rewrite pgo-use to rmake

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -110,7 +110,6 @@ run-make/pdb-buildinfo-cl-cmd/Makefile
 run-make/pgo-gen-lto/Makefile
 run-make/pgo-gen-no-imp-symbols/Makefile
 run-make/pgo-indirect-call-promotion/Makefile
-run-make/pgo-use/Makefile
 run-make/pointer-auth-link-with-c/Makefile
 run-make/print-calling-conventions/Makefile
 run-make/print-target-list/Makefile

tests/run-make/pgo-use/Makefile

@@ -0,0 +1,54 @@
+// This test makes sure that PGO profiling data leads to cold functions being
+// marked as `cold` and hot functions with `inlinehint`.
+// The test program contains an `if` where actual execution only ever takes the
+// `else` branch. Accordingly, we expect the function that is never called to
+// be marked as cold.
+// See https://github.com/rust-lang/rust/pull/60262
+
+//@ needs-profiler-support
+//@ ignore-cross-compile
+
+use run_make_support::{
+    cwd, find_files_by_prefix_and_extension, fs_wrapper, llvm_filecheck, llvm_profdata,
+    run_with_args, rustc,
+};
+
+fn main() {
+    // Compile the test program with instrumentation
+    // Disable the pre-inlining pass (i.e. a pass that does some inlining before
+    // it adds the profiling instrumentation). Disabling this pass leads to
+    // rather predictable IR which we need for this test to be stable.
+    rustc()
+        .opt_level("2")
+        .codegen_units(1)
+        .arg("-Cllvm-args=-disable-preinline")
+        .profile_generate(cwd())
+        .input("main.rs")
+        .run();
+    // Run it in order to generate some profiling data
+    run_with_args("main", &["some-argument"]);
+    // Postprocess the profiling data so it can be used by the compiler
+    llvm_profdata()
+        .merge()
+        .output("merged.profdata")
+        .input(find_files_by_prefix_and_extension(cwd(), "default", "profraw").get(0).unwrap())
+        .run();
+    // Compile the test program again, making use of the profiling data
+    rustc()
+        .opt_level("2")
+        .codegen_units(1)
+        .arg("-Cllvm-args=-disable-preinline")
+        .profile_use("merged.profdata")
+        .emit("llvm-ir")
+        .input("main.rs")
+        .run();
+    // Check that the generate IR contains some things that we expect
+    //
+    // We feed the file into LLVM FileCheck tool *in reverse* so that we see the
+    // line with the function name before the line with the function attributes.
+    // FileCheck only supports checking that something matches on the next line,
+    // but not if something matches on the previous line.
+    let mut bytes = fs_wrapper::read("interesting.ll");
+    bytes.reverse();
+    llvm_filecheck().patterns("filecheck-patterns.txt").stdin(bytes).run();
+}