tools/gn/loader.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "tools/gn/loader.h"
   6
   7 #include "base/bind.h"
   8 #include "base/message_loop/message_loop.h"
   9 #include "base/stl_util.h"
  10 #include "tools/gn/build_settings.h"
  11 #include "tools/gn/err.h"
  12 #include "tools/gn/filesystem_utils.h"
  13 #include "tools/gn/input_file_manager.h"
  14 #include "tools/gn/parse_tree.h"
  15 #include "tools/gn/scheduler.h"
  16 #include "tools/gn/scope_per_file_provider.h"
  17 #include "tools/gn/settings.h"
  18 #include "tools/gn/source_dir.h"
  19 #include "tools/gn/source_file.h"
  20 #include "tools/gn/trace.h"
  21
  22 namespace {
  23
  24 std::string GetOutputSubdirName(const Label& toolchain_label, bool is_default) {
  25   // The default toolchain has no subdir.
  26   if (is_default)
  27     return std::string();
  28
  29   // For now just assume the toolchain name is always a valid dir name. We may
  30   // want to clean up the in the future.
  31   return toolchain_label.name();
  32 }
  33
  34 }  // namespace
  35
  36 // Identifies one time a file is loaded in a given toolchain so we don't load
  37 // it more than once.
  38 struct LoaderImpl::LoadID {
  39   LoadID() {}
  40   LoadID(const SourceFile& f, const Label& tc_name)
  41       : file(f),
  42         toolchain_name(tc_name) {
  43   }
  44
  45   bool operator<(const LoadID& other) const {
  46     if (file.value() == other.file.value())
  47       return toolchain_name < other.toolchain_name;
  48     return file < other.file;
  49   }
  50
  51   SourceFile file;
  52   Label toolchain_name;
  53 };
  54
  55 // Our tracking information for a toolchain.
  56 struct LoaderImpl::ToolchainRecord {
  57   // The default toolchain label can be empty for the first time the default
  58   // toolchain is loaded, since we don't know it yet. This will be fixed up
  59   // later. It should be valid in all other cases.
  60   ToolchainRecord(const BuildSettings* build_settings,
  61                   const Label& toolchain_label,
  62                   const Label& default_toolchain_label)
  63       : settings(build_settings,
  64                  GetOutputSubdirName(toolchain_label,
  65                      toolchain_label == default_toolchain_label)),
  66         is_toolchain_loaded(false),
  67         is_config_loaded(false) {
  68     settings.set_default_toolchain_label(default_toolchain_label);
  69     settings.set_toolchain_label(toolchain_label);
  70   }
  71
  72   Settings settings;
  73
  74   bool is_toolchain_loaded;
  75   bool is_config_loaded;
  76
  77   std::vector<SourceFile> waiting_on_me;
  78 };
  79
  80 // -----------------------------------------------------------------------------
  81
  82 const void* Loader::kDefaultToolchainKey = &kDefaultToolchainKey;
  83
  84 Loader::Loader() {
  85 }
  86
  87 Loader::~Loader() {
  88 }
  89
  90 void Loader::Load(const Label& label) {
  91   Load(BuildFileForLabel(label), label.GetToolchainLabel());
  92 }
  93
  94 // static
  95 SourceFile Loader::BuildFileForLabel(const Label& label) {
  96   return SourceFile(label.dir().value() + "BUILD.gn");
  97 }
  98
  99 // -----------------------------------------------------------------------------
 100
 101 LoaderImpl::LoaderImpl(const BuildSettings* build_settings)
 102     : main_loop_(base::MessageLoop::current()),
 103       pending_loads_(0),
 104       build_settings_(build_settings) {
 105 }
 106
 107 LoaderImpl::~LoaderImpl() {
 108   STLDeleteContainerPairSecondPointers(toolchain_records_.begin(),
 109                                        toolchain_records_.end());
 110 }
 111
 112 void LoaderImpl::Load(const SourceFile& file,
 113     const Label& in_toolchain_name) {
 114   const Label& toolchain_name = in_toolchain_name.is_null()
 115       ? default_toolchain_label_ : in_toolchain_name;
 116   LoadID load_id(file, toolchain_name);
 117   if (!invocations_.insert(load_id).second)
 118     return;  // Already in set, so this file was already loaded or schedulerd.
