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#![allow(non_upper_case_globals)]
#![allow(unused)]
use prelude::v1::*;
use rt::dwarf::DwarfReader;
use core::mem;
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 {
pub ip: usize,
pub func_start: usize,
pub text_start: usize,
pub data_start: usize,
}
pub unsafe fn find_landing_pad(lsda: *const u8, context: &EHContext)
-> Option<usize> {
if lsda.is_null() {
return None;
}
let func_start = context.func_start;
let mut reader = DwarfReader::new(lsda);
let start_encoding = reader.read::<u8>();
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 {
reader.read_uleb128();
}
let call_site_encoding = reader.read::<u8>();
let call_site_table_length = reader.read_uleb128();
let action_table = reader.ptr.offset(call_site_table_length as isize);
let ip = context.ip-1;
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 = reader.read_uleb128();
if ip < func_start + cs_start {
break
}
if ip < func_start + cs_start + cs_len {
if cs_lpad != 0 {
return Some(lpad_base + cs_lpad);
} else {
return None;
}
}
}
return None;
}
#[inline]
fn round_up(unrounded: usize, align: usize) -> usize {
assert!(align.is_power_of_two());
(unrounded + align - 1) & !(align - 1)
}
unsafe fn read_encoded_pointer(reader: &mut DwarfReader,
context: &EHContext,
encoding: u8) -> usize {
assert!(encoding != DW_EH_PE_omit);
if encoding == DW_EH_PE_aligned {
reader.ptr = round_up(reader.ptr as usize,
mem::size_of::<usize>()) as *const u8;
return 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,
_ => panic!()
};
result += match encoding & 0x70 {
DW_EH_PE_absptr => 0,
DW_EH_PE_pcrel => reader.ptr as usize,
DW_EH_PE_textrel => { assert!(context.text_start != 0);
context.text_start },
DW_EH_PE_datarel => { assert!(context.data_start != 0);
context.data_start },
DW_EH_PE_funcrel => { assert!(context.func_start != 0);
context.func_start },
_ => panic!()
};
if encoding & DW_EH_PE_indirect != 0 {
result = *(result as *const usize);
}
result
}