Add support for separate debug files, which are just separate ELF files

containing the relevant debug sections and located using the information
in the .gnu_debuglink section of the main file along with some search
rules and checksum logic borrowed from binutils/gdb.

CCMAIL: 82872-done@bugs.kde.org

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@2408

diff --git a/coregrind/vg_symtab2.c b/coregrind/vg_symtab2.c
index 3278d9ad63a129f7f6148d0187695905f59a36bd..d62872e202c4d72c9c32de72610f930db56f7bdf 100644 (file)
--- a/coregrind/vg_symtab2.c
+++ b/coregrind/vg_symtab2.c
@@ -1003,6 +1003,144 @@ void read_symtab( SegInfo* si, Char* tab_name, Bool do_intercepts,
    }
 }
 
+/*
+ * This routine for calculating the CRC for a separate debug file
+ * is GPLed code borrowed from binutils.
+ */
+static UInt
+calc_gnu_debuglink_crc32(UInt crc, const UChar *buf, Int len)
+{
+  static const UInt crc32_table[256] =
+    {
+      0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
+      0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
+      0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
+      0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+      0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
+      0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+      0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
+      0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+      0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
+      0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
+      0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
+      0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+      0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
+      0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
+      0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
+      0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+      0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
+      0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+      0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
+      0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+      0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
+      0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
+      0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
+      0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+      0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
+      0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
+      0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
+      0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+      0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
+      0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+      0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
+      0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+      0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
+      0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
+      0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
+      0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+      0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
+      0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
+      0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
+      0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+      0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
+      0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+      0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
+      0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+      0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
+      0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
+      0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
+      0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+      0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
+      0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
+      0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
+      0x2d02ef8d
+    };
+  const UChar *end;
+
+  crc = ~crc & 0xffffffff;
+  for (end = buf + len; buf < end; ++ buf)
+    crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8);
+  return ~crc & 0xffffffff;;
+}
+
+/*
+ * Try and open a separate debug file, ignoring any where the CRC does
+ * not match the value from the main object file.
+ */
+static
+Addr open_debug_file( Char* name, UInt crc, UInt* size )
+{
+   Int fd;
+   struct vki_stat stat_buf;
+   Addr addr;
+
+   if ((fd = VG_(open)(name, VKI_O_RDONLY, 0)) < 0)
+      return 0;
+
+   if (VG_(fstat)(fd, &stat_buf) != 0) {
+      VG_(close)(fd);
+      return 0;
+   }
+
+   *size = stat_buf.st_size;
+   
+   if ((addr = (Addr)VG_(mmap)(NULL, *size, VKI_PROT_READ,
+                               VKI_MAP_PRIVATE|VKI_MAP_NOSYMS, fd, 0)) == (Addr)-1) {
+      VG_(close)(fd);
+      return 0;
+   }
+
+   VG_(close)(fd);
+   
+   if (calc_gnu_debuglink_crc32(0, (UChar*)addr, *size) != crc) {
+      VG_(munmap)((void*)addr, *size);
+      return 0;
+   }
+   
+   return addr;
+}
+
+/*
+ * Try and find a seperated debug file for a given object file.
+ */
+static
+Addr find_debug_file( Char* objpath, Char* debugname, UInt crc, UInt* size )
+{
+   Char *objdir = VG_(strdup)(objpath);
+   Char *objdirptr;
+   Char *debugpath;
+   Addr addr = 0;
+  
+   if ((objdirptr = VG_(strrchr)(objdir, '/')) != NULL)
+      *objdirptr = '\0';
+
+   debugpath = VG_(malloc)(VG_(strlen)(objdir) + VG_(strlen)(debugname) + 16);
+   
+   VG_(sprintf)(debugpath, "%s/%s", objdir, debugname);
+
+   if ((addr = open_debug_file(debugpath, crc, size)) == 0) {
+      VG_(sprintf)(debugpath, "%s/.debug/%s", objdir, debugname);
+      if ((addr = open_debug_file(debugpath, crc, size)) == 0) {
+         VG_(sprintf)(debugpath, "/usr/lib/debug%s/%s", objdir, debugname);
+         addr = open_debug_file(debugpath, crc, size);
+      }
+   }
+
+   VG_(free)(debugpath);
+   VG_(free)(objdir);
+   
+   return addr;
+}
 
