Rollup merge of #132354 - koute:master, r=workingjubilee

Add `lp64e` RISC-V ABI

This PR adds support for the `lp64e` RISC-V ABI, which is the 64-bit equivalent of the `ilp32e` ABI that is already supported.

For reference, this ABI was originally added to LLVM in [this PR](https://reviews.llvm.org/D70401).

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -325,7 +325,8 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
                 "" | "ilp32" | "lp64" => (),
                 "ilp32f" | "lp64f" => e_flags |= elf::EF_RISCV_FLOAT_ABI_SINGLE,
                 "ilp32d" | "lp64d" => e_flags |= elf::EF_RISCV_FLOAT_ABI_DOUBLE,
-                "ilp32e" => e_flags |= elf::EF_RISCV_RVE,
+                // Note that the `lp64e` is still unstable as it's not (yet) part of the ELF psABI.
+                "ilp32e" | "lp64e" => e_flags |= elf::EF_RISCV_RVE,
                 _ => bug!("unknown RISC-V ABI name"),
             }
 

compiler/rustc_target/src/spec/tests/tests_impl.rs

@@ -165,7 +165,8 @@ impl Target {
                 assert_matches!(&*self.llvm_abiname, "ilp32" | "ilp32f" | "ilp32d" | "ilp32e")
             }
             "riscv64" => {
-                assert_matches!(&*self.llvm_abiname, "lp64" | "lp64f" | "lp64d" | "lp64q")
+                // Note that the `lp64e` is still unstable as it's not (yet) part of the ELF psABI.
+                assert_matches!(&*self.llvm_abiname, "lp64" | "lp64f" | "lp64d" | "lp64q" | "lp64e")
             }
             _ => {}
         }