binutils-gdb/gdb/windows-tdep.h
Simon Marchi 0f2265e246 gdb: stop using host-dependent signal numbers in windows-tdep.c
The signal enumeration in windows-tdep.c is defined differently whether
it is compiled on Cygwin or not.  This is problematic, since the code in
tdep files is not supposed to be influenced by the host platform (the
platform GDB itself runs on).

This makes a difference in windows_gdb_signal_to_target.  An obvious
example of clash is SIGABRT.  Let's pretend we are cross-debugging a
Cygwin process from a MinGW (non-Cygwin Windows) GDB.  If GDB needs to
translate the gdb signal number GDB_SIGNAL_ABRT into a target
equivalent, it would obtain the MinGW number (22), despite the target
being a Cygwin process.  Conversely, if debugging a MinGW process from a
Cygwin-hosted GDB, GDB_SIGNAL_ABRT would be converted to a Cygwin signal
number (6) despite the target being a MinGW process.  This is wrong,
since we want the result to depend on the target's platform, not GDB's
platform.

This known flaw was accepted because at the time we had a single OS ABI
(called Cygwin) for all Windows binaries (Cygwin ones and non-Cygwin
ones).  This limitation is now lifted, as we now have separate Windows
and Cygwin OS ABIs.  This means we are able to detect at runtime whether
the binary we are debugging is a Cygwin one or non-Cygwin one.

This patch splits the signal enum in two, one for the MinGW flavors and
one for Cygwin, removing all the ifdefs that made it depend on the host
platform.  It then makes two separate gdb_signal_to_target gdbarch
methods, that are used according to the OS ABI selected at runtime.

There is a bit of re-shuffling needed in how the gdbarch'es are
initialized, but nothing major.

gdb/ChangeLog:

	* windows-tdep.h (windows_init_abi): Add comment.
	(cygwin_init_abi): New declaration.
	* windows-tdep.c: Split signal enumeration in two, one for
	Windows and one for Cygwin.
	(windows_gdb_signal_to_target): Only deal with signal of the
	Windows OS ABI.
	(cygwin_gdb_signal_to_target): New function.
	(windows_init_abi): Rename to windows_init_abi_common, don't set
	gdb_signal_to_target gdbarch method.  Add new new function with
	this name.
	(cygwin_init_abi): New function.
	* amd64-windows-tdep.c (amd64_windows_init_abi_common): Add
	comment.  Don't call windows_init_abi.
	(amd64_windows_init_abi): Add comment, call windows_init_abi.
	(amd64_cygwin_init_abi): Add comment, call cygwin_init_abi.
	* i386-windows-tdep.c (i386_windows_init_abi): Rename to
	i386_windows_init_abi_common, don't call windows_init_abi.  Add
	a new function of this name.
	(i386_cygwin_init_abi): New function.
	(_initialize_i386_windows_tdep): Bind i386_cygwin_init_abi to
	OS ABI Cygwin.
2020-04-08 14:05:54 -04:00

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C

/* Copyright (C) 2008-2020 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef WINDOWS_TDEP_H
#define WINDOWS_TDEP_H
struct obstack;
struct gdbarch;
extern struct cmd_list_element *info_w32_cmdlist;
extern void init_w32_command_list (void);
extern void windows_xfer_shared_library (const char* so_name,
CORE_ADDR load_addr,
CORE_ADDR *text_offset_cached,
struct gdbarch *gdbarch,
struct obstack *obstack);
/* To be called from the various GDB_OSABI_WINDOWS handlers for the
various Windows architectures and machine types. */
extern void windows_init_abi (struct gdbarch_info info,
struct gdbarch *gdbarch);
/* To be called from the various GDB_OSABI_CYGWIN handlers for the
various Windows architectures and machine types. */
extern void cygwin_init_abi (struct gdbarch_info info,
struct gdbarch *gdbarch);
/* Return true if the Portable Executable behind ABFD uses the Cygwin dll
(cygwin1.dll). */
extern bool is_linked_with_cygwin_dll (bfd *abfd);
#endif