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3151305a ILT |
1 | // ehframe.cc -- handle exception frame sections for gold |
2 | ||
219d1afa | 3 | // Copyright (C) 2006-2018 Free Software Foundation, Inc. |
3151305a ILT |
4 | // Written by Ian Lance Taylor <iant@google.com>. |
5 | ||
6 | // This file is part of gold. | |
7 | ||
8 | // This program is free software; you can redistribute it and/or modify | |
9 | // it under the terms of the GNU General Public License as published by | |
10 | // the Free Software Foundation; either version 3 of the License, or | |
11 | // (at your option) any later version. | |
12 | ||
13 | // This program is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | ||
18 | // You should have received a copy of the GNU General Public License | |
19 | // along with this program; if not, write to the Free Software | |
20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
21 | // MA 02110-1301, USA. | |
22 | ||
23 | #include "gold.h" | |
24 | ||
730cdc88 ILT |
25 | #include <cstring> |
26 | #include <algorithm> | |
27 | ||
3151305a ILT |
28 | #include "elfcpp.h" |
29 | #include "dwarf.h" | |
730cdc88 ILT |
30 | #include "symtab.h" |
31 | #include "reloc.h" | |
3151305a ILT |
32 | #include "ehframe.h" |
33 | ||
34 | namespace gold | |
35 | { | |
36 | ||
37 | // This file handles generation of the exception frame header that | |
38 | // gcc's runtime support libraries use to find unwind information at | |
730cdc88 ILT |
39 | // runtime. This file also handles discarding duplicate exception |
40 | // frame information. | |
3151305a ILT |
41 | |
42 | // The exception frame header starts with four bytes: | |
43 | ||
44 | // 0: The version number, currently 1. | |
45 | ||
46 | // 1: The encoding of the pointer to the exception frames. This can | |
47 | // be any DWARF unwind encoding (DW_EH_PE_*). It is normally a 4 | |
48 | // byte PC relative offset (DW_EH_PE_pcrel | DW_EH_PE_sdata4). | |
49 | ||
50 | // 2: The encoding of the count of the number of FDE pointers in the | |
51 | // lookup table. This can be any DWARF unwind encoding, and in | |
52 | // particular can be DW_EH_PE_omit if the count is omitted. It is | |
53 | // normally a 4 byte unsigned count (DW_EH_PE_udata4). | |
54 | ||
55 | // 3: The encoding of the lookup table entries. Currently gcc's | |
56 | // libraries will only support DW_EH_PE_datarel | DW_EH_PE_sdata4, | |
57 | // which means that the values are 4 byte offsets from the start of | |
58 | // the table. | |
59 | ||
60 | // The exception frame header is followed by a pointer to the contents | |
61 | // of the exception frame section (.eh_frame). This pointer is | |
62 | // encoded as specified in the byte at offset 1 of the header (i.e., | |
63 | // it is normally a 4 byte PC relative offset). | |
64 | ||
65 | // If there is a lookup table, this is followed by the count of the | |
66 | // number of FDE pointers, encoded as specified in the byte at offset | |
67 | // 2 of the header (i.e., normally a 4 byte unsigned integer). | |
68 | ||
69 | // This is followed by the table, which should start at an 4-byte | |
70 | // aligned address in memory. Each entry in the table is 8 bytes. | |
71 | // Each entry represents an FDE. The first four bytes of each entry | |
72 | // are an offset to the starting PC for the FDE. The last four bytes | |
73 | // of each entry are an offset to the FDE data. The offsets are from | |
74 | // the start of the exception frame header information. The entries | |
75 | // are in sorted order by starting PC. | |
76 | ||
3151305a ILT |
77 | const int eh_frame_hdr_size = 4; |
78 | ||
79 | // Construct the exception frame header. | |
80 | ||
730cdc88 ILT |
81 | Eh_frame_hdr::Eh_frame_hdr(Output_section* eh_frame_section, |
82 | const Eh_frame* eh_frame_data) | |
3151305a | 83 | : Output_section_data(4), |
730cdc88 ILT |
84 | eh_frame_section_(eh_frame_section), |
85 | eh_frame_data_(eh_frame_data), | |
86 | fde_offsets_(), | |
cafdd569 | 87 | any_unrecognized_eh_frame_sections_(false) |
3151305a ILT |
88 | { |
89 | } | |
90 | ||
27bc2bce | 91 | // Set the size of the exception frame header. |
3151305a ILT |
92 | |
93 | void | |
27bc2bce | 94 | Eh_frame_hdr::set_final_data_size() |
3151305a | 95 | { |
2ea97941 | 96 | unsigned int data_size = eh_frame_hdr_size + 4; |
730cdc88 ILT |
97 | if (!this->any_unrecognized_eh_frame_sections_) |
98 | { | |
99 | unsigned int fde_count = this->eh_frame_data_->fde_count(); | |
100 | if (fde_count != 0) | |
2ea97941 | 101 | data_size += 4 + 8 * fde_count; |
730cdc88 ILT |
102 | this->fde_offsets_.reserve(fde_count); |
103 | } | |
2ea97941 | 104 | this->set_data_size(data_size); |
3151305a ILT |
105 | } |
106 | ||
9b547ce6 | 107 | // Write the data to the file. |
3151305a ILT |
108 | |
109 | void | |
110 | Eh_frame_hdr::do_write(Output_file* of) | |
730cdc88 | 111 | { |
8851ecca | 112 | switch (parameters->size_and_endianness()) |
730cdc88 | 113 | { |
730cdc88 | 114 | #ifdef HAVE_TARGET_32_LITTLE |
8851ecca ILT |
115 | case Parameters::TARGET_32_LITTLE: |
116 | this->do_sized_write<32, false>(of); | |
117 | break; | |
730cdc88 | 118 | #endif |
730cdc88 | 119 | #ifdef HAVE_TARGET_32_BIG |
8851ecca ILT |
120 | case Parameters::TARGET_32_BIG: |
121 | this->do_sized_write<32, true>(of); | |
122 | break; | |
730cdc88 | 123 | #endif |
730cdc88 | 124 | #ifdef HAVE_TARGET_64_LITTLE |
8851ecca ILT |
125 | case Parameters::TARGET_64_LITTLE: |
126 | this->do_sized_write<64, false>(of); | |
127 | break; | |
730cdc88 | 128 | #endif |
730cdc88 | 129 | #ifdef HAVE_TARGET_64_BIG |
8851ecca ILT |
130 | case Parameters::TARGET_64_BIG: |
131 | this->do_sized_write<64, true>(of); | |
132 | break; | |
730cdc88 | 133 | #endif |
8851ecca ILT |
134 | default: |
135 | gold_unreachable(); | |
730cdc88 | 136 | } |
730cdc88 ILT |
137 | } |
138 | ||
139 | // Write the data to the file with the right endianness. | |
140 | ||
141 | template<int size, bool big_endian> | |
142 | void | |
143 | Eh_frame_hdr::do_sized_write(Output_file* of) | |
3151305a ILT |
144 | { |
145 | const off_t off = this->offset(); | |
146 | const off_t oview_size = this->data_size(); | |
147 | unsigned char* const oview = of->get_output_view(off, oview_size); | |
148 | ||
149 | // Version number. | |
150 | oview[0] = 1; | |
151 | ||
152 | // Write out a 4 byte PC relative offset to the address of the | |
153 | // .eh_frame section. | |
154 | oview[1] = elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4; | |
155 | uint64_t eh_frame_address = this->eh_frame_section_->address(); | |
156 | uint64_t eh_frame_hdr_address = this->address(); | |
157 | uint64_t eh_frame_offset = (eh_frame_address - | |
158 | (eh_frame_hdr_address + 4)); | |
730cdc88 ILT |
159 | elfcpp::Swap<32, big_endian>::writeval(oview + 4, eh_frame_offset); |
