Hiya folks! I'm David and I work on rust-analyzer, which is a language server for Rust similar to sourcekit-lsp. I'm using the new Instruments profiling tooling functionality in Xcode 16.3 and Xcode 26 (Processor Trace and CPU Counters) to profile our trait solver/type checker. While I've been able to use the new CPU Counters instrument successfully (the CPU Bottleneck feature is incredible! Props to the team!), I've been unable to make use of the Processor Trace instrument.
Instruments gives me the error message "Processor Trace cannot profile this process without proper permissions". The diagnostic suggests adding the com.apple.security-get-task-allow entitlement to the code I'm trying to profile, or ensure that the build setting CODE_SIGN_INJECT_BASE_ENTITLEMENTS = YES is enabled in Xcode.
Unfortunately, I don't know how I can add that entitlement to a self-signed binary produced by Cargo and I'm not using Xcode for somewhat obvious reasons.
Here's some information about my setup:
Instruments Version 26.0 (17A5241e)
I'm on an 14" MacBook Pro with M4 Pro. It's running macOS Version 26.0 Beta (25A5295e).
I've enabled the "Processor Trace" feature in "Developer Tools" and even added the Instruments application to "Developer Tools".
As a last-ditch effort before posting this, I disabled SIP on my Mac. Didn't help.
To reproduce my issue:
Get Rust via https://rustup.rs/.
Clone rust-analyzer: git clone https://github.com/rust-lang/rust-analyzer.git.
cd rust-analyzer
Run cargo test --package hir-ty --lib --profile=dev-rel -- tests::incremental::add_struct_invalidates_trait_solve --exact --show-output. By default, this command will output a bunch of build progress with the output containing something like Running unittests src/lib.rs (target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe).
I take the absolute path of that hir_ty-$SOME-HASH string (in my case, it looks like /Users/dbarsky/Developer/rust-analyzer/target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe) and add it to the "Launch" profile. To the arguments section, I add --exact tests::incremental::add_struct_invalidates_trait_solve.
I then try to record/profile via Instruments, but then I get the error message I shared above.
Below is output of codesign -dvvv:
❯ codesign -dvvv target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe
Executable=/Users/dbarsky/Developer/rust-analyzer/target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe
Identifier=hir_ty-f1dbf1b1d36575fe
Format=Mach-O thin (arm64)
CodeDirectory v=20400 size=140368 flags=0x20002(adhoc,linker-signed) hashes=4383+0 location=embedded
Hash type=sha256 size=32
CandidateCDHash sha256=99e96c8622c7e20518617c66a7d4144dc0daef28
CandidateCDHashFull sha256=99e96c8622c7e20518617c66a7d4144dc0daef28f22fac013c28a784571ce1df
Hash choices=sha256
CMSDigest=99e96c8622c7e20518617c66a7d4144dc0daef28f22fac013c28a784571ce1df
CMSDigestType=2
CDHash=99e96c8622c7e20518617c66a7d4144dc0daef28
Signature=adhoc
Info.plist=not bound
TeamIdentifier=not set
Sealed Resources=none
Internal requirements=none
Any tips would be welcome! Additionally—and perhaps somewhat naively—I think I'd expect the Processor Trace instrument to just work with an adhoc-signed binary, as lldb and friends largely do—I'm not sure that such a high barrier for CPU perf counters is warranted, especially on an adhoc-signed binary.