refactor gcc module infrastructure

1 files changed, 0 insertions, 622 deletions

diff --git a/xmake/rules/c++/modules/modules_support/gcc.lua b/xmake/rules/c++/modules/modules_support/gcc.lua
deleted file mode 100644
index 6cc5c29d6..000000000
--- a/xmake/rules/c++/modules/modules_support/gcc.lua
+++ /dev/null
@@ -1,622 +0,0 @@
---!A cross-platform build utility based on Lua
---
--- Licensed under the Apache License, Version 2.0 (the "License");
--- you may not use this file except in compliance with the License.
--- You may obtain a copy of the License at
---
---     http://www.apache.org/licenses/LICENSE-2.0
---
--- Unless required by applicable law or agreed to in writing, software
--- distributed under the License is distributed on an "AS IS" BASIS,
--- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
--- See the License for the specific language governing permissions and
--- limitations under the License.
---
--- Copyright (C) 2015-present, TBOOX Open Source Group.
---
--- @author      ruki
--- @file        gcc.lua
---
-
--- imports
-import("core.base.option")
-import("core.base.json")
-import("core.tool.compiler")
-import("core.project.project")
-import("core.project.depend")
-import("core.project.config")
-import("utils.progress")
-import("private.action.build.object", {alias = "objectbuilder"})
-import("common")
-
--- get and create the path of module mapper
-function _get_module_mapper(target)
-    local mapper_file = path.join(config.buildir(), target:name(), "mapper.txt")
-    if not os.isfile(mapper_file) then
-        io.writefile(mapper_file, "")
-    end
-    return mapper_file
-end
-
--- add a module or header unit into the mapper
---
--- e.g
--- /usr/include/c++/11/iostream build/.gens/stl_headerunit/linux/x86_64/release/stlmodules/cache/iostream.gcm
--- hello build/.gens/stl_headerunit/linux/x86_64/release/rules/modules/cache/hello.gcm
---
-function _add_module_to_mapper(file, modulepath, bmi)
-    for line in io.lines(file) do
-        if line:startswith(modulepath .. " ") then
-            return false
-        end
-    end
-    local f = io.open(file, "a")
-    f:print("%s %s", modulepath, bmi)
-    f:close()
-    return true
-end
-
--- get a module from mapper
-function _get_module_from_mapper(file, module)
-    for line in io.lines(file) do
-        if line:startswith(module .. " ") then
-            return line:split(" ", {plain = true})
-        end
-    end
-end
-
--- load module support for the current target
-function load(target)
-    local modulesflag = get_modulesflag(target)
-    local modulemapperflag = get_modulemapperflag(target)
-    if os.isfile(_get_module_mapper(target)) then
-        os.rm(_get_module_mapper(target))
-    end
-    target:add("cxxflags", {modulesflag, modulemapperflag .. path.translate(_get_module_mapper(target))}, {force = true, expand = false})
-    -- fix cxxabi issue
-    -- @see https://github.com/xmake-io/xmake/issues/2716#issuecomment-1225057760
-    -- https://github.com/xmake-io/xmake/issues/3855
-    if target:policy("build.c++.gcc.modules.cxx11abi") then
-        target:add("cxxflags", "-D_GLIBCXX_USE_CXX11_ABI=1")
-    else
-        target:add("cxxflags", "-D_GLIBCXX_USE_CXX11_ABI=0")
-    end
-end
-
--- get includedirs for stl headers
---
--- $ echo '#include <vector>' | gcc -x c++ -E - | grep '/vector"'
--- # 1 "/usr/include/c++/11/vector" 1 3
--- # 58 "/usr/include/c++/11/vector" 3
--- # 59 "/usr/include/c++/11/vector" 3
---
-function _get_toolchain_includedirs_for_stlheaders(includedirs, gcc)
-    local tmpfile = os.tmpfile() .. ".cc"
-    io.writefile(tmpfile, "#include <vector>")
-    local result = try {function () return os.iorunv(gcc, {"-E", "-x", "c++", tmpfile}) end}
-    if result then
-        for _, line in ipairs(result:split("\n", {plain = true})) do
-            line = line:trim()
-            if line:startswith("#") and line:find("/vector\"", 1, true) then
-                local includedir = line:match("\"(.+)/vector\"")
-                if includedir and os.isdir(includedir) then
-                    table.insert(includedirs, path.normalize(includedir))
-                    break
-                end
-            end
-        end
-    end
-    os.tryrm(tmpfile)
-end
-
--- do compile for batchcmds
--- @note we need to use batchcmds:compilev to translate paths in compflags for generator, e.g. -Ixx
-function _batchcmds_compile(batchcmds, target, flags, sourcefile)
-    local compinst = target:compiler("cxx")
-    local compflags = compinst:compflags({sourcefile = sourcefile, target = target})
-    batchcmds:compilev(table.join(compflags or {}, flags), {compiler = compinst, sourcekind = "cxx"})
-end
-
--- build module file
-function _build_modulefile(target, sourcefile, opt)
-    local objectfile = opt.objectfile
-    local dependfile = opt.dependfile
-    local compinst = compiler.load("cxx", {target = target})
-    local compflags = table.join("-x", "c++", compinst:compflags({sourcefile = sourcefile, target = target}))
-    local dependinfo = target:is_rebuilt() and {} or (depend.load(dependfile, {target = target}) or {})
-
-    -- need build this object?
