2175af280ce21af061f96b5b5b752746871e364ba99Chris Lattner}
2185af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
21943dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor/// \brief Build scope information for a declaration that is part of a DeclStmt.
22043dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregorvoid JumpScopeChecker::BuildScopeInformation(Decl *D, unsigned &ParentScope) {
22143dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  // If this decl causes a new scope, push and switch to it.
222f85e193739c953358c865005855253af4f68a497John McCall  std::pair<unsigned,unsigned> Diags = GetDiagForGotoScopeDecl(S.Context, D);
22343dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  if (Diags.first || Diags.second) {
22443dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    Scopes.push_back(GotoScope(ParentScope, Diags.first, Diags.second,
22543dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor                               D->getLocation()));
22643dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    ParentScope = Scopes.size()-1;
22743dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  }
22843dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor
22943dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  // If the decl has an initializer, walk it with the potentially new
23043dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  // scope we just installed.
23143dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  if (VarDecl *VD = dyn_cast<VarDecl>(D))
23243dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    if (Expr *Init = VD->getInit())
23343dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor      BuildScopeInformation(Init, ParentScope);
23443dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor}
2355af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
2364e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian/// \brief Build scope information for a captured block literal variables.
2374e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanianvoid JumpScopeChecker::BuildScopeInformation(VarDecl *D,
2384e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                                             const BlockDecl *BDecl,
2394e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                                             unsigned &ParentScope) {
2404e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  // exclude captured __block variables; there's no destructor
2414e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  // associated with the block literal for them.
2424e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  if (D->hasAttr<BlocksAttr>())
2434e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    return;
2444e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  QualType T = D->getType();
2454e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  QualType::DestructionKind destructKind = T.isDestructedType();
2464e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  if (destructKind != QualType::DK_none) {
2474e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    std::pair<unsigned,unsigned> Diags;
2484e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    switch (destructKind) {
2494e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      case QualType::DK_cxx_destructor:
2504e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        Diags = ScopePair(diag::note_enters_block_captures_cxx_obj,
2514e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                          diag::note_exits_block_captures_cxx_obj);
2524e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        break;
2534e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      case QualType::DK_objc_strong_lifetime:
2544e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        Diags = ScopePair(diag::note_enters_block_captures_strong,
2554e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                          diag::note_exits_block_captures_strong);
2564e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        break;
2574e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      case QualType::DK_objc_weak_lifetime:
2584e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        Diags = ScopePair(diag::note_enters_block_captures_weak,
2594e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                          diag::note_exits_block_captures_weak);
2604e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        break;
2614e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      case QualType::DK_none:
2620e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith        llvm_unreachable("non-lifetime captured variable");
2634e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    }
2644e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    SourceLocation Loc = D->getLocation();
2654e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    if (Loc.isInvalid())
2664e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      Loc = BDecl->getLocation();
2674e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    Scopes.push_back(GotoScope(ParentScope,
2684e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                               Diags.first, Diags.second, Loc));
2694e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    ParentScope = Scopes.size()-1;
2704e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  }
2714e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian}
2724e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian
2735af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// BuildScopeInformation - The statements from CI to CE are known to form a
2745af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// coherent VLA scope with a specified parent node.  Walk through the
2755af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
2765af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// walking the AST as needed.
2774e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanianvoid JumpScopeChecker::BuildScopeInformation(Stmt *S, unsigned &origParentScope) {
2784e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  // If this is a statement, rather than an expression, scopes within it don't
2794e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  // propagate out into the enclosing scope.  Otherwise we have to worry
2804e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  // about block literals, which have the lifetime of their enclosing statement.
2814e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  unsigned independentParentScope = origParentScope;
2824e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian  unsigned &ParentScope = ((isa<Expr>(S) && !isa<StmtExpr>(S))
2834e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                            ? origParentScope : independentParentScope);
2844e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian
28543dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  bool SkipFirstSubStmt = false;
28643dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor
2875af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  // If we found a label, remember that it is in ParentScope scope.
288ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  switch (S->getStmtClass()) {
289ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  case Stmt::AddrLabelExprClass:
290ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    IndirectJumpTargets.push_back(cast<AddrLabelExpr>(S)->getLabel());
291ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    break;
292ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
293ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  case Stmt::IndirectGotoStmtClass:
29495c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    // "goto *&&lbl;" is a special case which we treat as equivalent
29595c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    // to a normal goto.  In addition, we don't calculate scope in the
29695c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    // operand (to avoid recording the address-of-label use), which
29795c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    // works only because of the restricted set of expressions which
29895c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    // we detect as constant targets.
29995c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    if (cast<IndirectGotoStmt>(S)->getConstantTarget()) {
30095c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall      LabelAndGotoScopes[S] = ParentScope;
30195c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall      Jumps.push_back(S);
30295c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall      return;
30395c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    }
30495c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall
3055af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    LabelAndGotoScopes[S] = ParentScope;
306ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    IndirectJumps.push_back(cast<IndirectGotoStmt>(S));
307ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    break;
308ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
309ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  case Stmt::SwitchStmtClass:
31043dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    // Evaluate the condition variable before entering the scope of the switch
31143dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    // statement.
31243dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    if (VarDecl *Var = cast<SwitchStmt>(S)->getConditionVariable()) {
31343dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor      BuildScopeInformation(Var, ParentScope);
31443dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor      SkipFirstSubStmt = true;
31543dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    }
31643dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    // Fall through
31743dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor
31843dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor  case Stmt::GotoStmtClass:
3195af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    // Remember both what scope a goto is in as well as the fact that we have
3205af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    // it.  This makes the second scan not have to walk the AST again.
3215af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    LabelAndGotoScopes[S] = ParentScope;
3225af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    Jumps.push_back(S);
323ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    break;
324ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
325ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  default:
326ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    break;
3275af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  }
3281eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
3297502c1d3ce8bb97bcc4f7bebef507040bd93b26fJohn McCall  for (Stmt::child_range CI = S->children(); CI; ++CI) {
33043dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    if (SkipFirstSubStmt) {
33143dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor      SkipFirstSubStmt = false;
33243dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor      continue;
33343dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor    }
33443dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor
3355af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    Stmt *SubStmt = *CI;
3365af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    if (SubStmt == 0) continue;
3371eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
33897ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall    // Cases, labels, and defaults aren't "scope parents".  It's also
33997ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall    // important to handle these iteratively instead of recursively in
34097ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall    // order to avoid blowing out the stack.
34197ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall    while (true) {
34297ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall      Stmt *Next;
343ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner      if (CaseStmt *CS = dyn_cast<CaseStmt>(SubStmt))
344ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner        Next = CS->getSubStmt();
345ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner      else if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SubStmt))
346ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner        Next = DS->getSubStmt();
347ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner      else if (LabelStmt *LS = dyn_cast<LabelStmt>(SubStmt))
348ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner        Next = LS->getSubStmt();
34997ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall      else
35097ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall        break;
35197ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall
35297ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall      LabelAndGotoScopes[SubStmt] = ParentScope;
35397ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall      SubStmt = Next;
35497ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall    }
35597ba481f3f45e5b63b4a354bfb471ce146b7de57John McCall
3565af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    // If this is a declstmt with a VLA definition, it defines a scope from here
3575af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    // to the end of the containing context.
3585af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    if (DeclStmt *DS = dyn_cast<DeclStmt>(SubStmt)) {
3596d97e5e4b7abdae710c2548b51f4ed0298e86d80Chris Lattner      // The decl statement creates a scope if any of the decls in it are VLAs
3606d97e5e4b7abdae710c2548b51f4ed0298e86d80Chris Lattner      // or have the cleanup attribute.
3615af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
36243dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor           I != E; ++I)
36343dec6bbde2d0a16c35978983761c8b7030c8e18Douglas Gregor        BuildScopeInformation(*I, ParentScope);
3645af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      continue;
3655af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    }
3665af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    // Disallow jumps into any part of an @try statement by pushing a scope and
3675af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    // walking all sub-stmts in that scope.
3685af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    if (ObjCAtTryStmt *AT = dyn_cast<ObjCAtTryStmt>(SubStmt)) {
3694e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      unsigned newParentScope;
3705af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      // Recursively walk the AST for the @try part.
371ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      Scopes.push_back(GotoScope(ParentScope,
372ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                 diag::note_protected_by_objc_try,
373ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                 diag::note_exits_objc_try,
3745af280ce21af061f96b5b5b752746871e364ba99Chris Lattner                                 AT->getAtTryLoc()));
3755af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      if (Stmt *TryPart = AT->getTryBody())
3764e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        BuildScopeInformation(TryPart, (newParentScope = Scopes.size()-1));
3775af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
3785af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      // Jump from the catch to the finally or try is not valid.
3798f5e3dd32e443768d9dbbad7191e123e6733750cDouglas Gregor      for (unsigned I = 0, N = AT->getNumCatchStmts(); I != N; ++I) {
3808f5e3dd32e443768d9dbbad7191e123e6733750cDouglas Gregor        ObjCAtCatchStmt *AC = AT->getCatchStmt(I);
3815af280ce21af061f96b5b5b752746871e364ba99Chris Lattner        Scopes.push_back(GotoScope(ParentScope,
3825af280ce21af061f96b5b5b752746871e364ba99Chris Lattner                                   diag::note_protected_by_objc_catch,
383ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                   diag::note_exits_objc_catch,
3845af280ce21af061f96b5b5b752746871e364ba99Chris Lattner                                   AC->getAtCatchLoc()));
3851eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump        // @catches are nested and it isn't
3864e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        BuildScopeInformation(AC->getCatchBody(),
3874e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                              (newParentScope = Scopes.size()-1));
3885af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      }
3891eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
3905af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      // Jump from the finally to the try or catch is not valid.
3915af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
3925af280ce21af061f96b5b5b752746871e364ba99Chris Lattner        Scopes.push_back(GotoScope(ParentScope,
3935af280ce21af061f96b5b5b752746871e364ba99Chris Lattner                                   diag::note_protected_by_objc_finally,
394ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                   diag::note_exits_objc_finally,
3955af280ce21af061f96b5b5b752746871e364ba99Chris Lattner                                   AF->getAtFinallyLoc()));
3964e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        BuildScopeInformation(AF, (newParentScope = Scopes.size()-1));
3975af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      }
3981eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
3995af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      continue;
4005af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    }
4014e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian
4024e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    unsigned newParentScope;
40346c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner    // Disallow jumps into the protected statement of an @synchronized, but
40446c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner    // allow jumps into the object expression it protects.
40546c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner    if (ObjCAtSynchronizedStmt *AS = dyn_cast<ObjCAtSynchronizedStmt>(SubStmt)){
40646c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner      // Recursively walk the AST for the @synchronized object expr, it is
40746c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner      // evaluated in the normal scope.
40846c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner      BuildScopeInformation(AS->getSynchExpr(), ParentScope);
4091eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
41046c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner      // Recursively walk the AST for the @synchronized part, protected by a new
41146c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner      // scope.
41246c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner      Scopes.push_back(GotoScope(ParentScope,
41346c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner                                 diag::note_protected_by_objc_synchronized,
414ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                 diag::note_exits_objc_synchronized,
41546c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner                                 AS->getAtSynchronizedLoc()));
4164e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      BuildScopeInformation(AS->getSynchBody(),
4174e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                            (newParentScope = Scopes.size()-1));
41846c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner      continue;
41946c3c4ba78766ac0f1c5ec631b424773e21f5271Chris Lattner    }
420972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl
421972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl    // Disallow jumps into any part of a C++ try statement. This is pretty
422972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl    // much the same as for Obj-C.
423972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl    if (CXXTryStmt *TS = dyn_cast<CXXTryStmt>(SubStmt)) {
424ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      Scopes.push_back(GotoScope(ParentScope,
425ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                 diag::note_protected_by_cxx_try,
426ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                 diag::note_exits_cxx_try,
427972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl                                 TS->getSourceRange().getBegin()));
428972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl      if (Stmt *TryBlock = TS->getTryBlock())
4294e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        BuildScopeInformation(TryBlock, (newParentScope = Scopes.size()-1));
430972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl
431972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl      // Jump from the catch into the try is not allowed either.
