Skip to content

Add MSVC precompiled header support #5301

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
randombit merged 2 commits into from
Feb 8, 2026
Merged

Add MSVC precompiled header support #5301

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a227c62
Initial plan
Copilot Feb 8, 2026
eb06713
Add MSVC PCH support with stub .cpp files
Copilot Feb 8, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
30 changes: 27 additions & 3 deletions configure.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2382,20 +2382,37 @@ def test_exe_extra_ldflags():
}

if variables['enable_pch']:
variables['pch_include_for_lib'] = '%s %s' % (cc.pch_include, os.path.join(build_paths.pch_dir, 'pch_lib.h'))
variables['pch_path_for_lib'] = os.path.join(build_paths.pch_dir, 'pch_lib.h.' + cc.pch_suffix)

variables['pch_include_for_exe'] = '%s %s' % (cc.pch_include, os.path.join(build_paths.pch_dir, 'pch_exe.h'))
variables['pch_path_for_exe'] = os.path.join(build_paths.pch_dir, 'pch_exe.h.' + cc.pch_suffix)

variables['pch_target'] = 'pch'
variables['is_msvc'] = cc.macro_name == 'MSVC'

if cc.macro_name == 'MSVC':
# MSVC requires compiling a .cpp file and using /Fp to specify output
variables['pch_src_for_lib'] = os.path.join(build_paths.pch_dir, 'pch_lib.cpp')
variables['pch_src_for_exe'] = os.path.join(build_paths.pch_dir, 'pch_exe.cpp')
variables['pch_compile_for_lib'] = '/Ycpch_lib.h /Fp%s' % variables['pch_path_for_lib']
variables['pch_compile_for_exe'] = '/Ycpch_exe.h /Fp%s' % variables['pch_path_for_exe']
# MSVC uses /Yu to use PCH and /Fp to specify which one, and /FI to force include
variables['pch_include_for_lib'] = '/Yupch_lib.h /Fp%s /FIpch_lib.h' % variables['pch_path_for_lib']
variables['pch_include_for_exe'] = '/Yupch_exe.h /Fp%s /FIpch_exe.h' % variables['pch_path_for_exe']
else:
# GCC/Clang compile the header directly
variables['pch_src_for_lib'] = os.path.join(build_paths.pch_dir, 'pch_lib.h')
variables['pch_src_for_exe'] = os.path.join(build_paths.pch_dir, 'pch_exe.h')
variables['pch_compile_for_lib'] = cc.pch_compile
variables['pch_compile_for_exe'] = cc.pch_compile
variables['pch_include_for_lib'] = '%s %s' % (cc.pch_include, os.path.join(build_paths.pch_dir, 'pch_lib.h'))
variables['pch_include_for_exe'] = '%s %s' % (cc.pch_include, os.path.join(build_paths.pch_dir, 'pch_exe.h'))
else:
variables['pch_include_for_lib'] = ''
variables['pch_path_for_lib'] = ''
variables['pch_include_for_exe'] = ''
variables['pch_path_for_exe'] = ''

variables['pch_target'] = ''
variables['is_msvc'] = False

variables['installed_include_dir'] = os.path.join(
variables['prefix'],
Expand Down Expand Up @@ -3554,6 +3571,13 @@ def in_build_module_info(p):
if options.enable_pch:
shutil.copy(in_src_lib_dir('pch/pch.h'), os.path.join(build_paths.pch_dir, 'pch_lib.h'))
shutil.copy(in_src_lib_dir('pch/pch.h'), os.path.join(build_paths.pch_dir, 'pch_exe.h'))

# MSVC requires a .cpp file to compile the PCH
if template_vars['cc_macro'] == 'MSVC':
with open(os.path.join(build_paths.pch_dir, 'pch_lib.cpp'), 'w', encoding='utf8') as f:
f.write('#include "pch_lib.h"\n')
with open(os.path.join(build_paths.pch_dir, 'pch_exe.cpp'), 'w', encoding='utf8') as f:
f.write('#include "pch_exe.h"\n')

def link_headers(headers, visibility, directory):
logging.debug('Linking %d %s header files in %s', len(headers), visibility, directory)
Expand Down
4 changes: 4 additions & 0 deletions src/build-data/cc/msvc.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,10 @@ add_lib_option "%s.lib"

compile_flags "/nologo /c"

pch_compile "/Yc"
pch_suffix "pch"
pch_include "/Yu"

optimization_flags "/O2 /Oi /Zc:throwingNew"
size_optimization_flags "/O1 /Os"

Expand Down
8 changes: 4 additions & 4 deletions src/build-data/makefile.in
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -53,11 +53,11 @@ docs: %{doc_stamp_file}

%{if enable_pch}

%{pch_path_for_lib}: %{pch_dir}/pch_lib.h
$(CXX) $(LIB_FLAGS) $(BUILD_FLAGS) -DBOTAN_IS_BEING_BUILT %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile} %{dash_c} %{pch_dir}/pch_lib.h %{dash_o}$@
%{pch_path_for_lib}: %{pch_src_for_lib}
$(CXX) $(LIB_FLAGS) $(BUILD_FLAGS) -DBOTAN_IS_BEING_BUILT %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile_for_lib} %{dash_c} %{pch_src_for_lib} %{dash_o}$@

%{pch_path_for_exe}: %{pch_dir}/pch_exe.h
$(CXX) $(BUILD_FLAGS) -DBOTAN_IS_BEING_BUILT %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile} %{dash_c} %{pch_dir}/pch_exe.h %{dash_o}$@
%{pch_path_for_exe}: %{pch_src_for_exe}
$(CXX) $(BUILD_FLAGS) -DBOTAN_IS_BEING_BUILT %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile_for_exe} %{dash_c} %{pch_src_for_exe} %{dash_o}$@

%{endif}

Expand Down
8 changes: 4 additions & 4 deletions src/build-data/ninja.in
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,14 +23,14 @@ INSTALLED_LIB_DIR = %{libdir}

%{if enable_pch}
rule compile_pch_lib
command = %{cxx} %{lib_flags} ${ABI_FLAGS} ${LANG_FLAGS} ${CXXFLAGS} -DBOTAN_IS_BEING_BUILT ${WARN_FLAGS} %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile} %{dash_c} $in %{dash_o}$out
command = %{cxx} %{lib_flags} ${ABI_FLAGS} ${LANG_FLAGS} ${CXXFLAGS} -DBOTAN_IS_BEING_BUILT ${WARN_FLAGS} %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile_for_lib} %{dash_c} $in %{dash_o}$out

rule compile_pch_exe
command = %{cxx} ${ABI_FLAGS} ${LANG_FLAGS} ${CXXFLAGS} -DBOTAN_IS_BEING_BUILT ${WARN_FLAGS} %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile} %{dash_c} $in %{dash_o}$out
command = %{cxx} ${ABI_FLAGS} ${LANG_FLAGS} ${CXXFLAGS} -DBOTAN_IS_BEING_BUILT ${WARN_FLAGS} %{public_include_flags} %{internal_include_flags} %{external_include_flags} %{pch_compile_for_exe} %{dash_c} $in %{dash_o}$out

build %{pch_path_for_lib}: compile_pch_lib %{pch_dir}/pch_lib.h
build %{pch_path_for_lib}: compile_pch_lib %{pch_src_for_lib}

build %{pch_path_for_exe}: compile_pch_exe %{pch_dir}/pch_exe.h
build %{pch_path_for_exe}: compile_pch_exe %{pch_src_for_exe}

%{endif}

Expand Down