1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128

use crate::common::{DebugAddrBase, DebugAddrIndex, SectionId};
use crate::read::{Reader, ReaderOffset, Result, Section};

/// The raw contents of the `.debug_addr` section.
#[derive(Debug, Default, Clone, Copy)]
pub struct DebugAddr<R> {
    section: R,
}

impl<R: Reader> DebugAddr<R> {
    // TODO: add an iterator over the sets of addresses in the section.
    // This is not needed for common usage of the section though.

    /// Returns the address at the given `base` and `index`.
    ///
    /// A set of addresses in the `.debug_addr` section consists of a header
    /// followed by a series of addresses.
    ///
    /// The `base` must be the `DW_AT_addr_base` value from the compilation unit DIE.
    /// This is an offset that points to the first address following the header.
    ///
    /// The `index` is the value of a `DW_FORM_addrx` attribute.
    ///
    /// The `address_size` must be the size of the address for the compilation unit.
    /// This value must also match the header. However, note that we do not parse the
    /// header to validate this, since locating the header is unreliable, and the GNU
    /// extensions do not emit it.
    pub fn get_address(
        &self,
        address_size: u8,
        base: DebugAddrBase<R::Offset>,
        index: DebugAddrIndex<R::Offset>,
    ) -> Result<u64> {
        let input = &mut self.section.clone();
        input.skip(base.0)?;
        input.skip(R::Offset::from_u64(
            index.0.into_u64() * u64::from(address_size),
        )?)?;
        input.read_address(address_size)
    }
}

impl<T> DebugAddr<T> {
    /// Create a `DebugAddr` section that references the data in `self`.
    ///
    /// This is useful when `R` implements `Reader` but `T` does not.
    ///
    /// ## Example Usage
    ///
    /// ```rust,no_run
    /// # let load_section = || unimplemented!();
    /// // Read the DWARF section into a `Vec` with whatever object loader you're using.
    /// let owned_section: gimli::DebugAddr<Vec<u8>> = load_section();
    /// // Create a reference to the DWARF section.
    /// let section = owned_section.borrow(|section| {
    ///     gimli::EndianSlice::new(&section, gimli::LittleEndian)
    /// });
    /// ```
    pub fn borrow<'a, F, R>(&'a self, mut borrow: F) -> DebugAddr<R>
    where
        F: FnMut(&'a T) -> R,
    {
        borrow(&self.section).into()
    }
}

impl<R> Section<R> for DebugAddr<R> {
    fn id() -> SectionId {
        SectionId::DebugAddr
    }

    fn reader(&self) -> &R {
        &self.section
    }
}

impl<R> From<R> for DebugAddr<R> {
    fn from(section: R) -> Self {
        DebugAddr { section }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::read::EndianSlice;
    use crate::test_util::GimliSectionMethods;
    use crate::{Format, LittleEndian};
    use test_assembler::{Endian, Label, LabelMaker, Section};

    #[test]
    fn test_get_address() {
        for format in vec![Format::Dwarf32, Format::Dwarf64] {
            for address_size in vec![4, 8] {
                let zero = Label::new();
                let length = Label::new();
                let start = Label::new();
                let first = Label::new();
                let end = Label::new();
                let mut section = Section::with_endian(Endian::Little)
                    .mark(&zero)
                    .initial_length(format, &length, &start)
                    .D16(5)
                    .D8(address_size)
                    .D8(0)
                    .mark(&first);
                for i in 0..20 {
                    section = section.word(address_size, 1000 + i);
                }
                section = section.mark(&end);
                length.set_const((&end - &start) as u64);

                let section = section.get_contents().unwrap();
                let debug_addr = DebugAddr::from(EndianSlice::new(&section, LittleEndian));
                let base = DebugAddrBase((&first - &zero) as usize);

                assert_eq!(
                    debug_addr.get_address(address_size, base, DebugAddrIndex(0)),
                    Ok(1000)
                );
                assert_eq!(
                    debug_addr.get_address(address_size, base, DebugAddrIndex(19)),
                    Ok(1019)
                );
            }
        }
    }
}