[PATCH 2/3] lto: support --jobserver-style=fifo for recent GNU make

[PATCH 2/3] lto: support --jobserver-style=fifo for recent GNU make

[Martin Liška]

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin

gcc/ChangeLog:

	* jobserver.h (jobserver_info::jobserver_info): Parse FIFO
	format of --jobserver-auth.
---
 gcc/jobserver.h | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/gcc/jobserver.h b/gcc/jobserver.h
index 85453dd3c79..856e326ddfc 100644
--- a/gcc/jobserver.h
+++ b/gcc/jobserver.h
@@ -39,14 +39,22 @@ struct jobserver_info
   int rfd = -1;
   /* File descriptor for writing used for jobserver communication.  */
   int wfd = -1;
+  /* Named pipe path.  */
+  string pipe_path = "";
   /* Return true if jobserver is active.  */
   bool is_active = false;
 };
 
 jobserver_info::jobserver_info ()
 {
+  /* Traditionally, GNU make uses opened pipes for jobserver-auth,
+    e.g. --jobserver-auth=3,4.
+    Starting with GNU make 4.4, one can use --jobserver-style=fifo
+    and then named pipe is used: --jobserver-auth=fifo:/tmp/hcsparta.  */
+
   /* Detect jobserver and drop it if it's not working.  */
   string js_needle = "--jobserver-auth=";
+  string fifo_prefix = "fifo:";
 
   const char *envval = getenv ("MAKEFLAGS");
   if (envval != NULL)
@@ -55,8 +63,15 @@ jobserver_info::jobserver_info ()
       size_t n = makeflags.rfind (js_needle);
       if (n != string::npos)
 	{
-	  if (sscanf (makeflags.c_str () + n + js_needle.size (),
-		      "%d,%d", &rfd, &wfd) == 2
+	  string ending = makeflags.substr (n + js_needle.size ());
+	  if (ending.find (fifo_prefix) == 0)
+	    {
+	      ending = ending.substr (fifo_prefix.size ());
+	      pipe_path = ending.substr (0, ending.find (' '));
+	      is_active = true;
+	    }
+	  else if (sscanf (makeflags.c_str () + n + js_needle.size (),
+			   "%d,%d", &rfd, &wfd) == 2
 	      && rfd > 0
 	      && wfd > 0
 	      && is_valid_fd (rfd)
-- 
2.37.1

[PATCH 3/3] lto: respect jobserver in parallel WPA streaming

[Martin Liška]

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin

	PR lto/106328

gcc/ChangeLog:

	* jobserver.h (struct jobserver_info): Add pipefd.
	(jobserver_info::connect): New.
	(jobserver_info::disconnect): Likewise.
	(jobserver_info::get_token): Likewise.
	(jobserver_info::return_token): Likewise.

gcc/lto/ChangeLog:

	* lto.cc (wait_for_child): Decrement nruns once a process
	finishes.
	(stream_out_partitions): Use job server if active.
	(do_whole_program_analysis): Likewise.
---
 gcc/jobserver.h | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
 gcc/lto/lto.cc  | 55 +++++++++++++++++++++++++++++++++++++------------
 2 files changed, 96 insertions(+), 13 deletions(-)

diff --git a/gcc/jobserver.h b/gcc/jobserver.h
index 856e326ddfc..2a7dc9f4113 100644
--- a/gcc/jobserver.h
+++ b/gcc/jobserver.h
@@ -31,6 +31,18 @@ struct jobserver_info
   /* Default constructor.  */
   jobserver_info ();
 
+  /* Connect to the server.  */
+  void connect ();
+
+  /* Disconnect from the server.  */
+  void disconnect ();
+
+  /* Get token from the server.  */
+  bool get_token ();
+
+  /* Return token to the server.  */
+  void return_token ();
+
   /* Error message if there is a problem.  */
   string error_msg = "";
   /* Skipped MAKEFLAGS where --jobserver-auth is skipped.  */
@@ -41,6 +53,8 @@ struct jobserver_info
   int wfd = -1;
   /* Named pipe path.  */
   string pipe_path = "";
+  /* Pipe file descriptor.  */
+  int pipefd = -1;
   /* Return true if jobserver is active.  */
   bool is_active = false;
 };
@@ -97,4 +111,44 @@ jobserver_info::jobserver_info ()
     error_msg = "jobserver is not available: " + error_msg;
 }
 
