The Tor Browser / file diff

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/xpcom/reflect/xptcall/src/md/unix/vtable_layout_x86.cpp	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,66 @@
     1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
     1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
     1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
     1.7 +
     1.8 +/* this code contributed by Bert Driehuis <bert_driehuis@nl.compuware.com> */
     1.9 +
    1.10 +#include <stdio.h>
    1.11 +
    1.12 +// Try to determine the vtable layout generated by G++
    1.13 +// Produces the offset at which the first vtable entry can be
    1.14 +// found, and the factor to apply for subsequent entries on stdout.
    1.15 +// Example output:
    1.16 +//    #define GCC_VTABLE_START        0xc
    1.17 +//    #define GCC_VTABLE_FACTOR       0x8
    1.18 +
    1.19 +class test {
    1.20 +public:
    1.21 +      virtual int     t1(void);
    1.22 +      virtual int     t2(void);
    1.23 +      int             x;
    1.24 +};
    1.25 +
    1.26 +test::test() { this->x = 0x12121212; };
    1.27 +
    1.28 +int test::t1(void) { return 1; }
    1.29 +int test::t2(void) { return 2; }
    1.30 +
    1.31 +void die(char *x) {
    1.32 +      fprintf(stderr, "%s\n", x);
    1.33 +      exit(1);
    1.34 +}
    1.35 +
    1.36 +int 
    1.37 +main()
    1.38 +{
    1.39 +      int             i;
    1.40 +      test           *t = new test();
    1.41 +      int            *tp = (int *) t;
    1.42 +      int             off1 = -1;
    1.43 +      int             off2 = -1;
    1.44 +      int             factor;
    1.45 +      int             factorshift;
    1.46 +
    1.47 +      if (*tp++ != 0x12121212)
    1.48 +              die("Integer element test::x not found!");
    1.49 +      tp = (int *) *tp;
    1.50 +      for (i = 0; i < 10; i++) {
    1.51 +              if (tp[i] == (int) t->t1)
    1.52 +                      off1 = i;
    1.53 +              if (tp[i] == (int) t->t2)
    1.54 +                      off2 = i;
    1.55 +      }
    1.56 +      if (off1 == -1 || off2 == -1)
    1.57 +              die("Could not determine offset into vtable!");
    1.58 +      factor = (off2 - off1) * 4;
    1.59 +      factorshift = -1;
    1.60 +      while (factor) {
    1.61 +              factorshift++;
    1.62 +              factor >>= 1;
    1.63 +      }
    1.64 +      printf("/* Automatically generated by vtable_layout_x86.cpp */\n");
    1.65 +      printf("#define GCC_VTABLE_START\t0x%x\n", off1 * 4);
    1.66 +      printf("#define GCC_VTABLE_FACTOR\t0x%x\n", (off2 - off1) * 4);
    1.67 +      printf("#define GCC_VTABLE_SHIFT\t0x%x\n", factorshift);
    1.68 +      exit(0);
    1.69 +}