[llvm-commits] [PATCH] Add declaration of hash_value in APFloat / APInt (required for xlC on AIX)

[Kai]

Hi!

I am trying to compile LLVM with the IBM xlC compiler on AIX 7.1 The 
first issue I encounter is that the function hash_value() is declared as 
a friend of APFloat and APInt, but no matching declaration is provided. 
This results in the error message:

"../llvm-git/lib/Support/APFloat.cpp", line 2731.11: 1540-0432 (S) The 
qualified declarator "llvm::hash_value" must refer to an existing 
declaration.

The draft standard says in section 7.3.1.2 "Namespace member definitions":

"... If a friend declaration in a non-local class first declares a class 
or function95 the friend class or function is a member of the innermost 
enclosing namespace. The name of the friend is not found by unqualified 
lookup (3.4.1) or by qualified lookup (3.4.3) until a matching 
declaration is provided in that namespace scope (either before or after 
the class definition granting friendship). ..."

I conclude that the declaration is required for conformance with the C++ 
standard. The attached patch resolves the problem.

Please review and commit if it looks good.

Regards
Kai



-------------- next part --------------
diff --git a/include/llvm/ADT/APFloat.h b/include/llvm/ADT/APFloat.h
index 5a625a4..bcd1f6d 100644
--- a/include/llvm/ADT/APFloat.h
+++ b/include/llvm/ADT/APFloat.h
@@ -463,6 +463,9 @@ namespace llvm {
     exponent_t exponent2 : 11;
     unsigned int sign2: 1;
   };
+
+  // See friend declaration above.
+  hash_code hash_value(const APFloat &Arg);
 } /* namespace llvm */
 
 #endif /* LLVM_FLOAT_H */
diff --git a/include/llvm/ADT/APInt.h b/include/llvm/ADT/APInt.h
index 90114e2..ca6e1f6 100644
--- a/include/llvm/ADT/APInt.h
+++ b/include/llvm/ADT/APInt.h
@@ -1780,6 +1780,8 @@ inline APInt Not(const APInt& APIVal) {
 
 } // End of APIntOps namespace
 
+  // See friend declaration above.
+  hash_code hash_value(const APInt &Arg);
 } // End of llvm namespace
 
 #endif