5 files changed, 42 insertions, 6 deletions
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index 230e11f274e..68f319ade1e 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -164,7 +164,8 @@ pub fn target_machine_factory(
 
     let code_model = to_llvm_code_model(sess.code_model());
 
-    let features = attributes::llvm_target_features(sess).collect::<Vec<_>>();
+    let mut features = llvm_util::handle_native_features(sess);
+    features.extend(attributes::llvm_target_features(sess).map(|s| s.to_owned()));
     let mut singlethread = sess.target.singlethread;
 
     // On the wasm target once the `atomics` feature is enabled that means that
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
index 72ba5bbd5f2..444a9d4ba04 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
@@ -292,7 +292,7 @@ fn add_unreachable_coverage<'tcx>(
         if let Some(non_codegenned_file_name) = tcx.covered_file_name(non_codegenned_def_id) {
             let def_ids = unreachable_def_ids_by_file
                 .entry(*non_codegenned_file_name)
-                .or_insert_with(|| Vec::new());
+                .or_insert_with(Vec::new);
             def_ids.push(non_codegenned_def_id);
         }
     }
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 707aaa2b53f..e359d9f8c9c 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1708,6 +1708,10 @@ extern "C" {
         PM: &PassManager<'_>,
     );
 
+    pub fn LLVMGetHostCPUFeatures() -> *mut c_char;
+
+    pub fn LLVMDisposeMessage(message: *mut c_char);
+
     // Stuff that's in llvm-wrapper/ because it's not upstream yet.
 
     /// Opens an object file.
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index a3139ce5a34..a9d57ea8b8a 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -8,7 +8,7 @@ use rustc_session::config::PrintRequest;
 use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::{MergeFunctions, PanicStrategy};
-use std::ffi::CString;
+use std::ffi::{CStr, CString};
 
 use std::slice;
 use std::str;
@@ -221,6 +221,37 @@ pub fn target_cpu(sess: &Session) -> &str {
     handle_native(name)
 }
 
+pub fn handle_native_features(sess: &Session) -> Vec<String> {
+    match sess.opts.cg.target_cpu {
+        Some(ref s) => {
+            if s != "native" {
+                return vec![];
+            }
+
+            let features_string = unsafe {
+                let ptr = llvm::LLVMGetHostCPUFeatures();
+                let features_string = if !ptr.is_null() {
+                    CStr::from_ptr(ptr)
+                        .to_str()
+                        .unwrap_or_else(|e| {
+                            bug!("LLVM returned a non-utf8 features string: {}", e);
+                        })
+                        .to_owned()
+                } else {
+                    bug!("could not allocate host CPU features, LLVM returned a `null` string");
+                };
+
+                llvm::LLVMDisposeMessage(ptr);
+
+                features_string
+            };
+
+            features_string.split(",").map(|s| s.to_owned()).collect()
+        }
+        None => vec![],
+    }
+}
+
 pub fn tune_cpu(sess: &Session) -> Option<&str> {
     match sess.opts.debugging_opts.tune_cpu {
         Some(ref s) => Some(handle_native(&**s)),
diff --git a/compiler/rustc_codegen_llvm/src/va_arg.rs b/compiler/rustc_codegen_llvm/src/va_arg.rs
index 3fc56eecdd0..07fde27b5a3 100644
--- a/compiler/rustc_codegen_llvm/src/va_arg.rs
+++ b/compiler/rustc_codegen_llvm/src/va_arg.rs
@@ -9,7 +9,7 @@ use rustc_codegen_ssa::{
 };
 use rustc_middle::ty::layout::HasTyCtxt;
 use rustc_middle::ty::Ty;
-use rustc_target::abi::{Align, HasDataLayout, LayoutOf, Size};
+use rustc_target::abi::{Align, Endian, HasDataLayout, LayoutOf, Size};
 
 fn round_pointer_up_to_alignment(
     bx: &mut Builder<'a, 'll, 'tcx>,
@@ -52,7 +52,7 @@ fn emit_direct_ptr_va_arg(
     let next = bx.inbounds_gep(addr, &[full_direct_size]);
     bx.store(next, va_list_addr, bx.tcx().data_layout.pointer_align.abi);
 
-    if size.bytes() < slot_size.bytes() && &*bx.tcx().sess.target.endian == "big" {
+    if size.bytes() < slot_size.bytes() && bx.tcx().sess.target.endian == Endian::Big {
         let adjusted_size = bx.cx().const_i32((slot_size.bytes() - size.bytes()) as i32);
         let adjusted = bx.inbounds_gep(addr, &[adjusted_size]);
         (bx.bitcast(adjusted, bx.cx().type_ptr_to(llty)), addr_align)
@@ -105,7 +105,7 @@ fn emit_aapcs_va_arg(
     let mut end = bx.build_sibling_block("va_arg.end");
     let zero = bx.const_i32(0);
     let offset_align = Align::from_bytes(4).unwrap();
-    assert!(&*bx.tcx().sess.target.endian == "little");
+    assert_eq!(bx.tcx().sess.target.endian, Endian::Little);
 
     let gr_type = target_ty.is_any_ptr() || target_ty.is_integral();
     let (reg_off, reg_top_index, slot_size) = if gr_type {