Rollup merge of #97633 - mkroening:object-osabi, r=petrochenkov

Session object: Set OS/ABI

Closes https://github.com/rust-lang/rust/issues/97535.

This depends on
* https://github.com/gimli-rs/object/pull/438

This adapts LLVM's behavior of [`MCELFObjectTargetWriter::getOSABI`](https://github.com/llvm/llvm-project/blob/8c8a2679a20f621994fa904bcfc68775e7345edc/llvm/include/llvm/MC/MCELFObjectWriter.h#L72-L86).

1 files changed, 14 insertions, 5 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/metadata.rs b/compiler/rustc_codegen_ssa/src/back/metadata.rs
index 6aa96f9f403..3dd607adee5 100644
--- a/compiler/rustc_codegen_ssa/src/back/metadata.rs
+++ b/compiler/rustc_codegen_ssa/src/back/metadata.rs
@@ -130,7 +130,7 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
     };
 
     let mut file = write::Object::new(binary_format, architecture, endianness);
-    match architecture {
+    let e_flags = match architecture {
         Architecture::Mips => {
             let arch = match sess.target.options.cpu.as_ref() {
                 "mips1" => elf::EF_MIPS_ARCH_1,
@@ -149,7 +149,7 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
             if sess.target.options.cpu.contains("r6") {
                 e_flags |= elf::EF_MIPS_NAN2008;
             }
-            file.flags = FileFlags::Elf { e_flags };
+            e_flags
         }
         Architecture::Mips64 => {
             // copied from `mips64el-linux-gnuabi64-gcc foo.c -c`
@@ -160,17 +160,26 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
                 } else {
                     elf::EF_MIPS_ARCH_64R2
                 };
-            file.flags = FileFlags::Elf { e_flags };
+            e_flags
         }
         Architecture::Riscv64 if sess.target.options.features.contains("+d") => {
             // copied from `riscv64-linux-gnu-gcc foo.c -c`, note though
             // that the `+d` target feature represents whether the double
             // float abi is enabled.
             let e_flags = elf::EF_RISCV_RVC | elf::EF_RISCV_FLOAT_ABI_DOUBLE;
-            file.flags = FileFlags::Elf { e_flags };
+            e_flags
         }
-        _ => {}
+        _ => 0,
+    };
+    // adapted from LLVM's `MCELFObjectTargetWriter::getOSABI`
+    let os_abi = match sess.target.options.os.as_ref() {
+        "hermit" => elf::ELFOSABI_STANDALONE,
+        "freebsd" => elf::ELFOSABI_FREEBSD,
+        "solaris" => elf::ELFOSABI_SOLARIS,
+        _ => elf::ELFOSABI_NONE,
     };
+    let abi_version = 0;
+    file.flags = FileFlags::Elf { os_abi, abi_version, e_flags };
     Some(file)
 }