tools/gn/functions_target.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/functions.h"
   6
   7 #include "tools/gn/config_values_generator.h"
   8 #include "tools/gn/err.h"
   9 #include "tools/gn/parse_tree.h"
  10 #include "tools/gn/scope.h"
  11 #include "tools/gn/target_generator.h"
  12 #include "tools/gn/value.h"
  13 #include "tools/gn/variables.h"
  14
  15 #define DEPENDENT_CONFIG_VARS \
  16     "  Dependent configs: all_dependent_configs, public_configs\n"
  17 #define DEPS_VARS \
  18     "  Deps: data_deps, deps, forward_dependent_configs_from, public_deps\n"
  19 #define GENERAL_TARGET_VARS \
  20     "  General: check_includes, configs, data, inputs, output_name,\n" \
  21     "           output_extension, public, sources, testonly, visibility\n"
  22
  23 namespace functions {
  24
  25 namespace {
  26
  27 Value ExecuteGenericTarget(const char* target_type,
  28                            Scope* scope,
  29                            const FunctionCallNode* function,
  30                            const std::vector<Value>& args,
  31                            BlockNode* block,
  32                            Err* err) {
  33   if (!EnsureNotProcessingImport(function, scope, err) ||
  34       !EnsureNotProcessingBuildConfig(function, scope, err))
  35     return Value();
  36   Scope block_scope(scope);
  37   if (!FillTargetBlockScope(scope, function, target_type, block,
  38                             args, &block_scope, err))
  39     return Value();
  40
  41   block->Execute(&block_scope, err);
  42   if (err->has_error())
  43     return Value();
  44
  45   TargetGenerator::GenerateTarget(&block_scope, function, args,
  46                                   target_type, err);
  47   if (err->has_error())
  48     return Value();
  49
  50   block_scope.CheckForUnusedVars(err);
  51   return Value();
  52 }
  53
  54 }  // namespace
  55
  56 // action ----------------------------------------------------------------------
  57
  58 // Common help paragraph on script runtime execution directories.
  59 #define SCRIPT_EXECUTION_CONTEXT \
  60     "  The script will be executed with the given arguments with the current\n"\
  61     "  directory being that of the root build directory. If you pass files\n"\
  62     "  to your script, see \"gn help rebase_path\" for how to convert\n" \
  63     "  file names to be relative to the build directory (file names in the\n" \
  64     "  sources, outputs, and inputs will be all treated as relative to the\n" \
  65     "  current build file and converted as needed automatically).\n"
  66
  67 // Common help paragraph on script output directories.
  68 #define SCRIPT_EXECUTION_OUTPUTS \
  69     "  All output files must be inside the output directory of the build.\n" \
  70     "  You would generally use |$target_out_dir| or |$target_gen_dir| to\n" \
  71     "  reference the output or generated intermediate file directories,\n" \
  72     "  respectively.\n"
  73
  74 #define ACTION_DEPS \
  75     "  The \"deps\" and \"public_deps\" for an action will always be\n" \
  76     "  completed before any part of the action is run so it can depend on\n" \
  77     "  the output of previous steps. The \"data_deps\" will be built if the\n" \
  78     "  action is built, but may not have completed before all steps of the\n" \
  79     "  action are started. This can give additional parallelism in the build\n"\
  80     "  for runtime-only dependencies.\n"
  81
  82 const char kAction[] = "action";
  83 const char kAction_HelpShort[] =
  84     "action: Declare a target that runs a script a single time.";
  85 const char kAction_Help[] =
  86     "action: Declare a target that runs a script a single time.\n"
  87     "\n"
  88     "  This target type allows you to run a script a single time to produce\n"
  89     "  or more output files. If you want to run a script once for each of a\n"
  90     "  set of input files, see \"gn help action_foreach\".\n"
  91     "\n"
  92     "Inputs\n"
  93     "\n"
