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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/variables.h"
6 
7 namespace variables {
8 
9 // Built-in variables ----------------------------------------------------------
10 
11 const char kComponentMode[] = "component_mode";
12 const char kComponentMode_HelpShort[] =
13     "component_mode: [string] Specifies the meaning of the component() call.";
14 const char kComponentMode_Help[] =
15     "component_mode: Specifies the meaning of the component() call.\n"
16     "\n"
17     "  This value is looked up whenever a \"component\" target type is\n"
18     "  encountered. The value controls whether the given target is a shared\n"
19     "  or a static library.\n"
20     "\n"
21     "  The initial value will be empty, which will cause a call to\n"
22     "  component() to throw an error. Typically this value will be set in the\n"
23     "  build config script.\n"
24     "\n"
25     "Possible values:\n"
26     "  - \"shared_library\"\n"
27     "  - \"source_set\"\n"
28     "  - \"static_library\"\n";
29 
30 const char kCpuArch[] = "cpu_arch";
31 const char kCpuArch_HelpShort[] =
32     "cpu_arch: [string] Current processor architecture.";
33 const char kCpuArch_Help[] =
34     "cpu_arch: Current processor architecture.\n"
35     "\n"
36     "  The initial value is based on the current architecture of the host\n"
37     "  system. However, the build configuration can set this to any value.\n"
38     "\n"
39     "  This value is not used internally by GN for any purpose, so you can\n"
40     "  set it to whatever value is relevant to your build.\n"
41     "\n"
42     "Possible initial values set by GN:\n"
43     "  - \"x86\"\n"
44     "  - \"x64\"\n"
45     "  - \"arm\"\n";
46 
47 const char kCurrentToolchain[] = "current_toolchain";
48 const char kCurrentToolchain_HelpShort[] =
49     "current_toolchain: [string] Label of the current toolchain.";
50 const char kCurrentToolchain_Help[] =
51     "current_toolchain: Label of the current toolchain.\n"
52     "\n"
53     "  A fully-qualified label representing the current toolchain. You can\n"
54     "  use this to make toolchain-related decisions in the build. See also\n"
55     "  \"default_toolchain\".\n"
56     "\n"
57     "Example:\n"
58     "\n"
59     "  if (current_toolchain == \"//build:64_bit_toolchain\") {\n"
60     "    executable(\"output_thats_64_bit_only\") {\n"
61     "      ...\n";
62 
63 const char kBuildCpuArch[] = "build_cpu_arch";
64 const char kBuildCpuArch_HelpShort[] =
65     "build_cpu_arch: [string] The default value for the \"cpu_arch\" "
66     "variable.";
67 const char kBuildCpuArch_Help[] =
68     "build_cpu_arch: The default value for the \"cpu_arch\" variable.\n"
69     "\n"
70     "  This value has the same definition as \"cpu_arch\" (see\n"
71     "  \"gn help cpu_arch\") but should be treated as read-only. This is so\n"
72     "  the build can override the \"cpu_arch\" variable for doing\n"
73     "  cross-compiles, but can still access the host build system's CPU\n"
74     "  architecture.\n";
75 
76 const char kBuildOs[] = "build_os";
77 const char kBuildOs_HelpShort[] =
78     "build_os: [string] The default value for the \"os\" variable.";
79 const char kBuildOs_Help[] =
80     "build_os: [string] The default value for the \"os\" variable.\n"
81     "\n"
82     "  This value has the same definition as \"os\" (see \"gn help os\") but\n"
83     "  should be treated as read-only. This is so the build can override\n"
84     "  the \"os\" variable for doing cross-compiles, but can still access\n"
85     "  the host build system's operating system type.\n";
86 
87 const char kDefaultToolchain[] = "default_toolchain";
88 const char kDefaultToolchain_HelpShort[] =
89     "default_toolchain: [string] Label of the default toolchain.";
90 const char kDefaultToolchain_Help[] =
91     "default_toolchain: [string] Label of the default toolchain.\n"
92     "\n"
93     "  A fully-qualified label representing the default toolchain, which may\n"
94     "  not necessarily be the current one (see \"current_toolchain\").\n";
95 
96 const char kOs[] = "os";
97 const char kOs_HelpShort[] =
98     "os: [string] Indicates the operating system of the current build.";
99 const char kOs_Help[] =
100     "os: Indicates the operating system of the current build."
