g++ 3.2.2 portability for grhat.
[deliverable/binutils-gdb.git] / gold / symtab.cc
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1// symtab.cc -- the gold symbol table
2
3#include "gold.h"
4
5#include <cassert>
6#include <stdint.h>
7#include <string>
8#include <utility>
9
10#include "object.h"
11#include "symtab.h"
12
13namespace gold
14{
15
16// Class Symbol.
17
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18// Initialize the fields in the base class Symbol.
19
20template<int size, bool big_endian>
21void
22Symbol::init_base(const char* name, const char* version, Object* object,
23 const elfcpp::Sym<size, big_endian>& sym)
24{
25 this->name_ = name;
26 this->version_ = version;
27 this->object_ = object;
28 this->shnum_ = sym.get_st_shndx(); // FIXME: Handle SHN_XINDEX.
29 this->type_ = sym.get_st_type();
30 this->binding_ = sym.get_st_bind();
31 this->visibility_ = sym.get_st_visibility();
32 this->other_ = sym.get_st_nonvis();
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33 this->is_special_ = false;
34 this->is_def_ = false;
35 this->is_forwarder_ = false;
36 this->in_dyn_ = object->is_dynamic();
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37}
38
39// Initialize the fields in Sized_symbol.
40
41template<int size>
42template<bool big_endian>
43void
44Sized_symbol<size>::init(const char* name, const char* version, Object* object,
45 const elfcpp::Sym<size, big_endian>& sym)
46{
47 this->init_base(name, version, object, sym);
48 this->value_ = sym.get_st_value();
49 this->size_ = sym.get_st_size();
50}
51
52// Class Symbol_table.
53
54Symbol_table::Symbol_table()
54dc6425 55 : size_(0), table_(), namepool_(), output_pool_(), forwarders_()
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56{
57}
58
59Symbol_table::~Symbol_table()
60{
61}
62
63// The hash function. The key is always canonicalized, so we use a
64// simple combination of the pointers.
65
66size_t
67Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
68{
69 return (reinterpret_cast<size_t>(key.first)
70 ^ reinterpret_cast<size_t>(key.second));
71}
72
73// The symbol table key equality function. This is only called with
74// canonicalized name and version strings, so we can use pointer
75// comparison.
76
77bool
78Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
79 const Symbol_table_key& k2) const
80{
81 return k1.first == k2.first && k1.second == k2.second;
82}
83
84// Make TO a symbol which forwards to FROM.
85
86void
87Symbol_table::make_forwarder(Symbol* from, Symbol* to)
88{
89 assert(!from->is_forwarder() && !to->is_forwarder());
90 this->forwarders_[from] = to;
91 from->set_forwarder();
92}
93
94Symbol*
95Symbol_table::resolve_forwards(Symbol* from) const
96{
97 assert(from->is_forwarder());
98 Unordered_map<Symbol*, Symbol*>::const_iterator p =
99 this->forwarders_.find(from);
100 assert(p != this->forwarders_.end());
101 return p->second;
102}
103
104// Resolve a Symbol with another Symbol. This is only used in the
105// unusual case where there are references to both an unversioned
106// symbol and a symbol with a version, and we then discover that that
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107// version is the default version. Because this is unusual, we do
108// this the slow way, by converting back to an ELF symbol.
14bfc3f5 109
1564db8d 110template<int size, bool big_endian>
14bfc3f5 111void
1564db8d 112Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
14bfc3f5 113{
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114 unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
115 elfcpp::Sym_write<size, big_endian> esym(buf);
116 // We don't bother to set the st_name field.
117 esym.put_st_value(from->value());
118 esym.put_st_size(from->symsize());
119 esym.put_st_info(from->binding(), from->type());
120 esym.put_st_other(from->visibility(), from->other());
121 esym.put_st_shndx(from->shnum());
122 Symbol_table::resolve(to, esym.sym(), from->object());
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123}
124
125// Add one symbol from OBJECT to the symbol table. NAME is symbol
126// name and VERSION is the version; both are canonicalized. DEF is
127// whether this is the default version.
128
129// If DEF is true, then this is the definition of a default version of
130// a symbol. That means that any lookup of NAME/NULL and any lookup
131// of NAME/VERSION should always return the same symbol. This is
132// obvious for references, but in particular we want to do this for
133// definitions: overriding NAME/NULL should also override
134// NAME/VERSION. If we don't do that, it would be very hard to
135// override functions in a shared library which uses versioning.
