Re: [Mingw-w64-public] [PATCHv3] crt: Avoid optimizing fprintf calls into fwrite in crt startup code

[Martin Storsjö]

On Fri, 29 Sep 2017, Martin Storsjö wrote:


By avoiding turning fprintf(stderr,) into fwrite(stderr,) we can localize
the compat wrapping for that to fprintf. Then we shouldn't ever need to
worry about functions needing init_compat to be called before they're
invoked by the constructor.

This allows simplifying the ucrtbase_compat.c code quite significantly.

Signed-off-by: Martin Storsjö 
---
Moved the -fno-builtin-fprintf to lib*_libmingw32_a_CFLAGS.
---
mingw-w64-crt/Makefile.am   |  4 
mingw-w64-crt/crt/ucrtbase_compat.c | 42 +
2 files changed, 5 insertions(+), 41 deletions(-)


This was ok'd by Jacek on irc, so pushing.

// Martin
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[Mingw-w64-public] [PATCHv3] crt: Avoid optimizing fprintf calls into fwrite in crt startup code

[Martin Storsjö]

By avoiding turning fprintf(stderr,) into fwrite(stderr,) we can localize
the compat wrapping for that to fprintf. Then we shouldn't ever need to
worry about functions needing init_compat to be called before they're
invoked by the constructor.

This allows simplifying the ucrtbase_compat.c code quite significantly.

Signed-off-by: Martin Storsjö 
---
Moved the -fno-builtin-fprintf to lib*_libmingw32_a_CFLAGS.
---
 mingw-w64-crt/Makefile.am   |  4 
 mingw-w64-crt/crt/ucrtbase_compat.c | 42 +
 2 files changed, 5 insertions(+), 41 deletions(-)

diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index 8e8494e..eaa0080 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -596,6 +596,7 @@ lib32_liblargeint_a_CPPFLAGS=$(CPPFLAGS32) $(sysincludes)
 
 lib32_LIBRARIES += lib32/libmingw32.a
 lib32_libmingw32_a_CPPFLAGS=$(CPPFLAGS32) -D_SYSCRT=1 -DCRTDLL=1 
$(extra_include) $(AM_CPPFLAGS)
+lib32_libmingw32_a_CFLAGS=-fno-builtin-fprintf $(AM_CFLAGS)
 lib32_libmingw32_a_SOURCES = $(src_libmingw32)
 
 lib32_LIBRARIES += lib32/libmingwex.a
@@ -903,6 +904,7 @@ lib64_liblargeint_a_CPPFLAGS=$(CPPFLAGS64) $(sysincludes)
 
 lib64_LIBRARIES += lib64/libmingw32.a
 lib64_libmingw32_a_CPPFLAGS=$(CPPFLAGS64) -D_SYSCRT=1 -DCRTDLL=1 
$(extra_include) $(AM_CPPFLAGS)
+lib64_libmingw32_a_CFLAGS=-fno-builtin-fprintf $(AM_CFLAGS)
 lib64_libmingw32_a_SOURCES = $(src_libmingw32)
 
 lib64_LIBRARIES += lib64/libmingwex.a
@@ -1208,6 +1210,7 @@ libarm32_liblargeint_a_CPPFLAGS=$(CPPFLAGSARM32) 
$(sysincludes)
 
 libarm32_LIBRARIES += libarm32/libmingw32.a
 libarm32_libmingw32_a_CPPFLAGS=$(CPPFLAGSARM32) -D_SYSCRT=1 -DCRTDLL=1 
$(extra_include) $(AM_CPPFLAGS)
+libarm32_libmingw32_a_CFLAGS=-fno-builtin-fprintf $(AM_CFLAGS)
 libarm32_libmingw32_a_SOURCES = $(src_libmingw32)
 
 libarm32_LIBRARIES += libarm32/libmingwex.a
@@ -1465,6 +1468,7 @@ libarm64_liblargeint_a_CPPFLAGS=$(CPPFLAGSARM64) 
$(sysincludes)
 
