[edk2-devel] [PATCH V2 2/2] BaseTools: Factorize GCC flags

Thu Aug 27 14:55:11 UTC 2020

On 08/27/20 10:32, Pierre Gondois wrote:
> Hello Laszlo,
> I thought Leif wanted to revert this modification. Should I apply your requested changes, or should this patch be reverted?

The *other* patch in this series has indeed been reverted:

- original commit: dbd546a32d5a ("BaseTools: Add gcc flag to warn on
void* pointer arithmetic", 2020-07-21)

- revert: 91e4bcb313f0 ("Revert "BaseTools: Add gcc flag to warn on
void* pointer arithmetic"", 2020-07-24)

I'm not sure what the intent was ultimately with this patch though.
(I.e., keep it or revert it.) Personally I'm not calling for a revert;
I'd just like the "-Os" duplication to be eliminated. Also it doesn't
need to occur for this stable tag, just eventually.

Leif, please comment!

Thanks!
Laszlo

> 
> Regards,
> Pierre
> 
> -----Original Message-----
> From: Laszlo Ersek <lersek at redhat.com> 
> Sent: Wednesday, August 26, 2020 5:43 PM
> To: Pierre Gondois <Pierre.Gondois at arm.com>
> Cc: devel at edk2.groups.io; bob.c.feng at intel.com; liming.gao at intel.com; Tomas Pilar <Tomas.Pilar at arm.com>; nd <nd at arm.com>; Leif Lindholm (Nuvia address) <leif at nuviainc.com>; Ard Biesheuvel <Ard.Biesheuvel at arm.com>
> Subject: Re: [edk2-devel] [PATCH V2 2/2] BaseTools: Factorize GCC flags
> 
> On 07/22/20 13:03, Laszlo Ersek wrote:
>> Hi Pierre,
>>
>> On 07/07/20 10:35, PierreGondois wrote:
>>> From: Pierre Gondois <pierre.gondois at arm.com>
>>>
>>> GCC48_ALL_CC_FLAGS has no dependency on GCC_ALL_CC_FLAGS.
>>> By definition, there should be such dependency.
>>>
>>> The outcomes of this patch is that GCC48_ALL_CC_FLAGS and other 
>>> dependent configurations will inherit from the additional "-Os" flag.
>>> The "-Os" flag optimizes a build in size, not breaking any build. In 
>>> a gcc command line, the last optimization flag has precedence. This 
>>> means that this "-Os" flag will be overriden by a more specific 
>>> optimization configuration, provided that this more specific flag is 
>>> appended at the end of the CC_FLAGS.
>>>
>>> Signed-off-by: Pierre Gondois <pierre.gondois at arm.com>
>>> Suggested-by: Tomas Pilar <Tomas.Pilar at arm.com>
>>> ---
>>>
>>> The changes can be seen at: 
>>> https://github.com/PierreARM/edk2/commits/831_Add_gcc_flag_warning_v2
>>>
>>> Notes:
>>>     v2:
>>>      - Make GCC48_ALL_CC_FLAGS dependent on
>>>        GCC_ALL_CC_FLAGS. [Tomas]
>>>
>>>  BaseTools/Conf/tools_def.template | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/BaseTools/Conf/tools_def.template 
>>> b/BaseTools/Conf/tools_def.template
>>> index 
>>> 397b011ba38f97f81f314f8641ac8bb95d5a2197..a1fd27b1adba8769949b7d628d7
>>> fbed49fe24267 100755
>>> --- a/BaseTools/Conf/tools_def.template
>>> +++ b/BaseTools/Conf/tools_def.template
>>> @@ -1952,7 +1952,7 @@ DEFINE GCC_RISCV64_RC_FLAGS        = -I binary -O elf64-littleriscv   -B riscv
>>>  # GCC Build Flag for included header file list generation
>>>  DEFINE GCC_DEPS_FLAGS              = -MMD -MF $@.deps
>>>  
>>> -DEFINE GCC48_ALL_CC_FLAGS            = -g -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -ffunction-sections -fdata-sections -include AutoGen.h -fno-common -DSTRING_ARRAY_NAME=$(BASE_NAME)Strings
>>> +DEFINE GCC48_ALL_CC_FLAGS            = DEF(GCC_ALL_CC_FLAGS) -ffunction-sections -fdata-sections -DSTRING_ARRAY_NAME=$(BASE_NAME)Strings
