Merging upstream version 1.72.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1957 insertions, 0 deletions

diff --git a/vendor/gimli-0.27.3/src/write/line.rs b/vendor/gimli-0.27.3/src/write/line.rs
new file mode 100644
index 000000000..c88b735bc
--- /dev/null
+++ b/vendor/gimli-0.27.3/src/write/line.rs
@@ -0,0 +1,1957 @@
+use alloc::vec::Vec;
+use indexmap::{IndexMap, IndexSet};
+use std::ops::{Deref, DerefMut};
+
+use crate::common::{DebugLineOffset, Encoding, Format, LineEncoding, SectionId};
+use crate::constants;
+use crate::leb128;
+use crate::write::{
+    Address, DebugLineStrOffsets, DebugStrOffsets, Error, LineStringId, LineStringTable, Result,
+    Section, StringId, Writer,
+};
+
+/// The number assigned to the first special opcode.
+//
+// We output all instructions for all DWARF versions, since readers
+// should be able to ignore instructions they don't support.
+const OPCODE_BASE: u8 = 13;
+
+/// A line number program.
+#[derive(Debug, Clone)]
+pub struct LineProgram {
+    /// True if this line program was created with `LineProgram::none()`.
+    none: bool,
+    encoding: Encoding,
+    line_encoding: LineEncoding,
+
+    /// A list of source directory path names.
+    ///
+    /// If a path is relative, then the directory is located relative to the working
+    /// directory of the compilation unit.
+    ///
+    /// The first entry is for the working directory of the compilation unit.
+    directories: IndexSet<LineString>,
+
+    /// A list of source file entries.
+    ///
+    /// Each entry has a path name and a directory.
+    ///
+    /// If a path is a relative, then the file is located relative to the
+    /// directory. Otherwise the directory is meaningless.
+    ///
+    /// Does not include comp_file, even for version >= 5.
+    files: IndexMap<(LineString, DirectoryId), FileInfo>,
+
+    /// The primary source file of the compilation unit.
+    /// This is required for version >= 5, but we never reference it elsewhere
+    /// because DWARF defines DW_AT_decl_file=0 to mean not specified.
+    comp_file: (LineString, FileInfo),
+
+    /// True if the file entries may have valid timestamps.
+    ///
+    /// Entries may still have a timestamp of 0 even if this is set.
+    /// For version <= 4, this is ignored.
+    /// For version 5, this controls whether to emit `DW_LNCT_timestamp`.
+    pub file_has_timestamp: bool,
+
+    /// True if the file entries may have valid sizes.
+    ///
+    /// Entries may still have a size of 0 even if this is set.
+    /// For version <= 4, this is ignored.
+    /// For version 5, this controls whether to emit `DW_LNCT_size`.
+    pub file_has_size: bool,
+
+    /// True if the file entries have valid MD5 checksums.
+    ///
+    /// For version <= 4, this is ignored.
+    /// For version 5, this controls whether to emit `DW_LNCT_MD5`.
+    pub file_has_md5: bool,
+
+    prev_row: LineRow,
+    row: LineRow,
+    // TODO: this probably should be either rows or sequences instead
+    instructions: Vec<LineInstruction>,
+    in_sequence: bool,
+}
+
+impl LineProgram {
+    /// Create a new `LineProgram`.
+    ///
+    /// `comp_dir` defines the working directory of the compilation unit,
+    /// and must be the same as the `DW_AT_comp_dir` attribute
+    /// of the compilation unit DIE.
+    ///
+    /// `comp_file` and `comp_file_info` define the primary source file
+    /// of the compilation unit and must be the same as the `DW_AT_name`
+    /// attribute of the compilation unit DIE.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `line_encoding.line_base` > 0.
+    ///
+    /// Panics if `line_encoding.line_base` + `line_encoding.line_range` <= 0.
+    ///
+    /// Panics if `comp_dir` is empty or contains a null byte.
+    ///
+    /// Panics if `comp_file` is empty or contains a null byte.
+    pub fn new(
+        encoding: Encoding,
+        line_encoding: LineEncoding,
+        comp_dir: LineString,
+        comp_file: LineString,
+        comp_file_info: Option<FileInfo>,
+    ) -> LineProgram {
+        // We require a special opcode for a line advance of 0.
+        // See the debug_asserts in generate_row().
+        assert!(line_encoding.line_base <= 0);
+        assert!(line_encoding.line_base + line_encoding.line_range as i8 > 0);
+        let mut program = LineProgram {
+            none: false,
+            encoding,
+            line_encoding,
+            directories: IndexSet::new(),
+            files: IndexMap::new(),
+            comp_file: (comp_file, comp_file_info.unwrap_or_default()),
+            prev_row: LineRow::initial_state(line_encoding),
+            row: LineRow::initial_state(line_encoding),
+            instructions: Vec::new(),
+            in_sequence: false,
+            file_has_timestamp: false,
+            file_has_size: false,
+            file_has_md5: false,
+        };
+        // For all DWARF versions, directory index 0 is comp_dir.
+        // For version <= 4, the entry is implicit. We still add
+        // it here so that we use it, but we don't emit it.
+        program.add_directory(comp_dir);
+        program
+    }
+
+    /// Create a new `LineProgram` with no fields set.
+    ///
+    /// This can be used when the `LineProgram` will not be used.
+    ///
+    /// You should not attempt to add files or line instructions to
+    /// this line program, or write it to the `.debug_line` section.
+    pub fn none() -> Self {
+        let line_encoding = LineEncoding::default();
+        LineProgram {
+            none: true,
+            encoding: Encoding {
+                format: Format::Dwarf32,
+                version: 2,
+                address_size: 0,
+            },
+            line_encoding,
+            directories: IndexSet::new(),
+            files: IndexMap::new(),
+            comp_file: (LineString::String(Vec::new()), FileInfo::default()),
+            prev_row: LineRow::initial_state(line_encoding),
+            row: LineRow::initial_state(line_encoding),
+            instructions: Vec::new(),
+            in_sequence: false,
+            file_has_timestamp: false,
+            file_has_size: false,
+            file_has_md5: false,
+        }
+    }
+
+    /// Return true if this line program was created with `LineProgram::none()`.
+    #[inline]
+    pub fn is_none(&self) -> bool {
+        self.none
+    }
+
+    /// Return the encoding parameters for this line program.
+    #[inline]
+    pub fn encoding(&self) -> Encoding {
+        self.encoding
+    }
+
+    /// Return the DWARF version for this line program.
+    #[inline]
+    pub fn version(&self) -> u16 {
+        self.encoding.version
+    }
+
+    /// Return the address size in bytes for this line program.
+    #[inline]
+    pub fn address_size(&self) -> u8 {
+        self.encoding.address_size
+    }
+
+    /// Return the DWARF format for this line program.
+    #[inline]
+    pub fn format(&self) -> Format {
+        self.encoding.format
+    }
+
+    /// Return the id for the working directory of the compilation unit.
+    #[inline]
+    pub fn default_directory(&self) -> DirectoryId {
+        DirectoryId(0)
+    }
+
+    /// Add a directory entry and return its id.
+    ///
+    /// If the directory already exists, then return the id of the existing entry.
+    ///
+    /// If the path is relative, then the directory is located relative to the working
+    /// directory of the compilation unit.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `directory` is empty or contains a null byte.
+    pub fn add_directory(&mut self, directory: LineString) -> DirectoryId {
+        if let LineString::String(ref val) = directory {
+            // For DWARF version <= 4, directories must not be empty.
+            // The first directory isn't emitted so skip the check for it.
+            if self.encoding.version <= 4 && !self.directories.is_empty() {
+                assert!(!val.is_empty());
+            }
+            assert!(!val.contains(&0));
+        }
+        let (index, _) = self.directories.insert_full(directory);
+        DirectoryId(index)
+    }
+
+    /// Get a reference to a directory entry.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `id` is invalid.