101     "\n"
102     "  This value is set by default based on the current host operating\n"
103     "  system. The build configuration can override the value to anything\n"
104     "  it wants, or it can be set via the build arguments on the command\n"
105     "  line.\n"
106     "\n"
107     "  If you want to know the default value without any overrides, you can\n"
108     "  use \"default_os\" (see \"gn help default_os\").\n"
109     "\n"
110     "  Note that this returns the most specific value. So even though\n"
111     "  Android and ChromeOS are both Linux, the more specific value will\n"
112     "  be returned.\n"
113     "\n"
114     "Some possible values:\n"
115     "  - \"amiga\"\n"
116     "  - \"android\"\n"
117     "  - \"chromeos\"\n"
118     "  - \"ios\"\n"
119     "  - \"linux\"\n"
120     "  - \"mac\"\n"
121     "  - \"win\"\n";
122 
123 const char kPythonPath[] = "python_path";
124 const char kPythonPath_HelpShort[] =
125     "python_path: [string] Absolute path of Python.";
126 const char kPythonPath_Help[] =
127     "python_path: Absolute path of Python.\n"
128     "\n"
129     "  Normally used in toolchain definitions if running some command\n"
130     "  requires Python. You will normally not need this when invoking scripts\n"
131     "  since GN automatically finds it for you.\n";
132 
133 const char kRootBuildDir[] = "root_build_dir";
134 const char kRootBuildDir_HelpShort[] =
135   "root_build_dir: [string] Directory where build commands are run.";
136 const char kRootBuildDir_Help[] =
137   "root_build_dir: [string] Directory where build commands are run.\n"
138   "\n"
139   "  This is the root build output directory which will be the current\n"
140   "  directory when executing all compilers and scripts.\n"
141   "\n"
142   "  Most often this is used with rebase_path (see \"gn help rebase_path\")\n"
143   "  to convert arguments to be relative to a script's current directory.\n";
144 
145 const char kRootGenDir[] = "root_gen_dir";
146 const char kRootGenDir_HelpShort[] =
147     "root_gen_dir: [string] Directory for the toolchain's generated files.";
148 const char kRootGenDir_Help[] =
149     "root_gen_dir: Directory for the toolchain's generated files.\n"
150     "\n"
151     "  Absolute path to the root of the generated output directory tree for\n"
152     "  the current toolchain. An example value might be \"//out/Debug/gen\".\n"
153     "  It will not have a trailing slash.\n"
154     "\n"
155     "  This is primarily useful for setting up include paths for generated\n"
156     "  files. If you are passing this to a script, you will want to pass it\n"
157     "  through to_build_path() (see \"gn help to_build_path\") to convert it\n"
158     "  to be relative to the build directory.\n"
159     "\n"
160     "  See also \"target_gen_dir\" which is usually a better location for\n"
161     "  generated files. It will be inside the root generated dir.\n";
162 
163 const char kRootOutDir[] = "root_out_dir";
164 const char kRootOutDir_HelpShort[] =
165     "root_out_dir: [string] Root directory for toolchain output files.";
166 const char kRootOutDir_Help[] =
167     "root_out_dir: [string] Root directory for toolchain output files.\n"
168     "\n"
169     "  Absolute path to the root of the output directory tree for the current\n"
170     "  toolchain. An example value might be \"//out/Debug/gen\". It will not\n"
171     "  have a trailing slash.\n"
172     "\n"
173     "  This is primarily useful for setting up script calls. If you are\n"
174     "  passing this to a script, you will want to pass it through\n"
175     "  to_build_path() (see \"gn help to_build_path\") to convert it\n"
176     "  to be relative to the build directory.\n"
177     "\n"
178     "  See also \"target_out_dir\" which is usually a better location for\n"
179     "  output files. It will be inside the root output dir.\n"
180     "\n"
181     "Example:\n"
182     "\n"
183     "  custom(\"myscript\") {\n"
184     "    # Pass the output dir to the script.\n"
185     "    args = [ \"-o\", to_build_path(root_out_dir) ]\n"
186     "  }\n";
187 
188 const char kTargetGenDir[] = "target_gen_dir";
189 const char kTargetGenDir_HelpShort[] =
190     "target_gen_dir: [string] Directory for a target's generated files.";
191 const char kTargetGenDir_Help[] =
192     "target_gen_dir: Directory for a target's generated files.\n"
193     "\n"
194     "  Absolute path to the target's generated file directory. If your\n"
195     "  current target is in \"//tools/doom_melon\" then this value might be\n"
196     "  \"//out/Debug/gen/tools/doom_melon\". It will not have a trailing\n"
197     "  slash.\n"
198     "\n"
199     "  This is primarily useful for setting up include paths for generated\n"
200     "  files. If you are passing this to a script, you will want to pass it\n"
201     "  through to_build_path() (see \"gn help to_build_path\") to convert it\n"
202     "  to be relative to the build directory.\n"
203     "\n"
204     "  See also \"gn help root_gen_dir\".\n"
205     "\n"
206     "Example:\n"
207     "\n"
208     "  custom(\"myscript\") {\n"
209     "    # Pass the generated output dir to the script.\n"
210     "    args = [ \"-o\", to_build_path(target_gen_dir) ]\n"
211     "  }\n";
212 
213 const char kTargetOutDir[] = "target_out_dir";
214 const char kTargetOutDir_HelpShort[] =
215     "target_out_dir: [string] Directory for target output files.";
216 const char kTargetOutDir_Help[] =
217     "target_out_dir: [string] Directory for target output files."
