compiler/dwarf/dwarf_test.h

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * 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.
 */

#ifndef ART_COMPILER_DWARF_DWARF_TEST_H_
#define ART_COMPILER_DWARF_DWARF_TEST_H_

#include <cstring>
#include <dirent.h>
#include <memory>
#include <set>
#include <stdio.h>
#include <string>
#include <sys/types.h>

#include "utils.h"
#include "base/unix_file/fd_file.h"
#include "common_runtime_test.h"
#include "elf_builder.h"
#include "gtest/gtest.h"
#include "os.h"

namespace art {
namespace dwarf {

#define DW_CHECK(substring) Check(substring, false, __FILE__, __LINE__)
#define DW_CHECK_NEXT(substring) Check(substring, true, __FILE__, __LINE__)

class DwarfTest : public CommonRuntimeTest {
 public:
  static constexpr bool kPrintObjdumpOutput = false;  // debugging.

  struct ExpectedLine {
    std::string substring;
    bool next;
    const char* at_file;
    int at_line;
  };

  // Check that the objdump output contains given output.
  // If next is true, it must be the next line.  Otherwise lines are skipped.
  void Check(const char* substr, bool next, const char* at_file, int at_line) {
    expected_lines_.push_back(ExpectedLine {substr, next, at_file, at_line});
  }

  static std::string GetObjdumpPath() {
    const char* android_build_top = getenv("ANDROID_BUILD_TOP");
    if (android_build_top != nullptr) {
      std::string host_prebuilts = std::string(android_build_top) +
                                   "/prebuilts/gcc/linux-x86/host/";
      // Read the content of the directory.
      std::set<std::string> entries;
      DIR* dir = opendir(host_prebuilts.c_str());
      if (dir != nullptr) {
        struct dirent* entry;
        while ((entry = readdir(dir)) != nullptr) {
          if (strstr(entry->d_name, "linux-glibc")) {
            entries.insert(host_prebuilts + entry->d_name);
          }
        }
        closedir(dir);
      }
      // Strings are sorted so the last one should be the most recent version.
      if (!entries.empty()) {
        std::string path = *entries.rbegin() + "/x86_64-linux/bin/objdump";
        struct stat st;
        if (stat(path.c_str(), &st) == 0) {
          return path;  // File exists.
        }
      }
    }
    ADD_FAILURE() << "Can not find prebuild objdump.";
    return "objdump";  // Use the system objdump as fallback.
  }

  // Pretty-print the generated DWARF data using objdump.
  template<typename Elf_Word, typename Elf_Sword, typename Elf_Addr, typename Elf_Dyn,
           typename Elf_Sym, typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr>
  std::vector<std::string> Objdump(bool is64bit, const char* args) {
    // Write simple elf file with just the DWARF sections.
    class NoCode : public CodeOutput {
      virtual void SetCodeOffset(size_t) { }
      virtual bool Write(OutputStream*) { return true; }
    } code;
    ScratchFile file;
    InstructionSet isa = is64bit ? kX86_64 : kX86;
    ElfBuilder<Elf_Word, Elf_Sword, Elf_Addr, Elf_Dyn,
               Elf_Sym, Elf_Ehdr, Elf_Phdr, Elf_Shdr> builder(
        &code, file.GetFile(), isa, 0, 0, 0, 0, 0, 0, false, false);
    typedef ElfRawSectionBuilder<Elf_Word, Elf_Sword, Elf_Shdr> Section;
    if (!debug_info_data_.empty()) {
      Section debug_info(".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
      debug_info.SetBuffer(debug_info_data_);
      builder.RegisterRawSection(debug_info);
    }
    if (!debug_abbrev_data_.empty()) {
      Section debug_abbrev(".debug_abbrev", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
      debug_abbrev.SetBuffer(debug_abbrev_data_);
      builder.RegisterRawSection(debug_abbrev);
    }
    if (!debug_str_data_.empty()) {
      Section debug_str(".debug_str", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
      debug_str.SetBuffer(debug_str_data_);
      builder.RegisterRawSection(debug_str);
    }
    if (!debug_line_data_.empty()) {
      Section debug_line(".debug_line", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
      debug_line.SetBuffer(debug_line_data_);
      builder.RegisterRawSection(debug_line);
    }
    if (!eh_frame_data_.empty()) {
      Section eh_frame(".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0);
      eh_frame.SetBuffer(eh_frame_data_);
      builder.RegisterRawSection(eh_frame);
    }
    builder.Init();
    builder.Write();

