gdb/testsuite/gdb.base/jit-main.c

   1 /* This test program is part of GDB, the GNU debugger.
   2
   3    Copyright 2011 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17    */
  18
  19 /* Simulate loading of JIT code.  */
  20
  21 #include <elf.h>
  22 #include <link.h>
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <stdint.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31
  32 /* ElfW is coming from linux. On other platforms it does not exist.
  33    Let us define it here. */
  34 #ifndef ElfW
  35 # if (defined  (_LP64) || defined (__LP64__))
  36 #   define WORDSIZE 64
  37 # else
  38 #   define WORDSIZE 32
  39 # endif /* _LP64 || __LP64__  */
  40 #define ElfW(type)      _ElfW (Elf, WORDSIZE, type)
  41 #define _ElfW(e,w,t)    _ElfW_1 (e, w, _##t)
  42 #define _ElfW_1(e,w,t)  e##w##t
  43 #endif /* !ElfW  */
  44
  45 typedef enum
  46 {
  47   JIT_NOACTION = 0,
  48   JIT_REGISTER_FN,
  49   JIT_UNREGISTER_FN
  50 } jit_actions_t;
  51
  52 struct jit_code_entry
  53 {
  54   struct jit_code_entry *next_entry;
  55   struct jit_code_entry *prev_entry;
  56   const char *symfile_addr;
  57   uint64_t symfile_size;
  58 };
  59
  60 struct jit_descriptor
  61 {
  62   uint32_t version;
  63   /* This type should be jit_actions_t, but we use uint32_t
  64      to be explicit about the bitwidth.  */
  65   uint32_t action_flag;
  66   struct jit_code_entry *relevant_entry;
  67   struct jit_code_entry *first_entry;
  68 };
  69
  70 /* GDB puts a breakpoint in this function.  */
  71 void __attribute__((noinline)) __jit_debug_register_code () { }
  72
  73 /* Make sure to specify the version statically, because the
  74    debugger may check the version before we can set it.  */
  75 struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
  76
  77 static void
  78 usage (const char *const argv0)
  79 {
  80   fprintf (stderr, "Usage: %s library [count]\n", argv0);
  81   exit (1);
  82 }
  83
  84 /* Update .p_vaddr and .sh_addr as if the code was JITted to ADDR.  */
  85
  86 static void
  87 update_locations (const void *const addr, int idx)
  88 {
  89   const ElfW (Ehdr) *const ehdr = (ElfW (Ehdr) *)addr;
  90   ElfW (Shdr) *const shdr = (ElfW (Shdr) *)((char *)addr + ehdr->e_shoff);
  91   ElfW (Phdr) *const phdr = (ElfW (Phdr) *)((char *)addr + ehdr->e_phoff);
  92   int i;
  93
  94   for (i = 0; i < ehdr->e_phnum; ++i)
  95     if (phdr[i].p_type == PT_LOAD)
  96       phdr[i].p_vaddr += (ElfW (Addr))addr;
  97
  98   for (i = 0; i < ehdr->e_shnum; ++i)
  99     {
 100       if (shdr[i].sh_type == SHT_STRTAB)
 101         {
 102           /* Note: we update both .strtab and .dynstr.  The latter would
 103              not be correct if this were a regular shared library (.hash
 104              would be wrong), but this is a simulation -- the library is
 105              never exposed to the dynamic loader, so it all ends up ok.  */
 106           char *const strtab = (char *)((ElfW (Addr))addr + shdr[i].sh_offset);
 107           char *const strtab_end = strtab + shdr[i].sh_size;
 108           char *p;
 109
 110           for (p = strtab; p < strtab_end; p += strlen (p) + 1)
 111             if (strcmp (p, "jit_function_XXXX") == 0)
 112               sprintf (p, "jit_function_%04d", idx);
 113         }
 114
 115       if (shdr[i].sh_flags & SHF_ALLOC)
 116         shdr[i].sh_addr += (ElfW (Addr))addr;
 117     }
 118 }
 119
 120 #ifndef MAIN
 121 #define MAIN main
 122 #endif
 123
 124 int
 125 MAIN (int argc, char *argv[])
 126 {
 127   /* These variables are here so they can easily be set from jit.exp.  */
 128   const char *libname = NULL;
 129   int count = 0;
 130
 131   count = count;  /* gdb break here 0  */
 132
 133   if (argc < 2)
 134     usage (argv[0]);
 135   else
 136     {
 137       int i, fd;
 138       struct stat st;
 139
 140       if (libname == NULL)
 141         /* Only set if not already set from GDB.  */
 142         libname = argv[1];
 143
 144       if (argc > 2 && count == 0)
 145         /* Only set if not already set from GDB.  */
 146         count = atoi (argv[2]);
 147
 148       printf ("%s:%d: libname = %s, count = %d\n", __FILE__, __LINE__,
 149               libname, count);
 150
 151       if ((fd = open (libname, O_RDONLY)) == -1)
 152         {
 153           fprintf (stderr, "open (\"%s\", O_RDONLY): %s\n", libname,
 154                    strerror (errno));
 155           exit (1);
 156         }
 157
 158       if (fstat (fd, &st) != 0)
 159         {
 160           fprintf (stderr, "fstat (\"%d\"): %s\n", fd, strerror (errno));
 161           exit (1);
 162         }
 163
 164       for (i = 0; i < count; ++i)
 165         {
 166           const void *const addr = mmap (0, st.st_size, PROT_READ|PROT_WRITE,
 167                                          MAP_PRIVATE, fd, 0);
 168           struct jit_code_entry *const entry = calloc (1, sizeof (*entry));
 169
 170           if (addr == MAP_FAILED)
 171             {
 172               fprintf (stderr, "mmap: %s\n", strerror (errno));
 173               exit (1);
 174             }
 175
 176           update_locations (addr, i);
 177
 178           /* Link entry at the end of the list.  */
 179           entry->symfile_addr = (const char *)addr;
 180           entry->symfile_size = st.st_size;
 181           entry->prev_entry = __jit_debug_descriptor.relevant_entry;
 182           __jit_debug_descriptor.relevant_entry = entry;
 183
 184           if (entry->prev_entry != NULL)
 185             entry->prev_entry->next_entry = entry;
 186           else
 187             __jit_debug_descriptor.first_entry = entry;
 188
 189           /* Notify GDB.  */
 190           __jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
 191           __jit_debug_register_code ();
 192         }
 193
 194       i = 0;  /* gdb break here 1 */
 195
 196       /* Now unregister them all in reverse order.  */
 197       while (__jit_debug_descriptor.relevant_entry != NULL)
 198         {
 199           struct jit_code_entry *const entry =
 200             __jit_debug_descriptor.relevant_entry;
 201           struct jit_code_entry *const prev_entry = entry->prev_entry;
 202
 203           if (prev_entry != NULL)
 204             {
 205               prev_entry->next_entry = NULL;
 206               entry->prev_entry = NULL;
 207             }
 208           else
 209             __jit_debug_descriptor.first_entry = NULL;
 210
 211           /* Notify GDB.  */
 212           __jit_debug_descriptor.action_flag = JIT_UNREGISTER_FN;
 213           __jit_debug_register_code ();
 214
 215           __jit_debug_descriptor.relevant_entry = prev_entry;
 216           free (entry);
 217         }
 218     }
 219   return 0;  /* gdb break here 2  */
 220 }