[PATCH] Fix massive memory leak in read_line (PR middle-end/53510)

[Jakub Jelinek]

Hi!

As soon as line length goes over 200 bytes, read_line starts leaking
memory (for line length x where x > 200 bytes it leaks
((1UL << ((x - 199) / 2)) - 1) * 200 bytes).

This patch fixes it.  As noted by Manuel, he copied that buggy code
from gcov.c, so this fixes gcov too.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2012-05-29  Jakub Jelinek  <ja...@redhat.com>

        PR middle-end/53510
        * input.c (read_line): Use XRESIZEVEC instead of XNEWVEC
        to avoid leaking memory.  No need to handle memory allocation
        failure.  Double string_len on each reallocation instead of
        adding 2.
        * gcov.c (read_line): Likewise.

--- gcc/input.c.jj      2012-05-02 09:38:42.000000000 +0200
+++ gcc/input.c 2012-05-29 09:22:05.123856883 +0200
@@ -105,15 +105,8 @@ read_line (FILE *file)
          return string;
        }
       pos += len;
-      ptr = XNEWVEC (char, string_len * 2);
-      if (ptr)
-       {
-         memcpy (ptr, string, pos);
-         string = ptr;
-         string_len += 2;
-       }
-      else
-       pos = 0;
+      string = XRESIZEVEC (char, string, string_len * 2);
+      string_len *= 2;
     }
       
   return pos ? string : NULL;
--- gcc/gcov.c.jj       2012-01-13 21:47:35.719634891 +0100
+++ gcc/gcov.c  2012-05-29 10:30:21.862814065 +0200
@@ -2219,15 +2219,8 @@ read_line (FILE *file)
          return string;
        }
       pos += len;
-      ptr = XNEWVEC (char, string_len * 2);
-      if (ptr)
-       {
-         memcpy (ptr, string, pos);
-         string = ptr;
-         string_len += 2;
-       }
-      else
-       pos = 0;
+      string = XRESIZEVEC (char, string, string_len * 2);
+      string_len *= 2;
     }
       
   return pos ? string : NULL;

        Jakub