160 | ||
161 | if (this->any_unrecognized_eh_frame_sections_ | |
162 | || this->fde_offsets_.empty()) | |
163 | { | |
164 | // There are no FDEs, or we didn't recognize the format of the | |
165 | // some of the .eh_frame sections, so we can't write out the | |
166 | // sorted table. | |
167 | oview[2] = elfcpp::DW_EH_PE_omit; | |
168 | oview[3] = elfcpp::DW_EH_PE_omit; | |
169 | ||
170 | gold_assert(oview_size == 8); | |
171 | } | |
3151305a | 172 | else |
730cdc88 ILT |
173 | { |
174 | oview[2] = elfcpp::DW_EH_PE_udata4; | |
175 | oview[3] = elfcpp::DW_EH_PE_datarel | elfcpp::DW_EH_PE_sdata4; | |
176 | ||
177 | elfcpp::Swap<32, big_endian>::writeval(oview + 8, | |
178 | this->fde_offsets_.size()); | |
179 | ||
180 | // We have the offsets of the FDEs in the .eh_frame section. We | |
181 | // couldn't easily get the PC values before, as they depend on | |
182 | // relocations which are, of course, target specific. This code | |
183 | // is run after all those relocations have been applied to the | |
184 | // output file. Here we read the output file again to find the | |
185 | // PC values. Then we sort the list and write it out. | |
3151305a | 186 | |
730cdc88 ILT |
187 | Fde_addresses<size> fde_addresses(this->fde_offsets_.size()); |
188 | this->get_fde_addresses<size, big_endian>(of, &this->fde_offsets_, | |
189 | &fde_addresses); | |
3151305a | 190 | |
730cdc88 ILT |
191 | std::sort(fde_addresses.begin(), fde_addresses.end(), |
192 | Fde_address_compare<size>()); | |
193 | ||
194 | typename elfcpp::Elf_types<size>::Elf_Addr output_address; | |
195 | output_address = this->address(); | |
196 | ||
197 | unsigned char* pfde = oview + 12; | |
198 | for (typename Fde_addresses<size>::iterator p = fde_addresses.begin(); | |
199 | p != fde_addresses.end(); | |
200 | ++p) | |
201 | { | |
202 | elfcpp::Swap<32, big_endian>::writeval(pfde, | |
203 | p->first - output_address); | |
204 | elfcpp::Swap<32, big_endian>::writeval(pfde + 4, | |
205 | p->second - output_address); | |
206 | pfde += 8; | |
207 | } | |
208 | ||
209 | gold_assert(pfde - oview == oview_size); | |
210 | } | |
3151305a ILT |
211 | |
212 | of->write_output_view(off, oview_size, oview); | |
213 | } | |
214 | ||
730cdc88 ILT |
215 | // Given the offset FDE_OFFSET of an FDE in the .eh_frame section, and |
216 | // the contents of the .eh_frame section EH_FRAME_CONTENTS, where the | |
217 | // FDE's encoding is FDE_ENCODING, return the output address of the | |
218 | // FDE's PC. | |
219 | ||
220 | template<int size, bool big_endian> | |
221 | typename elfcpp::Elf_types<size>::Elf_Addr | |
4117d768 ILT |
222 | Eh_frame_hdr::get_fde_pc( |
223 | typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address, | |
224 | const unsigned char* eh_frame_contents, | |
8383303e | 225 | section_offset_type fde_offset, |
4117d768 | 226 | unsigned char fde_encoding) |
730cdc88 ILT |
227 | { |
228 | // The FDE starts with a 4 byte length and a 4 byte offset to the | |
229 | // CIE. The PC follows. | |
230 | const unsigned char* p = eh_frame_contents + fde_offset + 8; | |
231 | ||
232 | typename elfcpp::Elf_types<size>::Elf_Addr pc; | |
233 | bool is_signed = (fde_encoding & elfcpp::DW_EH_PE_signed) != 0; | |
234 | int pc_size = fde_encoding & 7; | |
235 | if (pc_size == elfcpp::DW_EH_PE_absptr) | |
236 | { | |
237 | if (size == 32) | |
238 | pc_size = elfcpp::DW_EH_PE_udata4; | |
239 | else if (size == 64) | |
240 | pc_size = elfcpp::DW_EH_PE_udata8; | |
241 | else | |
242 | gold_unreachable(); | |
243 | } | |
244 | ||
245 | switch (pc_size) | |
246 | { | |
247 | case elfcpp::DW_EH_PE_udata2: | |
248 | pc = elfcpp::Swap<16, big_endian>::readval(p); | |
249 | if (is_signed) | |
250 | pc = (pc ^ 0x8000) - 0x8000; | |
251 | break; | |
252 | ||
253 | case elfcpp::DW_EH_PE_udata4: | |
254 | pc = elfcpp::Swap<32, big_endian>::readval(p); | |
255 | if (size > 32 && is_signed) | |
256 | pc = (pc ^ 0x80000000) - 0x80000000; | |
257 | break; | |
258 | ||
259 | case elfcpp::DW_EH_PE_udata8: | |
260 | gold_assert(size == 64); | |
261 | pc = elfcpp::Swap_unaligned<64, big_endian>::readval(p); | |
262 | break; | |
263 | ||
264 | default: | |
4117d768 ILT |
265 | // All other cases were rejected in Eh_frame::read_cie. |
266 | gold_unreachable(); | |
267 | } | |
268 | ||
02d7cd44 | 269 | switch (fde_encoding & 0x70) |
4117d768 ILT |
270 | { |
271 | case 0: | |
272 | break; | |
273 | ||
274 | case elfcpp::DW_EH_PE_pcrel: | |
275 | pc += eh_frame_address + fde_offset + 8; | |
276 | break; | |
277 | ||
02d7cd44 ILT |
278 | case elfcpp::DW_EH_PE_datarel: |
279 | pc += parameters->target().ehframe_datarel_base(); | |
280 | break; | |
281 | ||
4117d768 ILT |
282 | default: |
283 | // If other cases arise, then we have to handle them, or we have | |
284 | // to reject them by returning false in Eh_frame::read_cie. | |
730cdc88 ILT |
285 | gold_unreachable(); |
286 | } | |
287 | ||
02d7cd44 ILT |
288 | gold_assert((fde_encoding & elfcpp::DW_EH_PE_indirect) == 0); |
289 | ||
730cdc88 ILT |
290 | return pc; |
291 | } | |
292 | ||
293 | // Given an array of FDE offsets in the .eh_frame section, return an | |
294 | // array of offsets from the exception frame header to the FDE's | |
295 | // output PC and to the output address of the FDE itself. We get the | |
296 | // FDE's PC by actually looking in the .eh_frame section we just wrote | |
297 | // to the output file. | |
298 | ||
299 | template<int size, bool big_endian> | |
300 | void | |
301 | Eh_frame_hdr::get_fde_addresses(Output_file* of, | |
302 | const Fde_offsets* fde_offsets, | |
303 | Fde_addresses<size>* fde_addresses) | |
304 | { | |
305 | typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address; | |
306 | eh_frame_address = this->eh_frame_section_->address(); | |
307 | off_t eh_frame_offset = this->eh_frame_section_->offset(); | |
308 | off_t eh_frame_size = this->eh_frame_section_->data_size(); | |
309 | const unsigned char* eh_frame_contents = of->get_input_view(eh_frame_offset, | |
310 | eh_frame_size); | |
311 | ||
312 | for (Fde_offsets::const_iterator p = fde_offsets->begin(); | |
313 | p != fde_offsets->end(); | |
314 | ++p) | |
315 | { | |
316 | typename elfcpp::Elf_types<size>::Elf_Addr fde_pc; | |
4117d768 ILT |
317 | fde_pc = this->get_fde_pc<size, big_endian>(eh_frame_address, |
318 | eh_frame_contents, | |
730cdc88 ILT |
319 | p->first, p->second); |
320 | fde_addresses->push_back(fde_pc, eh_frame_address + p->first); | |
321 | } | |
322 | ||
323 | of->free_input_view(eh_frame_offset, eh_frame_size, eh_frame_contents); | |
324 | } | |
325 | ||
326 | // Class Fde. | |
327 | ||
be897fb7 AM |
328 | bool |
329 | Fde::operator==(const Fde& that) const | |
330 | { | |
331 | if (this->object_ != that.object_ | |
332 | || this->contents_ != that.contents_) | |
333 | return false; | |
