795 lines
31 KiB
C++
795 lines
31 KiB
C++
//===--- JumpDiagnostics.cpp - Protected scope jump analysis ------*- C++ -*-=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the JumpScopeChecker class, which is used to diagnose
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// jumps that enter a protected scope in an invalid way.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Sema/SemaInternal.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/ExprCXX.h"
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#include "clang/AST/StmtCXX.h"
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#include "clang/AST/StmtObjC.h"
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#include "llvm/ADT/BitVector.h"
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using namespace clang;
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namespace {
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/// JumpScopeChecker - This object is used by Sema to diagnose invalid jumps
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/// into VLA and other protected scopes. For example, this rejects:
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/// goto L;
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/// int a[n];
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/// L:
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///
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class JumpScopeChecker {
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Sema &S;
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/// GotoScope - This is a record that we use to keep track of all of the
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/// scopes that are introduced by VLAs and other things that scope jumps like
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/// gotos. This scope tree has nothing to do with the source scope tree,
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/// because you can have multiple VLA scopes per compound statement, and most
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/// compound statements don't introduce any scopes.
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struct GotoScope {
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/// ParentScope - The index in ScopeMap of the parent scope. This is 0 for
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/// the parent scope is the function body.
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unsigned ParentScope;
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/// InDiag - The note to emit if there is a jump into this scope.
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unsigned InDiag;
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/// OutDiag - The note to emit if there is an indirect jump out
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/// of this scope. Direct jumps always clean up their current scope
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/// in an orderly way.
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unsigned OutDiag;
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/// Loc - Location to emit the diagnostic.
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SourceLocation Loc;
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GotoScope(unsigned parentScope, unsigned InDiag, unsigned OutDiag,
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SourceLocation L)
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: ParentScope(parentScope), InDiag(InDiag), OutDiag(OutDiag), Loc(L) {}
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};
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SmallVector<GotoScope, 48> Scopes;
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llvm::DenseMap<Stmt*, unsigned> LabelAndGotoScopes;
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SmallVector<Stmt*, 16> Jumps;
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SmallVector<IndirectGotoStmt*, 4> IndirectJumps;
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SmallVector<LabelDecl*, 4> IndirectJumpTargets;
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public:
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JumpScopeChecker(Stmt *Body, Sema &S);
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private:
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void BuildScopeInformation(Decl *D, unsigned &ParentScope);
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void BuildScopeInformation(VarDecl *D, const BlockDecl *BDecl,
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unsigned &ParentScope);
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void BuildScopeInformation(Stmt *S, unsigned &origParentScope);
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void VerifyJumps();
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void VerifyIndirectJumps();
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void NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes);
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void DiagnoseIndirectJump(IndirectGotoStmt *IG, unsigned IGScope,
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LabelDecl *Target, unsigned TargetScope);
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void CheckJump(Stmt *From, Stmt *To, SourceLocation DiagLoc,
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unsigned JumpDiag, unsigned JumpDiagWarning,
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unsigned JumpDiagCXX98Compat);
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unsigned GetDeepestCommonScope(unsigned A, unsigned B);
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};
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} // end anonymous namespace
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JumpScopeChecker::JumpScopeChecker(Stmt *Body, Sema &s) : S(s) {
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// Add a scope entry for function scope.
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Scopes.push_back(GotoScope(~0U, ~0U, ~0U, SourceLocation()));
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// Build information for the top level compound statement, so that we have a
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// defined scope record for every "goto" and label.
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unsigned BodyParentScope = 0;
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BuildScopeInformation(Body, BodyParentScope);
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// Check that all jumps we saw are kosher.
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VerifyJumps();
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VerifyIndirectJumps();
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}
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/// GetDeepestCommonScope - Finds the innermost scope enclosing the
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/// two scopes.
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unsigned JumpScopeChecker::GetDeepestCommonScope(unsigned A, unsigned B) {
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while (A != B) {
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// Inner scopes are created after outer scopes and therefore have
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// higher indices.
