Use a global_asm! instead of a naked function

Author: Amanieu

src/libpanic_unwind/gcc.rs

@@ -326,22 +326,38 @@ unsafe fn find_eh_action(
 
 // See docs in the `unwind` module.
 #[cfg(all(
+    not(bootstrap),
+    target_os = "windows",
+    any(target_arch = "x86", target_arch = "x86_64"),
+    target_env = "gnu"
+))]
+global_asm! {
+    r#"
+    .def _rust_eh_unwind_resume;
+    .scl 2;
+    .type 32;
+    .endef
+    .globl _rust_eh_unwind_resume
+    .p2align 4, 0x90
+_rust_eh_unwind_resume:
+    .cfi_startproc
+    jmp __Unwind_Resume
+    .cfi_endproc
+    "#
+}
+#[cfg(all(
+    bootstrap,
     target_os = "windows",
     any(target_arch = "x86", target_arch = "x86_64"),
     target_env = "gnu"
 ))]
 #[lang = "eh_unwind_resume"]
 #[unwind(allowed)]
-#[naked]
-#[inline(never)]
-unsafe extern "C" fn rust_eh_unwind_resume(_panic_ctx: *mut u8) -> ! {
-    // This needs to be a naked function because _Unwind_Resume expects to be
-    // called directly from the landing pad. This means that we need to force
-    // a tail call here.
-    asm!("jmp ${0:P}" :: "s" (uw::_Unwind_Resume as usize) :: "volatile");
-    core::hint::unreachable_unchecked();
+unsafe extern "C" fn rust_eh_unwind_resume(panic_ctx: *mut u8) -> ! {
+    uw::_Unwind_Resume(panic_ctx as *mut uw::_Unwind_Exception);
 }
 
+
 // Frame unwind info registration
 //
 // Each module's image contains a frame unwind info section (usually

src/libpanic_unwind/lib.rs

@@ -32,6 +32,7 @@
 #![feature(naked_functions)]
 #![panic_runtime]
 #![feature(panic_runtime)]
+#![feature(global_asm)]
 
 use alloc::boxed::Box;
 use core::any::Any;