Merge function types in C.

Among other differences, GCC accepts

  typedef int IA[];
  typedef int A10[10];
  static A10 *f(void);
  static IA  *f(void);
  void g(void) {
    (void)sizeof(*f());
  }

but clang used to reject it with:

  invalid application of 'sizeof' to an incomplete type 'IA' (aka 'int []')

The intention of c99's 6.2.7 seems to be that we should use the composite type
and accept as gcc does.

Doing the type merging required some extra fixes:
  * Use the type from the function type in initializations, even if an parameter
    is available.
  * Fix the merging of the noreturn attribute in function types.
  * Make CodeGen  handle the fact that an parameter type can be different from
    the corresponding type in the function type.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@168895 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 5 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 7fee560534..26c2941804 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -6486,14 +6486,14 @@ QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs,
   if (lbaseInfo.getProducesResult() != rbaseInfo.getProducesResult())
     return QualType();
 
-  // functypes which return are preferred over those that do not.
-  if (lbaseInfo.getNoReturn() && !rbaseInfo.getNoReturn())
-    allLTypes = false;
-  else if (!lbaseInfo.getNoReturn() && rbaseInfo.getNoReturn())
-    allRTypes = false;
   // FIXME: some uses, e.g. conditional exprs, really want this to be 'both'.
   bool NoReturn = lbaseInfo.getNoReturn() || rbaseInfo.getNoReturn();
 
+  if (lbaseInfo.getNoReturn() != NoReturn)
+    allLTypes = false;
+  if (rbaseInfo.getNoReturn() != NoReturn)
+    allRTypes = false;
+
   FunctionType::ExtInfo einfo = lbaseInfo.withNoReturn(NoReturn);
 
   if (lproto && rproto) { // two C99 style function prototypes