Leif,
I also noticed we would need this flag for clang/Xcode too.
~/work/Compiler>clang -S void.c
~/work/Compiler>clang -S void.c -Wpointer-arith
void.c:4:14: warning: arithmetic on a pointer to void is a GNU extension
[-Wpointer-arith]
return Arg + 1;
~~~ ^
1 warning generated.
~/work/Compiler>cat void.c
void *
Test (void *Arg)
{
return Arg + 1;
}
Thanks,
Andrew Fish
> On Jul 22, 2020, at 11:05 AM, Leif Lindholm <[email protected]> wrote:
>
> Hi Bob,
>
> This patch also breaks about half of the ARM/AARCH64 platforms in
> edk2-platforms. I agree it should go in at a later stage, but for now,
> can we please revert it?
>
> Regards,
>
> Leif
>
> On Mon, Jul 20, 2020 at 04:10:27 +0000, Bob Feng wrote:
>> Reviewed-by: Bob Feng<[email protected]>
>>
>>
>> -----Original Message-----
>> From: PierreGondois <[email protected]>
>> Sent: Tuesday, July 7, 2020 4:35 PM
>> To: [email protected]
>> Cc: Pierre Gondois <[email protected]>; Feng, Bob C
>> <[email protected]>; Gao, Liming <[email protected]>;
>> [email protected]; [email protected]
>> Subject: [PATCH V2 1/2] BaseTools: Add gcc flag to warn on void* pointer
>> arithmetic
>>
>> From: Pierre Gondois <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>>
>> The changes can be seen at:
>> https://github.com/PierreARM/edk2/commits/831_Add_gcc_flag_warning_v2
>>
>> Notes:
>> v1:
>> - Add "-Wpointer-arith" gcc flag. [Pierre]
>> v2:
>> - Only add the flag for ARM and AARCH64. [Tomas]
>>
>> BaseTools/Conf/tools_def.template | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/BaseTools/Conf/tools_def.template
>> b/BaseTools/Conf/tools_def.template
>> index
>> 8aeb8a2a6417e41c5660cda5066f52adc8cc3089..397b011ba38f97f81f314f8641ac8bb95d5a2197
>> 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
>> @@ -1921,9 +1921,9 @@ NOOPT_*_*_OBJCOPY_ADDDEBUGFLAG =
>> --add-gnu-debuglink=$(DEBUG_DIR)/$(MODULE_N
>> 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_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
>> +DEFINE GCC_ARM_CC_FLAGS = DEF(GCC_ALL_CC_FLAGS) -Wpointer-arith
>> -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
>> DEFINE GCC_ARM_CC_XIPFLAGS = -mno-unaligned-access
>> -DEFINE GCC_AARCH64_CC_FLAGS = DEF(GCC_ALL_CC_FLAGS) -mlittle-endian
>> -fno-short-enums -fverbose-asm -funsigned-char -ffunction-sections
>> -fdata-sections -Wno-address -fno-asynchronous-unwind-tables
>> -fno-unwind-tables -fno-pic -fno-pie -ffixed-x18
>> +DEFINE GCC_AARCH64_CC_FLAGS = DEF(GCC_ALL_CC_FLAGS) -Wpointer-arith
>> -mlittle-endian -fno-short-enums -fverbose-asm -funsigned-char
>> -ffunction-sections -fdata-sections -Wno-address
>> -fno-asynchronous-unwind-tables -fno-unwind-tables -fno-pic -fno-pie
>> -ffixed-x18
>> DEFINE GCC_AARCH64_CC_XIPFLAGS = -mstrict-align -mgeneral-regs-only
>> DEFINE GCC_DLINK_FLAGS_COMMON = -nostdlib --pie
>> DEFINE GCC_DLINK2_FLAGS_COMMON =
>> -Wl,--script=$(EDK_TOOLS_PATH)/Scripts/GccBase.lds
>> --
>> 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
>>
>>
>>
>>
>
>
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