+    pub fn get_directory(&self, id: DirectoryId) -> &LineString {
+        self.directories.get_index(id.0).unwrap()
+    }
+
+    /// Add a file entry and return its id.
+    ///
+    /// If the file already exists, then return the id of the existing entry.
+    ///
+    /// If the file path is relative, then the file is located relative
+    /// to the directory. Otherwise the directory is meaningless, but it
+    /// is still used as a key for file entries.
+    ///
+    /// If `info` is `None`, then new entries are assigned
+    /// default information, and existing entries are unmodified.
+    ///
+    /// If `info` is not `None`, then it is always assigned to the
+    /// entry, even if the entry already exists.
+    ///
+    /// # Panics
+    ///
+    /// Panics if 'file' is empty or contains a null byte.
+    pub fn add_file(
+        &mut self,
+        file: LineString,
+        directory: DirectoryId,
+        info: Option<FileInfo>,
+    ) -> FileId {
+        if let LineString::String(ref val) = file {
+            assert!(!val.is_empty());
+            assert!(!val.contains(&0));
+        }
+
+        let key = (file, directory);
+        let index = if let Some(info) = info {
+            let (index, _) = self.files.insert_full(key, info);
+            index
+        } else {
+            let entry = self.files.entry(key);
+            let index = entry.index();
+            entry.or_default();
+            index
+        };
+        FileId::new(index)
+    }
+
+    /// Get a reference to a file entry.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `id` is invalid.
+    pub fn get_file(&self, id: FileId) -> (&LineString, DirectoryId) {
+        match id.index() {
+            None => (&self.comp_file.0, DirectoryId(0)),
+            Some(index) => self
+                .files
+                .get_index(index)
+                .map(|entry| (&(entry.0).0, (entry.0).1))
+                .unwrap(),
+        }
+    }
+
+    /// Get a reference to the info for a file entry.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `id` is invalid.
+    pub fn get_file_info(&self, id: FileId) -> &FileInfo {
+        match id.index() {
+            None => &self.comp_file.1,
+            Some(index) => self.files.get_index(index).map(|entry| entry.1).unwrap(),
+        }
+    }
+
+    /// Get a mutable reference to the info for a file entry.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `id` is invalid.
+    pub fn get_file_info_mut(&mut self, id: FileId) -> &mut FileInfo {
+        match id.index() {
+            None => &mut self.comp_file.1,
+            Some(index) => self
+                .files
+                .get_index_mut(index)
+                .map(|entry| entry.1)
+                .unwrap(),
+        }
+    }
+
+    /// Begin a new sequence and set its base address.
+    ///
+    /// # Panics
+    ///
+    /// Panics if a sequence has already begun.
+    pub fn begin_sequence(&mut self, address: Option<Address>) {
+        assert!(!self.in_sequence);
+        self.in_sequence = true;
+        if let Some(address) = address {
+            self.instructions.push(LineInstruction::SetAddress(address));
+        }
+    }
+
+    /// End the sequence, and reset the row to its default values.
+    ///
+    /// Only the `address_offset` and op_index` fields of the current row are used.
+    ///
+    /// # Panics
+    ///
+    /// Panics if a sequence has not begun.
+    pub fn end_sequence(&mut self, address_offset: u64) {
+        assert!(self.in_sequence);
+        self.in_sequence = false;
+        self.row.address_offset = address_offset;
+        let op_advance = self.op_advance();
+        if op_advance != 0 {
+            self.instructions
+                .push(LineInstruction::AdvancePc(op_advance));
+        }
+        self.instructions.push(LineInstruction::EndSequence);
+        self.prev_row = LineRow::initial_state(self.line_encoding);
+        self.row = LineRow::initial_state(self.line_encoding);
+    }
+
+    /// Return true if a sequence has begun.
+    #[inline]
+    pub fn in_sequence(&self) -> bool {
+        self.in_sequence
+    }
+
+    /// Returns a reference to the data for the current row.
+    #[inline]
+    pub fn row(&mut self) -> &mut LineRow {
+        &mut self.row
+    }
+
+    /// Generates the line number information instructions for the current row.
+    ///
+    /// After the instructions are generated, it sets `discriminator` to 0, and sets
+    /// `basic_block`, `prologue_end`, and `epilogue_begin` to false.
+    ///
+    /// # Panics
+    ///
+    /// Panics if a sequence has not begun.
+    /// Panics if the address_offset decreases.
+    pub fn generate_row(&mut self) {
+        assert!(self.in_sequence);
+
+        // Output fields that are reset on every row.
+        if self.row.discriminator != 0 {
+            self.instructions
+                .push(LineInstruction::SetDiscriminator(self.row.discriminator));
+            self.row.discriminator = 0;
+        }
+        if self.row.basic_block {
+            self.instructions.push(LineInstruction::SetBasicBlock);
+            self.row.basic_block = false;
+        }
+        if self.row.prologue_end {
+            self.instructions.push(LineInstruction::SetPrologueEnd);
+            self.row.prologue_end = false;
+        }
+        if self.row.epilogue_begin {
+            self.instructions.push(LineInstruction::SetEpilogueBegin);
+            self.row.epilogue_begin = false;
+        }
+
+        // Output fields that are not reset on every row.
+        if self.row.is_statement != self.prev_row.is_statement {
+            self.instructions.push(LineInstruction::NegateStatement);
+        }
+        if self.row.file != self.prev_row.file {
+            self.instructions
+                .push(LineInstruction::SetFile(self.row.file));
+        }
+        if self.row.column != self.prev_row.column {
+            self.instructions
+                .push(LineInstruction::SetColumn(self.row.column));
+        }
+        if self.row.isa != self.prev_row.isa {
+            self.instructions
+                .push(LineInstruction::SetIsa(self.row.isa));
+        }
+
+        // Advance the line, address, and operation index.
+        let line_base = i64::from(self.line_encoding.line_base) as u64;
+        let line_range = u64::from(self.line_encoding.line_range);
+        let line_advance = self.row.line as i64 - self.prev_row.line as i64;
+        let op_advance = self.op_advance();
+
+        // Default to special advances of 0.
+        let special_base = u64::from(OPCODE_BASE);
+        // TODO: handle lack of special opcodes for 0 line advance
+        debug_assert!(self.line_encoding.line_base <= 0);
+        debug_assert!(self.line_encoding.line_base + self.line_encoding.line_range as i8 >= 0);
+        let special_default = special_base.wrapping_sub(line_base);
+        let mut special = special_default;
+        let mut use_special = false;
+
+        if line_advance != 0 {
+            let special_line = (line_advance as u64).wrapping_sub(line_base);
+            if special_line < line_range {
+                special = special_base + special_line;
+                use_special = true;
+            } else {
+                self.instructions
+                    .push(LineInstruction::AdvanceLine(line_advance));
+            }
+        }
+
+        if op_advance != 0 {
+            // Using ConstAddPc can save a byte.
+            let (special_op_advance, const_add_pc) = if special + op_advance * line_range <= 255 {
+                (op_advance, false)
+            } else {
+                let op_range = (255 - special_base) / line_range;
+                (op_advance - op_range, true)
+            };
+
+            let special_op = special_op_advance * line_range;
+            if special + special_op <= 255 {
+                special += special_op;
+                use_special = true;
+                if const_add_pc {
+                    self.instructions.push(LineInstruction::ConstAddPc);
+                }
+            } else {
+                self.instructions
+                    .push(LineInstruction::AdvancePc(op_advance));
+            }
+        }
+
+        if use_special && special != special_default {
+            debug_assert!(special >= special_base);
+            debug_assert!(special <= 255);
+            self.instructions
+                .push(LineInstruction::Special(special as u8));
+        } else {
+            self.instructions.push(LineInstruction::Copy);
+        }
+
+        self.prev_row = self.row;
+    }
+
+    fn op_advance(&self) -> u64 {
+        debug_assert!(self.row.address_offset >= self.prev_row.address_offset);
+        let mut address_advance = self.row.address_offset - self.prev_row.address_offset;
+        if self.line_encoding.minimum_instruction_length != 1 {
+            debug_assert_eq!(
+                self.row.address_offset % u64::from(self.line_encoding.minimum_instruction_length),
+                0
+            );
+            address_advance /= u64::from(self.line_encoding.minimum_instruction_length);
+        }
+        address_advance * u64::from(self.line_encoding.maximum_operations_per_instruction)
+            + self.row.op_index
+            - self.prev_row.op_index
+    }
+
+    /// Returns true if the line number program has no instructions.
