[GN]: Support for loadable modules

tools/gn/docs/reference.md

Index: tools/gn/docs/reference.md
diff --git a/tools/gn/docs/reference.md b/tools/gn/docs/reference.md
index 657796abc8fb4e71a7561473fc03874a46ec3e5e..f5ff3b4cbc6eebd68189b4344d853e66a21a4d5c 100644
--- a/tools/gn/docs/reference.md
+++ b/tools/gn/docs/reference.md
@@ -378,6 +378,10 @@
       Shows the labels of configs applied to targets that depend on this
       one (either directly or all of them).
 
+  forward_dependent_configs_from

[brettw, 2015/10/14 17:45:56]

I think this is a merge mistake and that Thiago removed this stuff. Maybe
regenerate the file after you merge (same for the other forward* stuff below).

[Bons, 2015/10/14 18:03:42]

Done.

+      Shows the labels of dependencies for which dependent configs will
+      be pushed to targets depending on the current one.
+
   script
   args
   depfile
@@ -1025,14 +1029,15 @@
 ### **Variables valid in a config definition**:
 ```
   Flags: cflags, cflags_c, cflags_cc, cflags_objc, cflags_objcc,
-         defines, include_dirs, ldflags, lib_dirs, libs,
+         asmflags, defines, include_dirs, ldflags, lib_dirs, libs,
          precompiled_header, precompiled_source
 
 ```
 
 ### **Variables on a target used to apply configs**:
 ```
-  all_dependent_configs, configs, public_configs
+  all_dependent_configs, configs, public_configs,
+  forward_dependent_configs_from
 
 ```
 
@@ -1223,9 +1228,9 @@
 
 ```
   Flags: cflags, cflags_c, cflags_cc, cflags_objc, cflags_objcc,
-         defines, include_dirs, ldflags, lib_dirs, libs,
+         asmflags, defines, include_dirs, ldflags, lib_dirs, libs,
          precompiled_header, precompiled_source
-  Deps: data_deps, deps, public_deps
+  Deps: data_deps, deps, forward_dependent_configs_from, public_deps
   Dependent configs: all_dependent_configs, public_configs
   General: check_includes, configs, data, inputs, output_name,
            output_extension, public, sources, testonly, visibility
@@ -1582,14 +1587,16 @@
   specify configs that apply to their dependents.
 
   Depending on a group is exactly like depending directly on that
-  group's deps.
+  group's deps. Direct dependent configs will get automatically
+  forwarded through the group so you shouldn't need to use
+  "forward_dependent_configs_from.
 
 ```
 
 ### **Variables**
 
 ```
-  Deps: data_deps, deps, public_deps
+  Deps: data_deps, deps, forward_dependent_configs_from, public_deps
   Dependent configs: all_dependent_configs, public_configs
 
 ```
@@ -1996,9 +2003,9 @@
 
 ```
   Flags: cflags, cflags_c, cflags_cc, cflags_objc, cflags_objcc,
-         defines, include_dirs, ldflags, lib_dirs, libs,
+         asmflags, defines, include_dirs, ldflags, lib_dirs, libs,
          precompiled_header, precompiled_source
-  Deps: data_deps, deps, public_deps
+  Deps: data_deps, deps, forward_dependent_configs_from, public_deps
   Dependent configs: all_dependent_configs, public_configs
   General: check_includes, configs, data, inputs, output_name,
            output_extension, public, sources, testonly, visibility
@@ -2037,9 +2044,9 @@
 
