1ed0d50c3Schristos // compressed_output.cc -- manage compressed debug sections for gold
2ed0d50c3Schristos
3*b88e3e88Schristos // Copyright (C) 2007-2020 Free Software Foundation, Inc.
4ed0d50c3Schristos // Written by Ian Lance Taylor <iant@google.com>.
5ed0d50c3Schristos
6ed0d50c3Schristos // This file is part of gold.
7ed0d50c3Schristos
8ed0d50c3Schristos // This program is free software; you can redistribute it and/or modify
9ed0d50c3Schristos // it under the terms of the GNU General Public License as published by
10ed0d50c3Schristos // the Free Software Foundation; either version 3 of the License, or
11ed0d50c3Schristos // (at your option) any later version.
12ed0d50c3Schristos
13ed0d50c3Schristos // This program is distributed in the hope that it will be useful,
14ed0d50c3Schristos // but WITHOUT ANY WARRANTY; without even the implied warranty of
15ed0d50c3Schristos // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16ed0d50c3Schristos // GNU General Public License for more details.
17ed0d50c3Schristos
18ed0d50c3Schristos // You should have received a copy of the GNU General Public License
19ed0d50c3Schristos // along with this program; if not, write to the Free Software
20ed0d50c3Schristos // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21ed0d50c3Schristos // MA 02110-1301, USA.
22ed0d50c3Schristos
23ed0d50c3Schristos #include "gold.h"
24ed0d50c3Schristos #include <zlib.h>
25ed0d50c3Schristos #include "parameters.h"
26ed0d50c3Schristos #include "options.h"
27ed0d50c3Schristos #include "compressed_output.h"
28ed0d50c3Schristos
29ed0d50c3Schristos namespace gold
30ed0d50c3Schristos {
31ed0d50c3Schristos
32ed0d50c3Schristos // Compress UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns true
33ed0d50c3Schristos // if it successfully compressed, false if it failed for any reason
34ed0d50c3Schristos // (including not having zlib support in the library). If it returns
35ed0d50c3Schristos // true, it allocates memory for the compressed data using new, and
36ed0d50c3Schristos // sets *COMPRESSED_DATA and *COMPRESSED_SIZE to appropriate values.
37ed0d50c3Schristos // It also writes a header before COMPRESSED_DATA: 4 bytes saying
38ed0d50c3Schristos // "ZLIB", and 8 bytes indicating the uncompressed size, in big-endian
39ed0d50c3Schristos // order.
40ed0d50c3Schristos
41ed0d50c3Schristos static bool
zlib_compress(int header_size,const unsigned char * uncompressed_data,unsigned long uncompressed_size,unsigned char ** compressed_data,unsigned long * compressed_size)42ed0d50c3Schristos zlib_compress(int header_size,
43ed0d50c3Schristos const unsigned char* uncompressed_data,
44ed0d50c3Schristos unsigned long uncompressed_size,
45ed0d50c3Schristos unsigned char** compressed_data,
46ed0d50c3Schristos unsigned long* compressed_size)
47ed0d50c3Schristos {
48ed0d50c3Schristos *compressed_size = uncompressed_size + uncompressed_size / 1000 + 128;
49ed0d50c3Schristos *compressed_data = new unsigned char[*compressed_size + header_size];
50ed0d50c3Schristos
51ed0d50c3Schristos int compress_level;
52ed0d50c3Schristos if (parameters->options().optimize() >= 1)
53ed0d50c3Schristos compress_level = 9;
54ed0d50c3Schristos else
55ed0d50c3Schristos compress_level = 1;
56ed0d50c3Schristos
57ed0d50c3Schristos int rc = compress2(reinterpret_cast<Bytef*>(*compressed_data) + header_size,
58ed0d50c3Schristos compressed_size,
59ed0d50c3Schristos reinterpret_cast<const Bytef*>(uncompressed_data),
60ed0d50c3Schristos uncompressed_size,
61ed0d50c3Schristos compress_level);
62ed0d50c3Schristos if (rc == Z_OK)
63ed0d50c3Schristos {
64ed0d50c3Schristos *compressed_size += header_size;
65ed0d50c3Schristos return true;
66ed0d50c3Schristos }
67ed0d50c3Schristos else
68ed0d50c3Schristos {
69ed0d50c3Schristos delete[] *compressed_data;
70ed0d50c3Schristos *compressed_data = NULL;
71ed0d50c3Schristos return false;
72ed0d50c3Schristos }
73ed0d50c3Schristos }
74ed0d50c3Schristos
75ed0d50c3Schristos // Decompress COMPRESSED_DATA of size COMPRESSED_SIZE, into a buffer
76ed0d50c3Schristos // UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns TRUE if it
77ed0d50c3Schristos // decompressed successfully, false if it failed. The buffer, of
78ed0d50c3Schristos // appropriate size, is provided by the caller, and is typically part
79ed0d50c3Schristos // of the memory-mapped output file.