+    ///
+    /// Does not check the file or directory entries.
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.instructions.is_empty()
+    }
+
+    /// Write the line number program to the given section.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `self.is_none()`.
+    pub fn write<W: Writer>(
+        &self,
+        w: &mut DebugLine<W>,
+        encoding: Encoding,
+        debug_line_str_offsets: &DebugLineStrOffsets,
+        debug_str_offsets: &DebugStrOffsets,
+    ) -> Result<DebugLineOffset> {
+        assert!(!self.is_none());
+
+        if encoding.version < self.version()
+            || encoding.format != self.format()
+            || encoding.address_size != self.address_size()
+        {
+            return Err(Error::IncompatibleLineProgramEncoding);
+        }
+
+        let offset = w.offset();
+
+        let length_offset = w.write_initial_length(self.format())?;
+        let length_base = w.len();
+
+        if self.version() < 2 || self.version() > 5 {
+            return Err(Error::UnsupportedVersion(self.version()));
+        }
+        w.write_u16(self.version())?;
+
+        if self.version() >= 5 {
+            w.write_u8(self.address_size())?;
+            // Segment selector size.
+            w.write_u8(0)?;
+        }
+
+        let header_length_offset = w.len();
+        w.write_udata(0, self.format().word_size())?;
+        let header_length_base = w.len();
+
+        w.write_u8(self.line_encoding.minimum_instruction_length)?;
+        if self.version() >= 4 {
+            w.write_u8(self.line_encoding.maximum_operations_per_instruction)?;
+        } else if self.line_encoding.maximum_operations_per_instruction != 1 {
+            return Err(Error::NeedVersion(4));
+        };
+        w.write_u8(if self.line_encoding.default_is_stmt {
+            1
+        } else {
+            0
+        })?;
+        w.write_u8(self.line_encoding.line_base as u8)?;
+        w.write_u8(self.line_encoding.line_range)?;
+        w.write_u8(OPCODE_BASE)?;
+        w.write(&[0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1])?;
+
+        if self.version() <= 4 {
+            // The first directory is stored as DW_AT_comp_dir.
+            for dir in self.directories.iter().skip(1) {
+                dir.write(
+                    w,
+                    constants::DW_FORM_string,
+                    self.encoding,
+                    debug_line_str_offsets,
+                    debug_str_offsets,
+                )?;
+            }
+            w.write_u8(0)?;
+
+            for ((file, dir), info) in self.files.iter() {
+                file.write(
+                    w,
+                    constants::DW_FORM_string,
+                    self.encoding,
+                    debug_line_str_offsets,
+                    debug_str_offsets,
+                )?;
+                w.write_uleb128(dir.0 as u64)?;
+                w.write_uleb128(info.timestamp)?;
+                w.write_uleb128(info.size)?;
+            }
+            w.write_u8(0)?;
+        } else {
+            // Directory entry formats (only ever 1).
+            w.write_u8(1)?;
+            w.write_uleb128(u64::from(constants::DW_LNCT_path.0))?;
+            let dir_form = self.directories.get_index(0).unwrap().form();
+            w.write_uleb128(dir_form.0.into())?;
+
+            // Directory entries.
+            w.write_uleb128(self.directories.len() as u64)?;
+            for dir in self.directories.iter() {
+                dir.write(
+                    w,
+                    dir_form,
+                    self.encoding,
+                    debug_line_str_offsets,
+                    debug_str_offsets,
+                )?;
+            }
+
+            // File name entry formats.
+            let count = 2
+                + if self.file_has_timestamp { 1 } else { 0 }
+                + if self.file_has_size { 1 } else { 0 }
+                + if self.file_has_md5 { 1 } else { 0 };
+            w.write_u8(count)?;
+            w.write_uleb128(u64::from(constants::DW_LNCT_path.0))?;
+            let file_form = self.comp_file.0.form();
+            w.write_uleb128(file_form.0.into())?;
+            w.write_uleb128(u64::from(constants::DW_LNCT_directory_index.0))?;
+            w.write_uleb128(constants::DW_FORM_udata.0.into())?;
+            if self.file_has_timestamp {
+                w.write_uleb128(u64::from(constants::DW_LNCT_timestamp.0))?;
+                w.write_uleb128(constants::DW_FORM_udata.0.into())?;
+            }
+            if self.file_has_size {
+                w.write_uleb128(u64::from(constants::DW_LNCT_size.0))?;
+                w.write_uleb128(constants::DW_FORM_udata.0.into())?;
+            }
+            if self.file_has_md5 {
+                w.write_uleb128(u64::from(constants::DW_LNCT_MD5.0))?;
+                w.write_uleb128(constants::DW_FORM_data16.0.into())?;
+            }
+
+            // File name entries.
+            w.write_uleb128(self.files.len() as u64 + 1)?;
+            let mut write_file = |file: &LineString, dir: DirectoryId, info: &FileInfo| {
+                file.write(
+                    w,
+                    file_form,
+                    self.encoding,
+                    debug_line_str_offsets,
+                    debug_str_offsets,
+                )?;
+                w.write_uleb128(dir.0 as u64)?;
+                if self.file_has_timestamp {
+                    w.write_uleb128(info.timestamp)?;
+                }
+                if self.file_has_size {
+                    w.write_uleb128(info.size)?;
+                }
+                if self.file_has_md5 {
+                    w.write(&info.md5)?;
+                }
+                Ok(())
+            };
+            write_file(&self.comp_file.0, DirectoryId(0), &self.comp_file.1)?;
+            for ((file, dir), info) in self.files.iter() {
+                write_file(file, *dir, info)?;
+            }
+        }
+
+        let header_length = (w.len() - header_length_base) as u64;
+        w.write_udata_at(
+            header_length_offset,
+            header_length,
+            self.format().word_size(),
+        )?;
+
+        for instruction in &self.instructions {
+            instruction.write(w, self.address_size())?;
+        }
+
+        let length = (w.len() - length_base) as u64;
+        w.write_initial_length_at(length_offset, length, self.format())?;
+
+        Ok(offset)
+    }
+}
+
+/// A row in the line number table that corresponds to a machine instruction.
+#[derive(Debug, Clone, Copy)]
+pub struct LineRow {
+    /// The offset of the instruction from the start address of the sequence.
+    pub address_offset: u64,
+    /// The index of an operation within a VLIW instruction.
+    ///
+    /// The index of the first operation is 0.
+    /// Set to 0 for non-VLIW instructions.
+    pub op_index: u64,
+
+    /// The source file corresponding to the instruction.
+    pub file: FileId,
+    /// The line number within the source file.
+    ///
+    /// Lines are numbered beginning at 1. Set to 0 if there is no source line.
+    pub line: u64,
+    /// The column number within the source line.
+    ///
+    /// Columns are numbered beginning at 1. Set to 0 for the "left edge" of the line.
+    pub column: u64,
+    /// An additional discriminator used to distinguish between source locations.
+    /// This value is assigned arbitrarily by the DWARF producer.
+    pub discriminator: u64,
+
+    /// Set to true if the instruction is a recommended breakpoint for a statement.
+    pub is_statement: bool,
+    /// Set to true if the instruction is the beginning of a basic block.
+    pub basic_block: bool,
+    /// Set to true if the instruction is a recommended breakpoint at the entry of a
+    /// function.
+    pub prologue_end: bool,
+    /// Set to true if the instruction is a recommended breakpoint prior to the exit of
+    /// a function.
+    pub epilogue_begin: bool,
+
+    /// The instruction set architecture of the instruction.
