Re: [edk2-devel] [Patch] BaseTools tools_def.template: Add back -fno-pie option in GCC49 tool chain

["Laszlo Ersek" <lersek@redhat.com>]

(+Ard)

On 02/04/20 05:54, Liming Gao wrote:
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2502
> This option is required to make GCC49 tool chain work with the high
> version GCC compiler.
> 
> Cc: Bob Feng <bob.c.feng@intel.com>
> Signed-off-by: Liming Gao <liming.gao@intel.com>
> ---
>  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 feee2bbf16..d02424ae44 100755
> --- a/BaseTools/Conf/tools_def.template
> +++ b/BaseTools/Conf/tools_def.template
> @@ -1974,7 +1974,7 @@ DEFINE GCC48_ARM_ASLDLINK_FLAGS      = DEF(GCC_ARM_ASLDLINK_FLAGS) -Wl,--oformat
>  DEFINE GCC48_AARCH64_ASLDLINK_FLAGS  = DEF(GCC_AARCH64_ASLDLINK_FLAGS)
>  DEFINE GCC48_ASLCC_FLAGS             = DEF(GCC_ASLCC_FLAGS)
>  
> -DEFINE GCC49_IA32_CC_FLAGS           = DEF(GCC48_IA32_CC_FLAGS)
> +DEFINE GCC49_IA32_CC_FLAGS           = DEF(GCC48_IA32_CC_FLAGS) -fno-pic -fno-pie
>  DEFINE GCC49_X64_CC_FLAGS            = DEF(GCC48_X64_CC_FLAGS)
>  DEFINE GCC49_IA32_X64_DLINK_COMMON   = -nostdlib -Wl,-n,-q,--gc-sections -z common-page-size=0x40
>  DEFINE GCC49_IA32_X64_ASLDLINK_FLAGS = DEF(GCC49_IA32_X64_DLINK_COMMON) -Wl,--defsym=PECOFF_HEADER_SIZE=0 DEF(GCC_DLINK2_FLAGS_COMMON) -Wl,--entry,ReferenceAcpiTable -u ReferenceAcpiTable
> @@ -1997,7 +1997,7 @@ DEFINE GCC49_ARM_ASLDLINK_FLAGS      = DEF(GCC48_ARM_ASLDLINK_FLAGS)
>  DEFINE GCC49_AARCH64_ASLDLINK_FLAGS  = DEF(GCC48_AARCH64_ASLDLINK_FLAGS)
>  DEFINE GCC49_ASLCC_FLAGS             = DEF(GCC48_ASLCC_FLAGS)
>  
> -DEFINE GCC5_IA32_CC_FLAGS            = DEF(GCC49_IA32_CC_FLAGS) -fno-pic -fno-pie
> +DEFINE GCC5_IA32_CC_FLAGS            = DEF(GCC49_IA32_CC_FLAGS)
>  DEFINE GCC5_X64_CC_FLAGS             = DEF(GCC49_X64_CC_FLAGS)
>  DEFINE GCC5_IA32_X64_DLINK_COMMON    = DEF(GCC49_IA32_X64_DLINK_COMMON)
>  DEFINE GCC5_IA32_X64_ASLDLINK_FLAGS  = DEF(GCC49_IA32_X64_ASLDLINK_FLAGS)
> 

- What has changed relative to commit 11d0cd23dd1b ("BaseTools/tools_def
IA32: drop -no-pie linker option for GCC49", 2018-06-18)?

- Also, if we are reverting one half of 11d0cd23dd1b (the compiler
flags), shouldn't we then revert the other half too (the linker flags)?

- The commit message says, "work with the high version GCC compiler".
What does that mean? If it is 4.9.x, with x>2, then I agree the patch is
justified (because commit 11d0cd23dd1b was apparently made for 4.9.2).
But if the phrase stands for gcc8 or so (just an example), then I don't
think the patch is a good idea; users of gcc8 can just specify the GCC5
toolchain.

Ah, indeed, I need only look at TianoCore#2502:

"GCC49 tool chain meets with the build failure when GCC7.4 compiler".

So I think this approach is wrong. Unless there is a new gcc-4.9.x
release, i.e., after gcc-4.9.2, I think we still need commit
11d0cd23dd1b in place. And, please use GCC5 for gcc-7.4 -- is there a
problem with that?

Thanks
Laszlo