 119
 120   if (toolchain_records_.empty()) {
 121     // Nothing loaded, need to load the default build config. The intial load
 122     // should not specify a toolchain.
 123     DCHECK(toolchain_name.is_null());
 124
 125     ToolchainRecord* record =
 126         new ToolchainRecord(build_settings_, Label(), Label());
 127     toolchain_records_[Label()] = record;
 128
 129     // The default build config is no dependent on the toolchain definition,
 130     // since we need to load the build config before we know what the default
 131     // toolchain name is.
 132     record->is_toolchain_loaded = true;
 133
 134     record->waiting_on_me.push_back(file);
 135     ScheduleLoadBuildConfig(&record->settings, Scope::KeyValueMap());
 136     return;
 137   }
 138
 139   ToolchainRecord* record;
 140   if (toolchain_name.is_null())
 141     record = toolchain_records_[default_toolchain_label_];
 142   else
 143     record = toolchain_records_[toolchain_name];
 144
 145   if (!record) {
 146     DCHECK(!default_toolchain_label_.is_null());
 147
 148     // No reference to this toolchain found yet, make one.
 149     record = new ToolchainRecord(build_settings_, toolchain_name,
 150                                  default_toolchain_label_);
 151     toolchain_records_[toolchain_name] = record;
 152
 153     // Schedule a load of the toolchain using the default one.
 154     Load(BuildFileForLabel(toolchain_name), default_toolchain_label_);
 155   }
 156
 157   if (record->is_config_loaded)
 158     ScheduleLoadFile(&record->settings, file);
 159   else
 160     record->waiting_on_me.push_back(file);
 161 }
 162
 163 void LoaderImpl::ToolchainLoaded(const Toolchain* toolchain) {
 164   ToolchainRecord* record = toolchain_records_[toolchain->label()];
 165   if (!record) {
 166     DCHECK(!default_toolchain_label_.is_null());
 167     record = new ToolchainRecord(build_settings_, toolchain->label(),
 168                                  default_toolchain_label_);
 169     toolchain_records_[toolchain->label()] = record;
 170   }
 171   record->is_toolchain_loaded = true;
 172
 173   // The default build config is loaded first, then its toolchain. Secondary
 174   // ones are loaded in the opposite order so we can pass toolchain parameters
 175   // to the build config. So we may or may not have a config at this point.
 176   if (!record->is_config_loaded) {
 177     ScheduleLoadBuildConfig(&record->settings, toolchain->args());
 178   } else {
 179     // There should be nobody waiting on this if the build config is already
 180     // loaded.