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if (A < B) {
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assert(Scopes[B].ParentScope < B);
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B = Scopes[B].ParentScope;
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} else {
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assert(Scopes[A].ParentScope < A);
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A = Scopes[A].ParentScope;
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}
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}
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return A;
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}
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typedef std::pair<unsigned,unsigned> ScopePair;
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/// GetDiagForGotoScopeDecl - If this decl induces a new goto scope, return a
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/// diagnostic that should be emitted if control goes over it. If not, return 0.
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static ScopePair GetDiagForGotoScopeDecl(ASTContext &Context, const Decl *D) {
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if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
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unsigned InDiag = 0;
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if (VD->getType()->isVariablyModifiedType())
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InDiag = diag::note_protected_by_vla;
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if (VD->hasAttr<BlocksAttr>())
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return ScopePair(diag::note_protected_by___block,
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diag::note_exits___block);
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if (VD->hasAttr<CleanupAttr>())
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return ScopePair(diag::note_protected_by_cleanup,
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diag::note_exits_cleanup);
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if (Context.getLangOpts().ObjCAutoRefCount && VD->hasLocalStorage()) {
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switch (VD->getType().getObjCLifetime()) {
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case Qualifiers::OCL_None:
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case Qualifiers::OCL_ExplicitNone:
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case Qualifiers::OCL_Autoreleasing:
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break;
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case Qualifiers::OCL_Strong:
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case Qualifiers::OCL_Weak:
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return ScopePair(diag::note_protected_by_objc_ownership,
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diag::note_exits_objc_ownership);
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}
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}
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if (Context.getLangOpts().CPlusPlus && VD->hasLocalStorage()) {
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// C++11 [stmt.dcl]p3:
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// A program that jumps from a point where a variable with automatic
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// storage duration is not in scope to a point where it is in scope
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// is ill-formed unless the variable has scalar type, class type with
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// a trivial default constructor and a trivial destructor, a
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// cv-qualified version of one of these types, or an array of one of
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// the preceding types and is declared without an initializer.
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// C++03 [stmt.dcl.p3:
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// A program that jumps from a point where a local variable
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// with automatic storage duration is not in scope to a point
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// where it is in scope is ill-formed unless the variable has
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// POD type and is declared without an initializer.
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const Expr *Init = VD->getInit();
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if (!Init)
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return ScopePair(InDiag, 0);
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const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init);
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if (EWC)
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Init = EWC->getSubExpr();
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const MaterializeTemporaryExpr *M = NULL;
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Init = Init->findMaterializedTemporary(M);
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SmallVector<const Expr *, 2> CommaLHSs;
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SmallVector<SubobjectAdjustment, 2> Adjustments;
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Init = Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
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QualType QT = Init->getType();
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if (QT.isNull())
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return ScopePair(diag::note_protected_by_variable_init, 0);
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const Type *T = QT.getTypePtr();
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if (T->isArrayType())
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T = T->getBaseElementTypeUnsafe();
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const CXXRecordDecl *Record = T->getAsCXXRecordDecl();
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if (!Record)
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return ScopePair(diag::note_protected_by_variable_init, 0);
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// If we need to call a non trivial destructor for this variable,
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// record an out diagnostic.
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unsigned OutDiag = 0;
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if (!Init->isGLValue() && !Record->hasTrivialDestructor())
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OutDiag = diag::note_exits_dtor;
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if (const CXXConstructExpr *cce = dyn_cast<CXXConstructExpr>(Init)) {
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const CXXConstructorDecl *ctor = cce->getConstructor();
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// For a variable declared without an initializer, we will have
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// call-style initialization and the initializer will be the
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// CXXConstructExpr with no intervening nodes.
