Rollup merge of rust-lang#62784 - Disasm:riscv32i, r=estebank

Add riscv32i-unknown-none-elf target

This target is likely to be useful for constrained FPGA soft-cores, such as picorv32 and HeavyX.

src/ci/docker/dist-various-1/Dockerfile

@@ -112,6 +112,7 @@ ENV TARGETS=$TARGETS,thumbv7em-none-eabihf
 ENV TARGETS=$TARGETS,thumbv8m.base-none-eabi
 ENV TARGETS=$TARGETS,thumbv8m.main-none-eabi
 ENV TARGETS=$TARGETS,thumbv8m.main-none-eabihf
+ENV TARGETS=$TARGETS,riscv32i-unknown-none-elf
 ENV TARGETS=$TARGETS,riscv32imc-unknown-none-elf
 ENV TARGETS=$TARGETS,riscv32imac-unknown-none-elf
 ENV TARGETS=$TARGETS,riscv64imac-unknown-none-elf

src/librustc_target/spec/mod.rs

@@ -464,6 +464,7 @@ supported_targets! {
     ("aarch64-unknown-hermit", aarch64_unknown_hermit),
     ("x86_64-unknown-hermit", x86_64_unknown_hermit),
 
+    ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
     ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
     ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
     ("riscv64imac-unknown-none-elf", riscv64imac_unknown_none_elf),

src/librustc_target/spec/riscv32i_unknown_none_elf.rs

@@ -0,0 +1,32 @@
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy,
+           Target, TargetOptions, TargetResult};
+
+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: String::new(),
+        target_vendor: "unknown".to_string(),
+        arch: "riscv32".to_string(),
+        linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
+
+        options: TargetOptions {
+            linker: Some("rust-lld".to_string()),
+            cpu: "generic-rv32".to_string(),
+            max_atomic_width: None,
+            atomic_cas: false,
+            features: String::new(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: "static".to_string(),
+            emit_debug_gdb_scripts: false,
+            abi_blacklist: super::riscv_base::abi_blacklist(),
+            eliminate_frame_pointer: false,
+            .. Default::default()
+        },
+    })
+}

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

@@ -92,6 +92,7 @@ static TARGETS: &[&str] = &[
     "powerpc-unknown-linux-gnu",
     "powerpc64-unknown-linux-gnu",
     "powerpc64le-unknown-linux-gnu",
+    "riscv32i-unknown-none-elf",
     "riscv32imc-unknown-none-elf",
     "riscv32imac-unknown-none-elf",
     "riscv64imac-unknown-none-elf",