1 files changed, 28 insertions, 49 deletions

diff --git a/gcc/gcov-io.c b/gcc/gcov-io.c
index 17fcae0063..64dedd5528 100644
--- a/gcc/gcov-io.c
+++ b/gcc/gcov-io.c
@@ -1,5 +1,5 @@
 /* File format for coverage information
-   Copyright (C) 1996-2016 Free Software Foundation, Inc.
+   Copyright (C) 1996-2017 Free Software Foundation, Inc.
    Contributed by Bob Manson <manson@cygnus.com>.
    Completely remangled by Nathan Sidwell <nathan@codesourcery.com>.
 
@@ -115,10 +115,9 @@ static inline gcov_unsigned_t from_file (gcov_unsigned_t value)
    opened. If MODE is >= 0 an existing file will be opened, if
    possible, and if MODE is <= 0, a new file will be created. Use
    MODE=0 to attempt to reopen an existing file and then fall back on
-   creating a new one.  If MODE < 0, the file will be opened in
+   creating a new one.  If MODE > 0, the file will be opened in
    read-only mode.  Otherwise it will be opened for modification.
-   Return zero on failure, >0 on opening an existing file and <0 on
-   creating a new one.  */
+   Return zero on failure, non-zero on success.  */
 
 GCOV_LINKAGE int
 #if IN_LIBGCOV
@@ -128,7 +127,7 @@ gcov_open (const char *name, int mode)
 #endif
 {
 #if IN_LIBGCOV
-  const int mode = 0;
+  int mode = 0;
 #endif
 #if GCOV_LOCKED
   struct flock s_flock;
@@ -156,17 +155,12 @@ gcov_open (const char *name, int mode)
       /* pass mode (ignored) for compatibility */
       fd = open (name, O_RDONLY, S_IRUSR | S_IWUSR);
     }
-  else if (mode < 0)
+  else
      {
        /* Write mode - acquire a write-lock.  */
        s_flock.l_type = F_WRLCK;
-      fd = open (name, O_RDWR | O_CREAT | O_TRUNC, 0666);
-    }
-  else /* mode == 0 */
-    {
-      /* Read-Write mode - acquire a write-lock.  */
-      s_flock.l_type = F_WRLCK;
-      fd = open (name, O_RDWR | O_CREAT, 0666);
+       /* Truncate if force new mode.  */
+       fd = open (name, O_RDWR | O_CREAT | (mode < 0 ? O_TRUNC : 0), 0666);
     }
   if (fd < 0)
     return 0;
@@ -181,42 +175,23 @@ gcov_open (const char *name, int mode)
       close (fd);
       return 0;
     }
-
-  if (mode > 0)
-    gcov_var.mode = 1;
-  else if (mode == 0)
-    {
-      struct stat st;
-
-      if (fstat (fd, &st) < 0)
-	{
-	  fclose (gcov_var.file);
-	  gcov_var.file = 0;
-	  return 0;
-	}
-      if (st.st_size != 0)
-	gcov_var.mode = 1;
-      else
-	gcov_var.mode = mode * 2 + 1;
-    }
-  else
-    gcov_var.mode = mode * 2 + 1;
 #else
   if (mode >= 0)
+    /* Open an existing file.  */
     gcov_var.file = fopen (name, (mode > 0) ? "rb" : "r+b");
 
   if (gcov_var.file)
-    gcov_var.mode = 1;
+    mode = 1;
   else if (mode <= 0)
-    {
-      gcov_var.file = fopen (name, "w+b");
-      if (gcov_var.file)
-	gcov_var.mode = mode * 2 + 1;
-    }
+    /* Create a new file.  */
+    gcov_var.file = fopen (name, "w+b");
+
   if (!gcov_var.file)
     return 0;
 #endif
 
+  gcov_var.mode = mode ? mode : 1;
+
   setbuf (gcov_var.file, (char *)0);
 
   return 1;
@@ -372,8 +347,12 @@ gcov_write_string (const char *string)
   buffer = gcov_write_words (1 + alloc);
 
   buffer[0] = alloc;
-  buffer[alloc] = 0;
-  memcpy (&buffer[1], string, length);
+
+  if (alloc > 0)
+    {
+      buffer[alloc] = 0; /* place nul terminators.  */
+      memcpy (&buffer[1], string, length);
+    }
 }
 #endif
 
@@ -446,13 +425,11 @@ gcov_write_summary (gcov_unsigned_t tag, const struct gcov_summary *summary)
     histo_bitvector[bv_ix] = 0;
   csum = &summary->ctrs[GCOV_COUNTER_ARCS];
   for (h_ix = 0; h_ix < GCOV_HISTOGRAM_SIZE; h_ix++)
-    {
-      if (csum->histogram[h_ix].num_counters > 0)
-        {
-          histo_bitvector[h_ix / 32] |= 1 << (h_ix % 32);
-          h_cnt++;
-        }
-    }
+    if (csum->histogram[h_ix].num_counters)
+      {
+	histo_bitvector[h_ix / 32] |= 1 << (h_ix % 32);
+	h_cnt++;
+      }
   gcov_write_tag_length (tag, GCOV_TAG_SUMMARY_LENGTH (h_cnt));
   gcov_write_unsigned (summary->checksum);
   for (csum = summary->ctrs, ix = GCOV_COUNTERS_SUMMABLE; ix--; csum++)
@@ -493,7 +470,9 @@ gcov_read_words (unsigned words)
   const gcov_unsigned_t *result;
   unsigned excess = gcov_var.length - gcov_var.offset;
 
-  gcov_nonruntime_assert (gcov_var.mode > 0);
+  if (gcov_var.mode <= 0)
+    return NULL;
+
   if (excess < words)
     {
       gcov_var.start += gcov_var.offset;