Support cross-builds and alternative compilers with GN

Adds GN versions of the gyp_configure targets, to create custom
toolchains we can use to override compilers used by GN.

Change-Id: Ic3a9cb7e83f845180396faff632f72f9c24f3365
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

3 files changed, 57 insertions, 29 deletions

diff --git a/src/core/config/embedded_linux.pri b/src/core/config/embedded_linux.pri
index 853be7be9..89c9672e9 100644
--- a/src/core/config/embedded_linux.pri
+++ b/src/core/config/embedded_linux.pri
@@ -18,6 +18,11 @@ use?(gn) {
     use?(icecc) {
         gn_args += use_debug_fission=false
     }
+
+    cross_compile:!host_build {
+        TOOLCHAIN_SYSROOT = $$[QT_SYSROOT]
+        !isEmpty(TOOLCHAIN_SYSROOT): gn_args += target_sysroot=\"$${TOOLCHAIN_SYSROOT}\"
+    }
 }
 
 GYP_CONFIG += \
diff --git a/src/core/config/linux.pri b/src/core/config/linux.pri
index 4854fae0d..7b8af34b0 100644
--- a/src/core/config/linux.pri
+++ b/src/core/config/linux.pri
@@ -22,36 +22,59 @@ use?(gn) {
     }
     gcc:!clang: greaterThan(QT_GCC_MAJOR_VERSION, 5): gn_args += no_delete_null_pointer_checks=true
 
-
-    qtConfig(system-zlib): use?(system_minizip): gn_args += use_system_zlib=true use_system_minizip=true
-    qtConfig(system-png): gn_args += use_system_libpng=true
-    qtConfig(system-jpeg): gn_args += use_system_libjpeg=true
-    use?(system_harfbuzz): gn_args += use_system_harfbuzz=true
-    !use?(glib): gn_args += use_glib=false
-    qtConfig(pulseaudio) {
-        gn_args += use_pulseaudio=true
-    } else {
-        gn_args += use_pulseaudio=false
-    }
-    qtConfig(alsa) {
-        gn_args += use_alsa=true
+    host_build {
+        gn_args += custom_toolchain=\"$$QTWEBENGINE_OUT_ROOT/src/toolchain:host\"
+        # Don't bother trying to use system libraries in this case
+        gn_args += use_glib=false
+        gn_args += use_system_libffi=false
     } else {
-        gn_args += use_alsa=false
-    }
-    packagesExist(libffi): gn_args += use_system_libffi=true
-    else: gn_args += use_system_libffi=false
+        gn_args += custom_toolchain=\"$$QTWEBENGINE_OUT_ROOT/src/toolchain:target\"
+        cross_compile {
+            # FIXME: Try enabling snapshot again
+            gn_args += v8_use_snapshot=false
+            gn_args += host_toolchain=\"$$QTWEBENGINE_OUT_ROOT/src/toolchain:host\"
+            gn_args += v8_snapshot_toolchain=\"$$QTWEBENGINE_OUT_ROOT/src/toolchain:v8_snapshot\"
+            GN_HOST_CPU = $$gnArch($$QMAKE_HOST.arch)
+            GN_TARGET_CPU = $$gnArch($$QT_ARCH)
+            gn_args += host_cpu=\"$$GN_HOST_CPU\" target_cpu=\"$$GN_TARGET_CPU\"
+        }
+        !contains(QT_CONFIG, no-pkg-config) {
+            # Strip '>2 /dev/null' from $$pkgConfigExecutable()
+            PKGCONFIG = $$first($$list($$pkgConfigExecutable()))
+            gn_args += pkg_config=\"$$PKGCONFIG\"
+        }
+
+        qtConfig(system-zlib): use?(system_minizip): gn_args += use_system_zlib=true use_system_minizip=true
+        qtConfig(system-png): gn_args += use_system_libpng=true
+        qtConfig(system-jpeg): gn_args += use_system_libjpeg=true
+        use?(system_harfbuzz): gn_args += use_system_harfbuzz=true
+        !use?(glib): gn_args += use_glib=false
+        qtConfig(pulseaudio) {
+            gn_args += use_pulseaudio=true
+        } else {
+            gn_args += use_pulseaudio=false
+        }
+        qtConfig(alsa) {
+            gn_args += use_alsa=true
+        } else {
+            gn_args += use_alsa=false
+        }
+        packagesExist(libffi): gn_args += use_system_libffi=true
+        else: gn_args += use_system_libffi=false
+        !packagesExist(libpci): gn_args += use_libpci=false
 
-    use?(system_libevent): gn_args += use_system_libevent=true
-    use?(system_libwebp):  gn_args += use_system_libwebp=true
-    #use?(system_libsrtp):  gn_args += use_system_libsrtp=true
-    use?(system_libxslt):  gn_args += use_system_libxml=true use_system_libxslt=true
-    #use?(system_jsoncpp):  gn_args += use_system_jsoncpp=true
-    #use?(system_opus):     gn_args += use_system_opus=true
-    use?(system_snappy):   gn_args += use_system_snappy=true
-    #use?(system_vpx):      gn_args += use_system_libvpx=true
-    #use?(system_icu):      gn_args += use_system_icu=true icu_use_data_file=false
-    #use?(system_ffmpeg):   gn_args += use_system_ffmpeg=true
-    #use?(system_protobuf): gn_args += use_system_protobuf=true
+        use?(system_libevent): gn_args += use_system_libevent=true
+        use?(system_libwebp):  gn_args += use_system_libwebp=true
+        #use?(system_libsrtp):  gn_args += use_system_libsrtp=true
+        use?(system_libxslt):  gn_args += use_system_libxml=true use_system_libxslt=true
+        #use?(system_jsoncpp):  gn_args += use_system_jsoncpp=true
+        #use?(system_opus):     gn_args += use_system_opus=true
+        use?(system_snappy):   gn_args += use_system_snappy=true
+        #use?(system_vpx):      gn_args += use_system_libvpx=true
+        #use?(system_icu):      gn_args += use_system_icu=true icu_use_data_file=false
+        #use?(system_ffmpeg):   gn_args += use_system_ffmpeg=true
+        #use?(system_protobuf): gn_args += use_system_protobuf=true
+    }
 }
 
 # linux_use_bundled_gold currently relies on a hardcoded relative path from chromium/src/out/(Release|Debug)
diff --git a/src/core/core_generator.pro b/src/core/core_generator.pro
index 9ea3f7246..c99e10ef8 100644
--- a/src/core/core_generator.pro
+++ b/src/core/core_generator.pro
@@ -40,7 +40,7 @@ RCC_DIR = $$OUT_PWD/$$getConfigDir()/.rcc
 
 # Assume that we want mobile touch and low-end hardware behaviors
 # whenever we are cross compiling.
-cross_compile: DEFINES += QTWEBENGINE_EMBEDDED_SWITCHES
+contains(WEBENGINE_CONFIG, embedded_build): DEFINES += QTWEBENGINE_EMBEDDED_SWITCHES
 
 qtConfig(egl): CONFIG += egl