Add the esp-backtrace package to the repository (#1583)

Cargo.toml

@@ -3,6 +3,7 @@ resolver = "2"
 members  = ["xtask"]
 exclude  = [
     "esp-alloc",
+    "esp-backtrace",
     "esp-build",
     "esp-hal",
     "esp-hal-procmacros",

esp-backtrace/Cargo.toml

@@ -0,0 +1,45 @@
+[package]
+name        = "esp-backtrace"
+version     = "0.11.1"
+edition     = "2021"
+description = "Bare-metal backtrace support for ESP32"
+repository  = "https://github.com/esp-rs/esp-hal"
+license     = "MIT OR Apache-2.0"
+
+[package.metadata.docs.rs]
+default-target = "riscv32imc-unknown-none-elf"
+features       = ["esp32c3", "panic-handler", "exception-handler", "println", "esp-println/uart"]
+
+[dependencies]
+defmt       = { version = "0.3.6", optional = true }
+esp-println = { version = "0.9.1", optional = true, default-features = false, path = "../esp-println" }
+semihosting = { version = "0.1.7", optional = true }
+
+[build-dependencies]
+esp-build = { version = "0.1.0", path = "../esp-build" }
+
+[features]
+default = ["colors"]
+
+# You must enable exactly one of the below features to support the correct chip:
+esp32   = ["esp-println?/esp32", "semihosting?/openocd-semihosting"]
+esp32c2 = ["esp-println?/esp32c2"]
+esp32c3 = ["esp-println?/esp32c3"]
+esp32c6 = ["esp-println?/esp32c6"]
+esp32h2 = ["esp-println?/esp32h2"]
+esp32p4 = ["esp-println?/esp32p4"]
+esp32s2 = ["esp-println?/esp32s2", "semihosting?/openocd-semihosting"]
+esp32s3 = ["esp-println?/esp32s3", "semihosting?/openocd-semihosting"]
+
+# Use esp-println
+println = ["dep:esp-println"]
+
+# Use defmt
+defmt = ["dep:defmt"]
+
+# You may optionally enable one or more of the below features to provide
+# additional functionality:
+colors            = []
+exception-handler = []
+halt-cores        = []
+panic-handler     = []

esp-backtrace/README.md

@@ -0,0 +1,52 @@
+# esp-backtrace - backtrace for ESP32 bare-metal
+
+Supports the ESP32, ESP32-C2/C3/C6, ESP32-H2, ESP32-P4, and ESP32-S2/S3. Optional exception and panic handlers are included, both of which can be enabled via their respective features.
+
+Please note that when targeting a RISC-V device, you **need** to force frame pointers (i.e. `"-C", "force-frame-pointers",` in your `.cargo/config.toml`); this is **not** required for Xtensa.
+
+You can get an array of backtrace addresses (currently limited to 10) via `arch::backtrace()` if
+you want to create a backtrace yourself (i.e. not using the panic or exception handler).
+
+When using the panic and/or exception handler make sure to include `use esp_backtrace as _;`.
+
+## Features
+
+| Feature           | Description                                                                                                        |
+| ----------------- | ------------------------------------------------------------------------------------------------------------------ |
+| esp32             | Target ESP32                                                                                                       |
+| esp32c2           | Target ESP32-C2                                                                                                    |
+| esp32c3           | Target ESP32-C3                                                                                                    |
+| esp32c6           | Target ESP32-C6                                                                                                    |
+| esp32h2           | Target ESP32-H2                                                                                                    |
+| esp32p4           | Target ESP32-P4                                                                                                    |
+| esp32s2           | Target ESP32-S2                                                                                                    |
+| esp32s3           | Target ESP32-S3                                                                                                    |
+| panic-handler     | Include a panic handler, will add `esp-println` as a dependency                                                    |
+| exception-handler | Include an exception handler, will add `esp-println` as a dependency                                               |
+| println           | Use `esp-println` to print messages                                                                                |
+| defmt             | Use `defmt` logging to print messages\* (check [example](https://github.com/playfulFence/backtrace-defmt-example)) |
+| colors            | Print messages in red\*                                                                                            |
+| halt-cores        | Halt both CPUs on ESP32 / ESP32-S3 in case of a panic or exception                                                 |
+| semihosting       | Call `semihosting::process::abort()` on panic.                                                                     |
+
+\* _only used for panic and exception handlers_
+
+### `defmt` Feature
+
+Please note that `defmt` does _not_ provide MSRV guarantees with releases, and as such we are not able to make any MSRV guarantees when this feature is enabled. For more information refer to the MSRV section of `defmt`'s README:
+https://github.com/knurling-rs/defmt?tab=readme-ov-file#msrv
+
+## License
+
+Licensed under either of:
+
+- Apache License, Version 2.0 ([LICENSE-APACHE](../LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+- MIT license ([LICENSE-MIT](../LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in
+the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without
+any additional terms or conditions.

esp-backtrace/build.rs

@@ -0,0 +1,28 @@
+use esp_build::assert_unique_used_features;
+
+fn main() {
+    // Ensure that only a single chip is specified:
+    assert_unique_used_features!(
+        "esp32", "esp32c2", "esp32c3", "esp32c6", "esp32h2", "esp32p4", "esp32s2", "esp32s3"
+    );
+
+    // Ensure that exactly a backend is selected:
+    assert_unique_used_features!("defmt", "println");
+
+    if is_nightly() {
+        println!("cargo:rustc-cfg=nightly");
+    }
+}
+
+fn is_nightly() -> bool {
+    let version_output = std::process::Command::new(
+        std::env::var_os("RUSTC").unwrap_or_else(|| std::ffi::OsString::from("rustc")),
+    )
+    .arg("-V")
+    .output()
+    .unwrap()
+    .stdout;
+    let version_string = String::from_utf8_lossy(&version_output);
+
+    version_string.contains("nightly")
+}