std/sys/personality/dwarf/
mod.rs

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1//! Utilities for parsing DWARF-encoded data streams.
2//! See <http://www.dwarfstd.org>,
3//! DWARF-4 standard, Section 7 - "Data Representation"
4
5// This module is used only by x86_64-pc-windows-gnu for now, but we
6// are compiling it everywhere to avoid regressions.
7#![allow(unused)]
8#![forbid(unsafe_op_in_unsafe_fn)]
9
10#[cfg(test)]
11mod tests;
12
13pub mod eh;
14
15pub struct DwarfReader {
16    pub ptr: *const u8,
17}
18
19impl DwarfReader {
20    pub fn new(ptr: *const u8) -> DwarfReader {
21        DwarfReader { ptr }
22    }
23
24    /// Read a type T and then bump the pointer by that amount.
25    ///
26    /// DWARF streams are "packed", so all types must be read at align 1.
27    pub unsafe fn read<T: Copy>(&mut self) -> T {
28        unsafe {
29            let result = self.ptr.cast::<T>().read_unaligned();
30            self.ptr = self.ptr.byte_add(size_of::<T>());
31            result
32        }
33    }
34
35    /// ULEB128 and SLEB128 encodings are defined in Section 7.6 - "Variable Length Data".
36    pub unsafe fn read_uleb128(&mut self) -> u64 {
37        let mut shift: usize = 0;
38        let mut result: u64 = 0;
39        let mut byte: u8;
40        loop {
41            byte = unsafe { self.read::<u8>() };
42            result |= ((byte & 0x7F) as u64) << shift;
43            shift += 7;
44            if byte & 0x80 == 0 {
45                break;
46            }
47        }
48        result
49    }
50
51    pub unsafe fn read_sleb128(&mut self) -> i64 {
52        let mut shift: u32 = 0;
53        let mut result: u64 = 0;
54        let mut byte: u8;
55        loop {
56            byte = unsafe { self.read::<u8>() };
57            result |= ((byte & 0x7F) as u64) << shift;
58            shift += 7;
59            if byte & 0x80 == 0 {
60                break;
61            }
62        }
63        // sign-extend
64        if shift < u64::BITS && (byte & 0x40) != 0 {
65            result |= (!0 as u64) << shift;
66        }
67        result as i64
68    }
69}
std/sys/personality/dwarf/mod.rs

std/sys/personality/dwarf/
mod.rs
