summaryrefslogtreecommitdiffstats
path: root/library/std/src/personality/dwarf/eh.rs
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-30 03:59:35 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-30 03:59:35 +0000
commitd1b2d29528b7794b41e66fc2136e395a02f8529b (patch)
treea4a17504b260206dec3cf55b2dca82929a348ac2 /library/std/src/personality/dwarf/eh.rs
parentReleasing progress-linux version 1.72.1+dfsg1-1~progress7.99u1. (diff)
downloadrustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.tar.xz
rustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.zip
Merging upstream version 1.73.0+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/std/src/personality/dwarf/eh.rs')
-rw-r--r--library/std/src/personality/dwarf/eh.rs208
1 files changed, 0 insertions, 208 deletions
diff --git a/library/std/src/personality/dwarf/eh.rs b/library/std/src/personality/dwarf/eh.rs
deleted file mode 100644
index 79624703a..000000000
--- a/library/std/src/personality/dwarf/eh.rs
+++ /dev/null
@@ -1,208 +0,0 @@
-//! Parsing of GCC-style Language-Specific Data Area (LSDA)
-//! For details see:
-//! * <https://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-PDA/LSB-PDA/ehframechpt.html>
-//! * <https://itanium-cxx-abi.github.io/cxx-abi/exceptions.pdf>
-//! * <https://www.airs.com/blog/archives/460>
-//! * <https://www.airs.com/blog/archives/464>
-//!
-//! A reference implementation may be found in the GCC source tree
-//! (`<root>/libgcc/unwind-c.c` as of this writing).
-
-#![allow(non_upper_case_globals)]
-#![allow(unused)]
-
-use super::DwarfReader;
-use core::mem;
-use core::ptr;
-
-pub const DW_EH_PE_omit: u8 = 0xFF;
-pub const DW_EH_PE_absptr: u8 = 0x00;
-
-pub const DW_EH_PE_uleb128: u8 = 0x01;
-pub const DW_EH_PE_udata2: u8 = 0x02;
-pub const DW_EH_PE_udata4: u8 = 0x03;
-pub const DW_EH_PE_udata8: u8 = 0x04;
-pub const DW_EH_PE_sleb128: u8 = 0x09;
-pub const DW_EH_PE_sdata2: u8 = 0x0A;
-pub const DW_EH_PE_sdata4: u8 = 0x0B;
-pub const DW_EH_PE_sdata8: u8 = 0x0C;
-
-pub const DW_EH_PE_pcrel: u8 = 0x10;
-pub const DW_EH_PE_textrel: u8 = 0x20;
-pub const DW_EH_PE_datarel: u8 = 0x30;
-pub const DW_EH_PE_funcrel: u8 = 0x40;
-pub const DW_EH_PE_aligned: u8 = 0x50;
-
-pub const DW_EH_PE_indirect: u8 = 0x80;
-
-#[derive(Copy, Clone)]
-pub struct EHContext<'a> {
- pub ip: usize, // Current instruction pointer
- pub func_start: usize, // Address of the current function
- pub get_text_start: &'a dyn Fn() -> usize, // Get address of the code section
- pub get_data_start: &'a dyn Fn() -> usize, // Get address of the data section
-}
-
-pub enum EHAction {
- None,
- Cleanup(usize),
- Catch(usize),
- Filter(usize),
- Terminate,
-}
-
-pub const USING_SJLJ_EXCEPTIONS: bool = cfg!(all(target_os = "ios", target_arch = "arm"));
-
-pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>) -> Result<EHAction, ()> {
- if lsda.is_null() {
- return Ok(EHAction::None);
- }
-
- let func_start = context.func_start;
- let mut reader = DwarfReader::new(lsda);
-
- let start_encoding = reader.read::<u8>();
- // base address for landing pad offsets
- let lpad_base = if start_encoding != DW_EH_PE_omit {
- read_encoded_pointer(&mut reader, context, start_encoding)?
- } else {
- func_start
- };
-
- let ttype_encoding = reader.read::<u8>();
- if ttype_encoding != DW_EH_PE_omit {
- // Rust doesn't analyze exception types, so we don't care about the type table
- reader.read_uleb128();
- }
-
- let call_site_encoding = reader.read::<u8>();
- let call_site_table_length = reader.read_uleb128();
- let action_table = reader.ptr.add(call_site_table_length as usize);
- let ip = context.ip;
-
- if !USING_SJLJ_EXCEPTIONS {
- while reader.ptr < action_table {
- let cs_start = read_encoded_pointer(&mut reader, context, call_site_encoding)?;
- let cs_len = read_encoded_pointer(&mut reader, context, call_site_encoding)?;
- let cs_lpad = read_encoded_pointer(&mut reader, context, call_site_encoding)?;
- let cs_action_entry = reader.read_uleb128();
- // Callsite table is sorted by cs_start, so if we've passed the ip, we
- // may stop searching.
