Auto merge of #159785 - bjorn3:refactor_unwind2, r=clarfonthey

Share _Unwind_Exception definition between native and wasm

And a couple of minor cleanups.

Follow up to #159010

Author: bors

library/std/src/sys/personality/emcc.rs

@@ -14,9 +14,6 @@ mod dwarf;
 
 #[cfg(not(any(test, doctest)))]
 cfg_select! {
-    target_os = "emscripten" => {
-        mod emcc;
-    }
     any(target_env = "msvc", target_family = "wasm", target_os = "motor") => {
         // This is required by the compiler to exist (e.g., it's a lang item),
         // but it's never actually called by the compiler because

library/std/src/sys/personality/mod.rs

@@ -37,8 +37,10 @@ cfg_select! {
     ) => {
         mod libunwind;
         pub use libunwind::*;
+        mod types;
     }
     target_family = "wasm" => {
+        mod types;
         mod wasm;
         pub use wasm::*;
     }

library/unwind/src/lib.rs

@@ -8,69 +8,12 @@ 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 {
-    _URC_NO_REASON = 0,
-    _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
-    _URC_FATAL_PHASE2_ERROR = 2,
-    _URC_FATAL_PHASE1_ERROR = 3,
-    _URC_NORMAL_STOP = 4,
-    _URC_END_OF_STACK = 5,
-    _URC_HANDLER_FOUND = 6,
-    _URC_INSTALL_CONTEXT = 7,
-    _URC_CONTINUE_UNWIND = 8,
-    _URC_FAILURE = 9, // used only by ARM EHABI
-}
-pub use _Unwind_Reason_Code::*;
+pub use crate::types::*;
 
-pub type _Unwind_Exception_Class = u64;
-pub type _Unwind_Word = *const u8;
 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;
-
-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 {
-    pub exception_class: _Unwind_Exception_Class,
-    pub exception_cleanup: _Unwind_Exception_Cleanup_Fn,
-    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 =
-    Option<extern "C" fn(unwind_code: _Unwind_Reason_Code, exception: *mut _Unwind_Exception)>;
-
 // FIXME: The `#[link]` attributes on `extern "C"` block marks those symbols declared in
 // the block are reexported in dylib build of std. This is needed when build rustc with
 // feature `llvm-libunwind`, as no other cdylib will provided those _Unwind_* symbols.
@@ -110,10 +53,10 @@ cfg_select! {
         pub type _Unwind_Action = c_int;
 
         pub const _UA_SEARCH_PHASE: c_int = 1;
-        pub const _UA_CLEANUP_PHASE: c_int = 2;
-        pub const _UA_HANDLER_FRAME: c_int = 4;
+        //pub const _UA_CLEANUP_PHASE: c_int = 2;
+        //pub const _UA_HANDLER_FRAME: c_int = 4;
         pub const _UA_FORCE_UNWIND: c_int = 8;
-        pub const _UA_END_OF_STACK: c_int = 16;
+        //pub const _UA_END_OF_STACK: c_int = 16;
 
         #[cfg_attr(
             all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
@@ -122,11 +65,9 @@ cfg_select! {
         unsafe extern "C" {
             pub fn _Unwind_GetGR(ctx: *mut _Unwind_Context, reg_index: c_int) -> _Unwind_Word;
             pub fn _Unwind_SetGR(ctx: *mut _Unwind_Context, reg_index: c_int, value: _Unwind_Word);
-            pub fn _Unwind_GetIP(ctx: *mut _Unwind_Context) -> _Unwind_Word;
             pub fn _Unwind_SetIP(ctx: *mut _Unwind_Context, value: _Unwind_Word);
             pub fn _Unwind_GetIPInfo(ctx: *mut _Unwind_Context, ip_before_insn: *mut c_int)
                                      -> _Unwind_Word;
-            pub fn _Unwind_FindEnclosingFunction(pc: *mut c_void) -> *mut c_void;
         }
 
     }
@@ -213,12 +154,6 @@ cfg_select! {
                             (&raw mut value) as *mut c_void); }
         }
 
-        pub unsafe fn _Unwind_GetIP(ctx: *mut _Unwind_Context)
-                                    -> _Unwind_Word {
-            let val = unsafe { _Unwind_GetGR(ctx, UNWIND_IP_REG) };
-            val.map_addr(|v| v & !1)
-        }
-
         pub unsafe fn _Unwind_SetIP(ctx: *mut _Unwind_Context,
                                     value: _Unwind_Word) {
             // Propagate thumb bit to instruction pointer
@@ -232,45 +167,24 @@ cfg_select! {
                                         -> _Unwind_Word {
             unsafe {
                 *ip_before_insn = 0;
-                _Unwind_GetIP(ctx)
+                let val = unsafe { _Unwind_GetGR(ctx, UNWIND_IP_REG) };
+                val.map_addr(|v| v & !1)
             }
         }
-
-        // This function also doesn't exist on Android or ARM/Linux, so make it a no-op
-        pub unsafe fn _Unwind_FindEnclosingFunction(pc: *mut c_void) -> *mut c_void {
-            pc
-        }
     }
 }
 