+    ///
+    /// Set to 0 for the default ISA. Other values are defined by the architecture ABI.
+    pub isa: u64,
+}
+
+impl LineRow {
+    /// Return the initial state as specified in the DWARF standard.
+    fn initial_state(line_encoding: LineEncoding) -> Self {
+        LineRow {
+            address_offset: 0,
+            op_index: 0,
+
+            file: FileId::initial_state(),
+            line: 1,
+            column: 0,
+            discriminator: 0,
+
+            is_statement: line_encoding.default_is_stmt,
+            basic_block: false,
+            prologue_end: false,
+            epilogue_begin: false,
+
+            isa: 0,
+        }
+    }
+}
+
+/// An instruction in a line number program.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum LineInstruction {
+    // Special opcodes
+    Special(u8),
+
+    // Standard opcodes
+    Copy,
+    AdvancePc(u64),
+    AdvanceLine(i64),
+    SetFile(FileId),
+    SetColumn(u64),
+    NegateStatement,
+    SetBasicBlock,
+    ConstAddPc,
+    // DW_LNS_fixed_advance_pc is not supported.
+    SetPrologueEnd,
+    SetEpilogueBegin,
+    SetIsa(u64),
+
+    // Extended opcodes
+    EndSequence,
+    // TODO: this doubles the size of this enum.
+    SetAddress(Address),
+    // DW_LNE_define_file is not supported.
+    SetDiscriminator(u64),
+}
+
+impl LineInstruction {
+    /// Write the line number instruction to the given section.
+    fn write<W: Writer>(self, w: &mut DebugLine<W>, address_size: u8) -> Result<()> {
+        use self::LineInstruction::*;
+        match self {
+            Special(val) => w.write_u8(val)?,
+            Copy => w.write_u8(constants::DW_LNS_copy.0)?,
+            AdvancePc(val) => {
+                w.write_u8(constants::DW_LNS_advance_pc.0)?;
+                w.write_uleb128(val)?;
+            }
+            AdvanceLine(val) => {
+                w.write_u8(constants::DW_LNS_advance_line.0)?;
+                w.write_sleb128(val)?;
+            }
+            SetFile(val) => {
+                w.write_u8(constants::DW_LNS_set_file.0)?;
+                w.write_uleb128(val.raw())?;
+            }
+            SetColumn(val) => {
+                w.write_u8(constants::DW_LNS_set_column.0)?;
+                w.write_uleb128(val)?;
+            }
+            NegateStatement => w.write_u8(constants::DW_LNS_negate_stmt.0)?,
+            SetBasicBlock => w.write_u8(constants::DW_LNS_set_basic_block.0)?,
+            ConstAddPc => w.write_u8(constants::DW_LNS_const_add_pc.0)?,
+            SetPrologueEnd => w.write_u8(constants::DW_LNS_set_prologue_end.0)?,
+            SetEpilogueBegin => w.write_u8(constants::DW_LNS_set_epilogue_begin.0)?,
+            SetIsa(val) => {
+                w.write_u8(constants::DW_LNS_set_isa.0)?;
+                w.write_uleb128(val)?;
+            }
+            EndSequence => {
+                w.write_u8(0)?;
+                w.write_uleb128(1)?;
+                w.write_u8(constants::DW_LNE_end_sequence.0)?;
+            }
+            SetAddress(address) => {
+                w.write_u8(0)?;
+                w.write_uleb128(1 + u64::from(address_size))?;
+                w.write_u8(constants::DW_LNE_set_address.0)?;
+                w.write_address(address, address_size)?;
+            }
+            SetDiscriminator(val) => {
+                let mut bytes = [0u8; 10];
+                // bytes is long enough so this will never fail.
+                let len = leb128::write::unsigned(&mut { &mut bytes[..] }, val).unwrap();
+                w.write_u8(0)?;
+                w.write_uleb128(1 + len as u64)?;
+                w.write_u8(constants::DW_LNE_set_discriminator.0)?;
+                w.write(&bytes[..len])?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// A string value for use in defining paths in line number programs.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum LineString {
+    /// A slice of bytes representing a string. Must not include null bytes.
+    /// Not guaranteed to be UTF-8 or anything like that.
+    String(Vec<u8>),
+
+    /// A reference to a string in the `.debug_str` section.
+    StringRef(StringId),
+
+    /// A reference to a string in the `.debug_line_str` section.
+    LineStringRef(LineStringId),
+}
+
+impl LineString {
+    /// Create a `LineString` using the normal form for the given encoding.
+    pub fn new<T>(val: T, encoding: Encoding, line_strings: &mut LineStringTable) -> Self
+    where
+        T: Into<Vec<u8>>,
+    {
+        let val = val.into();
+        if encoding.version <= 4 {
+            LineString::String(val)
+        } else {
+            LineString::LineStringRef(line_strings.add(val))
+        }
+    }
+
+    fn form(&self) -> constants::DwForm {
+        match *self {
+            LineString::String(..) => constants::DW_FORM_string,
+            LineString::StringRef(..) => constants::DW_FORM_strp,
+            LineString::LineStringRef(..) => constants::DW_FORM_line_strp,
+        }
+    }
+
+    fn write<W: Writer>(
+        &self,
+        w: &mut DebugLine<W>,
+        form: constants::DwForm,
+        encoding: Encoding,
+        debug_line_str_offsets: &DebugLineStrOffsets,
+        debug_str_offsets: &DebugStrOffsets,
+    ) -> Result<()> {
+        if form != self.form() {
+            return Err(Error::LineStringFormMismatch);
+        }
+
+        match *self {
+            LineString::String(ref val) => {
+                if encoding.version <= 4 {
+                    debug_assert!(!val.is_empty());
+                }
+                w.write(val)?;
+                w.write_u8(0)?;
+            }
+            LineString::StringRef(val) => {
+                if encoding.version < 5 {
+                    return Err(Error::NeedVersion(5));
+                }
+                w.write_offset(
+                    debug_str_offsets.get(val).0,
+                    SectionId::DebugStr,
+                    encoding.format.word_size(),
+                )?;
+            }
+            LineString::LineStringRef(val) => {
+                if encoding.version < 5 {
+                    return Err(Error::NeedVersion(5));
+                }
+                w.write_offset(
+                    debug_line_str_offsets.get(val).0,
+                    SectionId::DebugLineStr,
+                    encoding.format.word_size(),
+                )?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// An identifier for a directory in a `LineProgram`.
+///
+/// Defaults to the working directory of the compilation unit.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct DirectoryId(usize);
+
+// Force FileId access via the methods.
+mod id {
+    /// An identifier for a file in a `LineProgram`.
+    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+    pub struct FileId(usize);
+
+    impl FileId {
+        /// Create a FileId given an index into `LineProgram::files`.
+        pub(crate) fn new(index: usize) -> Self {
+            FileId(index + 1)
+        }
+
+        /// The index of the file in `LineProgram::files`.
+        pub(super) fn index(self) -> Option<usize> {
+            if self.0 == 0 {
+                None
+            } else {
+                Some(self.0 - 1)
+            }
+        }
+
+        /// The initial state of the file register.
+        pub(super) fn initial_state() -> Self {
+            FileId(1)
+        }
+
+        /// The raw value used when writing.
+        pub(crate) fn raw(self) -> u64 {
+            self.0 as u64
+        }
+
+        /// The id for file index 0 in DWARF version 5.
+        /// Only used when converting.
+        // Used for tests only.
+        #[allow(unused)]
+        pub(super) fn zero() -> Self {
+            FileId(0)
+        }
+    }
+}
+pub use self::id::*;
+
+/// Extra information for file in a `LineProgram`.
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
+pub struct FileInfo {
+    /// The implementation defined timestamp of the last modification of the file,
+    /// or 0 if not available.
+    pub timestamp: u64,
+
+    /// The size of the file in bytes, or 0 if not available.
+    pub size: u64,
+
+    /// A 16-byte MD5 digest of the file contents.