  94     "  In an action the \"sources\" and \"inputs\" are treated the same:\n"
  95     "  they're both input dependencies on script execution with no special\n"
  96     "  handling. If you want to pass the sources to your script, you must do\n"
  97     "  so explicitly by including them in the \"args\". Note also that this\n"
  98     "  means there is no special handling of paths since GN doesn't know\n"
  99     "  which of the args are paths and not. You will want to use\n"
 100     "  rebase_path() to convert paths to be relative to the root_build_dir.\n"
 101     "\n"
 102     "  You can dynamically write input dependencies (for incremental rebuilds\n"
 103     "  if an input file changes) by writing a depfile when the script is run\n"
 104     "  (see \"gn help depfile\"). This is more flexible than \"inputs\".\n"
 105     "\n"
 106     "  It is recommended you put inputs to your script in the \"sources\"\n"
 107     "  variable, and stuff like other Python files required to run your\n"
 108     "  script in the \"inputs\" variable.\n"
 109     "\n"
 110     ACTION_DEPS
 111     "\n"
 112     "Outputs\n"
 113     "\n"
 114     "  You should specify files created by your script by specifying them in\n"
 115     "  the \"outputs\".\n"
 116     "\n"
 117     SCRIPT_EXECUTION_CONTEXT
 118     "\n"
 119     "File name handling\n"
 120     "\n"
 121     SCRIPT_EXECUTION_OUTPUTS
 122     "\n"
 123     "Variables\n"
 124     "\n"
 125     "  args, data, data_deps, depfile, deps, outputs*, script*,\n"
 126     "  inputs, sources\n"
 127     "  * = required\n"
 128     "\n"
 129     "Example\n"
 130     "\n"
 131     "  action(\"run_this_guy_once\") {\n"
 132     "    script = \"doprocessing.py\"\n"
 133     "    sources = [ \"my_configuration.txt\" ]\n"
 134     "    outputs = [ \"$target_gen_dir/insightful_output.txt\" ]\n"
 135     "\n"
 136     "    # Our script imports this Python file so we want to rebuild if it\n"
 137     "    # changes.\n"
 138     "    inputs = [ \"helper_library.py\" ]\n"
 139     "\n"
 140     "    # Note that we have to manually pass the sources to our script if\n"
 141     "    # the script needs them as inputs.\n"
 142     "    args = [ \"--out\", rebase_path(target_gen_dir, root_build_dir) ] +\n"
 143     "           rebase_path(sources, root_build_dir)\n"
 144     "  }\n";
 145
 146 Value RunAction(Scope* scope,
 147                 const FunctionCallNode* function,
 148                 const std::vector<Value>& args,
 149                 BlockNode* block,
 150                 Err* err) {
 151   return ExecuteGenericTarget(functions::kAction, scope, function, args,
 152                               block, err);
 153 }
 154
 155 // action_foreach --------------------------------------------------------------
 156
 157 const char kActionForEach[] = "action_foreach";
 158 const char kActionForEach_HelpShort[] =
 159     "action_foreach: Declare a target that runs a script over a set of files.";
 160 const char kActionForEach_Help[] =
 161     "action_foreach: Declare a target that runs a script over a set of files.\n"
 162     "\n"
 163     "  This target type allows you to run a script once-per-file over a set\n"
 164     "  of sources. If you want to run a script once that takes many files as\n"
 165     "  input, see \"gn help action\".\n"
 166     "\n"
 167     "Inputs\n"
 168     "\n"
 169     "  The script will be run once per file in the \"sources\" variable. The\n"
 170     "  \"outputs\" variable should specify one or more files with a source\n"
 171     "  expansion pattern in it (see \"gn help source_expansion\"). The output\n"
 172     "  file(s) for each script invocation should be unique. Normally you\n"
 173     "  use \"{{source_name_part}}\" in each output file.\n"
 174     "\n"
 175     "  If your script takes additional data as input, such as a shared\n"
 176     "  configuration file or a Python module it uses, those files should be\n"
 177     "  listed in the \"inputs\" variable. These files are treated as\n"
 178     "  dependencies of each script invocation.\n"