 181     DCHECK(record->waiting_on_me.empty());
 182   }
 183 }
 184
 185 Label LoaderImpl::GetDefaultToolchain() const {
 186   return default_toolchain_label_;
 187 }
 188
 189 const Settings* LoaderImpl::GetToolchainSettings(const Label& label) const {
 190   ToolchainRecordMap::const_iterator found_toolchain;
 191   if (label.is_null()) {
 192     if (default_toolchain_label_.is_null())
 193       return NULL;
 194     found_toolchain = toolchain_records_.find(default_toolchain_label_);
 195   } else {
 196     found_toolchain = toolchain_records_.find(label);
 197   }
 198
 199   if (found_toolchain == toolchain_records_.end())
 200     return NULL;
 201   return &found_toolchain->second->settings;
 202 }
 203
 204 void LoaderImpl::ScheduleLoadFile(const Settings* settings,
 205                                   const SourceFile& file) {
 206   Err err;
 207   pending_loads_++;
 208   if (!AsyncLoadFile(LocationRange(), settings->build_settings(), file,
 209                      base::Bind(&LoaderImpl::BackgroundLoadFile, this,
 210                                 settings, file),
 211                      &err)) {
 212     g_scheduler->FailWithError(err);
 213     DecrementPendingLoads();
 214   }
 215 }
 216
 217 void LoaderImpl::ScheduleLoadBuildConfig(
 218     Settings* settings,
 219     const Scope::KeyValueMap& toolchain_overrides) {
 220   Err err;
 221   pending_loads_++;
 222   if (!AsyncLoadFile(LocationRange(), settings->build_settings(),
 223                      settings->build_settings()->build_config_file(),
 224                      base::Bind(&LoaderImpl::BackgroundLoadBuildConfig,
 225                                 this, settings, toolchain_overrides),
 226                      &err)) {
 227     g_scheduler->FailWithError(err);
 228     DecrementPendingLoads();
 229   }
 230 }
 231
 232 void LoaderImpl::BackgroundLoadFile(const Settings* settings,
 233                                     const SourceFile& file_name,
 234                                     const ParseNode* root) {
 235   if (!root) {
 236     main_loop_->PostTask(FROM_HERE,
 237         base::Bind(&LoaderImpl::DecrementPendingLoads, this));
 238     return;
 239   }
 240
 241   if (g_scheduler->verbose_logging()) {
 242     g_scheduler->Log("Running", file_name.value() + " with toolchain " +
 243                      settings->toolchain_label().GetUserVisibleName(false));
 244   }
 245
 246   Scope our_scope(settings->base_config());
 247   ScopePerFileProvider per_file_provider(&our_scope);
 248   our_scope.set_source_dir(file_name.GetDir());
 249
 250   ScopedTrace trace(TraceItem::TRACE_FILE_EXECUTE, file_name.value());
 251   trace.SetToolchain(settings->toolchain_label());
 252
 253   Err err;
 254   root->Execute(&our_scope, &err);
 255   if (err.has_error())
 256     g_scheduler->FailWithError(err);
 257
 258   trace.Done();
 259
 260   main_loop_->PostTask(FROM_HERE, base::Bind(&LoaderImpl::DidLoadFile, this));
 261 }
 262
 263 void LoaderImpl::BackgroundLoadBuildConfig(
 264     Settings* settings,
 265     const Scope::KeyValueMap& toolchain_overrides,
 266     const ParseNode* root) {
 267   if (!root) {
 268     main_loop_->PostTask(FROM_HERE,
 269         base::Bind(&LoaderImpl::DecrementPendingLoads, this));
 270     return;
 271   }
 272
 273   Scope* base_config = settings->base_config();
 274   base_config->set_source_dir(SourceDir("//"));
 275
 276   settings->build_settings()->build_args().SetupRootScope(
 277       base_config, toolchain_overrides);
 278
 279   base_config->SetProcessingBuildConfig();
 280
 281   // See kDefaultToolchainKey in the header.
 282   Label default_toolchain_label;
 283   if (settings->is_default())
 284     base_config->SetProperty(kDefaultToolchainKey, &default_toolchain_label);
 285
 286   ScopedTrace trace(TraceItem::TRACE_FILE_EXECUTE,
 287       settings->build_settings()->build_config_file().value());
 288   trace.SetToolchain(settings->toolchain_label());
 289
 290   const BlockNode* root_block = root->AsBlock();
 291   Err err;
 292   root_block->ExecuteBlockInScope(base_config, &err);
 293
 294   trace.Done();
 295
 296   if (err.has_error())
 297     g_scheduler->FailWithError(err);
 298
 299   base_config->ClearProcessingBuildConfig();
 300   if (settings->is_default()) {
 301     // The default toolchain must have been set in the default build config
 302     // file.
