use cranelift_codegen::isa::{unwind::UnwindInfo, TargetIsa};
use gimli::write::{Address, CieId, EhFrame, FrameTable, Section};
+use gimli::RunTimeEndian;
use crate::backend::WriteDebugInfo;
-pub(crate) struct UnwindContext<'tcx> {
- tcx: TyCtxt<'tcx>,
+pub(crate) struct UnwindContext {
+ endian: RunTimeEndian,
frame_table: FrameTable,
cie_id: Option<CieId>,
}
-impl<'tcx> UnwindContext<'tcx> {
- pub(crate) fn new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa, pic_eh_frame: bool) -> Self {
+impl UnwindContext {
+ pub(crate) fn new(tcx: TyCtxt<'_>, isa: &dyn TargetIsa, pic_eh_frame: bool) -> Self {
+ let endian = super::target_endian(tcx);
let mut frame_table = FrameTable::default();
let cie_id = if let Some(mut cie) = isa.create_systemv_cie() {
None
};
- UnwindContext { tcx, frame_table, cie_id }
+ UnwindContext { endian, frame_table, cie_id }
}
pub(crate) fn add_function(&mut self, func_id: FuncId, context: &Context, isa: &dyn TargetIsa) {
}
pub(crate) fn emit<P: WriteDebugInfo>(self, product: &mut P) {
- let mut eh_frame =
- EhFrame::from(super::emit::WriterRelocate::new(super::target_endian(self.tcx)));
+ let mut eh_frame = EhFrame::from(super::emit::WriterRelocate::new(self.endian));
self.frame_table.write_eh_frame(&mut eh_frame).unwrap();
if !eh_frame.0.writer.slice().is_empty() {
}
#[cfg(feature = "jit")]
- pub(crate) unsafe fn register_jit(
- self,
- jit_module: &cranelift_jit::JITModule,
- ) -> Option<UnwindRegistry> {
- let mut eh_frame =
- EhFrame::from(super::emit::WriterRelocate::new(super::target_endian(self.tcx)));
+ pub(crate) unsafe fn register_jit(self, jit_module: &cranelift_jit::JITModule) {
+ let mut eh_frame = EhFrame::from(super::emit::WriterRelocate::new(self.endian));
self.frame_table.write_eh_frame(&mut eh_frame).unwrap();
if eh_frame.0.writer.slice().is_empty() {
- return None;
+ return;
}
let mut eh_frame = eh_frame.0.relocate_for_jit(jit_module);
// GCC expects a terminating "empty" length, so write a 0 length at the end of the table.
eh_frame.extend(&[0, 0, 0, 0]);
- let mut registrations = Vec::new();
+ // FIXME support unregistering unwind tables once cranelift-jit supports deallocating
+ // individual functions
+ #[allow(unused_variables)]
+ let (eh_frame, eh_frame_len, _) = Vec::into_raw_parts(eh_frame);
// =======================================================================
// Everything after this line up to the end of the file is loosly based on
#[cfg(target_os = "macos")]
{
// On macOS, `__register_frame` takes a pointer to a single FDE
- let start = eh_frame.as_ptr();
- let end = start.add(eh_frame.len());
+ let start = eh_frame;
+ let end = start.add(eh_frame_len);
let mut current = start;
// Walk all of the entries in the frame table and register them
// Skip over the CIE
if current != start {
__register_frame(current);
- registrations.push(current as usize);
}
// Move to the next table entry (+4 because the length itself is not inclusive)
#[cfg(not(target_os = "macos"))]
{
// On other platforms, `__register_frame` will walk the FDEs until an entry of length 0
- let ptr = eh_frame.as_ptr();
- __register_frame(ptr);
- registrations.push(ptr as usize);
+ __register_frame(eh_frame);
}
-
- Some(UnwindRegistry { _frame_table: eh_frame, registrations })
}
}
-/// Represents a registry of function unwind information for System V ABI.
-pub(crate) struct UnwindRegistry {
- _frame_table: Vec<u8>,
- registrations: Vec<usize>,
-}
-
extern "C" {
// libunwind import
fn __register_frame(fde: *const u8);
- fn __deregister_frame(fde: *const u8);
-}
-
-impl Drop for UnwindRegistry {
- fn drop(&mut self) {
- unsafe {
- // libgcc stores the frame entries as a linked list in decreasing sort order
- // based on the PC value of the registered entry.
- //
- // As we store the registrations in increasing order, it would be O(N^2) to
- // deregister in that order.
- //
- // To ensure that we just pop off the first element in the list upon every
- // deregistration, walk our list of registrations backwards.
- for fde in self.registrations.iter().rev() {
- __deregister_frame(*fde as *const _);
- }
- }
- }
}