80ed0d50c3Schristos
81ed0d50c3Schristos static bool
zlib_decompress(const unsigned char * compressed_data,unsigned long compressed_size,unsigned char * uncompressed_data,unsigned long uncompressed_size)82ed0d50c3Schristos zlib_decompress(const unsigned char* compressed_data,
83ed0d50c3Schristos unsigned long compressed_size,
84ed0d50c3Schristos unsigned char* uncompressed_data,
85ed0d50c3Schristos unsigned long uncompressed_size)
86ed0d50c3Schristos {
87ed0d50c3Schristos z_stream strm;
88ed0d50c3Schristos int rc;
89ed0d50c3Schristos
90ed0d50c3Schristos /* It is possible the section consists of several compressed
91ed0d50c3Schristos buffers concatenated together, so we uncompress in a loop. */
92ed0d50c3Schristos strm.zalloc = NULL;
93ed0d50c3Schristos strm.zfree = NULL;
94ed0d50c3Schristos strm.opaque = NULL;
95ed0d50c3Schristos strm.avail_in = compressed_size;
96ed0d50c3Schristos strm.next_in = const_cast<Bytef*>(compressed_data);
97ed0d50c3Schristos strm.avail_out = uncompressed_size;
98ed0d50c3Schristos
99ed0d50c3Schristos rc = inflateInit(&strm);
100ed0d50c3Schristos while (strm.avail_in > 0)
101ed0d50c3Schristos {
102ed0d50c3Schristos if (rc != Z_OK)
103ed0d50c3Schristos return false;
104ed0d50c3Schristos strm.next_out = ((Bytef*) uncompressed_data
105ed0d50c3Schristos + (uncompressed_size - strm.avail_out));
106ed0d50c3Schristos rc = inflate(&strm, Z_FINISH);
107ed0d50c3Schristos if (rc != Z_STREAM_END)
108ed0d50c3Schristos return false;
109ed0d50c3Schristos rc = inflateReset(&strm);
110ed0d50c3Schristos }
111ed0d50c3Schristos rc = inflateEnd(&strm);
112ed0d50c3Schristos if (rc != Z_OK || strm.avail_out != 0)
113ed0d50c3Schristos return false;
114ed0d50c3Schristos
115ed0d50c3Schristos return true;
116ed0d50c3Schristos }
117ed0d50c3Schristos
118ed0d50c3Schristos // Read the compression header of a compressed debug section and return
119ed0d50c3Schristos // the uncompressed size.
120ed0d50c3Schristos
121ed0d50c3Schristos uint64_t
get_uncompressed_size(const unsigned char * compressed_data,section_size_type compressed_size)122ed0d50c3Schristos get_uncompressed_size(const unsigned char* compressed_data,
123ed0d50c3Schristos section_size_type compressed_size)
124ed0d50c3Schristos {
125ed0d50c3Schristos const unsigned int zlib_header_size = 12;
126ed0d50c3Schristos
127ed0d50c3Schristos /* Verify the compression header. Currently, we support only zlib
128ed0d50c3Schristos compression, so it should be "ZLIB" followed by the uncompressed
129ed0d50c3Schristos section size, 8 bytes in big-endian order. */
130ed0d50c3Schristos if (compressed_size >= zlib_header_size
131ed0d50c3Schristos && strncmp(reinterpret_cast<const char*>(compressed_data),
132ed0d50c3Schristos "ZLIB", 4) == 0)
133ed0d50c3Schristos return elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4);
134ed0d50c3Schristos return -1ULL;
135ed0d50c3Schristos }
136ed0d50c3Schristos
137ed0d50c3Schristos // Decompress a compressed debug section directly into the output file.