+    ///
+    /// Only used if version >= 5 and `LineProgram::file_has_md5` is `true`.
+    pub md5: [u8; 16],
+}
+
+define_section!(
+    DebugLine,
+    DebugLineOffset,
+    "A writable `.debug_line` section."
+);
+
+#[cfg(feature = "read")]
+mod convert {
+    use super::*;
+    use crate::read::{self, Reader};
+    use crate::write::{self, ConvertError, ConvertResult};
+
+    impl LineProgram {
+        /// Create a line number program by reading the data from the given program.
+        ///
+        /// Return the program and a mapping from file index to `FileId`.
+        pub fn from<R: Reader<Offset = usize>>(
+            mut from_program: read::IncompleteLineProgram<R>,
+            dwarf: &read::Dwarf<R>,
+            line_strings: &mut write::LineStringTable,
+            strings: &mut write::StringTable,
+            convert_address: &dyn Fn(u64) -> Option<Address>,
+        ) -> ConvertResult<(LineProgram, Vec<FileId>)> {
+            // Create mappings in case the source has duplicate files or directories.
+            let mut dirs = Vec::new();
+            let mut files = Vec::new();
+
+            let mut program = {
+                let from_header = from_program.header();
+                let encoding = from_header.encoding();
+
+                let comp_dir = match from_header.directory(0) {
+                    Some(comp_dir) => LineString::from(comp_dir, dwarf, line_strings, strings)?,
+                    None => LineString::new(&[][..], encoding, line_strings),
+                };
+
+                let (comp_name, comp_file_info) = match from_header.file(0) {
+                    Some(comp_file) => {
+                        if comp_file.directory_index() != 0 {
+                            return Err(ConvertError::InvalidDirectoryIndex);
+                        }
+                        (
+                            LineString::from(comp_file.path_name(), dwarf, line_strings, strings)?,
+                            Some(FileInfo {
+                                timestamp: comp_file.timestamp(),
+                                size: comp_file.size(),
+                                md5: *comp_file.md5(),
+                            }),
+                        )
+                    }
+                    None => (LineString::new(&[][..], encoding, line_strings), None),
+                };
+
+                if from_header.line_base() > 0 {
+                    return Err(ConvertError::InvalidLineBase);
+                }
+                let mut program = LineProgram::new(
+                    encoding,
+                    from_header.line_encoding(),
+                    comp_dir,
+                    comp_name,
+                    comp_file_info,
+                );
+
+                let file_skip;
+                if from_header.version() <= 4 {
+                    // The first directory is implicit.
+                    dirs.push(DirectoryId(0));
+                    // A file index of 0 is invalid for version <= 4, but putting
+                    // something there makes the indexing easier.
+                    file_skip = 0;
+                    files.push(FileId::zero());
+                } else {
+                    // We don't add the first file to `files`, but still allow
+                    // it to be referenced from converted instructions.
+                    file_skip = 1;
+                    files.push(FileId::zero());
+                }
+
+                for from_dir in from_header.include_directories() {
+                    let from_dir =
+                        LineString::from(from_dir.clone(), dwarf, line_strings, strings)?;
+                    dirs.push(program.add_directory(from_dir));
+                }
+
+                program.file_has_timestamp = from_header.file_has_timestamp();
+                program.file_has_size = from_header.file_has_size();
+                program.file_has_md5 = from_header.file_has_md5();
+                for from_file in from_header.file_names().iter().skip(file_skip) {
+                    let from_name =
+                        LineString::from(from_file.path_name(), dwarf, line_strings, strings)?;
+                    let from_dir = from_file.directory_index();
+                    if from_dir >= dirs.len() as u64 {
+                        return Err(ConvertError::InvalidDirectoryIndex);
+                    }
+                    let from_dir = dirs[from_dir as usize];
+                    let from_info = Some(FileInfo {
+                        timestamp: from_file.timestamp(),
+                        size: from_file.size(),
+                        md5: *from_file.md5(),
+                    });
+                    files.push(program.add_file(from_name, from_dir, from_info));
+                }
+
+                program
+            };
+
+            // We can't use the `from_program.rows()` because that wouldn't let
+            // us preserve address relocations.
+            let mut from_row = read::LineRow::new(from_program.header());
+            let mut instructions = from_program.header().instructions();
+            let mut address = None;
+            while let Some(instruction) = instructions.next_instruction(from_program.header())? {
+                match instruction {
+                    read::LineInstruction::SetAddress(val) => {
+                        if program.in_sequence() {
+                            return Err(ConvertError::UnsupportedLineInstruction);
+                        }
+                        match convert_address(val) {
+                            Some(val) => address = Some(val),
+                            None => return Err(ConvertError::InvalidAddress),
+                        }
+                        from_row.execute(read::LineInstruction::SetAddress(0), &mut from_program);
+                    }
+                    read::LineInstruction::DefineFile(_) => {
+                        return Err(ConvertError::UnsupportedLineInstruction);
+                    }
+                    _ => {
+                        if from_row.execute(instruction, &mut from_program) {
+                            if !program.in_sequence() {
+                                program.begin_sequence(address);
+                                address = None;
+                            }
+                            if from_row.end_sequence() {
+                                program.end_sequence(from_row.address());
+                            } else {
+                                program.row().address_offset = from_row.address();
+                                program.row().op_index = from_row.op_index();
+                                program.row().file = {
+                                    let file = from_row.file_index();
+                                    if file >= files.len() as u64 {
+                                        return Err(ConvertError::InvalidFileIndex);
+                                    }
+                                    if file == 0 && program.version() <= 4 {
+                                        return Err(ConvertError::InvalidFileIndex);
+                                    }
+                                    files[file as usize]
+                                };
+                                program.row().line = match from_row.line() {
+                                    Some(line) => line.get(),
+                                    None => 0,
+                                };
+                                program.row().column = match from_row.column() {
+                                    read::ColumnType::LeftEdge => 0,
+                                    read::ColumnType::Column(val) => val.get(),
+                                };
+                                program.row().discriminator = from_row.discriminator();
+                                program.row().is_statement = from_row.is_stmt();
+                                program.row().basic_block = from_row.basic_block();
+                                program.row().prologue_end = from_row.prologue_end();
+                                program.row().epilogue_begin = from_row.epilogue_begin();
+                                program.row().isa = from_row.isa();
+                                program.generate_row();
+                            }
+                            from_row.reset(from_program.header());
+                        }
+                    }
+                };
+            }
+            Ok((program, files))
+        }
+    }
+
+    impl LineString {
+        fn from<R: Reader<Offset = usize>>(
+            from_attr: read::AttributeValue<R>,
+            dwarf: &read::Dwarf<R>,
+            line_strings: &mut write::LineStringTable,
+            strings: &mut write::StringTable,
+        ) -> ConvertResult<LineString> {
+            Ok(match from_attr {
+                read::AttributeValue::String(r) => LineString::String(r.to_slice()?.to_vec()),
+                read::AttributeValue::DebugStrRef(offset) => {
+                    let r = dwarf.debug_str.get_str(offset)?;
+                    let id = strings.add(r.to_slice()?);
+                    LineString::StringRef(id)
