如何改变默认的 linker

[iujakchu]

我想使用lld来链接，所以我使用了set_toolchains("clang-13") 和set_toolset("ld","clang++")
但是默认似乎还是用的ld来链接
xmake.lua:

add_rules("mode.debug", "mode.release")

target("cm")
set_toolchains("clang-13")
set_toolset("ld", "clang++")
set_kind("binary")
add_files("src/*.cpp")
-- add_includedirs("back/target/cxxbridge/back/src/")
add_files("back/target/cxxbridge/back/src/*.cc")
add_links("back")
add_linkdirs("back/target/release/")

xmake -vD:

clang++ -o build/linux/x86_64/release/cm build/.objs/cm/linux/x86_64/release/src/main.cpp.o build/.objs/cm/linux/x86_64/release/back/target/cxxbridge/back/src/lib.rs.cc.o -m64 -Lback/target/release -s -lback
error: @programdir/modules/private/async/runjobs.lua:256: @programdir/actions/build/kinds/binary.lua:74: @programdir/core/sandbox/modules/os.lua:257: /usr/bin/ld: back/target/release/libback.a: error adding symbols: file format not recognized
clang-13: error: linker command failed with exit code 1 (use -v to see invocation)

stack traceback:
    [C]: in function 'error'
    [@programdir/core/base/os.lua:872]:
    [@programdir/core/sandbox/modules/os.lua:257]: in function 'runv'
    [@programdir/modules/core/tools/gcc.lua:363]:
    [C]: in function 'xpcall'
    [@programdir/core/base/utils.lua:280]:
    [@programdir/actions/build/kinds/binary.lua:74]: in function 'callback'
    [@programdir/modules/core/project/depend.lua:189]: in function 'on_changed'
    [@programdir/actions/build/kinds/binary.lua:55]: in function '_do_link_target'
    [@programdir/actions/build/kinds/binary.lua:102]:
    [@programdir/actions/build/kinds/binary.lua:129]: in function '_link_target'
    [@programdir/actions/build/kinds/binary.lua:157]: in function 'jobfunc'
    [@programdir/modules/private/async/runjobs.lua:232]:
    [C]: in function 'xpcall'
    [@programdir/core/base/utils.lua:280]: in function 'trycall'
    [@programdir/core/sandbox/modules/try.lua:121]: in function 'try'
    [@programdir/modules/private/async/runjobs.lua:218]: in function 'cotask'
    [@programdir/core/base/scheduler.lua:388]:

stack traceback:
	[C]: in function 'error'
	@programdir/core/base/os.lua:872: in function 'os.raiselevel'
	(...tail calls...)
	@programdir/modules/private/async/runjobs.lua:256: in field 'catch'
	@programdir/core/sandbox/modules/try.lua:127: in global 'try'
	@programdir/modules/private/async/runjobs.lua:218: in upvalue 'cotask'
	@programdir/core/base/scheduler.lua:388: in function <@programdir/core/base/scheduler.lua:385>

是我理解有问题吗？

[waruqi]

你要用 -fuse-ld=lld 让clang 内部自己切 linker ，而不是直接切 clang++ 到 lld，即使你这么切了，你还得自己处理一堆 c++ 等 runtime flags 和硬编码路径，否则链接会各种跪

[iujakchu]

我已经链接好了，请问有没有类似set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)的参数呢？

[waruqi]

目前没，你可以自己 add_cxflags/add_ldflags 设置

[iujakchu]

请问这个得怎么设置呢，我试了-flto，可是似乎并没有作用

[iujakchu]

我写了一个demo,可以链接但是lto/ipo 优化似乎没有开启