334 | if (this->object_ == NULL) | |
335 | return (this->u_.from_linker.plt == that.u_.from_linker.plt | |
336 | && this->u_.from_linker.post_map == that.u_.from_linker.post_map); | |
337 | else | |
338 | return (this->u_.from_object.shndx == that.u_.from_object.shndx | |
339 | && (this->u_.from_object.input_offset | |
340 | == that.u_.from_object.input_offset)); | |
341 | } | |
342 | ||
730cdc88 | 343 | // Write the FDE to OVIEW starting at OFFSET. CIE_OFFSET is the |
9860cbcf CC |
344 | // offset of the CIE in OVIEW. OUTPUT_OFFSET is the offset of the |
345 | // Eh_frame section within the output section. FDE_ENCODING is the | |
346 | // encoding, from the CIE. ADDRALIGN is the required alignment. | |
347 | // ADDRESS is the virtual address of OVIEW. Record the FDE pc for | |
348 | // EH_FRAME_HDR. Return the new offset. | |
730cdc88 ILT |
349 | |
350 | template<int size, bool big_endian> | |
8383303e | 351 | section_offset_type |
9860cbcf CC |
352 | Fde::write(unsigned char* oview, section_offset_type output_offset, |
353 | section_offset_type offset, uint64_t address, unsigned int addralign, | |
07a60597 ILT |
354 | section_offset_type cie_offset, unsigned char fde_encoding, |
355 | Eh_frame_hdr* eh_frame_hdr) | |
730cdc88 | 356 | { |
935e8877 ILT |
357 | gold_assert((offset & (addralign - 1)) == 0); |
358 | ||
2ea97941 | 359 | size_t length = this->contents_.length(); |
730cdc88 | 360 | |
935e8877 ILT |
361 | // We add 8 when getting the aligned length to account for the |
362 | // length word and the CIE offset. | |
2ea97941 | 363 | size_t aligned_full_length = align_address(length + 8, addralign); |
935e8877 | 364 | |
730cdc88 ILT |
365 | // Write the length of the FDE as a 32-bit word. The length word |
366 | // does not include the four bytes of the length word itself, but it | |
367 | // does include the offset to the CIE. | |
368 | elfcpp::Swap<32, big_endian>::writeval(oview + offset, | |
935e8877 | 369 | aligned_full_length - 4); |
730cdc88 ILT |
370 | |
371 | // Write the offset to the CIE as a 32-bit word. This is the | |
372 | // difference between the address of the offset word itself and the | |
373 | // CIE address. | |
374 | elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4, | |
375 | offset + 4 - cie_offset); | |
376 | ||
377 | // Copy the rest of the FDE. Note that this is run before | |
378 | // relocation processing is done on this section, so the relocations | |
379 | // will later be applied to the FDE data. | |
2ea97941 | 380 | memcpy(oview + offset + 8, this->contents_.data(), length); |
730cdc88 | 381 | |
07a60597 ILT |
382 | // If this FDE is associated with a PLT, fill in the PLT's address |
383 | // and size. | |
384 | if (this->object_ == NULL) | |
385 | { | |
386 | gold_assert(memcmp(oview + offset + 8, "\0\0\0\0\0\0\0\0", 8) == 0); | |
9d5781f8 AM |
387 | uint64_t paddress; |
388 | off_t psize; | |
389 | parameters->target().plt_fde_location(this->u_.from_linker.plt, | |
390 | oview + offset + 8, | |
391 | &paddress, &psize); | |
392 | uint64_t poffset = paddress - (address + offset + 8); | |
07a60597 | 393 | int32_t spoffset = static_cast<int32_t>(poffset); |
07a60597 ILT |
394 | uint32_t upsize = static_cast<uint32_t>(psize); |
395 | if (static_cast<uint64_t>(static_cast<int64_t>(spoffset)) != poffset | |
396 | || static_cast<off_t>(upsize) != psize) | |
397 | gold_warning(_("overflow in PLT unwind data; " | |
398 | "unwinding through PLT may fail")); | |
399 | elfcpp::Swap<32, big_endian>::writeval(oview + offset + 8, spoffset); | |
400 | elfcpp::Swap<32, big_endian>::writeval(oview + offset + 12, upsize); | |
401 | } | |
402 | ||
2ea97941 ILT |
403 | if (aligned_full_length > length + 8) |
404 | memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8)); | |
935e8877 | 405 | |
730cdc88 ILT |
406 | // Tell the exception frame header about this FDE. |
407 | if (eh_frame_hdr != NULL) | |
9860cbcf | 408 | eh_frame_hdr->record_fde(output_offset + offset, fde_encoding); |
730cdc88 | 409 | |
935e8877 | 410 | return offset + aligned_full_length; |
730cdc88 ILT |
411 | } |
412 | ||
413 | // Class Cie. | |
414 | ||
415 | // Destructor. | |
416 | ||
417 | Cie::~Cie() | |
418 | { | |
419 | for (std::vector<Fde*>::iterator p = this->fdes_.begin(); | |
420 | p != this->fdes_.end(); | |
421 | ++p) | |
422 | delete *p; | |
423 | } | |
424 | ||
425 | // Set the output offset of a CIE. Return the new output offset. | |
426 | ||
8383303e ILT |
427 | section_offset_type |
428 | Cie::set_output_offset(section_offset_type output_offset, | |
429 | unsigned int addralign, | |
dbe40a88 | 430 | Output_section_data *output_data) |
730cdc88 ILT |
431 | { |
432 | size_t length = this->contents_.length(); | |
935e8877 | 433 | |
730cdc88 ILT |
434 | // Add 4 for length and 4 for zero CIE identifier tag. |
435 | length += 8; | |
436 | ||
07a60597 ILT |
437 | if (this->object_ != NULL) |
438 | { | |
439 | // Add a mapping so that relocations are applied correctly. | |
dbe40a88 RÁE |
440 | this->object_->add_merge_mapping(output_data, this->shndx_, |
441 | this->input_offset_, length, | |
442 | output_offset); | |
07a60597 | 443 | } |
730cdc88 | 444 | |
935e8877 ILT |
445 | length = align_address(length, addralign); |
446 | ||
730cdc88 ILT |
447 | for (std::vector<Fde*>::const_iterator p = this->fdes_.begin(); |
448 | p != this->fdes_.end(); | |
449 | ++p) | |
450 | { | |
dbe40a88 | 451 | (*p)->add_mapping(output_offset + length, output_data); |
730cdc88 ILT |
452 | |
453 | size_t fde_length = (*p)->length(); | |
935e8877 | 454 | fde_length = align_address(fde_length, addralign); |
730cdc88 ILT |
455 | length += fde_length; |
456 | } | |
457 | ||
458 | return output_offset + length; | |
459 | } | |
460 | ||
be897fb7 AM |
461 | // Remove FDE. Only the last FDE using this CIE may be removed. |
462 | ||
463 | void | |
464 | Cie::remove_fde(const Fde* fde) | |
465 | { | |
466 | gold_assert(*fde == *this->fdes_.back()); | |
467 | this->fdes_.pop_back(); | |
468 | } | |
469 | ||
9860cbcf CC |
470 | // Write the CIE to OVIEW starting at OFFSET. OUTPUT_OFFSET is the |
471 | // offset of the Eh_frame section within the output section. Round up | |
472 | // the bytes to ADDRALIGN. ADDRESS is the virtual address of OVIEW. | |
9d5781f8 AM |
473 | // EH_FRAME_HDR is the exception frame header for FDE recording. |
474 | // POST_FDES stashes FDEs created after mappings were done, for later | |
475 | // writing. Return the new offset. | |
730cdc88 ILT |
476 | |
477 | template<int size, bool big_endian> | |
8383303e | 478 | section_offset_type |
9860cbcf CC |
479 | Cie::write(unsigned char* oview, section_offset_type output_offset, |
480 | section_offset_type offset, uint64_t address, | |
481 | unsigned int addralign, Eh_frame_hdr* eh_frame_hdr, | |
482 | Post_fdes* post_fdes) | |
