gdb/testsuite/gdb.arch/thumb-prologue.c

   1 /* Unwinder test program.
   2
   3    Copyright 2006, 2007 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 void tpcs_frame (void);
  21
  22 int
  23 main (void)
  24 {
  25   tpcs_frame ();
  26   return 0;
  27 }
  28
  29 /* Normally Thumb functions use r7 as the frame pointer.  However,
  30    with the GCC option -mtpcs-frame, they may use fp instead.  Make
  31    sure that the prologue analyzer can handle this.  */
  32
  33 asm(".text\n"
  34     "   .align 2\n"
  35     "   .thumb_func\n"
  36     "   .code 16\n"
  37     "tpcs_frame_1:\n"
  38     "   sub     sp, #16\n"
  39     "   push    {r7}\n"
  40     "   add     r7, sp, #20\n"
  41     "   str     r7, [sp, #8]\n"
  42     "   mov     r7, pc\n"
  43     "   str     r7, [sp, #16]\n"
  44     "   mov     r7, fp\n"
  45     "   str     r7, [sp, #4]\n"
  46     "   mov     r7, lr\n"
  47     "   str     r7, [sp, #12]\n"
  48     "   add     r7, sp, #16\n"
  49     "   mov     fp, r7\n"
  50     "   mov     r7, sl\n"
  51     "   push    {r7}\n"
  52
  53     /* We'll set a breakpoint at this call.  We can't hardcode a trap
  54        instruction; the right instruction to use varies too much.  And
  55        we can't use a global label, because GDB will think that's the
  56        start of a new function.  So, this slightly convoluted
  57        technique.  */
  58     ".Ltpcs:\n"
  59     "   nop\n"
  60
  61     "   pop     {r2}\n"
  62     "   mov     sl, r2\n"
  63     "   pop     {r7}\n"
  64     "   pop     {r1, r2}\n"
  65     "   mov     fp, r1\n"
  66     "   mov     sp, r2\n"
  67     "   bx      lr\n"
  68
  69     "   .align 2\n"
  70     "   .type tpcs_offset, %object\n"
  71     "tpcs_offset:\n"
  72     "   .word .Ltpcs - tpcs_frame_1\n"
  73
  74     "   .align 2\n"
  75     "   .thumb_func\n"
  76     "   .code 16\n"
  77     "tpcs_frame:\n"
  78     "   sub     sp, #16\n"
  79     "   push    {r7}\n"
  80     "   add     r7, sp, #20\n"
  81     "   str     r7, [sp, #8]\n"
  82     "   mov     r7, pc\n"
  83     "   str     r7, [sp, #16]\n"
  84     "   mov     r7, fp\n"
  85     "   str     r7, [sp, #4]\n"
  86     "   mov     r7, lr\n"
  87     "   str     r7, [sp, #12]\n"
  88     "   add     r7, sp, #16\n"
  89     "   mov     fp, r7\n"
  90     "   mov     r7, sl\n"
  91     "   push    {r7}\n"
  92
  93     /* Clobber saved regs around the call.  */
  94     "   mov     r7, #0\n"
  95     "   mov     lr, r7\n"
  96     "   bl      tpcs_frame_1\n"
  97
  98     "   pop     {r2}\n"
  99     "   mov     sl, r2\n"
 100     "   pop     {r7}\n"
 101     "   pop     {r1, r2, r3}\n"
 102     "   mov     fp, r1\n"
 103     "   mov     sp, r2\n"
 104     "   mov     lr, r3\n"
 105     "   bx      lr\n"
 106 );