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//! Regression test for <https://github.com/rust-lang/rust/issues/135332>.
//!
//! We can't simply drop debuginfo location spans when LLVM's location discriminator value limit is
//! reached. Otherwise, with `-Z verify-llvm-ir` and fat LTO, LLVM will report a broken module for
//!
//! ```text
//! inlinable function call in a function with debug info must have a !dbg location
//! ```
//@ ignore-cross-compile
//@ needs-dynamic-linking
//@ only-nightly (requires unstable rustc flag)
#![deny(warnings)]
use run_make_support::{dynamic_lib_name, rfs, rust_lib_name, rustc};
// Synthesize a function that will have a large (`n`) number of functions
// MIR-inlined into it. When combined with a proc-macro, all of these inline
// callsites will have the same span, forcing rustc to use the DWARF
// discriminator to distinguish between them. LLVM's capacity to store that
// discriminator is not infinite (currently it allocates 12 bits for a
// maximum value of 4096) so if this function gets big enough rustc's error
// handling path will be exercised.
fn generate_program(n: u32) -> String {
let mut program = String::from("pub type BigType = Vec<Vec<String>>;\n\n");
program.push_str("pub fn big_function() -> BigType {\n");
program.push_str(" vec![\n");
for i in 1..=n {
program.push_str(&format!("vec![\"string{}\".to_owned()],\n", i));
}
program.push_str(" ]\n");
program.push_str("}\n");
program
}
fn main() {
// The reported threshold is around 1366 (4096/3), but let's bump it to
// around 1500 to be less sensitive.
rfs::write("generated.rs", generate_program(1500));
rustc()
.input("proc.rs")
.crate_type("proc-macro")
.edition("2021")
.arg("-Cdebuginfo=line-tables-only")
.run();
rustc()
.extern_("proc", dynamic_lib_name("proc"))
.input("other.rs")
.crate_type("rlib")
.edition("2021")
.opt_level("3")
.arg("-Cdebuginfo=line-tables-only")
.run();
rustc()
.extern_("other", rust_lib_name("other"))
.input("main.rs")
.edition("2021")
.opt_level("3")
.arg("-Cdebuginfo=line-tables-only")
.arg("-Clto=fat")
.arg("-Zverify-llvm-ir")
.run();
}
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