or1k: RTEMS target support and simplify matching
[deliverable/binutils-gdb.git] / gold / reduced_debug_output.cc
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1// reduced_debug_output.cc -- output reduced debugging information to save space
2
4b95cf5c 3// Copyright (C) 2008-2014 Free Software Foundation, Inc.
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4// Written by Caleb Howe <cshowe@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
25#include "parameters.h"
26#include "options.h"
27#include "dwarf.h"
28#include "dwarf_reader.h"
29#include "reduced_debug_output.h"
4f787271 30#include "int_encoding.h"
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31
32#include <vector>
33
34namespace gold
35{
36
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37// Given a pointer to the beginning of a die and the beginning of the associated
38// abbreviation fills in die_end with the end of the information entry. If
39// successful returns true. Get_die_end also takes a pointer to the end of the
40// buffer containing the die. If die_end would be beyond the end of the
41// buffer, or if an unsupported dwarf form is encountered returns false.
42bool
43Output_reduced_debug_info_section::get_die_end(
44 unsigned char* die, unsigned char* abbrev, unsigned char** die_end,
45 unsigned char* buffer_end, int address_size, bool is64)
46{
47 size_t LEB_size;
48 uint64_t LEB_decoded;
49 for(;;)
50 {
51 uint64_t attribute = read_unsigned_LEB_128(abbrev, &LEB_size);
52 abbrev += LEB_size;
53 elfcpp::DW_FORM form =
54 static_cast<elfcpp::DW_FORM>(read_unsigned_LEB_128(abbrev,
55 &LEB_size));
56 abbrev += LEB_size;
57 if (!(attribute || form))
58 break;
59 if (die >= buffer_end)
60 return false;
61 switch(form)
62 {
feb5f3b0 63 case elfcpp::DW_FORM_flag_present:
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64 break;
65 case elfcpp::DW_FORM_strp:
feb5f3b0 66 case elfcpp::DW_FORM_sec_offset:
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67 die += is64 ? 8 : 4;
68 break;
69 case elfcpp::DW_FORM_addr:
70 case elfcpp::DW_FORM_ref_addr:
71 die += address_size;
72 break;
73 case elfcpp::DW_FORM_block1:
74 die += *die;
75 die += 1;
76 break;
77 case elfcpp::DW_FORM_block2:
78 {
79 uint16_t block_size;
80 block_size = read_from_pointer<16>(&die);
81 die += block_size;
82 break;
83 }
84 case elfcpp::DW_FORM_block4:
85 {
86 uint32_t block_size;
87 block_size = read_from_pointer<32>(&die);
88 die += block_size;
89 break;
90 }
91 case elfcpp::DW_FORM_block:
feb5f3b0 92 case elfcpp::DW_FORM_exprloc:
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93 LEB_decoded = read_unsigned_LEB_128(die, &LEB_size);
94 die += (LEB_decoded + LEB_size);
95 break;
96 case elfcpp::DW_FORM_data1:
97 case elfcpp::DW_FORM_ref1:
98 case elfcpp::DW_FORM_flag:
99 die += 1;
100 break;
101 case elfcpp::DW_FORM_data2:
102 case elfcpp::DW_FORM_ref2:
103 die += 2;
104 break;
105 case elfcpp::DW_FORM_data4:
106 case elfcpp::DW_FORM_ref4:
107 die += 4;
108 break;
109 case elfcpp::DW_FORM_data8:
110 case elfcpp::DW_FORM_ref8:
feb5f3b0 111 case elfcpp::DW_FORM_ref_sig8:
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112 die += 8;
113 break;
114 case elfcpp::DW_FORM_ref_udata:
115 case elfcpp::DW_FORM_udata:
116 read_unsigned_LEB_128(die, &LEB_size);
117 die += LEB_size;
118 break;
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119 case elfcpp::DW_FORM_sdata:
120 read_signed_LEB_128(die, &LEB_size);
121 die += LEB_size;
122 break;
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123 case elfcpp::DW_FORM_string:
124 {
125 size_t length = strlen(reinterpret_cast<char*>(die));
126 die += length + 1;
127 break;
128 }
62b01cb5 129 case elfcpp::DW_FORM_indirect:
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130 case elfcpp::DW_FORM_GNU_addr_index:
131 case elfcpp::DW_FORM_GNU_str_index:
b9b9f2ee 132 default:
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133 return false;
134 }
135 }
136 *die_end = die;
137 return true;
138}
139
140void
141Output_reduced_debug_abbrev_section::set_final_data_size()
142{
143 if (this->sized_ || this->failed_)
144 return;
145
146 uint64_t abbrev_number;
147 size_t LEB_size;
148 unsigned char* abbrev_data = this->postprocessing_buffer();
149 unsigned char* abbrev_end = this->postprocessing_buffer() +
150 this->postprocessing_buffer_size();
151 this->write_to_postprocessing_buffer();
152 while(abbrev_data < abbrev_end)
153 {
154 uint64_t abbrev_offset = abbrev_data - this->postprocessing_buffer();
155 while((abbrev_number = read_unsigned_LEB_128(abbrev_data, &LEB_size)))
156 {
157 if (abbrev_data >= abbrev_end)
158 {
159 failed("Debug abbreviations extend beyond .debug_abbrev "
160 "section; failed to reduce debug abbreviations");
161 return;
162 }
163 abbrev_data += LEB_size;
164
165 // Together with the abbreviation number these fields make up
9b547ce6 166 // the header for each abbreviation.
