wasmtime_cranelift/debug/transform/
line_program.rs

1use super::address_transform::AddressTransform;
2use super::{Reader, TransformError};
3use anyhow::{bail, Error};
4use gimli::{write, DebugLineOffset, LineEncoding, Unit};
5use wasmtime_environ::DefinedFuncIndex;
6
7#[derive(Debug)]
8enum SavedLineProgramRow {
9    Normal {
10        address: u64,
11        op_index: u64,
12        file_index: u64,
13        line: u64,
14        column: u64,
15        discriminator: u64,
16        is_stmt: bool,
17        basic_block: bool,
18        prologue_end: bool,
19        epilogue_begin: bool,
20        isa: u64,
21    },
22    EndOfSequence,
23}
24
25#[derive(Debug)]
26struct FuncRows {
27    index: DefinedFuncIndex,
28    sorted_rows: Vec<(u64, SavedLineProgramRow)>,
29}
30
31#[derive(Debug, Eq, PartialEq)]
32enum ReadLineProgramState {
33    SequenceEnded,
34    ReadSequence(DefinedFuncIndex),
35    IgnoreSequence,
36}
37
38pub(crate) fn clone_line_program<R>(
39    dwarf: &gimli::Dwarf<R>,
40    unit: &Unit<R, R::Offset>,
41    comp_name: Option<R>,
42    addr_tr: &AddressTransform,
43    out_encoding: gimli::Encoding,
44    out_strings: &mut write::StringTable,
45) -> Result<(write::LineProgram, DebugLineOffset, Vec<write::FileId>, u64), Error>
46where
47    R: Reader,
48{
49    if let Some(program) = unit.line_program.clone() {
50        let header = program.header();
51        let offset = header.offset();
52        let file_index_base = if header.version() < 5 { 1 } else { 0 };
53        assert!(header.version() <= 5, "not supported 6");
54        let line_encoding = LineEncoding {
55            minimum_instruction_length: header.minimum_instruction_length(),
56            maximum_operations_per_instruction: header.maximum_operations_per_instruction(),
57            default_is_stmt: header.default_is_stmt(),
58            line_base: header.line_base(),
59            line_range: header.line_range(),
60        };
61        let out_comp_dir = match header.directory(0) {
62            Some(comp_dir) => clone_line_string(
63                dwarf.attr_string(unit, comp_dir)?,
64                gimli::DW_FORM_string,
65                out_strings,
66            )?,
67            None => write::LineString::String(Vec::new()),
68        };
69        let out_comp_name = match comp_name {
70            Some(comp_name) => clone_line_string(comp_name, gimli::DW_FORM_strp, out_strings)?,
71            None => write::LineString::String(Vec::new()),
72        };
73
74        let mut out_program = write::LineProgram::new(
75            out_encoding,
76            line_encoding,
77            out_comp_dir,
78            out_comp_name,
79            None,
80        );
81        let mut dirs = Vec::new();
82        dirs.push(out_program.default_directory());
83        for dir_attr in header.include_directories() {
84            let dir_id = out_program.add_directory(clone_line_string(
85                dwarf.attr_string(unit, dir_attr.clone())?,
86                gimli::DW_FORM_string,
87                out_strings,
88            )?);
89            dirs.push(dir_id);
90        }
91        let mut files = Vec::new();
92        // Since we are outputting DWARF-4, perform base change.
93        let directory_index_correction = if header.version() >= 5 { 1 } else { 0 };
94        for file_entry in header.file_names() {
95            let dir_index = file_entry.directory_index() + directory_index_correction;
96            let dir_id = dirs[dir_index as usize];
97            let file_id = out_program.add_file(
98                clone_line_string(
99                    dwarf.attr_string(unit, file_entry.path_name())?,
100                    gimli::DW_FORM_string,
101                    out_strings,
102                )?,
103                dir_id,
104                None,
105            );
106            files.push(file_id);
107        }
108
109        let mut rows = program.rows();
110        let mut func_rows = Vec::new();
111        let mut saved_rows: Vec<(u64, SavedLineProgramRow)> = Vec::new();
112        let mut state = ReadLineProgramState::SequenceEnded;
113        while let Some((_header, row)) = rows.next_row()? {
114            if state == ReadLineProgramState::IgnoreSequence {
115                if row.end_sequence() {
116                    state = ReadLineProgramState::SequenceEnded;
117                }
118                continue;
119            }
120            let saved_row = if row.end_sequence() {
121                let index = match state {
122                    ReadLineProgramState::ReadSequence(index) => index,
123                    _ => panic!(),
124                };
125                saved_rows.sort_by_key(|r| r.0);
126                func_rows.push(FuncRows {
127                    index,
128                    sorted_rows: saved_rows,
129                });
130
131                saved_rows = Vec::new();
132                state = ReadLineProgramState::SequenceEnded;
133                SavedLineProgramRow::EndOfSequence
134            } else {
135                if state == ReadLineProgramState::SequenceEnded {
136                    // Discard sequences for non-existent code.
