diff -r 000000000000 -r 6474c204b198 tools/reorder/elf_symbol_table.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/reorder/elf_symbol_table.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,117 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <string>
+#include <fstream>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "elf_symbol_table.h"
+#include "elf_utils.h"
+
+int
+elf_symbol_table::init(const char *name)
+{
+    // Open the file readonly.
+    m_fd = open(name, O_RDONLY);
+    if (m_fd < 0) {
+        perror(name);
+        return m_fd;
+    }
+
+    // Get its size.
+    struct stat statbuf;
+    if (fstat(m_fd, &statbuf) < 0) {
+        perror(name);
+        return -1;
+    }
+
+    m_size = statbuf.st_size;
+
+    // Memory map it.
+    m_mapping = mmap(0, m_size, PROT_READ, MAP_SHARED, m_fd, 0);
+    if (m_mapping == MAP_FAILED) {
+        perror(name);
+        return -1;
+    }
+
+    // Make sure it's an ELF header.
+    const Elf32_Ehdr *ehdr = reinterpret_cast<const Elf32_Ehdr *>(m_mapping);
+    if (elf_verify_header(ehdr) < 0)
+        return -1;
+
+    const char *mapping = reinterpret_cast<const char *>(m_mapping);
+
+    // Find the section headers
+    const Elf32_Shdr *shdrs
+        = reinterpret_cast<const Elf32_Shdr *>(mapping + ehdr->e_shoff);
+
+    // find the section header string table, .shstrtab
+    const Elf32_Shdr *shstrtabsh = shdrs + ehdr->e_shstrndx;
+    const char *shstrtab = mapping + shstrtabsh->sh_offset;
+
+    // parse the sections we care about
+    int shndx = 0;
+    const Elf32_Shdr *shlimit = shdrs + ehdr->e_shnum;
+    for (const Elf32_Shdr *shdr = shdrs; shdr < shlimit; ++shdr, ++shndx) {
+        basic_string<char> name(shstrtab + shdr->sh_name);
+        if (name == ".symtab") {
+            m_symbols = reinterpret_cast<const Elf32_Sym *>(mapping + shdr->sh_offset);
+            m_nsymbols = shdr->sh_size / sizeof(Elf32_Sym);
+        }
+        else if (name == ".strtab") {
+            m_strtab = mapping + shdr->sh_offset;
+        }
+        else if (name == ".text") {
+            m_text_shndx = shndx;
+        }
+    }
+
+    // Parse the symbol table
+    const Elf32_Sym *limit = m_symbols + m_nsymbols;
+    for (const Elf32_Sym *sym = m_symbols; sym < limit; ++sym) {
+        if (is_function(sym)) {
+#ifdef DEBUG
+            hex(cout);
+            cout << sym->st_value << endl;
+#endif
+            m_rsymtab.put(sym->st_value, sym->st_value + sym->st_size, sym);
+        }
+    }
+
+    return 0;
+}
+
+int
+elf_symbol_table::finish()
+{
+    if (m_mapping != MAP_FAILED) {
+        munmap(m_mapping, m_size);
+        m_mapping = MAP_FAILED;
+    }
+
+    if (m_fd >= 0) {
+        close(m_fd);
+        m_fd = -1;
+    }
+
+    return 0;
+}
+
+const Elf32_Sym *
+elf_symbol_table::lookup(unsigned int addr) const
+{
+    rsymtab_t::const_iterator result = m_rsymtab.get(addr);
+    return result != m_rsymtab.end() ? reinterpret_cast<const Elf32_Sym *>(*result) : 0;
+}
+
+const char *
+elf_symbol_table::get_symbol_name(const Elf32_Sym *sym) const
+{
+    return m_strtab + sym->st_name;
+}