rjmccall added inline comments.
================ Comment at: clang/include/clang/Basic/AttrDocs.td:4367 +This is useful for variables that are always written to before use where the +default zero initialization provided by the toolchain loader is expensive. + }]; ---------------- How about: > The ``loader_uninitialized`` attribute can be placed on global variables to > indicate that the variable does not need to be zero initialized by the loader. > On most targets, zero-initialization does not incur any additional cost. > For example, most general purpose operating systems deliberately ensure > that all memory is properly initialized in order to avoid leaking privileged > information from the kernel or other programs. However, some targets > do not make this guarantee, and on these targets, avoiding an unnecessary > zero-initialization can have a significant impact on load times and/or code > size. > > A declaration with this attribute is a non-tentative definition just as if it > provided an initializer. Variables with this attribute are considered to be > uninitialized in the same sense as a local variable, and the programs must > write to them before reading from them. If the variable's type is a C++ class > type with a non-trivial default constructor, or an array thereof, this > attribute > only suppresses the static zero-initialization of the variable, not the > dynamic > initialization provided by executing the default constructor. ================ Comment at: clang/lib/Sema/SemaDeclAttr.cpp:7436 + case ParsedAttr::AT_LoaderUninitialized: + handleLoaderUninitializedAttr(S, D, AL); + break; ---------------- JonChesterfield wrote: > aaron.ballman wrote: > > If you don't need any custom semantic checking, you can remove that > > function and instead call > > `handleSimpleAttribute<LoaderUninitializedAttr>(S, D, AL);` > I think this patch does need some custom semantic checking, I just haven't > been able to work out how to implement it. Specifically, the attribute is an > initializer, so > > `int foo __attribute__((loader_uninitialised)) = some_value;` > > should be a warning, as the = some_value is going to be ignored. This should be an error, not a warning, unless there's a specific need to be lenient. 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
