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If xmalloc fails allocating memory, usually because something tried a huge allocation, like xmalloc(-1) or some such, GDB asks the user what to do: .../src/gdb/utils.c:1079: internal-error: virtual memory exhausted. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) If the user says "n", that throws a QUIT exception, which is caught by one of the multiple CATCH(RETURN_MASK_ALL) blocks somewhere up the stack. The default implementations of operator new / operator new[] call malloc directly, and on memory allocation failure throw std::bad_alloc. Currently, if that happens, since nothing catches it, the exception escapes out of main, and GDB aborts from unhandled exception. This patch replaces the default operator new variants with versions that, just like xmalloc: #1 - Raise an internal-error on memory allocation failure. #2 - Throw a QUIT gdb_exception, so that the exact same CATCH blocks continue handling memory allocation problems. A minor complication of #2 is that operator new can _only_ throw std::bad_alloc, or something that extends it: void* operator new (std::size_t size) throw (std::bad_alloc); That means that if we let a gdb QUIT exception escape from within operator new, the C++ runtime aborts due to unexpected exception thrown. So to bridge the gap, this patch adds a new gdb_quit_bad_alloc exception type that inherits both std::bad_alloc and gdb_exception, and throws _that_. If we decide that we should be catching memory allocation errors in fewer places than all the places we currently catch them (everywhere we use RETURN_MASK_ALL currently), then we could change operator new to throw plain std::bad_alloc then. But I'm considering such a change as separate matter from this one -- it'd make sense to do the same to xmalloc at the same time, for instance. Meanwhile, this allows using new/new[] instead of xmalloc/XNEW/etc. without losing the "virtual memory exhausted" internal-error safeguard. Tested on x86_64 Fedora 23. gdb/ChangeLog: 2016-09-23 Pedro Alves <palves@redhat.com> * Makefile.in (SFILES): Add common/new-op.c. (COMMON_OBS): Add common/new-op.o. (new-op.o): New rule. * common/common-exceptions.h: Include <new>. (struct gdb_quit_bad_alloc): New type. * common/new-op.c: New file. gdb/gdbserver/ChangeLog: 2016-09-23 Pedro Alves <palves@redhat.com> * Makefile.in (SFILES): Add common/new-op.c. (OBS): Add common/new-op.o. (new-op.o): New rule.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.