Kuba Mracek
Software Engineer at Apple Inc.
Cupertino, California, United States
Summary
🤩
Rockstar🎓
Top SchoolKuba Mracek is a seasoned software engineer with 13 years of experience specializing in developer tools and operating systems at Apple, working deeply on Apple Silicon Macs, Xcode, and macOS/iOS. He brings rare combined expertise in compilers (LLVM/Clang/Swift), sanitizers and debuggers (ASan, TSan, UBSan, LLDB), OS internals, and low-level assembly for x86 and arm64. His open-source contributions include extending LLDB and Clang to integrate AddressSanitizer and ThreadSanitizer support and advancing Swift’s embedded runtime—work that directly improves debugging and memory-safety tooling used across major projects. Known for tackling hard reliability and performance problems, he blends systems-level thinking with practical instrumentation and tooling to surface elusive bugs. Based in Cupertino with a Master’s in Computer Science from Charles University, he operates at the intersection of security, concurrency, and compiler/runtime engineering.
13 years of coding experience
7 years of employment as a software developer
Bachelor’s Degree, Computer Science, Bachelor’s Degree, Computer Science at Charles University in Prague, Faculty of Mathematics and PhysicsMaster’s Degree, Computer Science, Master’s Degree, Computer Science at Charles University in Prague
English, Czech
Github Skills (35)
debugging10
objective-c10
debug10
c-language10
runtimes10
memory-management10
run-time10
build-system10
cmake10
instrumentation10
c1110
development-tools10
addresssanitizer10
lldb10
c1710
Programming languages (7)
Github contributions (5)
apple/swift-lldb
Mar 2016 - Apr 2019
This is the version of LLDB that supports the Swift programming language & REPL.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:89 commits, 60 PRs, 40 pushes in 3 years 1 month
Contributions summary:Kuba primarily contributed to the LLDB debugger's support for ThreadSanitizer (TSan) and its integration with the Swift programming language. Their work involved implementing a new InstrumentationRuntime plugin, enhancing debugging support with features like breakpoint integration, extended backtrace retrieval, and thread ID renumbering. The user also addressed build issues in the CMake build system related to TSan, and improved thread name wording. Furthermore, the user added a test case for swift and provided location information for racy global variables in TSan reports.
lldbswift-programming-languagereplswift-programmingswift
llvm-mirror/lldb
Jun 2014 - Apr 2019
Project moved to: https://github.com/llvm/llvm-project
Role in this project:Backend Developer
Backend DeveloperContributions:72 commits in 4 years 10 months
Contributions summary:Kuba contributed significantly to the lldb project, specifically focusing on extending its functionality with AddressSanitizer (ASan) and ThreadSanitizer (TSan) support. They implemented plugins for both sanitizers, enabling the retrieval of memory and thread-related information during debugging. Their work included extracting, formatting, and displaying relevant data from ASan and TSan reports, and integrating it into the SB API for easy use by debuggers.
llvm
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