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if (ctor->isTrivial() && ctor->isDefaultConstructor() &&
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VD->getInit() == Init && VD->getInitStyle() == VarDecl::CallInit) {
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if (OutDiag)
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InDiag = diag::note_protected_by_variable_nontriv_destructor;
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else if (!Record->isPOD())
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InDiag = diag::note_protected_by_variable_non_pod;
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return ScopePair(InDiag, OutDiag);
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}
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}
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return ScopePair(diag::note_protected_by_variable_init, OutDiag);
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}
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return ScopePair(InDiag, 0);
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}
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if (const TypedefDecl *TD = dyn_cast<TypedefDecl>(D)) {
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if (TD->getUnderlyingType()->isVariablyModifiedType())
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return ScopePair(diag::note_protected_by_vla_typedef, 0);
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}
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if (const TypeAliasDecl *TD = dyn_cast<TypeAliasDecl>(D)) {
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if (TD->getUnderlyingType()->isVariablyModifiedType())
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return ScopePair(diag::note_protected_by_vla_type_alias, 0);
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}
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return ScopePair(0U, 0U);
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}
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/// \brief Build scope information for a declaration that is part of a DeclStmt.
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void JumpScopeChecker::BuildScopeInformation(Decl *D, unsigned &ParentScope) {
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// If this decl causes a new scope, push and switch to it.
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std::pair<unsigned,unsigned> Diags = GetDiagForGotoScopeDecl(S.Context, D);
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if (Diags.first || Diags.second) {
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Scopes.push_back(GotoScope(ParentScope, Diags.first, Diags.second,
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D->getLocation()));
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ParentScope = Scopes.size()-1;
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}
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// If the decl has an initializer, walk it with the potentially new
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// scope we just installed.
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if (VarDecl *VD = dyn_cast<VarDecl>(D))
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if (Expr *Init = VD->getInit())
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BuildScopeInformation(Init, ParentScope);
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}
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/// \brief Build scope information for a captured block literal variables.
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void JumpScopeChecker::BuildScopeInformation(VarDecl *D,
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const BlockDecl *BDecl,
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unsigned &ParentScope) {
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// exclude captured __block variables; there's no destructor
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// associated with the block literal for them.
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if (D->hasAttr<BlocksAttr>())
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return;
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QualType T = D->getType();
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QualType::DestructionKind destructKind = T.isDestructedType();
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if (destructKind != QualType::DK_none) {
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std::pair<unsigned,unsigned> Diags;
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switch (destructKind) {
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case QualType::DK_cxx_destructor:
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Diags = ScopePair(diag::note_enters_block_captures_cxx_obj,
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diag::note_exits_block_captures_cxx_obj);
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break;
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case QualType::DK_objc_strong_lifetime:
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Diags = ScopePair(diag::note_enters_block_captures_strong,
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diag::note_exits_block_captures_strong);
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break;
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case QualType::DK_objc_weak_lifetime:
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Diags = ScopePair(diag::note_enters_block_captures_weak,
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diag::note_exits_block_captures_weak);
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break;
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case QualType::DK_none:
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llvm_unreachable("non-lifetime captured variable");
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}
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SourceLocation Loc = D->getLocation();
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if (Loc.isInvalid())
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Loc = BDecl->getLocation();
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Scopes.push_back(GotoScope(ParentScope,
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Diags.first, Diags.second, Loc));
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ParentScope = Scopes.size()-1;
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}
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}
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/// BuildScopeInformation - The statements from CI to CE are known to form a
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/// coherent VLA scope with a specified parent node. Walk through the
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/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
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/// walking the AST as needed.
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void JumpScopeChecker::BuildScopeInformation(Stmt *S, unsigned &origParentScope) {
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// If this is a statement, rather than an expression, scopes within it don't
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// propagate out into the enclosing scope. Otherwise we have to worry
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// about block literals, which have the lifetime of their enclosing statement.
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unsigned independentParentScope = origParentScope;
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unsigned &ParentScope = ((isa<Expr>(S) && !isa<StmtExpr>(S))
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? origParentScope : independentParentScope);
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bool SkipFirstSubStmt = false;
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// If we found a label, remember that it is in ParentScope scope.
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switch (S->getStmtClass()) {
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case Stmt::AddrLabelExprClass:
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IndirectJumpTargets.push_back(cast<AddrLabelExpr>(S)->getLabel());
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break;
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case Stmt::IndirectGotoStmtClass:
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// "goto *&&lbl;" is a special case which we treat as equivalent
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// to a normal goto. In addition, we don't calculate scope in the
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// operand (to avoid recording the address-of-label use), which
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// works only because of the restricted set of expressions which
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// we detect as constant targets.
