[SV 47995] Ensure forced double-colon rules work with -j.

The fix for SV 44742 had a side-effect that some double-colon targets
were skipped.  This happens because the "considered" facility assumed
that all targets would be visited on each walk through the dependency
graph: we used a bit for considered and toggled it on each pass; if
we didn't walk the entire graph on every pass the bit would get out
of sync.  The new behavior after SV 44742 might return early without
walking the entire graph.  To fix this I changed the considered value
to an integer which is monotonically increasing: it is then never
possible to incorrectly determine that a previous pass through the
graph already considered the current target.

* filedef.h (struct file): make CONSIDERED an unsigned int.
* main.c (main): No longer need to reset CONSIDERED.
* remake.c (update_goal_chain): increment CONSIDERED rather than
inverting it between 0<->1.
(update_file_1): Reset CONSIDERED to 0 so it's re-considered.
(check_dep): Ditto.
* tests/scripts/features/double_colon: Add a regression test.

4 files changed, 30 insertions, 18 deletions

diff --git a/filedef.h b/filedef.h
index 507a0279..14b41871 100644
--- a/filedef.h
+++ b/filedef.h
@@ -58,6 +58,8 @@ struct file
     FILE_TIMESTAMP last_mtime;  /* File's modtime, if already known.  */
     FILE_TIMESTAMP mtime_before_update; /* File's modtime before any updating
                                            has been performed.  */
+    unsigned int considered;    /* equal to 'considered' if file has been
+                                   considered on current scan of goal chain */
     int command_flags;          /* Flags OR'd in for cmds; see commands.h.  */
     enum update_status          /* Status of the last attempt to update.  */
       {
@@ -96,8 +98,6 @@ struct file
     unsigned int ignore_vpath:1;/* Nonzero if we threw out VPATH name.  */
     unsigned int pat_searched:1;/* Nonzero if we already searched for
                                    pattern-specific variables.  */
-    unsigned int considered:1;  /* equal to 'considered' if file has been
-                                   considered on current scan of goal chain */
     unsigned int no_diag:1;     /* True if the file failed to update and no
                                    diagnostics has been issued (dontcare). */
   };
diff --git a/main.c b/main.c
index 576f2e96..e6064880 100644
--- a/main.c
+++ b/main.c
@@ -2262,10 +2262,6 @@ main (int argc, char **argv, char **envp)
 
             for (i = 0, d = read_files; d != 0; ++i, d = d->next)
               {
-                /* Reset the considered flag; we may need to look at the file
-                   again to print an error.  */
-                d->file->considered = 0;
-
                 if (d->file->updated)
                   {
                     /* This makefile was updated.  */
diff --git a/remake.c b/remake.c
index df1a9e0d..5d5d67a4 100644
--- a/remake.c
+++ b/remake.c
@@ -57,8 +57,9 @@ unsigned int commands_started = 0;
 static struct goaldep *goal_list;
 static struct dep *goal_dep;
 
-/* Current value for pruning the scan of the goal chain (toggle 0/1).  */
-static unsigned int considered;
+/* Current value for pruning the scan of the goal chain.
+   All files start with considered == 0.  */
+static unsigned int considered = 0;
 
 static enum update_status update_file (struct file *file, unsigned int depth);
 static enum update_status update_file_1 (struct file *file, unsigned int depth);
@@ -90,12 +91,12 @@ update_goal_chain (struct goaldep *goaldeps)
 
   goal_list = rebuilding_makefiles ? goaldeps : NULL;
 
-  /* All files start with the considered bit 0, so the global value is 1.  */
-  considered = 1;
-
 #define MTIME(file) (rebuilding_makefiles ? file_mtime_no_search (file) \
                      : file_mtime (file))
 
+  /* Start a fresh batch of consideration.  */
+  ++considered;
+
   /* Update all the goals until they are all finished.  */
 
   while (goals != 0)
@@ -247,10 +248,10 @@ update_goal_chain (struct goaldep *goaldeps)
             }
         }
 
-      /* If we reached the end of the dependency graph toggle the considered
-         flag for the next pass.  */
+      /* If we reached the end of the dependency graph update CONSIDERED
+         for the next pass.  */
       if (g == 0)
-        considered = !considered;
+        ++considered;
     }
 
   if (rebuilding_makefiles)
@@ -615,8 +616,8 @@ update_file_1 (struct file *file, unsigned int depth)
             break;
 
           if (!running)
-            /* The prereq is considered changed if the timestamp has changed while
-               it was built, OR it doesn't exist.  */
+            /* The prereq is considered changed if the timestamp has changed
+               while it was built, OR it doesn't exist.  */
             d->changed = ((file_mtime (d->file) != mtime)
                           || (mtime == NONEXISTENT_MTIME));
 
@@ -650,7 +651,7 @@ update_file_1 (struct file *file, unsigned int depth)
             /* We may have already considered this file, when we didn't know
                we'd need to update it.  Force update_file() to consider it and
                not prune it.  */
-            d->file->considered = !considered;
+            d->file->considered = 0;
 
             new = update_file (d->file, depth);
             if (new > dep_status)
@@ -1087,7 +1088,7 @@ check_dep (struct file *file, unsigned int depth,
               /* If the target was waiting for a dependency it has to be
                  reconsidered, as that dependency might have finished.  */
               if (file->command_state == cs_deps_running)
-                file->considered = !considered;
+                file->considered = 0;
 
               set_command_state (file, cs_not_started);
             }
diff --git a/tests/scripts/features/double_colon b/tests/scripts/features/double_colon
index 80ddb319..58f126f6 100644
--- a/tests/scripts/features/double_colon
+++ b/tests/scripts/features/double_colon
@@ -197,6 +197,21 @@ all:: 3
 ',
               '-rs -j2 1 2 root', "all_one\nall_two\nroot\n");
 
+# SV 47995 : Parallel double-colon rules with FORCE
+
+run_make_test('
+all:: ; @echo one
+
+all:: joe ; @echo four
+
+joe: FORCE ; touch joe-is-forced
+
+FORCE:
+',
+              '-j5', "one\ntouch joe-is-forced\nfour\n");
+
+unlink('joe-is-forced');
+
 # This tells the test driver that the perl test script executed properly.
 1;