move jump scope checking and related code out into its own file, SemaDecl.cpp is
already too large.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69505 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 2f57a49..887c86c 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2905,272 +2905,6 @@
return DeclPtrTy::make(FD);
}
-/// JumpScopeChecker - This object is used by Sema to diagnose invalid jumps
-/// into VLA and other protected scopes. For example, this rejects:
-/// goto L;
-/// int a[n];
-/// L:
-///
-namespace {
-class JumpScopeChecker {
- Sema &S;
-
- /// GotoScope - This is a record that we use to keep track of all of the scopes
- /// that are introduced by VLAs and other things that scope jumps like gotos.
- /// This scope tree has nothing to do with the source scope tree, because you
- /// can have multiple VLA scopes per compound statement, and most compound
- /// statements don't introduce any scopes.
- struct GotoScope {
- /// ParentScope - The index in ScopeMap of the parent scope. This is 0 for
- /// the parent scope is the function body.
- unsigned ParentScope;
-
- /// Diag - The diagnostic to emit if there is a jump into this scope.
- unsigned Diag;
-
- /// Loc - Location to emit the diagnostic.
- SourceLocation Loc;
-
- GotoScope(unsigned parentScope, unsigned diag, SourceLocation L)
- : ParentScope(parentScope), Diag(diag), Loc(L) {}
- };
-
- llvm::SmallVector<GotoScope, 48> Scopes;
- llvm::DenseMap<Stmt*, unsigned> LabelAndGotoScopes;
- llvm::SmallVector<Stmt*, 16> Jumps;
-public:
- JumpScopeChecker(CompoundStmt *Body, Sema &S);
-private:
- void BuildScopeInformation(Stmt *S, unsigned ParentScope);
- void VerifyJumps();
- void CheckJump(Stmt *From, Stmt *To,
- SourceLocation DiagLoc, unsigned JumpDiag);
-};
-} // end anonymous namespace
-
-
-JumpScopeChecker::JumpScopeChecker(CompoundStmt *Body, Sema &s) : S(s) {
- // Add a scope entry for function scope.
- Scopes.push_back(GotoScope(~0U, ~0U, SourceLocation()));
-
- // Build information for the top level compound statement, so that we have a
- // defined scope record for every "goto" and label.
- BuildScopeInformation(Body, 0);
-
- // Check that all jumps we saw are kosher.
- VerifyJumps();
-}
-
-/// GetDiagForGotoScopeDecl - If this decl induces a new goto scope, return a
-/// diagnostic that should be emitted if control goes over it. If not, return 0.
-static unsigned GetDiagForGotoScopeDecl(const Decl *D) {
- if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
- if (VD->getType()->isVariablyModifiedType())
- return diag::note_protected_by_vla;
- if (VD->hasAttr<CleanupAttr>())
- return diag::note_protected_by_cleanup;
- } else if (const TypedefDecl *TD = dyn_cast<TypedefDecl>(D)) {
- if (TD->getUnderlyingType()->isVariablyModifiedType())
- return diag::note_protected_by_vla_typedef;
- }
-
- return 0;
-}
-
-
-/// BuildScopeInformation - The statements from CI to CE are known to form a
-/// coherent VLA scope with a specified parent node. Walk through the
-/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
-/// walking the AST as needed.
-void JumpScopeChecker::BuildScopeInformation(Stmt *S, unsigned ParentScope) {
-
- // If we found a label, remember that it is in ParentScope scope.
- if (isa<LabelStmt>(S) || isa<DefaultStmt>(S) || isa<CaseStmt>(S)) {
- LabelAndGotoScopes[S] = ParentScope;
- } else if (isa<GotoStmt>(S) || isa<SwitchStmt>(S) ||
- isa<IndirectGotoStmt>(S) || isa<AddrLabelExpr>(S)) {
- // Remember both what scope a goto is in as well as the fact that we have
- // it. This makes the second scan not have to walk the AST again.
