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

   1 /* This test program is part of GDB, the GNU debugger.
   2
   3    Copyright 2011-2015 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 /* Simulate loading of JIT code.  */
  19
  20 #include <elf.h>
  21 #include <link.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <stdint.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/mman.h>
  29 #include <sys/stat.h>
  30
  31 /* ElfW is coming from linux. On other platforms it does not exist.
  32    Let us define it here. */
  33 #ifndef ElfW
  34 # if (defined  (_LP64) || defined (__LP64__))
  35 #   define WORDSIZE 64
  36 # else
  37 #   define WORDSIZE 32
  38 # endif /* _LP64 || __LP64__  */
  39 #define ElfW(type)      _ElfW (Elf, WORDSIZE, type)
  40 #define _ElfW(e,w,t)    _ElfW_1 (e, w, _##t)
  41 #define _ElfW_1(e,w,t)  e##w##t
  42 #endif /* !ElfW  */
  43
  44 typedef enum
  45 {
  46   JIT_NOACTION = 0,
  47   JIT_REGISTER_FN,
  48   JIT_UNREGISTER_FN
  49 } jit_actions_t;
  50
  51 struct jit_code_entry
  52 {
  53   struct jit_code_entry *next_entry;
  54   struct jit_code_entry *prev_entry;
  55   const char *symfile_addr;
  56   uint64_t symfile_size;
  57 };
  58
  59 struct jit_descriptor
  60 {
  61   uint32_t version;
  62   /* This type should be jit_actions_t, but we use uint32_t
  63      to be explicit about the bitwidth.  */
  64   uint32_t action_flag;
  65   struct jit_code_entry *relevant_entry;
  66   struct jit_code_entry *first_entry;
  67 };
  68
  69 /* GDB puts a breakpoint in this function.  */
  70 void __attribute__((noinline)) __jit_debug_register_code () { }
  71
  72 /* Make sure to specify the version statically, because the
  73    debugger may check the version before we can set it.  */
  74 struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
  75
  76 static void
  77 usage (const char *const argv0)
  78 {
  79   fprintf (stderr, "Usage: %s library [count]\n", argv0);
  80   exit (1);
  81 }
  82
  83 /* Update .p_vaddr and .sh_addr as if the code was JITted to ADDR.  */
  84
  85 static void
  86 update_locations (const void *const addr, int idx)
  87 {
  88   const ElfW (Ehdr) *const ehdr = (ElfW (Ehdr) *)addr;
  89   ElfW (Shdr) *const shdr = (ElfW (Shdr) *)((char *)addr + ehdr->e_shoff);
  90   ElfW (Phdr) *const phdr = (ElfW (Phdr) *)((char *)addr + ehdr->e_phoff);
  91   int i;
  92
  93   for (i = 0; i < ehdr->e_phnum; ++i)
  94     if (phdr[i].p_type == PT_LOAD)
  95       phdr[i].p_vaddr += (ElfW (Addr))addr;
  96
  97   for (i = 0; i < ehdr->e_shnum; ++i)
  98     {
  99       if (shdr[i].sh_type == SHT_STRTAB)
 100         {
 101           /* Note: we update both .strtab and .dynstr.  The latter would
 102              not be correct if this were a regular shared library (.hash
 103              would be wrong), but this is a simulation -- the library is
 104              never exposed to the dynamic loader, so it all ends up ok.  */
 105           char *const strtab = (char *)((ElfW (Addr))addr + shdr[i].sh_offset);
 106           char *const strtab_end = strtab + shdr[i].sh_size;
 107           char *p;
 108
 109           for (p = strtab; p < strtab_end; p += strlen (p) + 1)
 110             if (strcmp (p, "jit_function_XXXX") == 0)
 111               sprintf (p, "jit_function_%04d", idx);
 112         }
 113
 114       if (shdr[i].sh_flags & SHF_ALLOC)
 115         shdr[i].sh_addr += (ElfW (Addr))addr;
 116     }
 117 }
 118
 119 #ifndef MAIN
 120 #define MAIN main
 121 #endif
 122
 123 int
 124 MAIN (int argc, char *argv[])
 125 {
 126   /* These variables are here so they can easily be set from jit.exp.  */
 127   const char *libname = NULL;
 128   int count = 0;
 129
 130   count = count;  /* gdb break here 0  */
 131
 132   if (argc < 2)
 133     usage (argv[0]);
 134   else
 135     {
 136       int i, fd;
 137       struct stat st;
 138
 139       if (libname == NULL)
 140         /* Only set if not already set from GDB.  */
 141         libname = argv[1];
 142
 143       if (argc > 2 && count == 0)
 144         /* Only set if not already set from GDB.  */
 145         count = atoi (argv[2]);
 146
 147       printf ("%s:%d: libname = %s, count = %d\n", __FILE__, __LINE__,
 148               libname, count);
 149
 150       if ((fd = open (libname, O_RDONLY)) == -1)
 151         {
 152           fprintf (stderr, "open (\"%s\", O_RDONLY): %s\n", libname,
 153                    strerror (errno));
 154           exit (1);
 155         }
 156
 157       if (fstat (fd, &st) != 0)
 158         {
 159           fprintf (stderr, "fstat (\"%d\"): %s\n", fd, strerror (errno));
 160           exit (1);
 161         }
 162
 163       for (i = 0; i < count; ++i)
 164         {
 165           const void *const addr = mmap (0, st.st_size, PROT_READ|PROT_WRITE,
 166                                          MAP_PRIVATE, fd, 0);
 167           struct jit_code_entry *const entry = calloc (1, sizeof (*entry));
 168
 169           if (addr == MAP_FAILED)
 170             {
 171               fprintf (stderr, "mmap: %s\n", strerror (errno));
 172               exit (1);
 173             }
 174
 175           update_locations (addr, i);
 176
 177           /* Link entry at the end of the list.  */
 178           entry->symfile_addr = (const char *)addr;
 179           entry->symfile_size = st.st_size;
 180           entry->prev_entry = __jit_debug_descriptor.relevant_entry;
 181           __jit_debug_descriptor.relevant_entry = entry;
 182
 183           if (entry->prev_entry != NULL)
 184             entry->prev_entry->next_entry = entry;
 185           else
 186             __jit_debug_descriptor.first_entry = entry;
 187
 188           /* Notify GDB.  */
 189           __jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
 190           __jit_debug_register_code ();
 191         }
 192
 193       i = 0;  /* gdb break here 1 */
 194
 195       /* Now unregister them all in reverse order.  */
 196       while (__jit_debug_descriptor.relevant_entry != NULL)
 197         {
 198           struct jit_code_entry *const entry =
 199             __jit_debug_descriptor.relevant_entry;
 200           struct jit_code_entry *const prev_entry = entry->prev_entry;
 201
 202           if (prev_entry != NULL)
 203             {
 204               prev_entry->next_entry = NULL;
 205               entry->prev_entry = NULL;
 206             }
 207           else
 208             __jit_debug_descriptor.first_entry = NULL;
 209
 210           /* Notify GDB.  */
 211           __jit_debug_descriptor.action_flag = JIT_UNREGISTER_FN;
 212           __jit_debug_register_code ();
 213
 214           __jit_debug_descriptor.relevant_entry = prev_entry;
 215           free (entry);
 216         }
 217     }
 218   return 0;  /* gdb break here 2  */
 219 }