tools/gn/ninja_build_writer.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/ninja_build_writer.h"
   6
   7 #include <fstream>
   8 #include <map>
   9
  10 #include "base/command_line.h"
  11 #include "base/files/file_util.h"
  12 #include "base/path_service.h"
  13 #include "base/process/process_handle.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/strings/utf_string_conversions.h"
  16 #include "build/build_config.h"
  17 #include "tools/gn/build_settings.h"
  18 #include "tools/gn/err.h"
  19 #include "tools/gn/escape.h"
  20 #include "tools/gn/filesystem_utils.h"
  21 #include "tools/gn/input_file_manager.h"
  22 #include "tools/gn/ninja_utils.h"
  23 #include "tools/gn/scheduler.h"
  24 #include "tools/gn/switches.h"
  25 #include "tools/gn/target.h"
  26 #include "tools/gn/trace.h"
  27
  28 #if defined(OS_WIN)
  29 #include <windows.h>
  30 #endif
  31
  32 namespace {
  33
  34 std::string GetSelfInvocationCommand(const BuildSettings* build_settings) {
  35   base::FilePath executable;
  36   PathService::Get(base::FILE_EXE, &executable);
  37
  38   base::CommandLine cmdline(executable.NormalizePathSeparatorsTo('/'));
  39   cmdline.AppendArg("gen");
  40   cmdline.AppendArg(build_settings->build_dir().value());
  41   cmdline.AppendSwitchPath(std::string("--") + switches::kRoot,
  42                            build_settings->root_path());
  43   // Successful automatic invocations shouldn't print output.
  44   cmdline.AppendSwitch(std::string("-") + switches::kQuiet);
  45
  46   EscapeOptions escape_shell;
  47   escape_shell.mode = ESCAPE_NINJA_COMMAND;
  48 #if defined(OS_WIN)
  49   // The command line code quoting varies by platform. We have one string,
  50   // possibly with spaces, that we want to quote. The Windows command line
  51   // quotes again, so we don't want quoting. The Posix one doesn't.
  52   escape_shell.inhibit_quoting = true;
  53 #endif
  54
  55   const base::CommandLine& our_cmdline =
  56       *base::CommandLine::ForCurrentProcess();
  57   const base::CommandLine::SwitchMap& switches = our_cmdline.GetSwitches();
  58   for (base::CommandLine::SwitchMap::const_iterator i = switches.begin();
  59        i != switches.end(); ++i) {
  60     // Only write arguments we haven't already written. Always skip "args"
  61     // since those will have been written to the file and will be used
  62     // implicitly in the future. Keeping --args would mean changes to the file
  63     // would be ignored.
  64     if (i->first != switches::kQuiet &&
  65         i->first != switches::kRoot &&
  66         i->first != switches::kArgs) {
  67       std::string escaped_value =
  68           EscapeString(FilePathToUTF8(i->second), escape_shell, nullptr);
  69       cmdline.AppendSwitchASCII(i->first, escaped_value);
  70     }
  71   }
  72
  73 #if defined(OS_WIN)
  74   return base::WideToUTF8(cmdline.GetCommandLineString());
  75 #else
  76   return cmdline.GetCommandLineString();
  77 #endif
  78 }
  79
  80 }  // namespace
  81
  82 NinjaBuildWriter::NinjaBuildWriter(
  83     const BuildSettings* build_settings,
  84     const std::vector<const Settings*>& all_settings,
  85     const Toolchain* default_toolchain,
  86     const std::vector<const Target*>& default_toolchain_targets,
  87     std::ostream& out,
  88     std::ostream& dep_out)
  89     : build_settings_(build_settings),
  90       all_settings_(all_settings),
  91       default_toolchain_(default_toolchain),
  92       default_toolchain_targets_(default_toolchain_targets),
  93       out_(out),
  94       dep_out_(dep_out),
  95       path_output_(build_settings->build_dir(),
  96                    build_settings->root_path_utf8(), ESCAPE_NINJA) {
  97 }
  98
  99 NinjaBuildWriter::~NinjaBuildWriter() {
 100 }
 101
 102 bool NinjaBuildWriter::Run(Err* err) {
 103   WriteNinjaRules();
 104   WriteLinkPool();
 105   WriteSubninjas();
 106   return WritePhonyAndAllRules(err);
 107 }
 108
 109 // static
 110 bool NinjaBuildWriter::RunAndWriteFile(
 111     const BuildSettings* build_settings,
 112     const std::vector<const Settings*>& all_settings,
 113     const Toolchain* default_toolchain,
 114     const std::vector<const Target*>& default_toolchain_targets,
 115     Err* err) {
