Mark symbols as used, fix warnings

[idigdoug]

Compiler is optimizing-away some event symbols, breaking registration. This causes a link error (when there are zero events) and runtime failures (due to zero events getting registered). Fix by marking these symbols as #[used].

Also fix a few clippy warnings.

tests.rs:

• For clarity, name the "unregister-on-drop" object based on the PROVn that it is unregistering.

event_generator.rs:

• Add #[used] to the _EH_TRACEPOINT_PTR symbol so that it is not optimized-away so we can use it when registering the provider.
• Clippy is warning about unnecessary use of unsafe, so remove unsafe{ ... } from the generated code.

provider_generator.rs:

• Add #[used] to the _eh_define_provider_MY_PROVIDER symbol so that it is not optimized-away so we don't get linker errors on a provider with no events.
• Clippy is warning about static_mut_refs so suppress the warning.

Cargo.toml:

• The other projects work on 1.64+, so use that as the baseline.

perf_abi.rs:

• const transmute_copy is not supported until 1.74. Nobody really benefits from this being const, so remove the const.

[Copilot]

Pull request overview

This PR fixes a critical compiler optimization issue where event symbols were being optimized away, causing link errors and runtime failures. The fix adds #[used] attributes to prevent optimization and addresses several clippy warnings.

Key Changes:

• Added #[used] attributes to _EH_TRACEPOINT_PTR and _eh_define_provider_MY_PROVIDER symbols to prevent compiler optimization
• Removed unnecessary unsafe blocks in event_generator.rs based on clippy warnings
• Lowered rust-version requirement from 1.74 to 1.64 for consistency with other crates

Reviewed changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tracepoint_decode/src/perf_abi.rs	Removed const from from_bytes function (const transmute_copy requires rustc 1.74+)
tracepoint_decode/src/enumerator.rs	Fixed documentation indentation for consistency
tracepoint_decode/Cargo.toml	Lowered rust-version from 1.74 to 1.64 to match other crates
eventheader_macros/src/provider_generator.rs	Added #[used] attribute to prevent symbol optimization and #[allow(static_mut_refs)] to suppress warnings
eventheader_macros/src/event_generator.rs	Added #[used] attribute and removed unnecessary unsafe block
eventheader_dynamic/src/builder.rs	Fixed documentation indentation for consistency
eventheader/tests/tests.rs	Renamed variable from _u to _u1 for clarity that it relates to PROV1

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.