elf_loader.cc

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#include "flutter/testing/elf_loader.h"
 
#include <utility>
 
#include "flutter/fml/file.h"
#include "flutter/fml/paths.h"
#include "flutter/runtime/dart_vm.h"
#include "flutter/testing/testing.h"
 
namespace flutter::testing {
 
ELFAOTSymbols LoadELFSymbolFromFixturesIfNeccessary(std::string elf_filename) {
  if (!DartVM::IsRunningPrecompiledCode()) {
    return {};
  }
 
  const auto elf_path =
      fml::paths::JoinPaths({GetFixturesPath(), std::move(elf_filename)});
 
  if (!fml::IsFile(elf_path)) {
    FML_LOG(ERROR) << "App AOT file does not exist for this fixture. Attempts "
                      "to launch the Dart VM with these AOT symbols will fail.";
    return {};
  }
 
  ELFAOTSymbols symbols;
 
#if OS_FUCHSIA
  // TODO(gw280): https://github.com/flutter/flutter/issues/50285
  // Dart doesn't implement Dart_LoadELF on Fuchsia
  FML_LOG(ERROR) << "Dart doesn't implement Dart_LoadELF on Fuchsia";
  return {};
#else
  // Must not be freed.
  const char* error = nullptr;
 
  auto loaded_elf =
      Dart_LoadELF(elf_path.c_str(),           // file path
                   0,                          // file offset
                   &error,                     // error (out)
                   &symbols.vm_isolate_data,   // vm isolate data (out)
                   &symbols.vm_isolate_instrs  // vm isolate instr (out)
      );
  if (loaded_elf != nullptr) {
    symbols.vm_snapshot_data = symbols.vm_isolate_data;
    symbols.vm_snapshot_instrs = symbols.vm_isolate_instrs;
  }
 
  if (loaded_elf == nullptr) {
    FML_LOG(ERROR)
        << "Could not fetch AOT symbols from loaded ELF. Attempts "
           "to launch the Dart VM with these AOT symbols  will fail. Error: "
        << error;
    return {};
  }
 
  symbols.loaded_elf.reset(loaded_elf);
 
  return symbols;
#endif  // OS_FUCHSIA
}
 
ELFAOTSymbols LoadELFSplitSymbolFromFixturesIfNeccessary(
    std::string elf_split_filename) {
  if (!DartVM::IsRunningPrecompiledCode()) {
    return {};
  }
 
  const auto elf_path =
      fml::paths::JoinPaths({GetFixturesPath(), std::move(elf_split_filename)});
 
  if (!fml::IsFile(elf_path)) {
    // We do not log here, as there is no expectation for a split library to
    // exist.
    return {};
  }
 
  ELFAOTSymbols symbols;
 
#if OS_FUCHSIA
  // TODO(gw280): https://github.com/flutter/flutter/issues/50285
  // Dart doesn't implement Dart_LoadELF on Fuchsia
  FML_LOG(ERROR) << "Dart doesn't implement Dart_LoadELF on Fuchsia";
  return {};
#else
  // Must not be freed.
  const char* error = nullptr;
 
  auto loaded_elf =
      Dart_LoadELF(elf_path.c_str(),           // file path
                   0,                          // file offset
                   &error,                     // error (out)
                   &symbols.vm_isolate_data,   // vm isolate data (out)
                   &symbols.vm_isolate_instrs  // vm isolate instr (out)
      );
  if (loaded_elf != nullptr) {
    symbols.vm_snapshot_data = symbols.vm_isolate_data;
    symbols.vm_snapshot_instrs = symbols.vm_isolate_instrs;
  }
 
  if (loaded_elf == nullptr) {
    FML_LOG(ERROR)
        << "Could not fetch AOT symbols from loaded ELF. Attempts "
           "to launch the Dart VM with these AOT symbols  will fail. Error: "
        << error;
    return {};
  }
 
  symbols.loaded_elf.reset(loaded_elf);
 
  return symbols;
#endif
}
 
bool PrepareSettingsForAOTWithSymbols(Settings& settings,
                                      const ELFAOTSymbols& symbols) {
  if (!DartVM::IsRunningPrecompiledCode()) {
    return false;
  }
  settings.vm_snapshot_data = [&]() {
    return std::make_unique<fml::NonOwnedMapping>(symbols.vm_snapshot_data, 0u);
  };
  settings.isolate_snapshot_data = [&]() {
    return std::make_unique<fml::NonOwnedMapping>(symbols.vm_isolate_data, 0u);
  };
  settings.vm_snapshot_instr = [&]() {
    return std::make_unique<fml::NonOwnedMapping>(symbols.vm_snapshot_instrs,
                                                  0u);
  };
  settings.isolate_snapshot_instr = [&]() {
    return std::make_unique<fml::NonOwnedMapping>(symbols.vm_isolate_instrs,
                                                  0u);
  };
  return true;
}
 
}  // namespace flutter::testing