Misc fixes for -Wreorder:

1. Make it work correctly with anonymous unions.
2. Don't compute it if the warning isn't enabled.
3. Optimize the algorithm slightly to make it linear time in the 
case where we don't produce any warnings.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76630 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaDeclCXX.cpp

@@ -774,6 +774,29 @@ Sema::ActOnMemInitializer(DeclPtrTy ConstructorD,
                                         IdLoc);
 }
 
+static void *GetKeyForTopLevelField(FieldDecl *Field) {
+  // For anonymous unions, use the class declaration as the key.
+  if (const RecordType *RT = Field->getType()->getAsRecordType()) {
+    if (RT->getDecl()->isAnonymousStructOrUnion())
+      return static_cast<void *>(RT->getDecl());
+  }
+  return static_cast<void *>(Field);
+}
+
+static void *GetKeyForMember(CXXBaseOrMemberInitializer *Member) {
+  // For fields injected into the class via declaration of an anonymous union,
+  // use its anonymous union class declaration as the unique key.
+  if (FieldDecl *Field = Member->getMember()) {
+    if (Field->getDeclContext()->isRecord()) {
+      RecordDecl *RD = cast<RecordDecl>(Field->getDeclContext());
+      if (RD->isAnonymousStructOrUnion())
+        return static_cast<void *>(RD);
+    }
+    return static_cast<void *>(Field);
+  }
+  return static_cast<RecordType *>(Member->getBaseClass());
+}
+
 void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl, 
                                 SourceLocation ColonLoc,
                                 MemInitTy **MemInits, unsigned NumMemInits) {
@@ -792,13 +815,7 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
   for (unsigned i = 0; i < NumMemInits; i++) {
     CXXBaseOrMemberInitializer *Member = 
       static_cast<CXXBaseOrMemberInitializer*>(MemInits[i]);
-    void *KeyToMember = Member->getBaseOrMember();
-    // For fields injected into the class via declaration of an anonymous union,
-    // use its anonymous union class declaration as the unique key.
-    if (FieldDecl *Field = Member->getMember())
-      if (Field->getDeclContext()->isRecord() &&
-          cast<RecordDecl>(Field->getDeclContext())->isAnonymousStructOrUnion())
-        KeyToMember = static_cast<void *>(Field->getDeclContext());
+    void *KeyToMember = GetKeyForMember(Member);
     CXXBaseOrMemberInitializer *&PrevMember = Members[KeyToMember];
     if (!PrevMember) {
       PrevMember = Member;
@@ -823,6 +840,11 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
     Constructor->setBaseOrMemberInitializers(Context, 
                     reinterpret_cast<CXXBaseOrMemberInitializer **>(MemInits), 
                     NumMemInits);
+  }
+  if (!err && (Diags.getDiagnosticLevel(diag::warn_base_initialized)
+               != Diagnostic::Ignored ||
+               Diags.getDiagnosticLevel(diag::warn_field_initialized)
+               != Diagnostic::Ignored)) {
     // Also issue warning if order of ctor-initializer list does not match order
     // of 1) base class declarations and 2) order of non-static data members.
     llvm::SmallVector<const void*, 32> AllBaseOrMembers;
@@ -846,7 +868,7 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
     
     for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(),
          E = ClassDecl->field_end(); Field != E; ++Field)
-      AllBaseOrMembers.push_back(*Field);
+      AllBaseOrMembers.push_back(GetKeyForTopLevelField(*Field));
     
     int Last = AllBaseOrMembers.size();
     int curIndex = 0;
@@ -854,19 +876,13 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
     for (unsigned i = 0; i < NumMemInits; i++) {
       CXXBaseOrMemberInitializer *Member = 
         static_cast<CXXBaseOrMemberInitializer*>(MemInits[i]);
-      void *MemberInCtorList;
-      if (Member->isBaseInitializer())
-        MemberInCtorList = Member->getBaseClass();
-      else
-        MemberInCtorList = Member->getMember();
+      void *MemberInCtorList = GetKeyForMember(Member);
 
-      int j;
-      for (j = curIndex; j < Last; j++)
-        if (MemberInCtorList == AllBaseOrMembers[j])
+      for (; curIndex < Last; curIndex++)
+        if (MemberInCtorList == AllBaseOrMembers[curIndex])
           break;
-      if (j == Last) {
-        if (!PrevMember)
-          continue;
+      if (curIndex == Last) {
+        assert(PrevMember && "Member not in member list?!");
         // Initializer as specified in ctor-initializer list is out of order.
         // Issue a warning diagnostic.
         if (PrevMember->isBaseInitializer()) {
@@ -893,11 +909,11 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
                diag::note_fieldorbase_initialized_here) << 1
             << BaseClass->getDesugaredType(true);
         }
+        for (curIndex = 0; curIndex < Last; curIndex++)
+          if (MemberInCtorList == AllBaseOrMembers[curIndex]) 
+            break;
       }
       PrevMember = Member;
-      for (curIndex=0; curIndex < Last; curIndex++)
-        if (MemberInCtorList == AllBaseOrMembers[curIndex]) 
-          break;
     }
   }
 }

test/SemaCXX/warn-reorder-ctor-initialization.cpp

@@ -73,4 +73,17 @@ struct X : public virtual A, virtual V, public virtual B {
 			// expected-note {{base 'struct V'}}
 };
 
-
+class Anon {
+  int c; union {int a,b;}; int d;
+  Anon() : c(10), b(1), d(2) {}
+};
+class Anon2 {
+  int c; union {int a,b;}; int d;
+  Anon2() : c(2),
+            d(10), // expected-warning {{member 'd' will be initialized after}}
+            b(1) {} // expected-note {{field b}}
+};
+class Anon3 {
+  union {int a,b;};
+  Anon3() : b(1) {}
+};