diff -r 000000000000 -r 6474c204b198 tools/reorder/elf_symbol_table.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/reorder/elf_symbol_table.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,82 @@
+/* -*- Mode: C++ -*- */
+/* 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/. */
+
+#ifndef elf_symbol_table_h__
+#define elf_symbol_table_h__
+
+/*
+
+  Utility class for reading ELF symbol tables.
+
+ */
+
+#include <elf.h>
+#include <sys/mman.h>
+
+#include "interval_map.h"
+
+class elf_symbol_table {
+protected:
+    int              m_fd;
+    void            *m_mapping;
+    size_t           m_size;
+    const char      *m_strtab;
+    const Elf32_Sym *m_symbols;
+    int              m_nsymbols;
+    int              m_text_shndx;
+
+    typedef interval_map<unsigned int, const Elf32_Sym *> rsymtab_t;
+    rsymtab_t        m_rsymtab;
+
+    int verify_elf_header(const Elf32_Ehdr *hdr);
+    int finish();
+
+public:
+    elf_symbol_table()
+        : m_fd(-1),
+          m_mapping(MAP_FAILED),
+          m_size(0),
+          m_strtab(0),
+          m_symbols(0),
+          m_nsymbols(0),
+          m_text_shndx(0) {}
+
+    ~elf_symbol_table() { finish(); }
+
+    /**
+     * Read the symbol table information from the specified file. (This will
+     * memory-map the file.)
+     *
+     * Currently, only symbols from the `.text' section are loaded.
+     */
+    int init(const char *file);
+
+    /**
+     * Determine what symbol the specified image address corresponds
+     * to. Addresses need not refer to a symbol's start address:
+     * symbol size information is used to reverse-map the address.
+     */
+    const Elf32_Sym *lookup(unsigned int addr) const;
+
+    /**
+     * Determine the symbol name for the specified symbol.
+     */
+    const char *get_symbol_name(const Elf32_Sym *sym) const;
+
+    /**
+     * Return `true' if the specified symbol is a function.
+     */
+    bool is_function(const Elf32_Sym *sym) const {
+        return (sym->st_size > 0) &&
+            (ELF32_ST_TYPE(sym->st_info) == STT_FUNC) &&
+            (sym->st_shndx == m_text_shndx); }
+
+    typedef const Elf32_Sym *const_iterator;
+
+    const_iterator begin() const { return const_iterator(m_symbols); }
+    const_iterator end() const { return const_iterator(m_symbols + m_nsymbols); }
+};
+
+#endif // elf_symbol_table_h__