JonChesterfield added a comment. In D74361#1879559 <https://reviews.llvm.org/D74361#1879559>, @rjmccall wrote:
> This will need to impact static analysis and the AST, I think. Local > variables can't be redeclared, but global variables can, so disallowing > initializers syntactically when the attribute is present doesn't necessarily > stop other declarations from defining the variable. Also, you need to make > the attribute mark something as a definition, the same way that e.g. the > alias attribute does. Also, this probably ought to disable the > default-initialization of non-trivial types in C++, in case that's not > already done. I would like this to be the case but am having a tough time understanding how sema works. VarDecl::hasInit() looked promising but doesn't appear to indicate whether there is a syntactic initialiser (e.g. = 10) present. I will continue to investigate. Codegen appears to be working fine. In D74361#1880904 <https://reviews.llvm.org/D74361#1880904>, @jfb wrote: > The current uninitialized attribute fits the model C and C++ follow for > attributes: they have no semantic meaning for a valid program, in that a > compiler can just ignore them and (barring undefined behavior) there's no > observable effect to the program. This updated semantic changes the behavior > of a valid C and C++ program, because the standards specify the value of > uninitialized globals and TLS. I'd much rather have a separate attribute, say > `no_zero_init`, to explicitly say what this does. This proposed attribute can similarly be ignored without observable semantic effect. Instead of an IR undef variable, we would have an IR zeroinitialized variable, which is a legitimate implementation choice for undef. Adding the attribute to an existing program will, in general, change its meaning - but that's also true of other attributes. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D74361/new/ https://reviews.llvm.org/D74361 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
