diff options
| author | palmer <palmer@138bc75d-0d04-0410-961f-82ee72b054a4> | 2017-10-27 15:22:43 +0000 |
|---|---|---|
| committer | palmer <palmer@138bc75d-0d04-0410-961f-82ee72b054a4> | 2017-10-27 15:22:43 +0000 |
| commit | 6b073ae6730df586f8ee349d83b8ed0c96be63f8 (patch) | |
| tree | 974113926eccd512fe676cd667fb43e905e99250 | |
| parent | 41057e20e300b5965f5855f4a8b0136a89253b5f (diff) | |
| download | gcc-6b073ae6730df586f8ee349d83b8ed0c96be63f8.tar.gz | |
RISC-V: Correct and improve the "-mabi" documentation
The documentation for the "-mabi" argument on RISC-V was incorrect. We
chose to treat this as a documentation bug rather than a code bug, and
to make the documentation match what GCC currently does. In the
process, I also improved the documentation a bit.
Thanks to Alex Bradbury for finding the bug!
PR target/82717: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82717
gcc/ChangeLog
2017-10-27 Palmer Dabbelt <palmer@dabbelt.com>
PR target/82717
* doc/invoke.texi (RISC-V) <-mabi>: Correct and improve.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@254153 138bc75d-0d04-0410-961f-82ee72b054a4
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 23 |
2 files changed, 25 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index bf87fafca14..68d5943e90b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2017-10-27 Palmer Dabbelt <palmer@dabbelt.com> + + PR target/82717 + * doc/invoke.texi (RISC-V) <-mabi>: Correct and improve. + 2017-10-27 Jan Hubicka <hubicka@ucw.cz> * config/i386/x86-tune.def (X86_TUNE_PARTIAL_REG_DEPENDENCY, diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 91b05402ecc..0474cee0487 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -21705,9 +21705,26 @@ When generating PIC code, allow the use of PLTs. Ignored for non-PIC. @item -mabi=@var{ABI-string} @opindex mabi -Specify integer and floating-point calling convention. This defaults to the -natural calling convention: e.g.@ LP64 for RV64I, ILP32 for RV32I, LP64D for -RV64G. +@item -mabi=@var{ABI-string} +@opindex mabi +Specify integer and floating-point calling convention. @var{ABI-string} +contains two parts: the size of integer types and the registers used for +floating-point types. For example @samp{-march=rv64ifd -mabi=lp64d} means that +@samp{long} and pointers are 64-bit (implicitly defining @samp{int} to be +32-bit), and that floating-point values up to 64 bits wide are passed in F +registers. Contrast this with @samp{-march=rv64ifd -mabi=lp64f}, which still +allows the compiler to generate code that uses the F and D extensions but only +allows floating-point values up to 32 bits long to be passed in registers; or +@samp{-march=rv64ifd -mabi=lp64}, in which no floating-point arguments will be +passed in registers. + +The default for this argument is system dependent, users who want a specific +calling convention should specify one explicitly. The valid calling +conventions are: @samp{ilp32}, @samp{ilp32f}, @samp{ilp32d}, @samp{lp64}, +@samp{lp64f}, and @samp{lp64d}. Some calling conventions are impossible to +implement on some ISAs: for example, @samp{-march=rv32if -mabi=ilp32d} is +invalid because the ABI requires 64-bit values be passed in F registers, but F +registers are only 32 bits wide. @item -mfdiv @itemx -mno-fdiv |