 libarm64_LIBRARIES += libarm64/libmingw32.a
 libarm64_libmingw32_a_CPPFLAGS=$(CPPFLAGSARM64) -D_SYSCRT=1 -DCRTDLL=1 
$(extra_include) $(AM_CPPFLAGS)
+libarm64_libmingw32_a_CFLAGS=-fno-builtin-fprintf $(AM_CFLAGS)
 libarm64_libmingw32_a_SOURCES = $(src_libmingw32)
 
 libarm64_LIBRARIES += libarm64/libmingwex.a
diff --git a/mingw-w64-crt/crt/ucrtbase_compat.c 
b/mingw-w64-crt/crt/ucrtbase_compat.c
index 3d0fdbb..ca5381a 100644
--- a/mingw-w64-crt/crt/ucrtbase_compat.c
+++ b/mingw-w64-crt/crt/ucrtbase_compat.c
@@ -151,9 +151,7 @@ char ** __MINGW_IMP_SYMBOL(_wcmdln);
 // to work properly with ucrtbase.dll.
 #define _EXIT_LOCK1 8
 
-static int compat_inited;
 static CRITICAL_SECTION exit_lock;
-static size_t (*real_fwrite)(const void *restrict, size_t, size_t, FILE 
*restrict);
 static char * (*real_setlocale)(int, const char*);
 static wchar_t * (*real__wsetlocale)(int, const wchar_t*);
 static int local__mb_cur_max;
@@ -164,14 +162,11 @@ static void __cdecl free_locks(void)
   DeleteCriticalSection(_lock);
 }
 
-static void __cdecl init_compat(void)
+static void __cdecl init_compat_dtor(void)
 {
   HANDLE ucrt;
-  if (compat_inited)
-return;
 
   ucrt = GetModuleHandle("ucrtbase.dll");
-  real_fwrite = (size_t (*)(const void *restrict, size_t, size_t, FILE 
*restrict)) GetProcAddress(ucrt, "fwrite");
   real_setlocale = (char * (*)(int, const char*)) GetProcAddress(ucrt, 
"setlocale");
   real__wsetlocale = (wchar_t * (*)(int, const wchar_t*)) GetProcAddress(ucrt, 
"_wsetlocale");
 
@@ -179,16 +174,6 @@ static void __cdecl init_compat(void)
 
   local__mb_cur_max = ___mb_cur_max_func();
 
-  compat_inited = 1;
-}
-
-static void __cdecl init_compat_dtor(void)
-{
-  init_compat();
-  // atexit requires parts for this is inited at .CRT$XIAA, but we might need
-  // the compat init for fwrite (fprintf with a constant string) already in
-  // _pei386_runtime_relocator which for DLLs is run before the constructors
-  // in .CRT$XIAA.
   atexit(free_locks);
 }
 
@@ -203,8 +188,6 @@ _CRTALLOC(".CRT$XID") _PVFV mingw_ucrtbase_compat_init = 
init_compat_dtor;
 char * __cdecl setlocale(int _Category, const char *_Locale)
 {
   char *ret;
-  if (!compat_inited)
-init_compat();
   ret = real_setlocale(_Category, _Locale);
   local__mb_cur_max = ___mb_cur_max_func();
   return ret;
@@ -213,8 +196,6 @@ char * __cdecl setlocale(int _Category, const char *_Locale)
 wchar_t * __cdecl _wsetlocale(int _Category, const wchar_t *_Locale)
 {
   wchar_t *ret;
-  if (!compat_inited)
-init_compat();
   ret = real__wsetlocale(_Category, _Locale);
   local__mb_cur_max = ___mb_cur_max_func();
   return ret;
@@ -256,8 +237,6 @@ FILE *__cdecl __iob_func(void)
 // files.
 int __cdecl vfprintf(FILE *ptr, const char *fmt, va_list ap)
 {
-  if (!compat_inited)
-init_compat();
   if (ptr != _iob[2])
 abort();
   return real_vfprintf(stderr, fmt, ap);
@@ -267,8 +246,6 @@ int __cdecl fprintf(FILE *ptr, const char *fmt, ...)
 {
   va_list ap;
   int ret;
-  if