handle uefi and test assembly versus regular functions

Author: folkertdev

compiler/rustc_codegen_ssa/src/mir/naked_asm.rs

@@ -8,7 +8,7 @@ use rustc_middle::ty::{Instance, Ty, TyCtxt, TypeVisitableExt};
 use rustc_middle::{bug, ty};
 use rustc_span::sym;
 use rustc_target::callconv::{ArgAbi, FnAbi, PassMode};
-use rustc_target::spec::{Arch, BinaryFormat, Env};
+use rustc_target::spec::{Arch, BinaryFormat, Env, Os};
 
 use crate::common;
 use crate::mir::AsmCodegenMethods;
@@ -268,6 +268,8 @@ fn prefix_and_suffix<'tcx>(
             // `.subsections_via_symbols` global directive. LLVM already enables this directive.
             if let Some(section) = &link_section {
                 writeln!(begin, ".pushsection {section},regular,pure_instructions").unwrap();
+            } else {
+                writeln!(begin, ".section __TEXT,__text,regular,pure_instructions").unwrap();
             }
             writeln!(begin, ".balign {align_bytes}").unwrap();
             write_linkage(&mut begin).unwrap();
@@ -313,7 +315,13 @@ fn prefix_and_suffix<'tcx>(
                     Env::Msvc => {
                         writeln!(begin, ".section .text,\"xr\",one_only,{asm_name}").unwrap();
                     }
-                    other => bug!("invalid coff env {other:?}"),
+                    Env::Unspecified => match &tcx.sess.target.options.os {
+                        Os::Uefi => {
+                            writeln!(begin, ".section .text,\"xr\",one_only,{asm_name}").unwrap();
+                        }
+                        _ => bug!("unexpected coff target {}", tcx.sess.target.llvm_target),
+                    },
+                    other => bug!("unexpected coff env {other:?}"),
                 }
             }
             write_linkage(&mut begin).unwrap();

tests/assembly-llvm/naked-functions/function-sections.rs

@@ -0,0 +1,97 @@
+//@ add-minicore
+//@ assembly-output: emit-asm
+//
+//@ revisions: linux-x86-gnu-fs-true linux-x86-gnu-fs-false
+//@[linux-x86-gnu-fs-true] compile-flags: --target x86_64-unknown-linux-gnu -Zfunction-sections=true
+//@[linux-x86-gnu-fs-true] needs-llvm-components: x86
+//@[linux-x86-gnu-fs-false] compile-flags: --target x86_64-unknown-linux-gnu -Zfunction-sections=false
+//@[linux-x86-gnu-fs-false] needs-llvm-components: x86
+//
+//@ revisions: macos-aarch64-fs-true macos-aarch64-fs-false
+//@[macos-aarch64-fs-true] compile-flags: --target aarch64-apple-darwin -Zfunction-sections=true
+//@[macos-aarch64-fs-true] needs-llvm-components: aarch64
+//@[macos-aarch64-fs-false] compile-flags: --target aarch64-apple-darwin -Zfunction-sections=false
+//@[macos-aarch64-fs-false] needs-llvm-components: aarch64
+//
+//@ revisions: windows-x86-gnu-fs-true windows-x86-gnu-fs-false
+//@[windows-x86-gnu-fs-true] compile-flags: --target x86_64-pc-windows-gnu -Zfunction-sections=true
+//@[windows-x86-gnu-fs-true] needs-llvm-components: x86
+//@[windows-x86-gnu-fs-false] compile-flags: --target x86_64-pc-windows-gnu -Zfunction-sections=false
+//@[windows-x86-gnu-fs-false] needs-llvm-components: x86
+//
+//@ revisions: windows-x86-msvc-fs-true windows-x86-msvc-fs-false
+//@[windows-x86-msvc-fs-true] compile-flags: --target x86_64-pc-windows-msvc -Zfunction-sections=true
+//@[windows-x86-msvc-fs-true] needs-llvm-components: x86
+//@[windows-x86-msvc-fs-false] compile-flags: --target x86_64-pc-windows-msvc -Zfunction-sections=false
+//@[windows-x86-msvc-fs-false] needs-llvm-components: x86
+//
+//@ revisions: x86-uefi-fs-true x86-uefi-fs-false
+//@[x86-uefi-fs-true] compile-flags: --target x86_64-unknown-uefi -Zfunction-sections=true
+//@[x86-uefi-fs-true] needs-llvm-components: x86
+//@[x86-uefi-fs-false] compile-flags: --target x86_64-unknown-uefi -Zfunction-sections=false
+//@[x86-uefi-fs-false] needs-llvm-components: x86
+
+#![crate_type = "lib"]
+#![feature(no_core)]
+#![no_core]
+
+// Tests that naked and non-naked functions emit the same directives when (not) using
+// -Zfunction-sections. This setting is ignored on macos, off by default on windows gnu,
+// and on by default in the remaining revisions tested here.
+
+extern crate minicore;
+use minicore::*;
+
+#[unsafe(naked)]
+#[unsafe(no_mangle)]
+extern "C" fn naked_ret() {
+    // linux-x86-gnu-fs-true: .section .text.naked_ret,"ax",@progbits
+    // linux-x86-gnu-fs-false: .text
+    //
+    // macos-aarch64-fs-true:  .section __TEXT,__text,regular,pure_instructions
+    // macos-aarch64-fs-false: .section __TEXT,__text,regular,pure_instructions
+    //
+    // NOTE: the regular function below adds `unique,0` at the end, but we have no way of generating
+    // the unique ID to use there, so don't emit that part.
+    //
+    // windows-x86-gnu-fs-true: .section .text$naked_ret,"xr",one_only,naked_ret
+    // windows-x86-msvc-fs-true: .section .text,"xr",one_only,naked_ret
+    // x86-uefi-fs-true: .section .text,"xr",one_only,naked_ret
+    //
+    // windows-x86-gnu-fs-false: .text
+    // windows-x86-msvc-fs-false: .text
+    // x86-uefi-fs-false: .text
+    //
+    // CHECK-LABEL: naked_ret:
+    naked_asm!("ret")
+}
+
+// Use a different section here so that `regular_ret` has to explicitly specify the section.
+#[link_section = cfg_select!(
+    target_os = "macos" => "__FOO,bar",
+    _ => ".bar",
+)]
+#[unsafe(no_mangle)]
+extern "C" fn omarker() -> i32 {
+    // CHECK-LABEL: omarker:
+    32
+}
+
+#[unsafe(no_mangle)]
+extern "C" fn regular_ret() {
+    // linux-x86-gnu-fs-true: .section .text.regular_ret,"ax",@progbits
+    // linux-x86-gnu-fs-false: .text
+    //
+    // macos-aarch64-fs-true:  .section __TEXT,__text,regular,pure_instructions
+    // macos-aarch64-fs-false: .section __TEXT,__text,regular,pure_instructions
+    //
+    // windows-x86-gnu-fs-true: .section .text$regular_ret,"xr",one_only,regular_ret,unique,0
+    // windows-x86-msvc-fs-true: .section .text,"xr",one_only,regular_ret,unique,0
+    // x86-uefi-fs-true: .section .text,"xr",one_only,regular_ret,unique,0
+    //
+    // windows-x86-gnu-fs-false: .text
+    // windows-x86-msvc-fs-false: .text
+    // x86-uefi-fs-false: .text
+    //
+    // CHECK-LABEL: regular_ret:
+}