According to the next code, 'pretty_name' may need additional bytes more
than 16 (may have unlimited length for array type). There is an easy way
to fix it: use 'pretty_print' for 'pretty_name'.

Let the code meet 2 white spaces alignment coding styles (originally,
some of code is 1 white sapce alignment).

It passes testsuite under fedora 20 x86_64-unknown-linux-gnu.

2014-11-22  Chen Gang  <gang.chen.5...@gmail.com>

        * ubsan.c (ubsan_type_descriptor): Use 'pretty_print' for
        'pretty_name' to avoid memory overflow
---
 gcc/ubsan.c | 57 +++++++++++++++++++++++++++------------------------------
 1 file changed, 27 insertions(+), 30 deletions(-)

diff --git a/gcc/ubsan.c b/gcc/ubsan.c
index 41cf546..c03b000 100644
--- a/gcc/ubsan.c
+++ b/gcc/ubsan.c
@@ -336,7 +336,7 @@ ubsan_type_descriptor (tree type, enum ubsan_print_style 
pstyle)
   tree dtype = ubsan_type_descriptor_type ();
   tree type2 = type;
   const char *tname = NULL;
-  char *pretty_name;
+  pretty_printer pretty_name;
   unsigned char deref_depth = 0;
   unsigned short tkind, tinfo;
 
@@ -375,54 +375,50 @@ ubsan_type_descriptor (tree type, enum ubsan_print_style 
pstyle)
     /* We weren't able to determine the type name.  */
     tname = "<unknown>";
 
-  /* Decorate the type name with '', '*', "struct", or "union".  */
-  pretty_name = (char *) alloca (strlen (tname) + 16 + deref_depth);
   if (pstyle == UBSAN_PRINT_POINTER)
     {
-      int pos = sprintf (pretty_name, "'%s%s%s%s%s%s%s",
-                        TYPE_VOLATILE (type2) ? "volatile " : "",
-                        TYPE_READONLY (type2) ? "const " : "",
-                        TYPE_RESTRICT (type2) ? "restrict " : "",
-                        TYPE_ATOMIC (type2) ? "_Atomic " : "",
-                        TREE_CODE (type2) == RECORD_TYPE
-                        ? "struct "
-                        : TREE_CODE (type2) == UNION_TYPE
-                          ? "union " : "", tname,
-                        deref_depth == 0 ? "" : " ");
+      pp_printf (&pretty_name, "'%s%s%s%s%s%s%s",
+                TYPE_VOLATILE (type2) ? "volatile " : "",
+                TYPE_READONLY (type2) ? "const " : "",
+                TYPE_RESTRICT (type2) ? "restrict " : "",
+                TYPE_ATOMIC (type2) ? "_Atomic " : "",
+                TREE_CODE (type2) == RECORD_TYPE
+                ? "struct "
+                : TREE_CODE (type2) == UNION_TYPE
+                  ? "union " : "", tname,
+                deref_depth == 0 ? "" : " ");
       while (deref_depth-- > 0)
-        pretty_name[pos++] = '*';
-      pretty_name[pos++] = '\'';
-      pretty_name[pos] = '\0';
+       pp_star(&pretty_name);
+      pp_quote(&pretty_name);
     }
   else if (pstyle == UBSAN_PRINT_ARRAY)
     {
       /* Pretty print the array dimensions.  */
       gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
       tree t = type;
-      int pos = sprintf (pretty_name, "'%s ", tname);
+      pp_printf (&pretty_name, "'%s ", tname);
       while (deref_depth-- > 0)
-        pretty_name[pos++] = '*';
+       pp_star(&pretty_name);
       while (TREE_CODE (t) == ARRAY_TYPE)
        {
-         pretty_name[pos++] = '[';
+         pp_left_bracket(&pretty_name);
          tree dom = TYPE_DOMAIN (t);
          if (dom && TREE_CODE (TYPE_MAX_VALUE (dom)) == INTEGER_CST)
-           pos += sprintf (&pretty_name[pos], HOST_WIDE_INT_PRINT_DEC,
-                           tree_to_uhwi (TYPE_MAX_VALUE (dom)) + 1);
+           pp_printf (&pretty_name, HOST_WIDE_INT_PRINT_DEC,
+                      tree_to_uhwi (TYPE_MAX_VALUE (dom)) + 1);
          else
            /* ??? We can't determine the variable name; print VLA unspec.  */
-           pretty_name[pos++] = '*';
-         pretty_name[pos++] = ']';
+           pp_star(&pretty_name);
+         pp_right_bracket(&pretty_name);
          t = TREE_TYPE (t);
        }
-      pretty_name[pos++] = '\'';
-      pretty_name[pos] = '\0';
+      pp_quote(&pretty_name);
 
-     /* Save the tree with stripped types.  */
-     type = t;
+      /* Save the tree with stripped types.  */
+      type = t;
     }
   else
-    sprintf (pretty_name, "'%s'", tname);
+    pp_printf (&pretty_name, "'%s'", tname);
 
   switch (TREE_CODE (type))
     {
@@ -459,8 +455,9 @@ ubsan_type_descriptor (tree type, enum ubsan_print_style 
pstyle)
   DECL_IGNORED_P (decl) = 1;
   DECL_EXTERNAL (decl) = 0;
 
-  size_t len = strlen (pretty_name);
-  tree str = build_string (len + 1, pretty_name);
+  const char *tmp = pp_formatted_text(&pretty_name);
+  size_t len = strlen (tmp);
+  tree str = build_string (len + 1, tmp);
   TREE_TYPE (str) = build_array_type (char_type_node,
                                      build_index_type (size_int (len)));
   TREE_READONLY (str) = 1;
-- 
1.9.3

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