 179     "\n"
 180     "  You can dynamically write input dependencies (for incremental rebuilds\n"
 181     "  if an input file changes) by writing a depfile when the script is run\n"
 182     "  (see \"gn help depfile\"). This is more flexible than \"inputs\".\n"
 183     "\n"
 184     ACTION_DEPS
 185     "\n"
 186     "Outputs\n"
 187     "\n"
 188     SCRIPT_EXECUTION_CONTEXT
 189     "\n"
 190     "File name handling\n"
 191     "\n"
 192     SCRIPT_EXECUTION_OUTPUTS
 193     "\n"
 194     "Variables\n"
 195     "\n"
 196     "  args, data, data_deps, depfile, deps, outputs*, script*,\n"
 197     "  inputs, sources*\n"
 198     "  * = required\n"
 199     "\n"
 200     "Example\n"
 201     "\n"
 202     "  # Runs the script over each IDL file. The IDL script will generate\n"
 203     "  # both a .cc and a .h file for each input.\n"
 204     "  action_foreach(\"my_idl\") {\n"
 205     "    script = \"idl_processor.py\"\n"
 206     "    sources = [ \"foo.idl\", \"bar.idl\" ]\n"
 207     "\n"
 208     "    # Our script reads this file each time, so we need to list is as a\n"
 209     "    # dependency so we can rebuild if it changes.\n"
 210     "    inputs = [ \"my_configuration.txt\" ]\n"
 211     "\n"
 212     "    # Transformation from source file name to output file names.\n"
 213     "    outputs = [ \"$target_gen_dir/{{source_name_part}}.h\",\n"
 214     "                \"$target_gen_dir/{{source_name_part}}.cc\" ]\n"
 215     "\n"
 216     "    # Note that since \"args\" is opaque to GN, if you specify paths\n"
 217     "    # here, you will need to convert it to be relative to the build\n"
 218     "    # directory using \"rebase_path()\".\n"
 219     "    args = [\n"
 220     "      \"{{source}}\",\n"
 221     "      \"-o\",\n"
 222     "      rebase_path(relative_target_gen_dir, root_build_dir) +\n"
 223     "        \"/{{source_name_part}}.h\" ]\n"
 224     "  }\n"
 225     "\n";
 226 Value RunActionForEach(Scope* scope,
 227                        const FunctionCallNode* function,
 228                        const std::vector<Value>& args,
 229                        BlockNode* block,
 230                        Err* err) {
 231   return ExecuteGenericTarget(functions::kActionForEach, scope, function, args,
 232                               block, err);
 233 }
 234
 235 // copy ------------------------------------------------------------------------
 236
 237 const char kCopy[] = "copy";
 238 const char kCopy_HelpShort[] =
 239     "copy: Declare a target that copies files.";
 240 const char kCopy_Help[] =
 241     "copy: Declare a target that copies files.\n"
 242     "\n"
 243     "File name handling\n"
 244     "\n"
 245     "  All output files must be inside the output directory of the build.\n"
 246     "  You would generally use |$target_out_dir| or |$target_gen_dir| to\n"
 247     "  reference the output or generated intermediate file directories,\n"
 248     "  respectively.\n"
 249     "\n"
 250     "  Both \"sources\" and \"outputs\" must be specified. Sources can\n"
 251     "  as many files as you want, but there can only be one item in the\n"
 252     "  outputs list (plural is used for the name for consistency with\n"
 253     "  other target types).\n"
 254     "\n"
 255     "  If there is more than one source file, your output name should specify\n"
 256     "  a mapping from each source files to output file names using source\n"
 257     "  expansion (see \"gn help source_expansion\"). The placeholders will\n"
 258     "  will look like \"{{source_name_part}}\", for example.\n"
 259     "\n"
 260     "Examples\n"
 261     "\n"
 262     "  # Write a rule that copies a checked-in DLL to the output directory.\n"
 263     "  copy(\"mydll\") {\n"
 264     "    sources = [ \"mydll.dll\" ]\n"
 265     "    outputs = [ \"$target_out_dir/mydll.dll\" ]\n"
 266     "  }\n"
 267     "\n"
 268     "  # Write a rule to copy several files to the target generated files\n"
 269     "  # directory.\n"
 270     "  copy(\"myfiles\") {\n"
