Rollup merge of #135174 - xingxue-ibm:reproducible-build-aix, r=jieyouxu

[AIX] Port test case run-make/reproducible-build

The test case `run-make/reproducible-build` verifies that two identical invocations of the compiler produce the same output by comparing the linker arguments, resulting binaries, and other artifacts. However, the AIX linker command includes an argument that specifies the file containing exported symbols, with a file path that contains a randomly generated substring to prevent collisions between different linking processes. Additionally, the AIX XCOFF file header includes a 4-byte timestamp. This PR replaces the random substring with a placeholder and nullifies the timestamp field in the XCOFF files for the comparisons.

Author: GuillaumeGomez

Diff for: tests/run-make/reproducible-build/rmake.rs

@@ -21,7 +21,7 @@
 // Tracking Issue: https://github.com/rust-lang/rust/issues/129080
 
 use run_make_support::{
-    bin_name, cwd, diff, is_darwin, is_windows, rfs, run_in_tmpdir, rust_lib_name, rustc,
+    bin_name, cwd, diff, is_darwin, is_windows, regex, rfs, run_in_tmpdir, rust_lib_name, rustc,
 };
 
 fn main() {
@@ -117,7 +117,34 @@ fn smoke_test(flag: Option<SmokeFlag>) {
             .input("reproducible-build.rs")
             .linker(&cwd().join(bin_name("linker")).display().to_string())
             .run();
-        diff().actual_file("linker-arguments1").expected_file("linker-arguments2").run();
+
+        #[cfg(not(target_os = "aix"))]
+        {
+            diff().actual_file("linker-arguments1").expected_file("linker-arguments2").run();
+        }
+        #[cfg(target_os = "aix")]
+        {
+            // The AIX link command includes an additional argument
+            // that specifies the file containing exported symbols, e.g.,
+            // -bE:/tmp/rustcO6hxkY/list.exp. In this example, the part of the
+            // directory name "rustcO6hxkY" is randomly generated to ensure that
+            // different linking processes do not collide. For the purpose
+            // of comparing link arguments, the randomly generated part is
+            // replaced with a placeholder.
+            let content1 =
+                std::fs::read_to_string("linker-arguments1").expect("Failed to read file");
+            let content2 =
+                std::fs::read_to_string("linker-arguments2").expect("Failed to read file");
+
+            // Define the regex for the directory name containing the random substring.
+            let re = regex::Regex::new(r"rustc[a-zA-Z0-9]{6}/list\.exp").expect("Invalid regex");
+
+            // Compare link commands with random strings replaced by placeholders.
+            assert!(
+                re.replace_all(&content1, "rustcXXXXXX/list.exp").to_string()
+                    == re.replace_all(&content2, "rustcXXXXXX/list.exp").to_string()
+            );
+        }
     });
 }
 
@@ -207,7 +234,21 @@ fn diff_dir_test(crate_type: CrateType, remap_type: RemapType) {
         std::env::set_current_dir(&base_dir).unwrap();
         match crate_type {
             CrateType::Bin => {
-                assert!(rfs::read(bin_name("reproducible-build")) == rfs::read(bin_name("foo")));
+                #[cfg(not(target_os = "aix"))]
+                {
+                    assert!(
+                        rfs::read(bin_name("reproducible-build")) == rfs::read(bin_name("foo"))
+                    );
+                }
+                #[cfg(target_os = "aix")]
+                {
+                    // At the 4th-byte offset, the AIX XCOFF file header defines a
+                    // 4-byte timestamp. Nullify the timestamp before performing a
+                    // binary comparison.
+                    let mut file1 = rfs::read(bin_name("reproducible-build"));
+                    let mut file2 = rfs::read(bin_name("foo"));
+                    assert!(file1[4..8].fill(0x00) == file2[4..8].fill(0x00));
+                };
             }
             CrateType::Rlib => {
                 assert!(