Add documentation for GN's GYP generation. BUG= R=jamesr@chromium.org Review URL: https://codereview.chromium.org/35933003 Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src Cr-Mirrored-Commit: 0ff08a372f26e388e35d4dc78c6760c6659bab15
diff --git a/tools/gn/command_gyp.cc b/tools/gn/command_gyp.cc index 4d75200..de089d3 100644 --- a/tools/gn/command_gyp.cc +++ b/tools/gn/command_gyp.cc
@@ -270,7 +270,61 @@ const char kGyp[] = "gyp"; const char kGyp_HelpShort[] = "gyp: Make GYP files from GN."; -const char kGyp_Help[] = "Doooooom.\n"; +const char kGyp_Help[] = + "gyp: Make GYP files from GN.\n" + "\n" + " This command will generate GYP files from GN sources. You can then run\n" + " GYP over the result to produce a build. Native GYP targets can depend\n" + " on any GN target except source sets. GN targets can depend on native\n" + " GYP targets, but all/direct dependent settings will NOT be pushed\n" + " across the boundary.\n" + "\n" + " To make this work you first need to manually run GN, then GYP, then\n" + " do the build. Because GN doesn't generate the final .ninja files,\n" + " there will be no rules to regenerate the .ninja files if the inputs\n" + " change, so you will have to manually repeat these steps each time\n" + " something changes:\n" + "\n" + " out/Debug/gn gyp\n" + " python build/gyp_chromiunm\n" + " ninja -C out/Debug foo_target\n" + "\n" + " Two variables are used to control how a target relates to GYP:\n" + "\n" + " - \"external != true\" and \"gyp_file\" is set: This target will be\n" + " written to the named GYP file in the source tree (not restricted to\n" + " an output or generated files directory).\n" + "\n" + " - \"external == true\" and \"gyp_file\" is set: The target will not\n" + " be written to a GYP file. But other targets being written to GYP\n" + " files can depend on it, and they will reference the given GYP file\n" + " name for GYP to use. This allows you to specify how GN->GYP\n" + " dependencies and named, and provides a place to manually set the\n" + " dependent configs from GYP to GN.\n" + "\n" + " - \"gyp_file\" is unset: Like the previous case, but if a GN target is\n" + " being written to a GYP file that depends on this one, the default\n" + " GYP file name will be assumed. The default name will match the name\n" + " of the current directory, so \"//foo/bar:baz\" would be\n" + " \"<(DEPTH)/foo/bar/bar.gyp:baz\".\n" + "\n" + "Example:\n" + " # This target is assumed to be in the GYP build in the file\n" + " # \"foo/foo.gyp\". This declaration tells GN where to find the GYP\n" + " # equivalent, and gives it some direct dependent settings that targets\n" + " # depending on it should receive (since these don't flow from GYP to\n" + " # GN-generated targets).\n" + " shared_library(\"gyp_target\") {\n" + " gyp_file = \"//foo/foo.gyp\"\n" + " external = true\n" + " direct_dependen_configs = [ \":gyp_target_config\" ]\n" + " }\n" + "\n" + " executable(\"my_app\") {\n" + " deps = [ \":gyp_target\" ]\n" + " gyp_file = \"//foo/myapp.gyp\"\n" + " sources = ...\n" + " }\n"; int RunGyp(const std::vector<std::string>& args) { const CommandLine* cmdline = CommandLine::ForCurrentProcess();
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc index 7345b96..ea40ade 100644 --- a/tools/gn/variables.cc +++ b/tools/gn/variables.cc
@@ -492,7 +492,13 @@ const char kGypFile_HelpShort[] = "gyp_file: [file name] Name of GYP file to write to in GYP mode."; const char kGypFile_Help[] = - "gyp_file: Name of GYP file to write to in GYP mode.\n"; + "gyp_file: Name of GYP file to write to in GYP mode.\n" + "\n" + " See \"gn help gyp\" for an overview of how this works.\n" + "\n" + " Tip: If all targets in a given BUILD.gn file should go in the same\n" + " GYP file, just put gyp_file = \"foo\" at the top of the file and\n" + " the variable will be in scope for all targets.\n"; const char kHardDep[] = "hard_dep"; const char kHardDep_HelpShort[] =