Re: [PATCH 4/4] BaseTools: resolve initialization order errors in VfrFormPkg.h

[Zenith432 <zenith432@users.sourceforge.net>]

On 10/12/2017 03:52 PM, Gao, Liming wrote:
> I think these patches resolves CLANG build issues in BaseTools. Do you verify them with GCC or VS tool chain?
> 
GCC 7.2 does not give any of the warnings generated by clang while compiling BaseTools.
After applying the 4 BaseTools patches, it still does not give any warnings (or errors).
I don't have VS toolchain to try on.

For VfrFormPkg.h, there is simpler solution to surround all the offending code in

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wuninitialized"
<offending code>
#pragma clang diagnostic pop

I sent you this option last week, you said you prefer to resolve the reason for the "-Wuninitialized".
The reason is the attempt in 100 or so derived classes to force an initialization order different than C++.  It's 
undefined behavior.  Any resolution for the undefined behavior involves changing those 100 derived classes, so a massive 
code change.  The existing code works, it's just an attempt to get around standard C++ initialization order.  Clang 
wants to give pedantic warnings, but can be silenced if the "undefined behavioral" code is known to work.

The other 3 BaseTools patches are rather small.

Also, with the VA_START(Args, BOOLEAN) bug (bug 741), there is an option of silencing clang locally around the offending 
statement
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wvarargs"
VA_START(Args, Iso639Language);
#pragma clang diagnostic pop

And then remove global silencing of this warning in tools_def.txt.  That way any other not yet considered warnings will 
be caught in the future.

It's up to you how to go about it...  big code changes, silencing warning locally or silencing warning globally.