730cdc88 | 483 | { |
935e8877 ILT |
484 | gold_assert((offset & (addralign - 1)) == 0); |
485 | ||
8383303e | 486 | section_offset_type cie_offset = offset; |
730cdc88 ILT |
487 | |
488 | size_t length = this->contents_.length(); | |
489 | ||
935e8877 ILT |
490 | // We add 8 when getting the aligned length to account for the |
491 | // length word and the CIE tag. | |
492 | size_t aligned_full_length = align_address(length + 8, addralign); | |
493 | ||
730cdc88 ILT |
494 | // Write the length of the CIE as a 32-bit word. The length word |
495 | // does not include the four bytes of the length word itself. | |
935e8877 ILT |
496 | elfcpp::Swap<32, big_endian>::writeval(oview + offset, |
497 | aligned_full_length - 4); | |
730cdc88 ILT |
498 | |
499 | // Write the tag which marks this as a CIE: a 32-bit zero. | |
500 | elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4, 0); | |
501 | ||
502 | // Write out the CIE data. | |
503 | memcpy(oview + offset + 8, this->contents_.data(), length); | |
935e8877 ILT |
504 | |
505 | if (aligned_full_length > length + 8) | |
506 | memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8)); | |
507 | ||
508 | offset += aligned_full_length; | |
730cdc88 ILT |
509 | |
510 | // Write out the associated FDEs. | |
511 | unsigned char fde_encoding = this->fde_encoding_; | |
512 | for (std::vector<Fde*>::const_iterator p = this->fdes_.begin(); | |
513 | p != this->fdes_.end(); | |
514 | ++p) | |
9d5781f8 AM |
515 | { |
516 | if ((*p)->post_map()) | |
4bead2d5 | 517 | post_fdes->push_back(Post_fde(*p, cie_offset, fde_encoding)); |
9d5781f8 | 518 | else |
9860cbcf CC |
519 | offset = (*p)->write<size, big_endian>(oview, output_offset, offset, |
520 | address, addralign, cie_offset, | |
9d5781f8 AM |
521 | fde_encoding, eh_frame_hdr); |
522 | } | |
730cdc88 ILT |
523 | |
524 | return offset; | |
525 | } | |
526 | ||
527 | // We track all the CIEs we see, and merge them when possible. This | |
528 | // works because each FDE holds an offset to the relevant CIE: we | |
529 | // rewrite the FDEs to point to the merged CIE. This is worthwhile | |
530 | // because in a typical C++ program many FDEs in many different object | |
531 | // files will use the same CIE. | |
532 | ||
533 | // An equality operator for Cie. | |
534 | ||
535 | bool | |
536 | operator==(const Cie& cie1, const Cie& cie2) | |
537 | { | |
538 | return (cie1.personality_name_ == cie2.personality_name_ | |
539 | && cie1.contents_ == cie2.contents_); | |
540 | } | |
541 | ||
542 | // A less-than operator for Cie. | |
543 | ||
544 | bool | |
545 | operator<(const Cie& cie1, const Cie& cie2) | |
546 | { | |
547 | if (cie1.personality_name_ != cie2.personality_name_) | |
548 | return cie1.personality_name_ < cie2.personality_name_; | |
549 | return cie1.contents_ < cie2.contents_; | |
550 | } | |
551 | ||
552 | // Class Eh_frame. | |
553 | ||
554 | Eh_frame::Eh_frame() | |
555 | : Output_section_data(Output_data::default_alignment()), | |
556 | eh_frame_hdr_(NULL), | |
557 | cie_offsets_(), | |
558 | unmergeable_cie_offsets_(), | |
1d6531cf ILT |
559 | mappings_are_done_(false), |
560 | final_data_size_(0) | |
730cdc88 ILT |
561 | { |
562 | } | |
563 | ||
564 | // Skip an LEB128, updating *PP to point to the next character. | |
565 | // Return false if we ran off the end of the string. | |
566 | ||
567 | bool | |
568 | Eh_frame::skip_leb128(const unsigned char** pp, const unsigned char* pend) | |
569 | { | |
570 | const unsigned char* p; | |
571 | for (p = *pp; p < pend; ++p) | |
572 | { | |
573 | if ((*p & 0x80) == 0) | |
574 | { | |
575 | *pp = p + 1; | |
576 | return true; | |
577 | } | |
578 | } | |
579 | return false; | |
580 | } | |
581 | ||
582 | // Add input section SHNDX in OBJECT to an exception frame section. | |
583 | // SYMBOLS is the contents of the symbol table section (size | |
584 | // SYMBOLS_SIZE), SYMBOL_NAMES is the symbol names section (size | |
585 | // SYMBOL_NAMES_SIZE). RELOC_SHNDX is the index of a relocation | |
586 | // section applying to SHNDX, or 0 if none, or -1U if more than one. | |
587 | // RELOC_TYPE is the type of the reloc section if there is one, either | |
588 | // SHT_REL or SHT_RELA. We try to parse the input exception frame | |
589 | // data into our data structures. If we can't do it, we return false | |
590 | // to mean that the section should be handled as a normal input | |
591 | // section. | |
592 | ||
593 | template<int size, bool big_endian> | |
e1663197 | 594 | Eh_frame::Eh_frame_section_disposition |
730cdc88 | 595 | Eh_frame::add_ehframe_input_section( |
6fa2a40b | 596 | Sized_relobj_file<size, big_endian>* object, |
730cdc88 | 597 | const unsigned char* symbols, |
8383303e | 598 | section_size_type symbols_size, |
730cdc88 | 599 | const unsigned char* symbol_names, |
8383303e | 600 | section_size_type symbol_names_size, |
730cdc88 ILT |
601 | unsigned int shndx, |
602 | unsigned int reloc_shndx, | |
603 | unsigned int reloc_type) | |
604 | { | |
605 | // Get the section contents. | |
8383303e | 606 | section_size_type contents_len; |
730cdc88 ILT |
607 | const unsigned char* pcontents = object->section_contents(shndx, |
608 | &contents_len, | |
609 | false); | |
610 | if (contents_len == 0) | |
e1663197 | 611 | return EH_EMPTY_SECTION; |
730cdc88 ILT |
612 | |
613 | // If this is the marker section for the end of the data, then | |
614 | // return false to force it to be handled as an ordinary input | |
615 | // section. If we don't do this, we won't correctly handle the case | |
616 | // of unrecognized .eh_frame sections. | |
617 | if (contents_len == 4 | |
618 | && elfcpp::Swap<32, big_endian>::readval(pcontents) == 0) | |
e1663197 | 619 | return EH_END_MARKER_SECTION; |
730cdc88 ILT |
620 | |
621 | New_cies new_cies; | |
622 | if (!this->do_add_ehframe_input_section(object, symbols, symbols_size, | |
623 | symbol_names, symbol_names_size, | |
624 | shndx, reloc_shndx, | |
625 | reloc_type, pcontents, | |
626 | contents_len, &new_cies)) | |
627 | { | |
5edd166e ILT |
628 | if (this->eh_frame_hdr_ != NULL) |
629 | this->eh_frame_hdr_->found_unrecognized_eh_frame_section(); | |
730cdc88 ILT |
630 | |
631 | for (New_cies::iterator p = new_cies.begin(); | |
632 | p != new_cies.end(); | |
633 | ++p) | |
634 | delete p->first; | |
635 | ||
e1663197 | 636 | return EH_UNRECOGNIZED_SECTION; |
730cdc88 ILT |
637 | } |
638 | ||
639 | // Now that we know we are using this section, record any new CIEs | |
640 | // that we found. | |
641 | for (New_cies::const_iterator p = new_cies.begin(); | |
642 | p != new_cies.end(); | |
643 | ++p) | |
644 | { | |
730cdc88 | 645 | if (p->second) |
1cac254c | 646 | this->cie_offsets_.insert(p->first); |
730cdc88 | 647 | else |
1cac254c | 648 | this->unmergeable_cie_offsets_.push_back(p->first); |
730cdc88 ILT |
649 | } |
