From 053205cc4021026a5a1db05869d04bf7ad9ea1bd Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Mon, 16 Mar 2020 16:56:34 -0400 Subject: [PATCH] gdb: add Windows OS ABI GDB currently uses the "Cygwin" OS ABI (GDB_OSABI_CYGWIN) for everything related to Windows. If you build a GDB for a MinGW or Cygwin target, it will have "Cygwin" as the default OS ABI in both cases (see configure.tgt). If you load either a MinGW or Cygwin binary, the "Cygwin" OS ABI will be selected in both cases. This is misleading, because Cygwin binaries are a subset of the binaries running on Windows. When building something with MinGW, the resulting binary has nothing to do with Cygwin. Cygwin binaries are only special in that they are Windows binaries that link to the cygwin1.dll library (if my understanding is correct). Looking at i386-cygwin-tdep.c, we can see that GDB does nothing different when dealing with Cygwin binaries versus non-Cygwin Windows binaries. However, there is at least one known bug which would require us to make a distinction between the two OS ABIs, and that is the size of the built-in "long" type on x86-64. On native Windows, this is 4, whereas on Cygwin it's 8. So, this patch adds a new OS ABI, "Windows", and makes GDB use it for i386 and x86-64 PE executables, instead of the "Cygwin" OS ABI. A subsequent patch will improve the OS ABI detection so that GDB differentiates the non-Cygwin Windows binaries from the Cygwin Windows binaries, and applies the "Cygwin" OS ABI for the latter. The default OS ABI remains "Cygwin" for the GDBs built with a Cygwin target. I've decided to split the i386_cygwin_osabi_sniffer function in two, I think it's cleaner to have a separate sniffer for Windows binaries and Cygwin cores, each checking one specific thing. gdb/ChangeLog: * osabi.h (enum gdb_osabi): Add GDB_OSABI_WINDOWS. * osabi.c (gdb_osabi_names): Add "Windows". * i386-cygwin-tdep.c (i386_cygwin_osabi_sniffer): Return GDB_OSABI_WINDOWS when the binary's target is "pei-i386". (i386_cygwin_core_osabi_sniffer): New function, extracted from i386_cygwin_osabi_sniffer. (_initialize_i386_cygwin_tdep): Register OS ABI GDB_OSABI_WINDOWS for i386. * amd64-windows-tdep.c (amd64_windows_osabi_sniffer): Return GDB_OSABI_WINDOWS when the binary's target is "pei-x86-64". (_initialize_amd64_windows_tdep): Register OS ABI GDB_OSABI_WINDOWS for x86-64. * configure.tgt: Use GDB_OSABI_WINDOWS as the default OS ABI when the target matches '*-*-mingw*'. --- gdb/ChangeLog | 17 +++++++++++++++++ gdb/amd64-windows-tdep.c | 5 ++++- gdb/configure.tgt | 4 ++-- gdb/i386-cygwin-tdep.c | 17 ++++++++++++++--- gdb/osabi.c | 1 + gdb/osabi.h | 1 + 6 files changed, 39 insertions(+), 6 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 06c6343d39e..441029abf02 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,20 @@ +2020-03-16 Simon Marchi + + * osabi.h (enum gdb_osabi): Add GDB_OSABI_WINDOWS. + * osabi.c (gdb_osabi_names): Add "Windows". + * i386-cygwin-tdep.c (i386_cygwin_osabi_sniffer): Return + GDB_OSABI_WINDOWS when the binary's target is "pei-i386". + (i386_cygwin_core_osabi_sniffer): New function, extracted from + i386_cygwin_osabi_sniffer. + (_initialize_i386_cygwin_tdep): Register OS ABI + GDB_OSABI_WINDOWS for i386. + * amd64-windows-tdep.c (amd64_windows_osabi_sniffer): Return + GDB_OSABI_WINDOWS when the binary's target is "pei-x86-64". + (_initialize_amd64_windows_tdep): Register OS ABI GDB_OSABI_WINDOWS + for