-    local dryrun = option.get("dry-run")
-    local depvalues = {compinst:program(), compflags}
-    local lastmtime = os.isfile(objectfile) and os.mtime(dependfile) or 0
-    if not dryrun and not depend.is_changed(dependinfo, {lastmtime = lastmtime, values = depvalues}) then
-        return
-    end
-
-    -- trace
-    progress.show(opt.progress, "${color.build.object}compiling.module.$(mode) %s", opt.name)
-    vprint(compinst:compcmd(sourcefile, objectfile, {compflags = compflags, rawargs = true}))
-
-    if not dryrun then
-
-        -- do compile
-        dependinfo.files = {}
-        assert(compinst:compile(sourcefile, objectfile, {dependinfo = dependinfo, compflags = compflags}))
-
-        -- update files and values to the dependent file
-        dependinfo.values = depvalues
-        table.join2(dependinfo.files, sourcefile)
-        depend.save(dependinfo, dependfile)
-    end
-end
-
--- provide toolchain include directories for stl headerunit when p1689 is not supported
-function toolchain_includedirs(target)
-    local includedirs = _g.includedirs
-    if includedirs == nil then
-        includedirs = {}
-        local gcc, toolname = target:tool("cxx")
-        assert(toolname == "gcc")
-        _get_toolchain_includedirs_for_stlheaders(includedirs, gcc)
-        local _, result = try {function () return os.iorunv(gcc, {"-E", "-Wp,-v", "-xc", os.nuldev()}) end}
-        if result then
-            for _, line in ipairs(result:split("\n", {plain = true})) do
-                line = line:trim()
-                if os.isdir(line) then
-                    table.insert(includedirs, path.normalize(line))
-                elseif line:startswith("End") then
-                    break
-                end
-            end
-        end
-        _g.includedirs = includedirs
-    end
-    return includedirs
-end
-
--- generate dependency files
-function generate_dependencies(target, sourcebatch, opt)
-    local compinst = target:compiler("cxx")
-    local common_args = {"-E", "-x", "c++"}
-    local depformatflag = get_depflag(target, "p1689r5") or get_depflag(target, "trtbd")
-    local depfileflag = get_depfileflag(target)
-    local depoutputflag = get_depoutputflag(target)
-    local changed = false
-    for _, sourcefile in ipairs(sourcebatch.sourcefiles) do
-        local dependfile = target:dependfile(sourcefile)
-        depend.on_changed(function()
-            if opt.progress then
-                progress.show(opt.progress, "${color.build.object}generating.module.deps %s", sourcefile)
-            end
-
-            local outputdir = common.get_outputdir(target, sourcefile)
-            local jsonfile = path.translate(path.join(outputdir, path.filename(sourcefile) .. ".json"))
-            if depformatflag and depfileflag and depoutputflag and not target:policy("build.c++.gcc.fallbackscanner") then
-                local ifile = path.translate(path.join(outputdir, path.filename(sourcefile) .. ".i"))
-                local dfile = path.translate(path.join(outputdir, path.filename(sourcefile) .. ".d"))
-                local args = {sourcefile, "-MT", jsonfile, "-MD", "-MF", dfile, depformatflag, depfileflag .. jsonfile, depoutputflag .. target:objectfile(sourcefile), "-o", ifile}
-                local compflags = compinst:compflags({sourcefile = sourcefile, target = target})
-                -- module mapper flag force gcc to check the imports but this is not wanted at this stage
-                local modulemapperflag = get_modulemapperflag(target) .. path.translate(_get_module_mapper(target))
-                table.remove(compflags, table.unpack(table.find(compflags, modulemapperflag)))
-                os.vrunv(compinst:program(), table.join(compflags, common_args, args))
-                os.rm(ifile)
-                os.rm(dfile)
-            else
-                common.fallback_generate_dependencies(target, jsonfile, sourcefile, function(file)
-                    local compinst = target:compiler("cxx")
-                    local compflags = compinst:compflags({sourcefile = file, target = target})
-                    -- exclude -fmodule* flags because, when they are set gcc try to find bmi of imported modules but they don't exists a this point of compilation
-                    table.remove_if(compflags, function(_, flag) return flag:startswith("-fmodule") end)
-                    local ifile = path.translate(path.join(outputdir, path.filename(file) .. ".i"))
-                    os.vrunv(compinst:program(), table.join(common_args, compflags, {file,  "-o", ifile}))
-                    local content = io.readfile(ifile)
-                    os.rm(ifile)
-                    return content
-                end)
