[google] Fix parallel make issue exposed by recent gcda change (issue7426043)

Index: gcc/coverage.c
===================================================================
--- gcc/coverage.c	(revision 196314)
+++ gcc/coverage.c	(working copy)
@@ -1961,12 +1961,6 @@  build_info_type (tree type, tree fn_info_ptr_type)
   DECL_CHAIN (field) = fields;
   fields = field;
 
-  /* eof_pos */
-  field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
-                      NULL_TREE, get_gcov_unsigned_t ());
-  DECL_CHAIN (field) = fields;
-  fields = field;
-
   /* merge fn array */
   merge_fn_type
     = build_function_type_list (void_type_node,
@@ -2412,11 +2406,6 @@  build_info (tree info_type, tree fn_ary)
 				  filename_string));
   info_fields = DECL_CHAIN (info_fields);
 
-  /* eof_pos */
-  CONSTRUCTOR_APPEND_ELT (v1, info_fields,
-                          build_int_cstu (TREE_TYPE (info_fields), 0));
-  info_fields = DECL_CHAIN (info_fields);
-
   /* merge fn array -- NULL slots indicate unmeasured counters */
   merge_fn_type = TREE_TYPE (TREE_TYPE (info_fields));
   for (ix = 0; ix != GCOV_COUNTERS; ix++)
Index: gcc/gcov-io.c
===================================================================
--- gcc/gcov-io.c	(revision 196314)
+++ gcc/gcov-io.c	(working copy)
@@ -824,6 +824,19 @@  gcov_seek (gcov_position_t base)
   gcov_var.start = _GCOV_ftell (gcov_var.file) >> 2;
 }
 
+/* Move to the end minus the given number of 4-byte words.  */
+
+GCOV_LINKAGE void
+gcov_seek_from_end (gcov_position_t offset)
+{
+  int offset_in_bytes = offset << 2;
+  gcc_assert (gcov_var.mode < 0);
+  if (gcov_var.offset)
+    gcov_write_block (gcov_var.offset);
+  _GCOV_fseek (gcov_var.file, -offset_in_bytes, SEEK_END);
+  gcov_var.start = _GCOV_ftell (gcov_var.file) >> 2;
+}
+
 /* Truncate the gcov file at the current position.  */
 
 GCOV_LINKAGE void
Index: gcc/gcov-io.h
===================================================================
--- gcc/gcov-io.h	(revision 196314)
+++ gcc/gcov-io.h	(working copy)
@@ -391,6 +391,7 @@  typedef unsigned HOST_WIDEST_INT gcov_type_unsigne
 #define gcov_write_tag_length __gcov_write_tag_length
 #define gcov_position __gcov_position
 #define gcov_seek __gcov_seek
+#define gcov_seek_from_end __gcov_seek_from_end
 #define gcov_rewrite __gcov_rewrite
 #define gcov_truncate __gcov_truncate
 #define gcov_is_error __gcov_is_error
@@ -802,7 +803,6 @@  struct gcov_info
 
   gcov_unsigned_t stamp;	/* uniquifying time stamp */
   const char *filename;		/* output file name */
-  gcov_unsigned_t eof_pos;      /* end position of profile data */
   gcov_merge_fn merge[GCOV_COUNTERS];  /* merge functions (null for
 					  unused) */
   
@@ -925,10 +925,10 @@  extern struct gcov_var gcov_var;
    file either for reading or for writing. When reading a file you may
    use the gcov_read_* functions, gcov_sync, gcov_position, &
    gcov_error. When writing a file you may use the gcov_write
-   functions, gcov_seek & gcov_error. When a file is to be rewritten
-   you use the functions for reading, then gcov_rewrite then the
-   functions for writing.  Your file may become corrupted if you break
-   these invariants.  */
+   functions, gcov_seek, gcov_seek_from_end & gcov_error. When a file
+   is to be rewritten you use the functions for reading, then gcov_rewrite
+   then the functions for writing.  Your file may become corrupted if you
+   break these invariants.  */
 #if IN_LIBGCOV
 GCOV_LINKAGE int gcov_open (const char */*name*/) ATTRIBUTE_HIDDEN;
 #else
@@ -1012,6 +1012,8 @@  gcov_get_sorted_import_module_array (struct gcov_i
     ATTRIBUTE_HIDDEN;
 static void gcov_rewrite (void);
 GCOV_LINKAGE void gcov_seek (gcov_position_t /*position*/) ATTRIBUTE_HIDDEN;
+GCOV_LINKAGE void gcov_seek_from_end (gcov_position_t /*offset*/)
+    ATTRIBUTE_HIDDEN;
 GCOV_LINKAGE void gcov_truncate (void) ATTRIBUTE_HIDDEN;
 GCOV_LINKAGE gcov_unsigned_t gcov_string_length (const char *) ATTRIBUTE_HIDDEN;
 GCOV_LINKAGE unsigned gcov_gcda_file_size (struct gcov_info *);
Index: libgcc/libgcov.c
===================================================================
--- libgcc/libgcov.c	(revision 196314)
+++ libgcc/libgcov.c	(working copy)
@@ -226,9 +226,6 @@  static struct gcov_summary program;
 /* Record the position of summary info.  */
 static gcov_position_t summary_pos = 0;
 
-/* Record the postion of eof.  */
-static gcov_position_t eof_pos = 0;
-
 /* Number of chars in prefix to be stripped.  */
 static int gcov_prefix_strip = 0;
 
@@ -580,7 +577,7 @@  gcov_dump_module_info (int do_lipo)
 
     /* Overwrite the zero word at the of the file.  */
     gcov_rewrite ();
-    gcov_seek (gi_ptr->eof_pos);
+    gcov_seek_from_end (1);
 
     gcov_write_module_infos (gi_ptr, do_lipo);
     /* Write the end marker  */
@@ -947,8 +944,8 @@  gcov_merge_gcda_file (struct gcov_info *gi_ptr)
   const struct gcov_fn_info *gfi_ptr;
   int error = 0;
   gcov_unsigned_t tag, length, version, stamp;
+  gcov_position_t eof_pos = 0;
 
-  eof_pos = 0;
   summary_pos = 0;
   sum_buffer = 0;
   sum_tail = &sum_buffer;
@@ -1202,7 +1199,6 @@  gcov_write_gcda_file (struct gcov_info *gi_ptr)
   const struct gcov_ctr_info *ci_ptr;
   unsigned t_ix, f_ix, n_counts, length;
   int error = 0;
-  gcov_position_t eof_pos1 = 0;
 
   /* Write out the data.  */
   gcov_seek (0);
@@ -1259,14 +1255,10 @@  gcov_write_gcda_file (struct gcov_info *gi_ptr)
             gcov_write_counter (*c_ptr++);
           ci_ptr++;
         }
-      eof_pos1 = gcov_position ();
     }
-    eof_pos = eof_pos1;
     /* Write the end marker  */
     gcov_write_unsigned (0);
 
-    gi_ptr->eof_pos = eof_pos;
-
     if ((error = gcov_close ()))
       gcov_error (error  < 0 ?
                   "profiling:%s:Overflow writing\n" :