+                }
+                read::AttributeValue::DebugLineStrRef(offset) => {
+                    let r = dwarf.debug_line_str.get_str(offset)?;
+                    let id = line_strings.add(r.to_slice()?);
+                    LineString::LineStringRef(id)
+                }
+                _ => return Err(ConvertError::UnsupportedLineStringForm),
+            })
+        }
+    }
+}
+
+#[cfg(test)]
+#[cfg(feature = "read")]
+mod tests {
+    use super::*;
+    use crate::read;
+    use crate::write::{DebugLineStr, DebugStr, EndianVec, StringTable};
+    use crate::LittleEndian;
+
+    #[test]
+    fn test_line_program_table() {
+        let dir1 = LineString::String(b"dir1".to_vec());
+        let file1 = LineString::String(b"file1".to_vec());
+        let dir2 = LineString::String(b"dir2".to_vec());
+        let file2 = LineString::String(b"file2".to_vec());
+
+        let mut programs = Vec::new();
+        for &version in &[2, 3, 4, 5] {
+            for &address_size in &[4, 8] {
+                for &format in &[Format::Dwarf32, Format::Dwarf64] {
+                    let encoding = Encoding {
+                        format,
+                        version,
+                        address_size,
+                    };
+                    let mut program = LineProgram::new(
+                        encoding,
+                        LineEncoding::default(),
+                        dir1.clone(),
+                        file1.clone(),
+                        None,
+                    );
+
+                    {
+                        assert_eq!(&dir1, program.get_directory(program.default_directory()));
+                        program.file_has_timestamp = true;
+                        program.file_has_size = true;
+                        if encoding.version >= 5 {
+                            program.file_has_md5 = true;
+                        }
+
+                        let dir_id = program.add_directory(dir2.clone());
+                        assert_eq!(&dir2, program.get_directory(dir_id));
+                        assert_eq!(dir_id, program.add_directory(dir2.clone()));
+
+                        let file_info = FileInfo {
+                            timestamp: 1,
+                            size: 2,
+                            md5: if encoding.version >= 5 {
+                                [3; 16]
+                            } else {
+                                [0; 16]
+                            },
+                        };
+                        let file_id = program.add_file(file2.clone(), dir_id, Some(file_info));
+                        assert_eq!((&file2, dir_id), program.get_file(file_id));
+                        assert_eq!(file_info, *program.get_file_info(file_id));
+
+                        program.get_file_info_mut(file_id).size = 3;
+                        assert_ne!(file_info, *program.get_file_info(file_id));
+                        assert_eq!(file_id, program.add_file(file2.clone(), dir_id, None));
+                        assert_ne!(file_info, *program.get_file_info(file_id));
+                        assert_eq!(
+                            file_id,
+                            program.add_file(file2.clone(), dir_id, Some(file_info))
+                        );
+                        assert_eq!(file_info, *program.get_file_info(file_id));
+
+                        programs.push((program, file_id, encoding));
+                    }
+                }
+            }
+        }
+
+        let debug_line_str_offsets = DebugLineStrOffsets::none();
+        let debug_str_offsets = DebugStrOffsets::none();
+        let mut debug_line = DebugLine::from(EndianVec::new(LittleEndian));
+        let mut debug_line_offsets = Vec::new();
+        for (program, _, encoding) in &programs {
+            debug_line_offsets.push(
+                program
+                    .write(
+                        &mut debug_line,
+                        *encoding,
+                        &debug_line_str_offsets,
+                        &debug_str_offsets,
+                    )
+                    .unwrap(),
+            );
+        }
+
+        let read_debug_line = read::DebugLine::new(debug_line.slice(), LittleEndian);
+
+        let convert_address = &|address| Some(Address::Constant(address));
+        for ((program, file_id, encoding), offset) in programs.iter().zip(debug_line_offsets.iter())
+        {
+            let read_program = read_debug_line
+                .program(
+                    *offset,
+                    encoding.address_size,
+                    Some(read::EndianSlice::new(b"dir1", LittleEndian)),
+                    Some(read::EndianSlice::new(b"file1", LittleEndian)),
+                )
+                .unwrap();
+
+            let dwarf = read::Dwarf::default();
+            let mut convert_line_strings = LineStringTable::default();
+            let mut convert_strings = StringTable::default();
+            let (convert_program, convert_files) = LineProgram::from(
+                read_program,
+                &dwarf,
+                &mut convert_line_strings,
+                &mut convert_strings,
+                convert_address,
+            )
+            .unwrap();
+            assert_eq!(convert_program.version(), program.version());
+            assert_eq!(convert_program.address_size(), program.address_size());
+            assert_eq!(convert_program.format(), program.format());
+
+            let convert_file_id = convert_files[file_id.raw() as usize];
+            let (file, dir) = program.get_file(*file_id);
+            let (convert_file, convert_dir) = convert_program.get_file(convert_file_id);
+            assert_eq!(file, convert_file);
+            assert_eq!(
+                program.get_directory(dir),
+                convert_program.get_directory(convert_dir)
+            );
+            assert_eq!(
+                program.get_file_info(*file_id),
+                convert_program.get_file_info(convert_file_id)
+            );
+        }
+    }
+
+    #[test]
+    fn test_line_row() {
+        let dir1 = &b"dir1"[..];
+        let file1 = &b"file1"[..];
+        let file2 = &b"file2"[..];
+        let convert_address = &|address| Some(Address::Constant(address));
+
+        let debug_line_str_offsets = DebugLineStrOffsets::none();
+        let debug_str_offsets = DebugStrOffsets::none();
+
+        for &version in &[2, 3, 4, 5] {
+            for &address_size in &[4, 8] {
+                for &format in &[Format::Dwarf32, Format::Dwarf64] {
+                    let encoding = Encoding {
+                        format,
+                        version,
+                        address_size,
+                    };
+                    let line_base = -5;
+                    let line_range = 14;
+                    let neg_line_base = (-line_base) as u8;
+                    let mut program = LineProgram::new(
+                        encoding,
+                        LineEncoding {
+                            line_base,
+                            line_range,
+                            ..Default::default()
+                        },
+                        LineString::String(dir1.to_vec()),
+                        LineString::String(file1.to_vec()),
+                        None,
+                    );
+                    let dir_id = program.default_directory();
+                    program.add_file(LineString::String(file1.to_vec()), dir_id, None);
+                    let file_id =
+                        program.add_file(LineString::String(file2.to_vec()), dir_id, None);
+
+                    // Test sequences.
+                    {
+                        let mut program = program.clone();
+                        let address = Address::Constant(0x12);
+                        program.begin_sequence(Some(address));
+                        assert_eq!(
+                            program.instructions,
+                            vec![LineInstruction::SetAddress(address)]
+                        );
+                    }
+
+                    {
+                        let mut program = program.clone();
+                        program.begin_sequence(None);
+                        assert_eq!(program.instructions, Vec::new());
+                    }
+
+                    {
+                        let mut program = program.clone();
+                        program.begin_sequence(None);
+                        program.end_sequence(0x1234);
+                        assert_eq!(
+                            program.instructions,
+                            vec![
+                                LineInstruction::AdvancePc(0x1234),
+                                LineInstruction::EndSequence
+                            ]
+                        );
+                    }
+
+                    // Create a base program.
+                    program.begin_sequence(None);
+                    program.row.line = 0x1000;
+                    program.generate_row();
+                    let base_row = program.row;
+                    let base_instructions = program.instructions.clone();
+
+                    // Create test cases.