 ```
   Flags: cflags, cflags_c, cflags_cc, cflags_objc, cflags_objcc,
-         defines, include_dirs, ldflags, lib_dirs, libs,
+         asmflags, defines, include_dirs, ldflags, lib_dirs, libs,
          precompiled_header, precompiled_source
-  Deps: data_deps, deps, public_deps
+  Deps: data_deps, deps, forward_dependent_configs_from, public_deps
   Dependent configs: all_dependent_configs, public_configs
   General: check_includes, configs, data, inputs, output_name,
            output_extension, public, sources, testonly, visibility
@@ -2061,9 +2068,9 @@
 
 ```
   Flags: cflags, cflags_c, cflags_cc, cflags_objc, cflags_objcc,
-         defines, include_dirs, ldflags, lib_dirs, libs,
+         asmflags, defines, include_dirs, ldflags, lib_dirs, libs,
          precompiled_header, precompiled_source
-  Deps: data_deps, deps, public_deps
+  Deps: data_deps, deps, forward_dependent_configs_from, public_deps
   Dependent configs: all_dependent_configs, public_configs
   General: check_includes, configs, data, inputs, output_name,
            output_extension, public, sources, testonly, visibility
@@ -2511,6 +2518,7 @@
   along with a set of compiler-specific flags. The following expansions
   are available:
 
+    {{asmflags}}
     {{cflags}}
     {{cflags_c}}
     {{cflags_cc}}
@@ -3217,8 +3225,11 @@
   and Objective C++ compilers.
 
   To target one of these variants individually, use "cflags_c",
-  "cflags_cc", "cflags_objc", and "cflags_objcc", respectively.
-  These variant-specific versions will be appended to the "cflags".
+  "cflags_cc", "cflags_objc", and "cflags_objcc",
+  respectively.
+
+  These variant-specific versions of cflags* will be appended to the
+  "cflags".
 
 ```
 
@@ -3250,8 +3261,11 @@
   and Objective C++ compilers.
 
   To target one of these variants individually, use "cflags_c",
-  "cflags_cc", "cflags_objc", and "cflags_objcc", respectively.
-  These variant-specific versions will be appended to the "cflags".
+  "cflags_cc", "cflags_objc", and "cflags_objcc",
+  respectively.
+
+  These variant-specific versions of cflags* will be appended to the
+  "cflags".
 
 ```
 
@@ -3283,8 +3297,11 @@
   and Objective C++ compilers.
 
   To target one of these variants individually, use "cflags_c",
-  "cflags_cc", "cflags_objc", and "cflags_objcc", respectively.
-  These variant-specific versions will be appended to the "cflags".
+  "cflags_cc", "cflags_objc", and "cflags_objcc",
+  respectively.
+
+  These variant-specific versions of cflags* will be appended to the
+  "cflags".
 
 ```
 
@@ -3316,8 +3333,11 @@
   and Objective C++ compilers.
 
   To target one of these variants individually, use "cflags_c",
-  "cflags_cc", "cflags_objc", and "cflags_objcc", respectively.
-  These variant-specific versions will be appended to the "cflags".
+  "cflags_cc", "cflags_objc", and "cflags_objcc",
+  respectively.
+
+  These variant-specific versions of cflags* will be appended to the
+  "cflags".
 
 ```
 
@@ -3349,8 +3369,11 @@
   and Objective C++ compilers.
 
   To target one of these variants individually, use "cflags_c",
-  "cflags_cc", "cflags_objc", and "cflags_objcc", respectively.
-  These variant-specific versions will be appended to the "cflags".
+  "cflags_cc", "cflags_objc", and "cflags_objcc",
+  respectively.
+
+  These variant-specific versions of cflags* will be appended to the
+  "cflags".
 
 ```
 
@@ -3718,6 +3741,56 @@
 
 
 ```
+## **forward_dependent_configs_from**
+
+```
+  A list of target labels.
+
+  DEPRECATED. Use public_deps instead which will have the same effect.
+
+  Exposes the public_configs from a private dependent target as
+  public_configs of the current one. Each label in this list
+  must also be in the deps.
+
+  Generally you should use public_deps instead of this variable to
+  express the concept of exposing a dependency as part of a target's
+  public API. We're considering removing this variable.
+
+```
+
+### **Discussion**
+
+```
+  Sometimes you depend on a child library that exports some necessary
+  configuration via public_configs. If your target in turn exposes the
+  child library's headers in its public headers, it might mean that
+  targets that depend on you won't work: they'll be seeing the child
+  library's code but not the necessary configuration. This list
+  specifies which of your deps' direct dependent configs to expose as
+  your own.
+
+```
+
+### **Examples**
+
+```
+  If we use a given library "a" from our public headers:
+
+    deps = [ ":a", ":b", ... ]
+    forward_dependent_configs_from = [ ":a" ]
+
+  This example makes a "transparent" target that forwards a dependency
+  to another:
+
+    group("frob") {
+      if (use_system_frob) {
+        deps = ":system_frob"
+      } else {
+        deps = "//third_party/fallback_frob"
+      }
+      forward_dependent_configs_from = deps
+    }
+
 
 ```
 ## **include_dirs**: Additional include directories.