 271     "    sources = [ \"data1.dat\", \"data2.dat\", \"data3.dat\" ]\n"
 272     "\n"
 273     "    # Use source expansion to generate output files with the\n"
 274     "    # corresponding file names in the gen dir. This will just copy each\n"
 275     "    # file.\n"
 276     "    outputs = [ \"$target_gen_dir/{{source_file_part}}\" ]\n"
 277     "  }\n";
 278
 279 Value RunCopy(const FunctionCallNode* function,
 280               const std::vector<Value>& args,
 281               Scope* scope,
 282               Err* err) {
 283   if (!EnsureNotProcessingImport(function, scope, err) ||
 284       !EnsureNotProcessingBuildConfig(function, scope, err))
 285     return Value();
 286   TargetGenerator::GenerateTarget(scope, function, args, functions::kCopy, err);
 287   return Value();
 288 }
 289
 290 // executable ------------------------------------------------------------------
 291
 292 const char kExecutable[] = "executable";
 293 const char kExecutable_HelpShort[] =
 294     "executable: Declare an executable target.";
 295 const char kExecutable_Help[] =
 296     "executable: Declare an executable target.\n"
 297     "\n"
 298     "Variables\n"
 299     "\n"
 300     CONFIG_VALUES_VARS_HELP
 301     DEPS_VARS
 302     DEPENDENT_CONFIG_VARS
 303     GENERAL_TARGET_VARS;
 304
 305 Value RunExecutable(Scope* scope,
 306                     const FunctionCallNode* function,
 307                     const std::vector<Value>& args,
 308                     BlockNode* block,
 309                     Err* err) {
 310   return ExecuteGenericTarget(functions::kExecutable, scope, function, args,
 311                               block, err);
 312 }
 313
 314 // group -----------------------------------------------------------------------
 315
 316 const char kGroup[] = "group";
 317 const char kGroup_HelpShort[] =
 318     "group: Declare a named group of targets.";
 319 const char kGroup_Help[] =
 320     "group: Declare a named group of targets.\n"
 321     "\n"
 322     "  This target type allows you to create meta-targets that just collect a\n"
 323     "  set of dependencies into one named target. Groups can additionally\n"
 324     "  specify configs that apply to their dependents.\n"
 325     "\n"
 326     "  Depending on a group is exactly like depending directly on that\n"
 327     "  group's deps. Direct dependent configs will get automatically\n"
 328     "  forwarded through the group so you shouldn't need to use\n"
 329     "  \"forward_dependent_configs_from.\n"
 330     "\n"
 331     "Variables\n"
 332     "\n"
 333     DEPS_VARS
 334     DEPENDENT_CONFIG_VARS
 335     "\n"
 336     "Example\n"
 337     "\n"
 338     "  group(\"all\") {\n"
 339     "    deps = [\n"
 340     "      \"//project:runner\",\n"
 341     "      \"//project:unit_tests\",\n"
 342     "    ]\n"
 343     "  }\n";
 344
 345 Value RunGroup(Scope* scope,
 346                const FunctionCallNode* function,
 347                const std::vector<Value>& args,
 348                BlockNode* block,
 349                Err* err) {
 350   return ExecuteGenericTarget(functions::kGroup, scope, function, args,
 351                               block, err);
 352 }
 353
 354 // shared_library --------------------------------------------------------------
 355
 356 const char kSharedLibrary[] = "shared_library";
 357 const char kSharedLibrary_HelpShort[] =
 358     "shared_library: Declare a shared library target.";
 359 const char kSharedLibrary_Help[] =
 360     "shared_library: Declare a shared library target.\n"
 361     "\n"
 362     "  A shared library will be specified on the linker line for targets\n"
 363     "  listing the shared library in its \"deps\". If you don't want this\n"
 364     "  (say you dynamically load the library at runtime), then you should\n"
 365     "  depend on the shared library via \"data_deps\" instead.\n"
 366     "\n"
 367     "Variables\n"
 368     "\n"
 369     CONFIG_VALUES_VARS_HELP
 370     DEPS_VARS
 371     DEPENDENT_CONFIG_VARS
 372     GENERAL_TARGET_VARS;
 373
