From 10ca2026a96b14ead483aa895ce5c33d33aebb94 Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Sat, 12 Nov 2016 23:36:41 +0000
Subject: [PATCH] refs #802 Enable build with Clang on Windows.

---
 mkspecs/features/common_pre.prf | 31 +++++++++++++++++++++++++------
 mkspecs/features/libraries.pri  | 18 +++++++++---------
 mkspecs/features/warnings.pri   |  1 +
 3 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/mkspecs/features/common_pre.prf b/mkspecs/features/common_pre.prf
index 4dd456c6a..85eb918f0 100644
--- a/mkspecs/features/common_pre.prf
+++ b/mkspecs/features/common_pre.prf
@@ -68,7 +68,7 @@ contains(BLACK_CONFIG, ProfileRelease) {
 # Workaround C1128 error
 ################################
 
-msvc: QMAKE_CXXFLAGS *= /bigobj
+msvc:!llvm: QMAKE_CXXFLAGS *= /bigobj
 
 ################################
 # No gigantic MinGW obj files
@@ -123,18 +123,21 @@ isEmpty(EXTERNALSROOT) {
 # Externals
 ################################
 
+clang_cl: EXTERNALS_SPEC = win32-msvc2015
+else: EXTERNALS_SPEC = $$basename(QMAKESPEC)
+
 INCLUDEPATH *= $$EXTERNALSROOT/common/include
-INCLUDEPATH *= $$EXTERNALSROOT/$$basename(QMAKESPEC)/include
+INCLUDEPATH *= $$EXTERNALSROOT/$$EXTERNALS_SPEC/include
 INCLUDEPATH *= $$EXTERNALSROOT/common/include/crashpad
 INCLUDEPATH *= $$EXTERNALSROOT/common/include/mini_chromium
 
 equals(WORD_SIZE,64) {
-    EXTERNALS_BIN_DIR = $$EXTERNALSROOT/$$basename(QMAKESPEC)/bin64
-    EXTERNALS_LIB_DIR = $$EXTERNALSROOT/$$basename(QMAKESPEC)/lib64
+    EXTERNALS_BIN_DIR = $$EXTERNALSROOT/$$EXTERNALS_SPEC/bin64
+    EXTERNALS_LIB_DIR = $$EXTERNALSROOT/$$EXTERNALS_SPEC/lib64
 }
 equals(WORD_SIZE,32) {
-    EXTERNALS_BIN_DIR = $$EXTERNALSROOT/$$basename(QMAKESPEC)/bin32
-    EXTERNALS_LIB_DIR = $$EXTERNALSROOT/$$basename(QMAKESPEC)/lib32
+    EXTERNALS_BIN_DIR = $$EXTERNALSROOT/$$EXTERNALS_SPEC/bin32
+    EXTERNALS_LIB_DIR = $$EXTERNALSROOT/$$EXTERNALS_SPEC/lib32
 }
 
 LIBS *= -L$$EXTERNALS_LIB_DIR
@@ -176,3 +179,19 @@ isEmpty(PREFIX) {
 ################################
 
 win32: CONFIG(debug, debug|release): DLL_DEBUG_SUFFIX = d
+
+################################
+# Experimental support for Clang on Windows
+################################
+
+clang_cl {
+    QMAKE_CXXFLAGS ~= s/-fms-compatibility-version=.+/
+    QMAKE_CXXFLAGS += -fms-compatibility-version=19.00.24210
+
+    # QtCreator ships with a version of clang-cl,
+    # but we want to use the one in PATH instead.
+    system($$(SYSTEMROOT)\system32\where /q clang-cl) {
+        QMAKE_CC = $$system($$(SYSTEMROOT)\system32\where clang-cl)
+        QMAKE_CXX = $$QMAKE_CC
+    }
+}
diff --git a/mkspecs/features/libraries.pri b/mkspecs/features/libraries.pri
index ca172e490..3eadb814b 100644
--- a/mkspecs/features/libraries.pri
+++ b/mkspecs/features/libraries.pri
@@ -8,10 +8,10 @@ unix:!macx {
 
 blackgui {
     contains(BLACK_CONFIG, Static) {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackgui.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackgui.lib
         else:           PRE_TARGETDEPS += $$DestRoot/lib/libblackgui.a
     } else {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackgui.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackgui.lib
         win32-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackgui.a
         linux-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackgui.so
         macx-clang:     PRE_TARGETDEPS += $$DestRoot/lib/libblackgui.dylib
@@ -22,10 +22,10 @@ blackgui {
 
 blackcore {
     contains(BLACK_CONFIG, Static) {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackcore.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackcore.lib
         else:           PRE_TARGETDEPS += $$DestRoot/lib/libblackcore.a
     } else {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackcore.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackcore.lib
         win32-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackcore.a
         linux-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackcore.so
         macx-clang:     PRE_TARGETDEPS += $$DestRoot/lib/libblackcore.dylib
@@ -47,10 +47,10 @@ blacksound {
 
 blackinput {
     contains(BLACK_CONFIG, Static) {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackinput.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackinput.lib
         else:           PRE_TARGETDEPS += $$DestRoot/lib/libblackinput.a
     } else {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackinput.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackinput.lib
         win32-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackinput.a
         linux-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackinput.so
         macx-clang:     PRE_TARGETDEPS += $$DestRoot/lib/libblackinput.dylib
@@ -69,10 +69,10 @@ blackinput {
 
 blackmisc {
     contains(BLACK_CONFIG, Static) {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackmisc.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackmisc.lib
         else:           PRE_TARGETDEPS += $$DestRoot/lib/libblackmisc.a
     } else {
-        win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackmisc.lib
+        win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackmisc.lib
         win32-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackmisc.a
         linux-g++*:     PRE_TARGETDEPS += $$DestRoot/lib/libblackmisc.so
         macx-clang:     PRE_TARGETDEPS += $$DestRoot/lib/libblackmisc.dylib
@@ -85,7 +85,7 @@ blackmisc {
 }
 
 blackconfig {
-    win32-msvc*:    PRE_TARGETDEPS += $$DestRoot/lib/blackconfig.lib
+    win32:msvc:     PRE_TARGETDEPS += $$DestRoot/lib/blackconfig.lib
     else:           PRE_TARGETDEPS += $$DestRoot/lib/libblackconfig.a
     LIBS *= -lblackconfig
 }
diff --git a/mkspecs/features/warnings.pri b/mkspecs/features/warnings.pri
index b3ec5822d..96f0c6996 100644
--- a/mkspecs/features/warnings.pri
+++ b/mkspecs/features/warnings.pri
@@ -2,6 +2,7 @@ msvc:DEFINES *= _SCL_SECURE_NO_WARNINGS
 
 # swift standard warnings
 msvc:QMAKE_CXXFLAGS_WARN_ON *= /wd4351 /wd4661
+clang_cl:QMAKE_CXXFLAGS_WARN_ON *= -Wall -Wextra
 
 # elevated warnings
 contains(BLACK_CONFIG, AllowNoisyWarnings) {