218     "\n"
219     "  Absolute path to the target's generated file directory. If your\n"
220     "  current target is in \"//tools/doom_melon\" then this value might be\n"
221     "  \"//out/Debug/obj/tools/doom_melon\". It will not have a trailing\n"
222     "  slash.\n"
223     "\n"
224     "  This is primarily useful for setting up arguments for calling\n"
225     "  scripts. If you are passing this to a script, you will want to pass it\n"
226     "  through to_build_path() (see \"gn help to_build_path\") to convert it\n"
227     "  to be relative to the build directory.\n"
228     "\n"
229     "  See also \"gn help root_out_dir\".\n"
230     "\n"
231     "Example:\n"
232     "\n"
233     "  custom(\"myscript\") {\n"
234     "    # Pass the output dir to the script.\n"
235     "    args = [ \"-o\", to_build_path(target_out_dir) ]\n"
236     "  }\n";
237 
238 // Target variables ------------------------------------------------------------
239 
240 const char kAllDependentConfigs[] = "all_dependent_configs";
241 const char kAllDependentConfigs_HelpShort[] =
242     "all_dependent_configs: [label list] Configs to be forced on dependents.";
243 const char kAllDependentConfigs_Help[] =
244     "all_dependent_configs: Configs to be forced on dependents.\n"
245     "\n"
246     "  A list of config labels.\n"
247     "\n"
248     "  All targets depending on this one, and recursively, all targets\n"
249     "  depending on those, will have the configs listed in this variable\n"
250     "  added to them. These configs will also apply to the current target.\n"
251     "\n"
252     "  This addition happens in a second phase once a target and all of its\n"
253     "  dependencies have been resolved. Therefore, a target will not see\n"
254     "  these force-added configs in their \"configs\" variable while the\n"
255     "  script is running, and then can not be removed. As a result, this\n"
256     "  capability should generally only be used to add defines and include\n"
257     "  directories necessary to compile a target's headers.\n"
258     "\n"
259     "  See also \"direct_dependent_configs\".\n";
260 
261 const char kArgs[] = "args";
262 const char kArgs_HelpShort[] =
263     "args: [string list] Arguments passed to a custom script.";
264 const char kArgs_Help[] =
265     "args: Arguments passed to a custom script.\n"
266     "\n"
267     "  For custom script targets, args is the list of arguments to pass\n"
268     "  to the script. Typically you would use source expansion (see\n"
269     "  \"gn help source_expansion\") to insert the source file names.\n"
270     "\n"
271     "  See also \"gn help custom\".\n";
272 
273 const char kCflags[] = "cflags";
274 const char kCflags_HelpShort[] =
275     "cflags: [string list] Flags passed to all C compiler variants.";
276 // Avoid writing long help for each variant.
277 #define COMMON_FLAGS_HELP \
278     "\n"\
279     "  Flags are never quoted. If your flag includes a string that must be\n"\
280     "  quoted, you must do it yourself. This also means that you can\n"\
281     "  specify more than one flag in a string if necessary (\"--foo --bar\")\n"\
282     "  and have them be seen as separate by the tool.\n"
283 const char kCommonCflagsHelp[] =
284     "cflags*: Flags passed to the C compiler.\n"
285     "\n"
286     "  A list of strings.\n"
287     "\n"
288     "  \"cflags\" are passed to all invocations of the C, C++, Objective C,\n"
289     "  and Objective C++ compilers.\n"
290     "\n"
291     "  To target one of these variants individually, use \"cflags_c\",\n"
292     "  \"cflags_cc\", \"cflags_objc\", and \"cflags_objcc\", respectively.\n"
293     "  These variant-specific versions will be appended to the \"cflags\".\n"
294     COMMON_FLAGS_HELP;
295 const char* kCflags_Help = kCommonCflagsHelp;
296 
297 const char kCflagsC[] = "cflags_c";
298 const char kCflagsC_HelpShort[] =
299     "cflags_c: [string list] Flags passed to the C compiler.";
300 const char* kCflagsC_Help = kCommonCflagsHelp;
301 
302 const char kCflagsCC[] = "cflags_cc";
303 const char kCflagsCC_HelpShort[] =
304     "cflags_cc: [string list] Flags passed to the C++ compiler.";
305 const char* kCflagsCC_Help = kCommonCflagsHelp;
306 
307 const char kCflagsObjC[] = "cflags_objc";
308 const char kCflagsObjC_HelpShort[] =
309     "cflags_objc: [string list] Flags passed to the Objective C compiler.";
310 const char* kCflagsObjC_Help = kCommonCflagsHelp;
311 
