STD support for the ESP-IDF framework

2 files changed, 38 insertions, 0 deletions

diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 9c957cba6cc..218fa0344b6 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -903,6 +903,7 @@ supported_targets! {
 
     ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
     ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
+    ("riscv32imc-esp-espidf", riscv32imc_esp_espidf),
     ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
     ("riscv32gc-unknown-linux-gnu", riscv32gc_unknown_linux_gnu),
     ("riscv32gc-unknown-linux-musl", riscv32gc_unknown_linux_musl),
diff --git a/compiler/rustc_target/src/spec/riscv32imc_esp_espidf.rs b/compiler/rustc_target/src/spec/riscv32imc_esp_espidf.rs
new file mode 100644
index 00000000000..fb084afe960
--- /dev/null
+++ b/compiler/rustc_target/src/spec/riscv32imc_esp_espidf.rs
@@ -0,0 +1,37 @@
+use crate::spec::{LinkerFlavor, PanicStrategy, RelocModel};
+use crate::spec::{Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S128".to_string(),
+        llvm_target: "riscv32".to_string(),
+        pointer_width: 32,
+        arch: "riscv32".to_string(),
+
+        options: TargetOptions {
+            families: vec!["unix".to_string()],
+            os: "espidf".to_string(),
+            env: "newlib".to_string(),
+            vendor: "espressif".to_string(),
+            linker_flavor: LinkerFlavor::Gcc,
+            linker: Some("riscv32-esp-elf-gcc".to_string()),
+            cpu: "generic-rv32".to_string(),
+
+            // While the RiscV32IMC architecture does not natively support atomics, ESP-IDF does support
+            // the __atomic* and __sync* GCC builtins, so setting `max_atomic_width` to `Some(32)`
+            // and `atomic_cas` to `true` will cause the compiler to emit libcalls to these builtins.
+            //
+            // Support for atomics is necessary for the Rust STD library, which is supported by the ESP-IDF framework.
+            max_atomic_width: Some(32),
+            atomic_cas: true,
+
+            features: "+m,+c".to_string(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            emit_debug_gdb_scripts: false,
+            eh_frame_header: false,
+            ..Default::default()
+        },
+    }
+}