Re: [PATCH] gold: add cast to gold_unreachable to workaround gcc giving invalid "no return statement" warnings

[Ian Lance Taylor <iant@google.com>]

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Mikolaj Zalewski <mikolajz@google.com> writes:

>   I couldn't compile gold today because of the "no return statement"
> warning when using gold_unreachable. At
> http://gcc.gnu.org/ml/gcc-bugs/2007-11/msg01605.html I've found a
> workaround that should work for gcc >= 3.4. Such a patch that affects
> only gold_unreachable is ok?
>
> 2009-08-13  Mikolaj Zalewski  <mikolajz@google.com>
>
> 	* gold.h (gold_unreachable): Add a cast.

I would prefer a patch like this one, which gives us a way to clean it
up a few years down the road.  Could you check whether this solves the
problem for you?  If it does, I'll commit it.  Thanks.

Ian


2009-08-14  Ian Lance Taylor  <iant@google.com>

	* gold.h (FUNCTION_NAME): Define.
	(gold_unreachable): Use FUNCTION_NAME.



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Index: gold.h
===================================================================
RCS file: /cvs/src/src/gold/gold.h,v
retrieving revision 1.39
diff -p -u -r1.39 gold.h
--- gold.h	5 Aug 2009 20:51:56 -0000	1.39
+++ gold.h	14 Aug 2009 08:30:51 -0000
@@ -253,11 +253,22 @@ gold_undefined_symbol_at_location(const 
 extern void
 gold_nomem() ATTRIBUTE_NORETURN;
 
+// In versions of gcc before 4.3, using __FUNCTION__ in a template
+// function can cause gcc to get confused about whether or not the
+// function can return.  See http://gcc.gnu.org/PR30988.  Use a macro
+// to avoid the problem.  This can be removed when we no longer need
+// to care about gcc versions before 4.3.
+#if defined(__GNUC__) && GCC_VERSION < 4003
+#define FUNCTION_NAME static_cast<const char*>(__FUNCTION__)
+#else 
+#define FUNCTION_NAME __FUNCTION__
+#endif
+
 // This macro and function are used in cases which can not arise if
 // the code is written correctly.
 
 #define gold_unreachable() \
-  (gold::do_gold_unreachable(__FILE__, __LINE__, __FUNCTION__))
+  (gold::do_gold_unreachable(__FILE__, __LINE__, FUNCTION_NAME))
 
 extern void do_gold_unreachable(const char*, int, const char*)
   ATTRIBUTE_NORETURN;