 116   ScopedTrace trace(TraceItem::TRACE_FILE_WRITE, "build.ninja");
 117
 118   base::FilePath ninja_file(build_settings->GetFullPath(
 119       SourceFile(build_settings->build_dir().value() + "build.ninja")));
 120   base::CreateDirectory(ninja_file.DirName());
 121
 122   std::ofstream file;
 123   file.open(FilePathToUTF8(ninja_file).c_str(),
 124             std::ios_base::out | std::ios_base::binary);
 125   if (file.fail()) {
 126     *err = Err(Location(), "Couldn't open build.ninja for writing");
 127     return false;
 128   }
 129
 130   std::ofstream depfile;
 131   depfile.open((FilePathToUTF8(ninja_file) + ".d").c_str(),
 132                std::ios_base::out | std::ios_base::binary);
 133   if (depfile.fail()) {
 134     *err = Err(Location(), "Couldn't open depfile for writing");
 135     return false;
 136   }
 137
 138   NinjaBuildWriter gen(build_settings, all_settings, default_toolchain,
 139                        default_toolchain_targets, file, depfile);
 140   return gen.Run(err);
 141 }
 142
 143 void NinjaBuildWriter::WriteNinjaRules() {
 144   out_ << "rule gn\n";
 145   out_ << "  command = " << GetSelfInvocationCommand(build_settings_) << "\n";
 146   out_ << "  description = Regenerating ninja files\n\n";
 147
 148   // This rule will regenerate the ninja files when any input file has changed.
 149   out_ << "build build.ninja: gn\n"
 150        << "  generator = 1\n"
 151        << "  depfile = build.ninja.d\n";
 152
 153   // Input build files. These go in the ".d" file. If we write them as
 154   // dependencies in the .ninja file itself, ninja will expect the files to
 155   // exist and will error if they don't. When files are listed in a depfile,
 156   // missing files are ignored.
 157   dep_out_ << "build.ninja:";
 158   std::vector<base::FilePath> input_files;
 159   g_scheduler->input_file_manager()->GetAllPhysicalInputFileNames(&input_files);
 160   for (const auto& input_file : input_files)
 161     dep_out_ << " " << FilePathToUTF8(input_file);
 162
 163   // Other files read by the build.
 164   std::vector<base::FilePath> other_files = g_scheduler->GetGenDependencies();
 165   for (const auto& other_file : other_files)
 166     dep_out_ << " " << FilePathToUTF8(other_file);
 167
 168   out_ << std::endl;
 169 }
 170
 171 void NinjaBuildWriter::WriteLinkPool() {
 172   out_ << "pool link_pool\n"
 173        << "  depth = " << default_toolchain_->concurrent_links() << std::endl
 174        << std::endl;
 175 }
 176
 177 void NinjaBuildWriter::WriteSubninjas() {
 178   for (const auto& elem : all_settings_) {
 179     out_ << "subninja ";
 180     path_output_.WriteFile(out_, GetNinjaFileForToolchain(elem));
 181     out_ << std::endl;
 182   }
 183   out_ << std::endl;
 184 }
 185
 186 bool NinjaBuildWriter::WritePhonyAndAllRules(Err* err) {
 187   std::string all_rules;
 188
 189   // Track rules as we generate them so we don't accidentally write a phony
 190   // rule that collides with something else.
 191   // GN internally generates an "all" target, so don't duplicate it.
 192   std::set<std::string> written_rules;
 193   written_rules.insert("all");
 194
 195   // Write phony rules for all uniquely-named targets in the default toolchain.
 196   // Don't do other toolchains or we'll get naming conflicts, and if the name
 197   // isn't unique, also skip it. The exception is for the toplevel targets
 198   // which we also find.
 199   std::map<std::string, int> small_name_count;
 200   std::map<std::string, int> exe_count;
 201   std::vector<const Target*> toplevel_targets;
 202   base::hash_set<std::string> target_files;
 203   for (const auto& target : default_toolchain_targets_) {
 204     const Label& label = target->label();
 205     small_name_count[label.name()]++;
 206
 207     // Look for targets with a name of the form
 208     //   dir = "//foo/", name = "foo"
 209     // i.e. where the target name matches the top level directory. We will
 210     // always write phony rules for these even if there is another target with
 211     // the same short name.
 212     const std::string& dir_string = label.dir().value();
 213     if (dir_string.size() == label.name().size() + 3 &&  // Size matches.
 214         dir_string[0] == '/' && dir_string[1] == '/' &&  // "//" at beginning.