312 const char kCflagsObjCC[] = "cflags_objcc";
313 const char kCflagsObjCC_HelpShort[] =
314     "cflags_objcc: [string list] Flags passed to the Objective C++ compiler.";
315 const char* kCflagsObjCC_Help = kCommonCflagsHelp;
316 
317 const char kConfigs[] = "configs";
318 const char kConfigs_HelpShort[] =
319     "configs: [label list] Configs applying to this target.";
320 const char kConfigs_Help[] =
321     "configs: Configs applying to this target.\n"
322     "\n"
323     "  A list of config labels.\n"
324     "\n"
325     "  The include_dirs, defines, etc. in each config are appended in the\n"
326     "  order they appear to the compile command for each file in the target.\n"
327     "  They will appear after the include_dirs, defines, etc. that the target\n"
328     "  sets directly.\n"
329     "\n"
330     "  The build configuration script will generally set up the default\n"
331     "  configs applying to a given target type (see \"set_defaults\").\n"
332     "  When a target is being defined, it can add to or remove from this\n"
333     "  list.\n"
334     "\n"
335     "Example:\n"
336     "  static_library(\"foo\") {\n"
337     "    configs -= \"//build:no_rtti\"  # Don't use the default RTTI config.\n"
338     "    configs += \":mysettings\"      # Add some of our own settings.\n"
339     "  }\n";
340 
341 const char kData[] = "data";
342 const char kData_HelpShort[] =
343     "data: [file list] Runtime data file dependencies.";
344 const char kData_Help[] =
345     "data: Runtime data file dependencies.\n"
346     "\n"
347     "  Lists files required to run the given target. These are typically\n"
348     "  data files.\n"
349     "\n"
350     "  Appearing in the \"data\" section does not imply any special handling\n"
351     "  such as copying them to the output directory. This is just used for\n"
352     "  declaring runtime dependencies. There currently isn't a good use for\n"
353     "  these but it is envisioned that test data can be listed here for use\n"
354     "  running automated tests.\n"
355     "\n"
356     "  See also \"gn help source_prereqs\" and \"gn help datadeps\", both of\n"
357     "  which actually affect the build in concrete ways.\n";
358 
359 const char kDatadeps[] = "datadeps";
360 const char kDatadeps_HelpShort[] =
361     "datadeps: [label list] Non-linked dependencies.";
362 const char kDatadeps_Help[] =
363     "datadeps: Non-linked dependencies.\n"
364     "\n"
365     "  A list of target labels.\n"
366     "\n"
367     "  Specifies dependencies of a target that are not actually linked into\n"
368     "  the current target. Such dependencies will built and will be available\n"
369     "  at runtime.\n"
370     "\n"
371     "  This is normally used for things like plugins or helper programs that\n"
372     "  a target needs at runtime.\n"
373     "\n"
374     "  See also \"gn help deps\" and \"gn help data\".\n"
375     "\n"
376     "Example:\n"
377     "  executable(\"foo\") {\n"
378     "    deps = [ \"//base\" ]\n"
379     "    datadeps = [ \"//plugins:my_runtime_plugin\" ]\n"
380     "  }\n";
381 
382 const char kDefines[] = "defines";
383 const char kDefines_HelpShort[] =
384     "defines: [string list] C preprocessor defines.";
385 const char kDefines_Help[] =
386     "defines: C preprocessor defines.\n"
387     "\n"
388     "  A list of strings\n"
389     "\n"
390     "  These strings will be passed to the C/C++ compiler as #defines. The\n"
391     "  strings may or may not include an \"=\" to assign a value.\n"
392     "\n"
393     "Example:\n"
394     "  defines = [ \"AWESOME_FEATURE\", \"LOG_LEVEL=3\" ]\n";
395 
396 const char kDepfile[] = "depfile";
397 const char kDepfile_HelpShort[] =
398     "depfile: [string] File name for input dependencies for custom targets.";
399 const char kDepfile_Help[] =
400     "depfile: [string] File name for input dependencies for custom targets.\n"
401     "\n"
402     "  If nonempty, this string specifies that the current \"custom\" target\n"
403     "  will generate the given \".d\" file containing the dependencies of the\n"
404     "  input. Empty or unset means that the script doesn't generate the\n"
405     "  files.\n"
406     "\n"
407     "  The .d file should go in the target output directory. If you have more\n"
408     "  than one source file that the script is being run over, you can use\n"
409     "  the output file expansions described in \"gn help custom\" to name the\n"
410     "  .d file according to the input."