4321eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump      for (unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) {
433972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl        CXXCatchStmt *CS = TS->getHandler(I);
434972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl        Scopes.push_back(GotoScope(ParentScope,
435972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl                                   diag::note_protected_by_cxx_catch,
436ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                   diag::note_exits_cxx_catch,
437972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl                                   CS->getSourceRange().getBegin()));
4384e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        BuildScopeInformation(CS->getHandlerBlock(),
4394e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian                              (newParentScope = Scopes.size()-1));
440972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl      }
441972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl
442972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl      continue;
443972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl    }
444972041f45bdf8df7ea447221292d7827466ba94bSebastian Redl
445f85e193739c953358c865005855253af4f68a497John McCall    // Disallow jumps into the protected statement of an @autoreleasepool.
446f85e193739c953358c865005855253af4f68a497John McCall    if (ObjCAutoreleasePoolStmt *AS = dyn_cast<ObjCAutoreleasePoolStmt>(SubStmt)){
447f85e193739c953358c865005855253af4f68a497John McCall      // Recursively walk the AST for the @autoreleasepool part, protected by a new
448f85e193739c953358c865005855253af4f68a497John McCall      // scope.
449f85e193739c953358c865005855253af4f68a497John McCall      Scopes.push_back(GotoScope(ParentScope,
450f85e193739c953358c865005855253af4f68a497John McCall                                 diag::note_protected_by_objc_autoreleasepool,
451f85e193739c953358c865005855253af4f68a497John McCall                                 diag::note_exits_objc_autoreleasepool,
452f85e193739c953358c865005855253af4f68a497John McCall                                 AS->getAtLoc()));
4534e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian      BuildScopeInformation(AS->getSubStmt(), (newParentScope = Scopes.size()-1));
454f85e193739c953358c865005855253af4f68a497John McCall      continue;
455f85e193739c953358c865005855253af4f68a497John McCall    }
4564e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian
4574e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    if (const BlockExpr *BE = dyn_cast<BlockExpr>(SubStmt)) {
4584e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        const BlockDecl *BDecl = BE->getBlockDecl();
4594e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        for (BlockDecl::capture_const_iterator ci = BDecl->capture_begin(),
4604e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian             ce = BDecl->capture_end(); ci != ce; ++ci) {
4614e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian          VarDecl *variable = ci->getVariable();
4624e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian          BuildScopeInformation(variable, BDecl, ParentScope);
4634e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian        }
4644e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian    }
4654e7c7f2b78ac3930e45f00626ef6acf08b3f80caFariborz Jahanian
4665af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    // Recursively walk the AST.
4675af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    BuildScopeInformation(SubStmt, ParentScope);
4685af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  }
4695af280ce21af061f96b5b5b752746871e364ba99Chris Lattner}
4705af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
4715af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// VerifyJumps - Verify each element of the Jumps array to see if they are
4725af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// valid, emitting diagnostics if not.
4735af280ce21af061f96b5b5b752746871e364ba99Chris Lattnervoid JumpScopeChecker::VerifyJumps() {
4745af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  while (!Jumps.empty()) {
4755af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    Stmt *Jump = Jumps.pop_back_val();
4761eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
4771eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump    // With a goto,
4785af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    if (GotoStmt *GS = dyn_cast<GotoStmt>(Jump)) {
479ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner      CheckJump(GS, GS->getLabel()->getStmt(), GS->getGotoLoc(),
480c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet                diag::err_goto_into_protected_scope,
4810e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                diag::warn_goto_into_protected_scope,
4820e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                diag::warn_cxx98_compat_goto_into_protected_scope);
4835af280ce21af061f96b5b5b752746871e364ba99Chris Lattner      continue;
4845af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    }
4851eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
48695c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    // We only get indirect gotos here when they have a constant target.
