Initial patch for output synchronization. See Savannah bug #33138.

Based on work by David Boyce <David.S.Boyce@gmail.com>.

1 files changed, 32 insertions, 5 deletions

diff --git a/main.c b/main.c
index 0a2774c..0447888 100644
--- a/main.c
+++ b/main.c
@@ -228,6 +228,15 @@ static unsigned int master_job_slots = 0;
 
 static unsigned int inf_jobs = 0;
 
+#ifdef PARALLEL_SYNC
+
+/* Default value for parallel sync without an argument.  */
+
+static unsigned int no_parallel_sync = 0;
+static unsigned int default_parallel_sync = PARALLEL_SYNC_FINE;
+
+#endif
+
 /* File descriptors for the jobs pipe.  */
 
 static struct stringlist *jobserver_fds = 0;
@@ -344,6 +353,10 @@ static const char *const usage[] =
                               Consider FILE to be very old and don't remake it.\n"),
     N_("\
   -p, --print-data-base       Print make's internal database.\n"),
+#ifdef PARALLEL_SYNC
+    N_("\
+  -P [2], --parallel-sync[=2] Synchronize output of parallel jobs [coarse].\n"),
+#endif
     N_("\
   -q, --question              Run no recipe; exit status says if up to date.\n"),
     N_("\
@@ -408,6 +421,11 @@ static const struct command_switch switches[] =
     { 'n', flag, &just_print_flag, 1, 1, 1, 0, 0, "just-print" },
     { 'o', filename, &old_files, 0, 0, 0, 0, 0, "old-file" },
     { 'p', flag, &print_data_base_flag, 1, 1, 0, 0, 0, "print-data-base" },
+#ifdef PARALLEL_SYNC
+    // { 'P', flag, &parallel_sync, 1, 1, 0, 0, 0, "parallel-sync" },  // two-state
+    { 'P', positive_int, &parallel_sync, 1, 1, 0, &default_parallel_sync,
+      &no_parallel_sync, "parallel-sync" },
+#endif
     { 'q', flag, &question_flag, 1, 1, 1, 0, 0, "question" },
     { 'r', flag, &no_builtin_rules_flag, 1, 1, 0, 0, 0, "no-builtin-rules" },
     { 'R', flag, &no_builtin_variables_flag, 1, 1, 0, 0, 0,
@@ -503,6 +521,14 @@ int second_expansion;
 
 int one_shell;
 
+/* Either PARALLEL_SYNC_FINE or PARALLEL_SYNC_COARSE
+   if the "--parallel-sync" option was given.
+   This attempts to synchronize the output of parallel
+   jobs such that the results of each job stay together.
+   It works best in combination with .ONESHELL.  */
+
+int parallel_sync;
+
 /* Nonzero if we have seen the '.NOTPARALLEL' target.
    This turns off parallel builds for this invocation of make.  */
 
@@ -2095,7 +2121,7 @@ main (int argc, char **argv, char **envp)
           if (print_data_base_flag)
             print_data_base ();
 
-          log_working_directory (0);
+          log_working_directory (0, 0);
 
           clean_jobserver (0);
 
@@ -3280,7 +3306,7 @@ die (int status)
           _x = chdir (directory_before_chdir);
         }
 
-      log_working_directory (0);
+      log_working_directory (0, 0);
     }
 
   exit (status);
@@ -3290,17 +3316,18 @@ die (int status)
    left (according to ENTERING) the current directory.  */
 
 void
-log_working_directory (int entering)
+log_working_directory (int entering, int force)
 {
   static int entered = 0;
 
   /* Print nothing without the flag.  Don't print the entering message
      again if we already have.  Don't print the leaving message if we
      haven't printed the entering message.  */
-  if (! print_directory_flag || entering == entered)
+  if (! print_directory_flag || (!force && entering == entered))
     return;
 
-  entered = entering;
+  if (!force)
+    entered = entering;
 
   if (print_data_base_flag)
     fputs ("# ", stdout);