- LabelAndGotoScopes[S] = ParentScope;
- Jumps.push_back(S);
- }
-
- for (Stmt::child_iterator CI = S->child_begin(), E = S->child_end(); CI != E;
- ++CI) {
- Stmt *SubStmt = *CI;
- if (SubStmt == 0) continue;
-
- // FIXME: diagnose jumps past initialization: required in C++, warning in C.
- // goto L; int X = 4; L: ;
- // FIXME: what about jumps into C++ catch blocks, what are the rules?
-
- // If this is a declstmt with a VLA definition, it defines a scope from here
- // to the end of the containing context.
- if (DeclStmt *DS = dyn_cast<DeclStmt>(SubStmt)) {
- // The decl statement creates a scope if any of the decls in it are VLAs or
- // have the cleanup attribute.
- for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
- I != E; ++I) {
- // If this decl causes a new scope, push and switch to it.
- if (unsigned Diag = GetDiagForGotoScopeDecl(*I)) {
- Scopes.push_back(GotoScope(ParentScope, Diag, (*I)->getLocation()));
- ParentScope = Scopes.size()-1;
- }
-
- // If the decl has an initializer, walk it with the potentially new
- // scope we just installed.
- if (VarDecl *VD = dyn_cast<VarDecl>(*I))
- if (Expr *Init = VD->getInit())
- BuildScopeInformation(Init, ParentScope);
- }
- continue;
- }
-
- // Disallow jumps into any part of an @try statement by pushing a scope and
- // walking all sub-stmts in that scope.
- if (ObjCAtTryStmt *AT = dyn_cast<ObjCAtTryStmt>(SubStmt)) {
- // Recursively walk the AST for the @try part.
- Scopes.push_back(GotoScope(ParentScope,diag::note_protected_by_objc_try,
- AT->getAtTryLoc()));
- if (Stmt *TryPart = AT->getTryBody())
- BuildScopeInformation(TryPart, Scopes.size()-1);
-
- // Jump from the catch to the finally or try is not valid.
- for (ObjCAtCatchStmt *AC = AT->getCatchStmts(); AC;
- AC = AC->getNextCatchStmt()) {
- Scopes.push_back(GotoScope(ParentScope,
- diag::note_protected_by_objc_catch,
- AC->getAtCatchLoc()));
- // @catches are nested and it isn't
- BuildScopeInformation(AC->getCatchBody(), Scopes.size()-1);
- }
-
- // Jump from the finally to the try or catch is not valid.
- if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
- Scopes.push_back(GotoScope(ParentScope,
- diag::note_protected_by_objc_finally,
- AF->getAtFinallyLoc()));
- BuildScopeInformation(AF, Scopes.size()-1);
- }
-
- continue;
- }
-
- // Recursively walk the AST.
- BuildScopeInformation(SubStmt, ParentScope);
- }
-}
-
-void JumpScopeChecker::VerifyJumps() {
- while (!Jumps.empty()) {
- Stmt *Jump = Jumps.pop_back_val();
-
- if (GotoStmt *GS = dyn_cast<GotoStmt>(Jump)) {
- CheckJump(GS, GS->getLabel(), GS->getGotoLoc(),
- diag::err_goto_into_protected_scope);
- continue;
- }
-
- if (SwitchStmt *SS = dyn_cast<SwitchStmt>(Jump)) {
- for (SwitchCase *SC = SS->getSwitchCaseList(); SC;
- SC = SC->getNextSwitchCase()) {
- assert(LabelAndGotoScopes.count(SC) && "Case not visited?");
- CheckJump(SS, SC, SC->getLocStart(),
- diag::err_switch_into_protected_scope);
- }
- continue;
- }
-
-
- unsigned DiagnosticScope;
-
- // We don't know where an indirect goto goes, require that it be at the
- // top level of scoping.
