[PATCH][middle-end][i386][Version 4] Add -fzero-call-used-regs=[skip|used-gpr-arg|used-arg|all-arg|used-gpr|all-gpr|used|all]

[Qing Zhao]

Hi, Richard, 

I changed the “enum” to “namespace”.

There is no issue for C++ compilation. However, flag-types.h header file is also included by C modules and compiled with gcc, then I got a lot of following compilation errors:

make[4]: Entering directory '/home/qinzhao/Work/x86-build/x86_64-pc-linux-gnu/libgcc'
In file included from ../.././gcc/options.h:6,
                 from ../.././gcc/tm.h:22,
                 from ../../../x86-gcc/libgcc/libgcc2.c:29,
                 from ../../../x86-gcc/libgcc/config/i386/64/_multc3.c:6:
../../../x86-gcc/libgcc/../gcc/flag-types.h:289:1: error: unknown type name ‘namespace’
  289 | namespace  zero_regs_code {
      | ^~~~~~~~~

Looks like that I should not put this new namespace inside “flag-types.h”?  Which other header file I should put this namespace in? 

thanks.

Qing

> On Oct 28, 2020, at 9:24 AM, Qing Zhao via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> 
> Okay, I will change it to namespace.
> 
> Qing
> 
>> On Oct 28, 2020, at 9:19 AM, Richard Sandiford <richard.sandiford@arm.com> wrote:
>> 
>> Qing Zhao <QING.ZHAO@ORACLE.COM <mailto:QING.ZHAO@ORACLE.COM>> writes:
>>> Hi, Richard,
>>> 
>>> In order to be consistent with other flags in flag-types.h, for example, “sanitize_code”,
>>> I didn’t use namespace, instead making the name more specific as following:
>>> 
>>> /* Different settings for zeroing subset of registers.  */
>>> enum  zero_regs_flags {
>>> ZERO_REGS_UNSET = 0,
>>> ZERO_REGS_SKIP = 1UL << 0,
>>> ZERO_REGS_ONLY_USED = 1UL << 1,
>>> ZERO_REGS_ONLY_GPR = 1UL << 2,
>>> ZERO_REGS_ONLY_ARG = 1UL << 3,
>>> ZERO_REGS_ENABLED = 1UL << 4,
>>> ZERO_REGS_USED_GPR_ARG = ZERO_REGS_ENABLED | ZERO_REGS_ONLY_USED
>>>                          | ZERO_REGS_ONLY_GPR | ZERO_REGS_ONLY_ARG,
>>> ZERO_REGS_USED_GPR = ZERO_REGS_ENABLED | ZERO_REGS_ONLY_USED
>>>                      | ZERO_REGS_ONLY_GPR,
>>> ZERO_REGS_USED_ARG = ZERO_REGS_ENABLED | ZERO_REGS_ONLY_USED
>>>                      | ZERO_REGS_ONLY_ARG,
>>> ZERO_REGS_USED = ZERO_REGS_ENABLED | ZERO_REGS_ONLY_USED,
>>> ZERO_REGS_ALL_GPR_ARG = ZERO_REGS_ENABLED | ZERO_REGS_ONLY_GPR
>>>                         | ZERO_REGS_ONLY_ARG,
>>> ZERO_REGS_ALL_GPR = ZERO_REGS_ENABLED | ZERO_REGS_ONLY_GPR,
>>> ZERO_REGS_ALL_ARG = ZERO_REGS_ENABLED | ZERO_REGS_ONLY_ARG,
>>> ZERO_REGS_ALL = ZERO_REGS_ENABLED
>>> };
>>> 
>>> Is this good?
>>> 
>>> Or you still prefer namespace?
>> 
>> I prefer the namespace.  I realise namespaces aren't used that much
>> in GCC yet, but they *are* used.
>> 
>> The advantage they have is that it's possible to do:
>> 
>> using namespace ...;
>> 
>> in contexts where there's no ambiguity.  They also make lines like
>> the | ones above easier to read.
>> 
>> Thanks,
>> Richard
>