138ed0d50c3Schristos
139ed0d50c3Schristos bool
decompress_input_section(const unsigned char * compressed_data,unsigned long compressed_size,unsigned char * uncompressed_data,unsigned long uncompressed_size,int size,bool big_endian,elfcpp::Elf_Xword sh_flags)140ed0d50c3Schristos decompress_input_section(const unsigned char* compressed_data,
141ed0d50c3Schristos unsigned long compressed_size,
142ed0d50c3Schristos unsigned char* uncompressed_data,
143ed0d50c3Schristos unsigned long uncompressed_size,
144ed0d50c3Schristos int size,
145ed0d50c3Schristos bool big_endian,
146ed0d50c3Schristos elfcpp::Elf_Xword sh_flags)
147ed0d50c3Schristos {
148ed0d50c3Schristos if ((sh_flags & elfcpp::SHF_COMPRESSED) != 0)
149ed0d50c3Schristos {
150ed0d50c3Schristos unsigned int compression_header_size;
151ed0d50c3Schristos if (size == 32)
152ed0d50c3Schristos {
153ed0d50c3Schristos compression_header_size = elfcpp::Elf_sizes<32>::chdr_size;
154ed0d50c3Schristos if (big_endian)
155ed0d50c3Schristos {
156ed0d50c3Schristos elfcpp::Chdr<32, true> chdr(compressed_data);
157ed0d50c3Schristos if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB)
158ed0d50c3Schristos return false;
159ed0d50c3Schristos }
160ed0d50c3Schristos else
161ed0d50c3Schristos {
162ed0d50c3Schristos elfcpp::Chdr<32, false> chdr(compressed_data);
163ed0d50c3Schristos if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB)
164ed0d50c3Schristos return false;
165ed0d50c3Schristos }
166ed0d50c3Schristos }
167ed0d50c3Schristos else if (size == 64)
168ed0d50c3Schristos {
169ed0d50c3Schristos compression_header_size = elfcpp::Elf_sizes<64>::chdr_size;
170ed0d50c3Schristos if (big_endian)
171ed0d50c3Schristos {
172ed0d50c3Schristos elfcpp::Chdr<64, true> chdr(compressed_data);
173ed0d50c3Schristos if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB)
174ed0d50c3Schristos return false;
175ed0d50c3Schristos }
176ed0d50c3Schristos else
177ed0d50c3Schristos {
178ed0d50c3Schristos elfcpp::Chdr<64, false> chdr(compressed_data);
179ed0d50c3Schristos if (chdr.get_ch_type() != elfcpp::ELFCOMPRESS_ZLIB)
180ed0d50c3Schristos return false;
181ed0d50c3Schristos }
182ed0d50c3Schristos }
183ed0d50c3Schristos else
184ed0d50c3Schristos gold_unreachable();
185ed0d50c3Schristos
186ed0d50c3Schristos return zlib_decompress(compressed_data + compression_header_size,
187ed0d50c3Schristos compressed_size - compression_header_size,
188ed0d50c3Schristos uncompressed_data,
189ed0d50c3Schristos uncompressed_size);
190ed0d50c3Schristos }
191ed0d50c3Schristos
192ed0d50c3Schristos const unsigned int zlib_header_size = 12;
193ed0d50c3Schristos
194ed0d50c3Schristos /* Verify the compression header. Currently, we support only zlib
195ed0d50c3Schristos compression, so it should be "ZLIB" followed by the uncompressed
196ed0d50c3Schristos section size, 8 bytes in big-endian order. */
197ed0d50c3Schristos if (compressed_size >= zlib_header_size
198ed0d50c3Schristos && strncmp(reinterpret_cast<const char*>(compressed_data),
199ed0d50c3Schristos "ZLIB", 4) == 0)
200ed0d50c3Schristos {
201ed0d50c3Schristos unsigned long uncompressed_size_check =
202ed0d50c3Schristos elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4);
203ed0d50c3Schristos gold_assert(uncompressed_size_check == uncompressed_size);
204ed0d50c3Schristos return zlib_decompress(compressed_data + zlib_header_size,
205ed0d50c3Schristos compressed_size - zlib_header_size,
206ed0d50c3Schristos uncompressed_data,
207ed0d50c3Schristos uncompressed_size);
208ed0d50c3Schristos }
209ed0d50c3Schristos return false;
210ed0d50c3Schristos }
211ed0d50c3Schristos
212ed0d50c3Schristos // Class Output_compressed_section.
