Re: C++: missing result_decl loc of (member) functions

[Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>]

On Wed, 20 Apr 2022 19:20:24 +0200
Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> wrote:

> Hi!
> 
> I'm having a hard time to set the correct location of the result decl of
> member functions in C++. Any hint on where to best fix the missing
> locus?
> TIA for any hint (or a fix :).
> 
> Long version:

> ¹) C functions work out fine once fixed to have the correct loc.
>    C++ functions worked fine once, but i now see that apparently
>    "int my_main" on line 42 regressed again in the meantime:

This is due to decl1 having been ggc_freed here:

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index c136dbbba1a..38874bf1558 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -17373,7 +17375,18 @@ start_function (cp_decl_specifier_seq *declspecs,
     gcc_assert (same_type_p (TREE_TYPE (TREE_TYPE (decl1)),
 			     integer_type_node));
 
-  return start_preparsed_function (decl1, attrs, /*flags=*/SF_DEFAULT);
+  ret = start_preparsed_function (decl1, attrs, /*flags=*/SF_DEFAULT);
+
+  /* decl1 might be ggc_freed here.  */
+  //decl1 = current_function_decl;
+

which is why i previously had to use current_function_decl here.
> 
> 
> $ XXX=1 ../gcc/xg++ -B../gcc -c -o return-narrow.o return-narrow.cc -fdiagnostics-color=always 

> return-narrow.cc: In function ‘int my_main(int, char**)’:
> return-narrow.cc:42:25: warning: result decl locus sample
>    42 | int my_main (int, char**) { return 0; }
>       |                         ^
>       |                         the return type