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if (cast<IndirectGotoStmt>(S)->getConstantTarget()) {
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LabelAndGotoScopes[S] = ParentScope;
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Jumps.push_back(S);
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return;
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}
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LabelAndGotoScopes[S] = ParentScope;
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IndirectJumps.push_back(cast<IndirectGotoStmt>(S));
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break;
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case Stmt::SwitchStmtClass:
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// Evaluate the condition variable before entering the scope of the switch
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// statement.
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if (VarDecl *Var = cast<SwitchStmt>(S)->getConditionVariable()) {
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BuildScopeInformation(Var, ParentScope);
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SkipFirstSubStmt = true;
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}
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// Fall through
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case Stmt::GotoStmtClass:
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// Remember both what scope a goto is in as well as the fact that we have
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// it. This makes the second scan not have to walk the AST again.
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LabelAndGotoScopes[S] = ParentScope;
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Jumps.push_back(S);
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break;
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case Stmt::CXXTryStmtClass: {
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CXXTryStmt *TS = cast<CXXTryStmt>(S);
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unsigned newParentScope;
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Scopes.push_back(GotoScope(ParentScope,
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diag::note_protected_by_cxx_try,
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diag::note_exits_cxx_try,
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TS->getSourceRange().getBegin()));
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if (Stmt *TryBlock = TS->getTryBlock())
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BuildScopeInformation(TryBlock, (newParentScope = Scopes.size()-1));
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// Jump from the catch into the try is not allowed either.
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for (unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) {
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CXXCatchStmt *CS = TS->getHandler(I);
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Scopes.push_back(GotoScope(ParentScope,
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diag::note_protected_by_cxx_catch,
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diag::note_exits_cxx_catch,
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CS->getSourceRange().getBegin()));
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BuildScopeInformation(CS->getHandlerBlock(),
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(newParentScope = Scopes.size()-1));
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}
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return;
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}
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default:
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break;
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}
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for (Stmt::child_range CI = S->children(); CI; ++CI) {
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if (SkipFirstSubStmt) {
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SkipFirstSubStmt = false;
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continue;
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}
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Stmt *SubStmt = *CI;
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if (SubStmt == 0) continue;
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// Cases, labels, and defaults aren't "scope parents". It's also
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// important to handle these iteratively instead of recursively in
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// order to avoid blowing out the stack.
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while (true) {
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Stmt *Next;
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if (CaseStmt *CS = dyn_cast<CaseStmt>(SubStmt))
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Next = CS->getSubStmt();
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else if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SubStmt))
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Next = DS->getSubStmt();
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else if (LabelStmt *LS = dyn_cast<LabelStmt>(SubStmt))
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Next = LS->getSubStmt();
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else
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break;
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LabelAndGotoScopes[SubStmt] = ParentScope;
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SubStmt = Next;
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}
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// If this is a declstmt with a VLA definition, it defines a scope from here
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// to the end of the containing context.
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if (DeclStmt *DS = dyn_cast<DeclStmt>(SubStmt)) {
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// The decl statement creates a scope if any of the decls in it are VLAs
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// or have the cleanup attribute.
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for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
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I != E; ++I)
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BuildScopeInformation(*I, ParentScope);
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continue;
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}
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// Disallow jumps into any part of an @try statement by pushing a scope and
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// walking all sub-stmts in that scope.
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if (ObjCAtTryStmt *AT = dyn_cast<ObjCAtTryStmt>(SubStmt)) {
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unsigned newParentScope;
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// Recursively walk the AST for the @try part.
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Scopes.push_back(GotoScope(ParentScope,
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diag::note_protected_by_objc_try,
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diag::note_exits_objc_try,
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AT->getAtTryLoc()));
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if (Stmt *TryPart = AT->getTryBody())
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BuildScopeInformation(TryPart, (newParentScope = Scopes.size()-1));
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// Jump from the catch to the finally or try is not valid.