48795c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    if (IndirectGotoStmt *IGS = dyn_cast<IndirectGotoStmt>(Jump)) {
488ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner      LabelDecl *Target = IGS->getConstantTarget();
489ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner      CheckJump(IGS, Target->getStmt(), IGS->getGotoLoc(),
4902e96511773c6a21291dfa5218eb8ba79f04b5318Francois Pichet                diag::err_goto_into_protected_scope,
4910e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                diag::warn_goto_into_protected_scope,
4920e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                diag::warn_cxx98_compat_goto_into_protected_scope);
49395c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall      continue;
49495c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall    }
49595c225de9fa3d79f70ef5008c0279580a7d9dcadJohn McCall
496ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    SwitchStmt *SS = cast<SwitchStmt>(Jump);
497ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    for (SwitchCase *SC = SS->getSwitchCaseList(); SC;
498ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall         SC = SC->getNextSwitchCase()) {
499ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      assert(LabelAndGotoScopes.count(SC) && "Case not visited?");
500ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      CheckJump(SS, SC, SC->getLocStart(),
5010e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                diag::err_switch_into_protected_scope, 0,
5020e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                diag::warn_cxx98_compat_switch_into_protected_scope);
5035af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    }
504ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  }
505ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall}
506ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
5075e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// VerifyIndirectJumps - Verify whether any possible indirect jump
5085e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// might cross a protection boundary.  Unlike direct jumps, indirect
5095e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// jumps count cleanups as protection boundaries:  since there's no
5105e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// way to know where the jump is going, we can't implicitly run the
5115e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// right cleanups the way we can with direct jumps.
5125e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall///
5135e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// Thus, an indirect jump is "trivial" if it bypasses no
5145e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// initializations and no teardowns.  More formally, an indirect jump
5155e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// from A to B is trivial if the path out from A to DCA(A,B) is
5165e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// trivial and the path in from DCA(A,B) to B is trivial, where
5175e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// DCA(A,B) is the deepest common ancestor of A and B.
5185e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// Jump-triviality is transitive but asymmetric.
519ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall///
520ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall/// A path in is trivial if none of the entered scopes have an InDiag.
521ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall/// A path out is trivial is none of the exited scopes have an OutDiag.
5225e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall///
5235e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// Under these definitions, this function checks that the indirect
5245e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// jump between A and B is trivial for every indirect goto statement A
5255e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// and every label B whose address was taken in the function.
526ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCallvoid JumpScopeChecker::VerifyIndirectJumps() {
527ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  if (IndirectJumps.empty()) return;
528ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
529ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  // If there aren't any address-of-label expressions in this function,
530ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  // complain about the first indirect goto.
531ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  if (IndirectJumpTargets.empty()) {
532ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    S.Diag(IndirectJumps[0]->getGotoLoc(),
533ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall           diag::err_indirect_goto_without_addrlabel);
534ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    return;
535ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  }
536ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
5375e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // Collect a single representative of every scope containing an
5385e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // indirect goto.  For most code bases, this substantially cuts
5395e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // down on the number of jump sites we'll have to consider later.
540ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  typedef std::pair<unsigned, IndirectGotoStmt*> JumpScope;
5415f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner  SmallVector<JumpScope, 32> JumpScopes;
542ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  {
543ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    llvm::DenseMap<unsigned, IndirectGotoStmt*> JumpScopesMap;
5445f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner    for (SmallVectorImpl<IndirectGotoStmt*>::iterator
545ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall           I = IndirectJumps.begin(), E = IndirectJumps.end(); I != E; ++I) {
546ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      IndirectGotoStmt *IG = *I;
547ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      assert(LabelAndGotoScopes.count(IG) &&
548ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall             "indirect jump didn't get added to scopes?");
549ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      unsigned IGScope = LabelAndGotoScopes[IG];
550ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      IndirectGotoStmt *&Entry = JumpScopesMap[IGScope];
551ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      if (!Entry) Entry = IG;
552ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    }
553ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    JumpScopes.reserve(JumpScopesMap.size());
554ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    for (llvm::DenseMap<unsigned, IndirectGotoStmt*>::iterator
555ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall           I = JumpScopesMap.begin(), E = JumpScopesMap.end(); I != E; ++I)
556ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      JumpScopes.push_back(*I);
557ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  }
558ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
5595e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // Collect a single representative of every scope containing a
5605e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // label whose address was taken somewhere in the function.
5615e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // For most code bases, there will be only one such scope.
562ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner  llvm::DenseMap<unsigned, LabelDecl*> TargetScopes;
5635f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner  for (SmallVectorImpl<LabelDecl*>::iterator
564ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall         I = IndirectJumpTargets.begin(), E = IndirectJumpTargets.end();
565ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall       I != E; ++I) {
566ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner    LabelDecl *TheLabel = *I;
567ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner    assert(LabelAndGotoScopes.count(TheLabel->getStmt()) &&
568ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall           "Referenced label didn't get added to scopes?");
569ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner    unsigned LabelScope = LabelAndGotoScopes[TheLabel->getStmt()];
570ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner    LabelDecl *&Target = TargetScopes[LabelScope];
571ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    if (!Target) Target = TheLabel;
572ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  }
573ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
5745e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // For each target scope, make sure it's trivially reachable from
5755e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // every scope containing a jump site.
5765e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  //
5775e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // A path between scopes always consists of exitting zero or more
5785e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // scopes, then entering zero or more scopes.  We build a set of
5795e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // of scopes S from which the target scope can be trivially
5805e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // entered, then verify that every jump scope can be trivially
5815e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // exitted to reach a scope in S.
582ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  llvm::BitVector Reachable(Scopes.size(), false);
583ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner  for (llvm::DenseMap<unsigned,LabelDecl*>::iterator
584ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall         TI = TargetScopes.begin(), TE = TargetScopes.end(); TI != TE; ++TI) {
585ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    unsigned TargetScope = TI->first;
586ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner    LabelDecl *TargetLabel = TI->second;
587ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
588ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    Reachable.reset();
589ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
590ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    // Mark all the enclosing scopes from which you can safely jump
5915e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall    // into the target scope.  'Min' will end up being the index of
5925e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall    // the shallowest such scope.
593ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    unsigned Min = TargetScope;
594ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    while (true) {
595ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      Reachable.set(Min);
596ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
597ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      // Don't go beyond the outermost scope.
598ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      if (Min == 0) break;
599ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
6005e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      // Stop if we can't trivially enter the current scope.
601ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      if (Scopes[Min].InDiag) break;
6025af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
603ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      Min = Scopes[Min].ParentScope;
6045af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    }
6055af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
606ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    // Walk through all the jump sites, checking that they can trivially
607ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall    // reach this label scope.
6085f9e272e632e951b1efe824cd16acb4d96077930Chris Lattner    for (SmallVectorImpl<JumpScope>::iterator
609ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall           I = JumpScopes.begin(), E = JumpScopes.end(); I != E; ++I) {
610ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      unsigned Scope = I->first;
611ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
612ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      // Walk out the "scope chain" for this scope, looking for a scope
6135e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      // we've marked reachable.  For well-formed code this amortizes
6145e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      // to O(JumpScopes.size() / Scopes.size()):  we only iterate
6155e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      // when we see something unmarked, and in well-formed code we
6165e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      // mark everything we iterate past.
617ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      bool IsReachable = false;
618ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      while (true) {
619ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        if (Reachable.test(Scope)) {
620ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall          // If we find something reachable, mark all the scopes we just
621ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall          // walked through as reachable.
622ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall          for (unsigned S = I->first; S != Scope; S = Scopes[S].ParentScope)
623ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall            Reachable.set(S);
624ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall          IsReachable = true;
625ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall          break;
626ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        }
627ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
628ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        // Don't walk out if we've reached the top-level scope or we've
629ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        // gotten shallower than the shallowest reachable scope.
630ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        if (Scope == 0 || Scope < Min) break;
631ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
632ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        // Don't walk out through an out-diagnostic.
633ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        if (Scopes[Scope].OutDiag) break;
634ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
635ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall        Scope = Scopes[Scope].ParentScope;
636ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      }
637ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
638ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      // Only diagnose if we didn't find something.
639ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      if (IsReachable) continue;
640ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
641ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall      DiagnoseIndirectJump(I->second, I->first, TargetLabel, TargetScope);
6425af280ce21af061f96b5b5b752746871e364ba99Chris Lattner    }
6435af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  }
6445af280ce21af061f96b5b5b752746871e364ba99Chris Lattner}
6455af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
6460e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith/// Return true if a particular error+note combination must be downgraded to a
6470e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith/// warning in Microsoft mode.
