r300722 - [Sema][ObjC] Disallow jumping into ObjC fast enumeration loops.

[Akira Hatanaka via cfe-commits]

Author: ahatanak
Date: Wed Apr 19 12:54:08 2017
New Revision: 300722

URL: http://llvm.org/viewvc/llvm-project?rev=300722&view=rev
Log:
[Sema][ObjC] Disallow jumping into ObjC fast enumeration loops.

rdar://problem/31635406

Differential Revision: https://reviews.llvm.org/D32187

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/JumpDiagnostics.cpp
    cfe/trunk/lib/Sema/SemaStmt.cpp
    cfe/trunk/test/SemaObjC/foreach.m

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=300722&r1=300721&r2=300722&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Apr 19 12:54:08 2017
@@ -5000,6 +5000,8 @@ def note_protected_by_if_available : Not
   "jump enters controlled statement of if available">;
 def note_protected_by_vla : Note<
   "jump bypasses initialization of variable length array">;
+def note_protected_by_objc_fast_enumeration : Note<
+  "jump enters Objective-C fast enumeration loop">;
 def note_protected_by_objc_try : Note<
   "jump bypasses initialization of @try block">;
 def note_protected_by_objc_catch : Note<

Modified: cfe/trunk/lib/Sema/JumpDiagnostics.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/JumpDiagnostics.cpp?rev=300722&r1=300721&r2=300722&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/JumpDiagnostics.cpp (original)
+++ cfe/trunk/lib/Sema/JumpDiagnostics.cpp Wed Apr 19 12:54:08 2017
@@ -287,6 +287,15 @@ void JumpScopeChecker::BuildScopeInforma
     IndirectJumpTargets.push_back(cast<AddrLabelExpr>(S)->getLabel());
     break;
 
+  case Stmt::ObjCForCollectionStmtClass: {
+    auto *CS = cast<ObjCForCollectionStmt>(S);
+    unsigned Diag = diag::note_protected_by_objc_fast_enumeration;
+    unsigned NewParentScope = Scopes.size();
+    Scopes.push_back(GotoScope(ParentScope, Diag, 0, S->getLocStart()));
+    BuildScopeInformation(CS->getBody(), NewParentScope);
+    return;
+  }
+
   case Stmt::IndirectGotoStmtClass:
     // "goto *&&lbl;" is a special case which we treat as equivalent
     // to a normal goto.  In addition, we don't calculate scope in the

Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=300722&r1=300721&r2=300722&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmt.cpp Wed Apr 19 12:54:08 2017
@@ -1783,6 +1783,7 @@ StmtResult
 Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
                                  Stmt *First, Expr *collection,
                                  SourceLocation RParenLoc) {
+  getCurFunction()->setHasBranchProtectedScope();
 
   ExprResult CollectionExprResult =
     CheckObjCForCollectionOperand(ForLoc, collection);

Modified: cfe/trunk/test/SemaObjC/foreach.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/foreach.m?rev=300722&r1=300721&r2=300722&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/foreach.m (original)
+++ cfe/trunk/test/SemaObjC/foreach.m Wed Apr 19 12:54:08 2017
@@ -55,3 +55,27 @@ void test2(NSObject<NSFastEnumeration> *
   for (obj.prop in collection) { /* expected-error {{selector element is not a valid lvalue}} */
   }
 }
+
+int cond();
+
+void test3(NSObject<NSFastEnumeration> *a0, NSObject<NSFastEnumeration> *a1) {
+  for (id i in a0) { /* expected-note 2 {{jump enters Objective-C fast enumeration loop}} */
+    for (id j in a1) { /* expected-note 2 {{jump enters Objective-C fast enumeration loop}} */
+      (void)i, (void)j;
+label0:
+      if (cond())
+        goto label1;
+    }
+label1:
+    if (cond())
+      goto label0; /* expected-error {{cannot jump from this goto statement to its label}} */
+    if (cond())
+      goto label2;
+  }
+
+label2:
+  if (cond())
+    goto label0; /* expected-error {{cannot jump from this goto statement to its label}} */
+  if (cond())
+    goto label1; /* expected-error{{cannot jump from this goto statement to its label}} */
+}