[C++ PATCH] Fix ICE in ~macro_use_before_def (PR preprocessor/83602)

[C++ PATCH] Fix ICE in ~macro_use_before_def (PR preprocessor/83602)

[Jakub Jelinek]

Hi!

If lookup_name_fuzzy finds an exact match with a macro, it later in the dtor
uses node->value.macro->line in libcpp.  The problem is that for builtin
macros node->value.macro contains garbage, we use node->value.builtin union
member in those cases instead.  It doesn't make any sense to look up
location of a builtin macro definition anyway, those are very special
entities.  So, this patch just ignores those, because we can't do anything
useful with them.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2018-01-02  Jakub Jelinek  <jakub@redhat.com>

	PR preprocessor/83602
	* name-lookup.c (lookup_name_fuzzy): Don't use macro_use_before_def
	for builtin macros.

	* g++.dg/cpp/pr83602.C: New test.

--- gcc/cp/name-lookup.c.jj	2017-12-19 18:09:05.828304241 +0100
+++ gcc/cp/name-lookup.c	2018-01-02 14:00:36.616761370 +0100
@@ -5757,7 +5757,7 @@ lookup_name_fuzzy (tree name, enum looku
       /* If we have an exact match for a macro name, then the
 	 macro has been used before it was defined.  */
       cpp_hashnode *macro = bmm.blithely_get_best_candidate ();
-      if (macro)
+      if (macro && (macro->flags & NODE_BUILTIN) == 0)
 	return name_hint (NULL,
 			  new macro_use_before_def (loc, macro));
     }
--- gcc/testsuite/g++.dg/cpp/pr83602.C.jj	2018-01-02 14:04:48.062827484 +0100
+++ gcc/testsuite/g++.dg/cpp/pr83602.C	2018-01-02 14:03:56.517813869 +0100
@@ -0,0 +1,4 @@
+// PR preprocessor/83602
+// { dg-do compile }
+
+_Pragma	// { dg-error "_Pragma" }

	Jakub

Re: [C++ PATCH] Fix ICE in ~macro_use_before_def (PR preprocessor/83602)

[Nathan Sidwell]

On 01/02/2018 04:07 PM, Jakub Jelinek wrote:
> Hi!
> 
> If lookup_name_fuzzy finds an exact match with a macro, it later in the dtor
> uses node->value.macro->line in libcpp.  The problem is that for builtin
> macros node->value.macro contains garbage, we use node->value.builtin union
> member in those cases instead.  It doesn't make any sense to look up
> location of a builtin macro definition anyway, those are very special
> entities.  So, this patch just ignores those, because we can't do anything
> useful with them.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
> 
> 2018-01-02  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR preprocessor/83602
> 	* name-lookup.c (lookup_name_fuzzy): Don't use macro_use_before_def
> 	for builtin macros.
> 
> 	* g++.dg/cpp/pr83602.C: New test.

ok


-- 
Nathan Sidwell