+void
+jobserver_info::connect ()
+{
+  if (!pipe_path.empty ())
+    pipefd = open (pipe_path.c_str (), O_RDWR);
+}
+
+void
+jobserver_info::disconnect ()
+{
+  if (!pipe_path.empty ())
+    {
+      gcc_assert (close (pipefd) == 0);
+      pipefd = -1;
+    }
+}
+
+bool
+jobserver_info::get_token ()
+{
+  int fd = pipe_path.empty () ? rfd : pipefd;
+  char c;
+  unsigned n = read (fd, &c, 1);
+  if (n != 1)
+    {
+      gcc_assert (errno == EAGAIN);
+      return false;
+    }
+  else
+    return true;
+}
+
+void
+jobserver_info::return_token ()
+{
+  int fd = pipe_path.empty () ? wfd : pipefd;
+  char c = 'G';
+  gcc_assert (write (fd, &c, 1) == 1);
+}
+
 #endif /* GCC_JOBSERVER_H */
diff --git a/gcc/lto/lto.cc b/gcc/lto/lto.cc
index 31b0c1862f7..56266195ead 100644
--- a/gcc/lto/lto.cc
+++ b/gcc/lto/lto.cc
@@ -54,11 +54,17 @@ along with GCC; see the file COPYING3.  If not see
 #include "attribs.h"
 #include "builtins.h"
 #include "lto-common.h"
-
+#include "jobserver.h"
 
 /* Number of parallel tasks to run, -1 if we want to use GNU Make jobserver.  */
 static int lto_parallelism;
 
+/* Number of active WPA streaming processes.  */
+static int nruns = 0;
+
+/* GNU make's jobserver info.  */
+static jobserver_info *jinfo = NULL;
+
 /* Return true when NODE has a clone that is analyzed (i.e. we need
    to load its body even if the node itself is not needed).  */
 
@@ -205,6 +211,12 @@ wait_for_child ()
 		     "streaming subprocess was killed by signal");
     }
   while (!WIFEXITED (status) && !WIFSIGNALED (status));
+
+    --nruns;
+
+    /* Return token to the jobserver if active.  */
+    if (jinfo != NULL && jinfo->is_active)
+      jinfo->return_token ();
 }
 #endif
 
@@ -228,25 +240,35 @@ stream_out_partitions (char *temp_filename, int blen, int min, int max,
 		       bool ARG_UNUSED (last))
 {
 #ifdef HAVE_WORKING_FORK
-  static int nruns;
-
   if (lto_parallelism <= 1)
     {
       stream_out_partitions_1 (temp_filename, blen, min, max);
       return;
     }
 
-  /* Do not run more than LTO_PARALLELISM streamings
-     FIXME: we ignore limits on jobserver.  */
   if (lto_parallelism > 0 && nruns >= lto_parallelism)
-    {
-      wait_for_child ();
-      nruns --;
-    }
+    wait_for_child ();
+
   /* If this is not the last parallel partition, execute new
      streaming process.  */
   if (!last)
     {
+      if (jinfo != NULL && jinfo->is_active)
+	while (true)
+	  {
+	    if (jinfo->get_token ())
+	      break;
+	    if (nruns > 0)
+	      wait_for_child ();
+	    else
+	      {
+		/* There are no free tokens, lets do the job outselves.  */
+		stream_out_partitions_1 (temp_filename, blen, min, max);
+		asm_nodes_output = true;
+		return;
+	      }
+	  }
+
       pid_t cpid = fork ();
 
       if (!cpid)
@@ -264,10 +286,12 @@ stream_out_partitions (char *temp_filename, int blen, int min, int max,
   /* Last partition; stream it and wait for all children to die.  */
   else
     {
-      int i;
       stream_out_partitions_1 (temp_filename, blen, min, max);
-      for (i = 0; i < nruns; i++)
+      while (nruns > 0)
 	wait_for_child ();
+
+      if (jinfo != NULL && jinfo->is_active)
+	jinfo->disconnect ();
     }
   asm_nodes_output = true;
 #else
@@ -460,9 +484,14 @@ do_whole_program_analysis (void)
 
   lto_parallelism = 1;
 
