Support clang_cl builds on Windows

Change-Id: I1f3e8fc378cfceda92ff17fcc7669c0f5d97c3f7
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

2 files changed, 18 insertions, 5 deletions

diff --git a/src/core/config/linux.pri b/src/core/config/linux.pri
index 3eb436910..95b7a4bda 100644
--- a/src/core/config/linux.pri
+++ b/src/core/config/linux.pri
@@ -36,8 +36,7 @@ clang {
     gn_args += \
         is_clang=true \
         clang_use_chrome_plugins=false \
-        clang_base_path=\"$${clang_prefix}\" \
-        use_lld=false
+        clang_base_path=\"$${clang_prefix}\"
 
     linux-clang-libc++: gn_args += use_libcxx=true
 } else {
diff --git a/src/core/config/windows.pri b/src/core/config/windows.pri
index 9eb15830d..b934ea475 100644
--- a/src/core/config/windows.pri
+++ b/src/core/config/windows.pri
@@ -1,7 +1,6 @@
 include(common.pri)
 
 gn_args += \
-    is_clang=false \
     use_sysroot=false \
     enable_session_service=false \
     ninja_use_custom_environment_files=false \
@@ -9,6 +8,22 @@ gn_args += \
     win_linker_timing=true \
     com_init_check_hook_disabled=true
 
+use_lld_linker: gn_args += use_lld=true
+else: gn_args += use_lld=false
+
+clang_cl {
+    clang_full_path = $$system_path($$which($${QMAKE_CXX}))
+    # Remove the "\bin\clang-cl.exe" part:
+    clang_dir = $$dirname(clang_full_path)
+    clang_prefix = $$join(clang_dir,,,"\..")
+    gn_args += \
+        is_clang=true \
+        clang_use_chrome_plugins=false \
+        clang_base_path=$$system_quote($$system_path($$clean_path($$clang_prefix)))
+} else {
+    gn_args += is_clang=false
+}
+
 isDeveloperBuild() {
     gn_args += \
         is_win_fastlink=true
@@ -69,7 +84,6 @@ msvc {
 
     GN_TARGET_CPU = $$gnArch($$QT_ARCH)
     gn_args += target_cpu=\"$$GN_TARGET_CPU\"
-
 } else {
-    error("Qt WebEngine for Windows can only be built with the Microsoft Visual Studio C++ compiler")
+    error("Qt WebEngine for Windows can only be built with a Microsoft Visual Studio C++ compatible compiler")
 }