CMake: try to match Clang warning options when building with clang-cl on Windows

Change-Id: I24d6201adfd356f791458393d69be0b088814a0f
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/49320
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Auto-Submit: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>

CMakeLists.txt

@@ -155,11 +155,7 @@ function(tint_default_compile_options TARGET)
   target_compile_definitions(${TARGET} PUBLIC
       -DTINT_BUILD_WGSL_WRITER=$<BOOL:${TINT_BUILD_WGSL_WRITER}>)
 
-  if (${COMPILER_IS_LIKE_GNU})
-    target_compile_options(${TARGET} PRIVATE
-      -std=c++14
-      -fno-exceptions
-      -fno-rtti
+  set(COMMON_GNU_OPTIONS
     -Wall
     -Werror
     -Wextra
@@ -167,12 +163,9 @@ function(tint_default_compile_options TARGET)
     -Wno-padded
     -Wno-switch-enum
     -Wno-unknown-pragmas
-      -pedantic-errors
   )
 
-    if (("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang") OR
-        ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang"))
-      target_compile_options(${TARGET} PRIVATE
+  set(COMMON_CLANG_OPTIONS
     -Wno-c++98-compat
     -Wno-c++98-compat-pedantic
     -Wno-format-pedantic
@@ -182,6 +175,21 @@ function(tint_default_compile_options TARGET)
     -Wno-used-but-marked-unused
     -Weverything
   )
+
+  if (${COMPILER_IS_LIKE_GNU})
+    target_compile_options(${TARGET} PRIVATE
+      -std=c++14
+      -fno-exceptions
+      -fno-rtti
+      -pedantic-errors
+      ${COMMON_GNU_OPTIONS}
+    )
+
+    if (("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang") OR
+        ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang"))
+      target_compile_options(${TARGET} PRIVATE
+        ${COMMON_CLANG_OPTIONS}
+      )
     endif()
 
     if (${TINT_ENABLE_MSAN})
@@ -231,6 +239,20 @@ function(tint_default_compile_options TARGET)
       /wd5026
       /wd5027
     )
+
+    # When building with clang-cl on Windows, try to match our clang build
+    # options as much as possible.
+    if (COMPILER_IS_CLANG_CL)
+      target_compile_options(${TARGET} PRIVATE
+        ${COMMON_GNU_OPTIONS}
+        ${COMMON_CLANG_OPTIONS}
+        # Disable warnings that are usually disabled in downstream deps for
+        # gcc/clang, but aren't for clang-cl.
+        -Wno-global-constructors
+        -Wno-zero-as-null-pointer-constant
+        -Wno-shorten-64-to-32
+      )
+    endif()
   endif()
 
 endfunction()