Auto merge of #131917 - jieyouxu:rmake-clang, r=Kobzol

Run the full stage 2 `run-make` test suite in `x86_64-gnu-debug`

Run the full `run-make` test suite in the `x86_64-gnu-debug` CI job. This is currently the *only* CI job where `//@ needs-force-clang-based-test` will be satisfied, so some `run-make` tests will literally never be run otherwise. Before this PR, the CI job only ran `run-make` tests which contains the substring `clang` in its test name, which is both (1) a footgun because it's very easy to forget and (2) it masks tests that would otherwise fail (even failing to compile) because the test is skipped if doesn't have a `clang` in its test name.

With the environment of `x86_64-gnu-debug`, two `run-make` tests failed before this PR:

1. `tests/run-make/issue-84395-lto-embed-bitcode/rmake.rs`: this was broken for a long time because `objcopy` in llvm bin tools was renamed to `llvm-objcopy`. This test was converted into a rmake.rs test, rather straight forward.
2. `tests/run-make/cross-lang-lto-riscv-abi/rmake.rs`: this was broken for a long time and never worked. The old version inspected human-readable output of `llvm-readobj --file-header` looking for substring `EF_RISCV_FLOAT_ABI_DOUBLE`, but the human-readable output will only contain something like `Flags: 0x5, RVC, double-float ABI`, hence it will never match. This test was fixed by instead using the `object` crate to actually decode the ELF headers looking for the specific `e_flags` based on reading the RISCV ELF psABI docs.

This PR is best reviewed commit-by-commit, two commits setup the support library for functionality and two commits are for each of the failing `run-make` tests.

I had to bump the `x86_64-gnu-debug` job to be ran with a runner with larger disk space.

Part of #132034.

try-job: x86_64-gnu-debug

3 files changed, 88 insertions, 37 deletions

diff --git a/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs b/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs
index 92573353a74..e595dbea94d 100644
--- a/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs
+++ b/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs
@@ -1,21 +1,20 @@
-//! Make sure that cross-language LTO works on riscv targets,
-//! which requires extra `target-abi` metadata to be emitted.
+//! Make sure that cross-language LTO works on riscv targets, which requires extra `target-abi`
+//! metadata to be emitted.
 //@ needs-force-clang-based-tests
-//@ needs-llvm-components riscv
+//@ needs-llvm-components: riscv
 
-//@ needs-force-clang-based-tests
-// FIXME(#126180): This test can only run on `x86_64-gnu-debug`, because that CI job sets
-// RUSTBUILD_FORCE_CLANG_BASED_TESTS and only runs tests which contain "clang" in their
-// name.
-// However, this test does not run at all as its name does not contain "clang".
-
-use std::path::PathBuf;
-use std::process::{Command, Output};
-use std::{env, str};
+// ignore-tidy-linelength
 
-use run_make_support::{bin_name, clang, llvm_readobj, rustc};
+use object::elf;
+use object::read::elf as readelf;
+use run_make_support::{bin_name, clang, object, rfs, rustc};
 
-fn check_target(target: &str, clang_target: &str, carch: &str, is_double_float: bool) {
+fn check_target<H: readelf::FileHeader<Endian = object::Endianness>>(
+    target: &str,
+    clang_target: &str,
+    carch: &str,
+    is_double_float: bool,
+) {
     eprintln!("Checking target {target}");
     // Rust part
     rustc()
@@ -39,16 +38,55 @@ fn check_target(target: &str, clang_target: &str, carch: &str, is_double_float:
 
     // Check that the built binary has correct float abi
     let executable = bin_name("riscv-xlto");
-    let output = llvm_readobj().input(&executable).file_header().run();
-    let stdout = String::from_utf8_lossy(&output.stdout);
-    eprintln!("obj:\n{}", stdout);
-
-    assert!(!(is_double_float ^ stdout.contains("EF_RISCV_FLOAT_ABI_DOUBLE")));
+    let data = rfs::read(&executable);
+    let header = <H>::parse(&*data).unwrap();
+    let endian = match header.e_ident().data {
+        elf::ELFDATA2LSB => object::Endianness::Little,
+        elf::ELFDATA2MSB => object::Endianness::Big,
+        x => unreachable!("invalid e_ident data: {:#010b}", x),
+    };
+    // Check `(e_flags & EF_RISCV_FLOAT_ABI) == EF_RISCV_FLOAT_ABI_DOUBLE`.
+    //
+    // See
+    // <https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#elf-object-files>.
+    if is_double_float {
+        assert_eq!(
+            header.e_flags(endian) & elf::EF_RISCV_FLOAT_ABI,
+            elf::EF_RISCV_FLOAT_ABI_DOUBLE,
+            "expected {target} to use double ABI, but it did not"
+        );
+    } else {
+        assert_ne!(
+            header.e_flags(endian) & elf::EF_RISCV_FLOAT_ABI,
+            elf::EF_RISCV_FLOAT_ABI_DOUBLE,
+            "did not expected {target} to use double ABI"
+        );
+    }
 }
 