650 | ||
e1663197 | 651 | return EH_OPTIMIZABLE_SECTION; |
730cdc88 ILT |
652 | } |
653 | ||
654 | // The bulk of the implementation of add_ehframe_input_section. | |
655 | ||
656 | template<int size, bool big_endian> | |
657 | bool | |
658 | Eh_frame::do_add_ehframe_input_section( | |
6fa2a40b | 659 | Sized_relobj_file<size, big_endian>* object, |
730cdc88 | 660 | const unsigned char* symbols, |
8383303e | 661 | section_size_type symbols_size, |
730cdc88 | 662 | const unsigned char* symbol_names, |
8383303e | 663 | section_size_type symbol_names_size, |
730cdc88 ILT |
664 | unsigned int shndx, |
665 | unsigned int reloc_shndx, | |
666 | unsigned int reloc_type, | |
667 | const unsigned char* pcontents, | |
8383303e | 668 | section_size_type contents_len, |
730cdc88 ILT |
669 | New_cies* new_cies) |
670 | { | |
730cdc88 ILT |
671 | Track_relocs<size, big_endian> relocs; |
672 | ||
673 | const unsigned char* p = pcontents; | |
674 | const unsigned char* pend = p + contents_len; | |
675 | ||
676 | // Get the contents of the reloc section if any. | |
677 | if (!relocs.initialize(object, reloc_shndx, reloc_type)) | |
678 | return false; | |
679 | ||
680 | // Keep track of which CIEs are at which offsets. | |
681 | Offsets_to_cie cies; | |
682 | ||
683 | while (p < pend) | |
684 | { | |
685 | if (pend - p < 4) | |
686 | return false; | |
687 | ||
688 | // There shouldn't be any relocations here. | |
689 | if (relocs.advance(p + 4 - pcontents) > 0) | |
690 | return false; | |
691 | ||
692 | unsigned int len = elfcpp::Swap<32, big_endian>::readval(p); | |
693 | p += 4; | |
694 | if (len == 0) | |
695 | { | |
696 | // We should only find a zero-length entry at the end of the | |
697 | // section. | |
698 | if (p < pend) | |
699 | return false; | |
700 | break; | |
701 | } | |
702 | // We don't support a 64-bit .eh_frame. | |
703 | if (len == 0xffffffff) | |
704 | return false; | |
705 | if (static_cast<unsigned int>(pend - p) < len) | |
706 | return false; | |
707 | ||
708 | const unsigned char* const pentend = p + len; | |
709 | ||
710 | if (pend - p < 4) | |
711 | return false; | |
712 | if (relocs.advance(p + 4 - pcontents) > 0) | |
713 | return false; | |
714 | ||
715 | unsigned int id = elfcpp::Swap<32, big_endian>::readval(p); | |
716 | p += 4; | |
717 | ||
718 | if (id == 0) | |
719 | { | |
720 | // CIE. | |
721 | if (!this->read_cie(object, shndx, symbols, symbols_size, | |
722 | symbol_names, symbol_names_size, | |
723 | pcontents, p, pentend, &relocs, &cies, | |
724 | new_cies)) | |
725 | return false; | |
726 | } | |
727 | else | |
728 | { | |
729 | // FDE. | |
730 | if (!this->read_fde(object, shndx, symbols, symbols_size, | |
731 | pcontents, id, p, pentend, &relocs, &cies)) | |
732 | return false; | |
733 | } | |
734 | ||
735 | p = pentend; | |
736 | } | |
737 | ||
738 | return true; | |
739 | } | |
740 | ||
741 | // Read a CIE. Return false if we can't parse the information. | |
742 | ||
743 | template<int size, bool big_endian> | |
744 | bool | |
6fa2a40b | 745 | Eh_frame::read_cie(Sized_relobj_file<size, big_endian>* object, |
730cdc88 ILT |
746 | unsigned int shndx, |
747 | const unsigned char* symbols, | |
8383303e | 748 | section_size_type symbols_size, |
730cdc88 | 749 | const unsigned char* symbol_names, |
8383303e | 750 | section_size_type symbol_names_size, |
730cdc88 ILT |
751 | const unsigned char* pcontents, |
752 | const unsigned char* pcie, | |
ca09d69a | 753 | const unsigned char* pcieend, |
730cdc88 ILT |
754 | Track_relocs<size, big_endian>* relocs, |
755 | Offsets_to_cie* cies, | |
756 | New_cies* new_cies) | |
757 | { | |
758 | bool mergeable = true; | |
759 | ||
760 | // We need to find the personality routine if there is one, since we | |
761 | // can only merge CIEs which use the same routine. We also need to | |
762 | // find the FDE encoding if there is one, so that we can read the PC | |
763 | // from the FDE. | |
764 | ||
765 | const unsigned char* p = pcie; | |
766 | ||
767 | if (pcieend - p < 1) | |
768 | return false; | |
769 | unsigned char version = *p++; | |
770 | if (version != 1 && version != 3) | |
771 | return false; | |
772 | ||
773 | const unsigned char* paug = p; | |
774 | const void* paugendv = memchr(p, '\0', pcieend - p); | |
775 | const unsigned char* paugend = static_cast<const unsigned char*>(paugendv); | |
776 | if (paugend == NULL) | |
777 | return false; | |
778 | p = paugend + 1; | |
779 | ||
780 | if (paug[0] == 'e' && paug[1] == 'h') | |
781 | { | |
782 | // This is a CIE from gcc before version 3.0. We can't merge | |
783 | // these. We can still read the FDEs. | |
784 | mergeable = false; | |
785 | paug += 2; | |
786 | if (*paug != '\0') | |
787 | return false; | |
788 | if (pcieend - p < size / 8) | |
789 | return false; | |
790 | p += size / 8; | |
791 | } | |
792 | ||
793 | // Skip the code alignment. | |
794 | if (!skip_leb128(&p, pcieend)) | |
795 | return false; | |
796 | ||
797 | // Skip the data alignment. | |
798 | if (!skip_leb128(&p, pcieend)) | |
799 | return false; | |
800 | ||
801 | // Skip the return column. | |
802 | if (version == 1) | |
803 | { | |
804 | if (pcieend - p < 1) | |
805 | return false; | |
806 | ++p; | |
807 | } | |
808 | else | |
809 | { | |
810 | if (!skip_leb128(&p, pcieend)) | |
811 | return false; | |
812 | } | |
813 | ||
814 | if (*paug == 'z') | |
815 | { | |
816 | ++paug; | |
817 | // Skip the augmentation size. | |
818 | if (!skip_leb128(&p, pcieend)) | |
819 | return false; | |
820 | } | |
821 | ||
822 | unsigned char fde_encoding = elfcpp::DW_EH_PE_absptr; | |
823 | int per_offset = -1; | |
824 | while (*paug != '\0') | |
825 | { | |
826 | switch (*paug) | |
827 | { | |
828 | case 'L': // LSDA encoding. | |
829 | if (pcieend - p < 1) | |
830 | return false; | |
831 | ++p; | |
832 | break; | |
833 | ||
834 | case 'R': // FDE encoding. | |
835 | if (pcieend - p < 1) | |
836 | return false; | |
837 | fde_encoding = *p; | |
838 | switch (fde_encoding & 7) | |
839 | { | |
840 | case elfcpp::DW_EH_PE_absptr: | |
841 | case elfcpp::DW_EH_PE_udata2: | |
842 | case elfcpp::DW_EH_PE_udata4: | |
843 | case elfcpp::DW_EH_PE_udata8: | |
844 | break; | |
845 | default: | |
4117d768 ILT |
846 | // We don't expect to see any other cases here, and |
847 | // we're not prepared to handle them. | |
730cdc88 ILT |
848 | return false; |
849 | } | |
850 | ++p; | |
851 | break; | |
852 | ||
853 | case 'S': | |
854 | break; | |
855 | ||
856 | case 'P': | |
857 | // Personality encoding. | |
858 | { | |
859 | if (pcieend - p < 1) | |
860 | return false; | |
861 | unsigned char per_encoding = *p; | |
862 | ++p; | |
863 | ||
864 | if ((per_encoding & 0x60) == 0x60) | |
865 | return false; | |
866 | unsigned int per_width; | |
867 | switch (per_encoding & 7) | |
868 | { | |
869 | case elfcpp::DW_EH_PE_udata2: | |