-  /* TODO: jobserver communication is not supported, yet.  */
   if (!strcmp (flag_wpa, "jobserver"))
-    lto_parallelism = param_max_lto_streaming_parallelism;
+    {
+      jinfo = new jobserver_info ();
+      if (jinfo->is_active)
+	jinfo->connect ();
+
+      lto_parallelism = param_max_lto_streaming_parallelism;
+    }
   else
     {
       lto_parallelism = atoi (flag_wpa);
-- 
2.37.1

Re: [PATCH 3/3] lto: respect jobserver in parallel WPA streaming

[Richard Biener]

On Tue, Aug 9, 2022 at 2:02 PM Martin Liška <mliska@suse.cz> wrote:
>
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>
> Ready to be installed?
> Thanks,
> Martin
>
>         PR lto/106328
>
> gcc/ChangeLog:
>
>         * jobserver.h (struct jobserver_info): Add pipefd.
>         (jobserver_info::connect): New.
>         (jobserver_info::disconnect): Likewise.
>         (jobserver_info::get_token): Likewise.
>         (jobserver_info::return_token): Likewise.
>
> gcc/lto/ChangeLog:
>
>         * lto.cc (wait_for_child): Decrement nruns once a process
>         finishes.
>         (stream_out_partitions): Use job server if active.
>         (do_whole_program_analysis): Likewise.
> ---
>  gcc/jobserver.h | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
>  gcc/lto/lto.cc  | 55 +++++++++++++++++++++++++++++++++++++------------
>  2 files changed, 96 insertions(+), 13 deletions(-)
>
> diff --git a/gcc/jobserver.h b/gcc/jobserver.h
> index 856e326ddfc..2a7dc9f4113 100644
> --- a/gcc/jobserver.h
> +++ b/gcc/jobserver.h
> @@ -31,6 +31,18 @@ struct jobserver_info
>    /* Default constructor.  */
>    jobserver_info ();
>
> +  /* Connect to the server.  */
> +  void connect ();
> +
> +  /* Disconnect from the server.  */
> +  void disconnect ();
> +
> +  /* Get token from the server.  */
> +  bool get_token ();
> +
> +  /* Return token to the server.  */
> +  void return_token ();
> +
>    /* Error message if there is a problem.  */
>    string error_msg = "";
>    /* Skipped MAKEFLAGS where --jobserver-auth is skipped.  */
> @@ -41,6 +53,8 @@ struct jobserver_info
>    int wfd = -1;
>    /* Named pipe path.  */
>    string pipe_path = "";
> +  /* Pipe file descriptor.  */
> +  int pipefd = -1;
>    /* Return true if jobserver is active.  */
>    bool is_active = false;
>  };
> @@ -97,4 +111,44 @@ jobserver_info::jobserver_info ()
>      error_msg = "jobserver is not available: " + error_msg;
>  }
>
> +void
> +jobserver_info::connect ()
> +{
> +  if (!pipe_path.empty ())
> +    pipefd = open (pipe_path.c_str (), O_RDWR);
> +}
> +
> +void
> +jobserver_info::disconnect ()

If it's not a template and the methods not inline won't we get multiple
definition errors when this include file is included in multiple places
from an executable?  opts-common.cc might be a good place to
stuff it, and opts.h to declare (if it were not for std::string, so possibly
jobserver.h is good enough, or opts-jobserver.h?)

