Add support for __declspec(nocf).

__declspec(nocf) syntax was added in https://reviews.llvm.org/D72167
and annotates that checks should not be added on indirect calls
within that function.

BUG=chromium:584575

Change-Id: Ib2e2d2a827186a9c1fd3de15356b2b04d6a69e49
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2270707Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68590}

src/base/macros.h

@@ -176,7 +176,14 @@ V8_INLINE Dest bit_cast(Source const& source) {
 
 // DISABLE_CFI_ICALL -- Disable Control Flow Integrity indirect call checks,
 // useful because calls into JITed code can not be CFI verified.
+#ifdef V8_OS_WIN
+// On Windows, also needs __declspec(guard(nocf)) for CFG.
+#define DISABLE_CFI_ICALL           \
+  V8_CLANG_NO_SANITIZE("cfi-icall") \
+  __declspec(guard(nocf))
+#else
 #define DISABLE_CFI_ICALL V8_CLANG_NO_SANITIZE("cfi-icall")
+#endif
 
 #if V8_CC_GNU
 #define V8_IMMEDIATE_CRASH() __builtin_trap()