Auto merge of #159010 - bjorn3:refactor_unwind, r=<try>

Simplify the unwind crate


try-job: dist-various*
try-job:

Author: bors

library/panic_unwind/src/gcc.rs

@@ -63,7 +63,7 @@ pub(crate) unsafe fn panic(data: Box<dyn Any + Send>) -> u32 {
         _uwe: uw::_Unwind_Exception {
             exception_class: RUST_EXCEPTION_CLASS,
             exception_cleanup: Some(exception_cleanup),
-            private: [core::ptr::null(); uw::unwinder_private_data_size],
+            private: [core::ptr::null(); _],
         },
         canary: &CANARY,
         cause: data,

library/unwind/Cargo.toml

@@ -4,9 +4,6 @@ version = "0.0.0"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/rust.git"
 edition = "2024"
-include = [
-  '/libunwind/*',
-]
 
 [lib]
 test = false

library/unwind/src/lib.rs

@@ -33,14 +33,11 @@ cfg_select! {
         target_os = "solid_asp3",
         all(target_vendor = "fortanix", target_env = "sgx"),
         all(target_os = "wasi", panic = "unwind"),
+        target_os = "xous",
     ) => {
         mod libunwind;
         pub use libunwind::*;
     }
-    target_os = "xous" => {
-        mod unwinding;
-        pub use unwinding::*;
-    }
     target_family = "wasm" => {
         mod wasm;
         pub use wasm::*;

library/unwind/src/libunwind.rs

@@ -2,6 +2,12 @@
 
 use core::ffi::{c_int, c_void};
 
+// Use the unwinding crate as unwinder on Xous
+#[cfg(target_os = "xous")]
+pub use unwinding::custom_eh_frame_finder::{
+    EhFrameFinder, FrameInfo, FrameInfoKind, set_custom_eh_frame_finder,
+};
+
 #[repr(C)]
 #[derive(Debug, Copy, Clone, PartialEq)]
 pub enum _Unwind_Reason_Code {
@@ -24,65 +30,28 @@ pub type _Unwind_Ptr = *const u8;
 pub type _Unwind_Trace_Fn =
     extern "C" fn(ctx: *mut _Unwind_Context, arg: *mut c_void) -> _Unwind_Reason_Code;
 
-#[cfg(target_arch = "x86")]
-pub const unwinder_private_data_size: usize = 5;
-
-#[cfg(all(target_arch = "x86_64", not(any(target_os = "windows", target_os = "cygwin"))))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(all(target_arch = "x86_64", any(target_os = "windows", target_os = "cygwin")))]
-pub const unwinder_private_data_size: usize = 6;
-
-#[cfg(all(target_arch = "arm", not(target_vendor = "apple")))]
-pub const unwinder_private_data_size: usize = 20;
-
-#[cfg(all(target_arch = "arm", target_vendor = "apple"))]
-pub const unwinder_private_data_size: usize = 5;
-
-#[cfg(all(target_arch = "aarch64", target_pointer_width = "64", not(target_os = "windows")))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(all(target_arch = "aarch64", target_pointer_width = "64", target_os = "windows"))]
-pub const unwinder_private_data_size: usize = 6;
-
-#[cfg(all(target_arch = "aarch64", target_pointer_width = "32"))]
-pub const unwinder_private_data_size: usize = 5;
-
-#[cfg(target_arch = "m68k")]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(any(target_arch = "mips", target_arch = "mips32r6"))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(target_arch = "csky")]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(any(target_arch = "mips64", target_arch = "mips64r6"))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(any(target_arch = "powerpc", target_arch = "powerpc64"))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(target_arch = "s390x")]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(any(target_arch = "sparc", target_arch = "sparc64"))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(any(target_arch = "riscv64", target_arch = "riscv32"))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(all(target_family = "wasm", target_os = "emscripten"))]
-pub const unwinder_private_data_size: usize = 20;
-
-#[cfg(all(target_arch = "wasm32", any(target_os = "linux", target_os = "wasi")))]
-pub const unwinder_private_data_size: usize = 2;
-
-#[cfg(target_arch = "hexagon")]
-pub const unwinder_private_data_size: usize = 5;
-
-#[cfg(any(target_arch = "loongarch32", target_arch = "loongarch64"))]
-pub const unwinder_private_data_size: usize = 2;
+pub const unwinder_private_data_size: usize = cfg_select! {
+    target_arch = "x86" => 5,
+    all(target_arch = "x86_64", not(any(target_os = "windows", target_os = "cygwin"))) => 2,
+    all(target_arch = "x86_64", any(target_os = "windows", target_os = "cygwin")) => 6,
+    all(target_arch = "arm", not(target_vendor = "apple")) => 20,
+    all(target_arch = "arm", target_vendor = "apple") => 5,
+    all(target_arch = "aarch64", target_pointer_width = "64", not(target_os = "windows")) => 2,
+    all(target_arch = "aarch64", target_pointer_width = "64", target_os = "windows") => 6,
+    all(target_arch = "aarch64", target_pointer_width = "32") => 5,
+    target_arch = "m68k" => 2,
+    any(target_arch = "mips", target_arch = "mips32r6") => 2,
+    target_arch = "csky" => 2,
+    any(target_arch = "mips64", target_arch = "mips64r6") => 2,
+    any(target_arch = "powerpc", target_arch = "powerpc64") => 2,
+    target_arch = "s390x" => 2,
+    any(target_arch = "sparc", target_arch = "sparc64") => 2,
+    any(target_arch = "riscv64", target_arch = "riscv32") => 2,
+    all(target_family = "wasm", target_os = "emscripten") => 20,
+    all(target_arch = "wasm32", any(target_os = "linux", target_os = "wasi")) => 2,
+    target_arch = "hexagon" => 5,
+    any(target_arch = "loongarch32", target_arch = "loongarch64") => 2,
+};
 