213ed0d50c3Schristos
214ed0d50c3Schristos // Set the final data size of a compressed section. This is where
215ed0d50c3Schristos // we actually compress the section data.
216ed0d50c3Schristos
217ed0d50c3Schristos void
set_final_data_size()218ed0d50c3Schristos Output_compressed_section::set_final_data_size()
219ed0d50c3Schristos {
220ed0d50c3Schristos off_t uncompressed_size = this->postprocessing_buffer_size();
221ed0d50c3Schristos
222ed0d50c3Schristos // (Try to) compress the data.
223ed0d50c3Schristos unsigned long compressed_size;
224ed0d50c3Schristos unsigned char* uncompressed_data = this->postprocessing_buffer();
225ed0d50c3Schristos
226ed0d50c3Schristos // At this point the contents of all regular input sections will
227ed0d50c3Schristos // have been copied into the postprocessing buffer, and relocations
228ed0d50c3Schristos // will have been applied. Now we need to copy in the contents of
229ed0d50c3Schristos // anything other than a regular input section.
230ed0d50c3Schristos this->write_to_postprocessing_buffer();
231ed0d50c3Schristos
232ed0d50c3Schristos bool success = false;
233ed0d50c3Schristos enum { none, gnu_zlib, gabi_zlib } compress;
234ed0d50c3Schristos int compression_header_size = 12;
235ed0d50c3Schristos const int size = parameters->target().get_size();
236ed0d50c3Schristos if (strcmp(this->options_->compress_debug_sections(), "zlib-gnu") == 0)
237ed0d50c3Schristos compress = gnu_zlib;
238ed0d50c3Schristos else if (strcmp(this->options_->compress_debug_sections(), "zlib-gabi") == 0
239ed0d50c3Schristos || strcmp(this->options_->compress_debug_sections(), "zlib") == 0)
240ed0d50c3Schristos {
241ed0d50c3Schristos compress = gabi_zlib;
242ed0d50c3Schristos if (size == 32)
243ed0d50c3Schristos compression_header_size = elfcpp::Elf_sizes<32>::chdr_size;
244ed0d50c3Schristos else if (size == 64)
245ed0d50c3Schristos compression_header_size = elfcpp::Elf_sizes<64>::chdr_size;
246ed0d50c3Schristos else
247ed0d50c3Schristos gold_unreachable();
248ed0d50c3Schristos }
249ed0d50c3Schristos else
250ed0d50c3Schristos compress = none;
251ed0d50c3Schristos if (compress != none)
252ed0d50c3Schristos success = zlib_compress(compression_header_size, uncompressed_data,
253ed0d50c3Schristos uncompressed_size, &this->data_,
254ed0d50c3Schristos &compressed_size);
255ed0d50c3Schristos if (success)
256ed0d50c3Schristos {
257ed0d50c3Schristos elfcpp::Elf_Xword flags = this->flags();
258ed0d50c3Schristos if (compress == gabi_zlib)
259ed0d50c3Schristos {
260ed0d50c3Schristos // Set the SHF_COMPRESSED bit.
