mirror of https://github.com/rust-lang/rust
56 lines
2.4 KiB
Rust
56 lines
2.4 KiB
Rust
// This test makes sure that PGO profiling data leads to cold functions being
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// marked as `cold` and hot functions with `inlinehint`.
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// The test program contains an `if` where actual execution only ever takes the
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// `else` branch. Accordingly, we expect the function that is never called to
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// be marked as cold.
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// See https://github.com/rust-lang/rust/pull/60262
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//@ needs-profiler-support
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//@ ignore-cross-compile
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use run_make_support::{
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cwd, has_extension, has_prefix, llvm_filecheck, llvm_profdata, rfs, run_with_args, rustc,
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shallow_find_files,
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};
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fn main() {
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// Compile the test program with instrumentation
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// Disable the pre-inlining pass (i.e. a pass that does some inlining before
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// it adds the profiling instrumentation). Disabling this pass leads to
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// rather predictable IR which we need for this test to be stable.
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rustc()
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.opt_level("2")
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.codegen_units(1)
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.arg("-Cllvm-args=-disable-preinline")
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.profile_generate(cwd())
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.input("main.rs")
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.run();
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// Run it in order to generate some profiling data
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run_with_args("main", &["some-argument"]);
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// Postprocess the profiling data so it can be used by the compiler
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let profraw_files = shallow_find_files(cwd(), |path| {
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has_prefix(path, "default") && has_extension(path, "profraw")
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});
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let profraw_file = profraw_files.get(0).unwrap();
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llvm_profdata().merge().output("merged.profdata").input(profraw_file).run();
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// Compile the test program again, making use of the profiling data
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rustc()
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.opt_level("2")
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.codegen_units(1)
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.arg("-Cllvm-args=-disable-preinline")
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.profile_use("merged.profdata")
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.emit("llvm-ir")
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.input("main.rs")
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.run();
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// Check that the generate IR contains some things that we expect.
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// We feed the file into LLVM FileCheck tool *with its lines reversed* so that we see the
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// line with the function name before the line with the function attributes.
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// FileCheck only supports checking that something matches on the next line,
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// but not if something matches on the previous line.
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let ir = rfs::read_to_string("main.ll");
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let lines: Vec<_> = ir.lines().rev().collect();
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let mut reversed_ir = lines.join("\n");
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reversed_ir.push('\n');
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llvm_filecheck().patterns("filecheck-patterns.txt").stdin_buf(reversed_ir.as_bytes()).run();
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}
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