tools/jprof/elf.cpp

   1 /* ***** BEGIN LICENSE BLOCK *****
   2  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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  14  * The Original Code is mozilla.org code.
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  16  * The Initial Developer of the Original Code is Netscape Communications Corp.
  17  * Portions created by the Initial Developer are Copyright (C) 1998
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  22  * Alternatively, the contents of this file may be used under the terms of
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  34  * ***** END LICENSE BLOCK ***** */
  35
  36 #include "leaky.h"
  37
  38 #ifdef USE_ELF
  39
  40 #include "leaky.h"
  41 #include <stdio.h>
  42 #include <malloc.h>
  43 #include <libelf/libelf.h>
  44 #include <unistd.h>
  45 #include <fcntl.h>
  46 #include <string.h>
  47
  48 void leaky::readSymbols(const char *fileName)
  49 {
  50     int fd = ::open(fileName, O_RDONLY);
  51     if (fd < 0) {
  52         fprintf(stderr, "%s: unable to open \"%s\"\n", applicationName,
  53                 fileName);
  54         exit(-1);
  55     }
  56
  57     elf_version(EV_CURRENT);
  58     Elf *elf = elf_begin(fd, ELF_C_READ, 0);
  59     if (!elf) {
  60         fprintf(stderr, "%s: \"%s\": has no symbol table\n", applicationName,
  61                 fileName);
  62         exit(-1);
  63     }
  64
  65     long alloced = 10000;
  66     Symbol* syms = (Symbol*) malloc(sizeof(Symbol) * 10000);
  67     Symbol* sp = syms;
  68     Symbol* last = syms + alloced;
  69
  70     // Get each of the relevant sections and add them to the list of
  71     // symbols.
  72     Elf32_Ehdr *ehdr = elf32_getehdr(elf);
  73     if (!ehdr) {
  74         fprintf(stderr, "%s: elf library lossage\n", applicationName);
  75         exit(-1);
  76     }
  77 #if 0
  78     Elf32_Half ndx = ehdr->e_shstrndx;
  79 #endif
  80
  81     Elf_Scn *scn = 0;
  82     int strtabndx = -1;
  83     for (int i = 1; (scn = elf_nextscn(elf, scn)) != 0; i++) {
  84         Elf32_Shdr *shdr = elf32_getshdr(scn);
  85 #if 0
  86         char *name = elf_strptr(elf, ndx, (size_t) shdr->sh_name);
  87         printf("Section %s (%d 0x%x)\n", name ? name : "(null)",
  88                shdr->sh_type, shdr->sh_type);
  89 #endif
  90         if (shdr->sh_type == SHT_STRTAB) {
  91             /* We assume here that string tables preceed symbol tables... */
  92             strtabndx = i;
  93             continue;
  94         }
  95 #if 0
  96         if (shdr->sh_type == SHT_DYNAMIC) {
  97             /* Dynamic */
  98             Elf_Data *data = elf_getdata(scn, 0);
  99             if (!data || !data->d_size) {
 100                 printf("No data...");
 101                 continue;
 102             }
 103
 104             Elf32_Dyn *dyn = (Elf32_Dyn*) data->d_buf;
 105             Elf32_Dyn *lastdyn =
 106                 (Elf32_Dyn*) ((char*) data->d_buf + data->d_size);
 107             for (; dyn < lastdyn; dyn++) {
 108                 printf("tag=%d value=0x%x\n", dyn->d_tag, dyn->d_un.d_val);
 109             }
 110         } else
 111 #endif
 112         if ((shdr->sh_type == SHT_SYMTAB) ||
 113             (shdr->sh_type == SHT_DYNSYM)) {
 114             /* Symbol table */
 115             Elf_Data *data = elf_getdata(scn, 0);
 116             if (!data || !data->d_size) {
 117                 printf("No data...");
 118                 continue;
 119             }
 120
 121             /* In theory we now have the symbols... */
 122             Elf32_Sym *esym = (Elf32_Sym*) data->d_buf;
 123             Elf32_Sym *lastsym =
 124                 (Elf32_Sym*) ((char*) data->d_buf + data->d_size);
 125             for (; esym < lastsym; esym++) {
 126 #if 0
 127                 char *nm = elf_strptr(elf, strtabndx, (size_t)esym->st_name);
 128                 printf("%20s 0x%08x %02x %02x\n",
 129                        nm, esym->st_value, ELF32_ST_BIND(esym->st_info),
 130                        ELF32_ST_TYPE(esym->st_info));
 131 #endif
 132                 if ((esym->st_value == 0) ||
 133                     (ELF32_ST_BIND(esym->st_info) == STB_WEAK) ||
 134                     (ELF32_ST_BIND(esym->st_info) == STB_NUM) ||
 135                     (ELF32_ST_TYPE(esym->st_info) != STT_FUNC)) {
 136                     continue;
 137                 }
 138 #if 1
 139                 char *nm = elf_strptr(elf, strtabndx, (size_t)esym->st_name);
 140 #endif
 141                 sp->name = nm ? strdup(nm) : "(no name)";
 142                 sp->address = esym->st_value;
 143                 sp++;
 144                 if (sp >= last) {
 145                     long n = alloced + 10000;
 146                     syms = (Symbol*)
 147                         realloc(syms, (size_t) (sizeof(Symbol) * n));
 148                     last = syms + n;
 149                     sp = syms + alloced;
 150                     alloced = n;
 151                 }
 152             }
 153         }
 154     }
 155
 156     int interesting = sp - syms;
 157     if (!quiet) {
 158         printf("Total of %d symbols\n", interesting);
 159     }
 160     usefulSymbols = interesting;
 161     externalSymbols = syms;
 162 }
 163
 164 #endif /* USE_ELF */