It looks like GCC5_X64_CC_FLAGS pick up GCC48_ALL_CC_FLAGS as the lowest level flag list, so this change will not apply to compilations on the X64 architecture.
That said, I suspect that X64 architecture will likely have the biggest issues with disallowing void* arithmetic, so we either: 1. Mend the tools_def to make GCC48_ALL_CC_FLAGS pick up GCC_ALL_CC_FLAGS, rerun tests and CI to make sure this change does not break large parts of existing codebase. 2. Move this change to ARM/AARCH64 low level CC_FLAGS lists to explicitly exclude this change from X64 architecture compilation. Cheers, Tom NB. I personally like the void* arithmetic GNU C extension - I like being able to combine the implicit pointer casts with raw pointer arithmetic. But I can appreciate if we want to keep the codebase strict. -----Original Message----- From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of PierreGondois via groups.io Sent: 30 June 2020 16:24 To: devel@edk2.groups.io Cc: Pierre Gondois <pierre.gond...@arm.com>; bob.c.f...@intel.com; liming....@intel.com; nd <n...@arm.com> Subject: [edk2-devel] [PATCH v1] BaseTools: Add gcc flag to warn on void* pointer arithmetic From: Pierre Gondois <pierre.gond...@arm.com> By default, gcc allows void* pointer arithmetic. This is a GCC extension. However: - the C reference manual states that void* pointer "cannot be operands of addition or subtraction operators". Cf s5.3.1 "Generic Pointers"; - Visual studio compiler treat such operation as an error. To prevent such pointer arithmetic, the "-Wpointer-arith" flag should be set for all GCC versions. The "-Wpointer-arith" allows to: "Warn about anything that depends on the "size of" a function type or of void. GNU C assigns these types a size of 1, for convenience in calculations with void * pointers and pointers to functions." This flag is available since GCC2.95.3 which came out in 2001. Signed-off-by: Pierre Gondois <pierre.gond...@arm.com> --- The changes can be seen at: https://github.com/PierreARM/edk2/commits/831_Add_gcc_flag_warning_v1 Notes: v1: - Add "-Wpointer-arith" gcc flag. [Pierre] BaseTools/Conf/tools_def.template | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/BaseTools/Conf/tools_def.template b/BaseTools/Conf/tools_def.template index 8aeb8a2a6417e41c5660cda5066f52adc8cc3089..fba71665d6ade4dad08a5a0c343f357fd413a8a4 100755 --- a/BaseTools/Conf/tools_def.template +++ b/BaseTools/Conf/tools_def.template @@ -1,7 +1,7 @@ # # Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR> # Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR> -# Portions copyright (c) 2011 - 2019, ARM Ltd. All rights reserved.<BR> +# Portions copyright (c) 2011 - 2020, ARM Ltd. All rights reserved.<BR> # Copyright (c) 2015, Hewlett-Packard Development Company, L.P.<BR> # (C) Copyright 2020, Hewlett Packard Enterprise Development LP<BR> # Copyright (c) Microsoft Corporation @@ -1918,7 +1918,7 @@ NOOPT_*_*_OBJCOPY_ADDDEBUGFLAG = --add-gnu-debuglink=$(DEBUG_DIR)/$(MODULE_N *_*_*_DTCPP_PATH = DEF(DTCPP_BIN) *_*_*_DTC_PATH = DEF(DTC_BIN) -DEFINE GCC_ALL_CC_FLAGS = -g -Os -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -include AutoGen.h -fno-common +DEFINE GCC_ALL_CC_FLAGS = -g -Os -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wpointer-arith -Wno-array-bounds -include AutoGen.h -fno-common DEFINE GCC_IA32_CC_FLAGS = DEF(GCC_ALL_CC_FLAGS) -m32 -malign-double -freorder-blocks -freorder-blocks-and-partition -O2 -mno-stack-arg-probe DEFINE GCC_X64_CC_FLAGS = DEF(GCC_ALL_CC_FLAGS) -mno-red-zone -Wno-address -mno-stack-arg-probe DEFINE GCC_ARM_CC_FLAGS = DEF(GCC_ALL_CC_FLAGS) -mlittle-endian -mabi=aapcs -fno-short-enums -funsigned-char -ffunction-sections -fdata-sections -fomit-frame-pointer -Wno-address -mthumb -mfloat-abi=soft -fno-pic -fno-pie -- 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)' -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#61860): https://edk2.groups.io/g/devel/message/61860 Mute This Topic: https://groups.io/mt/75215666/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