x86-64. + * configure.tgt: Use GDB_OSABI_WINDOWS as the default OS ABI + when the target matches '*-*-mingw*'. + 2020-03-16 Simon Marchi * defs.h (enum gdb_osabi): Move to... diff --git a/gdb/amd64-windows-tdep.c b/gdb/amd64-windows-tdep.c index 2ca979513cd..88ff794abcb 100644 --- a/gdb/amd64-windows-tdep.c +++ b/gdb/amd64-windows-tdep.c @@ -1250,7 +1250,7 @@ amd64_windows_osabi_sniffer (bfd *abfd) const char *target_name = bfd_get_target (abfd); if (strcmp (target_name, "pei-x86-64") == 0) - return GDB_OSABI_CYGWIN; + return GDB_OSABI_WINDOWS; return GDB_OSABI_UNKNOWN; } @@ -1259,6 +1259,9 @@ void _initialize_amd64_windows_tdep (); void _initialize_amd64_windows_tdep () { + /* The Cygwin and Windows OS ABIs are currently equivalent. */ + gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_WINDOWS, + amd64_windows_init_abi); gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_CYGWIN, amd64_windows_init_abi); diff --git a/gdb/configure.tgt b/gdb/configure.tgt index 755187dca65..6ebd32410e9 100644 --- a/gdb/configure.tgt +++ b/gdb/configure.tgt @@ -771,8 +771,8 @@ m68*-*-openbsd* | m88*-*-openbsd* | vax-*-openbsd*) ;; *-*-*-gnu*) ;; # prevent non-GNU kernels to match the Hurd rule below *-*-gnu*) gdb_osabi=GDB_OSABI_HURD ;; *-*-mingw32ce*) gdb_osabi=GDB_OSABI_WINCE ;; -*-*-mingw* | *-*-cygwin*) - gdb_osabi=GDB_OSABI_CYGWIN ;; +*-*-mingw*) gdb_osabi=GDB_OSABI_WINDOWS ;; +*-*-cygwin*) gdb_osabi=GDB_OSABI_CYGWIN ;; *-*-dicos*) gdb_osabi=GDB_OSABI_DICOS ;; *-*-symbianelf*) gdb_osabi=GDB_OSABI_SYMBIAN ;; diff --git a/gdb/i386-cygwin-tdep.c b/gdb/i386-cygwin-tdep.c index cb66632648f..b9a959d3c7d 100644 --- a/gdb/i386-cygwin-tdep.c +++ b/gdb/i386-cygwin-tdep.c @@ -232,14 +232,22 @@ i386_cygwin_osabi_sniffer (bfd *abfd) const char *target_name = bfd_get_target (abfd); if (strcmp (target_name, "pei-i386") == 0) - return GDB_OSABI_CYGWIN; + return GDB_OSABI_WINDOWS; + + return GDB_OSABI_UNKNOWN; +} + +static enum gdb_osabi +i386_cygwin_core_osabi_sniffer (bfd *abfd) +{ + const char *target_name = bfd_get_target (abfd); /* Cygwin uses elf core dumps. Do not claim all ELF executables, check whether there is a .reg section of proper size. */ if (strcmp (target_name, "elf32-i386") == 0) { asection *section = bfd_get_section_by_name (abfd, ".reg"); - if (section + if (section != nullptr && bfd_section_size (section) == I386_WINDOWS_SIZEOF_GREGSET) return GDB_OSABI_CYGWIN; } @@ -256,8 +264,11 @@ _initialize_i386_cygwin_tdep () /* Cygwin uses elf core dumps. */ gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour, - i386_cygwin_osabi_sniffer); + i386_cygwin_core_osabi_sniffer); + /* The Cygwin and Windows OS ABIs are currently equivalent. */ gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_CYGWIN, i386_cygwin_init_abi); + gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_WINDOWS, + i386_cygwin_init_abi); } diff --git a/gdb/osabi.c b/gdb/osabi.c index b9a8687a7cc..627b9d98151 100644 --- a/gdb/osabi.c +++ b/gdb/osabi.c @@ -72,6 +72,7 @@ static const struct osabi_names gdb_osabi_names[] = { "DJGPP", NULL }, { "QNX-Neutrino", NULL }, { "Cygwin", NULL }, + { "Windows", NULL }, { "AIX", NULL }, { "DICOS", NULL }, { "Darwin", NULL }, diff --git a/gdb/osabi.h b/gdb/osabi.h index ff63db49aff..a7e6a10d019 100644 --- a/gdb/osabi.h +++ b/gdb/osabi.h @@ -37,6 +37,7 @@ enum gdb_osabi GDB_OSABI_GO32, GDB_OSABI_QNXNTO, GDB_OSABI_CYGWIN, + GDB_OSABI_WINDOWS, GDB_OSABI_AIX, GDB_OSABI_DICOS, GDB_OSABI_DARWIN, -- 2.30.2