Turn on well defined signed integer overflow

clang and gcc assume that signed integers never overflow.
This leads to unexpected bugs when optimizer removes bound checks etc.

Bug: 27703278
Bug: 22715185
Change-Id: Iab4c884fa190d05c0ac9236d01eeeb190e765e69

diff --git a/Android.mk b/Android.mk
index 3baf349..e02deff 100644 (file)
--- a/Android.mk
+++ b/Android.mk
@@ -895,7 +895,7 @@ LOCAL_CFLAGS += \
        $(deqp_compile_flags)
 
 LOCAL_SDK_VERSION := 9
-LOCAL_CPPFLAGS += -Wno-non-virtual-dtor
+LOCAL_CPPFLAGS += -Wno-non-virtual-dtor -fwrapv
 LOCAL_NDK_STL_VARIANT := gnustl_static
 LOCAL_RTTI_FLAG := -frtti -fexceptions
 LOCAL_MULTILIB := both

diff --git a/framework/delibs/cmake/CFlags.cmake b/framework/delibs/cmake/CFlags.cmake
index ff25740..98f0252 100644 (file)
--- a/framework/delibs/cmake/CFlags.cmake
+++ b/framework/delibs/cmake/CFlags.cmake
@@ -49,6 +49,10 @@ if (DE_COMPILER_IS_GCC OR DE_COMPILER_IS_CLANG)
        set(CMAKE_C_FLAGS                       "${CMAKE_C_FLAGS} ${TARGET_FLAGS} ${WARNING_FLAGS} -ansi -pedantic ")
        set(CMAKE_CXX_FLAGS                     "${CMAKE_CXX_FLAGS} ${TARGET_FLAGS} ${WARNING_FLAGS}")
 
+       # Force compiler to generate code where integers have well defined overflow
+       # Turn on -Wstrict-overflow=5 and check all warnings before removing
+       set(CMAKE_C_FLAGS                       "${CMAKE_C_FLAGS} -fwrapv")
+       set(CMAKE_CXX_FLAGS                     "${CMAKE_CXX_FLAGS} -fwrapv")
 elseif (DE_COMPILER_IS_MSC)
        # Compiler flags for msc