+                    let mut tests = Vec::new();
+
+                    let row = base_row;
+                    tests.push((row, vec![LineInstruction::Copy]));
+
+                    let mut row = base_row;
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((row, vec![LineInstruction::Special(OPCODE_BASE)]));
+
+                    let mut row = base_row;
+                    row.line += u64::from(line_range) - 1;
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![LineInstruction::Special(OPCODE_BASE + line_range - 1)],
+                    ));
+
+                    let mut row = base_row;
+                    row.line += u64::from(line_range);
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![
+                            LineInstruction::AdvanceLine(i64::from(line_range - neg_line_base)),
+                            LineInstruction::Copy,
+                        ],
+                    ));
+
+                    let mut row = base_row;
+                    row.address_offset = 1;
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![LineInstruction::Special(OPCODE_BASE + line_range)],
+                    ));
+
+                    let op_range = (255 - OPCODE_BASE) / line_range;
+                    let mut row = base_row;
+                    row.address_offset = u64::from(op_range);
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![LineInstruction::Special(
+                            OPCODE_BASE + op_range * line_range,
+                        )],
+                    ));
+
+                    let mut row = base_row;
+                    row.address_offset = u64::from(op_range);
+                    row.line += u64::from(255 - OPCODE_BASE - op_range * line_range);
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((row, vec![LineInstruction::Special(255)]));
+
+                    let mut row = base_row;
+                    row.address_offset = u64::from(op_range);
+                    row.line += u64::from(255 - OPCODE_BASE - op_range * line_range) + 1;
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![LineInstruction::ConstAddPc, LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.address_offset = u64::from(op_range);
+                    row.line += u64::from(255 - OPCODE_BASE - op_range * line_range) + 2;
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![
+                            LineInstruction::ConstAddPc,
+                            LineInstruction::Special(OPCODE_BASE + 6),
+                        ],
+                    ));
+
+                    let mut row = base_row;
+                    row.address_offset = u64::from(op_range) * 2;
+                    row.line += u64::from(255 - OPCODE_BASE - op_range * line_range);
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![LineInstruction::ConstAddPc, LineInstruction::Special(255)],
+                    ));
+
+                    let mut row = base_row;
+                    row.address_offset = u64::from(op_range) * 2;
+                    row.line += u64::from(255 - OPCODE_BASE - op_range * line_range) + 1;
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![
+                            LineInstruction::AdvancePc(row.address_offset),
+                            LineInstruction::Copy,
+                        ],
+                    ));
+
+                    let mut row = base_row;
+                    row.address_offset = u64::from(op_range) * 2;
+                    row.line += u64::from(255 - OPCODE_BASE - op_range * line_range) + 2;
+                    row.line -= u64::from(neg_line_base);
+                    tests.push((
+                        row,
+                        vec![
+                            LineInstruction::AdvancePc(row.address_offset),
+                            LineInstruction::Special(OPCODE_BASE + 6),
+                        ],
+                    ));
+
+                    let mut row = base_row;
+                    row.address_offset = 0x1234;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::AdvancePc(0x1234), LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.line += 0x1234;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::AdvanceLine(0x1234), LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.file = file_id;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::SetFile(file_id), LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.column = 0x1234;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::SetColumn(0x1234), LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.discriminator = 0x1234;
+                    tests.push((
+                        row,
+                        vec![
+                            LineInstruction::SetDiscriminator(0x1234),
+                            LineInstruction::Copy,
+                        ],
+                    ));
+
+                    let mut row = base_row;
+                    row.is_statement = !row.is_statement;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::NegateStatement, LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.basic_block = true;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::SetBasicBlock, LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.prologue_end = true;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::SetPrologueEnd, LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.epilogue_begin = true;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::SetEpilogueBegin, LineInstruction::Copy],
+                    ));
+
+                    let mut row = base_row;
+                    row.isa = 0x1234;
+                    tests.push((
+                        row,
+                        vec![LineInstruction::SetIsa(0x1234), LineInstruction::Copy],
+                    ));
+
+                    for test in tests {
+                        // Test generate_row().
+                        let mut program = program.clone();
+                        program.row = test.0;
+                        program.generate_row();
+                        assert_eq!(
+                            &program.instructions[base_instructions.len()..],
+                            &test.1[..]
+                        );
+
+                        // Test LineProgram::from().
+                        let mut debug_line = DebugLine::from(EndianVec::new(LittleEndian));
+                        let debug_line_offset = program
+                            .write(
+                                &mut debug_line,
+                                encoding,
+                                &debug_line_str_offsets,
+                                &debug_str_offsets,
+                            )
+                            .unwrap();
+
+                        let read_debug_line =
+                            read::DebugLine::new(debug_line.slice(), LittleEndian);
+                        let read_program = read_debug_line
+                            .program(
+                                debug_line_offset,
+                                address_size,
+                                Some(read::EndianSlice::new(dir1, LittleEndian)),
+                                Some(read::EndianSlice::new(file1, LittleEndian)),
+                            )
+                            .unwrap();
+
+                        let dwarf = read::Dwarf::default();
+                        let mut convert_line_strings = LineStringTable::default();
+                        let mut convert_strings = StringTable::default();
+                        let (convert_program, _convert_files) = LineProgram::from(
+                            read_program,
+                            &dwarf,
+                            &mut convert_line_strings,
+                            &mut convert_strings,
+                            convert_address,
+                        )
+                        .unwrap();
+                        assert_eq!(
+                            &convert_program.instructions[base_instructions.len()..],
+                            &test.1[..]
+                        );
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn test_line_instruction() {
+        let dir1 = &b"dir1"[..];
+        let file1 = &b"file1"[..];
+
+        let debug_line_str_offsets = DebugLineStrOffsets::none();
+        let debug_str_offsets = DebugStrOffsets::none();
+
+        for &version in &[2, 3, 4, 5] {
+            for &address_size in &[4, 8] {
+                for &format in &[Format::Dwarf32, Format::Dwarf64] {
+                    let encoding = Encoding {
+                        format,
+                        version,
+                        address_size,
+                    };
+                    let mut program = LineProgram::new(
+                        encoding,
+                        LineEncoding::default(),
+                        LineString::String(dir1.to_vec()),
+                        LineString::String(file1.to_vec()),
+                        None,
+                    );
+                    let dir_id = program.default_directory();
+                    let file_id =
+                        program.add_file(LineString::String(file1.to_vec()), dir_id, None);
+
+                    for &(ref inst, ref expect_inst) in &[
+                        (
+                            LineInstruction::Special(OPCODE_BASE),
+                            read::LineInstruction::Special(OPCODE_BASE),
+                        ),
+                        (
+                            LineInstruction::Special(255),
+                            read::LineInstruction::Special(255),
+                        ),
+                        (LineInstruction::Copy, read::LineInstruction::Copy),
+                        (
+                            LineInstruction::AdvancePc(0x12),
+                            read::LineInstruction::AdvancePc(0x12),
+                        ),
+                        (
+                            LineInstruction::AdvanceLine(0x12),
+                            read::LineInstruction::AdvanceLine(0x12),
+                        ),
+                        (
+                            LineInstruction::SetFile(file_id),
+                            read::LineInstruction::SetFile(file_id.raw()),
+                        ),
+                        (
+                            LineInstruction::SetColumn(0x12),
+                            read::LineInstruction::SetColumn(0x12),
+                        ),
+                        (
+                            LineInstruction::NegateStatement,
+                            read::LineInstruction::NegateStatement,
+                        ),
+                        (
+                            LineInstruction::SetBasicBlock,
+                            read::LineInstruction::SetBasicBlock,
+                        ),
+                        (
+                            LineInstruction::ConstAddPc,
+                            read::LineInstruction::ConstAddPc,
+                        ),
+                        (
+                            LineInstruction::SetPrologueEnd,
+                            read::LineInstruction::SetPrologueEnd,
+                        ),
+                        (
+                            LineInstruction::SetEpilogueBegin,
+                            read::LineInstruction::SetEpilogueBegin,
+                        ),
+                        (
+                            LineInstruction::SetIsa(0x12),
+                            read::LineInstruction::SetIsa(0x12),
+                        ),
+                        (
+                            LineInstruction::EndSequence,
+                            read::LineInstruction::EndSequence,
+                        ),
+                        (
+                            LineInstruction::SetAddress(Address::Constant(0x12)),
+                            read::LineInstruction::SetAddress(0x12),
+                        ),
+                        (
+                            LineInstruction::SetDiscriminator(0x12),
+                            read::LineInstruction::SetDiscriminator(0x12),
+                        ),
+                    ][..]
+                    {
+                        let mut program = program.clone();
+                        program.instructions.push(*inst);
+
+                        let mut debug_line = DebugLine::from(EndianVec::new(LittleEndian));
+                        let debug_line_offset = program
+                            .write(
+                                &mut debug_line,
+                                encoding,
+                                &debug_line_str_offsets,
+                                &debug_str_offsets,
+                            )
+                            .unwrap();
+
+                        let read_debug_line =
+                            read::DebugLine::new(debug_line.slice(), LittleEndian);
+                        let read_program = read_debug_line
+                            .program(
+                                debug_line_offset,
+                                address_size,
+                                Some(read::EndianSlice::new(dir1, LittleEndian)),
+                                Some(read::EndianSlice::new(file1, LittleEndian)),
+                            )
+                            .unwrap();
+                        let read_header = read_program.header();
+                        let mut read_insts = read_header.instructions();
+                        assert_eq!(
+                            *expect_inst,
+                            read_insts.next_instruction(read_header).unwrap().unwrap()
+                        );
+                        assert_eq!(None, read_insts.next_instruction(read_header).unwrap());
+                    }
+                }
+            }
+        }
+    }
+
+    // Test that the address/line advance is correct. We don't test for optimality.
