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| author | Alexandre Oliva <oliva@adacore.com> | 2022-11-05 03:14:33 -0300 |
|---|---|---|
| committer | Alexandre Oliva <oliva@gnu.org> | 2022-11-05 03:14:33 -0300 |
| commit | 6b1a2474f9e422ef746f7ea13014b288850bb68a (patch) | |
| tree | 391e95f35df7bf1efbefe820003324821508f1c4 /gcc/doc | |
| parent | 95ba31bc4f88a0a2ff9f0ed41f3478cafcb9e040 (diff) | |
| download | gcc-6b1a2474f9e422ef746f7ea13014b288850bb68a.zip gcc-6b1a2474f9e422ef746f7ea13014b288850bb68a.tar.gz gcc-6b1a2474f9e422ef746f7ea13014b288850bb68a.tar.bz2 | |
Support multilib-aware target lib flags self-specs overriding
This patch introduces -fmultiflags, short for multilib TFLAGS, as an
option that does nothing by default, but that can be added to TFLAGS
and mapped to useful options by driver self-specs.
for gcc/ChangeLog
* common.opt (fmultiflags): New.
* doc/invoke.texi: Document it.
* gcc.cc (driver_self_specs): Discard it.
* opts.cc (common_handle_option): Ignore it in the driver.
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/invoke.texi | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index e9207a3..5077cd7 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -738,7 +738,7 @@ Objective-C and Objective-C++ Dialects}. -flto-report -flto-report-wpa -fmem-report-wpa @gol -fmem-report -fpre-ipa-mem-report -fpost-ipa-mem-report @gol -fopt-info -fopt-info-@var{options}@r{[}=@var{file}@r{]} @gol --fprofile-report @gol +-fmultiflags -fprofile-report @gol -frandom-seed=@var{string} -fsched-verbose=@var{n} @gol -fsel-sched-verbose -fsel-sched-dump-cfg -fsel-sched-pipelining-verbose @gol -fstats -fstack-usage -ftime-report -ftime-report-details @gol @@ -19344,6 +19344,34 @@ allocation for the WPA phase only. Makes the compiler print some statistics about permanent memory allocation before or after interprocedural optimization. +@item -fmultiflags +@opindex fmultiflags +This option enables multilib-aware @code{TFLAGS} to be used to build +target libraries with options different from those the compiler is +configured to use by default, through the use of specs (@xref{Spec +Files}) set up by compiler internals, by the target, or by builders at +configure time. + +Like @code{TFLAGS}, this allows the target libraries to be built for +portable baseline environments, while the compiler defaults to more +demanding ones. That's useful because users can easily override the +defaults the compiler is configured to use to build their own programs, +if the defaults are not ideal for their target environment, whereas +rebuilding the runtime libraries is usually not as easy or desirable. + +Unlike @code{TFLAGS}, the use of specs enables different flags to be +selected for different multilibs. The way to accomplish that is to +build with @samp{make TFLAGS=-fmultiflags}, after configuring +@samp{--with-specs=%@{fmultiflags:...@}}. + +This option is discarded by the driver once it's done processing driver +self spec. + +It is also useful to check that @code{TFLAGS} are being used to build +all target libraries, by configuring a non-bootstrap compiler +@samp{--with-specs='%@{!fmultiflags:%emissing TFLAGS@}'} and building +the compiler and target libraries. + @item -fprofile-report @opindex fprofile-report Makes the compiler print some statistics about consistency of the |