Fix missing recovery from faults in GC_mark_some on Win64 if MinGW

Issue #454 (bdwgc).

This fixes rare SIGSEGV events in GC_mark_some on Windows (and Wine)
when Windows asynchronously removes some temporary data roots if the
collector is built e.g. with a MinGW-w64 compiler.

Now, on Windows, the faults are caught by setjmp/longjmp if SEH is not
supported by the compiler.

Also, the asm-based implementation of SEH faults handling for x86 is
deleted (thus, no specific handling of x86 any more) because it relied
on a certain compilation mode (that the standard function prologue is
generated and frame pointer is not omitted).

* include/private/gc_priv.h [WRAP_MARK_SOME && __GNUC__] (GC_jmp_buf,
GC_setup_temporary_fault_handler, GC_reset_fault_handler): Declare.
* include/private/gcconfig.h [(MSWIN32 || MSWINCE) && !NO_CRT
&& !NO_WRAP_MARK_SOME] (WRAP_MARK_SOME): Define regardless of __GNUC__
and I386; remove FIXME item; update TODO item.
* mark.c [__MINGW32__ && !__MINGW_EXCPT_DEFINE_PSDK && __i386__]
(__MINGW_EXCPT_DEFINE_PSDK): Do not define; remove comment.
* mark.c [MSWIN32 && __GNUC__]: Do not include excpt.h.
* mark.c [WRAP_MARK_SOME] (GC_mark_some_inner): Update comment.
* mark.c [WRAP_MARK_SOME && (MSWIN32 || MSWINCE) && __GNUC__]
(ext_ex_regn): Remove type declaration.
* mark.c [WRAP_MARK_SOME && (MSWIN32 || MSWINCE) && __GNUC__]
(mark_ex_handler): Remove static function.
* mark.c [WRAP_MARK_SOME] (GC_mark_some): Update comment (remove exact
versions of Windows).
* mark.c [WRAP_MARK_SOME && (MSWIN32 || MSWINCE) && __GNUC__]
(GC_mark_some): Use GC_setup_temporary_fault_handler, SETJMP() and
GC_reset_fault_handler instead of asm-based emulation of __try/except.
* mark.c [WRAP_MARK_SOME && (!MSWIN32 && !MSWINCE || __GNUC__)
&& !DEFAULT_VDB] (GC_mark_some): WARN() only if USE_PROC_FOR_LIBRARIES.
* mark.c [WRAP_MARK_SOME && !MSWIN32 && !MSWINCE] (GC_mark_some):
Remove rm_handler label (call GC_reset_fault_handler on handle_ex
instead).
* mark.c [WRAP_MARK_SOME && !MSWIN32 && !MSWINCE && __GNUC__
&& GC_WIN32_THREADS && !GC_PTHREADS] (GC_mark_some): Call
GC_started_thread_while_stopped() (after GC_reset_fault_handler).
* mark.c [WRAP_MARK_SOME && GC_WIN32_THREADS && !GC_PTHREADS]
(GC_mark_some): Define handle_thr_start label regardless of MSWIN32
and MSWINCE.
* mark.c [WRAP_MARK_SOME] (GC_mark_some): Return FALSE instead of
setting ret_val to FALSE and going to rm_handler (because
GC_reset_fault_handler is already called).
* os_dep.c [WRAP_MARK_SOME && __GNUC__] (GC_fault_handler_t): Define
type.
* os_dep.c [WRAP_MARK_SOME && __GNUC__] (GC_set_and_save_fault_handler,
GC_jmp_buf, GC_fault_handler, GC_setup_temporary_fault_handler,
GC_reset_fault_handler): Define.

1 files changed, 4 insertions, 2 deletions

diff --git a/os_dep.c b/os_dep.c
index 8e2d98eb..d4ba3336 100644
--- a/os_dep.c
+++ b/os_dep.c
@@ -871,7 +871,8 @@ GC_INNER size_t GC_page_size = 0;
 # endif /* AMIGA */
 
 # if defined(NEED_FIND_LIMIT) || defined(UNIX_LIKE) \
-     || (defined(WRAP_MARK_SOME) && !defined(MSWIN32) && !defined(MSWINCE))
+     || (defined(WRAP_MARK_SOME) && (!defined(MSWIN32) && !defined(MSWINCE) \
+                                     || defined(__GNUC__)))
 
     typedef void (*GC_fault_handler_t)(int);
 
@@ -931,7 +932,8 @@ GC_INNER size_t GC_page_size = 0;
 # endif /* NEED_FIND_LIMIT || UNIX_LIKE */
 
 # if defined(NEED_FIND_LIMIT) \
-     || (defined(WRAP_MARK_SOME) && !defined(MSWIN32) && !defined(MSWINCE)) \
+     || (defined(WRAP_MARK_SOME) && (!defined(MSWIN32) && !defined(MSWINCE) \
+                                     || defined(__GNUC__))) \
      || (defined(USE_PROC_FOR_LIBRARIES) && defined(THREADS))
   /* Some tools to implement HEURISTIC2 */
 #   define MIN_PAGE_SIZE 256    /* Smallest conceivable page size, bytes */