src/test/incremental/thinlto/cgu_invalidated_when_import_added.rs

   1 // revisions: cfail1 cfail2
   2 // compile-flags: -O -Zhuman-readable-cgu-names -Cllvm-args=-import-instr-limit=10
   3 // build-pass
   4
   5 // rust-lang/rust#59535:
   6 //
   7 // This is analogous to cgu_invalidated_when_import_removed.rs, but it covers
   8 // the other direction:
   9 //
  10 // We start with a call-graph like `[A] -> [B -> D] [C]` (where the letters are
  11 // functions and the modules are enclosed in `[]`), and add a new call `D <- C`,
  12 // yielding the new call-graph: `[A] -> [B -> D] <- [C]`
  13 //
  14 // The effect of this is that the compiler previously classfied `D` as internal
  15 // and the import-set of `[A]` to be just `B`. But after adding the `D <- C` call,
  16 // `D` is no longer classified as internal, and the import-set of `[A]` becomes
  17 // both `B` and `D`.
  18 //
  19 // We check this case because an early proposed pull request included an
  20 // assertion that the import-sets monotonically decreased over time, a claim
  21 // which this test case proves to be false.
  22
  23 fn main() {
  24     foo::foo();
  25     bar::baz();
  26 }
  27
  28 mod foo {
  29
  30     // In cfail1, ThinLTO decides that foo() does not get inlined into main, and
  31     // instead bar() gets inlined into foo().
  32     // In cfail2, foo() gets inlined into main.
  33     pub fn foo(){
  34         bar()
  35     }
  36
  37     // This function needs to be big so that it does not get inlined by ThinLTO
  38     // but *does* get inlined into foo() when it is declared `internal` in
  39     // cfail1 (alone).
  40     pub fn bar(){
  41         println!("quux1");
  42         println!("quux2");
  43         println!("quux3");
  44         println!("quux4");
  45         println!("quux5");
  46         println!("quux6");
  47         println!("quux7");
  48         println!("quux8");
  49         println!("quux9");
  50     }
  51 }
  52
  53 mod bar {
  54
  55     #[inline(never)]
  56     pub fn baz() {
  57         #[cfg(cfail2)]
  58         {
  59             crate::foo::bar();
  60         }
  61     }
  62 }