calls.c (special_function_p): New argument fork_or_exec.

gcc:
	* calls.c (special_function_p): New argument fork_or_exec.
	(expand_call): When profile_arc_flag is set and the function
	is in the fork_or_exec group, call __bb_fork_func first.
	* libgcc2.c, _bb module (__bb_fork_func): New function.
	(__bb_exit_func): If fcntl F_SETLKW is available, use it to lock
	output file.
	* config/svr4.h (TARGET_HAS_F_SETLKW): Define.
	* tree.h (special_function_p): Update prototype.

gcc/cp:
	* cp/optimize.c (calls_setjmp_r): Supply new argument
	to special_function_p.

From-SVN: r31635

gcc/ChangeLog

@@ -1,3 +1,14 @@
+Wed Jan 26 22:19:14 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
+
+	* calls.c (special_function_p): New argument fork_or_exec.
+	(expand_call): When profile_arc_flag is set and the function
+	is in the fork_or_exec group, call __bb_fork_func first.
+	* libgcc2.c, _bb module (__bb_fork_func): New function.
+	(__bb_exit_func): If fcntl F_SETLKW is available, use it to lock
+	output file.
+	* config/svr4.h (TARGET_HAS_F_SETLKW): Define.
+	* tree.h (special_function_p): Update prototype.
+
 2000-01-26  Richard Henderson  <rth@cygnus.com>
 
 	* alpha.c (alpha_split_tfmode_pair): New.

gcc/config/svr4.h

@@ -235,3 +235,4 @@ Boston, MA 02111-1307, USA.
    to support ANSI C.  */
 /* #define MULTIBYTE_CHARS */
 
+#define TARGET_HAS_F_SETLKW

gcc/cp/ChangeLog

@@ -1,3 +1,8 @@
+Wed Jan 26 22:19:14 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
+
+	* cp/optimize.c (calls_setjmp_r): Supply new argument
+	to special_function_p.
+
 2000-01-26  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* call.c: PROTO -> PARAMS.

gcc/cp/optimize.c

@@ -732,6 +732,7 @@ calls_setjmp_r (tp, walk_subtrees, data)
 {
   int setjmp_p;
   int longjmp_p;
+  int fork_or_exec_p;
   int malloc_p;
   int alloca_p;
 
@@ -739,7 +740,8 @@ calls_setjmp_r (tp, walk_subtrees, data)
   if (TREE_CODE (*tp) != FUNCTION_DECL)
     return NULL_TREE;
 
-  special_function_p (*tp, &setjmp_p, &longjmp_p, &malloc_p, &alloca_p);
+  special_function_p (*tp, &setjmp_p, &longjmp_p, &fork_or_exec_p, &malloc_p,
+		      &alloca_p);
 
   return setjmp_p ? *tp : NULL_TREE;
 }

gcc/libgcc2.c

@@ -1,6 +1,7 @@
 /* More subroutines needed by GCC output code on some machines.  */
 /* Compile this one with gcc.  */
-/* Copyright (C) 1989, 92-98, 1999 Free Software Foundation, Inc.
+/* Copyright (C) 1989, 92, 93, 94, 95, 96, 97, 98, 1999, 2000
+   Free Software Foundation, Inc.
 
 This file is part of GNU CC.
 
@@ -1563,6 +1564,10 @@ char *ctime ();
 #include "gbl-ctors.h"
 #include "gcov-io.h"
 #include <string.h>
+#ifdef TARGET_HAS_F_SETLKW
+#include <fcntl.h>
+#include <errno.h>
+#endif
 
 static struct bb *bb_head;
 
@@ -1606,13 +1611,64 @@ __bb_exit_func (void)
 
