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https://sourceware.org/git/binutils-gdb.git
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292 lines
8.1 KiB
C
292 lines
8.1 KiB
C
/* Read MiniDebugInfo data from an objfile.
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Copyright (C) 2012-2020 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "gdb_bfd.h"
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#include "symfile.h"
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#include "objfiles.h"
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#include "gdbcore.h"
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#include <algorithm>
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#ifdef HAVE_LIBLZMA
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#include <lzma.h>
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/* Allocator function for LZMA. */
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static void *
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alloc_lzma (void *opaque, size_t nmemb, size_t size)
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{
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return xmalloc (nmemb * size);
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}
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/* Free function for LZMA. */
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static void
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free_lzma (void *opaque, void *ptr)
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{
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xfree (ptr);
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}
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/* The allocator object for LZMA. Note that 'gdb_lzma_allocator'
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cannot be const due to the lzma library function prototypes. */
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static lzma_allocator gdb_lzma_allocator = { alloc_lzma, free_lzma, NULL };
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/* Custom bfd_openr_iovec implementation to read compressed data from
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a section. This keeps only the last decompressed block in memory
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to allow larger data without using to much memory. */
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struct gdb_lzma_stream
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{
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/* Section of input BFD from which we are decoding data. */
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asection *section;
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/* lzma library decompression state. */
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lzma_index *index;
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/* Currently decoded block. */
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bfd_size_type data_start;
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bfd_size_type data_end;
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gdb_byte *data;
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};
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/* bfd_openr_iovec OPEN_P implementation for
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find_separate_debug_file_in_section. OPEN_CLOSURE is 'asection *'
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of the section to decompress.
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Return 'struct gdb_lzma_stream *' must be freed by caller by xfree,
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together with its INDEX lzma data. */
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static void *
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lzma_open (struct bfd *nbfd, void *open_closure)
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{
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asection *section = (asection *) open_closure;
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bfd_size_type size, offset;
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lzma_stream_flags options;
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gdb_byte footer[LZMA_STREAM_HEADER_SIZE];
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gdb_byte *indexdata;
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lzma_index *index;
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uint64_t memlimit = UINT64_MAX;
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struct gdb_lzma_stream *lstream;
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size_t pos;
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size = bfd_section_size (section);
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offset = section->filepos + size - LZMA_STREAM_HEADER_SIZE;
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if (size < LZMA_STREAM_HEADER_SIZE
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|| bfd_seek (section->owner, offset, SEEK_SET) != 0
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|| bfd_bread (footer, LZMA_STREAM_HEADER_SIZE, section->owner)
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!= LZMA_STREAM_HEADER_SIZE
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|| lzma_stream_footer_decode (&options, footer) != LZMA_OK
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|| offset < options.backward_size)
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{
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bfd_set_error (bfd_error_wrong_format);
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return NULL;
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}
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offset -= options.backward_size;
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indexdata = (gdb_byte *) xmalloc (options.backward_size);
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index = NULL;
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pos = 0;
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if (bfd_seek (section->owner, offset, SEEK_SET) != 0
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|| bfd_bread (indexdata, options.backward_size, section->owner)
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!= options.backward_size
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|| lzma_index_buffer_decode (&index, &memlimit, &gdb_lzma_allocator,
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indexdata, &pos, options.backward_size)
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!= LZMA_OK
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|| lzma_index_size (index) != options.backward_size)
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{
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xfree (indexdata);
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bfd_set_error (bfd_error_wrong_format);
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return NULL;
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}
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xfree (indexdata);
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lstream = XCNEW (struct gdb_lzma_stream);
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lstream->section = section;
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lstream->index = index;
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return lstream;
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}
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/* bfd_openr_iovec PREAD_P implementation for
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find_separate_debug_file_in_section. Passed STREAM
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is 'struct gdb_lzma_stream *'. */
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static file_ptr
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lzma_pread (struct bfd *nbfd, void *stream, void *buf, file_ptr nbytes,
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file_ptr offset)
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{
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struct gdb_lzma_stream *lstream = (struct gdb_lzma_stream *) stream;
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bfd_size_type chunk_size;
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lzma_index_iter iter;
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gdb_byte *compressed, *uncompressed;
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file_ptr block_offset;
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lzma_filter filters[LZMA_FILTERS_MAX + 1];
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lzma_block block;
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size_t compressed_pos, uncompressed_pos;
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file_ptr res;
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res = 0;
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while (nbytes > 0)
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{
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if (lstream->data == NULL
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|| lstream->data_start > offset || offset >= lstream->data_end)
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{
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asection *section = lstream->section;