411     "\n"
412     "  The format is that of a Makefile, and all of the paths should be\n"
413     "  relative to the root build directory.\n"
414     "\n"
415     "Example:\n"
416     "  custom(\"myscript_target\") {\n"
417     "    script = \"myscript.py\"\n"
418     "    sources = [ ... ]\n"
419     "\n"
420     "    # Locate the depfile in the output directory named like the\n"
421     "    # inputs but with a \".d\" appended.\n"
422     "    depfile = \"$relative_target_output_dir/{{source_name}}.d\"\n"
423     "\n"
424     "    # Say our script uses \"-o <d file>\" to indicate the depfile.\n"
425     "    args = [ \"{{source}}\", \"-o\", depfile ]\n"
426     "  }\n";
427 
428 const char kDeps[] = "deps";
429 const char kDeps_HelpShort[] =
430     "deps: [label list] Linked dependencies.";
431 const char kDeps_Help[] =
432     "deps: Linked dependencies.\n"
433     "\n"
434     "  A list of target labels.\n"
435     "\n"
436     "  Specifies dependencies of a target. Shared and dynamic libraries will\n"
437     "  be linked into the current target. Other target types that can't be\n"
438     "  linked (like custom scripts and groups) listed in \"deps\" will be\n"
439     "  treated as \"datadeps\". Likewise, if the current target isn't\n"
440     "  linkable, then all deps will be treated as \"datadeps\".\n"
441     "\n"
442     "  See also \"datadeps\".\n";
443 
444 const char kDirectDependentConfigs[] = "direct_dependent_configs";
445 const char kDirectDependentConfigs_HelpShort[] =
446     "direct_dependent_configs: [label list] Configs to be forced on "
447     "dependents.";
448 const char kDirectDependentConfigs_Help[] =
449     "direct_dependent_configs: Configs to be forced on dependents.\n"
450     "\n"
451     "  A list of config labels.\n"
452     "\n"
453     "  Targets directly referencing this one will have the configs listed in\n"
454     "  this variable added to them. These configs will also apply to the\n"
455     "  current target.\n"
456     "\n"
457     "  This addition happens in a second phase once a target and all of its\n"
458     "  dependencies have been resolved. Therefore, a target will not see\n"
459     "  these force-added configs in their \"configs\" variable while the\n"
460     "  script is running, and then can not be removed. As a result, this\n"
461     "  capability should generally only be used to add defines and include\n"
462     "  directories necessary to compile a target's headers.\n"
463     "\n"
464     "  See also \"all_dependent_configs\".\n";
465 
466 const char kExternal[] = "external";
467 const char kExternal_HelpShort[] =
468     "external: [boolean] Declares a target as externally generated.";
469 const char kExternal_Help[] =
470     "external: Declares a target as externally generated.\n"
471     "\n"
472     "  External targets are treated like normal targets as far as dependent\n"
473     "  targets are concerned, but do not actually have their .ninja file\n"
474     "  written to disk. This allows them to be generated by an external\n"
475     "  program (e.g. GYP).\n"
476     "\n"
477     "  See also \"gn help gyp\".\n"
478     "\n"
479     "Example:\n"
480     "  static_library(\"foo\") {\n"
481     "    external = true\n"
482     "  }\n";
483 
484 const char kForwardDependentConfigsFrom[] = "forward_dependent_configs_from";
485 const char kForwardDependentConfigsFrom_HelpShort[] =
486     "forward_dependent_configs_from: [label list] Forward dependent's configs.";
487 const char kForwardDependentConfigsFrom_Help[] =
488     "forward_dependent_configs_from\n"
489     "\n"
490     "  A list of target labels.\n"
491     "\n"
492     "  Exposes the direct_dependent_configs from a dependent target as\n"
493     "  direct_dependent_configs of the current one. Each label in this list\n"
494     "  must also be in the deps.\n"
495     "\n"
496     "  Sometimes you depend on a child library that exports some necessary\n"
497     "  configuration via direct_dependent_configs. If your target in turn\n"
498     "  exposes the child library's headers in its public headers, it might\n"
499     "  mean that targets that depend on you won't work: they'll be seeing the\n"
500     "  child library's code but not the necessary configuration. This list\n"
501     "  specifies which of your deps' direct dependent configs to expose as\n"
502     "  your own.\n"
503     "\n"
504     "Examples:\n"
505     "\n"
506     "  If we use a given library \"a\" from our public headers:\n"
507     "\n"
508     "    deps = [ \":a\", \":b\", ... ]\n"
509     "    forward_dependent_configs_from = [ \":a\" ]\n"
510     "\n"
511     "  This example makes a \"transparent\" target that forwards a dependency\n"
512     "  to another:\n"
513     "\n"
514     "    group(\"frob\") {\n"
515     "      if (use_system_frob) {\n"
516     "        deps = \":system_frob\"\n"
517     "      } else {\n"
