wasm2c: Reset the segment register after call_indirect as the register may have changed #2490
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@sbc100 Please have a look when you have a chance |
…r may have changed
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Would it be possible to share more context on when/why this is necessary? E.g., why reset it after a call_indirect but not an ordinary call? |
Sure thing. The call indirect has the potential to invoke arbitrary host functions (because function table could be imported and thus have entries set by the host), while a direct call is mostly reserved for other wasm2c generated code. For the call indirect, the code we have today works fine if the invoked host functions either (1) don't modify %gs or (2) modify and restore %gs. But if the invoked host function clobbers %gs, this poses an issue. There are potential edge cases where this could happen --- for instance in some debug/sanitizer flags are used. Resetting the values after a call indirect is the straightforward fix. |
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