Michael Ilseman
Compiler Engineer at Apple
San Francisco, California, United States
Summary
🤩
Rockstar🎓
Top SchoolMichael Ilseman is a compiler engineer with 15 years of systems and tooling experience, currently building compilers and developer infrastructure at Apple in San Francisco. His work spans core compiler projects (Clang/LLVM), Swift runtimes and tooling (LLDB, swift-corelibs-foundation, swift-package-manager, swift-clang) and low-level system libraries, reflecting deep expertise in parsing, diagnostics, codegen and string/runtime representations. He has a track record of pragmatic refactors and correctness-focused changes—silencing warnings, introducing attributes like ns_error_domain, and improving UTF-8 string handling in debuggers and runtimes. Earlier roles include shader compiler work at LunarG and language research at Runtime Verification, where he contributed a Haskell syntax definition for the K Framework. Colleagues rely on him to make subtle, high-impact improvements to complex codebases that improve toolchain robustness and developer ergonomics. He holds a B.S. in Computer Science from UIUC and combines research instincts with production-grade engineering.
16 years of coding experience
3 years of employment as a software developer
B.S, Computer Science, B.S, Computer Science at University of Illinois Urbana-Champaign
Github Skills (38)
debugging10
objective-c10
c-language10
string-format10
package-management10
madge10
foundation10
testing10
text-manipulation10
foundation-sites10
c1110
lldb10
refactor10
c1710
system-calls10
Programming languages (9)
Github contributions (5)
apple/swift-system
Sep 2020 - Aug 2021
Low-level system calls and types for Swift
Role in this project:
Back-end Developer
Back-end DeveloperContributions:6 releases, 165 reviews, 53 commits in 11 months
Contributions summary:Michael contributed significantly to the core infrastructure of the Swift System project, focusing on low-level system calls and types. Their initial work included the introduction of fundamental error handling with the Errno struct and the initial implementation of system call mocking and testing infrastructure. They later enhanced the project with Windows syscall adapters and Windows TLS mocking support. The user's work also involved refactoring to improve platform string handling and path normalization.
swiftsystem-callsfile-pathfile-descriptorposix
swiftlang/swift-corelibs-foundation
Mar 2016 - Feb 2019
The Foundation Project, providing core utilities, internationalization, and OS independence
Role in this project:Back-end Developer
Back-end DeveloperContributions:27 commits, 12 PRs, 6 pushes in 2 years 11 months
Contributions summary:Michael contributed to the `swift-corelibs-foundation` project, primarily focusing on code adjustments and refactoring. Their work involved silencing compiler warnings, adding explicit `@escaping` annotations, and removing deprecated code elements. They also contributed to the transition to a UTF-8 native String implementation.
tvostranslationinternationalizationfoundationindependence
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