- if (IndirectGotoStmt *IG = dyn_cast<IndirectGotoStmt>(Jump)) {
- assert(LabelAndGotoScopes.count(Jump) &&
- "Jump didn't get added to scopes?");
- unsigned GotoScope = LabelAndGotoScopes[IG];
- if (GotoScope == 0) continue; // indirect jump is ok.
- S.Diag(IG->getGotoLoc(), diag::err_indirect_goto_in_protected_scope);
- DiagnosticScope = GotoScope;
- } else {
- // We model &&Label as a jump for purposes of scope tracking. We actually
- // don't care *where* the address of label is, but we require the *label
- // itself* to be in scope 0. If it is nested inside of a VLA scope, then
- // it is possible for an indirect goto to illegally enter the VLA scope by
- // indirectly jumping to the label.
- assert(isa<AddrLabelExpr>(Jump) && "Unknown jump type");
- LabelStmt *TheLabel = cast<AddrLabelExpr>(Jump)->getLabel();
-
- assert(LabelAndGotoScopes.count(TheLabel) &&
- "Referenced label didn't get added to scopes?");
- unsigned LabelScope = LabelAndGotoScopes[TheLabel];
- if (LabelScope == 0) continue; // Addr of label is ok.
-
- S.Diag(Jump->getLocStart(), diag::err_addr_of_label_in_protected_scope);
- DiagnosticScope = LabelScope;
- }
-
- // Report all the things that would be skipped over by this &&label or
- // indirect goto.
- while (DiagnosticScope != 0) {
- S.Diag(Scopes[DiagnosticScope].Loc, Scopes[DiagnosticScope].Diag);
- DiagnosticScope = Scopes[DiagnosticScope].ParentScope;
- }
- }
-}
-
-/// 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 JumpDiag) {
- 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;
-
- // The only valid mismatch jump case happens when the jump is more deeply
- // nested inside the jump target. Do a quick scan to see if the jump is valid
- // because valid code is more common than invalid code.
- unsigned TestScope = Scopes[FromScope].ParentScope;
- while (TestScope != ~0U) {
- // If we found the jump target, then we're jumping out of our current scope,
- // which is perfectly fine.
- if (TestScope == ToScope) return;
-
- // Otherwise, scan up the hierarchy.
- TestScope = Scopes[TestScope].ParentScope;
- }
-
- // If we get here, then we know we have invalid code. Diagnose the bad jump,
- // and then emit a note at each VLA being jumped out of.
- S.Diag(DiagLoc, JumpDiag);
-
- // Eliminate the common prefix of the jump and the target. Start by
- // linearizing both scopes, reversing them as we go.
- std::vector<unsigned> FromScopes, ToScopes;
- for (TestScope = FromScope; TestScope != ~0U;
- TestScope = Scopes[TestScope].ParentScope)
- FromScopes.push_back(TestScope);
- for (TestScope = ToScope; TestScope != ~0U;
- TestScope = Scopes[TestScope].ParentScope)
- ToScopes.push_back(TestScope);
-
- // Remove any common entries (such as the top-level function scope).
- while (!FromScopes.empty() && FromScopes.back() == ToScopes.back()) {
- FromScopes.pop_back();
- ToScopes.pop_back();
- }
-
- // Emit diagnostics for whatever is left in ToScopes.
- for (unsigned i = 0, e = ToScopes.size(); i != e; ++i)
- S.Diag(Scopes[ToScopes[i]].Loc, Scopes[ToScopes[i]].Diag);
-}
-
Sema::DeclPtrTy Sema::ActOnFinishFunctionBody(DeclPtrTy D, StmtArg BodyArg) {
Decl *dcl = D.getAs<Decl>();
@@ -3230,7 +2964,7 @@
if (!Body) return D;
// Verify that that gotos and switch cases don't jump into scopes illegally.
- JumpScopeChecker(Body, *this);
+ DiagnoseInvalidJumps(Body);
return D;
}