For the trace recorder, use a wrapper function with the PreserveAll ABI. #293
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vext01
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Dec 10, 2025
| llvm::Function *TraceFunc = Function::Create( | ||
| FType, llvm::Function::InternalLinkage, YK_TRACE_FUNCTION_WRAPPER, M); | ||
| TraceFunc->setCallingConv(llvm::CallingConv::PreserveAll); | ||
| TraceFunc->addFnAttr(YK_OUTLINE_FNATTR); |
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As is often the case: raise a PR, spot a potential tweak.
I'm just wondering if I should mark the wrapper noinline...
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I don't think we mind if it's inlined: in a sense, we do the "right thing" no matter which stack frame we run things in.
[That said, my guess would be that LLVM won't inline functions with this ABI. But I could be wrong about that.]
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OK, shall we try this as-is then?
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We use a wrapper so we can use an ABI that disrupts register allocation in the interpreter code to a lesser extent. The wrapper is required because the actual recorder function is defined in the JIT runtime's shared object and we can't change the ABI for library calls. Benchmarking suggests some decent speedup for a handful of benchmarks, mostly in the 2%-10% range.
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Force pushed a fix. |
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We use a wrapper so we can use an ABI that disrupts register allocation in the interpreter code to a lesser extent. The wrapper is required because the actual recorder function is defined in the JIT runtime's shared object and we can't change the ABI for library calls.
Benchmarking suggests some decent speedup for a handful of benchmarks, mostly in the 2%-10% range.