Rollup merge of #74888 - infinity0:ignore-endian-big, r=nikomatsakis

compiletest: ignore-endian-big, fixes #74829, fixes #74885

See discussion on #74829

I tested it on a Debian s390x machine, works well.

src/tools/compiletest/src/header.rs

@@ -827,6 +827,7 @@ impl Config {
             name == util::get_pointer_width(&self.target) ||    // pointer width
             name == self.stage_id.split('-').next().unwrap() || // stage
             (self.target != self.host && name == "cross-compile") ||
+            (name == "endian-big" && util::is_big_endian(&self.target)) ||
             (self.remote_test_client.is_some() && name == "remote") ||
             match self.compare_mode {
                 Some(CompareMode::Nll) => name == "compare-mode-nll",

src/tools/compiletest/src/util.rs

@@ -99,6 +99,20 @@ pub const MSAN_SUPPORTED_TARGETS: &'static [&'static str] =
 pub const TSAN_SUPPORTED_TARGETS: &'static [&'static str] =
     &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
 
+const BIG_ENDIAN: &'static [&'static str] = &[
+    "armebv7r",
+    "mips",
+    "mips64",
+    "mipsisa32r6",
+    "mipsisa64r6",
+    "powerpc",
+    "powerpc64",
+    "s390x",
+    "sparc",
+    "sparc64",
+    "sparcv9",
+];
+
 pub fn matches_os(triple: &str, name: &str) -> bool {
     // For the wasm32 bare target we ignore anything also ignored on emscripten
     // and then we also recognize `wasm32-bare` as the os for the target
@@ -125,6 +139,12 @@ pub fn get_arch(triple: &str) -> &'static str {
     panic!("Cannot determine Architecture from triple");
 }
 
+/// Determine the endianness from `triple`
+pub fn is_big_endian(triple: &str) -> bool {
+    let triple_arch = triple.split('-').next().unwrap();
+    BIG_ENDIAN.contains(&triple_arch)
+}
+
 pub fn matches_env(triple: &str, name: &str) -> bool {
     if let Some(env) = triple.split('-').nth(3) { env.starts_with(name) } else { false }
 }