compiler: Add riscv64gc-unknown-hermit target

Co-authored-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>
Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>

compiler/rustc_target/src/spec/mod.rs

@@ -1418,6 +1418,7 @@ fn $module() {
     ("msp430-none-elf", msp430_none_elf),
 
     ("aarch64-unknown-hermit", aarch64_unknown_hermit),
+    ("riscv64gc-unknown-hermit", riscv64gc_unknown_hermit),
     ("x86_64-unknown-hermit", x86_64_unknown_hermit),
 
     ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),

compiler/rustc_target/src/spec/riscv64gc_unknown_hermit.rs

@@ -0,0 +1,20 @@
+use crate::spec::{CodeModel, RelocModel, Target, TargetOptions, TlsModel};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "riscv64-unknown-hermit".into(),
+        pointer_width: 64,
+        arch: "riscv64".into(),
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
+        options: TargetOptions {
+            cpu: "generic-rv64".into(),
+            features: "+m,+a,+f,+d,+c".into(),
+            relocation_model: RelocModel::Pic,
+            code_model: Some(CodeModel::Medium),
+            tls_model: TlsModel::LocalExec,
+            max_atomic_width: Some(64),
+            llvm_abiname: "lp64d".into(),
+            ..super::hermit_base::opts()
+        },
+    }
+}

src/tools/build-manifest/src/main.rs

@@ -122,6 +122,7 @@
     "riscv32imac-unknown-none-elf",
     "riscv32gc-unknown-linux-gnu",
     "riscv64imac-unknown-none-elf",
+    "riscv64gc-unknown-hermit",
     "riscv64gc-unknown-none-elf",
     "riscv64gc-unknown-linux-gnu",
     "s390x-unknown-linux-gnu",