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Compiling with optimizations disabled results in runtime error #57
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unlikely to be fixed. IIRC llvm requires at least -O2
I see. Thank you for the reply! Is there any online resources that explain why this is the case?
Can't find anything now. Heck maybe I dreamed the whole thing up, or it has been fixed since Iooked at it 4 years ago?
But as I remember, llvm used some... uh... not so sound things that break under -O0.
Maybe @michaliskok can weigh in and provide some clarity
Also just for the sake of it, try downgrading to LLVM 15.0.0
This took embarrassingly long but here's a possible explanation.
First, I could only reproduce this in macOS. I am not aware of LLVM having issues with
-O0, but the crash anyway indicates that this is some issue in how internal genmc functions are handled.The precise cause is still a bit vague to me, but the cause of the crashes seems to be that some function calls that are normally resolved internally got offloaded to some LLVM-provided utils.
If a patch like this fixes the crashes, I'll merge something similar in the next release.
diff --git a/src/Runtime/Interpreter.h b/src/Runtime/Interpreter.h index c8d9b670..3694f0ab 100644 --- a/src/Runtime/Interpreter.h +++ b/src/Runtime/Interpreter.h @@ -585,11 +585,14 @@ public: void visitSelectInst(SelectInst &I); void visitCallInstWrapper(CallInstWrapper CIW); -#if LLVM_VERSION_MAJOR < 11 - void visitCallSite(CallSite CS) { visitCallInstWrapper(CallInstWrapper(CS)); } -#else +// #if LLVM_VERSION_MAJOR < 11 +// void visitCallSite(CallSite CS) { visitCallInstWrapper(CallInstWrapper(CS)); } +// #else void visitCallBase(CallBase &CB) { visitCallInstWrapper(CallInstWrapper(CB)); } -#endif +// #endif + void visitCallInst(CallInst &I) { visitCallInstWrapper(CallInstWrapper(I)); } + void visitInvokeInst(InvokeInst &I) { visitCallInstWrapper(CallInstWrapper(I)); } + void visitCallBrInst(CallBrInst &I) { visitCallInstWrapper(CallInstWrapper(I)); }
When running a genmc executable compiled with optimizations disabled, I get a runtime error.
When running genmc with the default compiler flags, everything runs smoothly.
How to reproduce:
autoreconf -ito generate the configure script./configure AR=llvm-ar CXXFLAGS="-O0 -g"to generate Makefilemake genmcto generate genmc executable./genmc --print-exec-graphs tests/correct/litmus/LB2/variants/lb0.coutputs:
In contrast the same steps except for
3)
./configure AR=llvm-aroutputs
I am using MacOS 14, llvm@15 installed