binutils-gdb/gold/stringpool.h
Ian Lance Taylor f0641a0b38 Rework stringpool and hash tables so that we always generate the same
output regardless of randomize_va_space.
2006-11-07 04:40:46 +00:00

150 lines
3.6 KiB
C++

// stringpool.h -- a string pool for gold -*- C++ -*-
#include <string>
#include <list>
// Stringpool
// Manage a pool of unique strings.
#ifndef GOLD_STRINGPOOL_H
#define GOLD_STRINGPOOL_H
namespace gold
{
class Output_file;
class Stringpool
{
public:
// The type of a key into the stringpool. A key value will always
// be the same during any run of the linker. The string pointers
// may change when using address space randomization. We use key
// values in order to get repeatable runs when the value is inserted
// into an unordered hash table. Zero is never a valid key.
typedef size_t Key;
Stringpool();
~Stringpool();
// Add a string to the pool. This returns a canonical permanent
// pointer to the string. If PKEY is not NULL, this sets *PKEY to
// the key for the string.
const char*
add(const char*, Key* pkey);
const char*
add(const std::string& s, Key* pkey)
{ return this->add(s.c_str(), pkey); }
// Add the prefix of a string to the pool.
const char*
add(const char *, size_t, Key* pkey);
// If a string is present, return the canonical string. Otherwise,
// return NULL. If PKEY is not NULL, set *PKEY to the key.
const char*
find(const char*, Key* pkey) const;
// Turn the stringpool into an ELF strtab: determine the offsets of
// all the strings.
void
set_string_offsets();
// Get the offset of a string in an ELF strtab.
off_t
get_offset(const char*) const;
off_t
get_offset(const std::string& s) const
{ return this->get_offset(s.c_str()); }
// Get the size of the ELF strtab.
off_t
get_strtab_size() const
{ return this->strtab_size_; }
// Write the strtab into the output file at the specified offset.
void
write(Output_file*, off_t offset);
private:
Stringpool(const Stringpool&);
Stringpool& operator=(const Stringpool&);
// We store the actual data in a list of these buffers.
struct Stringdata
{
// Length of data in buffer.
size_t len;
// Allocated size of buffer.
size_t alc;
// Buffer index.
unsigned int index;
// Buffer.
char data[1];
};
// Copy a string into the buffers, returning a canonical string.
const char*
add_string(const char*, Key*);
struct Stringpool_hash
{
size_t
operator()(const char*) const;
};
struct Stringpool_eq
{
bool
operator()(const char* p1, const char* p2) const
{ return strcmp(p1, p2) == 0; }
};
// Return whether s1 is a suffix of s2.
static bool is_suffix(const char* s1, const char* s2);
// The hash table is a map from string names to a pair of Key and
// ELF strtab offsets. We only use the offsets if we turn this into
// an ELF strtab section.
typedef std::pair<Key, off_t> Val;
#ifdef HAVE_TR1_UNORDERED_SET
typedef Unordered_map<const char*, Val, Stringpool_hash,
Stringpool_eq,
std::allocator<std::pair<const char* const, Val> >,
true> String_set_type;
#else
typedef Unordered_map<const char*, Val, Stringpool_hash,
Stringpool_eq> String_set_type;
#endif
// Comparison routine used when sorting into an ELF strtab.
struct Stringpool_sort_comparison
{
bool
operator()(String_set_type::iterator,
String_set_type::iterator) const;
};
// List of Stringdata structures.
typedef std::list<Stringdata*> Stringdata_list;
// Mapping from const char* to namepool entry.
String_set_type string_set_;
// List of buffers.
Stringdata_list strings_;
// Size of ELF strtab.
off_t strtab_size_;
// Next Stringdata index.
unsigned int next_index_;
};
} // End namespace gold.
#endif // !defined(GOLD_STRINGPOOL_H)