-            end
-            changed = true
-
-            local dependinfo = io.readfile(jsonfile)
-            return { moduleinfo = dependinfo }
-        end, {dependfile = dependfile, files = {sourcefile}, changed = target:is_rebuilt()})
-    end
-    return changed
-end
-
--- generate target stl header units for batchjobs
-function generate_stl_headerunits_for_batchjobs(target, batchjobs, headerunits, opt)
-    local compinst = target:compiler("cxx")
-    local mapper_file = _get_module_mapper(target)
-    local stlcachedir = common.stlmodules_cachedir(target, {mkdir = true})
-    local modulemapperflag = get_modulemapperflag(target)
-
-    -- build headerunits
-    local projectdir = os.projectdir()
-    for _, headerunit in ipairs(headerunits) do
-        local bmifile = path.join(stlcachedir, headerunit.name .. get_bmi_extension())
-        if not os.isfile(bmifile) then
-            batchjobs:addjob(headerunit.name, function (index, total)
-                depend.on_changed(function()
-                    progress.show((index * 100) / total, "${color.build.object}compiling.headerunit.$(mode) %s", headerunit.name)
-                    local args = {"-c", "-x", "c++-system-header", headerunit.name}
-                    local flags = table.join(compinst:compflags({target = target}), args)
-                    -- we need to support reading and writing mapperfile in parallel, otherwise it will be broken
-                    -- @see tests/c++/modules/stl_headerunit_cpp_only
-                    local mapper_file_tmp = os.tmpfile()
-                    os.cp(mapper_file, mapper_file_tmp)
-                    _add_module_to_mapper(mapper_file_tmp, headerunit.path, path.absolute(bmifile, projectdir))
-                    for idx, flag in ipairs(flags) do
-                        if flag:startswith(modulemapperflag) then
-                            flags[idx] = modulemapperflag .. mapper_file_tmp
-                            break
-                        end
-                    end
-                    os.vrunv(compinst:program(), flags)
-                    _add_module_to_mapper(mapper_file, headerunit.path, path.absolute(bmifile, projectdir))
-                    os.tryrm(mapper_file_tmp)
-                end, {dependfile = target:dependfile(bmifile), files = {headerunit.path}, changed = target:is_rebuilt()})
-            end, {rootjob = opt.rootjob})
-        else
-            _add_module_to_mapper(mapper_file, headerunit.path, path.absolute(bmifile, projectdir))
-        end
-    end
-end
-
--- generate target stl header units for batchcmds
-function generate_stl_headerunits_for_batchcmds(target, batchcmds, headerunits, opt)
-    local mapper_file = _get_module_mapper(target)
-    local stlcachedir = common.stlmodules_cachedir(target, {mkdir = true})
-
-    -- build headerunits
-    local projectdir = os.projectdir()
-    local depmtime = 0
-    for _, headerunit in ipairs(headerunits) do
-        local bmifile = path.join(stlcachedir, headerunit.name .. get_bmi_extension())
-        if not os.isfile(bmifile) then
-            local flags = {"-c", "-x", "c++-system-header", headerunit.name}
-            batchcmds:show_progress(opt.progress, "${color.build.object}compiling.headerunit.$(mode) %s", headerunit.name)
-            _batchcmds_compile(batchcmds, target, flags)
-        end
-        batchcmds:add_depfiles(headerunit.path)
-        _add_module_to_mapper(mapper_file, headerunit.path, path.absolute(bmifile, projectdir))
-        depmtime = math.max(depmtime, os.mtime(bmifile))
-    end
-    batchcmds:set_depmtime(depmtime)
-end
-
--- generate target user header units for batchjobs
-function generate_user_headerunits_for_batchjobs(target, batchjobs, headerunits, opt)
-    local compinst = target:compiler("cxx")
-    local mapper_file = _get_module_mapper(target)
-
-    -- build headerunits
-    local projectdir = os.projectdir()
-    for _, headerunit in ipairs(headerunits) do
-        local headerunit_path
-        if headerunit.type == ":quote" then
-            headerunit_path = path.join(".", path.relative(headerunit.path, projectdir))
-        elseif headerunit.type == ":angle" then
-            -- if path is relative then its a subtarget path
-            headerunit_path = path.is_absolute(headerunit.path) and headerunit.path or path.join(".", headerunit.path)
-        end
-        local objectfile = target:objectfile(headerunit_path)
-        local outputdir = common.get_outputdir(target, headerunit.path)
-        local bmifilename = path.basename(objectfile) .. get_bmi_extension()
-        local bmifile = path.join(outputdir, bmifilename)
-        batchjobs:addjob(headerunit.name, function (index, total)
