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//! Test that the compiler can handle code bases with a high number of closures.
//! This is particularly important for the MinGW toolchain which has a limit of
//! 2^15 weak symbols per binary. This test creates 2^12 closures (256 functions
//! with 16 closures each) to check the compiler handles this correctly.
//!
//! Regression test for <https://github.com/rust-lang/rust/issues/34793>.
//! See also <https://github.com/rust-lang/rust/pull/34830>.
//@ run-pass
// Make sure we don't optimize anything away:
//@ compile-flags: -C no-prepopulate-passes -Cpasses=name-anon-globals
/// Macro for exponential expansion - creates 2^n copies of the given macro call
macro_rules! go_bacterial {
($mac:ident) => ($mac!());
($mac:ident 1 $($t:tt)*) => (
go_bacterial!($mac $($t)*);
go_bacterial!($mac $($t)*);
)
}
/// Creates and immediately calls a closure
macro_rules! create_closure {
() => {
(move || {})()
};
}
/// Creates a function containing 16 closures (2^4)
macro_rules! create_function_with_closures {
() => {
{
fn function_with_closures() {
// Create 16 closures using exponential expansion: 2^4 = 16
go_bacterial!(create_closure 1 1 1 1);
}
let _ = function_with_closures();
}
}
}
fn main() {
// Create 2^8 = 256 functions, each containing 16 closures,
// resulting in 2^12 = 4096 closures total.
go_bacterial!(create_function_with_closures 1 1 1 1 1 1 1 1);
}
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