> +{
> +  if (!pipe_path.empty ())
> +    {
> +      gcc_assert (close (pipefd) == 0);
> +      pipefd = -1;
> +    }
> +}
> +
> +bool
> +jobserver_info::get_token ()
> +{
> +  int fd = pipe_path.empty () ? rfd : pipefd;
> +  char c;
> +  unsigned n = read (fd, &c, 1);
> +  if (n != 1)
> +    {
> +      gcc_assert (errno == EAGAIN);
> +      return false;
> +    }
> +  else
> +    return true;
> +}
> +
> +void
> +jobserver_info::return_token ()
> +{
> +  int fd = pipe_path.empty () ? wfd : pipefd;
> +  char c = 'G';
> +  gcc_assert (write (fd, &c, 1) == 1);
> +}
> +
>  #endif /* GCC_JOBSERVER_H */
> diff --git a/gcc/lto/lto.cc b/gcc/lto/lto.cc
> index 31b0c1862f7..56266195ead 100644
> --- a/gcc/lto/lto.cc
> +++ b/gcc/lto/lto.cc
> @@ -54,11 +54,17 @@ along with GCC; see the file COPYING3.  If not see
>  #include "attribs.h"
>  #include "builtins.h"
>  #include "lto-common.h"
> -
> +#include "jobserver.h"
>
>  /* Number of parallel tasks to run, -1 if we want to use GNU Make jobserver.  */
>  static int lto_parallelism;
>
> +/* Number of active WPA streaming processes.  */
> +static int nruns = 0;
> +
> +/* GNU make's jobserver info.  */
> +static jobserver_info *jinfo = NULL;
> +
>  /* Return true when NODE has a clone that is analyzed (i.e. we need
>     to load its body even if the node itself is not needed).  */
>
> @@ -205,6 +211,12 @@ wait_for_child ()
>                      "streaming subprocess was killed by signal");
>      }
>    while (!WIFEXITED (status) && !WIFSIGNALED (status));
> +
> +    --nruns;
> +
> +    /* Return token to the jobserver if active.  */
> +    if (jinfo != NULL && jinfo->is_active)
> +      jinfo->return_token ();
>  }
>  #endif
>
> @@ -228,25 +240,35 @@ stream_out_partitions (char *temp_filename, int blen, int min, int max,
>                        bool ARG_UNUSED (last))
>  {
>  #ifdef HAVE_WORKING_FORK
> -  static int nruns;
> -
>    if (lto_parallelism <= 1)
>      {
>        stream_out_partitions_1 (temp_filename, blen, min, max);
>        return;
>      }
>
> -  /* Do not run more than LTO_PARALLELISM streamings
> -     FIXME: we ignore limits on jobserver.  */
>    if (lto_parallelism > 0 && nruns >= lto_parallelism)
> -    {
> -      wait_for_child ();
> -      nruns --;
> -    }
> +    wait_for_child ();
> +
>    /* If this is not the last parallel partition, execute new
>       streaming process.  */
>    if (!last)
>      {
> +      if (jinfo != NULL && jinfo->is_active)
> +       while (true)
> +         {
> +           if (jinfo->get_token ())
> +             break;
> +           if (nruns > 0)
> +             wait_for_child ();
> +           else
> +             {
> +               /* There are no free tokens, lets do the job outselves.  */
> +               stream_out_partitions_1 (temp_filename, blen, min, max);
> +               asm_nodes_output = true;
> +               return;
> +             }
> +         }
> +
>        pid_t cpid = fork ();
>
>        if (!cpid)
> @@ -264,10 +286,12 @@ stream_out_partitions (char *temp_filename, int blen, int min, int max,
>    /* Last partition; stream it and wait for all children to die.  */
>    else
>      {
> -      int i;
>        stream_out_partitions_1 (temp_filename, blen, min, max);
> -      for (i = 0; i < nruns; i++)
> +      while (nruns > 0)
>         wait_for_child ();
> +
> +      if (jinfo != NULL && jinfo->is_active)
> +       jinfo->disconnect ();
>      }
>    asm_nodes_output = true;
>  #else
> @@ -460,9 +484,14 @@ do_whole_program_analysis (void)
>
>    lto_parallelism = 1;
>
> -  /* TODO: jobserver communication is not supported, yet.  */
>    if (!strcmp (flag_wpa, "jobserver"))
> -    lto_parallelism = param_max_lto_streaming_parallelism;
> +    {
> +      jinfo = new jobserver_info ();
> +      if (jinfo->is_active)
> +       jinfo->connect ();
> +
> +      lto_parallelism = param_max_lto_streaming_parallelism;
> +    }
>    else
>      {
>        lto_parallelism = atoi (flag_wpa);
> --
> 2.37.1
>