 215         dir_string[dir_string.size() - 1] == '/' &&  // "/" at end.
 216         dir_string.compare(2, label.name().size(), label.name()) == 0)
 217       toplevel_targets.push_back(target);
 218
 219     // Look for executables; later we will generate phony rules for them
 220     // even if there are non-executable targets with the same name.
 221     if (target->output_type() == Target::EXECUTABLE)
 222       exe_count[label.name()]++;
 223
 224     // Add the files to the list of generated targets so we don't write phony
 225     // rules that collide.
 226     std::string target_file(target->dependency_output_file().value());
 227     NormalizePath(&target_file);
 228     written_rules.insert(target_file);
 229   }
 230
 231   for (const auto& target : default_toolchain_targets_) {
 232     const Label& label = target->label();
 233     OutputFile target_file(target->dependency_output_file());
 234     // The output files may have leading "./" so normalize those away.
 235     NormalizePath(&target_file.value());
 236     if (!target_files.insert(target_file.value()).second) {
 237       *err = Err(Location(), "Duplicate rules for " + target_file.value());
 238       return false;
 239     }
 240
 241     // Write the long name "foo/bar:baz" for the target "//foo/bar:baz".
 242     std::string long_name = label.GetUserVisibleName(false);
 243     base::TrimString(long_name, "/", &long_name);
 244     WritePhonyRule(target, target_file, long_name, &written_rules);
 245
 246     // Write the directory name with no target name if they match
 247     // (e.g. "//foo/bar:bar" -> "foo/bar").
 248     if (FindLastDirComponent(label.dir()) == label.name()) {
 249       std::string medium_name =  DirectoryWithNoLastSlash(label.dir());
 250       base::TrimString(medium_name, "/", &medium_name);
 251       // That may have generated a name the same as the short name of the
 252       // target which we already wrote.
 253       if (medium_name != label.name())
 254         WritePhonyRule(target, target_file, medium_name, &written_rules);
 255     }
 256
 257     // Write short names for ones which are either completely unique or there
 258     // at least only one of them in the default toolchain that is an exe.
 259     if (small_name_count[label.name()] == 1 ||
 260         (target->output_type() == Target::EXECUTABLE &&
 261          exe_count[label.name()] == 1)) {
 262       WritePhonyRule(target, target_file, label.name(), &written_rules);
 263     }
 264
 265     if (!all_rules.empty())
 266       all_rules.append(" $\n    ");
 267     all_rules.append(target_file.value());
 268   }
 269
 270   // Pick up phony rules for the toplevel targets with non-unique names (which
 271   // would have been skipped in the above loop).
 272   for (const auto& toplevel_target : toplevel_targets) {
 273     if (small_name_count[toplevel_target->label().name()] > 1) {
 274       WritePhonyRule(toplevel_target, toplevel_target->dependency_output_file(),
 275                      toplevel_target->label().name(), &written_rules);
 276     }
 277   }
 278
 279   // Figure out if the BUILD file wants to declare a custom "default"
 280   // target (rather than building 'all' by default). By convention
 281   // we use group("default") but it doesn't have to be a group.
 282   bool default_target_exists = false;
 283   for (const auto& target : default_toolchain_targets_) {
 284     const Label& label = target->label();
 285     if (label.dir().value() == "//" && label.name() == "default")
 286       default_target_exists = true;
 287   }
 288
 289   if (!all_rules.empty()) {
 290     out_ << "\nbuild all: phony " << all_rules << std::endl;
 291   }
 292
 293   if (default_target_exists) {
 294     out_ << "default default" << std::endl;
 295   } else if (!all_rules.empty()) {
 296     out_ << "default all" << std::endl;
 297   }
 298
 299   return true;
 300 }
 301
 302 void NinjaBuildWriter::WritePhonyRule(const Target* target,
 303                                       const OutputFile& target_file,
 304                                       const std::string& phony_name,
 305                                       std::set<std::string>* written_rules) {
 306   if (target_file.value() == phony_name)
 307     return;  // No need for a phony rule.
 308
 309   if (written_rules->find(phony_name) != written_rules->end())
 310     return;  // Already exists.
 311   written_rules->insert(phony_name);
 312
 313   EscapeOptions ninja_escape;
 314   ninja_escape.mode = ESCAPE_NINJA;
 315
 316   // Escape for special chars Ninja will handle.
 317   std::string escaped = EscapeString(phony_name, ninja_escape, nullptr);
 318
 319   out_ << "build " << escaped << ": phony ";
 320   path_output_.WriteFile(out_, target_file);
 321   out_ << std::endl;
 322 }