[PATCH] D134475: Add C++11 attribute msvc::constexpr

[Richard Dzenis via Phabricator via cfe-commits]

RIscRIpt updated this revision to Diff 515740.
RIscRIpt added a comment.

A proper implementation

In D134475#4224082 <https://reviews.llvm.org/D134475#4224082>, @erichkeane wrote:

> I don't have a good idea, I don't think any sort of RAII object is the right way (since it will be wrong on child calls/etc), and the ParentMap is definitely not the right way.  Perhaps just a flag for CheckConstexprFunction?  I've not spent too much time in this section of the compiler, so hopefully someone else can come along and help. I suspect it is a property of `CallStackFrame`?  But that already contains a link to the FucntionDecl, right?  As far as the 'on return statement', I think the bit on CallStackFrame/EvalInfo is probably what is necessary.



> But that already contains a link to the FucntionDecl, right?

Yes, but we need to know current context (whether we're in `[[msvc::constexpr]] return` statement).

> As far as the 'on return statement', I think the bit on CallStackFrame/EvalInfo is probably what is necessary.

That's what I ended-up doing. This was the most reasonable approach I could come-up with.

I added a property to `CallStackFrame`, because it's a property of current function: whether we are in valid context which permits evaluation of `[[msvc::constexpr]]`. Additionally I added `MSConstexprContextRAII` which is used in `case Stmt::AttributedStmtClass:` to alter the property.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D134475/new/

https://reviews.llvm.org/D134475

Files:
  clang/include/clang/Basic/Attr.td
  clang/include/clang/Basic/AttrDocs.td
  clang/include/clang/Basic/DiagnosticASTKinds.td
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/AST/ExprConstant.cpp
  clang/lib/Sema/SemaDecl.cpp
  clang/lib/Sema/SemaDeclAttr.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/lib/Sema/SemaStmtAttr.cpp
  clang/test/AST/msvc-attrs-invalid.cpp
  clang/test/AST/msvc-attrs.cpp
  clang/test/AST/msvc-constexpr-new.cpp
  clang/test/Misc/pragma-attribute-supported-attributes-list.test

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