| /* |
| * Copyright 2014-present Facebook, Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may |
| * not use this file except in compliance with the License. You may obtain |
| * a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| * License for the specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package com.facebook.buck.cxx; |
| |
| import static com.facebook.buck.cxx.DebugSectionProperty.COMPRESSED; |
| import static com.facebook.buck.cxx.DebugSectionProperty.STRINGS; |
| |
| import com.facebook.buck.cxx.elf.Elf; |
| import com.facebook.buck.cxx.elf.ElfSection; |
| import com.google.common.base.Optional; |
| import com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.ImmutableSet; |
| |
| import java.nio.ByteBuffer; |
| |
| public class DebugSectionFinder { |
| |
| // The ELF sections names which correspond to debug sections mapped to their properties. |
| private static final ImmutableMap<String, ImmutableSet<DebugSectionProperty>> ELF_DEBUG_SECTIONS = |
| ImmutableMap.<String, ImmutableSet<DebugSectionProperty>>builder() |
| // DWARF sections |
| .put(".debug_str", ImmutableSet.of(STRINGS)) |
| .put(".debug_line", ImmutableSet.of(STRINGS)) |
| .put(".zdebug_str", ImmutableSet.of(STRINGS, COMPRESSED)) |
| .put(".zdebug_line", ImmutableSet.of(STRINGS, COMPRESSED)) |
| // STABS sections |
| .put(".stabstr", ImmutableSet.of(STRINGS)) |
| .build(); |
| |
| // Locate, if any, the debug sections in the ELF file represented by the given buffer. |
| private ImmutableMap<String, DebugSection> findElf(ByteBuffer buffer) { |
| ImmutableMap.Builder<String, DebugSection> debugSectionsBuilder = ImmutableMap.builder(); |
| Elf elf = new Elf(buffer); |
| for (int i = 0; i < elf.getNumberOfSections(); i++) { |
| ElfSection section = elf.getSectionByIndex(i); |
| String name = elf.getSectionName(section.header); |
| ImmutableSet<DebugSectionProperty> properties = ELF_DEBUG_SECTIONS.get(name); |
| if (properties != null) { |
| buffer.position((int) section.header.sh_off); |
| ByteBuffer body = buffer.slice(); |
| body.limit((int) section.header.sh_size); |
| debugSectionsBuilder.put(name, new DebugSection(properties, body)); |
| } |
| } |
| return debugSectionsBuilder.build(); |
| } |
| |
| /** |
| * @return a map of all the debug sections found in executable format represented as |
| * {@code buffer}, or {@link Optional#absent()} if the format was not recognized. |
| */ |
| public Optional<ImmutableMap<String, DebugSection>> find(ByteBuffer buffer) { |
| if (Elf.isElf(buffer)) { |
| return Optional.of(findElf(buffer)); |
| } else { |
| return Optional.absent(); |
| } |
| } |
| |
| } |