870 | per_width = 2; | |
871 | break; | |
872 | case elfcpp::DW_EH_PE_udata4: | |
873 | per_width = 4; | |
874 | break; | |
875 | case elfcpp::DW_EH_PE_udata8: | |
876 | per_width = 8; | |
877 | break; | |
878 | case elfcpp::DW_EH_PE_absptr: | |
879 | per_width = size / 8; | |
880 | break; | |
881 | default: | |
882 | return false; | |
883 | } | |
884 | ||
885 | if ((per_encoding & 0xf0) == elfcpp::DW_EH_PE_aligned) | |
886 | { | |
887 | unsigned int len = p - pcie; | |
888 | len += per_width - 1; | |
889 | len &= ~ (per_width - 1); | |
890 | if (static_cast<unsigned int>(pcieend - p) < len) | |
891 | return false; | |
892 | p += len; | |
893 | } | |
894 | ||
895 | per_offset = p - pcontents; | |
896 | ||
897 | if (static_cast<unsigned int>(pcieend - p) < per_width) | |
898 | return false; | |
899 | p += per_width; | |
900 | } | |
901 | break; | |
902 | ||
903 | default: | |
904 | return false; | |
905 | } | |
906 | ||
907 | ++paug; | |
908 | } | |
909 | ||
910 | const char* personality_name = ""; | |
911 | if (per_offset != -1) | |
912 | { | |
913 | if (relocs->advance(per_offset) > 0) | |
914 | return false; | |
915 | if (relocs->next_offset() != per_offset) | |
916 | return false; | |
917 | ||
918 | unsigned int personality_symndx = relocs->next_symndx(); | |
919 | if (personality_symndx == -1U) | |
920 | return false; | |
921 | ||
922 | if (personality_symndx < object->local_symbol_count()) | |
923 | { | |
924 | // We can only merge this CIE if the personality routine is | |
925 | // a global symbol. We can still read the FDEs. | |
926 | mergeable = false; | |
927 | } | |
928 | else | |
929 | { | |
930 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
931 | if (personality_symndx >= symbols_size / sym_size) | |
932 | return false; | |
933 | elfcpp::Sym<size, big_endian> sym(symbols | |
934 | + (personality_symndx * sym_size)); | |
935 | unsigned int name_offset = sym.get_st_name(); | |
936 | if (name_offset >= symbol_names_size) | |
937 | return false; | |
938 | personality_name = (reinterpret_cast<const char*>(symbol_names) | |
939 | + name_offset); | |
940 | } | |
941 | ||
942 | int r = relocs->advance(per_offset + 1); | |
943 | gold_assert(r == 1); | |
944 | } | |
945 | ||
946 | if (relocs->advance(pcieend - pcontents) > 0) | |
947 | return false; | |
948 | ||
949 | Cie cie(object, shndx, (pcie - 8) - pcontents, fde_encoding, | |
950 | personality_name, pcie, pcieend - pcie); | |
951 | Cie* cie_pointer = NULL; | |
952 | if (mergeable) | |
953 | { | |
954 | Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie); | |
955 | if (find_cie != this->cie_offsets_.end()) | |
1cac254c | 956 | cie_pointer = *find_cie; |
730cdc88 ILT |
957 | else |
958 | { | |
959 | // See if we already saw this CIE in this object file. | |
960 | for (New_cies::const_iterator pc = new_cies->begin(); | |
961 | pc != new_cies->end(); | |
962 | ++pc) | |
963 | { | |
964 | if (*(pc->first) == cie) | |
965 | { | |
966 | cie_pointer = pc->first; | |
967 | break; | |
968 | } | |
969 | } | |
970 | } | |
971 | } | |
972 | ||
973 | if (cie_pointer == NULL) | |
974 | { | |
975 | cie_pointer = new Cie(cie); | |
976 | new_cies->push_back(std::make_pair(cie_pointer, mergeable)); | |
977 | } | |
978 | else | |
979 | { | |
980 | // We are deleting this CIE. Record that in our mapping from | |
981 | // input sections to the output section. At this point we don't | |
982 | // know for sure that we are doing a special mapping for this | |
983 | // input section, but that's OK--if we don't do a special | |
984 | // mapping, nobody will ever ask for the mapping we add here. | |
dbe40a88 RÁE |
985 | object->add_merge_mapping(this, shndx, (pcie - 8) - pcontents, |
986 | pcieend - (pcie - 8), -1); | |
730cdc88 ILT |
987 | } |
988 | ||
989 | // Record this CIE plus the offset in the input section. | |
990 | cies->insert(std::make_pair(pcie - pcontents, cie_pointer)); | |
991 | ||
992 | return true; | |
993 | } | |
994 | ||
995 | // Read an FDE. Return false if we can't parse the information. | |
996 | ||
997 | template<int size, bool big_endian> | |
998 | bool | |
6fa2a40b | 999 | Eh_frame::read_fde(Sized_relobj_file<size, big_endian>* object, |
730cdc88 ILT |
1000 | unsigned int shndx, |
1001 | const unsigned char* symbols, | |
8383303e | 1002 | section_size_type symbols_size, |
730cdc88 | 1003 | const unsigned char* pcontents, |
2ea97941 | 1004 | unsigned int offset, |
730cdc88 | 1005 | const unsigned char* pfde, |
ca09d69a | 1006 | const unsigned char* pfdeend, |
730cdc88 ILT |
1007 | Track_relocs<size, big_endian>* relocs, |
1008 | Offsets_to_cie* cies) | |
1009 | { | |
2ea97941 | 1010 | // OFFSET is the distance between the 4 bytes before PFDE to the |
730cdc88 ILT |
1011 | // start of the CIE. The offset we recorded for the CIE is 8 bytes |
1012 | // after the start of the CIE--after the length and the zero tag. | |
2ea97941 | 1013 | unsigned int cie_offset = (pfde - 4 - pcontents) - offset + 8; |
730cdc88 ILT |
1014 | Offsets_to_cie::const_iterator pcie = cies->find(cie_offset); |
1015 | if (pcie == cies->end()) | |
1016 | return false; | |
1017 | Cie* cie = pcie->second; | |
1018 | ||
698400bf CC |
1019 | int pc_size = 0; |
1020 | switch (cie->fde_encoding() & 7) | |
1021 | { | |
1022 | case elfcpp::DW_EH_PE_udata2: | |
1023 | pc_size = 2; | |
1024 | break; | |
1025 | case elfcpp::DW_EH_PE_udata4: | |
1026 | pc_size = 4; | |
1027 | break; | |
1028 | case elfcpp::DW_EH_PE_udata8: | |
1029 | gold_assert(size == 64); | |
1030 | pc_size = 8; | |
1031 | break; | |
1032 | case elfcpp::DW_EH_PE_absptr: | |
1033 | pc_size = size == 32 ? 4 : 8; | |
1034 | break; | |
1035 | default: | |
1036 | // All other cases were rejected in Eh_frame::read_cie. | |
1037 | gold_unreachable(); | |
1038 | } | |
1039 | ||
730cdc88 ILT |
1040 | // The FDE should start with a reloc to the start of the code which |
1041 | // it describes. | |
1042 | if (relocs->advance(pfde - pcontents) > 0) | |
1043 | return false; | |
730cdc88 | 1044 | if (relocs->next_offset() != pfde - pcontents) |
698400bf CC |
1045 | { |
1046 | // In an object produced by a relocatable link, gold may have | |
1047 | // discarded a COMDAT group in the previous link, but not the | |
1048 | // corresponding FDEs. In that case, gold will have discarded | |
1049 | // the relocations, so the FDE will have a non-relocatable zero | |
1050 | // (regardless of whether the PC encoding is absolute, pc-relative, | |
1051 | // or data-relative) instead of a pointer to the start of the code. | |
1052 | ||
1053 | uint64_t pc_value = 0; | |
1054 | switch (pc_size) | |
1055 | { | |
1056 | case 2: | |
1057 | pc_value = elfcpp::Swap<16, big_endian>::readval(pfde); | |
1058 | break; | |
1059 | case 4: | |
1060 | pc_value = elfcpp::Swap<32, big_endian>::readval(pfde); | |
