Initial support for riscv32{e|em|emc}_unknown_none_elf

compiler/rustc_target/src/spec/mod.rs

@@ -1841,6 +1841,10 @@ supported_targets! {
     ("riscv32imac-esp-espidf", riscv32imac_esp_espidf),
     ("riscv32imafc-esp-espidf", riscv32imafc_esp_espidf),
 
+    ("riscv32e-unknown-none-elf", riscv32e_unknown_none_elf),
+    ("riscv32em-unknown-none-elf", riscv32em_unknown_none_elf),
+    ("riscv32emc-unknown-none-elf", riscv32emc_unknown_none_elf),
+
     ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
     ("riscv32imafc-unknown-none-elf", riscv32imafc_unknown_none_elf),
     ("riscv32imac-unknown-xous-elf", riscv32imac_unknown_xous_elf),

compiler/rustc_target/src/spec/targets/riscv32e_unknown_none_elf.rs

@@ -0,0 +1,34 @@
+use crate::spec::{Cc, LinkerFlavor, Lld, PanicStrategy, RelocModel, Target, TargetOptions};
+
+pub(crate) fn target() -> Target {
+    Target {
+        // The below `data_layout` is explicitly specified by the ilp32e ABI in LLVM. See also
+        // `options.llvm_abiname`.
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S32".into(),
+        llvm_target: "riscv32".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("Bare RISC-V (RV32E ISA)".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(false),
+        },
+        pointer_width: 32,
+        arch: "riscv32".into(),
+
+        options: TargetOptions {
+            linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
+            linker: Some("rust-lld".into()),
+            cpu: "generic-rv32".into(),
+            // The ilp32e ABI specifies the `data_layout`
+            llvm_abiname: "ilp32e".into(),
+            max_atomic_width: Some(32),
+            atomic_cas: false,
+            features: "+e,+forced-atomics".into(),
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            emit_debug_gdb_scripts: false,
+            eh_frame_header: false,
+            ..Default::default()
+        },
+    }
+}

compiler/rustc_target/src/spec/targets/riscv32em_unknown_none_elf.rs

@@ -0,0 +1,34 @@
+use crate::spec::{Cc, LinkerFlavor, Lld, PanicStrategy, RelocModel, Target, TargetOptions};
+
+pub(crate) fn target() -> Target {
+    Target {
+        // The below `data_layout` is explicitly specified by the ilp32e ABI in LLVM. See also
+        // `options.llvm_abiname`.
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S32".into(),
+        llvm_target: "riscv32".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("Bare RISC-V (RV32EM ISA)".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(false),
+        },
+        pointer_width: 32,
+        arch: "riscv32".into(),
+
+        options: TargetOptions {
+            linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
+            linker: Some("rust-lld".into()),
+            cpu: "generic-rv32".into(),
+            // The ilp32e ABI specifies the `data_layout`
+            llvm_abiname: "ilp32e".into(),
+            max_atomic_width: Some(32),
+            atomic_cas: false,
+            features: "+e,+m,+forced-atomics".into(),
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            emit_debug_gdb_scripts: false,
+            eh_frame_header: false,
+            ..Default::default()
+        },
+    }
+}

compiler/rustc_target/src/spec/targets/riscv32emc_unknown_none_elf.rs

@@ -0,0 +1,34 @@
+use crate::spec::{Cc, LinkerFlavor, Lld, PanicStrategy, RelocModel, Target, TargetOptions};
+
+pub(crate) fn target() -> Target {
+    Target {
+        // The below `data_layout` is explicitly specified by the ilp32e ABI in LLVM. See also
+        // `options.llvm_abiname`.
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S32".into(),
+        llvm_target: "riscv32".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("Bare RISC-V (RV32EMC ISA)".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(false),
+        },
+        pointer_width: 32,
+        arch: "riscv32".into(),
+
+        options: TargetOptions {
+            linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
+            linker: Some("rust-lld".into()),
+            cpu: "generic-rv32".into(),
+            // The ilp32e ABI specifies the `data_layout`
+            llvm_abiname: "ilp32e".into(),
+            max_atomic_width: Some(32),
+            atomic_cas: false,
+            features: "+e,+m,+c,+forced-atomics".into(),
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            emit_debug_gdb_scripts: false,
+            eh_frame_header: false,
+            ..Default::default()
+        },
+    }
+}

src/bootstrap/src/core/sanity.rs

@@ -37,6 +37,9 @@ pub struct Finder {
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     // just a dummy comment so the list doesn't get onelined
     "armv7-rtems-eabihf",
+    "riscv32e-unknown-none-elf",
+    "riscv32em-unknown-none-elf",
+    "riscv32emc-unknown-none-elf",
 ];
 
