Add support for NetBSD/riscv64 aka. riscv64gc-unknown-netbsd.

Author: he32

compiler/rustc_target/src/spec/mod.rs

@@ -1325,6 +1325,7 @@ supported_targets! {
     ("armv7-unknown-netbsd-eabihf", armv7_unknown_netbsd_eabihf),
     ("i686-unknown-netbsd", i686_unknown_netbsd),
     ("powerpc-unknown-netbsd", powerpc_unknown_netbsd),
+    ("riscv64gc-unknown-netbsd", riscv64gc_unknown_netbsd),
     ("sparc64-unknown-netbsd", sparc64_unknown_netbsd),
     ("x86_64-unknown-netbsd", x86_64_unknown_netbsd),
 

compiler/rustc_target/src/spec/riscv64gc_unknown_netbsd.rs

@@ -0,0 +1,19 @@
+use crate::spec::{CodeModel, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "riscv64-unknown-netbsd".into(),
+        pointer_width: 64,
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
+        arch: "riscv64".into(),
+        options: TargetOptions {
+            code_model: Some(CodeModel::Medium),
+            cpu: "generic-rv64".into(),
+            features: "+m,+a,+f,+d,+c".into(),
+            llvm_abiname: "lp64d".into(),
+            max_atomic_width: Some(64),
+            mcount: "__mcount".into(),
+            ..super::netbsd_base::opts()
+        },
+    }
+}

library/core/src/ffi/mod.rs

@@ -132,7 +132,12 @@ mod c_char_definition {
             ),
             all(
                 target_os = "netbsd",
-                any(target_arch = "aarch64", target_arch = "arm", target_arch = "powerpc")
+                any(
+                    target_arch = "aarch64",
+                    target_arch = "arm",
+                    target_arch = "powerpc",
+                    target_arch = "riscv64"
+                )
             ),
             all(
                 target_os = "vxworks",

src/bootstrap/llvm.rs

@@ -380,7 +380,10 @@ impl Step for Llvm {
             cfg.define("LLVM_LINK_LLVM_DYLIB", "ON");
         }
 
-        if target.starts_with("riscv") && !target.contains("freebsd") && !target.contains("openbsd")
+        if target.starts_with("riscv")
+            && !target.contains("freebsd")
+            && !target.contains("openbsd")
+            && !target.contains("netbsd")
         {
             // RISC-V GCC erroneously requires linking against
             // `libatomic` when using 1-byte and 2-byte C++

src/doc/rustc/src/platform-support.md

@@ -305,6 +305,7 @@ target | std | host | notes
 `riscv64gc-unknown-freebsd` |   |   | RISC-V FreeBSD
 `riscv64gc-unknown-fuchsia` |   |   | RISC-V Fuchsia
 `riscv64gc-unknown-linux-musl` |   |   | RISC-V Linux (kernel 4.20, musl 1.2.0)
+[`riscv64gc-unknown-netbsd`](platform-support/netbsd.md) | ✓ | ? | RISC-V NetBSD
 [`riscv64gc-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | OpenBSD/riscv64
 `s390x-unknown-linux-musl` |  |  | S390x Linux (kernel 3.2, MUSL)
 `sparc-unknown-linux-gnu` | ✓ |  | 32-bit SPARC Linux

src/doc/rustc/src/platform-support/netbsd.md

@@ -22,6 +22,7 @@ are currently defined running NetBSD:
 | `i686-unknown-netbsd`          | [32-bit i386 with SSE](https://wiki.netbsd.org/ports/i386/) |
 | `mipsel-unknown-netbsd`        | [32-bit mips, requires mips32 cpu support](https://wiki.netbsd.org/ports/evbmips/) |
 | `powerpc-unknown-netbsd`       | [Various 32-bit PowerPC systems, e.g. MacPPC](https://wiki.netbsd.org/ports/macppc/) |
+| `riscv64gc-unknown-netbsd`     | [64-bit RISC-V](https://wiki.netbsd.org/ports/riscv/)
 | `sparc64-unknown-netbsd`       | [Sun UltraSPARC systems](https://wiki.netbsd.org/ports/sparc64/) |
 
 All use the "native" `stdc++` library which goes along with the natively