1061 | break; | |
1062 | case 8: | |
1063 | pc_value = elfcpp::Swap_unaligned<64, big_endian>::readval(pfde); | |
1064 | break; | |
1065 | default: | |
1066 | gold_unreachable(); | |
1067 | } | |
1068 | ||
1069 | if (pc_value == 0) | |
1070 | { | |
1071 | // This FDE applies to a discarded function. We | |
1072 | // can discard this FDE. | |
1073 | object->add_merge_mapping(this, shndx, (pfde - 8) - pcontents, | |
1074 | pfdeend - (pfde - 8), -1); | |
1075 | return true; | |
1076 | } | |
1077 | ||
1078 | // Otherwise, reject the FDE. | |
1079 | return false; | |
1080 | } | |
730cdc88 ILT |
1081 | |
1082 | unsigned int symndx = relocs->next_symndx(); | |
1083 | if (symndx == -1U) | |
1084 | return false; | |
1085 | ||
1086 | // There can be another reloc in the FDE, if the CIE specifies an | |
1087 | // LSDA (language specific data area). We currently don't care. We | |
1088 | // will care later if we want to optimize the LSDA from an absolute | |
1089 | // pointer to a PC relative offset when generating a shared library. | |
1090 | relocs->advance(pfdeend - pcontents); | |
1091 | ||
fc5a9bd5 CC |
1092 | // Find the section index for code that this FDE describes. |
1093 | // If we have discarded the section, we can also discard the FDE. | |
730cdc88 ILT |
1094 | unsigned int fde_shndx; |
1095 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
1096 | if (symndx >= symbols_size / sym_size) | |
1097 | return false; | |
1098 | elfcpp::Sym<size, big_endian> sym(symbols + symndx * sym_size); | |
d491d34e ILT |
1099 | bool is_ordinary; |
1100 | fde_shndx = object->adjust_sym_shndx(symndx, sym.get_st_shndx(), | |
1101 | &is_ordinary); | |
fc5a9bd5 CC |
1102 | bool is_discarded = (is_ordinary |
1103 | && fde_shndx != elfcpp::SHN_UNDEF | |
1104 | && fde_shndx < object->shnum() | |
1105 | && !object->is_section_included(fde_shndx)); | |
1106 | ||
1107 | // Fetch the address range field from the FDE. The offset and size | |
1108 | // of the field depends on the PC encoding given in the CIE, but | |
1109 | // it is always an absolute value. If the address range is 0, this | |
1110 | // FDE corresponds to a function that was discarded during optimization | |
1111 | // (too late to discard the corresponding FDE). | |
1112 | uint64_t address_range = 0; | |
fc5a9bd5 CC |
1113 | switch (pc_size) |
1114 | { | |
698400bf | 1115 | case 2: |
fc5a9bd5 CC |
1116 | address_range = elfcpp::Swap<16, big_endian>::readval(pfde + 2); |
1117 | break; | |
698400bf | 1118 | case 4: |
fc5a9bd5 CC |
1119 | address_range = elfcpp::Swap<32, big_endian>::readval(pfde + 4); |
1120 | break; | |
698400bf | 1121 | case 8: |
fc5a9bd5 CC |
1122 | address_range = elfcpp::Swap_unaligned<64, big_endian>::readval(pfde + 8); |
1123 | break; | |
1124 | default: | |
fc5a9bd5 CC |
1125 | gold_unreachable(); |
1126 | } | |
730cdc88 | 1127 | |
fc5a9bd5 | 1128 | if (is_discarded || address_range == 0) |
730cdc88 | 1129 | { |
fc5a9bd5 | 1130 | // This FDE applies to a discarded function. We |
730cdc88 | 1131 | // can discard this FDE. |
dbe40a88 RÁE |
1132 | object->add_merge_mapping(this, shndx, (pfde - 8) - pcontents, |
1133 | pfdeend - (pfde - 8), -1); | |
730cdc88 ILT |
1134 | return true; |
1135 | } | |
1136 | ||
1137 | cie->add_fde(new Fde(object, shndx, (pfde - 8) - pcontents, | |
1138 | pfde, pfdeend - pfde)); | |
1139 | ||
1140 | return true; | |
1141 | } | |
1142 | ||
07a60597 ILT |
1143 | // Add unwind information for a PLT. |
1144 | ||
1145 | void | |
1146 | Eh_frame::add_ehframe_for_plt(Output_data* plt, const unsigned char* cie_data, | |
1147 | size_t cie_length, const unsigned char* fde_data, | |
1148 | size_t fde_length) | |
1149 | { | |
1150 | Cie cie(NULL, 0, 0, elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4, "", | |
1151 | cie_data, cie_length); | |
1152 | Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie); | |
1153 | Cie* pcie; | |
1154 | if (find_cie != this->cie_offsets_.end()) | |
1155 | pcie = *find_cie; | |
1156 | else | |
1157 | { | |
9d5781f8 | 1158 | gold_assert(!this->mappings_are_done_); |
07a60597 ILT |
1159 | pcie = new Cie(cie); |
1160 | this->cie_offsets_.insert(pcie); | |
1161 | } | |
1162 | ||
9d5781f8 | 1163 | Fde* fde = new Fde(plt, fde_data, fde_length, this->mappings_are_done_); |
07a60597 | 1164 | pcie->add_fde(fde); |
9d5781f8 AM |
1165 | |
1166 | if (this->mappings_are_done_) | |
1167 | this->final_data_size_ += align_address(fde_length + 8, this->addralign()); | |
07a60597 ILT |
1168 | } |
1169 | ||
be897fb7 AM |
1170 | // Remove unwind information for a PLT. Only the last FDE added may be removed. |
1171 | ||
1172 | void | |
1173 | Eh_frame::remove_ehframe_for_plt(Output_data* plt, | |
1174 | const unsigned char* cie_data, | |
1175 | size_t cie_length, | |
1176 | const unsigned char* fde_data, | |
1177 | size_t fde_length) | |
1178 | { | |
1179 | Cie cie(NULL, 0, 0, elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4, "", | |
1180 | cie_data, cie_length); | |
1181 | Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie); | |
1182 | gold_assert (find_cie != this->cie_offsets_.end()); | |
1183 | Cie* pcie = *find_cie; | |
1184 | ||
1185 | Fde* fde = new Fde(plt, fde_data, fde_length, this->mappings_are_done_); | |
1186 | pcie->remove_fde(fde); | |
1187 | ||
1188 | if (this->mappings_are_done_) | |
1189 | this->final_data_size_ -= align_address(fde_length + 8, this->addralign()); | |
1190 | } | |
1191 | ||
730cdc88 ILT |
1192 | // Return the number of FDEs. |
1193 | ||
1194 | unsigned int | |
1195 | Eh_frame::fde_count() const | |
1196 | { | |
1197 | unsigned int ret = 0; | |
1198 | for (Unmergeable_cie_offsets::const_iterator p = | |
1199 | this->unmergeable_cie_offsets_.begin(); | |
1200 | p != this->unmergeable_cie_offsets_.end(); | |
1201 | ++p) | |
1cac254c | 1202 | ret += (*p)->fde_count(); |
730cdc88 ILT |
1203 | for (Cie_offsets::const_iterator p = this->cie_offsets_.begin(); |
1204 | p != this->cie_offsets_.end(); | |
1205 | ++p) | |
1cac254c | 1206 | ret += (*p)->fde_count(); |
730cdc88 ILT |
1207 | return ret; |
1208 | } | |
1209 | ||
1210 | // Set the final data size. | |
1211 | ||
1212 | void | |
27bc2bce | 1213 | Eh_frame::set_final_data_size() |
730cdc88 | 1214 | { |
1d6531cf ILT |
1215 | // We can be called more than once if Layout::set_segment_offsets |
1216 | // finds a better mapping. We don't want to add all the mappings | |
1217 | // again. | |
1218 | if (this->mappings_are_done_) | |
1219 | { | |
1220 | this->set_data_size(this->final_data_size_); | |
1221 | return; | |
1222 | } | |
1223 | ||
9860cbcf CC |
1224 | section_offset_type output_start = 0; |
1225 | if (this->is_offset_valid()) | |
1226 | output_start = this->offset() - this->output_section()->offset(); | |
1227 | section_offset_type output_offset = output_start; | |
730cdc88 ILT |
1228 | |