Re: [PATCH 3/3] lto: respect jobserver in parallel WPA streaming

[Martin Liška]

[-- Attachment #1: Type: text/plain, Size: 419 bytes --]

On 8/10/22 12:52, Richard Biener wrote:
> If it's not a template and the methods not inline won't we get multiple
> definition errors when this include file is included in multiple places
> from an executable?  opts-common.cc might be a good place to
> stuff it, and opts.h to declare (if it were not for std::string, so possibly
> jobserver.h is good enough, or opts-jobserver.h?)

Works for me, updated in v2.

Martin

[-- Attachment #2: 0003-lto-respect-jobserver-in-parallel-WPA-streaming.patch --]
[-- Type: text/x-patch, Size: 6066 bytes --]

From ff2073e1f549df40a5e859e2cde9a403307c1960 Mon Sep 17 00:00:00 2001
From: Martin Liska <mliska@suse.cz>
Date: Tue, 9 Aug 2022 13:59:39 +0200
Subject: [PATCH 3/3] lto: respect jobserver in parallel WPA streaming

	PR lto/106328

gcc/ChangeLog:

	* opts-jobserver.h (struct jobserver_info): Add pipefd.
	(jobserver_info::connect): New.
	(jobserver_info::disconnect): Likewise.
	(jobserver_info::get_token): Likewise.
	(jobserver_info::return_token): Likewise.
	* opts-common.cc: Implement the new functions.

gcc/lto/ChangeLog:

	* lto.cc (wait_for_child): Decrement nruns once a process
	finishes.
	(stream_out_partitions): Use job server if active.
	(do_whole_program_analysis): Likewise.
---
 gcc/lto/lto.cc       | 58 +++++++++++++++++++++++++++++++++-----------
 gcc/opts-common.cc   | 42 ++++++++++++++++++++++++++++++++
 gcc/opts-jobserver.h | 14 +++++++++++
 3 files changed, 100 insertions(+), 14 deletions(-)

diff --git a/gcc/lto/lto.cc b/gcc/lto/lto.cc
index 31b0c1862f7..c82307f4f7e 100644
--- a/gcc/lto/lto.cc
+++ b/gcc/lto/lto.cc
@@ -18,6 +18,7 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#define INCLUDE_STRING
 #include "config.h"
 #include "system.h"
 #include "coretypes.h"
@@ -54,11 +55,17 @@ along with GCC; see the file COPYING3.  If not see
 #include "attribs.h"
 #include "builtins.h"
 #include "lto-common.h"
+#include "opts-jobserver.h"
 
-
-/* Number of parallel tasks to run, -1 if we want to use GNU Make jobserver.  */
+/* Number of parallel tasks to run.  */
 static int lto_parallelism;
 
+/* Number of active WPA streaming processes.  */
+static int nruns = 0;
+
+/* GNU make's jobserver info.  */
+static jobserver_info *jinfo = NULL;
+
 /* Return true when NODE has a clone that is analyzed (i.e. we need
    to load its body even if the node itself is not needed).  */
 
@@ -205,6 +212,12 @@ wait_for_child ()
 		     "streaming subprocess was killed by signal");
     }
   while (!WIFEXITED (status) && !WIFSIGNALED (status));
+
+    --nruns;
+
+    /* Return token to the jobserver if active.  */
+    if (jinfo != NULL && jinfo->is_active)
+      jinfo->return_token ();
 }
 #endif
 
@@ -228,25 +241,35 @@ stream_out_partitions (char *temp_filename, int blen, int min, int max,
 		       bool ARG_UNUSED (last))
 {
 #ifdef HAVE_WORKING_FORK
-  static int nruns;
-
   if (lto_parallelism <= 1)
     {
       stream_out_partitions_1 (temp_filename, blen, min, max);
       return;
     }
 
