Re: [Qemu-devel] [PATCH 2/3] decodetree: Suppress redundant declaration warnings

From: Alistair Francis <alistair23@gmail.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"open list:RISC-V" <qemu-riscv@nongnu.org>,
	"qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>,
	qemu-arm <qemu-arm@nongnu.org>,
	"Alistair Francis" <Alistair.Francis@wdc.com>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 2/3] decodetree: Suppress redundant declaration warnings
Date: Fri, 9 Aug 2019 19:02:44 -0700	[thread overview]
Message-ID: <CAKmqyKNU0UV_-wEqFgQLFqAUXBxHZyiu1dBX4bPachkYKTB=Mw@mail.gmail.com> (raw)
In-Reply-To: <20190809154153.31763-3-richard.henderson@linaro.org>

On Fri, Aug 9, 2019 at 8:42 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> We can tell that a decodetree input file is "secondary" when it
> uses an argument set marked "!extern".  This indicates that at
> least one of the insn translation functions will have already
> been declared by the "primary" input file, but given only the
> secondary we cannot tell which.
>
> Avoid redundant declaration warnings by suppressing them with pragmas.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  scripts/decodetree.py | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/scripts/decodetree.py b/scripts/decodetree.py
> index a2490aeb74..f02c8acca1 100755
> --- a/scripts/decodetree.py
> +++ b/scripts/decodetree.py
> @@ -33,6 +33,7 @@ arguments = {}
>  formats = {}
>  patterns = []
>  allpatterns = []
> +anyextern = False
>
>  translate_prefix = 'trans'
>  translate_scope = 'static '
> @@ -485,12 +486,14 @@ def parse_arguments(lineno, name, toks):
>      """Parse one argument set from TOKS at LINENO"""
>      global arguments
>      global re_ident
> +    global anyextern
>
>      flds = []
>      extern = False
>      for t in toks:
>          if re_fullmatch('!extern', t):
>              extern = True
> +            anyextern = True
>              continue
>          if not re_fullmatch(re_ident, t):
>              error(lineno, 'invalid argument set token "{0}"'.format(t))
> @@ -1191,6 +1194,7 @@ def main():
>      global insnmask
>      global decode_function
>      global variablewidth
> +    global anyextern
>
>      decode_scope = 'static '
>
> @@ -1251,6 +1255,19 @@ def main():
>      # A single translate function can be invoked for different patterns.
>      # Make sure that the argument sets are the same, and declare the
>      # function only once.
> +    #
> +    # If we're sharing formats, we're likely also sharing trans_* functions,
> +    # but we can't tell which ones.  Prevent issues from the compiler by
> +    # suppressing redundant declaration warnings.
> +    if anyextern:
> +        output("#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE\n",
> +               "# pragma GCC diagnostic push\n",
> +               "# pragma GCC diagnostic ignored \"-Wredundant-decls\"\n",
> +               "# ifdef __clang__\n"
> +               "#  pragma GCC diagnostic ignored \"-Wtypedef-redefinition\"\n",
> +               "# endif\n",
> +               "#endif\n\n")
> +
>      out_pats = {}
>      for i in allpatterns:
>          if i.name in out_pats:
> @@ -1262,6 +1279,11 @@ def main():
>              out_pats[i.name] = i
>      output('\n')
>
> +    if anyextern:
> +        output("#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE\n",
> +               "# pragma GCC diagnostic pop\n",
> +               "#endif\n\n")
> +
>      for n in sorted(formats.keys()):
>          f = formats[n]
>          f.output_extract()
> --
> 2.17.1
>
>