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SE-0281 was accepted with the modification that the main function should
be allowed to be throwing. Here support for enabling that is added.
Support is implemented in two steps:
(1) The $main wrapper function is modified to be throwing
static func $main() throws {
return try main()
}
whenever the main function is throwing (it remains non-throwing when
$main is not throwing).
(2) The @main entry point is modified to be
sil [ossa] @main : $@convention(c) (Int32, UnsafeMutablePointer<Optional<UnsafeMutablePointer<Int8>>>) -> Int32 {
entry(%argc : $Int32, %argv : $UnsafeMutablePointer<Optional<UnsafeMutablePointer<Int8>>>):
%the_main_type = metatype $@thin TheMainType.Type
%the_main_func = function_ref @`TheMainType.main()` : $@convention(method) (@thin TheMainType.Type) -> @error Error
try_apply %the_main_func(%the_main_type) : $@convention(method) (@thin TheMainType.Type) -> @error Error, normal success, error failure
success(%_ : $()):
%success_code_builtin_int32 = integer_literal $Builtin.Int32, 0
br bb1(%success_code_builtin_int32 : $Builtin.Int32)
failure(%error : @owned $Error):
%_ = builtin "errorInMain"(%error : $Error) : $()
end_lifetime %error : $Error
%error_code_builtin_int32 = integer_literal $Builtin.Int32, 1
br bb1(%error_code_builtin_int32 : $Builtin.Int32)
exit(%code_builtin_int32 : $Builtin.Int32):
%code = struct $Int32 (%code_builtin_int32 : $Builtin.Int32)
return %code : $Int32
}
whenever the main function is throwing (and consequently $main also is).
In the non-throwing case, (a) the try_apply instruction is replaced with an
apply instruction, (b) the body of the success block is appended to the
entry block, and (c) the success and failure blocks are removed.
9 lines
210 B
Swift
9 lines
210 B
Swift
// RUN: %target-swift-frontend -typecheck -parse-as-library -verify %s
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@main // expected-error{{'MyBase' is annotated with @main and must provide a main static function}}
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class MyBase {
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func main() {
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}
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}
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