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for (unsigned I = 0, N = AT->getNumCatchStmts(); I != N; ++I) {
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ObjCAtCatchStmt *AC = AT->getCatchStmt(I);
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Scopes.push_back(GotoScope(ParentScope,
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diag::note_protected_by_objc_catch,
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diag::note_exits_objc_catch,
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AC->getAtCatchLoc()));
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// @catches are nested and it isn't
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BuildScopeInformation(AC->getCatchBody(),
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(newParentScope = Scopes.size()-1));
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}
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// Jump from the finally to the try or catch is not valid.
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if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
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Scopes.push_back(GotoScope(ParentScope,
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diag::note_protected_by_objc_finally,
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diag::note_exits_objc_finally,
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AF->getAtFinallyLoc()));
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BuildScopeInformation(AF, (newParentScope = Scopes.size()-1));
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}
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continue;
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}
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unsigned newParentScope;
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// Disallow jumps into the protected statement of an @synchronized, but
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// allow jumps into the object expression it protects.
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if (ObjCAtSynchronizedStmt *AS = dyn_cast<ObjCAtSynchronizedStmt>(SubStmt)){
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// Recursively walk the AST for the @synchronized object expr, it is
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// evaluated in the normal scope.
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BuildScopeInformation(AS->getSynchExpr(), ParentScope);
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// Recursively walk the AST for the @synchronized part, protected by a new
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// scope.
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Scopes.push_back(GotoScope(ParentScope,
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diag::note_protected_by_objc_synchronized,
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diag::note_exits_objc_synchronized,
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AS->getAtSynchronizedLoc()));
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BuildScopeInformation(AS->getSynchBody(),
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(newParentScope = Scopes.size()-1));
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continue;
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}
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// Disallow jumps into the protected statement of an @autoreleasepool.
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if (ObjCAutoreleasePoolStmt *AS = dyn_cast<ObjCAutoreleasePoolStmt>(SubStmt)){
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// Recursively walk the AST for the @autoreleasepool part, protected by a new
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// scope.
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Scopes.push_back(GotoScope(ParentScope,
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diag::note_protected_by_objc_autoreleasepool,
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diag::note_exits_objc_autoreleasepool,
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AS->getAtLoc()));
|
|
BuildScopeInformation(AS->getSubStmt(), (newParentScope = Scopes.size()-1));
|
|
continue;
|
|
}
|
|
|
|
// 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.
|
|
if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(SubStmt)) {
|
|
for (unsigned i = 0, e = EWC->getNumObjects(); i != e; ++i) {
|
|
const BlockDecl *BDecl = EWC->getObject(i);
|
|
for (BlockDecl::capture_const_iterator ci = BDecl->capture_begin(),
|
|
ce = BDecl->capture_end(); ci != ce; ++ci) {
|
|
VarDecl *variable = ci->getVariable();
|
|
BuildScopeInformation(variable, BDecl, ParentScope);
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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)) {
|
|
CheckJump(GS, GS->getLabel()->getStmt(), GS->getGotoLoc(),
|
|
diag::err_goto_into_protected_scope,
|
|
diag::warn_goto_into_protected_scope,
|
|
diag::warn_cxx98_compat_goto_into_protected_scope);
|
|
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::warn_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()) {
|
|
assert(LabelAndGotoScopes.count(SC) && "Case not visited?");
|
|
SourceLocation Loc;
|
|
if (CaseStmt *CS = dyn_cast<CaseStmt>(SC))
|
|
Loc = CS->getLocStart();
|
|
else if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC))
|
|
Loc = DS->getLocStart();
|
|
else
|
|
Loc = SC->getLocStart();
|
|
CheckJump(SS, SC, Loc, diag::err_switch_into_protected_scope, 0,
|
|
diag::warn_cxx98_compat_switch_into_protected_scope);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// VerifyIndirectJumps - Verify whether any possible indirect jump
|
|
/// might cross a protection boundary. Unlike direct jumps, indirect
|
|
/// 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 jump is "trivial" if it bypasses no
|
|
/// initializations and no teardowns. More formally, an indirect 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::VerifyIndirectJumps() {
|
|
if (IndirectJumps.empty()) return;
|
|
|
|
// If there aren't any address-of-label expressions in this function,
|
|
// complain about the first indirect goto.
