From patchwork Mon Oct 15 20:51:05 2012
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Subject: Install error handler for out-of-memory when using STL containers Re:
 PR fortran/51727: make module files reproducible, question on C++ in gcc
Date: Mon, 15 Oct 2012 10:51:05 -0000
From: =?utf-8?q?Tobias_Schl=C3=BCter_=3Ctobias=2Eschlueter=40physik=2Euni-m?=
 =?utf-8?q?uenchen=2Ede=3E?=
X-Patchwork-Id: 191664
Message-Id: <507C7739.3070003@physik.uni-muenchen.de>
To: Jakub Jelinek <jakub@redhat.com>
Cc: gcc-patches <gcc-patches@gcc.gnu.org>

Hi,

On 2012-10-14 23:44, Jakub Jelinek wrote:
> On Mon, Oct 15, 2012 at 12:35:27AM +0300, Janne Blomqvist wrote:
>> On Sat, Oct 13, 2012 at 4:26 PM, Tobias Schlüter
>>> I'm putting forward two patches.  One uses a C++ map to very concisely build
>>> up and handle the ordered list of symbols.  This has three problems:
>>> 1) gfortran maintainers may not want C++isms (even though in this case
>>>     it's very localized, and in my opinion very transparent), and
>
> Even if you prefer a C++isms, why don't you go for "hash-table.h"?
> std::map at least with the default allocator will just crash the compiler
> if malloc returns NULL (remember that we build with -fno-exceptions),
> while when you use hash-table.h (or hashtab.h) you get proper OOM diagnostics.

The attached patch adds out-of-memory diagnostics for code using STL 
containers by using set_new_handler.  Since the intended allocation size 
is not available to a new_handler, I had to forego a more detailed error 
message such as the one from xmalloc_failed().  fatal_error() and 
abort() don't give a meaningful location when the new_handler is called, 
so I chose to put together the error message manually as is done in 
xmalloc_failed().  I would have found it more appealing to have operator 
new call xmalloc() unless a custom allocator is given, but I don't think 
there's a standard way of doing this.

Built and tested on the C and Fortran testsuites.  Ok for trunk?

Cheers,
- Tobi
2012-10-15  Tobias Schlüter  <tobi@gcc.gnu.org>

	* toplev.c: Add '#include <new>'.
	(cxx_out_of_memory): New function.
	(general_init): Install cxx_out_of_memory as handler for
	out-of-memory condition.


diff --git a/gcc/toplev.c b/gcc/toplev.c
index 2c9329f..2e6248a 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -89,6 +89,8 @@ along with GCC; see the file COPYING3.  If not see
 				   declarations for e.g. AIX 4.x.  */
 #endif
 
+#include <new>
+
 static void general_init (const char *);
 static void do_compile (void);
 static void process_options (void);
@@ -1061,6 +1063,21 @@ open_auxiliary_file (const char *ext)
   return file;
 }
 
+
+/* Error handler for use with C++ memory allocation.  Will be
+   installed via std::set_new_handler().  */
+
+static void
+cxx_out_of_memory()
+{
+  fprintf (stderr,
+	   "\n%s%sout of memory\n",
+	   progname, *progname ? ": " : "");
+
+  xexit (1);
+}
+
+
 /* Initialization of the front end environment, before command line
    options are parsed.  Signal handlers, internationalization etc.
    ARGV0 is main's argv[0].  */
@@ -1074,6 +1091,8 @@ general_init (const char *argv0)
     --p;
   progname = p;
 
+  std::set_new_handler (cxx_out_of_memory);
+
   xmalloc_set_program_name (progname);
 
   hex_init ();