bjoernager/rust
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Remove custom frame info registration on i686-pc-windows-gnu

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The indirection is no longer needed since we always link to libgcc
even when the panic_abort runtime is used. Instead we can just call
the libgcc functions directly.
This commit is contained in:
Amanieu d'Antras 2022-02-09 14:16:57 +00:00
parent 5ff0876694
commit c110329f25
4 changed files with 14 additions and 51 deletions
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9
library/panic_abort/src/lib.rs
View file

@ -123,13 +123,4 @@ pub mod personalities {
#[allow(non_upper_case_globals)] #[allow(non_upper_case_globals)]
#[cfg(target_os = "emscripten")] #[cfg(target_os = "emscripten")]
static rust_eh_catch_typeinfo: [usize; 2] = [0; 2]; static rust_eh_catch_typeinfo: [usize; 2] = [0; 2];
// These two are called by our startup objects on i686-pc-windows-gnu, but
// they don't need to do anything so the bodies are nops.
#[rustc_std_internal_symbol]
#[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
pub extern "C" fn rust_eh_register_frames() {}
#[rustc_std_internal_symbol]
#[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
pub extern "C" fn rust_eh_unregister_frames() {}
} }

34
library/panic_unwind/src/gcc.rs
View file

@ -87,37 +87,3 @@ fn rust_exception_class() -> uw::_Unwind_Exception_Class {
// M O Z \0 R U S T -- vendor, language // M O Z \0 R U S T -- vendor, language
0x4d4f5a_00_52555354 0x4d4f5a_00_52555354
} }
// Frame unwind info registration
//
// Each module's image contains a frame unwind info section (usually
// ".eh_frame"). When a module is loaded/unloaded into the process, the
// unwinder must be informed about the location of this section in memory. The
// methods of achieving that vary by the platform. On some (e.g., Linux), the
// unwinder can discover unwind info sections on its own (by dynamically
// enumerating currently loaded modules via the dl_iterate_phdr() API and
// finding their ".eh_frame" sections); Others, like Windows, require modules
// to actively register their unwind info sections via unwinder API.
//
// This module defines two symbols which are referenced and called from
// rsbegin.rs to register our information with the GCC runtime. The
// implementation of stack unwinding is (for now) deferred to libgcc_eh, however
// Rust crates use these Rust-specific entry points to avoid potential clashes
// with any GCC runtime.
#[cfg(all(target_os = "windows", target_arch = "x86", target_env = "gnu"))]
pub mod eh_frame_registry {
extern "C" {
fn __register_frame_info(eh_frame_begin: *const u8, object: *mut u8);
fn __deregister_frame_info(eh_frame_begin: *const u8, object: *mut u8);
}
#[rustc_std_internal_symbol]
pub unsafe extern "C" fn rust_eh_register_frames(eh_frame_begin: *const u8, object: *mut u8) {
__register_frame_info(eh_frame_begin, object);
}
#[rustc_std_internal_symbol]
pub unsafe extern "C" fn rust_eh_unregister_frames(eh_frame_begin: *const u8, object: *mut u8) {
__deregister_frame_info(eh_frame_begin, object);
}
}

3
library/panic_unwind/src/lib.rs
View file

@ -52,9 +52,6 @@ cfg_if::cfg_if! {
all(target_family = "unix", not(target_os = "espidf")), all(target_family = "unix", not(target_os = "espidf")),
all(target_vendor = "fortanix", target_env = "sgx"), all(target_vendor = "fortanix", target_env = "sgx"),
))] { ))] {
// Rust runtime's startup objects depend on these symbols, so make them public.
#[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))]
pub use real_imp::eh_frame_registry::*;
#[path = "gcc.rs"] #[path = "gcc.rs"]
mod real_imp; mod real_imp;
} else { } else {

19
library/rtstartup/rsbegin.rs
View file

@ -35,6 +35,16 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
drop_in_place(to_drop); drop_in_place(to_drop);
} }
// Frame unwind info registration
//
// Each module's image contains a frame unwind info section (usually
// ".eh_frame"). When a module is loaded/unloaded into the process, the
// unwinder must be informed about the location of this section in memory. The
// methods of achieving that vary by the platform. On some (e.g., Linux), the
// unwinder can discover unwind info sections on its own (by dynamically
// enumerating currently loaded modules via the dl_iterate_phdr() API and
// finding their ".eh_frame" sections); Others, like Windows, require modules
// to actively register their unwind info sections via unwinder API.
#[cfg(all(target_os = "windows", target_arch = "x86", target_env = "gnu"))] #[cfg(all(target_os = "windows", target_arch = "x86", target_env = "gnu"))]
pub mod eh_frames { pub mod eh_frames {
#[no_mangle] #[no_mangle]
@ -62,20 +72,19 @@ pub mod eh_frames {
} }
// Unwind info registration/deregistration routines. // Unwind info registration/deregistration routines.
// See the docs of libpanic_unwind.
extern "C" { extern "C" {
fn rust_eh_register_frames(eh_frame_begin: *const u8, object: *mut u8); fn __register_frame_info(eh_frame_begin: *const u8, object: *mut u8);
fn rust_eh_unregister_frames(eh_frame_begin: *const u8, object: *mut u8); fn __deregister_frame_info(eh_frame_begin: *const u8, object: *mut u8);
} }
unsafe extern "C" fn init() { unsafe extern "C" fn init() {
// register unwind info on module startup // register unwind info on module startup
rust_eh_register_frames(&__EH_FRAME_BEGIN__ as *const u8, &mut OBJ as *mut _ as *mut u8); __register_frame_info(&__EH_FRAME_BEGIN__ as *const u8, &mut OBJ as *mut _ as *mut u8);
} }
unsafe extern "C" fn uninit() { unsafe extern "C" fn uninit() {
// unregister on shutdown // unregister on shutdown
rust_eh_unregister_frames(&__EH_FRAME_BEGIN__ as *const u8, &mut OBJ as *mut _ as *mut u8); __deregister_frame_info(&__EH_FRAME_BEGIN__ as *const u8, &mut OBJ as *mut _ as *mut u8);
} }
// MinGW-specific init/uninit routine registration // MinGW-specific init/uninit routine registration