Re: [PATCH v2 2/2] bpf: add v3 atomic instructions

2023-07-26 Thread Jose E. Marchesi via Gcc-patches 


OK.
Thanks!

> [Changes from v1: fix merge issue in invoke.texi]
>
> This patch adds support for the general atomic operations introduced in
> eBPF v3. In addition to the existing atomic add instruction, this adds:
>  - Atomic and, or, xor
>  - Fetching versions of these operations (including add)
>  - Atomic exchange
>  - Atomic compare-and-exchange
>
> To control emission of these instructions, a new target option
> -m[no-]v3-atomics is added. This option is enabled by -mcpu=v3
> and above.
>
> Support for these instructions was recently added in binutils.
>
> gcc/
>
>   * config/bpf/bpf.opt (mv3-atomics): New option.
>   * config/bpf/bpf.cc (bpf_option_override): Handle it here.
>   * config/bpf/bpf.h (enum_reg_class): Add R0 class.
>   (REG_CLASS_NAMES): Likewise.
>   (REG_CLASS_CONTENTS): Likewise.
>   (REGNO_REG_CLASS): Handle R0.
>   * config/bpf/bpf.md (UNSPEC_XADD): Rename to UNSPEC_AADD.
>   (UNSPEC_AAND): New unspec.
>   (UNSPEC_AOR): Likewise.
>   (UNSPEC_AXOR): Likewise.
>   (UNSPEC_AFADD): Likewise.
>   (UNSPEC_AFAND): Likewise.
>   (UNSPEC_AFOR): Likewise.
>   (UNSPEC_AFXOR): Likewise.
>   (UNSPEC_AXCHG): Likewise.
>   (UNSPEC_ACMPX): Likewise.
>   (atomic_add): Use UNSPEC_AADD and atomic type attribute.
>   Move to...
>   * config/bpf/atomic.md: ...Here. New file.
>   * config/bpf/constraints.md (t): New constraint for R0.
>   * doc/invoke.texi (eBPF Options): Document -mv3-atomics.
>
> gcc/testsuite/
>
>   * gcc.target/bpf/atomic-cmpxchg-1.c: New test.
>   * gcc.target/bpf/atomic-cmpxchg-2.c: New test.
>   * gcc.target/bpf/atomic-fetch-op-1.c: New test.
>   * gcc.target/bpf/atomic-fetch-op-2.c: New test.
>   * gcc.target/bpf/atomic-fetch-op-3.c: New test.
>   * gcc.target/bpf/atomic-op-1.c: New test.
>   * gcc.target/bpf/atomic-op-2.c: New test.
>   * gcc.target/bpf/atomic-op-3.c: New test.
>   * gcc.target/bpf/atomic-xchg-1.c: New test.
>   * gcc.target/bpf/atomic-xchg-2.c: New test.
> ---
>  gcc/config/bpf/atomic.md  | 185 ++
>  gcc/config/bpf/bpf.cc |   3 +
>  gcc/config/bpf/bpf.h  |   6 +-
>  gcc/config/bpf/bpf.md |  29 ++-
>  gcc/config/bpf/bpf.opt|   4 +
>  gcc/config/bpf/constraints.md |   3 +
>  gcc/doc/invoke.texi   |   8 +-
>  .../gcc.target/bpf/atomic-cmpxchg-1.c |  19 ++
>  .../gcc.target/bpf/atomic-cmpxchg-2.c |  19 ++
>  .../gcc.target/bpf/atomic-fetch-op-1.c|  50 +
>  .../gcc.target/bpf/atomic-fetch-op-2.c|  50 +
>  .../gcc.target/bpf/atomic-fetch-op-3.c|  49 +
>  gcc/testsuite/gcc.target/bpf/atomic-op-1.c|  49 +
>  gcc/testsuite/gcc.target/bpf/atomic-op-2.c|  49 +
>  gcc/testsuite/gcc.target/bpf/atomic-op-3.c|  49 +
>  gcc/testsuite/gcc.target/bpf/atomic-xchg-1.c  |  20 ++
>  gcc/testsuite/gcc.target/bpf/atomic-xchg-2.c  |  20 ++
>  17 files changed, 593 insertions(+), 19 deletions(-)
>  create mode 100644 gcc/config/bpf/atomic.md
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-cmpxchg-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-cmpxchg-2.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-fetch-op-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-fetch-op-2.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-fetch-op-3.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-op-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-op-2.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-op-3.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-xchg-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-xchg-2.c
>
> diff --git a/gcc/config/bpf/atomic.md b/gcc/config/bpf/atomic.md
> new file mode 100644
> index 000..caf8cc15cd4
> --- /dev/null
> +++ b/gcc/config/bpf/atomic.md
> @@ -0,0 +1,185 @@
> +;; Machine description for eBPF.
> +;; Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +;; This file is part of GCC.
> +
> +;; GCC is free software; you can redistribute it and/or modify
> +;; it under the terms of the GNU General Public License as published by
> +;; the Free Software Foundation; either version 3, or (at your option)
> +;; any later version.
> +
> +;; GCC is distributed in the hope that it will be useful,
> +;; but WITHOUT ANY WARRANTY; without even the implied warranty of
> +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +;; GNU General Public License for more details.
> +
> +;; You should have received a copy of the GNU General Public License
> +;; along with GCC; see the file COPYING3.  If not see
> +;; .
> +
> +
> +(define_mode_iterator AMO [SI DI])
> +
> +;;; Plain atomic modify operations.
> +
> +;; Non-fetching atomic add predates all

