msvc: support building Git using MS Visual C++

With this patch, Git can be built using the Microsoft toolchain, via:

	make MSVC=1 [DEBUG=1]

Third party libraries are built from source using the open source
"vcpkg" tool set. See https://github.com/Microsoft/vcpkg

On a first build, the vcpkg tools and the third party libraries are
automatically downloaded and built. DLLs for the third party libraries
are copied to the top-level (and t/helper) directory to facilitate
debugging. See compat/vcbuild/README.

A series of .bat files are invoked by the Makefile to find the location
of the installed version of Visual Studio and the associated compiler
tools (essentially replicating the environment setup performed by a
"Developer Command Prompt"). This should find the most recent VS2015 or
VS2017 installation. Output from these scripts are used by the Makefile
to define compiler and linker pathnames and -I and -L arguments.

The build produces .pdb files for both debug and release builds.

Note: This commit was squashed from an organic series of commits
developed between 2016 and 2018 in Git for Windows' `master` branch.
This combined commit eliminates the obsolete commits related to fetching
NuGet packages for third party libraries. It is difficult to use NuGet
packages for C/C++ sources because they may be built by earlier versions
of the MSVC compiler and have CRT version and linking issues.

Additionally, the C/C++ NuGet packages that we were using tended to not
be updated concurrently with the sources.  And in the case of cURL and
OpenSSL, this could expose us to security issues.

Helped-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Helped-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 62 insertions, 10 deletions

diff --git a/config.mak.uname b/config.mak.uname
index 473613a20d..b8c52e49d2 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -1,5 +1,9 @@
 # Platform specific Makefile tweaks based on uname detection
 
+# Define NO_SAFESEH if you need MSVC/Visual Studio to ignore the lack of
+# Microsoft's Safe Exception Handling in libraries (such as zlib).
+# Typically required for VS2013+/32-bit compilation on Vista+ versions.
+
 uname_S := $(shell sh -c 'uname -s 2>/dev/null || echo not')
 uname_M := $(shell sh -c 'uname -m 2>/dev/null || echo not')
 uname_O := $(shell sh -c 'uname -o 2>/dev/null || echo not')
@@ -11,6 +15,19 @@ ifdef MSVC
 	# avoid the MingW and Cygwin configuration sections
 	uname_S := Windows
 	uname_O := Windows
+
+	# Generate and include makefile variables that point to the
+	# currently installed set of MSVC command line tools.
+compat/vcbuild/MSVC-DEFS-GEN: compat/vcbuild/find_vs_env.bat
+	@"$<" | tr '\\' / >"$@"
+include compat/vcbuild/MSVC-DEFS-GEN
+
+	# See if vcpkg and the vcpkg-build versions of the third-party
+	# libraries that we use are installed.  We include the result
+	# to get $(vcpkg_*) variables defined for the Makefile.
+compat/vcbuild/VCPKG-DEFS: compat/vcbuild/vcpkg_install.bat
+	@"$<"
+include compat/vcbuild/VCPKG-DEFS
 endif
 
