Re: [PATCH] lto: support --jobserver-style=fifo for recent GNU make

["Martin Liška" <mliska@suse.cz>]

On 8/5/22 12:58, Richard Biener wrote:
> On Thu, Aug 4, 2022 at 10:57 AM Martin Liška <mliska@suse.cz> wrote:
>>
>> After a long time, GNU make has finally implemented named pipes when
>> it comes to --jobserver-auth. The traditional approach are
>> provided opened file descriptors that causes troubles:
>> https://savannah.gnu.org/bugs/index.php?57242
>>
>> GNU make commit:
>> https://git.savannah.gnu.org/cgit/make.git/commit/?id=7ad2593b2d2bb5b9332f4444d8bf93ac6f958bc6
>>
>> I tested that locally with TOT GNU make and it works:
>>
>> $ cat Makefile
>> all:
>>         g++ tramp3d-v4.ii -c -flto -O2
>>         g++ tramp3d-v4.o -flto=jobserver
>>
>> $ MAKE=/tmp/bin/bin/make /tmp/bin/bin/make -j16 --jobserver-style=fifo
>> g++ tramp3d-v4.ii -c -flto -O2
>> g++ tramp3d-v4.o -flto=jobserver
>> (ltrans run in parallel)
>>
>> Ready to be installed after tests?
> 
> LGTM.

I've got actually a nicer patch set where I also support jobserver for WPA.
I'm going to send it in a separate thread.

Martin

> 
> Thanks,
> Richard.
> 
>> Martin
>>
>> gcc/ChangeLog:
>>
>>         * gcc.cc (driver::detect_jobserver): Support --jobserver-style=fifo.
>>         * lto-wrapper.cc (jobserver_active_p): Likewise.
>> ---
>>   gcc/gcc.cc         | 15 ++++++++++++---
>>   gcc/lto-wrapper.cc | 20 +++++++++++++++-----
>>   2 files changed, 27 insertions(+), 8 deletions(-)
>>
>> diff --git a/gcc/gcc.cc b/gcc/gcc.cc
>> index 5cbb38560b2..c98407fe03d 100644
>> --- a/gcc/gcc.cc
>> +++ b/gcc/gcc.cc
>> @@ -9182,15 +9182,24 @@ driver::detect_jobserver () const
>>     const char *makeflags = env.get ("MAKEFLAGS");
>>     if (makeflags != NULL)
>>       {
>> -      const char *needle = "--jobserver-auth=";
>> -      const char *n = strstr (makeflags, needle);
>> +      /* Traditionally, GNU make uses opened pieps for jobserver-auth,
>> +        e.g. --jobserver-auth=3,4.  */
>> +      const char *pipe_needle = "--jobserver-auth=";
>> +
>> +      /* Starting with GNU make 4.4, one can use --jobserver-style=fifo
>> +        and then named pipe is used: --jobserver-auth=fifo:/tmp/hcsparta.  */
>> +      const char *fifo_needle = "--jobserver-auth=fifo:";
>> +      if (strstr (makeflags, fifo_needle) != NULL)
>> +       return;
>> +
>> +      const char *n = strstr (makeflags, pipe_needle);
>>         if (n != NULL)
>>         {
>>           int rfd = -1;
>>           int wfd = -1;
>>
>>           bool jobserver
>> -           = (sscanf (n + strlen (needle), "%d,%d", &rfd, &wfd) == 2
>> +           = (sscanf (n + strlen (pipe_needle), "%d,%d", &rfd, &wfd) == 2
>>                && rfd > 0
>>                && wfd > 0
>>                && is_valid_fd (rfd)
>> diff --git a/gcc/lto-wrapper.cc b/gcc/lto-wrapper.cc
>> index 795ab74555c..756350d5ace 100644
>> --- a/gcc/lto-wrapper.cc
>> +++ b/gcc/lto-wrapper.cc
>> @@ -1342,27 +1342,37 @@ static const char *
>>   jobserver_active_p (void)
>>   {
>>     #define JS_PREFIX "jobserver is not available: "
>> -  #define JS_NEEDLE "--jobserver-auth="
>> +
>> +  /* Traditionally, GNU make uses opened pieps for jobserver-auth,
>> +     e.g. --jobserver-auth=3,4.  */
>> +  #define JS_PIPE_NEEDLE "--jobserver-auth="
>> +
>> +  /* Starting with GNU make 4.4, one can use --jobserver-style=fifo
>> +     and then named pipe is used: --jobserver-auth=fifo:/tmp/hcsparta.  */
>> +  #define JS_FIFO_NEEDLE "--jobserver-auth=fifo:"
>>
>>     const char *makeflags = getenv ("MAKEFLAGS");
>>     if (makeflags == NULL)
>>       return JS_PREFIX "%<MAKEFLAGS%> environment variable is unset";
>>
>> -  const char *n = strstr (makeflags, JS_NEEDLE);
>> +  if (strstr (makeflags, JS_FIFO_NEEDLE) != NULL)
>> +    return NULL;
>> +
>> +  const char *n = strstr (makeflags, JS_PIPE_NEEDLE);
>>     if (n == NULL)
>> -    return JS_PREFIX "%<" JS_NEEDLE "%> is not present in %<MAKEFLAGS%>";
>> +    return JS_PREFIX "%<" JS_PIPE_NEEDLE "%> is not present in %<MAKEFLAGS%>";
>>
>>     int rfd = -1;
>>     int wfd = -1;
>>
>> -  if (sscanf (n + strlen (JS_NEEDLE), "%d,%d", &rfd, &wfd) == 2
>> +  if (sscanf (n + strlen (JS_PIPE_NEEDLE), "%d,%d", &rfd, &wfd) == 2
>>         && rfd > 0
>>         && wfd > 0
>>         && is_valid_fd (rfd)
>>         && is_valid_fd (wfd))
>>       return NULL;
>>     else
>> -    return JS_PREFIX "cannot access %<" JS_NEEDLE "%> file descriptors";
>> +    return JS_PREFIX "cannot access %<" JS_PIPE_NEEDLE "%> file descriptors";
>>   }
>>
>>   /* Print link to -flto documentation with a hint message.  */
>> --
>> 2.37.1
>>