ld -m --verbose实际上做了什么？

Question

我很困惑这个命令。手册页http://linux.die.net/man/1/ld表示它“模拟仿真链接器，你可以用--verbose或-V选项列出可用的仿真器。”但是，“可用仿真”是什么意思？

例如，我用下面的命令链接对象：

ld -r -nostdlib -L/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib \ 
-m elf_x86_64 --verbose ./arch/x86/x86_64.o ./mini-os_app.o ./blkfront.o ./events.o ./fbfront.o \ 
./gntmap.o ./gnttab.o ./hypervisor.o ./kernel.o ./lock.o ./main.o ./mm.o ./netfront.o ./sched.o \ 
./lib/ctype.o ./lib/math.o ./lib/printf.o ./lib/stack_chk_fail.o ./lib/string.o ./lib/sys.o \ 
./lib/xmalloc.o ./lib/xs.o ./xenbus/xenbus.o ./console/console.o ./console/xencons_ring.o \ 
./console/xenbus.o ./lwip.a -L./arch/x86 -lx86_64 -lc -lglib-2.0 -lvmi -o ./mini-os.o 
GNU ld (GNU Binutils for Ubuntu) 2.22 
    Supported emulations: 
    elf_x86_64 
    elf32_x86_64 
    elf_i386 
    i386linux 
    elf_l1om 
    elf_k1om 
using internal linker script: 
================================================== 
(>>> scripts displayed here, neglected <<<) 
================================================== 
... 
attempt to open /media/wind/lab/xen/xen/xen-4.4.0/stubdom/mini-os-x86_64-vmi/arch/x86/libx86_64.a succeeded 
(>>> lots of *.o listed here for libc.a <<<) 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/mini-os-x86_64-vmi/arch/x86/libx86_64.a)mm.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/mini-os-x86_64-vmi/arch/x86/libx86_64.a)sched.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/mini-os-x86_64-vmi/arch/x86/libx86_64.a)setup.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/mini-os-x86_64-vmi/arch/x86/libx86_64.a)time.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/mini-os-x86_64-vmi/arch/x86/libx86_64.a)traps.o 
... 
attempt to open /media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libglib-2.0.a succeeded 
(>>> why no *.o files listed here? <<<) 
attempt to open /media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a succeeded 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-accessors.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-convenience.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-core.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-events.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-memory.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-read.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-interface.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-kvm.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-memory_cache.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-xen.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)lt1-libvmi_la-core.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)lt2-libvmi_la-memory.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-symbols.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)lt3-libvmi_la-core.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-kpcr.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)lt4-libvmi_la-memory.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-peparse.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-process.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)grammar.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)lexicon.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-cache.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-strmatch.o 
(/media/wind/lab/xen/xen/xen-4.4.0/stubdom/cross-root-x86_64/x86_64-xen-elf/lib/libvmi.a)libvmi_la-file.o 

如上输出表现，似乎每* .A图书馆应该有自己的*的.o上市。但是，如果没有* .o列出某个* .a库（例如上面显示的glib-2.0.a），那么这意味着什么？

预先感谢您！

Answer 1

ld -m选项用于链接.o文件，为使用-m选项作为参数提供的硬件平台创建可执行文件。

E.g.如果您指定了ld -m elf_x86_64 ...，则会创建一个可在x86_64系统上运行的可执行文件（假定没有发生错误）。这通常在交叉编译期间使用。即在您尝试为与正在构建的平台不同的平台创建可执行文件的情况下。