 #[repr(C)]
 pub struct _Unwind_Exception {
@@ -91,6 +60,12 @@ pub struct _Unwind_Exception {
     pub private: [_Unwind_Word; unwinder_private_data_size],
 }
 
+// Check the size of _Unwind_Exception against the source of thruth when using the unwinding crate.
+#[cfg(target_os = "xous")]
+const _: () = {
+    assert!(size_of::<unwinding::abi::UnwindException>() == size_of::<_Unwind_Exception>());
+};
+
 pub enum _Unwind_Context {}
 
 pub type _Unwind_Exception_Cleanup_Fn =
@@ -105,10 +80,7 @@ pub type _Unwind_Exception_Cleanup_Fn =
 // rustc_codegen_ssa::src::back::symbol_export, rustc_middle::middle::exported_symbols
 // and RFC 2841
 #[cfg_attr(
-    all(
-        feature = "llvm-libunwind",
-        any(target_os = "fuchsia", target_os = "linux", target_os = "xous")
-    ),
+    all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
     link(name = "unwind", kind = "static", modifiers = "-bundle")
 )]
 // Explicitly link the `unwind` library on WASI targets.
@@ -144,7 +116,7 @@ cfg_select! {
         pub const _UA_END_OF_STACK: c_int = 16;
 
         #[cfg_attr(
-            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux", target_os = "xous")),
+            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
             link(name = "unwind", kind = "static", modifiers = "-bundle")
         )]
         unsafe extern "C" {
@@ -203,7 +175,7 @@ cfg_select! {
         pub const UNWIND_IP_REG: c_int = 15;
 
         #[cfg_attr(
-            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux", target_os = "xous")),
+            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
             link(name = "unwind", kind = "static", modifiers = "-bundle")
         )]
         unsafe extern "C" {
@@ -283,14 +255,14 @@ cfg_select! {
     }
     _ => {
         #[cfg_attr(
-            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux", target_os = "xous")),
+            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
             link(name = "unwind", kind = "static", modifiers = "-bundle")
         )]
         unsafe extern "C-unwind" {
             pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
         }
         #[cfg_attr(
-            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux", target_os = "xous")),
+            all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
             link(name = "unwind", kind = "static", modifiers = "-bundle")
         )]
         unsafe extern "C" {

library/unwind/src/unwinding.rs

@@ -27,7 +27,7 @@ fn panic(data: Box<dyn Any + Send>) -> u32 {
         _uwe: uw::_Unwind_Exception {
             exception_class: miri_exception_class(),
             exception_cleanup: Some(exception_cleanup),
-            private: [core::ptr::null(); uw::unwinder_private_data_size],
+            private: [core::ptr::null(); _],
         },
         cause: data,
     });