518     "        deps = \"//third_party/fallback_frob\"\n"
519     "      }\n"
520     "      forward_dependent_configs_from = deps\n"
521     "    }\n";
522 
523 const char kGypFile[] = "gyp_file";
524 const char kGypFile_HelpShort[] =
525     "gyp_file: [file name] Name of GYP file to write to in GYP mode.";
526 const char kGypFile_Help[] =
527     "gyp_file: Name of GYP file to write to in GYP mode.\n"
528     "\n"
529     "  See \"gn help gyp\" for an overview of how this works.\n"
530     "\n"
531     "  Tip: If all targets in a given BUILD.gn file should go in the same\n"
532     "  GYP file, just put gyp_file = \"foo\" at the top of the file and\n"
533     "  the variable will be in scope for all targets.\n";
534 
535 const char kGypHeader[] = "gyp_header";
536 const char kGypHeader_HelpShort[] =
537     "gyp_header: [string] Extra stuff to prepend to GYP files.";
538 const char kGypHeader_Help[] =
539     "gyp_header: Extra stuff to prepend to GYP files.\n"
540     "\n"
541     "  A Python dictionary string. This will be inserted after the initial\n"
542     "  \"{\" in the GYP file. It is expected this is used to define the\n"
543     "  make_global_settings.\n"
544     "\n"
545     "  This string should end in a comma to keep the python dictionary syntax\n"
546     "  valid when everything is concatenated.\n";
547 
548 const char kHardDep[] = "hard_dep";
549 const char kHardDep_HelpShort[] =
550     "hard_dep: [boolean] Indicates a target should be built before dependees.";
551 const char kHardDep_Help[] =
552     "hard_dep: Indicates a target should be built before dependees.\n"
553     "\n"
554     "  Ninja's default is to assume that targets can be compiled\n"
555     "  independently. This breaks down for generated files that are included\n"
556     "  in other targets because Ninja doesn't know to run the generator\n"
557     "  before compiling the source file.\n"
558     "\n"
559     "  Setting \"hard_dep\" to true on a target means that no sources in\n"
560     "  targets depending directly on this one will be compiled until this\n"
561     "  target is complete. It will introduce a Ninja implicit dependency\n"
562     "  from those sources to this target. This flag is not transitive so\n"
563     "  it will only affect direct dependents, which will cause problems if\n"
564     "  a direct dependent uses this generated file in a public header that a\n"
565     "  third target consumes. Try not to do this.\n"
566     "\n"
567     "  See also \"gn help source_prereqs\" which allows you to specify the\n"
568     "  exact generated file dependency on the target consuming it.\n"
569     "\n"
570     "Example:\n"
571     "  executable(\"foo\") {\n"
572     "    # myresource will be run before any of the sources in this target\n"
573     "    # are compiled.\n"
574     "    deps = [ \":myresource\" ]\n"
575     "    ...\n"
576     "  }\n"
577     "\n"
578     "  custom(\"myresource\") {\n"
579     "    hard_dep = true\n"
580     "    script = \"my_generator.py\"\n"
581     "    outputs = \"$target_gen_dir/myresource.h\"\n"
582     "  }\n";
583 
584 const char kIncludeDirs[] = "include_dirs";
585 const char kIncludeDirs_HelpShort[] =
586     "include_dirs: [directory list] Additional include directories.";
587 const char kIncludeDirs_Help[] =
588     "include_dirs: Additional include directories.\n"
589     "\n"
590     "  A list of source directories.\n"
591     "\n"
592     "  The directories in this list will be added to the include path for\n"
593     "  the files in the affected target.\n"
594     "\n"
595     "Example:\n"
596     "  include_dirs = [ \"src/include\", \"//third_party/foo\" ]\n";
597 
598 const char kLdflags[] = "ldflags";
599 const char kLdflags_HelpShort[] =
600     "ldflags: [string list] Flags passed to the linker.";
601 const char kLdflags_Help[] =
602     "ldflags: Flags passed to the linker.\n"
603     "\n"
604     "  A list of strings.\n"
605     "\n"
606     "  These flags are passed on the command-line to the linker and generally\n"
607     "  specify various linking options. Most targets will not need these and\n"
608     "  will use \"libs\" and \"lib_dirs\" instead.\n"
609     COMMON_FLAGS_HELP;
610 
611 #define COMMON_LIB_INHERITANCE_HELP \
612     "\n" \
613     "  libs and lib_dirs work differently than other flags in two respects.\n" \
614     "  First, then are inherited across static library boundaries until a\n" \
615     "  shared library or executable target is reached. Second, they are\n" \
616     "  uniquified so each one is only passed once (the first instance of it\n" \
617     "  will be the one used).\n" \
618     "\n" \
619     "  The order that libs/lib_dirs apply is:\n" \
620     "    1. Ones set on the target itself.\n" \
621     "    2. Ones from the configs applying to the target.\n" \
622     "    3. Ones from deps of the target, in order (recursively following\n" \