 fn main() {
-    check_target("riscv64gc-unknown-linux-gnu", "riscv64-linux-gnu", "rv64gc", true);
-    check_target("riscv64imac-unknown-none-elf", "riscv64-unknown-elf", "rv64imac", false);
-    check_target("riscv32imac-unknown-none-elf", "riscv32-unknown-elf", "rv32imac", false);
-    check_target("riscv32gc-unknown-linux-gnu", "riscv32-linux-gnu", "rv32gc", true);
+    check_target::<elf::FileHeader64<object::Endianness>>(
+        "riscv64gc-unknown-linux-gnu",
+        "riscv64-linux-gnu",
+        "rv64gc",
+        true,
+    );
+    check_target::<elf::FileHeader64<object::Endianness>>(
+        "riscv64imac-unknown-none-elf",
+        "riscv64-unknown-elf",
+        "rv64imac",
+        false,
+    );
+    check_target::<elf::FileHeader32<object::Endianness>>(
+        "riscv32imac-unknown-none-elf",
+        "riscv32-unknown-elf",
+        "rv32imac",
+        false,
+    );
+    check_target::<elf::FileHeader32<object::Endianness>>(
+        "riscv32gc-unknown-linux-gnu",
+        "riscv32-linux-gnu",
+        "rv32gc",
+        true,
+    );
 }
diff --git a/tests/run-make/issue-84395-lto-embed-bitcode/Makefile b/tests/run-make/issue-84395-lto-embed-bitcode/Makefile
deleted file mode 100644
index aabe90754a6..00000000000
--- a/tests/run-make/issue-84395-lto-embed-bitcode/Makefile
+++ /dev/null
@@ -1,14 +0,0 @@
-# needs-force-clang-based-tests
-
-# FIXME(#126180): This test doesn't actually run anywhere, because the only
-# CI job that sets RUSTBUILD_FORCE_CLANG_BASED_TESTS runs very few tests.
-
-# This test makes sure the embed bitcode in elf created with
-# lto-embed-bitcode=optimized is valid llvm BC module.
-
-include ../tools.mk
-
-all:
-	$(RUSTC) test.rs --target $(TARGET) -Clink-arg=-fuse-ld=lld -Clinker-plugin-lto -Clinker=$(CLANG) -Clink-arg=-Wl,--plugin-opt=-lto-embed-bitcode=optimized -Zemit-thin-lto=no
-	$(LLVM_BIN_DIR)/objcopy --dump-section .llvmbc=$(TMPDIR)/test.bc $(TMPDIR)/test
-	$(LLVM_BIN_DIR)/llvm-dis $(TMPDIR)/test.bc
diff --git a/tests/run-make/issue-84395-lto-embed-bitcode/rmake.rs b/tests/run-make/issue-84395-lto-embed-bitcode/rmake.rs
new file mode 100644
index 00000000000..450d8a9f099
--- /dev/null
+++ b/tests/run-make/issue-84395-lto-embed-bitcode/rmake.rs
@@ -0,0 +1,27 @@
+//! Smoke test to make sure the embed bitcode in elf created with
+//! `--plugin-opt=-lto-embed-bitcode=optimized` is valid llvm BC module.
+//!
+//! See <https://github.com/rust-lang/rust/issues/84395> where passing
+//! `-lto-embed-bitcode=optimized` to lld when linking rust code via `linker-plugin-lto` doesn't
+//! produce the expected result.
+//!
+//! See PR <https://github.com/rust-lang/rust/pull/98162> which initially introduced this test.
+
+//@ needs-force-clang-based-tests
+
+use run_make_support::{env_var, llvm_dis, llvm_objcopy, rustc};
+
+fn main() {
+    rustc()
+        .input("test.rs")
+        .arg("-Clink-arg=-fuse-ld=lld")
+        .arg("-Clinker-plugin-lto")
+        .arg(format!("-Clinker={}", env_var("CLANG")))
+        .arg("-Clink-arg=-Wl,--plugin-opt=-lto-embed-bitcode=optimized")
+        .arg("-Zemit-thin-lto=no")
+        .run();
+
+    llvm_objcopy().dump_section(".llvmbc", "test.bc").arg("test").run();
+
+    llvm_dis().arg("test.bc").run();
+}