 # We choose to avoid "if .. else if .. else .. endif endif"
@@ -356,6 +373,19 @@ endif
 ifeq ($(uname_S),Windows)
 	GIT_VERSION := $(GIT_VERSION).MSVC
 	pathsep = ;
+	# Assume that this is built in Git for Windows' SDK
+	ifeq (MINGW32,$(MSYSTEM))
+		prefix = /mingw32
+	else
+		prefix = /mingw64
+	endif
+	# Prepend MSVC 64-bit tool-chain to PATH.
+	#
+	# A regular Git Bash *does not* have cl.exe in its $PATH. As there is a
+	# link.exe next to, and required by, cl.exe, we have to prepend this
+	# onto the existing $PATH.
+	#
+	SANE_TOOL_PATH ?= $(msvc_bin_dir_msys)
 	HAVE_ALLOCA_H = YesPlease
 	NO_PREAD = YesPlease
 	NEEDS_CRYPTO_WITH_SSL = YesPlease
@@ -368,11 +398,14 @@ ifeq ($(uname_S),Windows)
 	NO_STRCASESTR = YesPlease
 	NO_STRLCPY = YesPlease
 	NO_MEMMEM = YesPlease
-	# NEEDS_LIBICONV = YesPlease
-	NO_ICONV = YesPlease
+	NEEDS_LIBICONV = YesPlease
 	NO_STRTOUMAX = YesPlease
 	NO_MKDTEMP = YesPlease
-	SNPRINTF_RETURNS_BOGUS = YesPlease
+	NO_INTTYPES_H = YesPlease
+	# VS2015 with UCRT claims that snprintf and friends are C99 compliant,
+	# so we don't need this:
+	#
+	#   SNPRINTF_RETURNS_BOGUS = YesPlease
 	NO_SVN_TESTS = YesPlease
 	RUNTIME_PREFIX = YesPlease
 	HAVE_WPGMPTR = YesWeDo
@@ -385,7 +418,6 @@ ifeq ($(uname_S),Windows)
 	NO_REGEX = YesPlease
 	NO_GETTEXT = YesPlease
 	NO_PYTHON = YesPlease
-	BLK_SHA1 = YesPlease
 	ETAGS_TARGET = ETAGS
 	NO_POSIX_GOODIES = UnfortunatelyYes
 	NATIVE_CRLF = YesPlease
@@ -394,24 +426,44 @@ ifeq ($(uname_S),Windows)
 	CC = compat/vcbuild/scripts/clink.pl
 	AR = compat/vcbuild/scripts/lib.pl
 	CFLAGS =
-	BASIC_CFLAGS = -nologo -I. -I../zlib -Icompat/vcbuild -Icompat/vcbuild/include -DWIN32 -D_CONSOLE -DHAVE_STRING_H -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_DEPRECATE
+	BASIC_CFLAGS = -nologo -I. -Icompat/vcbuild/include -DWIN32 -D_CONSOLE -DHAVE_STRING_H -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_DEPRECATE
 	COMPAT_OBJS = compat/msvc.o compat/winansi.o \
 		compat/win32/path-utils.o \
 		compat/win32/pthread.o compat/win32/syslog.o \
 		compat/win32/trace2_win32_process_info.o \
 		compat/win32/dirent.o
-	COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DNOGDI -DHAVE_STRING_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\"
+	COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DDETECT_MSYS_TTY -DNOGDI -DHAVE_STRING_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\"
 	BASIC_LDFLAGS = -IGNORE:4217 -IGNORE:4049 -NOLOGO -ENTRY:wmainCRTStartup -SUBSYSTEM:CONSOLE
-	EXTLIBS = user32.lib advapi32.lib shell32.lib wininet.lib ws2_32.lib invalidcontinue.obj
+	# invalidcontinue.obj allows Git's source code to close the same file
+	# handle twice, or to access the osfhandle of an already-closed stdout
+	# See https://msdn.microsoft.com/en-us/library/ms235330.aspx
+	EXTLIBS = user32.lib advapi32.lib shell32.lib wininet.lib ws2_32.lib invalidcontinue.obj kernel32.lib ntdll.lib
 	PTHREAD_LIBS =
 	lib =
+	BASIC_CFLAGS += $(vcpkg_inc) $(sdk_includes) $(msvc_includes)
+ifndef DEBUG
+	BASIC_CFLAGS += $(vcpkg_rel_lib)
+else
+	BASIC_CFLAGS += $(vcpkg_dbg_lib)
+endif
+	BASIC_CFLAGS += $(sdk_libs) $(msvc_libs)
+
 	BASIC_CFLAGS += -DPROTECT_NTFS_DEFAULT=1
+	# Always give "-Zi" to the compiler and "-debug" to linker (even in
+	# release mode) to force a PDB to be generated (like RelWithDebInfo).
+	BASIC_CFLAGS += -Zi
+	BASIC_LDFLAGS += -debug -Zf
+
+ifdef NO_SAFESEH
+	LDFLAGS += -SAFESEH:NO
+endif
+
 ifndef DEBUG
-	BASIC_CFLAGS += -GL -Os -MD
-	BASIC_LDFLAGS += -LTCG
+	BASIC_CFLAGS += -GL -Gy -O2 -Oy- -MD -DNDEBUG
+	BASIC_LDFLAGS += -release -LTCG /OPT:REF /OPT:ICF /INCREMENTAL:NO /DEBUGTYPE:CV,FIXUP
 	AR += -LTCG
 else
-	BASIC_CFLAGS += -Zi -MDd
+	BASIC_CFLAGS += -MDd -DDEBUG -D_DEBUG
 endif
 	X = .exe