137                    if row.address() == 0 {
138                        state = ReadLineProgramState::IgnoreSequence;
139                        continue;
140                    }
141                    match addr_tr.find_func_index(row.address()) {
142                        Some(index) => {
143                            state = ReadLineProgramState::ReadSequence(index);
144                        }
145                        None => {
146                            // Some non-existent address found.
147                            state = ReadLineProgramState::IgnoreSequence;
148                            continue;
149                        }
150                    }
151                }
152                SavedLineProgramRow::Normal {
153                    address: row.address(),
154                    op_index: row.op_index(),
155                    file_index: row.file_index(),
156                    line: row.line().map(|nonzero| nonzero.get()).unwrap_or(0),
157                    column: match row.column() {
158                        gimli::ColumnType::LeftEdge => 0,
159                        gimli::ColumnType::Column(val) => val.get(),
160                    },
161                    discriminator: row.discriminator(),
162                    is_stmt: row.is_stmt(),
163                    basic_block: row.basic_block(),
164                    prologue_end: row.prologue_end(),
165                    epilogue_begin: row.epilogue_begin(),
166                    isa: row.isa(),
167                }
168            };
169            saved_rows.push((row.address(), saved_row));
170        }
171
172        for FuncRows {
173            index,
174            sorted_rows: saved_rows,
175        } in func_rows
176        {
177            let map = match addr_tr.map().get(index) {
178                Some(map) if map.len > 0 => map,
179                _ => {
180                    continue; // no code generated
181                }
182            };
183            let symbol = map.symbol;
184            let base_addr = map.offset;
185            out_program.begin_sequence(Some(write::Address::Symbol { symbol, addend: 0 }));
186            // TODO track and place function declaration line here
187            let mut last_address = None;
188            for addr_map in map.addresses.iter() {
189                let saved_row = match saved_rows.binary_search_by_key(&addr_map.wasm, |i| i.0) {
190                    Ok(i) => Some(&saved_rows[i].1),
191                    Err(i) => {
192                        if i > 0 {
193                            Some(&saved_rows[i - 1].1)
194                        } else {
195                            None
196                        }
197                    }
198                };
199                if let Some(SavedLineProgramRow::Normal {
200                    address,
201                    op_index,
202                    file_index,
203                    line,
204                    column,
205                    discriminator,
206                    is_stmt,
207                    basic_block,
208                    prologue_end,
209                    epilogue_begin,
210                    isa,
211                }) = saved_row
212                {
213                    // Ignore duplicates
214                    if Some(*address) != last_address {
215                        let address_offset = if last_address.is_none() {
216                            // Extend first entry to the function declaration
217                            // TODO use the function declaration line instead
218                            0
219                        } else {
220                            (addr_map.generated - base_addr) as u64
221                        };
222                        out_program.row().address_offset = address_offset;
223                        out_program.row().op_index = *op_index;
224                        out_program.row().file = files[(file_index - file_index_base) as usize];
225                        out_program.row().line = *line;
226                        out_program.row().column = *column;
227                        out_program.row().discriminator = *discriminator;
228                        out_program.row().is_statement = *is_stmt;
229                        out_program.row().basic_block = *basic_block;
230                        out_program.row().prologue_end = *prologue_end;
231                        out_program.row().epilogue_begin = *epilogue_begin;
232                        out_program.row().isa = *isa;
233                        out_program.generate_row();
234                        last_address = Some(*address);
235                    }
236                }
237            }
238            let end_addr = (map.offset + map.len) as u64;
239            out_program.end_sequence(end_addr);
240        }
241        Ok((out_program, offset, files, file_index_base))
242    } else {
243        Err(TransformError("Valid line program not found").into())
244    }
245}
246
247fn clone_line_string<R>(
248    value: R,
249    form: gimli::DwForm,
250    out_strings: &mut write::StringTable,
251) -> Result<write::LineString, Error>
252where
253    R: Reader,
254{
255    let content = value.to_string_lossy()?.into_owned();
256    Ok(match form {
257        gimli::DW_FORM_strp => {
258            let id = out_strings.add(content);
259            write::LineString::StringRef(id)
260        }
261        gimli::DW_FORM_string => write::LineString::String(content.into()),
262        _ => bail!("DW_FORM_line_strp or other not supported"),
263    })
264}
wasmtime_cranelift/debug/transform/line_program.rs

wasmtime_cranelift/debug/transform/
line_program.rs