-  /* Do not run more than LTO_PARALLELISM streamings
-     FIXME: we ignore limits on jobserver.  */
   if (lto_parallelism > 0 && nruns >= lto_parallelism)
-    {
-      wait_for_child ();
-      nruns --;
-    }
+    wait_for_child ();
+
   /* If this is not the last parallel partition, execute new
      streaming process.  */
   if (!last)
     {
+      if (jinfo != NULL && jinfo->is_active)
+	while (true)
+	  {
+	    if (jinfo->get_token ())
+	      break;
+	    if (nruns > 0)
+	      wait_for_child ();
+	    else
+	      {
+		/* There are no free tokens, lets do the job outselves.  */
+		stream_out_partitions_1 (temp_filename, blen, min, max);
+		asm_nodes_output = true;
+		return;
+	      }
+	  }
+
       pid_t cpid = fork ();
 
       if (!cpid)
@@ -264,10 +287,12 @@ stream_out_partitions (char *temp_filename, int blen, int min, int max,
   /* Last partition; stream it and wait for all children to die.  */
   else
     {
-      int i;
       stream_out_partitions_1 (temp_filename, blen, min, max);
-      for (i = 0; i < nruns; i++)
+      while (nruns > 0)
 	wait_for_child ();
+
+      if (jinfo != NULL && jinfo->is_active)
+	jinfo->disconnect ();
     }
   asm_nodes_output = true;
 #else
@@ -460,9 +485,14 @@ do_whole_program_analysis (void)
 
   lto_parallelism = 1;
 
-  /* TODO: jobserver communication is not supported, yet.  */
   if (!strcmp (flag_wpa, "jobserver"))
-    lto_parallelism = param_max_lto_streaming_parallelism;
+    {
+      jinfo = new jobserver_info ();
+      if (jinfo->is_active)
+	jinfo->connect ();
+
+      lto_parallelism = param_max_lto_streaming_parallelism;
+    }
   else
     {
       lto_parallelism = atoi (flag_wpa);
diff --git a/gcc/opts-common.cc b/gcc/opts-common.cc
index c2993f9140a..6c9355f6372 100644
--- a/gcc/opts-common.cc
+++ b/gcc/opts-common.cc
@@ -2059,3 +2059,45 @@ jobserver_info::jobserver_info ()
   if (!error_msg.empty ())
     error_msg = "jobserver is not available: " + error_msg;
 }
+
+void
+jobserver_info::connect ()
+{
+  if (!pipe_path.empty ())
+    pipefd = open (pipe_path.c_str (), O_RDWR);
+}
+
+void
+jobserver_info::disconnect ()
+{
+  if (!pipe_path.empty ())
+    {
+      gcc_assert (close (pipefd) == 0);
+      pipefd = -1;
+    }
+}
+
+bool
+jobserver_info::get_token ()
+{
+  int fd = pipe_path.empty () ? rfd : pipefd;
+  char c;
+  unsigned n = read (fd, &c, 1);
+  if (n != 1)
+    {
+      gcc_assert (errno == EAGAIN);
+      return false;
+    }
+  else
+    return true;
+}
+
+void
+jobserver_info::return_token ()
+{
+  int fd = pipe_path.empty () ? wfd : pipefd;
+  char c = 'G';
+  gcc_assert (write (fd, &c, 1) == 1);
+}
+
+
diff --git a/gcc/opts-jobserver.h b/gcc/opts-jobserver.h
index 98ea2579962..76c1d9b2882 100644
--- a/gcc/opts-jobserver.h
+++ b/gcc/opts-jobserver.h
@@ -29,6 +29,18 @@ struct jobserver_info
   /* Default constructor.  */
   jobserver_info ();
 
