gccrs: Recognize cfi_encoding attribute and warn about its status
gccrs now recognizes the `cfi_encoding` attribute but warns that it's not yet functional, pending upstream review.
This commit updates gccrs to recognize the #[cfi_encoding] attribute. While the attribute is now parsed and acknowledged, the compiler issues a warning indicating that it does not currently perform any action. This is because the functionality relies on an upstream patchset that is still under review. The change includes adding the attribute to the feature gate definitions and test cases.
In Details
gccrs now recognizes the #[cfi_encoding] attribute. The FeatureGate infrastructure has been updated to include this attribute, and a visitor warns the user that it is not yet implemented, pending an upstream patch review. This is a step towards supporting DWARF Call Frame Information encodings in Rust code compiled by GCC.
- cfi_encoding
- Likely refers to an attribute in Rust that influences how Call Frame Information (CFI) is generated. CFI is used by debuggers to unwind the call stack.
- DWARF
- A debugging data format used by many Unix and Unix-like systems. It stores information about variables, types, and code structure to aid debuggers.
- FeatureGate
- A mechanism within GCC (and gccrs) that allows for the experimental or conditional enabling/disabling of language features. It helps manage the introduction of new language constructs.
- attribute
- In Rust, attributes are metadata attached to code elements (like functions or structs) using
#[...]syntax. They control various aspects of compilation, behavior, or code generation.