>>>  DEFINE GCC48_IA32_X64_DLINK_COMMON   = -nostdlib -Wl,-n,-q,--gc-sections -z common-page-size=0x20
>>>  DEFINE GCC48_IA32_CC_FLAGS           = DEF(GCC48_ALL_CC_FLAGS) -m32 -march=i586 -malign-double -fno-stack-protector -D EFI32 -fno-asynchronous-unwind-tables -Wno-address
>>>  DEFINE GCC48_X64_CC_FLAGS            = DEF(GCC48_ALL_CC_FLAGS) -m64 -fno-stack-protector "-DEFIAPI=__attribute__((ms_abi))" -maccumulate-outgoing-args -mno-red-zone -Wno-address -mcmodel=small -fpie -fno-asynchronous-unwind-tables -Wno-address
>>>
>>
>> As the commit message states, this change makes GCC48_ALL_CC_FLAGS inherit "-Os".
>>
>> It is true that all the NOOPT_GCC flags override "-Os" with "-O0":
>>
>> NOOPT_GCC48_IA32_CC_FLAGS       = DEF(GCC48_IA32_CC_FLAGS) -O0
>> NOOPT_GCC48_X64_CC_FLAGS       = DEF(GCC48_X64_CC_FLAGS) -O0
>> NOOPT_GCC48_ARM_CC_FLAGS       = DEF(GCC48_ARM_CC_FLAGS) -O0
>> NOOPT_GCC48_AARCH64_CC_FLAGS   = DEF(GCC48_AARCH64_CC_FLAGS) -O0
>> NOOPT_GCC49_IA32_CC_FLAGS       = DEF(GCC49_IA32_CC_FLAGS) -O0
>> NOOPT_GCC49_X64_CC_FLAGS       = DEF(GCC49_X64_CC_FLAGS) -O0
>> NOOPT_GCC49_ARM_CC_FLAGS       = DEF(GCC49_ARM_CC_FLAGS) -O0
>> NOOPT_GCC49_AARCH64_CC_FLAGS     = DEF(GCC49_AARCH64_CC_FLAGS) -O0
>> NOOPT_GCC5_IA32_CC_FLAGS       = DEF(GCC5_IA32_CC_FLAGS) -O0
>> NOOPT_GCC5_X64_CC_FLAGS        = DEF(GCC5_X64_CC_FLAGS) -O0
>> NOOPT_GCC5_ARM_CC_FLAGS        = DEF(GCC5_ARM_CC_FLAGS) -O0
>> NOOPT_GCC5_AARCH64_CC_FLAGS    = DEF(GCC5_AARCH64_CC_FLAGS) -O0
>>
>> However, *some* of the DEBUG and RELEASE flags now have two "-Os" flags:
>>
>>   DEBUG_GCC48_IA32_CC_FLAGS       = DEF(GCC48_IA32_CC_FLAGS) -Os
>> RELEASE_GCC48_IA32_CC_FLAGS       = DEF(GCC48_IA32_CC_FLAGS) -Os -Wno-unused-but-set-variable
>>   DEBUG_GCC48_X64_CC_FLAGS       = DEF(GCC48_X64_CC_FLAGS) -Os
>> RELEASE_GCC48_X64_CC_FLAGS       = DEF(GCC48_X64_CC_FLAGS) -Os -Wno-unused-but-set-variable
>>   DEBUG_GCC49_IA32_CC_FLAGS       = DEF(GCC49_IA32_CC_FLAGS) -Os
>> RELEASE_GCC49_IA32_CC_FLAGS       = DEF(GCC49_IA32_CC_FLAGS) -Os -Wno-unused-but-set-variable -Wno-unused-const-variable
>>   DEBUG_GCC49_X64_CC_FLAGS       = DEF(GCC49_X64_CC_FLAGS) -Os
>> RELEASE_GCC49_X64_CC_FLAGS       = DEF(GCC49_X64_CC_FLAGS) -Os -Wno-unused-but-set-variable -Wno-unused-const-variable
>>   DEBUG_GCC5_IA32_CC_FLAGS       = DEF(GCC5_IA32_CC_FLAGS) -flto -Os
>> RELEASE_GCC5_IA32_CC_FLAGS       = DEF(GCC5_IA32_CC_FLAGS) -flto -Os -Wno-unused-but-set-variable -Wno-unused-const-variable
>>   DEBUG_GCC5_X64_CC_FLAGS        = DEF(GCC5_X64_CC_FLAGS) -flto -DUSING_LTO -Os
>> RELEASE_GCC5_X64_CC_FLAGS        = DEF(GCC5_X64_CC_FLAGS) -flto -DUSING_LTO -Os -Wno-unused-but-set-variable -Wno-unused-const-variable
>>
>> (The ARM and AARCH64 DEBUG/RELEASE GCC options don't seem to be 
>> affected, as they have relied on inherited -- not open-coded -- "-Os" 
>> options from much earlier. So now they do not suffer from this 
>> duplication.)
>>
>> The point of this patch was a kind of "normalization", so I think the work isn't complete until the duplication is undone, i.e., the explicit "-Os" flag is removed from the last twelve defines.
>>
>> Can you submit a follow-up patch please?
> 
> I have not received an answer, and I'm not aware of a follow-up patch being on the list; so now I've filed:
> 
> https://bugzilla.tianocore.org/show_bug.cgi?id=2928
> 
> Thanks
> Laszlo
> 

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