6480e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smithstatic bool IsMicrosoftJumpWarning(unsigned JumpDiag, unsigned InDiagNote) {
6490e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  return (JumpDiag == diag::err_goto_into_protected_scope &&
6500e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith         (InDiagNote == diag::note_protected_by_variable_init ||
6510e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith          InDiagNote == diag::note_protected_by_variable_nontriv_destructor));
6520e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith}
6530e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith
6540e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith/// Return true if a particular note should be downgraded to a compatibility
6550e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith/// warning in C++11 mode.
6560e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smithstatic bool IsCXX98CompatWarning(Sema &S, unsigned InDiagNote) {
6574e4d08403ca5cfd4d558fa2936215d3a4e5a528dDavid Blaikie  return S.getLangOpts().CPlusPlus0x &&
6580e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith         InDiagNote == diag::note_protected_by_variable_non_pod;
6590e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith}
6600e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith
6610e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith/// Produce primary diagnostic for an indirect jump statement.
6620e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smithstatic void DiagnoseIndirectJumpStmt(Sema &S, IndirectGotoStmt *Jump,
6630e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                                     LabelDecl *Target, bool &Diagnosed) {
6640e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  if (Diagnosed)
6650e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    return;
6660e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  S.Diag(Jump->getGotoLoc(), diag::err_indirect_goto_in_protected_scope);
6670e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target);
6680e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  Diagnosed = true;
6690e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith}
6700e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith
6710e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith/// Produce note diagnostics for a jump into a protected scope.
6724fe5be028b723fedc28bb33be96cde1ab2574ee6Bill Wendlingvoid JumpScopeChecker::NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes) {
6730e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  assert(!ToScopes.empty());
6740e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  for (unsigned I = 0, E = ToScopes.size(); I != E; ++I)
6750e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    if (Scopes[ToScopes[I]].InDiag)
6760e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith      S.Diag(Scopes[ToScopes[I]].Loc, Scopes[ToScopes[I]].InDiag);
6770e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith}
6780e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith
6795e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall/// Diagnose an indirect jump which is known to cross scopes.
680ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCallvoid JumpScopeChecker::DiagnoseIndirectJump(IndirectGotoStmt *Jump,
681ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                            unsigned JumpScope,
682ad8dcf4a9df0e24051dc31bf9e6f3cd138a34298Chris Lattner                                            LabelDecl *Target,
683ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall                                            unsigned TargetScope) {
684ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  assert(JumpScope != TargetScope);
685ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
6865e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  unsigned Common = GetDeepestCommonScope(JumpScope, TargetScope);
6870e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  bool Diagnosed = false;
6885e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall
6895e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // Walk out the scope chain until we reach the common ancestor.
6905e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  for (unsigned I = JumpScope; I != Common; I = Scopes[I].ParentScope)
6910e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    if (Scopes[I].OutDiag) {
6920e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith      DiagnoseIndirectJumpStmt(S, Jump, Target, Diagnosed);
6935e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      S.Diag(Scopes[I].Loc, Scopes[I].OutDiag);
6940e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    }
6950e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith
6960e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  SmallVector<unsigned, 10> ToScopesCXX98Compat;
697ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
698ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall  // Now walk into the scopes containing the label whose address was taken.
6995e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  for (unsigned I = TargetScope; I != Common; I = Scopes[I].ParentScope)
7000e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    if (IsCXX98CompatWarning(S, Scopes[I].InDiag))
7010e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith      ToScopesCXX98Compat.push_back(I);
7020e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    else if (Scopes[I].InDiag) {
7030e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith      DiagnoseIndirectJumpStmt(S, Jump, Target, Diagnosed);
7045e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall      S.Diag(Scopes[I].Loc, Scopes[I].InDiag);
7050e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    }
706ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
7070e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  // Diagnose this jump if it would be ill-formed in C++98.
7080e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  if (!Diagnosed && !ToScopesCXX98Compat.empty()) {
7090e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    S.Diag(Jump->getGotoLoc(),
7100e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith           diag::warn_cxx98_compat_indirect_goto_in_protected_scope);
7110e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target);
7120e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    NoteJumpIntoScopes(ToScopesCXX98Compat);
7130e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  }
714c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet}
715c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet
7165af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// CheckJump - Validate that the specified jump statement is valid: that it is
7175af280ce21af061f96b5b5b752746871e364ba99Chris Lattner/// jumping within or out of its current scope, not into a deeper one.