1229 | for (Unmergeable_cie_offsets::iterator p = | |
1230 | this->unmergeable_cie_offsets_.begin(); | |
1231 | p != this->unmergeable_cie_offsets_.end(); | |
1232 | ++p) | |
2ea97941 ILT |
1233 | output_offset = (*p)->set_output_offset(output_offset, |
1234 | this->addralign(), | |
dbe40a88 | 1235 | this); |
730cdc88 ILT |
1236 | |
1237 | for (Cie_offsets::iterator p = this->cie_offsets_.begin(); | |
1238 | p != this->cie_offsets_.end(); | |
1239 | ++p) | |
2ea97941 ILT |
1240 | output_offset = (*p)->set_output_offset(output_offset, |
1241 | this->addralign(), | |
dbe40a88 | 1242 | this); |
730cdc88 | 1243 | |
1d6531cf | 1244 | this->mappings_are_done_ = true; |
9860cbcf | 1245 | this->final_data_size_ = output_offset - output_start; |
1d6531cf | 1246 | |
2ea97941 | 1247 | gold_assert((output_offset & (this->addralign() - 1)) == 0); |
9860cbcf | 1248 | this->set_data_size(this->final_data_size_); |
730cdc88 ILT |
1249 | } |
1250 | ||
1251 | // Return an output offset for an input offset. | |
1252 | ||
1253 | bool | |
1254 | Eh_frame::do_output_offset(const Relobj* object, unsigned int shndx, | |
2ea97941 | 1255 | section_offset_type offset, |
8383303e | 1256 | section_offset_type* poutput) const |
730cdc88 | 1257 | { |
dbe40a88 | 1258 | return object->merge_output_offset(shndx, offset, poutput); |
a9a60db6 ILT |
1259 | } |
1260 | ||
730cdc88 ILT |
1261 | // Write the data to the output file. |
1262 | ||
1263 | void | |
1264 | Eh_frame::do_write(Output_file* of) | |
1265 | { | |
2ea97941 | 1266 | const off_t offset = this->offset(); |
730cdc88 | 1267 | const off_t oview_size = this->data_size(); |
2ea97941 | 1268 | unsigned char* const oview = of->get_output_view(offset, oview_size); |
730cdc88 | 1269 | |
8851ecca | 1270 | switch (parameters->size_and_endianness()) |
730cdc88 | 1271 | { |
730cdc88 | 1272 | #ifdef HAVE_TARGET_32_LITTLE |
8851ecca ILT |
1273 | case Parameters::TARGET_32_LITTLE: |
1274 | this->do_sized_write<32, false>(oview); | |
1275 | break; | |
730cdc88 | 1276 | #endif |
730cdc88 | 1277 | #ifdef HAVE_TARGET_32_BIG |
8851ecca ILT |
1278 | case Parameters::TARGET_32_BIG: |
1279 | this->do_sized_write<32, true>(oview); | |
1280 | break; | |
730cdc88 | 1281 | #endif |
730cdc88 | 1282 | #ifdef HAVE_TARGET_64_LITTLE |
8851ecca ILT |
1283 | case Parameters::TARGET_64_LITTLE: |
1284 | this->do_sized_write<64, false>(oview); | |
1285 | break; | |
730cdc88 | 1286 | #endif |
730cdc88 | 1287 | #ifdef HAVE_TARGET_64_BIG |
8851ecca ILT |
1288 | case Parameters::TARGET_64_BIG: |
1289 | this->do_sized_write<64, true>(oview); | |
1290 | break; | |
730cdc88 | 1291 | #endif |
8851ecca ILT |
1292 | default: |
1293 | gold_unreachable(); | |
730cdc88 | 1294 | } |
730cdc88 | 1295 | |
2ea97941 | 1296 | of->write_output_view(offset, oview_size, oview); |
730cdc88 ILT |
1297 | } |
1298 | ||
1299 | // Write the data to the output file--template version. | |
1300 | ||
1301 | template<int size, bool big_endian> | |
1302 | void | |
1303 | Eh_frame::do_sized_write(unsigned char* oview) | |
1304 | { | |
07a60597 | 1305 | uint64_t address = this->address(); |
2ea97941 | 1306 | unsigned int addralign = this->addralign(); |
8383303e | 1307 | section_offset_type o = 0; |
9860cbcf | 1308 | const off_t output_offset = this->offset() - this->output_section()->offset(); |
9d5781f8 | 1309 | Post_fdes post_fdes; |
730cdc88 ILT |
1310 | for (Unmergeable_cie_offsets::iterator p = |
1311 | this->unmergeable_cie_offsets_.begin(); | |
1312 | p != this->unmergeable_cie_offsets_.end(); | |
1313 | ++p) | |
9860cbcf CC |
1314 | o = (*p)->write<size, big_endian>(oview, output_offset, o, address, |
1315 | addralign, this->eh_frame_hdr_, | |
1316 | &post_fdes); | |
730cdc88 ILT |
1317 | for (Cie_offsets::iterator p = this->cie_offsets_.begin(); |
1318 | p != this->cie_offsets_.end(); | |
1319 | ++p) | |
9860cbcf CC |
1320 | o = (*p)->write<size, big_endian>(oview, output_offset, o, address, |
1321 | addralign, this->eh_frame_hdr_, | |
1322 | &post_fdes); | |
9d5781f8 AM |
1323 | for (Post_fdes::iterator p = post_fdes.begin(); |
1324 | p != post_fdes.end(); | |
1325 | ++p) | |
9860cbcf CC |
1326 | o = (*p).fde->write<size, big_endian>(oview, output_offset, o, address, |
1327 | addralign, (*p).cie_offset, | |
4bead2d5 AM |
1328 | (*p).fde_encoding, |
1329 | this->eh_frame_hdr_); | |
730cdc88 ILT |
1330 | } |
1331 | ||
1332 | #ifdef HAVE_TARGET_32_LITTLE | |
1333 | template | |
e1663197 | 1334 | Eh_frame::Eh_frame_section_disposition |
730cdc88 | 1335 | Eh_frame::add_ehframe_input_section<32, false>( |
6fa2a40b | 1336 | Sized_relobj_file<32, false>* object, |
730cdc88 | 1337 | const unsigned char* symbols, |
8383303e | 1338 | section_size_type symbols_size, |
730cdc88 | 1339 | const unsigned char* symbol_names, |
8383303e | 1340 | section_size_type symbol_names_size, |
730cdc88 ILT |
1341 | unsigned int shndx, |
1342 | unsigned int reloc_shndx, | |
1343 | unsigned int reloc_type); | |
1344 | #endif | |
1345 | ||
1346 | #ifdef HAVE_TARGET_32_BIG | |
1347 | template | |
e1663197 | 1348 | Eh_frame::Eh_frame_section_disposition |
730cdc88 | 1349 | Eh_frame::add_ehframe_input_section<32, true>( |
6fa2a40b | 1350 | Sized_relobj_file<32, true>* object, |
730cdc88 | 1351 | const unsigned char* symbols, |
8383303e | 1352 | section_size_type symbols_size, |
730cdc88 | 1353 | const unsigned char* symbol_names, |
8383303e | 1354 | section_size_type symbol_names_size, |
730cdc88 ILT |
1355 | unsigned int shndx, |
1356 | unsigned int reloc_shndx, | |
1357 | unsigned int reloc_type); | |
1358 | #endif | |
1359 | ||
1360 | #ifdef HAVE_TARGET_64_LITTLE | |
1361 | template | |
e1663197 | 1362 | Eh_frame::Eh_frame_section_disposition |
730cdc88 | 1363 | Eh_frame::add_ehframe_input_section<64, false>( |
6fa2a40b | 1364 | Sized_relobj_file<64, false>* object, |
730cdc88 | 1365 | const unsigned char* symbols, |
8383303e | 1366 | section_size_type symbols_size, |
730cdc88 | 1367 | const unsigned char* symbol_names, |
8383303e | 1368 | section_size_type symbol_names_size, |
730cdc88 ILT |
1369 | unsigned int shndx, |
1370 | unsigned int reloc_shndx, | |
1371 | unsigned int reloc_type); | |
1372 | #endif | |
1373 | ||
1374 | #ifdef HAVE_TARGET_64_BIG | |
1375 | template | |
e1663197 | 1376 | Eh_frame::Eh_frame_section_disposition |
730cdc88 | 1377 | Eh_frame::add_ehframe_input_section<64, true>( |
6fa2a40b | 1378 | Sized_relobj_file<64, true>* object, |
730cdc88 | 1379 | const unsigned char* symbols, |
8383303e | 1380 | section_size_type symbols_size, |
730cdc88 | 1381 | const unsigned char* symbol_names, |
8383303e | 1382 | section_size_type symbol_names_size, |
730cdc88 ILT |
1383 | unsigned int shndx, |
1384 | unsigned int reloc_shndx, | |
1385 | unsigned int reloc_type); | |
1386 | #endif | |
1387 | ||
3151305a | 1388 | } // End namespace gold. |