-            depend.on_changed(function()
-                progress.show((index * 100) / total, "${color.build.object}compiling.headerunit.$(mode) %s", headerunit.name)
-                local objectdir = path.directory(objectfile)
-                if not os.isdir(objectdir) then
-                    os.mkdir(objectdir)
-                end
-
-                -- generate headerunit
-                local args = { "-c" }
-                if headerunit.type == ":quote" then
-                    local includedir
-                    local p = headerunit.path
-                    if p:endswith(headerunit.name) then
-                        includedir = p:sub(1, #p - #headerunit.name - 1)
-                    else
-                        includedir = path.directory(p)
-                    end
-                    if path.is_absolute(includedir) then
-                        includedir = path.relative(includedir, projectdir)
-                    end
-                    table.join2(args, { "-I", includedir, "-x", "c++-user-header", headerunit.name })
-                elseif headerunit.type == ":angle" then
-                    table.join2(args, { "-x", "c++-system-header", headerunit.name })
-                end
-                os.vrunv(compinst:program(), table.join(compinst:compflags({target = target}), args))
-
-            end, {dependfile = target:dependfile(bmifile), files = {headerunit.path}, changed = target:is_rebuilt()})
-        end, {rootjob = opt.rootjob})
-        _add_module_to_mapper(mapper_file, headerunit_path, path.absolute(bmifile, projectdir))
-    end
-end
-
--- generate target user header units for batchcmds
-function generate_user_headerunits_for_batchcmds(target, batchcmds, headerunits, opt)
-    local mapper_file = _get_module_mapper(target)
-
-    -- build headerunits
-    local projectdir = os.projectdir()
-    local depmtime = 0
-    for _, headerunit in ipairs(headerunits) do
-        local flags = {"-c"}
-        local headerunit_path
-        if headerunit.type == ":quote" then
-            local includedir
-            local p = headerunit.path
-            if p:endswith(headerunit.name) then
-                includedir = p:sub(1, #p - #headerunit.name - 1)
-            else
-                includedir = path.directory(p)
-            end
-            if path.is_absolute(includedir) then
-                includedir = path.relative(includedir, projectdir)
-            end
-            table.join2(flags, {"-I", path(includedir), "-x", "c++-user-header", headerunit.name})
-            headerunit_path = path.join(".", path.relative(headerunit.path, projectdir))
-        elseif headerunit.type == ":angle" then
-            table.join2(flags, {"-x", "c++-system-header", headerunit.name})
-            -- if path is relative then its a subtarget path
-            headerunit_path = path.is_absolute(headerunit.path) and headerunit.path or path.join(".", headerunit.path)
-        end
-        local objectfile = target:objectfile(headerunit_path)
-        local outputdir = common.get_outputdir(target, headerunit.path)
-        batchcmds:mkdir(outputdir)
-
-        local bmifilename = path.basename(objectfile) .. get_bmi_extension()
-        local bmifile = (outputdir and path.join(outputdir, bmifilename) or bmifilename)
-        batchcmds:mkdir(path.directory(objectfile))
-
-        batchcmds:show_progress(opt.progress, "${color.build.object}compiling.headerunit.$(mode) %s", headerunit.name)
-        _batchcmds_compile(batchcmds, target, flags)
-        batchcmds:add_depfiles(headerunit.path)
-
-        _add_module_to_mapper(mapper_file, headerunit_path, path.absolute(bmifile, projectdir))
-        depmtime = math.max(depmtime, os.mtime(bmifile))
-    end
-    batchcmds:set_depmtime(depmtime)
-end
-
--- build module files for batchjobs
-function build_modules_for_batchjobs(target, batchjobs, objectfiles, modules, opt)
-    local mapper_file = _get_module_mapper(target)
-
-    -- build modules
-    local projectdir = os.projectdir()
-    local modulesjobs = {}
-    for _, objectfile in ipairs(objectfiles) do
-        local module = modules[objectfile]
-        if module then
-            local cppfile = module.cppfile
-            local name, provide
-            if module.provides then
-                -- assume there that provides is only one, until we encounter the case
-                local length = 0
-                for k, v in pairs(module.provides) do
-                    length = length + 1
-                    name = k
-                    provide = v
-                    cppfile = provide.sourcefile
-                    if length > 1 then
-                        raise("multiple provides are not supported now!")
