[PATCH 1/3] Factor out jobserver_active_p.

["Martin Liška" <mliska@suse.cz>]

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

Ready to be installed?
Thanks,
Martin

gcc/ChangeLog:

	* gcc.cc (driver::detect_jobserver): Remove and move to
	jobserver.h.
	* lto-wrapper.cc (jobserver_active_p): Likewise.
	(run_gcc): Likewise.
	* jobserver.h: New file.
---
 gcc/gcc.cc         | 36 +++-----------------
 gcc/jobserver.h    | 85 ++++++++++++++++++++++++++++++++++++++++++++++
 gcc/lto-wrapper.cc | 43 +++++------------------
 3 files changed, 97 insertions(+), 67 deletions(-)
 create mode 100644 gcc/jobserver.h

diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index 5cbb38560b2..69fbd293eaa 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -43,6 +43,7 @@ compilation is specified by a string called a "spec".  */
 #include "opts.h"
 #include "filenames.h"
 #include "spellcheck.h"
+#include "jobserver.h"
 
 \f
 
@@ -9178,38 +9179,9 @@ driver::final_actions () const
 void
 driver::detect_jobserver () const
 {
-  /* Detect jobserver and drop it if it's not working.  */
-  const char *makeflags = env.get ("MAKEFLAGS");
-  if (makeflags != NULL)
-    {
-      const char *needle = "--jobserver-auth=";
-      const char *n = strstr (makeflags, needle);
-      if (n != NULL)
-	{
-	  int rfd = -1;
-	  int wfd = -1;
-
-	  bool jobserver
-	    = (sscanf (n + strlen (needle), "%d,%d", &rfd, &wfd) == 2
-	       && rfd > 0
-	       && wfd > 0
-	       && is_valid_fd (rfd)
-	       && is_valid_fd (wfd));
-
-	  /* Drop the jobserver if it's not working now.  */
-	  if (!jobserver)
-	    {
-	      unsigned offset = n - makeflags;
-	      char *dup = xstrdup (makeflags);
-	      dup[offset] = '\0';
-
-	      const char *space = strchr (makeflags + offset, ' ');
-	      if (space != NULL)
-		strcpy (dup + offset, space);
-	      xputenv (concat ("MAKEFLAGS=", dup, NULL));
-	    }
-	}
-    }
+  jobserver_info jinfo;
+  if (!jinfo.is_active && !jinfo.skipped_makeflags.empty ())
+    xputenv (jinfo.skipped_makeflags.c_str ());
 }
 
 /* Determine what the exit code of the driver should be.  */
diff --git a/gcc/jobserver.h b/gcc/jobserver.h
new file mode 100644
index 00000000000..85453dd3c79
--- /dev/null
+++ b/gcc/jobserver.h
@@ -0,0 +1,85 @@
+/* GNU make's jobserver related functionality.
+   Copyright (C) 2022 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
+<http://www.gnu.org/licenses/>.
+
+See dbgcnt.def for usage information.  */
+
+#ifndef GCC_JOBSERVER_H
+#define GCC_JOBSERVER_H
+
+#include <string>
+
+using namespace std;
+
+struct jobserver_info
+{
+  /* Default constructor.  */
+  jobserver_info ();
+
+  /* Error message if there is a problem.  */
+  string error_msg = "";
+  /* Skipped MAKEFLAGS where --jobserver-auth is skipped.  */
+  string skipped_makeflags = "";
+  /* File descriptor for reading used for jobserver communication.  */
+  int rfd = -1;
+  /* File descriptor for writing used for jobserver communication.  */
+  int wfd = -1;
+  /* Return true if jobserver is active.  */
+  bool is_active = false;
+};
+
+jobserver_info::jobserver_info ()
+{
+  /* Detect jobserver and drop it if it's not working.  */
+  string js_needle = "--jobserver-auth=";
+
+  const char *envval = getenv ("MAKEFLAGS");
+  if (envval != NULL)
+    {
+      string makeflags = envval;
+      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
+	      && rfd > 0
+	      && wfd > 0
+	      && is_valid_fd (rfd)
+	      && is_valid_fd (wfd))
+	    is_active = true;
+	  else
+	    {
+	      string dup = makeflags.substr (0, n);
+	      size_t pos = makeflags.find (' ', n);
+	      if (pos != string::npos)
+		dup += makeflags.substr (pos);
+	      skipped_makeflags = "MAKEFLAGS=" + dup;
+	      error_msg
+		= "cannot access %<" + js_needle + "%> file descriptors";
+	    }
+	}
+      error_msg = "%<" + js_needle + "%> is not present in %<MAKEFLAGS%>";
+    }
+  else
+    error_msg = "%<MAKEFLAGS%> environment variable is unset";
+
+  if (!error_msg.empty ())
+    error_msg = "jobserver is not available: " + error_msg;
+}
+
+#endif /* GCC_JOBSERVER_H */
diff --git a/gcc/lto-wrapper.cc b/gcc/lto-wrapper.cc
index 795ab74555c..9279958d055 100644
--- a/gcc/lto-wrapper.cc
+++ b/gcc/lto-wrapper.cc
@@ -49,6 +49,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "lto-section-names.h"
 #include "collect-utils.h"
 #include "opts-diagnostic.h"
+#include "opt-suggestions.h"
+#include "jobserver.h"
 
