On Thu, Nov 29, 2012 at 12:43 AM, Richard Biener <richard.guent...@gmail.com> wrote: > On Thu, Nov 29, 2012 at 5:18 AM, H.J. Lu <hjl.to...@gmail.com> wrote: >> From: "H.J. Lu" <hjl.to...@gmail.com> >> To: gcc-patches@gcc.gnu.org >> Cc: Joseph Myers <jos...@codesourcery.com>, Paolo Bonzini <bonz...@gnu.org> >> Bcc: >> Subject: [PATCH] Support -fuse-ld=bfd and -fuse-ld=gold >> Reply-To: >> >> Hi, >> >> Binutils supports 2 linkers, ld.gold and ld.bfd. One of them is >> configured as the default linker, ld, which is used by GCC. Sometimes, >> we want to use the alternate linker with GCC at run-time. This patch >> adds -fuse-ld=bfd and -fuse-ld=gold options to GCC driver. It changes >> collect2.c to pick either ld.bfd or ld.gold. It also adds >> ORIGINAL_LD_BFD_FOR_TARGET and ORIGINAL_LD_GOLD_FOR_TARGET to >> exec-tool.in to add -fuse-ld=bfd and -fuse-ld=gold support to >> collect-ld. Since ld.bfd nor ld.gold know the new options, you >> will get >> >> # ./xgcc -B./ /tmp/x.c -fuse-ld=gold -v >> ... >> ./collect-ld --eh-frame-hdr -m elf_x86_64 -dynamic-linker >> /lib64/ld-linux-x86-64.so.2 -fuse-ld=gold /lib/../lib64/crt1.o >> /lib/../lib64/crti.o ./crtbegin.o -L. -L/lib/../lib64 -L/usr/lib/../lib64 >> /tmp/cclVWcGz.o -v -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc >> --as-needed -lgcc_s --no-as-needed ./crtend.o /lib/../lib64/crtn.o >> GNU gold (Linux/GNU Binutils 2.23.51.0.7.20121127) 1.11 >> /usr/local/bin/ld.gold: fatal error: -f/--auxiliary may not be used without >> -shared >> collect2: error: ld returned 1 exit status >> >> This is because we pass everything to ld and ld.bfd/ld.gold doesn't >> understand -fuse-ld=bfd/-fuse-ld=gold. It isn't a problem for collect2 >> since it will filter-out -fuse-ld=bfd/-fuse-ld=gold. I will submit a >> binutils patch to ignore -fuse-ld=bfd/-fuse-ld=gold, similar to -flto >> options. >> >> OK to install? > > Do we need to consider GNU ld and gold coming from different binutils versions > and thus do we need two sets of linker feature tests at configure > time? Eventually > also if GNU ld and gold are not in feature-parity for the same binutils > version? > > That is, isn't this going to create hard to debug issues for users? >
Actually, it helps to debug issues for users. At the moment, we don't know which linker is the default linker. With -fuse-ld, we can specify which linker to use. -- H.J.