 374 Value RunSharedLibrary(Scope* scope,
 375                        const FunctionCallNode* function,
 376                        const std::vector<Value>& args,
 377                        BlockNode* block,
 378                        Err* err) {
 379   return ExecuteGenericTarget(functions::kSharedLibrary, scope, function, args,
 380                               block, err);
 381 }
 382
 383 // source_set ------------------------------------------------------------------
 384
 385 extern const char kSourceSet[] = "source_set";
 386 extern const char kSourceSet_HelpShort[] =
 387     "source_set: Declare a source set target.";
 388 extern const char kSourceSet_Help[] =
 389     "source_set: Declare a source set target.\n"
 390     "\n"
 391     "  A source set is a collection of sources that get compiled, but are not\n"
 392     "  linked to produce any kind of library. Instead, the resulting object\n"
 393     "  files are implicitly added to the linker line of all targets that\n"
 394     "  depend on the source set.\n"
 395     "\n"
 396     "  In most cases, a source set will behave like a static library, except\n"
 397     "  no actual library file will be produced. This will make the build go\n"
 398     "  a little faster by skipping creation of a large static library, while\n"
 399     "  maintaining the organizational benefits of focused build targets.\n"
 400     "\n"
 401     "  The main difference between a source set and a static library is\n"
 402     "  around handling of exported symbols. Most linkers assume declaring\n"
 403     "  a function exported means exported from the static library. The linker\n"
 404     "  can then do dead code elimination to delete code not reachable from\n"
 405     "  exported functions.\n"
 406     "\n"
 407     "  A source set will not do this code elimination since there is no link\n"
 408     "  step. This allows you to link many sources sets into a shared library\n"
 409     "  and have the \"exported symbol\" notation indicate \"export from the\n"
 410     "  final shared library and not from the intermediate targets.\" There is\n"
 411     "  no way to express this concept when linking multiple static libraries\n"
 412     "  into a shared library.\n"
 413     "\n"
 414     "Variables\n"
 415     "\n"
 416     CONFIG_VALUES_VARS_HELP
 417     DEPS_VARS
 418     DEPENDENT_CONFIG_VARS
 419     GENERAL_TARGET_VARS;
 420
 421 Value RunSourceSet(Scope* scope,
 422                    const FunctionCallNode* function,
 423                    const std::vector<Value>& args,
 424                    BlockNode* block,
 425                    Err* err) {
 426   return ExecuteGenericTarget(functions::kSourceSet, scope, function, args,
 427                               block, err);
 428 }
 429
 430 // static_library --------------------------------------------------------------
 431
 432 const char kStaticLibrary[] = "static_library";
 433 const char kStaticLibrary_HelpShort[] =
 434     "static_library: Declare a static library target.";
 435 const char kStaticLibrary_Help[] =
 436     "static_library: Declare a static library target.\n"
 437     "\n"
 438     "  Make a \".a\" / \".lib\" file.\n"
 439     "\n"
 440     "  If you only need the static library for intermediate results in the\n"
 441     "  build, you should consider a source_set instead since it will skip\n"
 442     "  the (potentially slow) step of creating the intermediate library file.\n"
 443     "\n"
 444     "Variables\n"
 445     "\n"
 446     CONFIG_VALUES_VARS_HELP
 447     DEPS_VARS
 448     DEPENDENT_CONFIG_VARS
 449     GENERAL_TARGET_VARS;
 450
 451 Value RunStaticLibrary(Scope* scope,
 452                        const FunctionCallNode* function,
 453                        const std::vector<Value>& args,
 454                        BlockNode* block,
 455                        Err* err) {
 456   return ExecuteGenericTarget(functions::kStaticLibrary, scope, function, args,
 457                               block, err);
 458 }
 459
 460 }  // namespace functions