Hi Martin,
The idea of a separated crt library for UWP seems reasonable to be. It
could also potentially help with some other UWP compatibility problems.
Having to implement a number of string functions is not really optimal,
but it looks like we need it. Long term, as we discussed lately, we may
have a possibility to use Wine for that. Once Wine has proper msvcrt
implementation in a PE file, it should be possible to extract that and
provide a static msvcrt/ucrt library.
Anyway, I'm fine with the patch.
Thanks,
Jacek
On 05.06.2020 14:59, Martin Storsjö wrote:
This adds libucrtapp.a, which is the same as libucrt.a, but excluding
libapi-ms-win-crt-private-l1-1-0.a, and with a few statically
linked functions added that otherwise normally are linked from
libapi-ms-win-crt-private-l1-1-0.a.
Linking against the private dll (and ucrtbase.dll) is prohibited when
targeting UWP. An app built and packaged with MSVC would link against
these functions from vcruntime140_app.dll, which ends up bundled with
the app itself. However, the goal of this patch is to make it possible
to build a UWP app with mingw tools and redistribute it without bundling
vcruntime140_app.dll or similar ones from MSVC.
By using a separate copy of libucrt*.a, without the forbidden bits, it
gives a clear linker error if an app requires linking against other
functions that aren't implemented yet, instead of silently ending up
depending on the forbidden api-ms-win-crt-private-l1-1-0.dll.
The functions from this DLL, that end up linked in a mingw build,
are primarily one of the these four areas:
- __C_specific_handler
The implementation so far is a dummy; wine should have a suitable
proper implementation for reference. This shouldn't matter much, except
potentially for turning unhandled exceptions into signals (but that
might also be handled via a different mechanism).
- setjmp/longjmp
The implementation should be ok, but doesn't do a SEH unwind (yet) but
just a plain longjmp. A full implementation should be doable, but is
not really needed for mingw code.
- string functions: memcpy and memmove
Added minimal wrappers that just call memcpy_s and memmove_s from
api-ms-win-crt-string-l1-1-0.dll, as that one should have implementations
with good performance.
- string functions: memchr, memcmp, strchr, strrchr, strstr, wcschr, wcsrchr,
wcsstr
These are copied from musl (with minor modifications to make them
compile in mingw-w64, and with an added copyright header).
By naming the library libucrtapp.a, clang users can choose to link
against this by passing -lucrtapp (which makes clang omit the default
-lmsvcrt, which would be equal to libucrt.a in such a case).
Signed-off-by: Martin Storsjö
---
mingw-w64-crt/Makefile.am| 53 ++-
mingw-w64-crt/crt/__C_specific_handler.c | 34 +
mingw-w64-crt/lib-common/ucrtapp.mri | 19 +++
mingw-w64-crt/misc/longjmp.S | 97 +
mingw-w64-crt/misc/setjmp.S | 115 +++
mingw-w64-crt/string/memchr.c| 50 +++
mingw-w64-crt/string/memcmp.c| 31
mingw-w64-crt/string/memcpy.c| 12 ++
mingw-w64-crt/string/memmove.c | 12 ++
mingw-w64-crt/string/memrchr.c | 34 +
mingw-w64-crt/string/strchr.c| 32
mingw-w64-crt/string/strchrnul.c | 51 +++
mingw-w64-crt/string/strrchr.c | 31
mingw-w64-crt/string/strstr.c| 177 +++
mingw-w64-crt/string/wcschr.c| 31
mingw-w64-crt/string/wcsrchr.c | 31
mingw-w64-crt/string/wcsstr.c| 128
17 files changed, 930 insertions(+), 8 deletions(-)
create mode 100644 mingw-w64-crt/crt/__C_specific_handler.c
create mode 100644 mingw-w64-crt/lib-common/ucrtapp.mri
create mode 100644 mingw-w64-crt/misc/longjmp.S
create mode 100644 mingw-w64-crt/misc/setjmp.S
create mode 100644 mingw-w64-crt/string/memchr.c
create mode 100644 mingw-w64-crt/string/memcmp.c
create mode 100644 mingw-w64-crt/string/memcpy.c
create mode 100644 mingw-w64-crt/string/memmove.c
create mode 100644 mingw-w64-crt/string/memrchr.c
create mode 100644 mingw-w64-crt/string/strchr.c
create mode 100644 mingw-w64-crt/string/strchrnul.c
create mode 100644 mingw-w64-crt/string/strrchr.c
create mode 100644 mingw-w64-crt/string/strstr.c
create mode 100644 mingw-w64-crt/string/wcschr.c
create mode 100644 mingw-w64-crt/string/wcsrchr.c
create mode 100644 mingw-w64-crt/string/wcsstr.c
diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index c30e22cce..b104da3a1 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -241,6 +241,23 @@ src_ucrtbase=\
stdio/ucrt_vsnprintf.c \
stdio/ucrt_vsprintf.c
+src_ucrtapp=\
+ crt/__C_specific_handler.c \
+ misc/longjmp.S \
+ misc/setjmp.S \
+ string/memchr.c \
+