 /// Minimum version threshold for libstdc++ required when using prebuilt LLVM

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

@@ -413,5 +413,8 @@ target | std | host | notes
 [`riscv32imafc-unknown-nuttx-elf`](platform-support/nuttx.md) | * |  | RISC-V 32bit with NuttX
 [`riscv64imac-unknown-nuttx-elf`](platform-support/nuttx.md) | * |  | RISC-V 64bit with NuttX
 [`riscv64gc-unknown-nuttx-elf`](platform-support/nuttx.md) | * |  | RISC-V 64bit with NuttX
+[`riscv32e-unknown-none-elf`](platform-support/riscv32-unknown-none-elf.md) | * |  | Bare RISC-V (RV32E ISA)
+[`riscv32em-unknown-none-elf`](platform-support/riscv32-unknown-none-elf.md) | * |  | Bare RISC-V (RV32EM ISA)
+[`riscv32emc-unknown-none-elf`](platform-support/riscv32-unknown-none-elf.md) | * |  | Bare RISC-V (RV32EMC ISA)
 
 [runs on NVIDIA GPUs]: https://github.com/japaric-archived/nvptx#targets

src/doc/rustc/src/platform-support/riscv32-unknown-none-elf.md

@@ -35,4 +35,4 @@ Rust test-suite on this target.
 ## Cross-compilation toolchains and C code
 
 This target supports C code. If interlinking with C or C++, you may need to use
-`riscv64-unknown-elf-gcc` as a linker instead of `rust-lld`.
+`riscv32-unknown-elf-gcc` as a linker instead of `rust-lld`.

src/doc/rustc/src/platform-support/riscv32e-unknown-none-elf.md

@@ -0,0 +1,30 @@
+# `riscv32{e,em,emc}-unknown-none-elf`
+
+**Tier: 3**
+
+Bare-metal target for RISC-V CPUs with the RV32E, RV32EM and RV32EMC ISAs.
+
+## Target maintainers
+
+* Henri Lunnikivi, <henri.lunnikivi@gmail.com>, [@hegza](https://github.com/hegza)
+
+## Requirements
+
+The target is cross-compiled, and uses static linking. No external toolchain is
+required and the default `rust-lld` linker works, but you must specify a linker
+script.
+
+## Building the target
+
+This target is included in Rust and can be installed via `rustup`.
+
+## Testing
+
+This is a cross-compiled `no-std` target, which must be run either in a
+simulator or by programming them onto suitable hardware. It is not possible to
+run the Rust test-suite on this target.
+
+## Cross-compilation toolchains and C code
+
+This target supports C code. If interlinking with C or C++, you may need to use
+`riscv32-unknown-elf-gcc` as a linker instead of `rust-lld`.

tests/assembly/targets/targets-elf.rs

@@ -375,6 +375,15 @@
 //@ revisions: riscv32_wrs_vxworks
 //@ [riscv32_wrs_vxworks] compile-flags: --target riscv32-wrs-vxworks
 //@ [riscv32_wrs_vxworks] needs-llvm-components: riscv
+//@ revisions: riscv32e_unknown_none_elf
+//@ [riscv32e_unknown_none_elf] compile-flags: --target riscv32e-unknown-none-elf
+//@ [riscv32e_unknown_none_elf] needs-llvm-components: riscv
+//@ revisions: riscv32em_unknown_none_elf
+//@ [riscv32em_unknown_none_elf] compile-flags: --target riscv32em-unknown-none-elf
+//@ [riscv32em_unknown_none_elf] needs-llvm-components: riscv
+//@ revisions: riscv32emc_unknown_none_elf
+//@ [riscv32emc_unknown_none_elf] compile-flags: --target riscv32emc-unknown-none-elf
+//@ [riscv32emc_unknown_none_elf] needs-llvm-components: riscv
 //@ revisions: riscv32gc_unknown_linux_gnu
 //@ [riscv32gc_unknown_linux_gnu] compile-flags: --target riscv32gc-unknown-linux-gnu
 //@ [riscv32gc_unknown_linux_gnu] needs-llvm-components: riscv

tests/ui/abi/riscv32e-registers.riscv32e.stderr

@@ -0,0 +1,194 @@
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:43:11
+   |
+LL |     asm!("li x16, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x16, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:46:11
+   |
+LL |     asm!("li x17, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x17, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:49:11
+   |
+LL |     asm!("li x18, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x18, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:52:11
+   |
+LL |     asm!("li x19, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x19, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:55:11
+   |
+LL |     asm!("li x20, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x20, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:58:11
+   |
+LL |     asm!("li x21, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x21, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:61:11
+   |
+LL |     asm!("li x22, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x22, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:64:11
+   |
+LL |     asm!("li x23, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x23, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:67:11
+   |
+LL |     asm!("li x24, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x24, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:70:11
+   |
+LL |     asm!("li x25, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x25, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:73:11
+   |
+LL |     asm!("li x26, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x26, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:76:11
+   |
+LL |     asm!("li x27, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x27, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:79:11
+   |
+LL |     asm!("li x28, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x28, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:82:11
+   |
+LL |     asm!("li x29, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x29, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:85:11
+   |
+LL |     asm!("li x30, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x30, 0
+   |        ^
+
+error: invalid operand for instruction
+  --> $DIR/riscv32e-registers.rs:88:11
+   |
+LL |     asm!("li x31, 0");
+   |           ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:1:5
+   |
+LL |     li x31, 0
+   |        ^
+
+error: aborting due to 16 previous errors
+