Auto merge of #126534 - Rejyr:comment-section-migration, r=<try>

Migrate `run-make/comment-section` to `rmake.rs`

Part of #121876.

r? `@jieyouxu`

try-job: dist-aarch64-linux
try-job: dist-armhf-linux
try-job: x86_64-gnu-llvm-18
try-job: test-various
try-job: dist-various-1

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

@@ -2,8 +2,8 @@ use std::path::{Path, PathBuf};
 
 use crate::{env_var, Command};
 
-/// Construct a new `llvm-readobj` invocation. This assumes that `llvm-readobj` is available
-/// at `$LLVM_BIN_DIR/llvm-readobj`.
+/// Construct a new `llvm-readobj` invocation with the `GNU` output style.
+/// This assumes that `llvm-readobj` is available at `$LLVM_BIN_DIR/llvm-readobj`.
 pub fn llvm_readobj() -> LlvmReadobj {
     LlvmReadobj::new()
 }
@@ -53,12 +53,23 @@ pub fn llvm_bin_dir() -> PathBuf {
 }
 
 impl LlvmReadobj {
-    /// Construct a new `llvm-readobj` invocation. This assumes that `llvm-readobj` is available
-    /// at `$LLVM_BIN_DIR/llvm-readobj`.
+    /// Construct a new `llvm-readobj` invocation with the `GNU` output style.
+    /// This assumes that `llvm-readobj` is available at `$LLVM_BIN_DIR/llvm-readobj`.
     pub fn new() -> Self {
         let llvm_readobj = llvm_bin_dir().join("llvm-readobj");
         let cmd = Command::new(llvm_readobj);
-        Self { cmd }
+        let mut readobj = Self { cmd };
+        readobj.elf_output_style("GNU");
+        readobj
+    }
+
+    /// Specify the format of the ELF information.
+    ///
+    /// Valid options are `LLVM` (default), `GNU`, and `JSON`.
+    pub fn elf_output_style(&mut self, style: &str) -> &mut Self {
+        self.cmd.arg("--elf-output-style");
+        self.cmd.arg(style);
+        self
     }
 
     /// Provide an input file.
@@ -72,6 +83,13 @@ impl LlvmReadobj {
         self.cmd.arg("--file-header");
         self
     }
+
+    /// Specify the section to display.
+    pub fn section(&mut self, section: &str) -> &mut Self {
+        self.cmd.arg("--string-dump");
+        self.cmd.arg(section);
+        self
+    }
 }
 
 impl LlvmProfdata {

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -11,7 +11,6 @@ run-make/c-unwind-abi-catch-panic/Makefile
 run-make/cat-and-grep-sanity-check/Makefile
 run-make/cdylib-dylib-linkage/Makefile
 run-make/cdylib-fewer-symbols/Makefile
-run-make/comment-section/Makefile
 run-make/compiler-lookup-paths-2/Makefile
 run-make/compiler-lookup-paths/Makefile
 run-make/compiler-rt-works-on-mingw/Makefile

tests/run-make/comment-section/rmake.rs

@@ -0,0 +1,45 @@
+// Both GCC and Clang write by default a `.comment` section with compiler information.
+// Rustc received a similar .comment section, so this tests checks that this section
+// properly appears.
+// See https://github.com/rust-lang/rust/commit/74b8d324eb77a8f337b35dc68ac91b0c2c06debc
+
+//@ only-linux
+
+use std::path::PathBuf;
+
+use run_make_support::llvm_readobj;
+use run_make_support::rustc;
+use run_make_support::{cwd, env_var, read_dir, run_in_tmpdir};
+
+fn main() {
+    let target = env_var("TARGET");
+
+    rustc()
+        .arg("-")
+        .stdin("fn main() {}")
+        .emit("link,obj")
+        .arg("-Csave-temps")
+        .target(&target)
+        .run();
+
+    // Check linked output has a `.comment` section with the expected content.
+    llvm_readobj()
+        .section(".comment")
+        .input("rust_out")
+        .run()
+        .assert_stdout_contains("rustc version 1.");
+
+    // Check all object files (including temporary outputs) have a `.comment`
+    // section with the expected content.
+    read_dir(cwd(), |f| {
+        if !f.extension().is_some_and(|ext| ext == "o") {
+            return;
+        }
+
+        llvm_readobj()
+            .section(".comment")
+            .input(&f)
+            .run()
+            .assert_stdout_contains("rustc version 1.");
+    });
+}