Rollup merge of #128221 - calebzulawski:implied-target-features, r=Amanieu

Add implied target features to target_feature attribute

See [zulip](https://rust-lang.zulipchat.com/#narrow/stream/208962-t-libs.2Fstdarch/topic/Why.20would.20target-feature.20include.20implied.20features.3F) for some context.  Adds implied target features, e.g. `#[target_feature(enable = "avx2")]` acts like `#[target_feature(enable = "avx2,avx,sse4.2,sse4.1...")]`.  Fixes #128125, fixes #128426

The implied feature sets are taken from [the rust reference](https://doc.rust-lang.org/reference/attributes/codegen.html?highlight=target-fea#x86-or-x86_64), there are certainly more features and targets to add.

Please feel free to reassign this to whoever should review it.

r? ``@Amanieu``

Author: matthiaskrgr

compiler/rustc_codegen_gcc/src/attributes.rs

@@ -75,7 +75,7 @@ pub fn from_fn_attrs<'gcc, 'tcx>(
     let function_features = codegen_fn_attrs
         .target_features
         .iter()
-        .map(|features| features.as_str())
+        .map(|features| features.name.as_str())
         .collect::<Vec<&str>>();
 
     if let Some(features) = check_tied_features(

compiler/rustc_codegen_gcc/src/gcc_util.rs

@@ -65,8 +65,8 @@ pub(crate) fn global_gcc_features(sess: &Session, diagnostics: bool) -> Vec<Stri
 
             let feature = backend_feature_name(s)?;
             // Warn against use of GCC specific feature names on the CLI.
-            if diagnostics && !supported_features.iter().any(|&(v, _)| v == feature) {
-                let rust_feature = supported_features.iter().find_map(|&(rust_feature, _)| {
+            if diagnostics && !supported_features.iter().any(|&(v, _, _)| v == feature) {
+                let rust_feature = supported_features.iter().find_map(|&(rust_feature, _, _)| {
                     let gcc_features = to_gcc_features(sess, rust_feature);
                     if gcc_features.contains(&feature) && !gcc_features.contains(&rust_feature) {
                         Some(rust_feature)

compiler/rustc_codegen_gcc/src/lib.rs

@@ -486,7 +486,7 @@ pub fn target_features(
     sess.target
         .supported_target_features()
         .iter()
-        .filter_map(|&(feature, gate)| {
+        .filter_map(|&(feature, gate, _)| {
             if sess.is_nightly_build() || allow_unstable || gate.is_stable() {
                 Some(feature)
             } else {

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -496,7 +496,7 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     to_add.extend(tune_cpu_attr(cx));
 
     let function_features =
-        codegen_fn_attrs.target_features.iter().map(|f| f.as_str()).collect::<Vec<&str>>();
+        codegen_fn_attrs.target_features.iter().map(|f| f.name.as_str()).collect::<Vec<&str>>();
 
     if let Some(f) = llvm_util::check_tied_features(
         cx.tcx.sess,

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -95,11 +95,14 @@ pub fn write_output_file<'ll>(
     }
 }
 
-pub fn create_informational_target_machine(sess: &Session) -> OwnedTargetMachine {
+pub fn create_informational_target_machine(
+    sess: &Session,
+    only_base_features: bool,
+) -> OwnedTargetMachine {
     let config = TargetMachineFactoryConfig { split_dwarf_file: None, output_obj_file: None };
     // Can't use query system here quite yet because this function is invoked before the query
     // system/tcx is set up.
-    let features = llvm_util::global_llvm_features(sess, false);
+    let features = llvm_util::global_llvm_features(sess, false, only_base_features);
     target_machine_factory(sess, config::OptLevel::No, &features)(config)
         .unwrap_or_else(|err| llvm_err(sess.dcx(), err).raise())
 }

compiler/rustc_codegen_llvm/src/context.rs

@@ -149,7 +149,7 @@ pub unsafe fn create_module<'ll>(
 
     // Ensure the data-layout values hardcoded remain the defaults.
     {
-        let tm = crate::back::write::create_informational_target_machine(tcx.sess);
+        let tm = crate::back::write::create_informational_target_machine(tcx.sess, false);
         unsafe {
             llvm::LLVMRustSetDataLayoutFromTargetMachine(llmod, &tm);
         }

compiler/rustc_codegen_llvm/src/lib.rs

@@ -269,7 +269,7 @@ impl CodegenBackend for LlvmCodegenBackend {
 
     fn provide(&self, providers: &mut Providers) {
         providers.global_backend_features =
-            |tcx, ()| llvm_util::global_llvm_features(tcx.sess, true)
+            |tcx, ()| llvm_util::global_llvm_features(tcx.sess, true, false)
     }
 
     fn print(&self, req: &PrintRequest, out: &mut String, sess: &Session) {
@@ -434,7 +434,7 @@ impl ModuleLlvm {
             ModuleLlvm {
                 llmod_raw,
                 llcx,
-                tm: ManuallyDrop::new(create_informational_target_machine(tcx.sess)),
+                tm: ManuallyDrop::new(create_informational_target_machine(tcx.sess, false)),
             }
         }
     }