Add gn bootstrap to build system

Bootstraps gn wihout rebuild.

Change-Id: I09ee4d6b6f458f16f0d9ac18433823153ab75995
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

2 files changed, 72 insertions, 29 deletions

diff --git a/src/core/core.pro b/src/core/core.pro
index a205d39a0..86fe838cb 100644
--- a/src/core/core.pro
+++ b/src/core/core.pro
@@ -3,39 +3,43 @@ TEMPLATE = subdirs
 # core_headers is a dummy module to syncqt the headers so we can
 # use them by later targets
 core_headers.file = core_headers.pro
-
-# core_gyp_generator.pro is a dummy .pro file that is used by qmake
-# to generate our main .gyp file
-core_gyp_generator.file = core_gyp_generator.pro
-core_gyp_generator.depends = core_headers
-
-# gyp_run.pro calls gyp through gyp_qtwebengine on the qmake step, and ninja on the make step.
-gyp_run.file = gyp_run.pro
-gyp_run.depends = core_gyp_generator
-
 core_api.file = api/core_api.pro
-core_api.depends = gyp_run
 
 # This will take the compile output of ninja, and link+deploy the final binary.
 core_module.file = core_module.pro
 core_module.depends = core_api
 
-SUBDIRS += core_headers \
-           core_gyp_generator
-
-!win32 {
-    # gyp_configure_host.pro and gyp_configure_target.pro are phony pro files that
-    # extract things like compiler and linker from qmake
-    # Do not use them on Windows, where Qt already expects the toolchain to be
-    # selected through environment varibles.
-    gyp_configure_host.file = gyp_configure_host.pro
-    gyp_configure_target.file = gyp_configure_target.pro
-    gyp_configure_target.depends = gyp_configure_host
-
-    gyp_run.depends += gyp_configure_host gyp_configure_target
-    SUBDIRS += gyp_configure_host gyp_configure_target
+contains(WEBENGINE_CONFIG, use_gn) {
+    gn_run.file = gn_run.pro
+    SUBDIRS += gn_run
+} else {
+
+    # core_gyp_generator.pro is a dummy .pro file that is used by qmake
+    # to generate our main .gyp file
+    core_gyp_generator.file = core_gyp_generator.pro
+    core_gyp_generator.depends = core_headers
+
+    # gyp_run.pro calls gyp through gyp_qtwebengine on the qmake step, and ninja on the make step.
+    gyp_run.file = gyp_run.pro
+    gyp_run.depends = core_gyp_generator
+    core_api.depends = gyp_run
+
+    SUBDIRS += gyp_run \
+               core_api \
+               core_module \
+               core_headers \
+               core_gyp_generator
+
+    !win32 {
+        # gyp_configure_host.pro and gyp_configure_target.pro are phony pro files that
+        # extract things like compiler and linker from qmake
+        # Do not use them on Windows, where Qt already expects the toolchain to be
+        # selected through environment varibles.
+        gyp_configure_host.file = gyp_configure_host.pro
+        gyp_configure_target.file = gyp_configure_target.pro
+        gyp_configure_target.depends = gyp_configure_host
+
+        gyp_run.depends += gyp_configure_host gyp_configure_target
+        SUBDIRS += gyp_configure_host gyp_configure_target
+    }
 }
-
-SUBDIRS += gyp_run \
-           core_api \
-           core_module
diff --git a/src/core/gn_run.pro b/src/core/gn_run.pro
new file mode 100644
index 000000000..c379f9510
--- /dev/null
+++ b/src/core/gn_run.pro
@@ -0,0 +1,39 @@
+isQtMinimum(5, 8) {
+    include($$QTWEBENGINE_OUT_ROOT/qtwebengine-config.pri)
+    QT_FOR_CONFIG += webengine-private
+}
+
+TEMPLATE = aux
+
+build_pass|!debug_and_release {
+
+    ninja_binary = ninja
+    runninja.target = run_ninja
+
+    !qtConfig(system-ninja) {
+        ninja_binary = $$shell_quote($$shell_path($$ninjaPath()))
+        buildninja.target = build_ninja
+        buildninja.commands = $$buildNinja()
+        QMAKE_EXTRA_TARGETS += buildninja
+        runninja.depends = buildninja
+    }
+
+    !qtConfig(system-gn) {
+        buildgn.target = build_gn
+        buildgn.commands = $$buildGn()
+        !qtConfig(system-ninja): buildgn.depends = buildninja
+        QMAKE_EXTRA_TARGETS += buildgn
+        runninja.depends = buildgn
+    }
+
+    runninja.commands = $$ninja_binary \$\(NINJAFLAGS\) -C $$shell_quote($$OUT_PWD/$$getConfigDir())
+    QMAKE_EXTRA_TARGETS += runninja
+
+    default_target.depends = buildgn
+
+    QMAKE_EXTRA_TARGETS += default_target
+} else {
+    # Special GNU make target for the meta Makefile that ensures that our debug and release Makefiles won't both run ninja in parallel.
+    notParallel.target = .NOTPARALLEL
+    QMAKE_EXTRA_TARGETS += notParallel
+}