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lzma_index_iter_init (&iter, lstream->index);
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if (lzma_index_iter_locate (&iter, offset))
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break;
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compressed = (gdb_byte *) xmalloc (iter.block.total_size);
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block_offset = section->filepos + iter.block.compressed_file_offset;
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if (bfd_seek (section->owner, block_offset, SEEK_SET) != 0
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|| bfd_bread (compressed, iter.block.total_size, section->owner)
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!= iter.block.total_size)
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{
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xfree (compressed);
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break;
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}
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uncompressed = (gdb_byte *) xmalloc (iter.block.uncompressed_size);
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memset (&block, 0, sizeof (block));
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block.filters = filters;
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block.header_size = lzma_block_header_size_decode (compressed[0]);
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if (lzma_block_header_decode (&block, &gdb_lzma_allocator, compressed)
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!= LZMA_OK)
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{
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xfree (compressed);
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xfree (uncompressed);
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break;
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}
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compressed_pos = block.header_size;
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uncompressed_pos = 0;
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if (lzma_block_buffer_decode (&block, &gdb_lzma_allocator,
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compressed, &compressed_pos,
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iter.block.total_size,
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uncompressed, &uncompressed_pos,
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iter.block.uncompressed_size)
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!= LZMA_OK)
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{
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xfree (compressed);
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xfree (uncompressed);
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break;
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}
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xfree (compressed);
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xfree (lstream->data);
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lstream->data = uncompressed;
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lstream->data_start = iter.block.uncompressed_file_offset;
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lstream->data_end = (iter.block.uncompressed_file_offset
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+ iter.block.uncompressed_size);
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}
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chunk_size = std::min (nbytes, (file_ptr) lstream->data_end - offset);
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memcpy (buf, lstream->data + offset - lstream->data_start, chunk_size);
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buf = (gdb_byte *) buf + chunk_size;
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offset += chunk_size;
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nbytes -= chunk_size;
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res += chunk_size;
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}
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return res;
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}
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/* bfd_openr_iovec CLOSE_P implementation for
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find_separate_debug_file_in_section. Passed STREAM
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is 'struct gdb_lzma_stream *'. */
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static int
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lzma_close (struct bfd *nbfd,
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void *stream)
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{
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struct gdb_lzma_stream *lstream = (struct gdb_lzma_stream *) stream;
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lzma_index_end (lstream->index, &gdb_lzma_allocator);
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xfree (lstream->data);
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xfree (lstream);
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/* Zero means success. */
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return 0;
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}
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/* bfd_openr_iovec STAT_P implementation for
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find_separate_debug_file_in_section. Passed STREAM
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is 'struct gdb_lzma_stream *'. */
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static int
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lzma_stat (struct bfd *abfd,
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void *stream,
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struct stat *sb)
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{
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struct gdb_lzma_stream *lstream = (struct gdb_lzma_stream *) stream;
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memset (sb, 0, sizeof (struct stat));
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sb->st_size = lzma_index_uncompressed_size (lstream->index);
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return 0;
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}
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#endif /* HAVE_LIBLZMA */
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/* This looks for a xz compressed separate debug info object file embedded
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in a section called .gnu_debugdata. See
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http://fedoraproject.org/wiki/Features/MiniDebugInfo
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or the "Separate Debug Sections" of the manual for details.
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If we find one we create a iovec based bfd that decompresses the
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object data on demand. If we don't find one, return NULL. */
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gdb_bfd_ref_ptr
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find_separate_debug_file_in_section (struct objfile *objfile)
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{
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asection *section;
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gdb_bfd_ref_ptr abfd;
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if (objfile->obfd == NULL)
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return NULL;
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section = bfd_get_section_by_name (objfile->obfd, ".gnu_debugdata");
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if (section == NULL)
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return NULL;
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#ifdef HAVE_LIBLZMA
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std::string filename = string_printf (_(".gnu_debugdata for %s"),
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objfile_name (objfile));
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abfd = gdb_bfd_openr_iovec (filename.c_str (), gnutarget, lzma_open,
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section, lzma_pread, lzma_close, lzma_stat);
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if (abfd == NULL)
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return NULL;
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if (!bfd_check_format (abfd.get (), bfd_object))
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{
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warning (_("Cannot parse .gnu_debugdata section; not a BFD object"));
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return NULL;
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}
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#else
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warning (_("Cannot parse .gnu_debugdata section; LZMA support was "
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"disabled at compile time"));
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#endif /* !HAVE_LIBLZMA */
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return abfd;
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}
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