Further weaken block conversion rules to permit blocks with

enum return type to be converted to blocks with any integer type
of the same size.

rdar://13463504

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177613 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 25 insertions, 10 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index b55a926e32..eee7ed2fb8 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -6844,6 +6844,27 @@ QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs,
   return getFunctionNoProtoType(retType, einfo);
 }
 
+/// Given that we have an enum type and a non-enum type, try to merge them.
+static QualType mergeEnumWithInteger(ASTContext &Context, const EnumType *ET,
+                                     QualType other, bool isBlockReturnType) {
+  // C99 6.7.2.2p4: Each enumerated type shall be compatible with char,
+  // a signed integer type, or an unsigned integer type.
+  // Compatibility is based on the underlying type, not the promotion
+  // type.
+  QualType underlyingType = ET->getDecl()->getIntegerType();
+  if (underlyingType.isNull()) return QualType();
+  if (Context.hasSameType(underlyingType, other))
+    return other;
+
+  // In block return types, we're more permissive and accept any
+  // integral type of the same size.
+  if (isBlockReturnType && other->isIntegerType() &&
+      Context.getTypeSize(underlyingType) == Context.getTypeSize(other))
+    return other;
+
+  return QualType();
+}
+
 QualType ASTContext::mergeTypes(QualType LHS, QualType RHS, 
                                 bool OfBlockPointer,
                                 bool Unqualified, bool BlockReturnType) {
@@ -6925,19 +6946,13 @@ QualType ASTContext::mergeTypes(QualType LHS, QualType RHS,
 
   // If the canonical type classes don't match.
   if (LHSClass != RHSClass) {
-    // C99 6.7.2.2p4: Each enumerated type shall be compatible with char,
-    // a signed integer type, or an unsigned integer type.
-    // Compatibility is based on the underlying type, not the promotion
-    // type.
+    // Note that we only have special rules for turning block enum
+    // returns into block int returns, not vice-versa.
     if (const EnumType* ETy = LHS->getAs<EnumType>()) {
-      QualType TINT = ETy->getDecl()->getIntegerType();
-      if (!TINT.isNull() && hasSameType(TINT, RHSCan.getUnqualifiedType()))
-        return RHS;
+      return mergeEnumWithInteger(*this, ETy, RHS, false);
     }
     if (const EnumType* ETy = RHS->getAs<EnumType>()) {
-      QualType TINT = ETy->getDecl()->getIntegerType();
-      if (!TINT.isNull() && hasSameType(TINT, LHSCan.getUnqualifiedType()))
-        return LHS;
+      return mergeEnumWithInteger(*this, ETy, LHS, BlockReturnType);
     }
     // allow block pointer type to match an 'id' type.
     if (OfBlockPointer && !BlockReturnType) {