Couple of changes for Redox OS

compiler/rustc_target/src/spec/base/redox.rs

@@ -12,7 +12,7 @@ pub(crate) fn opts() -> TargetOptions {
         has_thread_local: true,
         crt_static_default: true,
         crt_static_respected: true,
-        crt_static_allows_dylibs: true,
+        crt_static_allows_dylibs: false,
         late_link_args: TargetOptions::link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-lgcc"]),
         ..Default::default()
     }

compiler/rustc_target/src/spec/mod.rs

@@ -1553,6 +1553,7 @@ supported_targets! {
 
     ("aarch64-unknown-redox", aarch64_unknown_redox),
     ("i586-unknown-redox", i586_unknown_redox),
+    ("riscv64gc-unknown-redox", riscv64gc_unknown_redox),
     ("x86_64-unknown-redox", x86_64_unknown_redox),
 
     ("x86_64-unknown-managarm-mlibc", x86_64_unknown_managarm_mlibc),

compiler/rustc_target/src/spec/targets/riscv64gc_unknown_redox.rs

@@ -0,0 +1,25 @@
+use crate::spec::{CodeModel, Target, TargetMetadata, base};
+
+pub(crate) fn target() -> Target {
+    let mut base = base::redox::opts();
+    base.code_model = Some(CodeModel::Medium);
+    base.cpu = "generic-rv64".into();
+    base.features = "+m,+a,+f,+d,+c".into();
+    base.llvm_abiname = "lp64d".into();
+    base.plt_by_default = false;
+    base.max_atomic_width = Some(64);
+
+    Target {
+        llvm_target: "riscv64-unknown-redox".into(),
+        metadata: TargetMetadata {
+            description: Some("Redox OS".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(true),
+        },
+        pointer_width: 64,
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
+        arch: "riscv64".into(),
+        options: base,
+    }
+}

src/bootstrap/src/core/sanity.rs

@@ -34,6 +34,7 @@ pub struct Finder {
 // Targets can be removed from this list once they are present in the stage0 compiler (usually by updating the beta compiler of the bootstrap).
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     // just a dummy comment so the list doesn't get onelined
+    "riscv64gc-unknown-redox",
 ];
 
 /// Minimum version threshold for libstdc++ required when using prebuilt LLVM

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

@@ -393,6 +393,7 @@ target | std | host | notes
 [`riscv64gc-unknown-netbsd`](platform-support/netbsd.md) | ✓ | ✓ | RISC-V NetBSD
 [`riscv64gc-unknown-nuttx-elf`](platform-support/nuttx.md) | ✓ |  | RISC-V 64bit with NuttX
 [`riscv64gc-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | OpenBSD/riscv64
+[`riscv64gc-unknown-redox`](platform-support/redox.md) | ✓ |  | RISC-V 64bit Redox OS
 [`riscv64imac-unknown-nuttx-elf`](platform-support/nuttx.md) | ✓ |  | RISC-V 64bit with NuttX
 [`riscv64a23-unknown-linux-gnu`](platform-support/riscv64a23-unknown-linux-gnu.md) | ✓ | ✓ | RISC-V Linux (kernel 6.8.0+, glibc 2.39)
 [`s390x-unknown-linux-musl`](platform-support/s390x-unknown-linux-musl.md) | ✓ |  | S390x Linux (kernel 3.2, musl 1.2.3)

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

@@ -10,6 +10,7 @@ Target triplets available so far:
 - `x86_64-unknown-redox` (tier 2)
 - `aarch64-unknown-redox` (tier 3)
 - `i586-unknown-redox` (tier 3)
+- `riscv64gc-unknown-redox` (tier 3)
 
 ## Target maintainers
 
@@ -37,6 +38,7 @@ target = [
     "x86_64-unknown-redox",
     "aarch64-unknown-redox",
     "i586-unknown-redox",
+    "riscv64gc-unknown-redox",
 ]
 ```
 

tests/assembly-llvm/targets/targets-elf.rs

@@ -505,6 +505,9 @@
 //@ revisions: riscv64gc_unknown_openbsd
 //@ [riscv64gc_unknown_openbsd] compile-flags: --target riscv64gc-unknown-openbsd
 //@ [riscv64gc_unknown_openbsd] needs-llvm-components: riscv
+//@ revisions: riscv64gc_unknown_redox
+//@ [riscv64gc_unknown_redox] compile-flags: --target riscv64gc-unknown-redox
+//@ [riscv64gc_unknown_redox] needs-llvm-components: riscv
 //@ revisions: riscv64imac_unknown_none_elf
 //@ [riscv64imac_unknown_none_elf] compile-flags: --target riscv64imac-unknown-none-elf
 //@ [riscv64imac_unknown_none_elf] needs-llvm-components: riscv