Auto merge of rust-lang#128352 - Oneirical:daLTOnist-vision, r=<try>

Migrate `cross-lang-lto` `run-make` test to rmake

Part of rust-lang#121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).

Please try:

try-job: x86_64-msvc
try-job: i686-mingw
try-job: x86_64-mingw
try-job: armhf-gnu
try-job: test-various
try-job: aarch64-apple
try-job: x86_64-gnu-llvm-18

src/tools/run-make-support/src/external_deps/llvm.rs

@@ -36,6 +36,12 @@ pub fn llvm_ar() -> LlvmAr {
     LlvmAr::new()
 }
 
+/// Construct a new `llvm-bcanalyzer` invocation. This assumes that `llvm-bcanalyzer` is available
+/// at `$LLVM_BIN_DIR/llvm-bcanalyzer`.
+pub fn llvm_bcanalyzer() -> LlvmBcanalyzer {
+    LlvmBcanalyzer::new()
+}
+
 /// A `llvm-readobj` invocation builder.
 #[derive(Debug)]
 #[must_use]
@@ -71,11 +77,19 @@ pub struct LlvmAr {
     cmd: Command,
 }
 
+/// A `llvm-bcanalyzer` invocation builder.
+#[derive(Debug)]
+#[must_use]
+pub struct LlvmBcanalyzer {
+    cmd: Command,
+}
+
 crate::macros::impl_common_helpers!(LlvmReadobj);
 crate::macros::impl_common_helpers!(LlvmProfdata);
 crate::macros::impl_common_helpers!(LlvmFilecheck);
 crate::macros::impl_common_helpers!(LlvmObjdump);
 crate::macros::impl_common_helpers!(LlvmAr);
+crate::macros::impl_common_helpers!(LlvmBcanalyzer);
 
 /// Generate the path to the bin directory of LLVM.
 #[must_use]
@@ -244,3 +258,19 @@ impl LlvmAr {
         self
     }
 }
+
+impl LlvmBcanalyzer {
+    /// Construct a new `llvm-bcanalyzer` invocation. This assumes that `llvm-bcanalyzer` is available
+    /// at `$LLVM_BIN_DIR/llvm-bcanalyzer`.
+    pub fn new() -> Self {
+        let llvm_bcanalyzer = llvm_bin_dir().join("llvm-bcanalyzer");
+        let cmd = Command::new(llvm_bcanalyzer);
+        Self { cmd }
+    }
+
+    /// Provide an input file.
+    pub fn input<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
+        self.cmd.arg(path.as_ref());
+        self
+    }
+}

src/tools/run-make-support/src/lib.rs

@@ -48,8 +48,8 @@ pub use cc::{cc, cxx, extra_c_flags, extra_cxx_flags, Cc};
 pub use clang::{clang, Clang};
 pub use htmldocck::htmldocck;
 pub use llvm::{
-    llvm_ar, llvm_filecheck, llvm_objdump, llvm_profdata, llvm_readobj, LlvmAr, LlvmFilecheck,
-    LlvmObjdump, LlvmProfdata, LlvmReadobj,
+    llvm_ar, llvm_bcanalyzer, llvm_filecheck, llvm_objdump, llvm_profdata, llvm_readobj, LlvmAr,
+    LlvmBcanalyzer, LlvmFilecheck, LlvmObjdump, LlvmProfdata, LlvmReadobj,
 };
 pub use python::python_command;
 pub use rustc::{aux_build, bare_rustc, rustc, Rustc};

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -4,7 +4,6 @@ run-make/cdylib-dylib-linkage/Makefile
 run-make/cross-lang-lto-clang/Makefile
 run-make/cross-lang-lto-pgo-smoketest/Makefile
 run-make/cross-lang-lto-upstream-rlibs/Makefile
-run-make/cross-lang-lto/Makefile
 run-make/dep-info-doesnt-run-much/Makefile
 run-make/dep-info-spaces/Makefile
 run-make/dep-info/Makefile

tests/run-make/cross-lang-lto/rmake.rs

@@ -0,0 +1,112 @@
+// This test checks that the object files we generate are actually
+// LLVM bitcode files (as used by linker LTO plugins) when compiling with
+// -Clinker-plugin-lto.
+// See https://github.com/rust-lang/rust/pull/50000
+
+//FIXME(Oneirical): try it on windows
+
+#![feature(path_file_prefix)]
+
+use std::path::PathBuf;
+
+use run_make_support::{
+    cwd, has_extension, has_prefix, llvm_ar, llvm_bcanalyzer, path, rfs, rust_lib_name, rustc,
+    shallow_find_files, static_lib_name,
+};
+
+fn main() {
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("staticlib"),
+        output: path(static_lib_name("liblib")),
+        lto: None,
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("staticlib"),
+        output: path(static_lib_name("liblib-fat-lto")),
+        lto: Some("fat"),
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("staticlib"),
+        output: path(static_lib_name("liblib-thin-lto")),
+        lto: Some("thin"),
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("rlib"),
+        output: path(rust_lib_name("liblib")),
+        lto: None,
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("cdylib"),
+        output: path("cdylib.o"),
+        lto: None,
+        emit_obj: true,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("dylib"),
+        output: path("rdylib.o"),
+        lto: None,
+        emit_obj: true,
+    });
+    check_bitcode(LibBuild {
+        source: path("main.rs"),
+        crate_type: None,
+        output: path("exe.o"),
+        lto: None,
+        emit_obj: true,
+    });
+}
+
+#[track_caller]
+fn check_bitcode(instructions: LibBuild) {
+    let mut rustc = rustc();
+    rustc
+        .input(instructions.source)
+        .output(instructions.output.clone())
+        .opt_level("2")
+        .codegen_units(1)
+        .arg("-Clinker-plugin-lto");
+    if instructions.emit_obj {
+        rustc.emit("obj");
+    }
+    if let Some(crate_type) = instructions.crate_type {
+        rustc.crate_type(crate_type);
+    }
+    if let Some(lto) = instructions.lto {
+        rustc.arg(format!("-Clto={lto}"));
+    }
+    rustc.run();
+
+    if instructions.output.clone().extension().unwrap().to_str().unwrap() != "o" {
+        // Remove all potential leftover object files, then turn the output into an object file.
+        for object in shallow_find_files(cwd(), |path| has_extension(path, "o")) {
+            rfs::remove_file(object);
+        }
+        llvm_ar().arg("x").arg(instructions.output.clone()).run();
+    }
+
+    for object in shallow_find_files(cwd(), |path| {
+        has_prefix(path, instructions.output.file_prefix().unwrap().to_str().unwrap())
+            && has_extension(path, "o")
+    }) {
+        // All generated object files should be LLVM bitcode files - this will fail otherwise.
+        llvm_bcanalyzer().input(object).run();
+    }
+}
+
+struct LibBuild {
+    source: PathBuf,
+    crate_type: Option<&'static str>,
+    output: PathBuf,
+    lto: Option<&'static str>,
+    emit_obj: bool,
+}