    // Read the elf file back using objdump.
    std::vector<std::string> lines;
    std::string cmd = GetObjdumpPath();
    cmd = cmd + " " + args + " " + file.GetFilename() + " 2>&1";
    FILE* output = popen(cmd.data(), "r");
    char buffer[1024];
    const char* line;
    while ((line = fgets(buffer, sizeof(buffer), output)) != nullptr) {
      if (kPrintObjdumpOutput) {
        printf("%s", line);
      }
      if (line[0] != '\0' && line[0] != '\n') {
        EXPECT_TRUE(strstr(line, "objdump: Error:") == nullptr) << line;
        EXPECT_TRUE(strstr(line, "objdump: Warning:") == nullptr) << line;
        std::string str(line);
        if (str.back() == '\n') {
          str.pop_back();
        }
        lines.push_back(str);
      }
    }
    pclose(output);
    return lines;
  }

  std::vector<std::string> Objdump(bool is64bit, const char* args) {
    if (is64bit) {
      return Objdump<Elf64_Word, Elf64_Sword, Elf64_Addr, Elf64_Dyn,
          Elf64_Sym, Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr>(is64bit, args);
    } else {
      return Objdump<Elf32_Word, Elf32_Sword, Elf32_Addr, Elf32_Dyn,
          Elf32_Sym, Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr>(is64bit, args);
    }
  }

  // Compare objdump output to the recorded checks.
  void CheckObjdumpOutput(bool is64bit, const char* args) {
    std::vector<std::string> actual_lines = Objdump(is64bit, args);
    auto actual_line = actual_lines.begin();
    for (const ExpectedLine& expected_line : expected_lines_) {
      const std::string& substring = expected_line.substring;
      if (actual_line == actual_lines.end()) {
        ADD_FAILURE_AT(expected_line.at_file, expected_line.at_line) <<
            "Expected '" << substring << "'.\n" <<
            "Seen end of output.";
      } else if (expected_line.next) {
        if (actual_line->find(substring) == std::string::npos) {
          ADD_FAILURE_AT(expected_line.at_file, expected_line.at_line) <<
            "Expected '" << substring << "'.\n" <<
            "Seen '" << actual_line->data() << "'.";
        } else {
          // printf("Found '%s' in '%s'.\n", substring.data(), actual_line->data());
        }
        actual_line++;
      } else {
        bool found = false;
        for (auto it = actual_line; it < actual_lines.end(); it++) {
          if (it->find(substring) != std::string::npos) {
            actual_line = it;
            found = true;
            break;
          }
        }
        if (!found) {
          ADD_FAILURE_AT(expected_line.at_file, expected_line.at_line) <<
            "Expected '" << substring << "'.\n" <<
            "Not found anywhere in the rest of the output.";
        } else {
          // printf("Found '%s' in '%s'.\n", substring.data(), actual_line->data());
          actual_line++;
        }
      }
    }
  }

  // Buffers which are going to assembled into ELF file and passed to objdump.
  std::vector<uint8_t> eh_frame_data_;
  std::vector<uint8_t> debug_info_data_;
  std::vector<uint8_t> debug_abbrev_data_;
  std::vector<uint8_t> debug_str_data_;
  std::vector<uint8_t> debug_line_data_;

  // The expected output of objdump.
  std::vector<ExpectedLine> expected_lines_;
};

}  // namespace dwarf
}  // namespace art

#endif  // ART_COMPILER_DWARF_DWARF_TEST_H_