136
137// We implement this by simply making both entries in the hash table
138// point to the same Symbol structure. That is easy enough if this is
139// the first time we see NAME/NULL or NAME/VERSION, but it is possible
140// that we have seen both already, in which case they will both have
141// independent entries in the symbol table. We can't simply change
142// the symbol table entry, because we have pointers to the entries
143// attached to the object files. So we mark the entry attached to the
144// object file as a forwarder, and record it in the forwarders_ map.
145// Note that entries in the hash table will never be marked as
146// forwarders.
147
148template<int size, bool big_endian>
149Symbol*
150Symbol_table::add_from_object(Sized_object<size, big_endian>* object,
151 const char *name,
152 const char *version, bool def,
153 const elfcpp::Sym<size, big_endian>& sym)
154{
155 Symbol* const snull = NULL;
156 std::pair<typename Symbol_table_type::iterator, bool> ins =
157 this->table_.insert(std::make_pair(std::make_pair(name, version), snull));
158
159 std::pair<typename Symbol_table_type::iterator, bool> insdef =
160 std::make_pair(this->table_.end(), false);
161 if (def)
162 {
163 const char* const vnull = NULL;
164 insdef = this->table_.insert(std::make_pair(std::make_pair(name, vnull),
165 snull));
166 }
167
168 // ins.first: an iterator, which is a pointer to a pair.
169 // ins.first->first: the key (a pair of name and version).
170 // ins.first->second: the value (Symbol*).
171 // ins.second: true if new entry was inserted, false if not.
172
1564db8d 173 Sized_symbol<size>* ret;
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174 if (!ins.second)
175 {
176 // We already have an entry for NAME/VERSION.
1564db8d 177 ret = this->get_sized_symbol<size>(ins.first->second);
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178 assert(ret != NULL);
179 Symbol_table::resolve(ret, sym, object);
180
181 if (def)
182 {
183 if (insdef.second)
184 {
185 // This is the first time we have seen NAME/NULL. Make
186 // NAME/NULL point to NAME/VERSION.
187 insdef.first->second = ret;
188 }
189 else
190 {
191 // This is the unfortunate case where we already have
192 // entries for both NAME/VERSION and NAME/NULL.
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193 const Sized_symbol<size>* sym2 =
194 this->get_sized_symbol<size>(insdef.first->second);
195 Symbol_table::resolve<size, big_endian>(ret, sym2);
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196 this->make_forwarder(insdef.first->second, ret);
197 insdef.first->second = ret;
198 }
199 }
200 }
201 else
202 {
203 // This is the first time we have seen NAME/VERSION.
204 assert(ins.first->second == NULL);
205 if (def && !insdef.second)
206 {
207 // We already have an entry for NAME/NULL. Make
208 // NAME/VERSION point to it.
1564db8d 209 ret = this->get_sized_symbol<size>(insdef.first->second);
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210 Symbol_table::resolve(ret, sym, object);
211 ins.first->second = ret;
212 }
213 else
214 {
14bfc3f5 215 Sized_target<size, big_endian>* target = object->sized_target();
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216 if (!target->has_make_symbol())
217 ret = new Sized_symbol<size>();
218 else
14bfc3f5 219 {
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220 ret = target->make_symbol();
221 if (ret == NULL)
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222 {
223 // This means that we don't want a symbol table
224 // entry after all.
225 if (!def)
226 this->table_.erase(ins.first);
227 else
228 {
229 this->table_.erase(insdef.first);
230 // Inserting insdef invalidated ins.
231 this->table_.erase(std::make_pair(name, version));
232 }
233 return NULL;
234 }
235 }
14bfc3f5 236
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237 ret->init(name, version, object, sym);
238
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239 ins.first->second = ret;
240 if (def)
241 {
242 // This is the first time we have seen NAME/NULL. Point
243 // it at the new entry for NAME/VERSION.
244 assert(insdef.second);
245 insdef.first->second = ret;
246 }
247 }
248 }
249
250 return ret;
251}
252
253// Add all the symbols in an object to the hash table.
254
255template<int size, bool big_endian>
256void
257Symbol_table::add_from_object(
258 Sized_object<size, big_endian>* object,
259 const elfcpp::Sym<size, big_endian>* syms,
260 size_t count,
261 const char* sym_names,
262 size_t sym_name_size,
263 Symbol** sympointers)
264{
265 // We take the size from the first object we see.
