Add some no_std Xtensa targets

ESP32, ESP32S2, ESP32S3 & ESP8266.

Author: MabezDev

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

@@ -35,3 +35,4 @@ pub(crate) mod windows_gnullvm;
 pub(crate) mod windows_msvc;
 pub(crate) mod windows_uwp_gnu;
 pub(crate) mod windows_uwp_msvc;
+pub(crate) mod xtensa;

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

@@ -0,0 +1,17 @@
+use crate::spec::{LinkerFlavor, Cc, PanicStrategy, RelocModel, TargetOptions, Lld};
+use crate::abi::Endian;
+
+pub fn opts() -> TargetOptions {
+    TargetOptions {
+        os: "none".into(),
+        endian: Endian::Little,
+        c_int_width: "32".into(),
+        linker_flavor: LinkerFlavor::Gnu(Cc::Yes, Lld::No),
+        executables: true,
+        panic_strategy: PanicStrategy::Abort,
+        relocation_model: RelocModel::Static,
+        emit_debug_gdb_scripts: false,
+        atomic_cas: false,
+        ..Default::default()
+    }
+}

compiler/rustc_target/src/spec/mod.rs

@@ -1665,6 +1665,11 @@ supported_targets! {
 
     ("nvptx64-nvidia-cuda", nvptx64_nvidia_cuda),
 
+    ("xtensa-esp32-none-elf", xtensa_esp32_none_elf),
+    ("xtensa-esp32s2-none-elf", xtensa_esp32s2_none_elf),
+    ("xtensa-esp8266-none-elf", xtensa_esp8266_none_elf),
+    ("xtensa-esp32s3-none-elf", xtensa_esp32s3_none_elf),
+
     ("i686-wrs-vxworks", i686_wrs_vxworks),
     ("x86_64-wrs-vxworks", x86_64_wrs_vxworks),
     ("armv7-wrs-vxworks-eabihf", armv7_wrs_vxworks_eabihf),

compiler/rustc_target/src/spec/targets/xtensa_esp32_none_elf.rs

@@ -0,0 +1,19 @@
+use crate::spec::{Target, TargetOptions, base::xtensa};
+
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "xtensa-none-elf".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-i64:64-i128:128-n32".into(),
+        arch: "xtensa".into(),
+        
+        options: TargetOptions {
+            cpu: "esp32".into(),
+            linker: Some("xtensa-esp32-elf-gcc".into()),
+            max_atomic_width: Some(32),
+            atomic_cas: true,
+            ..xtensa::opts()
+        },
+    }
+}

compiler/rustc_target/src/spec/targets/xtensa_esp32s2_none_elf.rs

@@ -0,0 +1,17 @@
+use crate::spec::{Target, TargetOptions, base::xtensa};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "xtensa-none-elf".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-i64:64-i128:128-n32".into(),
+        arch: "xtensa".into(),
+        
+        options: TargetOptions {
+            cpu: "esp32-s2".into(),
+            linker: Some("xtensa-esp32s2-elf-gcc".into()),
+            max_atomic_width: Some(32),
+            ..xtensa::opts()
+        },
+    }
+}

compiler/rustc_target/src/spec/targets/xtensa_esp32s3_none_elf.rs

@@ -0,0 +1,18 @@
+use crate::spec::{Target, TargetOptions, base::xtensa};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "xtensa-none-elf".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-i64:64-i128:128-n32".into(),
+        arch: "xtensa".into(),
+        
+        options: TargetOptions {
+            cpu: "esp32-s3".into(),
+            linker: Some("xtensa-esp32s3-elf-gcc".into()),
+            max_atomic_width: Some(32),
+            atomic_cas: true,
+            ..xtensa::opts()
+        },
+    }
+}

compiler/rustc_target/src/spec/targets/xtensa_esp8266_none_elf.rs

@@ -0,0 +1,17 @@
+use crate::spec::{Target, TargetOptions, base::xtensa};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "xtensa-none-elf".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-i64:64-i128:128-n32".into(),
+        arch: "xtensa".into(),
+        
+        options: TargetOptions {
+            cpu: "esp8266".into(),
+            linker: Some("xtensa-lx106-elf-gcc".into()),
+            max_atomic_width: Some(32),
+            ..xtensa::opts()
+        },
+    }
+}