 303     if (default_toolchain_label.is_null()) {
 304       g_scheduler->FailWithError(Err(Location(),
 305           "The default build config file did not call set_default_toolchain()",
 306           "If you don't call this, I can't figure out what toolchain to use\n"
 307           "for all of this code."));
 308     } else {
 309       DCHECK(settings->toolchain_label().is_null());
 310       settings->set_toolchain_label(default_toolchain_label);
 311     }
 312   }
 313
 314   main_loop_->PostTask(FROM_HERE,
 315       base::Bind(&LoaderImpl::DidLoadBuildConfig, this,
 316                  settings->toolchain_label()));
 317 }
 318
 319 void LoaderImpl::DidLoadFile() {
 320   DecrementPendingLoads();
 321 }
 322
 323 void LoaderImpl::DidLoadBuildConfig(const Label& label) {
 324   // Do not return early, we must call DecrementPendingLoads() at the bottom.
 325
 326   ToolchainRecordMap::iterator found_toolchain = toolchain_records_.find(label);
 327   ToolchainRecord* record = NULL;
 328   if (found_toolchain == toolchain_records_.end()) {
 329     // When loading the default build config, we'll insert it into the record
 330     // map with an empty label since we don't yet know what to call it.
 331     //
 332     // In this case, we should have exactly one entry in the map with an empty
 333     // label. We now need to fix up the naming so it refers to the "real" one.
 334     CHECK(toolchain_records_.size() == 1);
 335     ToolchainRecordMap::iterator empty_label = toolchain_records_.find(Label());
 336     CHECK(empty_label != toolchain_records_.end());
 337
 338     // Fix up the toolchain record.
 339     record = empty_label->second;
 340     toolchain_records_[label] = record;
 341     toolchain_records_.erase(empty_label);
 342
 343     // Save the default toolchain label.
 344     default_toolchain_label_ = label;
 345     DCHECK(record->settings.default_toolchain_label().is_null());
 346     record->settings.set_default_toolchain_label(label);
 347
 348     // The settings object should have the toolchain label already set.
 349     DCHECK(!record->settings.toolchain_label().is_null());
 350
 351     // Update any stored invocations that refer to the empty toolchain label.
 352     // This will normally only be one, for the root build file, so brute-force
 353     // is OK.
 354     LoadIDSet old_loads;
 355     invocations_.swap(old_loads);
 356     for (LoadIDSet::iterator i = old_loads.begin();
 357          i != old_loads.end(); ++i) {
 358       if (i->toolchain_name.is_null()) {
 359         // Fix up toolchain label
 360         invocations_.insert(LoadID(i->file, label));
 361       } else {
 362         // Can keep the old one.
 363         invocations_.insert(*i);
 364       }
 365     }
 366   } else {
 367     record = found_toolchain->second;
 368   }
 369
 370   DCHECK(!record->is_config_loaded);
 371   DCHECK(record->is_toolchain_loaded);
 372   record->is_config_loaded = true;
 373
 374   // Schedule all waiting file loads.
 375   for (size_t i = 0; i < record->waiting_on_me.size(); i++)
 376     ScheduleLoadFile(&record->settings, record->waiting_on_me[i]);
 377   record->waiting_on_me.clear();
 378
 379   DecrementPendingLoads();
 380 }
 381
 382 void LoaderImpl::DecrementPendingLoads() {
 383   DCHECK(pending_loads_ > 0);
 384   pending_loads_--;
 385   if (pending_loads_ == 0 && !complete_callback_.is_null())
 386     complete_callback_.Run();
 387 }
 388
 389 bool LoaderImpl::AsyncLoadFile(
 390     const LocationRange& origin,
 391     const BuildSettings* build_settings,
 392     const SourceFile& file_name,
 393     const base::Callback<void(const ParseNode*)>& callback,
 394     Err* err) {
 395   if (async_load_file_.is_null()) {
 396     return g_scheduler->input_file_manager()->AsyncLoadFile(
 397         origin, build_settings, file_name, callback, err);
 398   }
 399   return async_load_file_.Run(
 400       origin, build_settings, file_name, callback, err);
 401 }