Update GN to master/95b0f8fe

Change-Id: I5847aa4859fb1cf5c9fc219693a1f5176fcbd7f9
Reviewed-on: https://codereview.qt-project.org/c/qt/qtwebengine-chromium/+/594459
Reviewed-by: Allan Sandfeld Jensen <[email protected]>

Author: Michal Klocek

gn/AUTHORS

@@ -21,6 +21,7 @@ Vewd Software AS <*@vewd.com>
 Vivaldi Technologies AS <*@vivaldi.com>
 Yandex LLC <*@yandex-team.ru>
 
+Aleksei Khoroshilov <[email protected]>
 Alexis Menard <[email protected]>
 Alfredo Mazzinghi <[email protected]>
 Andrew Boyarshin <[email protected]>

gn/README.md

@@ -13,7 +13,7 @@ Related resources:
        (all builtin help converted to a single file).
   * An introductory [presentation](https://docs.google.com/presentation/d/15Zwb53JcncHfEwHpnG_PoIbbzQ3GQi_cpujYwbpcbZo/edit?usp=sharing).
   * The [mailing list](https://groups.google.com/a/chromium.org/forum/#!forum/gn-dev).
-  * The [bug database](https://bugs.chromium.org/p/gn/issues/list).
+  * The [bug database](https://gn.issues.chromium.org/issues?q=status:open).
 
 ## What GN is for
 
@@ -107,6 +107,10 @@ On Linux, Mac and z/OS, the default compiler is `clang++`, a recent version is
 expected to be found in `PATH`. This can be overridden by setting the `CC`, `CXX`,
 and `AR` environment variables.
 
+On MSYS and MinGW, the default compiler is `g++`, a recent version is
+expected to be found in `PATH`. This can be overridden by setting the `CC`, `CXX`,
+`LD` and `AR` environment variables.
+
 On z/OS, building GN requires [ZOSLIB](https://github.com/ibmruntimes/zoslib) to be
 installed, as described at that URL. When building with `build/gen.py`, use the option
 `--zoslib-dir` to specify the path to [ZOSLIB](https://github.com/ibmruntimes/zoslib):

gn/build/build_linux.ninja.template

@@ -5,7 +5,7 @@ rule cxx
   deps = gcc
 
 rule alink_thin
-  command = rm -f $out && $ar rcsT $out $in
+  command = $ar rcsT $out $in
   description = AR $out
 
 rule link

gn/build/gen.py

@@ -101,7 +101,7 @@ def is_zos(self):
     return self._platform == 'zos'
 
   def is_serenity(self):
-    return self_.platform == 'serenity'
+    return self._platform == 'serenity'
 
 class ArgumentsList:
   """Helper class to accumulate ArgumentParser argument definitions
@@ -245,7 +245,7 @@ def GenerateLastCommitPosition(host, header):
   describe_output = subprocess.check_output(
       ['git', 'describe', 'HEAD', '--abbrev=12', '--match', ROOT_TAG],
       shell=host.is_windows(), cwd=REPO_ROOT)
-  mo = re.match(ROOT_TAG + '-(\d+)-g([0-9a-f]+)', describe_output.decode())
+  mo = re.match(ROOT_TAG + r'-(\d+)-g([0-9a-f]+)', describe_output.decode())
   if not mo:
     raise ValueError(
         'Unexpected output from git describe when generating version header')
@@ -317,7 +317,12 @@ def WriteGenericNinja(path, static_libraries, executables,
 
   if platform.is_windows():
     executable_ext = '.exe'
-    library_ext = '.lib'
+
+    if platform.is_msvc():
+      library_ext = '.lib'
+    else:
+      library_ext = '.a'
+
     object_ext = '.obj'
   else:
     executable_ext = ''
@@ -505,21 +510,16 @@ def WriteGNNinja(path, platform, host, options, args_list):
       if not options.no_static_libstdcpp:
         ldflags.append('-static-libstdc++')
 
-      if platform.is_mingw() or platform.is_msys():
-        cflags.remove('-std=c++20')
-        cflags.extend([
-          '-Wno-deprecated-copy',
-          '-Wno-implicit-fallthrough',
-          '-Wno-redundant-move',
-          '-Wno-unused-variable',
-          '-Wno-format',             # Use of %llx, which is supported by _UCRT, false positive
-          '-Wno-strict-aliasing',    # Dereferencing punned pointer
-          '-Wno-cast-function-type', # Casting FARPROC to RegDeleteKeyExPtr
-          '-std=gnu++20',
-        ])
-      else:
-        # This is needed by libc++.
-        libs.append('-ldl')
+      cflags.extend([
+        '-Wno-deprecated-copy',
+        '-Wno-implicit-fallthrough',
+        '-Wno-redundant-move',
+        '-Wno-unused-variable',
+        '-Wno-format',             # Use of %llx, which is supported by _UCRT, false positive
+        '-Wno-strict-aliasing',    # Dereferencing punned pointer
+        '-Wno-cast-function-type', # Casting FARPROC to RegDeleteKeyExPtr
+      ])
+
     elif platform.is_darwin():
       min_mac_version_flag = '-mmacosx-version-min=10.9'
       cflags.append(min_mac_version_flag)

gn/docs/mingw.md

@@ -0,0 +1,34 @@
+# Building and using `gn` with MinGW on Windows
+
+At the time of writing: 2024-04-13
+Test environment: Windows 11, intel x86_64 CPU
+
+## Requirements
+
+1.  Install [MSYS2](https://www.msys2.org/)
+1.  Start a Terminal windows for MSYS2's MinGW development by opening one of `clang32.exe`, `clang64.exe`, `clangarm64.exe`,`mingw32.exe`, `mingw64.exe`, `ucrt64.exe`.
+1.  To download clang toolchain, Ninja and git programs, run command: `pacman -S mingw-w64-clang-x86_64-toolchain mingw-w64-clang-x86_64-ninja git`
+
+## Build `gn`
+
+1.  To clone `gn` source code, run command: `git clone https://gn.googlesource.com/gn`
+1.  Run command: `cd gn`
+1.  Run command: `build/gen.py --platform mingw`  
+    This configuration generates a static executable that does not depend on MSYS2, and can be run in any development environment.  
+    Use `--help` flag to check more configuration options.  
+    Use `--allow-warning` flag to build with warnings.
+1.  Run command: `ninja -C out`
+
+## Testing
+
+1.  Run command: `out/gn --version`
+1.  Run command: `out/gn_unittests`
+
+> Notes:
+>
+> For "mingw-w64-clang-x86_64-toolchain" in the clang64 environment, g++ is a copy of clang++.
+>
+> The toolchain that builds `gn` does not use vendor lock-in compiler command flags,
+> so `gn` can be built with these clang++, g++.
+>
+> However the build rules in [examples/simple_build](../examples/simple_build/) require GCC-specific compiler macros, and thus only work in the `ucrt64` MSYS2 development environment.