 /* Read the symbols from the object/exe specified by the SegInfo into
    the tables within the supplied SegInfo.  */
@@ -1018,6 +1156,8 @@ Bool vg_read_lib_symbols ( SegInfo* si )
    Bool          ok;
    Addr          oimage;
    UInt          n_oimage;
+   Addr          dimage = 0;
+   UInt          n_dimage = 0;
    struct vki_stat stat_buf;
 
    oimage = (Addr)NULL;
@@ -1199,6 +1339,7 @@ Bool vg_read_lib_symbols ( SegInfo* si )
       Elf32_Sym* o_symtab     = NULL; /* .symtab */
       UChar*     o_dynstr     = NULL; /* .dynstr */
       Elf32_Sym* o_dynsym     = NULL; /* .dynsym */
+      Char*      debuglink    = NULL; /* .gnu_debuglink */
       UChar*     stab         = NULL; /* .stab         (stabs)  */
       UChar*     stabstr      = NULL; /* .stabstr      (stabs)  */
       UChar*     debug_line   = NULL; /* .debug_line   (dwarf2) */
@@ -1210,6 +1351,7 @@ Bool vg_read_lib_symbols ( SegInfo* si )
       UInt       o_symtab_sz     = 0;
       UInt       o_dynstr_sz     = 0;
       UInt       o_dynsym_sz     = 0;
+      UInt       debuglink_sz    = 0;
       UInt       stab_sz         = 0;
       UInt       stabstr_sz      = 0;
       UInt       debug_line_sz   = 0;
@@ -1244,6 +1386,8 @@ Bool vg_read_lib_symbols ( SegInfo* si )
          else FIND(".symtab",       o_symtab,     o_symtab_sz,   0, Elf32_Sym*)
          else FIND(".strtab",       o_strtab,     o_strtab_sz,   0, UChar*)
 
+         else FIND(".gnu_debuglink", debuglink,   debuglink_sz,  0, Char*)
+
          else FIND(".stab",         stab,         stab_sz,       0, UChar*)
          else FIND(".stabstr",      stabstr,      stabstr_sz,    0, UChar*)
          else FIND(".debug_line",   debug_line,   debug_line_sz, 0, UChar*)
@@ -1268,6 +1412,59 @@ Bool vg_read_lib_symbols ( SegInfo* si )
                   o_dynsym, o_dynsym_sz,
                   o_dynstr, o_dynstr_sz);
 
+      /* Did we find a debuglink section? */
+      if (debuglink != NULL) {
+         UInt crc_offset = (VG_(strlen)(debuglink) + 4) & ~3;
+         UInt crc;
+
+         vg_assert(crc_offset + sizeof(UInt) <= debuglink_sz);
+
+         /* Extract the CRC from the debuglink section */
+         crc = *(UInt *)(debuglink + crc_offset);
+
+         /* See if we can find a matching debug file */
+         if ((dimage = find_debug_file(si->filename, debuglink, crc, &n_dimage)) != 0) {
+            ehdr = (Elf32_Ehdr*)dimage;
+
+            if (n_dimage >= sizeof(Elf32_Ehdr) && VG_(is_object_file)(ehdr))
+            {
+               shdr = (Elf32_Shdr*)(dimage + ehdr->e_shoff);
+               sh_strtab = (UChar*)(dimage + shdr[ehdr->e_shstrndx].sh_offset);
+
+               /* Find all interesting sections */
+               for (i = 0; i < ehdr->e_shnum; i++) {
+#                 define FIND(sec_name, sec_data, sec_size, type) \
+                  if (0 == VG_(strcmp)(sec_name, sh_strtab + shdr[i].sh_name)) { \
+                     if (0 != sec_data) \
+                        VG_(core_panic)("repeated section!\n"); \
+                     sec_data = (type)(dimage + shdr[i].sh_offset); \
+                     sec_size = shdr[i].sh_size; \
+                     TRACE_SYMTAB( "%18s: %p .. %p\n", \
+                                   sec_name, sec_data, sec_data + sec_size - 1); \
+                     if ( shdr[i].sh_offset + sec_size > n_dimage ) { \
+                        VG_(symerr)("   section beyond image end?!"); \
+                        goto out; \
+                     } \
+                  }
+
+                  /* Nb: must find where .got and .plt sections will be in the
+                   * executable image, not in the object image transiently loaded. */
+                       FIND(".stab",         stab,         stab_sz,       UChar*)
+                  else FIND(".stabstr",      stabstr,      stabstr_sz,    UChar*)
+                  else FIND(".debug_line",   debug_line,   debug_line_sz, UChar*)
+                  else FIND(".debug",        dwarf1d,      dwarf1d_sz,    UChar*)
+                  else FIND(".line",         dwarf1l,      dwarf1l_sz,    UChar*)
+
+#                 undef FIND
+         
+                  /* Check some sizes */
+                  vg_assert((o_dynsym_sz % sizeof(Elf32_Sym)) == 0);
+                  vg_assert((o_symtab_sz % sizeof(Elf32_Sym)) == 0);
+               }
+            }
+         }
+      }
+
       /* Read the stabs and/or dwarf2 debug information, if any. */
       if (stab != NULL && stabstr != NULL) {
          has_debuginfo = True;
@@ -1291,7 +1488,8 @@ Bool vg_read_lib_symbols ( SegInfo* si )
    res = True;
 
   out:
-   /* Last, but not least, heave the oimage back overboard. */
+   /* Last, but not least, heave the image(s) back overboard. */
+   if (dimage) VG_(munmap) ( (void*)dimage, n_dimage );
    VG_(munmap) ( (void*)oimage, n_oimage );
    return res;
 }