[PATCH v2 2/2] bpf: add v3 atomic instructions

2023-07-25 Thread David Faust via Gcc-patches 
[Changes from v1: fix merge issue in invoke.texi]

This patch adds support for the general atomic operations introduced in
eBPF v3. In addition to the existing atomic add instruction, this adds:
 - Atomic and, or, xor
 - Fetching versions of these operations (including add)
 - Atomic exchange
 - Atomic compare-and-exchange

To control emission of these instructions, a new target option
-m[no-]v3-atomics is added. This option is enabled by -mcpu=v3
and above.

Support for these instructions was recently added in binutils.

gcc/

* config/bpf/bpf.opt (mv3-atomics): New option.
* config/bpf/bpf.cc (bpf_option_override): Handle it here.
* config/bpf/bpf.h (enum_reg_class): Add R0 class.
(REG_CLASS_NAMES): Likewise.
(REG_CLASS_CONTENTS): Likewise.
(REGNO_REG_CLASS): Handle R0.
* config/bpf/bpf.md (UNSPEC_XADD): Rename to UNSPEC_AADD.
(UNSPEC_AAND): New unspec.
(UNSPEC_AOR): Likewise.
(UNSPEC_AXOR): Likewise.
(UNSPEC_AFADD): Likewise.
(UNSPEC_AFAND): Likewise.
(UNSPEC_AFOR): Likewise.
(UNSPEC_AFXOR): Likewise.
(UNSPEC_AXCHG): Likewise.
(UNSPEC_ACMPX): Likewise.
(atomic_add): Use UNSPEC_AADD and atomic type attribute.
Move to...
* config/bpf/atomic.md: ...Here. New file.
* config/bpf/constraints.md (t): New constraint for R0.
* doc/invoke.texi (eBPF Options): Document -mv3-atomics.

gcc/testsuite/

* gcc.target/bpf/atomic-cmpxchg-1.c: New test.
* gcc.target/bpf/atomic-cmpxchg-2.c: New test.
* gcc.target/bpf/atomic-fetch-op-1.c: New test.
* gcc.target/bpf/atomic-fetch-op-2.c: New test.
* gcc.target/bpf/atomic-fetch-op-3.c: New test.
* gcc.target/bpf/atomic-op-1.c: New test.
* gcc.target/bpf/atomic-op-2.c: New test.
* gcc.target/bpf/atomic-op-3.c: New test.
* gcc.target/bpf/atomic-xchg-1.c: New test.
* gcc.target/bpf/atomic-xchg-2.c: New test.
---
 gcc/config/bpf/atomic.md  | 185 ++
 gcc/config/bpf/bpf.cc |   3 +
 gcc/config/bpf/bpf.h  |   6 +-
 gcc/config/bpf/bpf.md |  29 ++-
 gcc/config/bpf/bpf.opt|   4 +
 gcc/config/bpf/constraints.md |   3 +
 gcc/doc/invoke.texi   |   8 +-
 .../gcc.target/bpf/atomic-cmpxchg-1.c |  19 ++
 .../gcc.target/bpf/atomic-cmpxchg-2.c |  19 ++
 .../gcc.target/bpf/atomic-fetch-op-1.c|  50 +
 .../gcc.target/bpf/atomic-fetch-op-2.c|  50 +
 .../gcc.target/bpf/atomic-fetch-op-3.c|  49 +
 gcc/testsuite/gcc.target/bpf/atomic-op-1.c|  49 +
 gcc/testsuite/gcc.target/bpf/atomic-op-2.c|  49 +
 gcc/testsuite/gcc.target/bpf/atomic-op-3.c|  49 +
 gcc/testsuite/gcc.target/bpf/atomic-xchg-1.c  |  20 ++
 gcc/testsuite/gcc.target/bpf/atomic-xchg-2.c  |  20 ++
 17 files changed, 593 insertions(+), 19 deletions(-)
 create mode 100644 gcc/config/bpf/atomic.md
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-cmpxchg-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-cmpxchg-2.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-fetch-op-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-fetch-op-2.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-fetch-op-3.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-op-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-op-2.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-op-3.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-xchg-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/atomic-xchg-2.c

diff --git a/gcc/config/bpf/atomic.md b/gcc/config/bpf/atomic.md
new file mode 100644
index 000..caf8cc15cd4
--- /dev/null
+++ b/gcc/config/bpf/atomic.md
@@ -0,0 +1,185 @@
+;; Machine description for eBPF.
+;; Copyright (C) 2023 Free Software Foundation, Inc.
+
+;; This file is part of GCC.
+
+;; GCC is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+
+;; GCC is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GCC; see the file COPYING3.  If not see
+;; .
+
+
+(define_mode_iterator AMO [SI DI])
+
+;;; Plain atomic modify operations.
+
+;; Non-fetching atomic add predates all other BPF atomic insns.
+;; Use xadd{w,dw} for compatibility with older GAS without support
+;; for v3 atomics.  Newer GAS supports "aadd[32]" in line with the
+;; other