- if ip < func_start + cs_start {
- break;
- }
- if ip < func_start + cs_start + cs_len {
- if cs_lpad == 0 {
- return Ok(EHAction::None);
- } else {
- let lpad = lpad_base + cs_lpad;
- return Ok(interpret_cs_action(action_table as *mut u8, cs_action_entry, lpad));
- }
- }
- }
- // Ip is not present in the table. This indicates a nounwind call.
- Ok(EHAction::Terminate)
- } else {
- // SjLj version:
- // The "IP" is an index into the call-site table, with two exceptions:
- // -1 means 'no-action', and 0 means 'terminate'.
- match ip as isize {
- -1 => return Ok(EHAction::None),
- 0 => return Ok(EHAction::Terminate),
- _ => (),
- }
- let mut idx = ip;
- loop {
- let cs_lpad = reader.read_uleb128();
- let cs_action_entry = reader.read_uleb128();
- idx -= 1;
- if idx == 0 {
- // Can never have null landing pad for sjlj -- that would have
- // been indicated by a -1 call site index.
- let lpad = (cs_lpad + 1) as usize;
- return Ok(interpret_cs_action(action_table as *mut u8, cs_action_entry, lpad));
- }
- }
- }
-}
-
-unsafe fn interpret_cs_action(
- action_table: *mut u8,
- cs_action_entry: u64,
- lpad: usize,
-) -> EHAction {
- if cs_action_entry == 0 {
- // If cs_action_entry is 0 then this is a cleanup (Drop::drop). We run these
- // for both Rust panics and foreign exceptions.
- EHAction::Cleanup(lpad)
- } else {
- // If lpad != 0 and cs_action_entry != 0, we have to check ttype_index.
- // If ttype_index == 0 under the condition, we take cleanup action.
- let action_record = (action_table as *mut u8).offset(cs_action_entry as isize - 1);
- let mut action_reader = DwarfReader::new(action_record);
- let ttype_index = action_reader.read_sleb128();
- if ttype_index == 0 {
- EHAction::Cleanup(lpad)
- } else if ttype_index > 0 {
- // Stop unwinding Rust panics at catch_unwind.
- EHAction::Catch(lpad)
- } else {
- EHAction::Filter(lpad)
- }
- }
-}
-
-#[inline]
-fn round_up(unrounded: usize, align: usize) -> Result<usize, ()> {
- if align.is_power_of_two() { Ok((unrounded + align - 1) & !(align - 1)) } else { Err(()) }
-}
-
-unsafe fn read_encoded_pointer(
- reader: &mut DwarfReader,
- context: &EHContext<'_>,
- encoding: u8,
-) -> Result<usize, ()> {
- if encoding == DW_EH_PE_omit {
- return Err(());
- }
-
- // DW_EH_PE_aligned implies it's an absolute pointer value
- if encoding == DW_EH_PE_aligned {
- reader.ptr = reader.ptr.with_addr(round_up(reader.ptr.addr(), mem::size_of::<usize>())?);
- return Ok(reader.read::<usize>());
- }
-
- let mut result = match encoding & 0x0F {
- DW_EH_PE_absptr => reader.read::<usize>(),
- DW_EH_PE_uleb128 => reader.read_uleb128() as usize,
- DW_EH_PE_udata2 => reader.read::<u16>() as usize,
- DW_EH_PE_udata4 => reader.read::<u32>() as usize,
- DW_EH_PE_udata8 => reader.read::<u64>() as usize,
- DW_EH_PE_sleb128 => reader.read_sleb128() as usize,
- DW_EH_PE_sdata2 => reader.read::<i16>() as usize,
- DW_EH_PE_sdata4 => reader.read::<i32>() as usize,
- DW_EH_PE_sdata8 => reader.read::<i64>() as usize,
- _ => return Err(()),
- };
-
- result += match encoding & 0x70 {
- DW_EH_PE_absptr => 0,
- // relative to address of the encoded value, despite the name
- DW_EH_PE_pcrel => reader.ptr.expose_addr(),
- DW_EH_PE_funcrel => {
- if context.func_start == 0 {
- return Err(());
- }
- context.func_start
- }
- DW_EH_PE_textrel => (*context.get_text_start)(),
- DW_EH_PE_datarel => (*context.get_data_start)(),
- _ => return Err(()),
- };
-
- if encoding & DW_EH_PE_indirect != 0 {
- result = *ptr::from_exposed_addr::<usize>(result);
- }
-
- Ok(result)
-}