[ColdFire 53/63] Static chain fixes

[Richard Sandiford]

Jeffrey Law <law@redhat.com> writes:
> On Wed, 2007-01-10 at 12:10 +0000, Richard Sandiford wrote:
>> m68k*-elf targets use %a0 as both the incoming structure return address
>> _and_ the static chain pointer.  This causes a conflict if a nested function
>> returns a structure.
>> 
>> This patch moves the static chain register to %a1 for these targets only.
>> It also generalises the template code to cope with static chain registers
>> other than %a0.
>> 
>> Richard
>> 
>> 
>> gcc/
>> 200x-xx-xx  Nathan Sidwell  <nathan@codesourcery.com>
>> 	    Richard Sandiford  <richard@codesourcery.com>
>> 
>> 	* config/m68k/m68k.h (M68K_STATIC_CHAIN_REG_NAME): New macro.
>> 	(INITIALIZE_TRAMPOLINE): Use STATIC_CHAIN_REGNUM.
>> 	(__transfer_from_trampoline): Use M68K_STATIC_CHAIN_REG_NAME.
>> 	* config/m68k/m68kelf.h (STATIC_CHAIN_REGNUM): Override.
>> 	(M68K_STATIC_CHAIN_REG_NAME): Likewise.
>> 	* config/m68k/netbsd-elf.h (M68K_STATIC_CHAIN_REG_NAME): Likewise.
>> 
>> gcc/testsuite/
>> 200x-xx-xx  Nathan Sidwell  <nathan@codesourcery.com>
>> 
>> 	* gcc.c-torture/execute/nestfunc-7.c: New.
> Isn't this an ABI change?  If so it needs to be documented at the least
> so that users of the m68k elf port aren't caught by surprise.

Of sorts, although I'm not aware of any actual XFmode emulation
code for ColdFire.  I suspect most ColdFire users just avoided
using long double altogether.  This may be my ignorance though. ;)

To be honest, I wasn't involved in the discussions that led to this
change, but I thought lack of XFmode emulation was the main reason.

> I think we've now got two ABI changes to document for the next release
> of GCC.  If we don't have a good place to document them we should make
> it now.

Good point.  In the past, I've documented MIPS ABI changes in
gcc-x.y/changes.html.  I don't know how well that worked though.

Richard