718c985b88efc9188845952ab524fe6d4717705257bFrancois Pichetvoid JumpScopeChecker::CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
7190e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                               unsigned JumpDiagError, unsigned JumpDiagWarning,
7200e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith                                 unsigned JumpDiagCXX98Compat) {
7215af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  assert(LabelAndGotoScopes.count(From) && "Jump didn't get added to scopes?");
7225af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  unsigned FromScope = LabelAndGotoScopes[From];
7235af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
7245af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  assert(LabelAndGotoScopes.count(To) && "Jump didn't get added to scopes?");
7255af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  unsigned ToScope = LabelAndGotoScopes[To];
7261eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
7275af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  // Common case: exactly the same scope, which is fine.
7285af280ce21af061f96b5b5b752746871e364ba99Chris Lattner  if (FromScope == ToScope) return;
7291eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
7305e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  unsigned CommonScope = GetDeepestCommonScope(FromScope, ToScope);
7311eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
7325e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // It's okay to jump out from a nested scope.
7335e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  if (CommonScope == ToScope) return;
7341eb4433ac451dc16f4133a88af2d002ac26c58efMike Stump
7355e2a7acbdc9e4aee4da54e1e2f560a78bf6fb3c1John McCall  // Pull out (and reverse) any scopes we might need to diagnose skipping.
7360e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  SmallVector<unsigned, 10> ToScopesCXX98Compat;
737c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  SmallVector<unsigned, 10> ToScopesError;
738c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  SmallVector<unsigned, 10> ToScopesWarning;
739c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  for (unsigned I = ToScope; I != CommonScope; I = Scopes[I].ParentScope) {
7404e4d08403ca5cfd4d558fa2936215d3a4e5a528dDavid Blaikie    if (S.getLangOpts().MicrosoftMode && JumpDiagWarning != 0 &&
741c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet        IsMicrosoftJumpWarning(JumpDiagError, Scopes[I].InDiag))
742c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet      ToScopesWarning.push_back(I);
7430e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    else if (IsCXX98CompatWarning(S, Scopes[I].InDiag))
7440e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith      ToScopesCXX98Compat.push_back(I);
745c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet    else if (Scopes[I].InDiag)
746c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet      ToScopesError.push_back(I);
747c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  }
748ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
749c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  // Handle warnings.
750c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  if (!ToScopesWarning.empty()) {
751c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet    S.Diag(DiagLoc, JumpDiagWarning);
7520e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    NoteJumpIntoScopes(ToScopesWarning);
753c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  }
754ddb0b4d5391d3e6bc9dcf93dc42310b20c96b6fcJohn McCall
755c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  // Handle errors.
756c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  if (!ToScopesError.empty()) {
757c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet    S.Diag(DiagLoc, JumpDiagError);
7580e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    NoteJumpIntoScopes(ToScopesError);
7590e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  }
7600e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith
7610e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  // Handle -Wc++98-compat warnings if the jump is well-formed.
7620e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith  if (ToScopesError.empty() && !ToScopesCXX98Compat.empty()) {
7630e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    S.Diag(DiagLoc, JumpDiagCXX98Compat);
7640e9e9814a7f8313c0c02b6afea71f0e4c411873eRichard Smith    NoteJumpIntoScopes(ToScopesCXX98Compat);
765c985b88efc9188845952ab524fe6d4717705257bFrancois Pichet  }
7665af280ce21af061f96b5b5b752746871e364ba99Chris Lattner}
7675af280ce21af061f96b5b5b752746871e364ba99Chris Lattner
7685af280ce21af061f96b5b5b752746871e364ba99Chris Lattnervoid Sema::DiagnoseInvalidJumps(Stmt *Body) {
7696490ae5003226cae28f980648948bea8b21a8638Douglas Gregor  (void)JumpScopeChecker(Body, *this);
7705af280ce21af061f96b5b5b752746871e364ba99Chris Lattner}
771