[PATCH] D32187: [CodeGen][ObjC]

[Akira Hatanaka via Phabricator via cfe-commits]

ahatanak updated this revision to Diff 95667.
ahatanak added a comment.

Unconditionally ban jumping into body of ObjC fast enumeration loop.


https://reviews.llvm.org/D32187

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


Index: test/SemaObjC/foreach.m
===================================================================
--- test/SemaObjC/foreach.m
+++ test/SemaObjC/foreach.m
@@ -55,3 +55,27 @@
   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 body}} */
+    for (id j in a1) { /* expected-note 2 {{jump enters Objective-c fast enumeration loop body}} */
+      (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}} */
+}
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -1783,6 +1783,7 @@
 Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
                                  Stmt *First, Expr *collection,
                                  SourceLocation RParenLoc) {
+  getCurFunction()->setHasBranchProtectedScope();
 
   ExprResult CollectionExprResult =
     CheckObjCForCollectionOperand(ForLoc, collection);
Index: lib/Sema/JumpDiagnostics.cpp
===================================================================
--- lib/Sema/JumpDiagnostics.cpp
+++ lib/Sema/JumpDiagnostics.cpp
@@ -287,6 +287,15 @@
     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
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -4981,6 +4981,8 @@
   "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 body">;
 def note_protected_by_objc_try : Note<
   "jump bypasses initialization of @try block">;
 def note_protected_by_objc_catch : Note<


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