Bug 1491849 - Disable C5045 only if optimization is disabled. r=dmajor

I also changed security/certverifier/moz.build a bit while I am here:
* Using '-Xclang' to pass through '-Wall' on clang-cl.
* Now clang-cl will take clang/gcc path because most '-wd****' options have no
  effect on clang-cl. '-wd4010' will have an effect, but we already have the
  corresponding clang/gcc option ('-Wno-unused-parameter').

--HG--
extra : source : df566a1bd9087cc0bfc03fe19fd9d21bf58f5d9c

security/certverifier/moz.build

@@ -60,13 +60,11 @@ TEST_DIRS += [
 
 if CONFIG['CC_TYPE'] == 'clang-cl':
     # -Wall on clang-cl maps to -Weverything, which turns on way too
-    # much, so we're using -W4 instead, which is mapped to clang's
-    # -Wall -Wextra.
-    CXXFLAGS += ['-W4']
-else:
-    CXXFLAGS += ['-Wall']
+    # much, so we're passing through -Wall using -Xclang.
+    CXXFLAGS += ['-Xclang']
+CXXFLAGS += ['-Wall']
 
-if CONFIG['CC_TYPE'] in ('msvc', 'clang-cl'):
+if CONFIG['CC_TYPE'] == 'msvc':
     # -Wall with Visual C++ enables too many problematic warnings
     CXXFLAGS += [
         '-wd4324', # structure was padded due to __declspec(align())
@@ -98,6 +96,13 @@ if CONFIG['CC_TYPE'] in ('msvc', 'clang-cl'):
         '-wd4820', # 'bytes' bytes padding added after construct 'member_name'
     ]
 
+    # Disable Spectre diagnostics only if optimization is disabled.
+    if not CONFIG['MOZ_OPTIMIZE']:
+        CXXFLAGS += [
+            '-wd5045', # Compiler will insert Spectre mitigation for memory
+                       # load if /Qspectre switch specified
+        ]
+
     # MSVC 2010's headers trigger these
     CXXFLAGS += [
         '-wd4548', # expression before comma has no effect; ...
@@ -129,7 +134,7 @@ if CONFIG['CC_TYPE'] in ('msvc', 'clang-cl'):
         '-wd4946', # reinterpret_cast used between related types
     ]
 
-if CONFIG['CC_TYPE'] in ('clang', 'gcc'):
+if CONFIG['CC_TYPE'] in ('clang', 'clang-cl', 'gcc'):
     CXXFLAGS += [
         '-Wextra',
         '-Wunreachable-code',

security/pkix/test/gtest/moz.build

@@ -70,6 +70,12 @@ elif CONFIG['CC_TYPE'] == 'msvc':
     # declaration of '*' hides class member
     '-wd4458',
   ]
+  # Disable Spectre diagnostics only if optimization is disabled.
+  if not CONFIG['MOZ_OPTIMIZE']:
+    CXXFLAGS += [
+      '-wd5045', # Compiler will insert Spectre mitigation for memory load if
+                 # /Qspectre switch specified
+    ]
 
 if CONFIG['CC_TYPE'] == 'clang-cl':
     AllowCompilerWarnings()  # workaround for bug 1090497