623     "       these rules).\n"
624 
625 const char kLibDirs[] = "lib_dirs";
626 const char kLibDirs_HelpShort[] =
627     "lib_dirs: [directory list] Additional library directories.";
628 const char kLibDirs_Help[] =
629     "lib_dirs: Additional library directories.\n"
630     "\n"
631     "  A list of directories.\n"
632     "\n"
633     "  Specifies additional directories passed to the linker for searching\n"
634     "  for the required libraries. If an item is not an absolute path, it\n"
635     "  will be treated as being relative to the current build file.\n"
636     COMMON_LIB_INHERITANCE_HELP
637     "\n"
638     "Example:\n"
639     "  lib_dirs = [ \"/usr/lib/foo\", \"lib/doom_melon\" ]\n";
640 
641 const char kLibs[] = "libs";
642 const char kLibs_HelpShort[] =
643     "libs: [string list] Additional libraries to link.";
644 const char kLibs_Help[] =
645     "libs: Additional libraries to link.\n"
646     "\n"
647     "  A list of strings.\n"
648     "\n"
649     "  These files will be passed to the linker, which will generally search\n"
650     "  the library include path. Unlike a normal list of files, they will be\n"
651     "  passed to the linker unmodified rather than being treated as file\n"
652     "  names relative to the current build file. Generally you would set\n"
653     "  the \"lib_dirs\" so your library is found. If you need to specify\n"
654     "  a path, you can use \"rebase_path\" to convert a path to be relative\n"
655     "  to the build directory.\n"
656     "\n"
657     "  When constructing the linker command, the \"lib_prefix\" attribute of\n"
658     "  the linker tool in the current toolchain will be prepended to each\n"
659     "  library. So your BUILD file should not specify the switch prefix\n"
660     "  (like \"-l\"). On Mac, libraries ending in \".framework\" will be\n"
661     "  special-cased: the switch \"-framework\" will be prepended instead of\n"
662     "  the lib_prefix, and the \".framework\" suffix will be trimmed.\n"
663     COMMON_LIB_INHERITANCE_HELP
664     "\n"
665     "Examples:\n"
666     "  On Windows:\n"
667     "    libs = [ \"ctl3d.lib\" ]\n"
668     "  On Linux:\n"
669     "    libs = [ \"ld\" ]\n";
670 
671 const char kOutputName[] = "output_name";
672 const char kOutputName_HelpShort[] =
673     "output_name: [string] Name for the output file other than the default.";
674 const char kOutputName_Help[] =
675     "output_name: Define a name for the output file other than the default.\n"
676     "\n"
677     "  Normally the output name of a target will be based on the target name,\n"
678     "  so the target \"//foo/bar:bar_unittests\" will generate an output\n"
679     "  file such as \"bar_unittests.exe\" (using Windows as an example).\n"
680     "\n"
681     "  Sometimes you will want an alternate name to avoid collisions or\n"
682     "  if the internal name isn't appropriate for public distribution.\n"
683     "\n"
684     "  The output name should have no extension or prefixes, these will be\n"
685     "  added using the default system rules. For example, on Linux an output\n"
686     "  name of \"foo\" will produce a shared library \"libfoo.so\".\n"
687     "\n"
688     "  This variable is valid for all binary output target types.\n"
689     "\n"
690     "Example:\n"
691     "  static_library(\"doom_melon\") {\n"
692     "    output_name = \"fluffy_bunny\"\n"
693     "  }\n";
694 
695 const char kOutputs[] = "outputs";
696 const char kOutputs_HelpShort[] =
697     "outputs: [file list] Output files for custom script and copy targets.";
698 const char kOutputs_Help[] =
699     "outputs: Output files for custom script and copy targets.\n"
700     "\n"
701     "  Outputs is valid for \"copy\" and \"custom\" target types and\n"
702     "  indicates the resulting files. The values may contain source\n"
703     "  expansions to generate the output names from the sources (see\n"
704     "  \"gn help source_expansion\").\n"
705     "\n"
706     "  For copy targets, the outputs is the destination for the copied\n"
707     "  file(s). For custom script targets, the outputs should be the list of\n"
708     "  files generated by the script.\n";
709 
710 const char kScript[] = "script";
711 const char kScript_HelpShort[] =
712     "script: [file name] Script file for custom script targets.";
713 const char kScript_Help[] =
714     "script: Script file for custom script targets.\n"
715     "\n"
716     "  An absolute or buildfile-relative file name of a Python script to run\n"
717     "  for a custom script target (see \"gn help custom\").\n";
718 
719 const char kSourcePrereqs[] = "source_prereqs";
720 const char kSourcePrereqs_HelpShort[] =
721     "source_prereqs: [file list] Additional compile-time dependencies.";
722 const char kSourcePrereqs_Help[] =
723     "source_prereqs: Additional compile-time dependencies.\n"