+  /* Connect to the server.  */
+  void connect ();
+
+  /* Disconnect from the server.  */
+  void disconnect ();
+
+  /* Get token from the server.  */
+  bool get_token ();
+
+  /* Return token to the server.  */
+  void return_token ();
+
   /* Error message if there is a problem.  */
   string error_msg = "";
   /* Skipped MAKEFLAGS where --jobserver-auth is skipped.  */
@@ -39,6 +51,8 @@ struct jobserver_info
   int wfd = -1;
   /* Named pipe path.  */
   string pipe_path = "";
+  /* Pipe file descriptor.  */
+  int pipefd = -1;
   /* Return true if jobserver is active.  */
   bool is_active = false;
 };
-- 
2.37.1

Re: [PATCH 2/3] lto: support --jobserver-style=fifo for recent GNU make

[Martin Liška]

[-- Attachment #1: Type: text/plain, Size: 294 bytes --]

On 8/9/22 14:00, Martin Liška wrote:
> |Patch can bootstrap on x86_64-linux-gnu and survives regression tests. Ready to be installed? Thanks, Martin|

Sending v2 where I renamed the file. I'm going to install it as the original fifo support
patch was already approved by Richi.

Cheers,
Martin

[-- Attachment #2: 0002-lto-support-jobserver-style-fifo-for-recent-GNU-make.patch --]
[-- Type: text/x-patch, Size: 2324 bytes --]

From 4a678594435e2133166fad7cdc7ed144205455ff Mon Sep 17 00:00:00 2001
From: Martin Liska <mliska@suse.cz>
Date: Tue, 9 Aug 2022 13:59:36 +0200
Subject: [PATCH 2/3] lto: support --jobserver-style=fifo for recent GNU make

gcc/ChangeLog:

	* opts-jobserver.h: Add one member.
	* opts-common.cc (jobserver_info::jobserver_info): Parse FIFO
	format of --jobserver-auth.
---
 gcc/opts-common.cc   | 17 +++++++++++++++--
 gcc/opts-jobserver.h |  2 ++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/gcc/opts-common.cc b/gcc/opts-common.cc
index 4d4f424df13..c2993f9140a 100644
--- a/gcc/opts-common.cc
+++ b/gcc/opts-common.cc
@@ -2010,8 +2010,14 @@ void prepend_xassembler_to_collect_as_options (const char *collect_as_options,
 
 jobserver_info::jobserver_info ()
 {
+  /* Traditionally, GNU make uses opened pipes for jobserver-auth,
+    e.g. --jobserver-auth=3,4.
+    Starting with GNU make 4.4, one can use --jobserver-style=fifo
+    and then named pipe is used: --jobserver-auth=fifo:/tmp/hcsparta.  */
+
   /* Detect jobserver and drop it if it's not working.  */
   string js_needle = "--jobserver-auth=";
+  string fifo_prefix = "fifo:";
 
   const char *envval = getenv ("MAKEFLAGS");
   if (envval != NULL)
@@ -2020,8 +2026,15 @@ jobserver_info::jobserver_info ()
       size_t n = makeflags.rfind (js_needle);
       if (n != string::npos)
 	{
-	  if (sscanf (makeflags.c_str () + n + js_needle.size (),
-		      "%d,%d", &rfd, &wfd) == 2
+	  string ending = makeflags.substr (n + js_needle.size ());
+	  if (ending.find (fifo_prefix) == 0)
+	    {
+	      ending = ending.substr (fifo_prefix.size ());
+	      pipe_path = ending.substr (0, ending.find (' '));
+	      is_active = true;
+	    }
+	  else if (sscanf (makeflags.c_str () + n + js_needle.size (),
+			   "%d,%d", &rfd, &wfd) == 2
 	      && rfd > 0
 	      && wfd > 0
 	      && is_valid_fd (rfd)
diff --git a/gcc/opts-jobserver.h b/gcc/opts-jobserver.h
index 68ce188b84a..98ea2579962 100644
--- a/gcc/opts-jobserver.h
+++ b/gcc/opts-jobserver.h
@@ -37,6 +37,8 @@ struct jobserver_info
   int rfd = -1;
   /* File descriptor for writing used for jobserver communication.  */
   int wfd = -1;
+  /* Named pipe path.  */
+  string pipe_path = "";
   /* Return true if jobserver is active.  */
   bool is_active = false;
 };
-- 
2.37.1