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 typedef enum
  33 {
  34   JIT_NOACTION = 0,
  35   JIT_REGISTER_FN,
  36   JIT_UNREGISTER_FN
  37 } jit_actions_t;
  38
  39 struct jit_code_entry
  40 {
  41   struct jit_code_entry *next_entry;
  42   struct jit_code_entry *prev_entry;
  43   const char *symfile_addr;
  44   uint64_t symfile_size;
  45 };
  46
  47 struct jit_descriptor
  48 {
  49   uint32_t version;
  50   /* This type should be jit_actions_t, but we use uint32_t
  51      to be explicit about the bitwidth.  */
  52   uint32_t action_flag;
  53   struct jit_code_entry *relevant_entry;
  54   struct jit_code_entry *first_entry;
  55 };
  56
  57 /* GDB puts a breakpoint in this function.  */
  58 void __attribute__((noinline)) __jit_debug_register_code () { }
  59
  60 /* Make sure to specify the version statically, because the
  61    debugger may check the version before we can set it.  */
  62 struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
  63
  64 static void
  65 usage (const char *const argv0)
  66 {
  67   fprintf (stderr, "Usage: %s library [count]\n", argv0);
  68   exit (1);
  69 }
  70
  71 /* Update .p_vaddr and .sh_addr as if the code was JITted to ADDR.  */
  72
  73 static void
  74 update_locations (const void *const addr, int idx)
  75 {
  76   const ElfW (Ehdr) *const ehdr = (ElfW (Ehdr) *)addr;
  77   ElfW (Shdr) *const shdr = (ElfW (Shdr) *)((char *)addr + ehdr->e_shoff);
  78   ElfW (Phdr) *const phdr = (ElfW (Phdr) *)((char *)addr + ehdr->e_phoff);
  79   int i;
  80
  81   for (i = 0; i < ehdr->e_phnum; ++i)
  82     if (phdr[i].p_type == PT_LOAD)
  83       phdr[i].p_vaddr += (ElfW (Addr))addr;
  84
  85   for (i = 0; i < ehdr->e_shnum; ++i)
  86     {
  87       if (shdr[i].sh_type == SHT_STRTAB)
  88         {
  89           /* Note: we update both .strtab and .dynstr.  The latter would
  90              not be correct if this were a regular shared library (.hash
  91              would be wrong), but this is a simulation -- the library is
  92              never exposed to the dynamic loader, so it all ends up ok.  */
  93           char *const strtab = (char *)((ElfW (Addr))addr + shdr[i].sh_offset);
  94           char *const strtab_end = strtab + shdr[i].sh_size;
  95           char *p;
  96
  97           for (p = strtab; p < strtab_end; p += strlen (p) + 1)
  98             if (strcmp (p, "jit_function_XXXX") == 0)
  99               sprintf (p, "jit_function_%04d", idx);
 100         }
 101
 102       if (shdr[i].sh_flags & SHF_ALLOC)
 103         shdr[i].sh_addr += (ElfW (Addr))addr;
 104     }
 105 }
 106
 107 int
 108 main (int argc, char *argv[])
 109 {
 110   /* These variables are here so they can easily be set from jit.exp.  */
 111   const char *libname = NULL;
 112   int count = 0;
 113
 114   count = count;  /* gdb break here 0  */
 115
 116   if (argc < 2)
 117     usage (argv[0]);
 118   else
 119     {
 120       int i, fd;
 121       struct stat st;
 122
 123       if (libname == NULL)
 124         /* Only set if not already set from GDB.  */
 125         libname = argv[1];
 126
 127       if (argc > 2 && count == 0)
 128         /* Only set if not already set from GDB.  */
 129         count = atoi (argv[2]);
 130
 131       printf ("%s:%d: libname = %s, count = %d\n", __FILE__, __LINE__,
 132               libname, count);
 133
 134       if ((fd = open (libname, O_RDONLY)) == -1)
 135         {
 136           fprintf (stderr, "open (\"%s\", O_RDONLY): %s\n", libname,
 137                    strerror (errno));
 138           exit (1);
 139         }
 140
 141       if (fstat (fd, &st) != 0)
 142         {
 143           fprintf (stderr, "fstat (\"%d\"): %s\n", fd, strerror (errno));
 144           exit (1);
 145         }
 146
 147       for (i = 0; i < count; ++i)
 148         {
 149           const void *const addr = mmap (0, st.st_size, PROT_READ|PROT_WRITE,
 150                                          MAP_PRIVATE, fd, 0);
 151           struct jit_code_entry *const entry = calloc (1, sizeof (*entry));
 152
 153           if (addr == MAP_FAILED)
 154             {
 155               fprintf (stderr, "mmap: %s\n", strerror (errno));
 156               exit (1);
 157             }
 158
 159           update_locations (addr, i);
 160
 161           /* Link entry at the end of the list.  */
 162           entry->symfile_addr = (const char *)addr;
 163           entry->symfile_size = st.st_size;
 164           entry->prev_entry = __jit_debug_descriptor.relevant_entry;
 165           __jit_debug_descriptor.relevant_entry = entry;
 166
 167           if (entry->prev_entry != NULL)
 168             entry->prev_entry->next_entry = entry;
 169           else
 170             __jit_debug_descriptor.first_entry = entry;
 171
 172           /* Notify GDB.  */
 173           __jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
 174           __jit_debug_register_code ();
 175         }
 176
 177       i = 0;  /* gdb break here 1 */
 178
 179       /* Now unregister them all in reverse order.  */
 180       while (__jit_debug_descriptor.relevant_entry != NULL)
 181         {
 182           struct jit_code_entry *const entry =
 183             __jit_debug_descriptor.relevant_entry;
 184           struct jit_code_entry *const prev_entry = entry->prev_entry;
 185
 186           if (prev_entry != NULL)
 187             {
 188               prev_entry->next_entry = NULL;
 189               entry->prev_entry = NULL;
 190             }
 191           else
 192             __jit_debug_descriptor.first_entry = NULL;
 193
 194           /* Notify GDB.  */
 195           __jit_debug_descriptor.action_flag = JIT_UNREGISTER_FN;
 196           __jit_debug_register_code ();
 197
 198           __jit_debug_descriptor.relevant_entry = prev_entry;
 199           free (entry);
 200         }
 201     }
 202   return 0;  /* gdb break here 2  */
 203 }