-                    end
-                    break
-                end
-            end
-            local moduleinfo = table.copy(provide) or {}
-            local dependfile = (provide and provide.bmi) and target:dependfile(provide.bmi) or target:dependfile(objectfile)
-
-            if provide then
-                local fileconfig = target:fileconfig(cppfile)
-                if fileconfig and fileconfig.install then
-                    batchjobs:addjob(name .. "_metafile", function(index, total)
-                        local metafilepath = common.get_metafile(target, cppfile)
-                        depend.on_changed(function()
-                            progress.show((index * 100) / total, "${color.build.object}generating.module.metadata %s", name)
-                            local metadata = common.generate_meta_module_info(target, name, cppfile, module.requires)
-                            json.savefile(metafilepath, metadata)
-                        end, {dependfile = target:dependfile(metafilepath), files = {cppfile}, changed = target:is_rebuilt()})
-                    end, {rootjob = opt.rootjob})
-                end
-            end
-
-            table.join2(moduleinfo, {
-                name = name or cppfile,
-                deps = table.keys(module.requires or {}),
-                sourcefile = cppfile,
-                job = batchjobs:newjob(name or cppfile, function(index, total)
-                    -- append dependencies module now to ensures deps modulemap is filled
-                    for required, _ in pairs(module.requires) do
-                        local m
-                        for _, dep in ipairs(target:orderdeps()) do
-                            m = _get_module_from_mapper(_get_module_mapper(dep), required)
-                            if m then
-                                break
-                            end
-                        end
-                        if m then
-                            _add_module_to_mapper(mapper_file, m[1], m[2])
-                            break
-                        end
-                    end
-
-                    if provide or common.has_module_extension(cppfile) then
-                        if not common.memcache():get2(name or cppfile, "compiling") then
-                            if name and module.external then
-                                common.memcache():set2(name or cppfile, "compiling", true)
-                            end
-                            _build_modulefile(target, cppfile, {
-                                objectfile = objectfile,
-                                dependfile = dependfile,
-                                name = name or cppfile,
-                                progress = (index * 100) / total})
-                        end
-                        target:add("objectfiles", objectfile)
-                    end
-                end)})
-            if provide then
-                _add_module_to_mapper(mapper_file, name, path.absolute(provide.bmi, projectdir))
-            end
-            modulesjobs[name or cppfile] = moduleinfo
-        end
-    end
-
-    -- build batchjobs for modules
-    common.build_batchjobs_for_modules(modulesjobs, batchjobs, opt.rootjob)
-end
-
--- build module files for batchcmds
-function build_modules_for_batchcmds(target, batchcmds, objectfiles, modules, opt)
-    local modulemapperflag = get_modulemapperflag(target)
-    local mapper_file = _get_module_mapper(target)
-
-    -- build modules
-    local projectdir = os.projectdir()
-    local depmtime = 0
-    for _, objectfile in ipairs(objectfiles) do
-        local module = modules[objectfile]
-        if module then
-            local cppfile = module.cppfile
-            local name, provide
-            if module.provides then
-                local length = 0
-                for k, v in pairs(module.provides) do
-                    length = length + 1
-                    name = k
-                    provide = v
-                    cppfile = provide.sourcefile
-                    if length > 1 then
-                        raise("multiple provides are not supported now!")