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167 uint64_t abbrev_type = read_unsigned_LEB_128(abbrev_data, &LEB_size);
168 abbrev_data += LEB_size;
169
170 // This would ordinarily be the has_children field of the
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171 // abbreviation. But it's going to be false after reducing the
172 // information, so there's no point in storing it.
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173 abbrev_data++;
174
9b547ce6 175 // Read to the end of the current abbreviation.
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176 // This is indicated by two zero unsigned LEBs in a row. We don't
177 // need to parse the data yet, so we just scan through the data
178 // looking for two consecutive 0 bytes indicating the end of the
9b547ce6 179 // abbreviation.
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180 unsigned char* current_abbrev;
181 for (current_abbrev = abbrev_data;
182 current_abbrev[0] || current_abbrev[1];
183 current_abbrev++)
184 {
185 if (current_abbrev >= abbrev_end)
186 {
187 this->failed(_("Debug abbreviations extend beyond "
188 ".debug_abbrev section; failed to reduce "
189 "debug abbreviations"));
190 return;
191 }
192 }
193 // Account for the two nulls and advance to the start of the
194 // next abbreviation.
195 current_abbrev += 2;
196
197 // We're eliminating every entry except for compile units, so we
198 // only need to store abbreviations that describe them
199 if (abbrev_type == elfcpp::DW_TAG_compile_unit)
200 {
201 write_unsigned_LEB_128(&this->data_, ++this->abbrev_count_);
202 write_unsigned_LEB_128(&this->data_, abbrev_type);
203 // has_children is false for all entries
204 this->data_.push_back(0);
205 this->abbrev_mapping_[std::make_pair(abbrev_offset,
206 abbrev_number)] =
207 std::make_pair(abbrev_count_, this->data_.size());
208 this->data_.insert(this->data_.end(), abbrev_data,
209 current_abbrev);
210 }
211 abbrev_data = current_abbrev;
212 }
213 gold_assert(LEB_size == 1);
214 abbrev_data += LEB_size;
215 }
216 // Null terminate the list of abbreviations
217 this->data_.push_back(0);
218 this->set_data_size(data_.size());
219 this->sized_ = true;
220}
221
222void
223Output_reduced_debug_abbrev_section::do_write(Output_file* of)
224{
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225 off_t offset = this->offset();
226 off_t data_size = this->data_size();
227 unsigned char* view = of->get_output_view(offset, data_size);
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228 if (this->failed_)
229 memcpy(view, this->postprocessing_buffer(),
230 this->postprocessing_buffer_size());
231 else
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232 memcpy(view, &this->data_.front(), data_size);
233 of->write_output_view(offset, data_size, view);
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234}
235
236// Locates the abbreviation with abbreviation_number abbrev_number in the
237// abbreviation table at offset abbrev_offset. abbrev_number is updated with
238// its new abbreviation number and a pointer to the beginning of the
239// abbreviation is returned.
240unsigned char*
241Output_reduced_debug_abbrev_section::get_new_abbrev(
242 uint64_t* abbrev_number, uint64_t abbrev_offset)
243{
244 set_final_data_size();
245 std::pair<uint64_t, uint64_t> abbrev_info =
246 this->abbrev_mapping_[std::make_pair(abbrev_offset, *abbrev_number)];
247 *abbrev_number = abbrev_info.first;
248 return &this->data_[abbrev_info.second];
249}
250
251void Output_reduced_debug_info_section::set_final_data_size()
252{
253 if (this->failed_)
254 return;
255 unsigned char* debug_info = this->postprocessing_buffer();
256 unsigned char* debug_info_end = (this->postprocessing_buffer()
257 + this->postprocessing_buffer_size());
258 unsigned char* next_compile_unit;
259 this->write_to_postprocessing_buffer();
260
261 while (debug_info < debug_info_end)
262 {
263 uint32_t compile_unit_start = read_from_pointer<32>(&debug_info);
264 // The first 4 bytes of each compile unit determine whether or
265 // not we're using dwarf32 or dwarf64. This is not necessarily
266 // related to whether the binary is 32 or 64 bits.
