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Diffstat (limited to 'gcc/doc/invoke.texi')
| -rw-r--r-- | gcc/doc/invoke.texi | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 34b597a0925..ebf340793ce 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -491,7 +491,7 @@ in the following sections. -mrnames -msoft-float @gol -m4650 -msingle-float -mmad @gol -mstats -EL -EB -G @var{num} -nocpp @gol --mabi=32 -mabi=n32 -mabi=64 -mabi=eabi @gol +-mabi=32 -mabi=n32 -mabi=64 -mabi=eabi -mabi-fake-default @gol -mfix7000 -mno-crt0 -mflush-func=@var{func} -mno-flush-func @gol -mbranch-likely -mno-branch-likely} @@ -7465,6 +7465,37 @@ selects the one defined by MIPS@. Both these ABIs have 64-bit code when you select a 64-bit architecture, but you can use @option{-mgp32} to get 32-bit code instead. +@item -mabi-fake-default +@opindex mabi-fake-default +You don't want to know what this option does. No, really. I mean +it. Move on to the next option. + +What? You're still here? Oh, well@enddots{} Ok, here's the deal. GCC +wants the default set of options to get the root of the multilib tree, +and the shared library SONAMEs without any multilib-indicating +suffixes. This is not convenience for @samp{mips64-linux-gnu}, since +we want to default to the N32 ABI, while still being binary-compatible +with @samp{mips-linux-gnu} if you stick to the O32 ABI@. Being +binary-compatible means shared libraries should have the same SONAMEs, +and libraries should live in the same location. Having O32 libraries +in a sub-directory named say @file{o32} is not acceptable. + +So we trick GCC into believing that O32 is the default ABI, except +that we override the default with some internal command-line +processing magic. Problem is, if we stopped at that, and you then +created a multilib-aware package that used the output of @command{gcc +-print-multi-lib} to decide which multilibs to build, and how, and +you'd find yourself in an awkward situation when you found out that +some of the options listed ended up mapping to the same multilib, and +none of your libraries was actually built for the multilib that +@option{-print-multi-lib} claims to be the default. So we added this +option that disables the default switcher, falling back to GCC's +original notion of the default library. Confused yet? + +For short: don't ever use this option, unless you find it in the list +of additional options to be used when building for multilibs, in the +output of @option{gcc -print-multi-lib}. + @item -mmips-as @opindex mmips-as Generate code for the MIPS assembler, and invoke @file{mips-tfile} to |