-                    end
-                    break
-                end
-            end
-            -- append dependencies module now to ensures deps modulemap is filled
-            for required, _ in pairs(module.requires) do
-                local m
-                for _, dep in ipairs(target:orderdeps()) do
-                    m = _get_module_from_mapper(_get_module_mapper(dep), required)
-                    if m then
-                        break
-                    end
-                end
-                if m then
-                    _add_module_to_mapper(mapper_file, m[1], m[2])
-                    break
-                end
-            end
-            if provide or common.has_module_extension(cppfile) then
-                local flags = {"-x", "c++", "-c", path(cppfile), "-o", path(objectfile)}
-                batchcmds:show_progress(opt.progress, "${color.build.object}compiling.module.$(mode) %s", name or cppfile)
-                batchcmds:mkdir(path.directory(objectfile))
-                _batchcmds_compile(batchcmds, target, flags, cppfile)
-                batchcmds:add_depfiles(cppfile)
-                target:add("objectfiles", objectfile)
-                _add_module_to_mapper(mapper_file, name, path.absolute(provide.bmi, projectdir))
-            end
-            depmtime = math.max(depmtime, os.mtime(provide and provide.bmi or objectfile))
-        end
-    end
-    batchcmds:set_depmtime(depmtime)
-end
-
--- not supported atm
-function get_stdmodules(target)
-    local modules = {}
-    return modules
-end
-
-function get_bmi_extension()
-    return ".gcm"
-end
-
-function get_modulesflag(target)
-    local modulesflag = _g.modulesflag
-    if modulesflag == nil then
-        local compinst = target:compiler("cxx")
-        if compinst:has_flags("-fmodules-ts", "cxxflags", {flagskey = "gcc_modules_ts"}) then
-            modulesflag = "-fmodules-ts"
-        end
-        assert(modulesflag, "compiler(gcc): does not support c++ module!")
-        _g.modulesflag = modulesflag or false
-    end
-    return modulesflag or nil
-end
-
-function get_modulemapperflag(target)
-    local modulemapperflag = _g.modulemapperflag
-    if modulemapperflag == nil then
-        local compinst = target:compiler("cxx")
-        if compinst:has_flags("-fmodule-mapper=" .. os.tmpfile(), "cxxflags", {flagskey = "gcc_module_mapper"}) then
-            modulemapperflag = "-fmodule-mapper="
-        end
-        assert(modulemapperflag, "compiler(gcc): does not support c++ module!")
-        _g.modulemapperflag = modulemapperflag or false
-    end
-    return modulemapperflag or nil
-end
-
-function get_depflag(target, format)
-    local depflag = _g.depflag
-    if depflag == nil then
-        local compinst = target:compiler("cxx")
-        if compinst:has_flags("-fdep-format=" .. format, "cxxflags", {flagskey = "gcc_dep_format"}) then
-            depflag = "-fdep-format=" .. format
-        end
-        _g.depflag = depflag or false
-    end
-    return depflag or nil
-end
-
-function get_depfileflag(target)
-    local depfileflag = _g.depfileflag
-    if depfileflag == nil then
-        local compinst = target:compiler("cxx")
-        if compinst:has_flags("-fdep-file=" .. os.tmpfile(), "cxxflags", {flagskey = "gcc_dep_file",
-         on_check = function (ok, errors)
-             if errors:find("cc1plus: error: to generate dependencies") then
-                ok = true
-             end
-             return ok, errors
-        end}) then
-            depfileflag = "-fdep-file="
-        end
-        _g.depfileflag = depfileflag or false
-    end
-    return depfileflag or nil
-end
-
-function get_depoutputflag(target)
-    local depoutputflag = _g.depoutputflag
-    if depoutputflag == nil then
-        local compinst = target:compiler("cxx")
-        if compinst:has_flags("-fdep-output=" .. os.tmpfile() .. ".o", "cxxflags", {flagskey = "gcc_dep_output",
-         on_check = function (ok, errors)
-             if errors:find("cc1plus: error: to generate dependencies") then
-                ok = true
-             end
-             return ok, errors
-        end}) then
-            depoutputflag = "-fdep-output="
-        end
-        _g.depoutputflag = depoutputflag or false
-    end
-    return depoutputflag or nil
-end
-
-function get_cppversionflag(target)
-    local cppversionflag = _g.cppversionflag
-    if cppversionflag == nil then
-        local compinst = target:compiler("cxx")
-        local flags = compinst:compflags({target = target})
-        cppversionflag = table.find_if(flags, function(v) string.startswith(v, "-std=c++") end) or "-std=c++20"
-        _g.cppversionflag = cppversionflag
-    end
-    return cppversionflag or nil
-end