GN: Add notion of 'complete' static libraries, akin to GYP.

tools/gn/variables.cc

Index: tools/gn/variables.cc
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index af75aef874eb97891a8ca3e5c10ae88bdc4d7f1e..6e034e3c1d95668efed3c71e5438b43c326c5930 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -368,6 +368,24 @@ const char kCheckIncludes_Help[] =
     "    ...\n"
     "  }\n";
 
+const char kCompleteStaticLib[] = "complete_static_lib";
+const char kCompleteStaticLib_HelpShort[] =
+    "complete_static_lib: [boolean] Actually link this static library target";
+const char kCompleteStaticLib_Help[] =
+    "complete_static_lib: [boolean] Actually link this static library target\n"
+    "\n"
+    "  Static libraries are normally treated roughly like source_sets, in\n"

[brettw, 2014/09/12 20:53:33]

I don't like defining static libraries in terms of source sets, since nobody
knows what a source set is. Maybe something like (feel free to clarify):


Links all dependencies into a static library.

A static library normally doesn't include code from dependencies, but instead
forward the static libraries and source sets in its deps up the dependency chain
until a linkable target (an executable or shared library) is reached. The final
linkable target only links each static library once, even if it appears more
than once in its dependency graph.

In some cases the static library might be the final desired output. For example,
you may be producing a static library for distribution to third parties. In this
case, the static library should include code from all dependencies in one
complete package.

[Chris Masone, 2014/09/12 22:56:37]

Done.

+    "  that they are mostly just a way to group objects that are then linked\n"
+    "  into any upstream linkable targets (generally, executables and shared\n"
+    "  libraries). This is to avoid duplication in cases where multiple\n"
+    "  static libraries depend on the same target. This flag allows a given\n"
+    "  static library target to be explicitly made linkable.\n"
+    "\n"
+    "Example:\n"

[brettw, 2014/09/12 20:53:34]

I've been doing no colon and a blank line after these headings.

[Chris Masone, 2014/09/12 22:56:37]

Done.

+    "  static_library(\"foo\") {\n"
+    "    complete_static_lib = true  # Force foo to.\n"

[brettw, 2014/09/12 20:53:33]

Delete comment. And maybe add a line with deps that would get linked.

[Chris Masone, 2014/09/12 22:56:37]

Done.

+    "  }\n";
+
 const char kConfigs[] = "configs";
 const char kConfigs_HelpShort[] =
     "configs: [label list] Configs applying to this target.";
@@ -918,6 +936,7 @@ const VariableInfoMap& GetTargetVariables() {
     INSERT_VARIABLE(CflagsObjC)
     INSERT_VARIABLE(CflagsObjCC)
     INSERT_VARIABLE(CheckIncludes)
+    INSERT_VARIABLE(CompleteStaticLib)
     INSERT_VARIABLE(Configs)
     INSERT_VARIABLE(Data)
     INSERT_VARIABLE(Datadeps)