Special case Rust unwind terminate for forced unwind

This changes the personality to match the current libstd impl.

src/personality.rs

@@ -16,6 +16,8 @@ enum EHAction {
  None,
  Cleanup(usize),
  Catch(usize),
+ Filter(usize),
+ Terminate,
 }
 
 fn parse_pointer_encoding(input: &mut StaticSlice) -> gimli::Result<constants::DwEhPe> {
@@ -92,31 +94,31 @@ fn find_eh_action(
 
  let call_site_encoding = parse_pointer_encoding(reader)?;
  let call_site_table_length = reader.read_uleb128()?;
- reader.truncate(call_site_table_length as _)?;
+ let (mut call_site_table, mut action_table) = reader.split_at(call_site_table_length as _);
 
- while !reader.is_empty() {
+ while !call_site_table.is_empty() {
  let cs_start = unsafe {
  deref_pointer(parse_encoded_pointer(
  call_site_encoding,
  unwind_ctx,
- reader,
+ &mut call_site_table,
  )?)
  };
  let cs_len = unsafe {
  deref_pointer(parse_encoded_pointer(
  call_site_encoding,
  unwind_ctx,
- reader,
+ &mut call_site_table,
  )?)
  };
  let cs_lpad = unsafe {
  deref_pointer(parse_encoded_pointer(
  call_site_encoding,
  unwind_ctx,
- reader,
+ &mut call_site_table,
  )?)
  };
- let cs_action = reader.read_uleb128()?;
+ let cs_action = call_site_table.read_uleb128()?;
  if ip < func_start + cs_start {
  break;
  }
@@ -125,14 +127,23 @@ fn find_eh_action(
  return Ok(EHAction::None);
  } else {
  let lpad = lpad_base + cs_lpad;
- return Ok(match cs_action {
- 0 => EHAction::Cleanup(lpad),
- _ => EHAction::Catch(lpad),
+ if cs_action == 0 {
+ return Ok(EHAction::Cleanup(lpad));
+ }
+
+ action_table.skip((cs_action - 1) as _)?;
+ let ttype_index = action_table.read_sleb128()?;
+ return Ok(if ttype_index == 0 {
+ EHAction::Cleanup(lpad)
+ } else if ttype_index > 0 {
+ EHAction::Catch(lpad)
+ } else {
+ EHAction::Filter(lpad)
  });
  }
  }
  }
- Ok(EHAction::None)
+ Ok(EHAction::Terminate)
 }
 
 #[lang = "eh_personality"]
@@ -161,12 +172,17 @@ unsafe fn rust_eh_personality(
  if actions.contains(UnwindAction::SEARCH_PHASE) {
  match eh_action {
  EHAction::None | EHAction::Cleanup(_) => UnwindReasonCode::CONTINUE_UNWIND,
- EHAction::Catch(_) => UnwindReasonCode::HANDLER_FOUND,
+ EHAction::Catch(_) | EHAction::Filter(_) => UnwindReasonCode::HANDLER_FOUND,
+ EHAction::Terminate => UnwindReasonCode::FATAL_PHASE1_ERROR,
  }
  } else {
  match eh_action {
  EHAction::None => UnwindReasonCode::CONTINUE_UNWIND,
- EHAction::Cleanup(lpad) | EHAction::Catch(lpad) => {
+ // Forced unwinding hits a terminate action.
+ EHAction::Filter(_) if actions.contains(UnwindAction::FORCE_UNWIND) => {
+ UnwindReasonCode::CONTINUE_UNWIND
+ }
+ EHAction::Cleanup(lpad) | EHAction::Catch(lpad) | EHAction::Filter(lpad) => {
  _Unwind_SetGR(
  unwind_ctx,
  Arch::UNWIND_DATA_REG.0 .0 as _,
@@ -176,6 +192,7 @@ unsafe fn rust_eh_personality(
  _Unwind_SetIP(unwind_ctx, lpad);
  UnwindReasonCode::INSTALL_CONTEXT
  }
+ EHAction::Terminate => UnwindReasonCode::FATAL_PHASE2_ERROR,
  }
  }
 }