clang thread-local compilation error on windows

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1

Hello, I am trying to compile some code to LLVM IR with a simple “__thread int x” but hitting this error:

test.cpp:1:1: error: thread-local storage is unsupported for the current target

I’m using both the -S and -emit-llvm options on clang, and was expecting to see “@x = thread_local global i32 0” come out of clang.

I am curious why clang even cares about this since its my understanding it woud just attach thread_local to the declaration and then allow me to handle it later on in llc to do the actual traget specific implementation. Can someone help clear where the thread-local implementation should go?

Thanks,
-Stephen

2

It's saying this because it knows that LLVM doesn't support thread
local storage on Windows. Although I believe this has changed
recently. The reason clang is reporting it is because in general it is
nicer for a user to get a nice diagnostic from clang instead of an
assert from inside codegen.

- Michael Spencer