266 if (this->get_size() == 0)
267 this->set_size(size);
268
269 if (size != this->get_size() || size != object->target()->get_size())
270 {
271 fprintf(stderr, _("%s: %s: mixing 32-bit and 64-bit ELF objects\n"),
272 program_name, object->name().c_str());
273 gold_exit(false);
274 }
275
276 const unsigned char* p = reinterpret_cast<const unsigned char*>(syms);
277 for (size_t i = 0; i < count; ++i)
278 {
279 elfcpp::Sym<size, big_endian> sym(p);
280
281 unsigned int st_name = sym.get_st_name();
282 if (st_name >= sym_name_size)
283 {
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284 fprintf(stderr,
285 _("%s: %s: bad global symbol name offset %u at %lu\n"),
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286 program_name, object->name().c_str(), st_name,
287 static_cast<unsigned long>(i));
288 gold_exit(false);
289 }
290
291 const char* name = sym_names + st_name;
292
293 // In an object file, an '@' in the name separates the symbol
294 // name from the version name. If there are two '@' characters,
295 // this is the default version.
296 const char* ver = strchr(name, '@');
297
298 Symbol* res;
299 if (ver == NULL)
300 {
301 name = this->namepool_.add(name);
302 res = this->add_from_object(object, name, NULL, false, sym);
303 }
304 else
305 {
306 name = this->namepool_.add(name, ver - name);
307 bool def = false;
308 ++ver;
309 if (*ver == '@')
310 {
311 def = true;
312 ++ver;
313 }
314 ver = this->namepool_.add(ver);
315 res = this->add_from_object(object, name, ver, def, sym);
316 }
317
318 *sympointers++ = res;
319
320 p += elfcpp::Elf_sizes<size>::sym_size;
321 }
322}
323
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324// Record the names of the local symbols for an object.
325
326template<int size, bool big_endian>
327void
328Symbol_table::add_local_symbol_names(Sized_object<size, big_endian>* object,
329 const elfcpp::Sym<size, big_endian>* syms,
330 size_t count, const char* sym_names,
331 size_t sym_name_size)
332{
333 const unsigned char* p = reinterpret_cast<const unsigned char*>(syms);
334 for (size_t i = 0; i < count; ++i)
335 {
336 elfcpp::Sym<size, big_endian> sym(p);
337
338 unsigned int st_name = sym.get_st_name();
339 if (st_name >= sym_name_size)
340 {
341 fprintf(stderr,
342 _("%s: %s: bad local symbol name offset %u at %lu\n"),
343 program_name, object->name().c_str(), st_name,
344 static_cast<unsigned long>(i));
345 gold_exit(false);
346 }
347
348 this->output_pool_.add(sym_names + st_name);
349 }
350}
351
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352// Instantiate the templates we need. We could use the configure
353// script to restrict this to only the ones needed for implemented
354// targets.
355
356template
357void
358Symbol_table::add_from_object<32, true>(
359 Sized_object<32, true>* object,
360 const elfcpp::Sym<32, true>* syms,
361 size_t count,
362 const char* sym_names,
363 size_t sym_name_size,
364 Symbol** sympointers);
365
366template
367void
368Symbol_table::add_from_object<32, false>(
369 Sized_object<32, false>* object,
370 const elfcpp::Sym<32, false>* syms,
371 size_t count,
372 const char* sym_names,
373 size_t sym_name_size,
374 Symbol** sympointers);
375
376template
377void
378Symbol_table::add_from_object<64, true>(
379 Sized_object<64, true>* object,
380 const elfcpp::Sym<64, true>* syms,
381 size_t count,
382 const char* sym_names,
383 size_t sym_name_size,
384 Symbol** sympointers);
385
386template
387void
388Symbol_table::add_from_object<64, false>(
389 Sized_object<64, false>* object,
390 const elfcpp::Sym<64, false>* syms,
391 size_t count,
392 const char* sym_names,
393 size_t sym_name_size,
394 Symbol** sympointers);
395
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396template
397void
398Symbol_table::add_local_symbol_names<32, true>(
399 Sized_object<32, true>* object,
400 const elfcpp::Sym<32, true>* syms,
401 size_t count,
402 const char* sym_names,
403 size_t sym_name_size);
404
405template
406void
407Symbol_table::add_local_symbol_names<32, false>(
408 Sized_object<32, false>* object,
409 const elfcpp::Sym<32, false>* syms,
410 size_t count,
411 const char* sym_names,
412 size_t sym_name_size);
413
414template
415void
416Symbol_table::add_local_symbol_names<64, true>(
417 Sized_object<64, true>* object,
418 const elfcpp::Sym<64, true>* syms,
419 size_t count,
420 const char* sym_names,
421 size_t sym_name_size);
422
423template
424void
425Symbol_table::add_local_symbol_names<64, false>(
426 Sized_object<64, false>* object,
427 const elfcpp::Sym<64, false>* syms,
428 size_t count,
429 const char* sym_names,
430 size_t sym_name_size);
431
14bfc3f5 432} // End namespace gold.
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