On 2012.11.29 at 09:43 +0100, Richard Biener 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?
Additionally, what is the rationale for this patch? IOW why isn't the following enough? x4 ~ # ln -f /usr/x86_64-pc-linux-gnu/binutils-bin/git/ld.gold /usr/x86_64-pc-linux-gnu/binutils-bin/git/ld x4 ~ # ld -v GNU gold (GNU Binutils 2.23.51.20121126) 1.11 x4 ~ # ln -f /usr/x86_64-pc-linux-gnu/binutils-bin/git/ld.bfd /usr/x86_64-pc-linux-gnu/binutils-bin/git/ld x4 ~ # ld -v GNU ld (GNU Binutils) 2.23.51.20121126 Or is this meant as a temporary workaround hack for gold bugs? -- Markus
