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✨ Feature: LLVM exception unwinding via setjmp - #54

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Tcode-Motion merged 2 commits into
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llvm-try-catch-18129513131942921509
Aug 25, 2026
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✨ Feature: LLVM exception unwinding via setjmp#54
Tcode-Motion merged 2 commits into
mainfrom
llvm-try-catch-18129513131942921509

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✨ What (the implementation):
Implemented try/catch and throw semantics for LLVM native code compilation inside compiler/llvm_backend/src/codegen.rs mapping to the runtime/native_runtime infrastructure.

🎯 Why (the problem solved):
TerminatorKind::Throw and Op::Try were left as stubs that simply evaluated as LLVMBuildUnreachable or skipped entirely when natively compiling TechScript projects, causing unexpected aborts and lack of exception handling.

🔬 Execution details:

  • Created a platform-agnostic 2048-byte aligned JmpBuf opaque struct in runtime/native_runtime to map FFI setjmp/longjmp.
  • Built thread-local un-winding tracking inside the native runtime (ts_try_push, ts_try_pop, ts_throw, ts_get_exception).
  • In Op::Try, split the basic block to add the conditional exception jump via setjmp check with correct memory cleanup via ts_try_free.
  • Validated correct Windows _setjmp arity (2 params) and linked the LLVM returns_twice attribute to setjmp to prevent miscompilations.

PR created automatically by Jules for task 18129513131942921509 started by @Tcode-Motion

Added support for try/catch exception unwinding in the LLVM backend.
A pragmatic `setjmp`/`longjmp` FFI approach is utilized in the native runtime instead of DWARF personality functions to quickly restore stack frame states.
- Created `JmpBuf` for thread-local unwinding state.
- Generated correct branching logic within the `Op::Try` IR codegen and exception fallback mappings.
- Cleaned up allocated buffer handles using `ts_try_free`.
- Updated test cases to reflect success.
Co-authored-by: Tcode-Motion <188012755+Tcode-Motion@users.noreply.github.com>
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@Tcode-Motion
Tcode-Motion marked this pull request as ready for review August 25, 2026 10:23
@Tcode-Motion
Tcode-Motion merged commit 909fd26 into mainAug 25, 2026
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