       for (ptr = bb_head; ptr != (struct bb *) 0; ptr = ptr->next)
 	{
-	  /* If the file exists, and the number of counts in it is the same,
-	     then merge them in.  */
-	     
-	  if ((da_file = fopen (ptr->filename, "rb")) != 0)
+	  int firstchar;
+
+	  /* Make sure the output file exists -
+	     but don't clobber exiting data.  */
+	  if ((da_file = fopen (ptr->filename, "a")) != 0)
+	    fclose (da_file);
+
+	  /* Need to re-open in order to be able to write from the start.  */
+	  da_file = fopen (ptr->filename, "r+b");
+	  /* Some old systems might not allow the 'b' mode modifier.
+	     Therefore, try to open without it.  This can lead to a race
+	     condition so that when you delete and re-create the file, the
+	     file might be opened in text mode, but then, you shouldn't
+	     delete the file in the first place.  */
+	  if (da_file == 0)
+	    da_file = fopen (ptr->filename, "r+");
+	  if (da_file == 0)
+	    {
+	      fprintf (stderr, "arc profiling: Can't open output file %s.\n",
+		       ptr->filename);
+	      continue;
+	    }
+
+	  /* After a fork, another process might try to read and/or write
+	     the same file simultanously.  So if we can, lock the file to
+	     avoid race conditions.  */
+#if defined (TARGET_HAS_F_SETLKW)
+	  {
+	    struct flock s_flock;
+
+	    s_flock.l_type = F_WRLCK;
+	    s_flock.l_whence = SEEK_SET;
+	    s_flock.l_start = 0;
+	    s_flock.l_len = 1;
+	    s_flock.l_pid = getpid ();
+
+	    while (fcntl (fileno (da_file), F_SETLKW, &s_flock)
+		   && errno == EINTR);
+	  }
+#endif
+
+	  /* If the file is not empty, and the number of counts in it is the
+	     same, then merge them in.  */
+	  firstchar = fgetc (da_file);
+	  if (firstchar == EOF)
+	    {
+	      if (ferror (da_file))
+		{
+		  fprintf (stderr, "arc profiling: Can't read output file ");
+		  perror (ptr->filename);
+		}
+	    }
+	  else
 	    {
 	      long n_counts = 0;
 	      
+	      if (ungetc (firstchar, da_file) == EOF)
+		rewind (da_file);
 	      if (__read_long (&n_counts, da_file, 8) != 0)
 		{
 		  fprintf (stderr, "arc profiling: Can't read output file %s.\n",
@@ -1638,17 +1694,10 @@ __bb_exit_func (void)
 		    }
 		}
 
-	      if (fclose (da_file) == EOF)
-		fprintf (stderr, "arc profiling: Error closing output file %s.\n",
-			 ptr->filename);
-	    }
-	  if ((da_file = fopen (ptr->filename, "wb")) == 0)
-	    {
-	      fprintf (stderr, "arc profiling: Can't open output file %s.\n",
-		       ptr->filename);
-	      continue;
 	    }
 
+	  rewind (da_file);
+
 	  /* ??? Should first write a header to the file.  Preferably, a 4 byte
 	     magic number, 4 bytes containing the time the program was
 	     compiled, 4 bytes containing the last modification time of the
@@ -1826,6 +1875,23 @@ __bb_init_func (struct bb *blocks)
   bb_head = blocks;
 }
 
+/* Called before fork or exec - write out profile information gathered so
+   far and reset it to zero.  This avoids duplication or loss of the
+   profile information gathered so far.  */
+void
+__bb_fork_func (void)
+{
+  struct bb *ptr;
+
+  __bb_exit_func ();
+  for (ptr = bb_head; ptr != (struct bb *) 0; ptr = ptr->next)
+    {
+      long i;
+      for (i = ptr->ncounts - 1; i >= 0; i--)
+	ptr->counts[i] = 0;
+    }
+}
+
 #ifndef MACHINE_STATE_SAVE
 #define MACHINE_STATE_SAVE(ID)
 #endif

gcc/tm.texi

@@ -7815,4 +7815,12 @@ specifies where the linker should look for libraries.
 
 You need only define this macro if the default of @samp{"LIBRARY_PATH"}
 is wrong.
+
+@findex TARGET_HAS_F_SETLKW
+@item TARGET_HAS_F_SETLKW
+Define this macro iff the target supports file locking with fcntl / F_SETLKW.
+Note that this functionality is part of POSIX.
+Defining @code{TARGET_HAS_F_SETLKW} will enable the test coverage code
+to use file locking when exiting a program, which avoids race conditions
+if the program has forked.
 @end table

gcc/tree.h

@@ -2431,7 +2431,7 @@ extern struct rtx_def *emit_line_note_force	PARAMS ((char *, int));
 
 /* In calls.c */
 extern void special_function_p	        PARAMS ((tree, int *, int *,
-						int *, int *));
+						int *, int *, int *));
 
 /* In c-typeck.c */
 extern int mark_addressable		PARAMS ((tree));