| Message ID | 4D861AF7.2000903@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Sun, 2011-03-20 at 15:19 +0000, Ramana Radhakrishnan wrote: > Hi, > > This fixes up documentation for the -marm option and changes the > behaviour of mthumb to reject the negative options to bring this to > behave similar to the marm option. The option needs to be documented > since we now have situations where toolchains default to Thumb state and > folks need a way of overriding this. I would like a review of this > before committing it since this is a change to the command line options. > > Tested by building a cross toolchain to arm-linux-gnueabi and verified > that -mno-thumb is rejected and looking up the documentation after it > was rebuilt. > > Ok ? > > cheers > Ramana > > > 2011-03-20 Ramana Radhakrishnan <ramana.radhakrishnan@linaro.org> > > PR target/47930 > * config/arm/arm.opt (marm): Document it. > (mthumb): Reject negative variant. +@item -marm +@opindex marm +Generate code for the 32 bit ARM instruction set. This is used to +override and generate code in ARM state if the compiler has been +configured to be built in Thumb state. This option is not passed to the +assembler. I'd suggest @item -mthumb @itemx -marm @opindex marm @opindex mthumb Select between generating code that executes in ARM and Thumb states. The default for most configurations is to generate code that executes in ARM state, but the default can be changed by configuring GCC with the @option{--with-mode=}@var{state} configure option. I don't see any need to talk about the Thumb1/Thumb2 behaviour here any more than we do about other ISA variants in ARM state. Nor do I think it's relevant to talk about this option in relation to the assembler. The arm.opt change is OK, but 'Report' should stay; and it should also be added to the -marm case. R.
Index: gcc/doc/invoke.texi =================================================================== --- gcc/doc/invoke.texi (revision 171192) +++ gcc/doc/invoke.texi (working copy) @@ -10109,6 +10109,13 @@ @option{-mno-apcs-reentrant}. @end ignore +@item -marm +@opindex marm +Generate code for the 32 bit ARM instruction set. This is used to +override and generate code in ARM state if the compiler has been +configured to be built in Thumb state. This option is not passed to the +assembler. + @item -mthumb-interwork @opindex mthumb-interwork Generate code which supports calling between the ARM and Thumb @@ -10354,7 +10361,8 @@ @item -mthumb @opindex mthumb Generate code for the Thumb instruction set. The default is to -use the 32-bit ARM instruction set. +use the 32-bit ARM instruction set unless the compiler defaults to building +with Thumb using the @option{--with-mode=thumb} option. This option automatically enables either 16-bit Thumb-1 or mixed 16/32-bit Thumb-2 instructions based on the @option{-mcpu=@var{name}} and @option{-march=@var{name}} options. This option is not passed to the Index: gcc/config/arm/arm.opt =================================================================== --- gcc/config/arm/arm.opt (revision 171192) +++ gcc/config/arm/arm.opt (working copy) @@ -49,7 +49,8 @@ Specify the name of the target architecture marm -Target RejectNegative InverseMask(THUMB) Undocumented +Target RejectNegative InverseMask(THUMB) +Generate code in 32 bit ARM state. mbig-endian Target Report RejectNegative Mask(BIG_END) @@ -130,7 +131,7 @@ Specify the minimum bit alignment of structures mthumb -Target Report Mask(THUMB) +Target RejectNegative Mask(THUMB) Compile for the Thumb not the ARM mthumb-interwork