|
|
if (IndirectJumpTargets.empty()) {
|
|
S.Diag(IndirectJumps[0]->getGotoLoc(),
|
|
diag::err_indirect_goto_without_addrlabel);
|
|
return;
|
|
}
|
|
|
|
// Collect a single representative of every scope containing an
|
|
// indirect 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, IndirectGotoStmt*> JumpScope;
|
|
SmallVector<JumpScope, 32> JumpScopes;
|
|
{
|
|
llvm::DenseMap<unsigned, IndirectGotoStmt*> JumpScopesMap;
|
|
for (SmallVectorImpl<IndirectGotoStmt*>::iterator
|
|
I = IndirectJumps.begin(), E = IndirectJumps.end(); I != E; ++I) {
|
|
IndirectGotoStmt *IG = *I;
|
|
assert(LabelAndGotoScopes.count(IG) &&
|
|
"indirect jump didn't get added to scopes?");
|
|
unsigned IGScope = LabelAndGotoScopes[IG];
|
|
IndirectGotoStmt *&Entry = JumpScopesMap[IGScope];
|
|
if (!Entry) Entry = IG;
|
|
}
|
|
JumpScopes.reserve(JumpScopesMap.size());
|
|
for (llvm::DenseMap<unsigned, IndirectGotoStmt*>::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 = IndirectJumpTargets.begin(), E = IndirectJumpTargets.end();
|
|
I != E; ++I) {
|
|
LabelDecl *TheLabel = *I;
|
|
assert(LabelAndGotoScopes.count(TheLabel->getStmt()) &&
|
|
"Referenced label didn't get added to scopes?");
|
|
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;
|
|
|
|
DiagnoseIndirectJump(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 DiagnoseIndirectJumpStmt(Sema &S, IndirectGotoStmt *Jump,
|
|
LabelDecl *Target, bool &Diagnosed) {
|
|
if (Diagnosed)
|
|
return;
|
|
S.Diag(Jump->getGotoLoc(), diag::err_indirect_goto_in_protected_scope);
|
|
S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target);
|
|
Diagnosed = true;
|
|
}
|
|
|
|
/// Produce note diagnostics for a jump into a protected scope.
|
|
void JumpScopeChecker::NoteJumpIntoScopes(ArrayRef<unsigned> ToScopes) {
|
|
assert(!ToScopes.empty());
|
|
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::DiagnoseIndirectJump(IndirectGotoStmt *Jump,
|
|
unsigned JumpScope,
|
|
LabelDecl *Target,
|
|
unsigned TargetScope) {
|
|
assert(JumpScope != TargetScope);
|
|
|
|
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) {
|
|
DiagnoseIndirectJumpStmt(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) {
|
|
DiagnoseIndirectJumpStmt(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()) {
|
|
S.Diag(Jump->getGotoLoc(),
|
|
diag::warn_cxx98_compat_indirect_goto_in_protected_scope);
|
|
S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target);
|
|
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) {
|
|
assert(LabelAndGotoScopes.count(From) && "Jump didn't get added to scopes?");
|
|
unsigned FromScope = LabelAndGotoScopes[From];
|
|
|
|
assert(LabelAndGotoScopes.count(To) && "Jump didn't get added to scopes?");
|
|
unsigned ToScope = LabelAndGotoScopes[To];
|
|
|
|
// Common case: exactly the same scope, which is fine.
|
|
if (FromScope == ToScope) return;
|
|
|
|
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().MicrosoftMode && 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);
|
|
}
|
|
|
|
// 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 Sema::DiagnoseInvalidJumps(Stmt *Body) {
|
|
(void)JumpScopeChecker(Body, *this);
|
|
}
|