diff mbox series

IBM zSystems: Fix TARGET_D_CPU_VERSIONS

Message ID 20230113175428.1771219-1-stefansf@linux.ibm.com
State New
Headers
Series IBM zSystems: Fix TARGET_D_CPU_VERSIONS |

Commit Message

Stefan Schulze Frielinghaus Jan. 13, 2023, 5:54 p.m. UTC 
  In the context of D the interpretation of S390, S390X, and SystemZ is a
bit fuzzy.  The wording S390X was wrongly deprecated in favour of
SystemZ by commit
https://github.com/dlang/dlang.org/commit/3b50a4c3faf01c32234d0ef8be5f82915a61c23f
Thus, SystemZ is used for 64-bit targets, now, and S390 for 31-bit
targets.  However, in TARGET_D_CPU_VERSIONS depending on TARGET_ZARCH we
set the CPU version to SystemZ.  This is also the case if compiled for
31-bit targets leading to the following error:

libphobos/libdruntime/core/sys/posix/sys/stat.d:967:13: error: static assert:  '96u == 144u' is false
  967 |             static assert(stat_t.sizeof == 144);
      |             ^

Thus in order to keep this patch simple I went for keeping SystemZ for
64-bit targets and S390, as usual, for 31-bit targets and dropped the
distinction between ESA and z/Architecture.

Bootstrapped and regtested on IBM zSystems.  Ok for mainline?

gcc/ChangeLog:

	* config/s390/s390-d.cc (s390_d_target_versions): Fix detection
	of CPU version.
---
 gcc/config/s390/s390-d.cc | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

Comments

Iain Buclaw Jan. 23, 2023, 1:21 p.m. UTC | #1 
Excerpts from Stefan Schulze Frielinghaus via Gcc-patches's message of Januar 13, 2023 6:54 pm:
> In the context of D the interpretation of S390, S390X, and SystemZ is a
> bit fuzzy.  The wording S390X was wrongly deprecated in favour of
> SystemZ by commit
> https://github.com/dlang/dlang.org/commit/3b50a4c3faf01c32234d0ef8be5f82915a61c23f
> Thus, SystemZ is used for 64-bit targets, now, and S390 for 31-bit
> targets.  However, in TARGET_D_CPU_VERSIONS depending on TARGET_ZARCH we
> set the CPU version to SystemZ.  This is also the case if compiled for
> 31-bit targets leading to the following error:
> 
> libphobos/libdruntime/core/sys/posix/sys/stat.d:967:13: error: static assert:  '96u == 144u' is false
>   967 |             static assert(stat_t.sizeof == 144);
>       |             ^
> 

So that I follow, there are three possible combinations?

ESA 31-bit (S390)
ESA 64-bit (what was S390X)
z/Arch 64-bit (SystemZ)

> Thus in order to keep this patch simple I went for keeping SystemZ for
> 64-bit targets and S390, as usual, for 31-bit targets and dropped the
> distinction between ESA and z/Architecture.
> 
> Bootstrapped and regtested on IBM zSystems.  Ok for mainline?
> 

OK by me.  Maybe keep both S390X and SystemZ for TARGET_64BIT? There's
only ever been a binary distinction as far as I'm aware.

Iain.
Stefan Schulze Frielinghaus Jan. 23, 2023, 6:45 p.m. UTC | #2 
On Mon, Jan 23, 2023 at 02:21:46PM +0100, Iain Buclaw wrote:
> Excerpts from Stefan Schulze Frielinghaus via Gcc-patches's message of Januar 13, 2023 6:54 pm:
> > In the context of D the interpretation of S390, S390X, and SystemZ is a
> > bit fuzzy.  The wording S390X was wrongly deprecated in favour of
> > SystemZ by commit
> > https://github.com/dlang/dlang.org/commit/3b50a4c3faf01c32234d0ef8be5f82915a61c23f
> > Thus, SystemZ is used for 64-bit targets, now, and S390 for 31-bit
> > targets.  However, in TARGET_D_CPU_VERSIONS depending on TARGET_ZARCH we
> > set the CPU version to SystemZ.  This is also the case if compiled for
> > 31-bit targets leading to the following error:
> > 
> > libphobos/libdruntime/core/sys/posix/sys/stat.d:967:13: error: static assert:  '96u == 144u' is false
> >   967 |             static assert(stat_t.sizeof == 144);
> >       |             ^
> > 
> 
> So that I follow, there are three possible combinations?
> 
> ESA 31-bit (S390)
> ESA 64-bit (what was S390X)
> z/Arch 64-bit (SystemZ)

There are three combinations:

- s390:  32-bit ABI and ESA mode
- s390:  32-bit ABI and z/Architecture mode
- s390x: 64-bit ABI and z/Architecture mode

Note, depending on the CPU mode z/Architecture is supported by the
32- and 64-bit ABI whereas ESA is only supported by the 32-bit ABI.

Thus, s390 always refers to the 32-bit ABI but does not fix the
instructions set architecture (ESA or z/Architecture).  Whereas s390x
refers to the 64-bit ABI for which only z/Architecture exists.

While nitpicking, typically the target is written in lower case letters,
i.e., not S390X but s390x and likewise s390 instead of S390.

Hope this clarifies the set of possible combinations.  Let me know if
anything else is unclear.

> 
> > Thus in order to keep this patch simple I went for keeping SystemZ for
> > 64-bit targets and S390, as usual, for 31-bit targets and dropped the
> > distinction between ESA and z/Architecture.
> > 
> > Bootstrapped and regtested on IBM zSystems.  Ok for mainline?
> > 
> 
> OK by me.  Maybe keep both S390X and SystemZ for TARGET_64BIT? There's
> only ever been a binary distinction as far as I'm aware.

Sounds good to me.  I will come up with an updated patch.

Cheers,
Stefan
diff mbox series

Patch

diff --git a/gcc/config/s390/s390-d.cc b/gcc/config/s390/s390-d.cc
index d10b45f7de4..ced7f49a988 100644
--- a/gcc/config/s390/s390-d.cc
+++ b/gcc/config/s390/s390-d.cc
@@ -30,10 +30,8 @@  along with GCC; see the file COPYING3.  If not see
 void
 s390_d_target_versions (void)
 {
-  if (TARGET_ZARCH)
+  if (TARGET_64BIT)
     d_add_builtin_version ("SystemZ");
-  else if (TARGET_64BIT)
-    d_add_builtin_version ("S390X");
   else
     d_add_builtin_version ("S390");