267 if (compile_unit_start == 0xFFFFFFFF)
268 {
269 // Technically the size can be up to 96 bits. Rather than handle
270 // 96/128 bit integers we just truncate the size at 64 bits.
271 if (0 != read_from_pointer<32>(&debug_info))
272 {
273 this->failed(_("Extremely large compile unit in debug info; "
274 "failed to reduce debug info"));
275 return;
276 }
277 const int dwarf64_header_size = sizeof(uint64_t) + sizeof(uint16_t) +
278 sizeof(uint64_t) + sizeof(uint8_t);
279 if (debug_info + dwarf64_header_size >= debug_info_end)
280 {
281 this->failed(_("Debug info extends beyond .debug_info section;"
282 "failed to reduce debug info"));
283 return;
284 }
285
286 uint64_t compile_unit_size = read_from_pointer<64>(&debug_info);
287 next_compile_unit = debug_info + compile_unit_size;
288 uint16_t version = read_from_pointer<16>(&debug_info);
289 uint64_t abbrev_offset = read_from_pointer<64>(&debug_info);
290 uint8_t address_size = read_from_pointer<8>(&debug_info);
291 size_t LEB_size;
292 uint64_t abbreviation_number = read_unsigned_LEB_128(debug_info,
293 &LEB_size);
294 debug_info += LEB_size;
295 unsigned char* die_abbrev = this->associated_abbrev_->get_new_abbrev(
296 &abbreviation_number, abbrev_offset);
297 unsigned char* die_end;
298 if (!this->get_die_end(debug_info, die_abbrev, &die_end,
299 debug_info_end, address_size, true))
300 {
301 this->failed(_("Invalid DIE in debug info; "
302 "failed to reduce debug info"));
303 return;
304 }
305
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306 insert_into_vector<32>(&this->data_, 0xFFFFFFFF);
307 insert_into_vector<32>(&this->data_, 0);
308 insert_into_vector<64>(
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309 &this->data_,
310 (11 + get_length_as_unsigned_LEB_128(abbreviation_number)
311 + die_end - debug_info));
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312 insert_into_vector<16>(&this->data_, version);
313 insert_into_vector<64>(&this->data_, 0);
314 insert_into_vector<8>(&this->data_, address_size);
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315 write_unsigned_LEB_128(&this->data_, abbreviation_number);
316 this->data_.insert(this->data_.end(), debug_info, die_end);
317 }
318 else
319 {
320 const int dwarf32_header_size =
321 sizeof(uint16_t) + sizeof(uint32_t) + sizeof(uint8_t);
322 if (debug_info + dwarf32_header_size >= debug_info_end)
323 {
324 this->failed(_("Debug info extends beyond .debug_info section; "
325 "failed to reduce debug info"));
326 return;
327 }
328 uint32_t compile_unit_size = compile_unit_start;
329 next_compile_unit = debug_info + compile_unit_size;
330 uint16_t version = read_from_pointer<16>(&debug_info);
331 uint32_t abbrev_offset = read_from_pointer<32>(&debug_info);
332 uint8_t address_size = read_from_pointer<8>(&debug_info);
333 size_t LEB_size;
334 uint64_t abbreviation_number = read_unsigned_LEB_128(debug_info,
335 &LEB_size);
336 debug_info += LEB_size;
337 unsigned char* die_abbrev = this->associated_abbrev_->get_new_abbrev(
338 &abbreviation_number, abbrev_offset);
339 unsigned char* die_end;
340 if (!this->get_die_end(debug_info, die_abbrev, &die_end,
341 debug_info_end, address_size, false))
342 {
343 this->failed(_("Invalid DIE in debug info; "
344 "failed to reduce debug info"));
345 return;
346 }
347
e0ebcf42 348 insert_into_vector<32>(
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349 &this->data_,
350 (7 + get_length_as_unsigned_LEB_128(abbreviation_number)
351 + die_end - debug_info));
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352 insert_into_vector<16>(&this->data_, version);
353 insert_into_vector<32>(&this->data_, 0);
354 insert_into_vector<8>(&this->data_, address_size);
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355 write_unsigned_LEB_128(&this->data_, abbreviation_number);
356 this->data_.insert(this->data_.end(), debug_info, die_end);
357 }
358 debug_info = next_compile_unit;
359 }
360 this->set_data_size(data_.size());
361}
362
363void Output_reduced_debug_info_section::do_write(Output_file* of)
364{
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365 off_t offset = this->offset();
366 off_t data_size = this->data_size();
367 unsigned char* view = of->get_output_view(offset, data_size);
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368 if (this->failed_)
369 memcpy(view, this->postprocessing_buffer(),
370 this->postprocessing_buffer_size());
371 else
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372 memcpy(view, &this->data_.front(), data_size);
373 of->write_output_view(offset, data_size, view);
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374}
375
376} // End namespace gold.
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