Disable Clang -Wtautological-constant-compare.
This is a recent Clang warning, but it's far too aggressive. The earlier
unsigned long silliness was worth fixing, but it otherwise complains on
32-bit platforms with:
if (some_size_t > 0xffffffff) {
...
}
which is unreasonable as, on 64-bit platforms, this check is meaningful
and requiring the programmer add ifdefs is error-prone. This matches
Chromium in https://crbug.com/767059.
Bug: chromium:767059
Change-Id: I0bb0f3a4b60f222e9d1b3c569471fbcf5518caed
Reviewed-on: https://boringssl-review.googlesource.com/23845
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index eb8717a..6674a41 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,11 @@
cmake_minimum_required (VERSION 2.8.11)
+# Report AppleClang separately from Clang. Their version numbers are different.
+# https://cmake.org/cmake/help/v3.0/policy/CMP0025.html
+if(POLICY CMP0025)
+ cmake_policy(SET CMP0025 NEW)
+endif()
+
# Defer enabling C and CXX languages.
project (BoringSSL NONE)
@@ -63,6 +69,18 @@
set(C_CXX_FLAGS "${C_CXX_FLAGS} -Wno-free-nonheap-object")
endif()
+ if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
+ NOT "6.0.0" VERSION_GREATER CMAKE_C_COMPILER_VERSION)
+ # Clang's -Wtautological-constant-compare is far too aggressive and does not
+ # account for, say, wanting the same code to work on both 32-bit and 64-bit
+ # platforms.
+ #
+ # Note "Clang" and "AppleClang" version differently, so we check for an
+ # exact match on the COMPILER_ID. As of writing, the warning is not in any
+ # release of AppleClang yet.
+ set(C_CXX_FLAGS "${C_CXX_FLAGS} -Wno-tautological-constant-compare -Wtautological-constant-out-of-range-compare")
+ endif()
+
if(CLANG OR NOT "7.0.0" VERSION_GREATER CMAKE_C_COMPILER_VERSION)
set(C_CXX_FLAGS "${C_CXX_FLAGS} -Wimplicit-fallthrough")
endif()
