[RISCV] Add built-in target riscv32imac-unknown-none-elf.

src/librustc_target/spec/mod.rs

@@ -377,6 +377,8 @@ supported_targets! {
 
     ("aarch64-unknown-hermit", aarch64_unknown_hermit),
     ("x86_64-unknown-hermit", x86_64_unknown_hermit),
+
+    ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
 }
 
 /// Everything `rustc` knows about how to compile for a specific target.

src/librustc_target/spec/riscv32imac_unknown_none_elf.rs

@@ -0,0 +1,51 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use spec::{LinkerFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
+use spec::abi::{Abi};
+
+pub fn target() -> TargetResult {
+    Ok(Target {
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S128".to_string(),
+        llvm_target: "riscv32".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "32".to_string(),
+        target_c_int_width: "32".to_string(),
+        target_os: "none".to_string(),
+        target_env: "".to_string(),
+        target_vendor: "unknown".to_string(),
+        arch: "riscv32".to_string(),
+        linker_flavor: LinkerFlavor::Ld,
+
+        options: TargetOptions {
+            linker: Some("riscv32-unknown-elf-ld".to_string()),
+            cpu: "generic-rv32".to_string(),
+            max_atomic_width: Some(32),
+            features: "+m,+a,+c".to_string(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: "static".to_string(),
+            abi_blacklist: vec![
+                Abi::Cdecl,
+                Abi::Stdcall,
+                Abi::Fastcall,
+                Abi::Vectorcall,
+                Abi::Thiscall,
+                Abi::Aapcs,
+                Abi::Win64,
+                Abi::SysV64,
+                Abi::PtxKernel,
+                Abi::Msp430Interrupt,
+                Abi::X86Interrupt,
+            ],
+            .. Default::default()
+        },
+    })
+}