From d993ebd4ca0fc1044745dd1874bab082090f9801 Mon Sep 17 00:00:00 2001
From: Thomas Bernard <tbernard@go-engineering.de>
Date: Tue, 28 Jul 2020 22:12:13 +0200
Subject: clang-cl: Add '--' before source file

On Linux and macOS, absolute paths start with `/` which may be
interpreted by clang-cl as an option.  To avoid this, we separate the
source file path from preceding options with `--` to tell `clang-cl` it
is not an option.
---
 Modules/Platform/Windows-Clang.cmake | 2 +-
 Modules/Platform/Windows-MSVC.cmake  | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Modules/Platform/Windows-Clang.cmake b/Modules/Platform/Windows-Clang.cmake
index 7cd06a2..05dff9d 100644
--- a/Modules/Platform/Windows-Clang.cmake
+++ b/Modules/Platform/Windows-Clang.cmake
@@ -142,7 +142,7 @@ if("x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC"
       endif()
       if(DEFINED CMAKE_RC_PREPROCESSOR)
         set(CMAKE_DEPFILE_FLAGS_RC "-clang:-MD -clang:-MF -clang:<DEPFILE>")
-        set(CMAKE_RC_COMPILE_OBJECT "${CMAKE_COMMAND} -E cmake_llvm_rc <SOURCE> <OBJECT>.pp <${CMAKE_RC_PREPROCESSOR}> <DEFINES> -DRC_INVOKED <INCLUDES> <FLAGS> -E <SOURCE> ++ <CMAKE_RC_COMPILER> <DEFINES> -I <SOURCE_DIR> <INCLUDES> /fo <OBJECT> <OBJECT>.pp")
+        set(CMAKE_RC_COMPILE_OBJECT "${CMAKE_COMMAND} -E cmake_llvm_rc <SOURCE> <OBJECT>.pp <${CMAKE_RC_PREPROCESSOR}> <DEFINES> -DRC_INVOKED <INCLUDES> <FLAGS> -E -- <SOURCE> ++ <CMAKE_RC_COMPILER> <DEFINES> -I <SOURCE_DIR> <INCLUDES> /fo <OBJECT> <OBJECT>.pp")
         if(CMAKE_GENERATOR STREQUAL "Ninja")
           set(CMAKE_NINJA_CMCLDEPS_RC 0)
           set(CMAKE_NINJA_DEP_TYPE_RC gcc)
diff --git a/Modules/Platform/Windows-MSVC.cmake b/Modules/Platform/Windows-MSVC.cmake
index e272da9..173ef40 100644
--- a/Modules/Platform/Windows-MSVC.cmake
+++ b/Modules/Platform/Windows-MSVC.cmake
@@ -333,6 +333,14 @@ macro(__windows_compiler_msvc lang)
   set(CMAKE_LINK_PCH ON)
   if (CMAKE_${lang}_COMPILER_ID STREQUAL "Clang")
     set(CMAKE_PCH_PROLOGUE "#pragma clang system_header")
+
+    # macOS paths usually start with /Users/*. Unfortunately, clang-cl interprets
+    # paths starting with /U as macro undefines, so we need to put a -- before the
+    # input file path to force it to be treated as a path.
+    string(REPLACE "-c <SOURCE>" "-c -- <SOURCE>" CMAKE_${lang}_COMPILE_OBJECT "${CMAKE_${lang}_COMPILE_OBJECT}")
+    string(REPLACE "-c <SOURCE>" "-c -- <SOURCE>" CMAKE_${lang}_CREATE_PREPROCESSED_SOURCE "${CMAKE_${lang}_COMPILE_OBJECT}")
+    string(REPLACE "-c <SOURCE>" "-c -- <SOURCE>" CMAKE_${lang}_CREATE_ASSEMBLY_SOURCE "${CMAKE_${lang}_COMPILE_OBJECT}")
+
   elseif(MSVC_VERSION GREATER_EQUAL 1913)
     # At least MSVC toolet 14.13 from VS 2017 15.6
     set(CMAKE_PCH_PROLOGUE "#pragma system_header")
-- 
cgit v0.12