261ed0d50c3Schristos flags |= elfcpp::SHF_COMPRESSED;
262ed0d50c3Schristos const bool is_big_endian = parameters->target().is_big_endian();
263ed0d50c3Schristos uint64_t addralign = this->addralign();
264ed0d50c3Schristos if (size == 32)
265ed0d50c3Schristos {
266ed0d50c3Schristos if (is_big_endian)
267ed0d50c3Schristos {
268ed0d50c3Schristos elfcpp::Chdr_write<32, true> chdr(this->data_);
269ed0d50c3Schristos chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB);
270ed0d50c3Schristos chdr.put_ch_size(uncompressed_size);
271ed0d50c3Schristos chdr.put_ch_addralign(addralign);
272ed0d50c3Schristos }
273ed0d50c3Schristos else
274ed0d50c3Schristos {
275ed0d50c3Schristos elfcpp::Chdr_write<32, false> chdr(this->data_);
276ed0d50c3Schristos chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB);
277ed0d50c3Schristos chdr.put_ch_size(uncompressed_size);
278ed0d50c3Schristos chdr.put_ch_addralign(addralign);
279ed0d50c3Schristos }
280ed0d50c3Schristos }
281ed0d50c3Schristos else if (size == 64)
282ed0d50c3Schristos {
283ed0d50c3Schristos if (is_big_endian)
284ed0d50c3Schristos {
285ed0d50c3Schristos elfcpp::Chdr_write<64, true> chdr(this->data_);
286ed0d50c3Schristos chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB);
287ed0d50c3Schristos chdr.put_ch_size(uncompressed_size);
288ed0d50c3Schristos chdr.put_ch_addralign(addralign);
28906324dcfSchristos // Clear the reserved field.
29006324dcfSchristos chdr.put_ch_reserved(0);
291ed0d50c3Schristos }
292ed0d50c3Schristos else
293ed0d50c3Schristos {
294ed0d50c3Schristos elfcpp::Chdr_write<64, false> chdr(this->data_);
295ed0d50c3Schristos chdr.put_ch_type(elfcpp::ELFCOMPRESS_ZLIB);
296ed0d50c3Schristos chdr.put_ch_size(uncompressed_size);
297ed0d50c3Schristos chdr.put_ch_addralign(addralign);
29806324dcfSchristos // Clear the reserved field.
29906324dcfSchristos chdr.put_ch_reserved(0);
300ed0d50c3Schristos }
301ed0d50c3Schristos }
302ed0d50c3Schristos else
303ed0d50c3Schristos gold_unreachable();
304ed0d50c3Schristos }
305ed0d50c3Schristos else
306ed0d50c3Schristos {
307ed0d50c3Schristos // Write out the zlib header.
308ed0d50c3Schristos memcpy(this->data_, "ZLIB", 4);
309ed0d50c3Schristos elfcpp::Swap_unaligned<64, true>::writeval(this->data_ + 4,
310ed0d50c3Schristos uncompressed_size);
311ed0d50c3Schristos // This converts .debug_foo to .zdebug_foo
312ed0d50c3Schristos this->new_section_name_ = std::string(".z") + (this->name() + 1);
313ed0d50c3Schristos this->set_name(this->new_section_name_.c_str());
314ed0d50c3Schristos }
315ed0d50c3Schristos this->set_flags(flags);
316ed0d50c3Schristos this->set_data_size(compressed_size);
317ed0d50c3Schristos }
318ed0d50c3Schristos else
319ed0d50c3Schristos {
320ed0d50c3Schristos gold_warning(_("not compressing section data: zlib error"));
321ed0d50c3Schristos gold_assert(this->data_ == NULL);
322ed0d50c3Schristos this->set_data_size(uncompressed_size);
323ed0d50c3Schristos }
324ed0d50c3Schristos }
325ed0d50c3Schristos
326ed0d50c3Schristos // Write out a compressed section. If we couldn't compress, we just
327ed0d50c3Schristos // write it out as normal, uncompressed data.
328ed0d50c3Schristos
329ed0d50c3Schristos void
do_write(Output_file * of)330ed0d50c3Schristos Output_compressed_section::do_write(Output_file* of)
331ed0d50c3Schristos {
332ed0d50c3Schristos off_t offset = this->offset();
333ed0d50c3Schristos off_t data_size = this->data_size();
334ed0d50c3Schristos unsigned char* view = of->get_output_view(offset, data_size);
335ed0d50c3Schristos if (this->data_ == NULL)
336ed0d50c3Schristos memcpy(view, this->postprocessing_buffer(), data_size);
337ed0d50c3Schristos else
338ed0d50c3Schristos memcpy(view, this->data_, data_size);
339ed0d50c3Schristos of->write_output_view(offset, data_size, view);
340ed0d50c3Schristos }
341ed0d50c3Schristos
342ed0d50c3Schristos } // End namespace gold.
343