[PATCH] D127762: [Clang][AArch64] Add/implement ACLE keywords for SME.

[Erich Keane via Phabricator via cfe-commits]

erichkeane added a subscriber: ChuanqiXu.
erichkeane added inline comments.


================
Comment at: clang/include/clang/AST/Type.h:3940
+    /// on declarations and function pointers.
+    unsigned AArch64SMEAttributes : 8;
+
----------------
sdesmalen wrote:
> erichkeane wrote:
> > sdesmalen wrote:
> > > erichkeane wrote:
> > > > sdesmalen wrote:
> > > > > erichkeane wrote:
> > > > > > We seem to be missing all of the modules-storage code for these.  Since this is modifying the AST, we need to increment the 'breaking change' AST code, plus add this to the ASTWriter/ASTReader interface.
> > > > > > Since this is modifying the AST, we need to increment the 'breaking change' AST code
> > > > > Could you give me some pointers on what you expect to see changed here? I understand your point about adding this to the ASTWriter/Reader interfaces for module-storage, but it's not entirely clear what you mean by "increment the breaking change AST code". 
> > > > > 
> > > > > I see there is also an ASTImporter, I guess this different from the ASTReader?
> > > > > 
> > > > > Please apologise my ignorance here, I'm not as familiar with the Clang codebase.
> > > > See VersionMajor here: https://clang.llvm.org/doxygen/ASTBitCodes_8h_source.html
> > > > 
> > > > Yes, ASTReader/ASTWriter and ASTImporter are different unfortunately.  I'm not completely sure of the difference, but doing this patch changing the type here without doing those will break modules.
> > > So I tried to create some tests for this (see clang/test/AST/ast-dump-sme-attributes.cpp) and realised that the serialization/deserialization works out-of-the-box.
> > > 
> > > Does that mean all is needed is an increment of the VERSION_MAJOR or VERSION_MINOR number?
> > So its not just ast-dump that matters, it is what happens when these functions are exported from a module, and imported from another?  Unless you make changes to those areas, this SME stuff will be lost, since you're making it part of the type.
> Hi @erichkeane I've added a test for module export/import and was surprised to see this work without any additional changes. Do you think the added test is correct/sufficient to show that this works?
I don't have a good idea of that, I know little about our modules implementation.  Perhaps @ChuanqiXu knows?


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