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runtime safety for noasync function calls

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See #3157
This commit is contained in:
Andrew Kelley
2019-09-06 12:50:51 -04:00
parent 0a3c6dbda9
commit 7d303ae861
3 changed files with 37 additions and 0 deletions
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21
src/codegen.cpp
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@@ -923,6 +923,8 @@ static Buf *panic_msg_buf(PanicMsgId msg_id) {
return buf_create_from_str("frame too small");
case PanicMsgIdResumedFnPendingAwait:
return buf_create_from_str("resumed an async function which can only be awaited");
case PanicMsgIdBadNoAsyncCall:
return buf_create_from_str("async function called with noasync suspended");
}
zig_unreachable();
}
@@ -4067,6 +4069,25 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutable *executable, IrInstr
} else if (instruction->modifier == CallModifierNoAsync && !fn_is_async(g->cur_fn)) {
gen_resume(g, fn_val, frame_result_loc, ResumeIdCall);
if (ir_want_runtime_safety(g, &instruction->base)) {
LLVMValueRef awaiter_ptr = LLVMBuildStructGEP(g->builder, frame_result_loc,
frame_awaiter_index, "");
LLVMValueRef all_ones = LLVMConstAllOnes(usize_type_ref);
LLVMValueRef prev_val = gen_maybe_atomic_op(g, LLVMAtomicRMWBinOpXchg, awaiter_ptr,
all_ones, LLVMAtomicOrderingRelease);
LLVMValueRef ok_val = LLVMBuildICmp(g->builder, LLVMIntEQ, prev_val, all_ones, "");
LLVMBasicBlockRef bad_block = LLVMAppendBasicBlock(g->cur_fn_val, "NoAsyncPanic");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "NoAsyncOk");
LLVMBuildCondBr(g->builder, ok_val, ok_block, bad_block);
// The async function suspended, but this noasync call asserted it wouldn't.
LLVMPositionBuilderAtEnd(g->builder, bad_block);
gen_safety_crash(g, PanicMsgIdBadNoAsyncCall);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
}
ZigType *result_type = instruction->base.value.type;
ZigType *ptr_result_type = get_pointer_to_type(g, result_type, true);
return gen_await_early_return(g, &instruction->base, frame_result_loc,