+    #[test]
+    fn test_advance() {
+        let encoding = Encoding {
+            format: Format::Dwarf32,
+            version: 4,
+            address_size: 8,
+        };
+
+        let dir1 = &b"dir1"[..];
+        let file1 = &b"file1"[..];
+
+        let addresses = 0..50;
+        let lines = -10..25i64;
+
+        let debug_line_str_offsets = DebugLineStrOffsets::none();
+        let debug_str_offsets = DebugStrOffsets::none();
+
+        for minimum_instruction_length in vec![1, 4] {
+            for maximum_operations_per_instruction in vec![1, 3] {
+                for line_base in vec![-5, 0] {
+                    for line_range in vec![10, 20] {
+                        let line_encoding = LineEncoding {
+                            minimum_instruction_length,
+                            maximum_operations_per_instruction,
+                            line_base,
+                            line_range,
+                            default_is_stmt: true,
+                        };
+                        let mut program = LineProgram::new(
+                            encoding,
+                            line_encoding,
+                            LineString::String(dir1.to_vec()),
+                            LineString::String(file1.to_vec()),
+                            None,
+                        );
+                        for address_advance in addresses.clone() {
+                            program.begin_sequence(Some(Address::Constant(0x1000)));
+                            program.row().line = 0x10000;
+                            program.generate_row();
+                            for line_advance in lines.clone() {
+                                {
+                                    let row = program.row();
+                                    row.address_offset +=
+                                        address_advance * u64::from(minimum_instruction_length);
+                                    row.line = row.line.wrapping_add(line_advance as u64);
+                                }
+                                program.generate_row();
+                            }
+                            let address_offset = program.row().address_offset
+                                + u64::from(minimum_instruction_length);
+                            program.end_sequence(address_offset);
+                        }
+
+                        let mut debug_line = DebugLine::from(EndianVec::new(LittleEndian));
+                        let debug_line_offset = program
+                            .write(
+                                &mut debug_line,
+                                encoding,
+                                &debug_line_str_offsets,
+                                &debug_str_offsets,
+                            )
+                            .unwrap();
+
+                        let read_debug_line =
+                            read::DebugLine::new(debug_line.slice(), LittleEndian);
+                        let read_program = read_debug_line
+                            .program(
+                                debug_line_offset,
+                                8,
+                                Some(read::EndianSlice::new(dir1, LittleEndian)),
+                                Some(read::EndianSlice::new(file1, LittleEndian)),
+                            )
+                            .unwrap();
+
+                        let mut rows = read_program.rows();
+                        for address_advance in addresses.clone() {
+                            let mut address;
+                            let mut line;
+                            {
+                                let row = rows.next_row().unwrap().unwrap().1;
+                                address = row.address();
+                                line = row.line().unwrap().get();
+                            }
+                            assert_eq!(address, 0x1000);
+                            assert_eq!(line, 0x10000);
+                            for line_advance in lines.clone() {
+                                let row = rows.next_row().unwrap().unwrap().1;
+                                assert_eq!(
+                                    row.address() - address,
+                                    address_advance * u64::from(minimum_instruction_length)
+                                );
+                                assert_eq!(
+                                    (row.line().unwrap().get() as i64) - (line as i64),
+                                    line_advance
+                                );
+                                address = row.address();
+                                line = row.line().unwrap().get();
+                            }
+                            let row = rows.next_row().unwrap().unwrap().1;
+                            assert!(row.end_sequence());
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn test_line_string() {
+        let version = 5;
+
+        let file = b"file1";
+
+        let mut strings = StringTable::default();
+        let string_id = strings.add("file2");
+        let mut debug_str = DebugStr::from(EndianVec::new(LittleEndian));
+        let debug_str_offsets = strings.write(&mut debug_str).unwrap();
+
+        let mut line_strings = LineStringTable::default();
+        let line_string_id = line_strings.add("file3");
+        let mut debug_line_str = DebugLineStr::from(EndianVec::new(LittleEndian));
+        let debug_line_str_offsets = line_strings.write(&mut debug_line_str).unwrap();
+
+        for &address_size in &[4, 8] {
+            for &format in &[Format::Dwarf32, Format::Dwarf64] {
+                let encoding = Encoding {
+                    format,
+                    version,
+                    address_size,
+                };
+
+                for (file, expect_file) in vec![
+                    (
+                        LineString::String(file.to_vec()),
+                        read::AttributeValue::String(read::EndianSlice::new(file, LittleEndian)),
+                    ),
+                    (
+                        LineString::StringRef(string_id),
+                        read::AttributeValue::DebugStrRef(debug_str_offsets.get(string_id)),
+                    ),
+                    (
+                        LineString::LineStringRef(line_string_id),
+                        read::AttributeValue::DebugLineStrRef(
+                            debug_line_str_offsets.get(line_string_id),
+                        ),
+                    ),
+                ] {
+                    let program = LineProgram::new(
+                        encoding,
+                        LineEncoding::default(),
+                        LineString::String(b"dir".to_vec()),
+                        file,
+                        None,
+                    );
+
+                    let mut debug_line = DebugLine::from(EndianVec::new(LittleEndian));
+                    let debug_line_offset = program
+                        .write(
+                            &mut debug_line,
+                            encoding,
+                            &debug_line_str_offsets,
+                            &debug_str_offsets,
+                        )
+                        .unwrap();
+
+                    let read_debug_line = read::DebugLine::new(debug_line.slice(), LittleEndian);
+                    let read_program = read_debug_line
+                        .program(debug_line_offset, address_size, None, None)
+                        .unwrap();
+                    let read_header = read_program.header();
+                    assert_eq!(read_header.file(0).unwrap().path_name(), expect_file);
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn test_missing_comp_dir() {
+        let debug_line_str_offsets = DebugLineStrOffsets::none();
+        let debug_str_offsets = DebugStrOffsets::none();
+
+        for &version in &[2, 3, 4, 5] {
+            for &address_size in &[4, 8] {
+                for &format in &[Format::Dwarf32, Format::Dwarf64] {
+                    let encoding = Encoding {
+                        format,
+                        version,
+                        address_size,
+                    };
+                    let program = LineProgram::new(
+                        encoding,
+                        LineEncoding::default(),
+                        LineString::String(Vec::new()),
+                        LineString::String(Vec::new()),
+                        None,
+                    );
+
+                    let mut debug_line = DebugLine::from(EndianVec::new(LittleEndian));
+                    let debug_line_offset = program
+                        .write(
+                            &mut debug_line,
+                            encoding,
+                            &debug_line_str_offsets,
+                            &debug_str_offsets,
+                        )
+                        .unwrap();
+
+                    let read_debug_line = read::DebugLine::new(debug_line.slice(), LittleEndian);
+                    let read_program = read_debug_line
+                        .program(
+                            debug_line_offset,
+                            address_size,
+                            // Testing missing comp_dir/comp_name.
+                            None,
+                            None,
+                        )
+                        .unwrap();
+
+                    let dwarf = read::Dwarf::default();
+                    let mut convert_line_strings = LineStringTable::default();
+                    let mut convert_strings = StringTable::default();
+                    let convert_address = &|address| Some(Address::Constant(address));
+                    LineProgram::from(
+                        read_program,
+                        &dwarf,
+                        &mut convert_line_strings,
+                        &mut convert_strings,
+                        convert_address,
+                    )
+                    .unwrap();
+                }
+            }
+        }
+    }
+}