-cfg_select! {
-    all(target_vendor = "apple", not(target_os = "watchos"), target_arch = "arm") => {
-        // 32-bit ARM Apple (except for watchOS armv7k specifically) uses SjLj and
-        // does not provide _Unwind_Backtrace()
-        unsafe extern "C-unwind" {
-            pub fn _Unwind_SjLj_RaiseException(e: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
-        }
-
-        pub use _Unwind_SjLj_RaiseException as _Unwind_RaiseException;
-    }
-    _ => {
-        #[cfg_attr(
-            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")),
-            link(name = "unwind", kind = "static", modifiers = "-bundle")
-        )]
-        unsafe extern "C" {
-            pub fn _Unwind_Backtrace(trace: _Unwind_Trace_Fn,
-                                     trace_argument: *mut c_void)
-                                     -> _Unwind_Reason_Code;
-        }
-    }
+#[cfg_attr(
+    all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
+    link(name = "unwind", kind = "static", modifiers = "-bundle")
+)]
+unsafe extern "C-unwind" {
+    // 32-bit ARM Apple (except for watchOS armv7k specifically) uses SjLj
+    #[cfg_attr(
+        all(target_vendor = "apple", not(target_os = "watchos"), target_arch = "arm"),
+        link_name = "_Unwind_SjLj_RaiseException"
+    )]
+    pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
 }
 
 cfg_select! {

library/unwind/src/libunwind.rs

@@ -0,0 +1,59 @@
+#![allow(nonstandard_style)]
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum _Unwind_Reason_Code {
+    _URC_NO_REASON = 0,
+    _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
+    _URC_FATAL_PHASE2_ERROR = 2,
+    _URC_FATAL_PHASE1_ERROR = 3,
+    _URC_NORMAL_STOP = 4,
+    _URC_END_OF_STACK = 5,
+    _URC_HANDLER_FOUND = 6,
+    _URC_INSTALL_CONTEXT = 7,
+    _URC_CONTINUE_UNWIND = 8,
+    _URC_FAILURE = 9, // used only by ARM EHABI
+}
+pub use _Unwind_Reason_Code::*;
+
+pub type _Unwind_Exception_Class = u64;
+pub type _Unwind_Word = *const u8;
+
+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,
+    target_family = "wasm" => 2,
+    target_arch = "hexagon" => 5,
+    any(target_arch = "loongarch32", target_arch = "loongarch64") => 2,
+};
+
+#[repr(C)]
+pub struct _Unwind_Exception {
+    pub exception_class: _Unwind_Exception_Class,
+    pub exception_cleanup: _Unwind_Exception_Cleanup_Fn,
+    pub private: [_Unwind_Word; unwinder_private_data_size],
+}
+
+// Check the size of _Unwind_Exception against the source of truth when using the unwinding crate.
+#[cfg(target_os = "xous")]
+const _: () = {
+    assert!(size_of::<unwinding::abi::UnwindException>() == size_of::<_Unwind_Exception>());
+};
+
+pub type _Unwind_Exception_Cleanup_Fn =
+    Option<extern "C" fn(unwind_code: _Unwind_Reason_Code, exception: *mut _Unwind_Exception)>;

library/unwind/src/types.rs

@@ -26,36 +26,7 @@ core::arch::global_asm!(
     "__cpp_exception:",
 );
 
-#[repr(C)]
-#[derive(Debug, Copy, Clone, PartialEq)]
-pub enum _Unwind_Reason_Code {
-    _URC_NO_REASON = 0,
-    _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
-    _URC_FATAL_PHASE2_ERROR = 2,
-    _URC_FATAL_PHASE1_ERROR = 3,
-    _URC_NORMAL_STOP = 4,
-    _URC_END_OF_STACK = 5,
-    _URC_HANDLER_FOUND = 6,
-    _URC_INSTALL_CONTEXT = 7,
-    _URC_CONTINUE_UNWIND = 8,
-    _URC_FAILURE = 9, // used only by ARM EHABI
-}
-pub use _Unwind_Reason_Code::*;
-
-pub type _Unwind_Exception_Class = u64;
-pub type _Unwind_Word = *const u8;
-
-pub const unwinder_private_data_size: usize = 2;
-
-#[repr(C)]
-pub struct _Unwind_Exception {
-    pub exception_class: _Unwind_Exception_Class,
-    pub exception_cleanup: _Unwind_Exception_Cleanup_Fn,
-    pub private: [_Unwind_Word; unwinder_private_data_size],
-}
-
-pub type _Unwind_Exception_Cleanup_Fn =
-    Option<extern "C" fn(unwind_code: _Unwind_Reason_Code, exception: *mut _Unwind_Exception)>;
+pub use crate::types::*;
 
 pub unsafe fn _Unwind_DeleteException(exception: *mut _Unwind_Exception) {
     if let Some(exception_cleanup) = unsafe { (*exception).exception_cleanup } {