724     "\n"
725     "  Inputs are compile-time dependencies of the current target. This means\n"
726     "  that all source prerequisites must be available before compiling any\n"
727     "  of the sources.\n"
728     "\n"
729     "  If one of your sources #includes a generated file, that file must be\n"
730     "  available before that source file is compiled. For subsequent builds,\n"
731     "  the \".d\" files will list the include dependencies of each source\n"
732     "  and Ninja can know about that dependency to make sure it's generated\n"
733     "  before compiling your source file. However, for the first run it's\n"
734     "  not possible for Ninja to know about this dependency.\n"
735     "\n"
736     "  Source prerequisites solves this problem by declaring such\n"
737     "  dependencies. It will introduce a Ninja \"implicit\" dependency for\n"
738     "  each source file in the target on the listed files.\n"
739     "\n"
740     "  For binary targets, the files in the \"source_prereqs\" should all be\n"
741     "  listed in the \"outputs\" section of another target. There is no\n"
742     "  reason to declare static source files as source prerequisites since\n"
743     "  the normal include file dependency management will handle them more\n"
744     "  efficiently anwyay.\n"
745     "\n"
746     "  For custom script targets that don't generate \".d\" files, the\n"
747     "  \"source_prereqs\" section is how you can list known compile-time\n"
748     "  dependencies your script may have.\n"
749     "\n"
750     "  See also \"gn help data\" and \"gn help datadeps\" (which declare\n"
751     "  run-time rather than compile-time dependencies), and\n"
752     "  \"gn help hard_dep\" which allows you to declare the source dependency\n"
753     "  on the target generating a file rather than the target consuming it.\n"
754     "\n"
755     "Examples:\n"
756     "  executable(\"foo\") {\n"
757     "    sources = [ \"foo.cc\" ]\n"
758     "    source_prereqs = [ \"$root_gen_dir/something/generated_data.h\" ]\n"
759     "  }\n"
760     "\n"
761     "  custom(\"myscript\") {\n"
762     "    script = \"domything.py\"\n"
763     "    source_prereqs = [ \"input.data\" ]\n"
764     "  }\n";
765 
766 const char kSources[] = "sources";
767 const char kSources_HelpShort[] =
768     "sources: [file list] Source files for a target.";
769 const char kSources_Help[] =
770     "sources: Source files for a target\n"
771     "\n"
772     "  A list of files relative to the current buildfile.\n";
773 
774 // -----------------------------------------------------------------------------
775 
VariableInfo()776 VariableInfo::VariableInfo()
777     : help_short(NULL),
778       help(NULL) {
779 }
780 
VariableInfo(const char * in_help_short,const char * in_help)781 VariableInfo::VariableInfo(const char* in_help_short, const char* in_help)
782     : help_short(in_help_short),
783       help(in_help) {
784 }
785 
786 #define INSERT_VARIABLE(var) \
787     info_map[k##var] = VariableInfo(k##var##_HelpShort, k##var##_Help);
788 
GetBuiltinVariables()789 const VariableInfoMap& GetBuiltinVariables() {
790   static VariableInfoMap info_map;
791   if (info_map.empty()) {
792     INSERT_VARIABLE(BuildCpuArch)
793     INSERT_VARIABLE(BuildOs)
794     INSERT_VARIABLE(CpuArch)
795     INSERT_VARIABLE(ComponentMode)
796     INSERT_VARIABLE(CurrentToolchain)
797     INSERT_VARIABLE(DefaultToolchain)
798     INSERT_VARIABLE(Os)
799     INSERT_VARIABLE(PythonPath)
800     INSERT_VARIABLE(RootBuildDir)
801     INSERT_VARIABLE(RootGenDir)
802     INSERT_VARIABLE(RootOutDir)
803     INSERT_VARIABLE(TargetGenDir)
804     INSERT_VARIABLE(TargetOutDir)
805   }
806   return info_map;
807 }
808 
GetTargetVariables()809 const VariableInfoMap& GetTargetVariables() {
810   static VariableInfoMap info_map;
811   if (info_map.empty()) {
812     INSERT_VARIABLE(AllDependentConfigs)
813     INSERT_VARIABLE(Args)
814     INSERT_VARIABLE(Cflags)
815     INSERT_VARIABLE(CflagsC)
816     INSERT_VARIABLE(CflagsCC)
817     INSERT_VARIABLE(CflagsObjC)
818     INSERT_VARIABLE(CflagsObjCC)
819     INSERT_VARIABLE(Configs)
820     INSERT_VARIABLE(Data)
821     INSERT_VARIABLE(Datadeps)
822     INSERT_VARIABLE(Depfile)
823     INSERT_VARIABLE(Deps)
824     INSERT_VARIABLE(DirectDependentConfigs)
825     INSERT_VARIABLE(External)
826     INSERT_VARIABLE(ForwardDependentConfigsFrom)
827     INSERT_VARIABLE(GypFile)
828     INSERT_VARIABLE(HardDep)
829     INSERT_VARIABLE(IncludeDirs)
830     INSERT_VARIABLE(Ldflags)
831     INSERT_VARIABLE(Libs)
832     INSERT_VARIABLE(LibDirs)
833     INSERT_VARIABLE(OutputName)
834     INSERT_VARIABLE(Outputs)
835     INSERT_VARIABLE(Script)
836     INSERT_VARIABLE(SourcePrereqs)
837     INSERT_VARIABLE(Sources)
838   }
839   return info_map;
840 }
841 
842 #undef INSERT_VARIABLE
843 
844 }  // namespace variables
845