there i fixed it

Increase robustness of the delegating constructor cycle detection
mechanism. No more infinite loops on invalid or logic errors leading to
false results. Ensure that this is maintained correctly accross
serialization.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130887 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 74 insertions, 41 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 7b16d63a48..bb732e2c9f 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -7945,52 +7945,85 @@ void Sema::SetIvarInitializers(ObjCImplementationDecl *ObjCImplementation) {
   }
 }
 
-void Sema::CheckDelegatingCtorCycles() {
-  llvm::SmallSet<CXXConstructorDecl*, 4> Valid, Invalid, Current;
+static
+void DelegatingCycleHelper(CXXConstructorDecl* Ctor,
+                           llvm::SmallSet<CXXConstructorDecl*, 4> &Valid,
+                           llvm::SmallSet<CXXConstructorDecl*, 4> &Invalid,
+                           llvm::SmallSet<CXXConstructorDecl*, 4> &Current,
+                           Sema &S) {
+  llvm::SmallSet<CXXConstructorDecl*, 4>::iterator CI = Current.begin(),
+                                                   CE = Current.end();
+  if (Ctor->isInvalidDecl())
+    return;
 
-  llvm::SmallSet<CXXConstructorDecl*, 4>::iterator ci = Current.begin(),
-                                                   ce = Current.end();
+  const FunctionDecl *FNTarget = 0;
+  CXXConstructorDecl *Target;
+  
+  // We ignore the result here since if we don't have a body, Target will be
+  // null below.
+  (void)Ctor->getTargetConstructor()->hasBody(FNTarget);
+  Target
+= const_cast<CXXConstructorDecl*>(cast_or_null<CXXConstructorDecl>(FNTarget));
 
-  for (llvm::SmallVector<CXXConstructorDecl*, 4>::iterator
-         i = DelegatingCtorDecls.begin(),
-         e = DelegatingCtorDecls.end();
-       i != e; ++i) {
-    const FunctionDecl *FNTarget;
-    CXXConstructorDecl *Target;
-    (*i)->getTargetConstructor()->hasBody(FNTarget);
-    Target
-      = const_cast<CXXConstructorDecl*>(cast<CXXConstructorDecl>(FNTarget));
-
-    if (!Target || !Target->isDelegatingConstructor() || Valid.count(Target)) {
-      Valid.insert(*i);
-      for (ci = Current.begin(), ce = Current.end(); ci != ce; ++ci)
-        Valid.insert(*ci);
-      Current.clear();
-    } else if (Target == *i || Invalid.count(Target) || Current.count(Target)) {
-      if (!Invalid.count(Target)) {
-        Diag((*(*i)->init_begin())->getSourceLocation(),
+  CXXConstructorDecl *Canonical = Ctor->getCanonicalDecl(),
+                     // Avoid dereferencing a null pointer here.
+                     *TCanonical = Target ? Target->getCanonicalDecl() : 0;
+
+  if (!Current.insert(Canonical))
+    return;
+
+  // We know that beyond here, we aren't chaining into a cycle.
+  if (!Target || !Target->isDelegatingConstructor() ||
+      Target->isInvalidDecl() || Valid.count(TCanonical)) {
+    for (CI = Current.begin(), CE = Current.end(); CI != CE; ++CI)
+      Valid.insert(*CI);
+    Current.clear();
+  // We've hit a cycle.
+  } else if (TCanonical == Canonical || Invalid.count(TCanonical) ||
+             Current.count(TCanonical)) {
+    // If we haven't diagnosed this cycle yet, do so now.
+    if (!Invalid.count(TCanonical)) {
+      S.Diag((*Ctor->init_begin())->getSourceLocation(),
              diag::err_delegating_ctor_cycle)
-          << *i;
-        if (Target != *i)
-          Diag(Target->getLocation(), diag::note_it_delegates_to);
-        CXXConstructorDecl *Current = Target;
-        while (Current != *i) {
-          Current->getTargetConstructor()->hasBody(FNTarget);
-          Current
-         = const_cast<CXXConstructorDecl*>(cast<CXXConstructorDecl>(FNTarget));
-          Diag(Current->getLocation(), diag::note_which_delegates_to);
-        }
-      }
+        << Ctor;
+
+      // Don't add a note for a function delegating directo to itself.
+      if (TCanonical != Canonical)
+        S.Diag(Target->getLocation(), diag::note_it_delegates_to);
+
+      CXXConstructorDecl *C = Target;
+      while (C->getCanonicalDecl() != Canonical) {
+        (void)C->getTargetConstructor()->hasBody(FNTarget);
+        assert(FNTarget && "Ctor cycle through bodiless function");
 
-      (*i)->setInvalidDecl();
-      Invalid.insert(*i);
-      for (ci = Current.begin(), ce = Current.end(); ci != ce; ++ci) {
-        (*ci)->setInvalidDecl();
-        Invalid.insert(*i);
+        C
+       = const_cast<CXXConstructorDecl*>(cast<CXXConstructorDecl>(FNTarget));
+        S.Diag(C->getLocation(), diag::note_which_delegates_to);
       }
-      Current.clear();
-    } else {
-      Current.insert(*i);
     }
+
+    for (CI = Current.begin(), CE = Current.end(); CI != CE; ++CI)
+      Invalid.insert(*CI);
+    Current.clear();
+  } else {
+    DelegatingCycleHelper(Target, Valid, Invalid, Current, S);
+  }
+}
+   
+
+void Sema::CheckDelegatingCtorCycles() {
+  llvm::SmallSet<CXXConstructorDecl*, 4> Valid, Invalid, Current;
+
+  llvm::SmallSet<CXXConstructorDecl*, 4>::iterator CI = Current.begin(),
+                                                   CE = Current.end();
+
+  for (llvm::SmallVector<CXXConstructorDecl*, 4>::iterator
+         I = DelegatingCtorDecls.begin(),
+         E = DelegatingCtorDecls.end();
+       I != E; ++I) {
+   DelegatingCycleHelper(*I, Valid, Invalid, Current, *this);
   }
+
+  for (CI = Invalid.begin(), CE = Invalid.end(); CI != CE; ++CI)
+    (*CI)->setInvalidDecl();
 }