 /* Environment variable, used for passing the names of offload targets from GCC
    driver to lto-wrapper.  */
@@ -1336,35 +1338,6 @@ init_num_threads (void)
 #endif
 }
 
-/* Test and return reason why a jobserver cannot be detected.  */
-
-static const char *
-jobserver_active_p (void)
-{
-  #define JS_PREFIX "jobserver is not available: "
-  #define JS_NEEDLE "--jobserver-auth="
-
-  const char *makeflags = getenv ("MAKEFLAGS");
-  if (makeflags == NULL)
-    return JS_PREFIX "%<MAKEFLAGS%> environment variable is unset";
-
-  const char *n = strstr (makeflags, JS_NEEDLE);
-  if (n == NULL)
-    return JS_PREFIX "%<" JS_NEEDLE "%> is not present in %<MAKEFLAGS%>";
-
-  int rfd = -1;
-  int wfd = -1;
-
-  if (sscanf (n + strlen (JS_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";
-}
-
 /* Print link to -flto documentation with a hint message.  */
 
 void
@@ -1422,7 +1395,6 @@ run_gcc (unsigned argc, char *argv[])
   bool jobserver_requested = false;
   int auto_parallel = 0;
   bool no_partition = false;
-  const char *jobserver_error = NULL;
   bool fdecoded_options_first = true;
   vec<cl_decoded_option> fdecoded_options;
   fdecoded_options.create (16);
@@ -1653,14 +1625,14 @@ run_gcc (unsigned argc, char *argv[])
     }
   else
     {
-      jobserver_error = jobserver_active_p ();
-      if (jobserver && jobserver_error != NULL)
+      jobserver_info jinfo;
+      if (jobserver && !jinfo.is_active)
 	{
 	  /* Fall back to auto parallelism.  */
 	  jobserver = 0;
 	  auto_parallel = 1;
 	}
-      else if (!jobserver && jobserver_error == NULL)
+      else if (!jobserver && jinfo.is_active)
 	{
 	  parallel = 1;
 	  jobserver = 1;
@@ -1971,9 +1943,10 @@ cont:
 
       if (nr > 1)
 	{
-	  if (jobserver_requested && jobserver_error != NULL)
+	  jobserver_info jinfo;
+	  if (jobserver_requested && !jinfo.is_active)
 	    {
-	      warning (0, jobserver_error);
+	      warning (0, jinfo.error_msg.c_str ());
 	      print_lto_docs_link ();
 	    }
 	  else if (parallel == 0)
-- 
2.37.1