1 use self::debug_transform_logging::dbi_log;
2 use self::refs::DebugInfoRefsMap;
3 use self::simulate::generate_simulated_dwarf;
4 use self::unit::clone_unit;
5 use crate::debug::gc::build_dependencies;
6 use crate::debug::Compilation;
7 use anyhow::Error;
8 use cranelift_codegen::isa::TargetIsa;
9 use gimli::{write, Dwarf, DwarfPackage, LittleEndian, Section, Unit, UnitSectionOffset};
10 use std::{collections::HashSet, fmt::Debug};
11 use synthetic::ModuleSyntheticUnit;
12 use thiserror::Error;
13 use wasmtime_environ::{
14     DefinedFuncIndex, ModuleTranslation, PrimaryMap, StaticModuleIndex, Tunables,
15 };
16 
17 pub use address_transform::AddressTransform;
18 
19 mod address_transform;
20 mod attr;
21 mod debug_transform_logging;
22 mod expression;
23 mod line_program;
24 mod range_info_builder;
25 mod refs;
26 mod simulate;
27 mod synthetic;
28 mod unit;
29 mod utils;
30 
31 impl<'a> Compilation<'a> {
32     fn function_frame_info(
33         &mut self,
34         module: StaticModuleIndex,
35         func: DefinedFuncIndex,
36     ) -> expression::FunctionFrameInfo<'a> {
37         let (_, func) = self.function(module, func);
38 
39         expression::FunctionFrameInfo {
40             value_ranges: &func.value_labels_ranges,
41             memory_offset: self.module_memory_offsets[module].clone(),
42         }
43     }
44 }
45 
46 pub(crate) trait Reader: gimli::Reader<Offset = usize> + Send + Sync {}
47 
48 impl<'input, Endian> Reader for gimli::EndianSlice<'input, Endian> where
49     Endian: gimli::Endianity + Send + Sync
50 {
51 }
52 
53 #[derive(Error, Debug)]
54 #[error("Debug info transform error: {0}")]
55 pub struct TransformError(&'static str);
56 
57 pub(crate) struct DebugInputContext<'a> {
58     reachable: &'a HashSet<UnitSectionOffset>,
59 }
60 
61 fn load_dwp<'data>(
62     translation: ModuleTranslation<'data>,
63     buffer: &'data [u8],
64 ) -> anyhow::Result<DwarfPackage<gimli::EndianSlice<'data, gimli::LittleEndian>>> {
65     let endian_slice = gimli::EndianSlice::new(buffer, LittleEndian);
66 
67     let dwarf_package = DwarfPackage::load(
68         |id| -> anyhow::Result<_> {
69             let slice = match id {
70                 gimli::SectionId::DebugAbbrev => {
71                     translation.debuginfo.dwarf.debug_abbrev.reader().slice()
72                 }
73                 gimli::SectionId::DebugInfo => {
74                     translation.debuginfo.dwarf.debug_info.reader().slice()
75                 }
76                 gimli::SectionId::DebugLine => {
77                     translation.debuginfo.dwarf.debug_line.reader().slice()
78                 }
79                 gimli::SectionId::DebugStr => {
80                     translation.debuginfo.dwarf.debug_str.reader().slice()
81                 }
82                 gimli::SectionId::DebugStrOffsets => translation
83                     .debuginfo
84                     .dwarf
85                     .debug_str_offsets
86                     .reader()
87                     .slice(),
88                 gimli::SectionId::DebugLoc => translation.debuginfo.debug_loc.reader().slice(),
89                 gimli::SectionId::DebugLocLists => {
90                     translation.debuginfo.debug_loclists.reader().slice()
91                 }
92                 gimli::SectionId::DebugRngLists => {
93                     translation.debuginfo.debug_rnglists.reader().slice()
94                 }
95                 gimli::SectionId::DebugTypes => {
96                     translation.debuginfo.dwarf.debug_types.reader().slice()
97                 }
98                 gimli::SectionId::DebugCuIndex => {
99                     translation.debuginfo.debug_cu_index.reader().slice()
100                 }
101                 gimli::SectionId::DebugTuIndex => {
102                     translation.debuginfo.debug_tu_index.reader().slice()
103                 }
104                 _ => &buffer,
105             };
106 
107             Ok(gimli::EndianSlice::new(slice, gimli::LittleEndian))
108         },
109         endian_slice,
110     )?;
111 
112     Ok(dwarf_package)
113 }
114 
115 /// Attempts to load a DWARF package using the passed bytes.
116 fn read_dwarf_package_from_bytes<'data>(
117     dwp_bytes: &'data [u8],
118     buffer: &'data [u8],
119     tunables: &Tunables,
120 ) -> Option<DwarfPackage<gimli::EndianSlice<'data, gimli::LittleEndian>>> {
121     let mut validator = wasmparser::Validator::new();
122     let parser = wasmparser::Parser::new(0);
123     let mut types = wasmtime_environ::ModuleTypesBuilder::new(&validator);
124     let translation =
125         match wasmtime_environ::ModuleEnvironment::new(tunables, &mut validator, &mut types)
126             .translate(parser, dwp_bytes)
127         {
128             Ok(translation) => translation,
129             Err(e) => {
130                 log::warn!("failed to parse wasm dwarf package: {e:?}");
131                 return None;
132             }
133         };
134 
135     match load_dwp(translation, buffer) {
136         Ok(package) => Some(package),
137         Err(err) => {
138             log::warn!("Failed to load Dwarf package {}", err);
139             None
140         }
141     }
142 }
143 
144 pub fn transform_dwarf(
145     isa: &dyn TargetIsa,
146     compilation: &mut Compilation<'_>,
147 ) -> Result<write::Dwarf, Error> {
148     dbi_log!("Commencing DWARF transform for {:?}", compilation);
149 
150     let mut transforms = PrimaryMap::new();
151     for (i, _) in compilation.translations.iter() {
152         transforms.push(AddressTransform::new(compilation, i));
153     }
154 
155     let buffer = Vec::new();
156 
157     let dwarf_package = compilation
158         .dwarf_package_bytes
159         .map(
160             |bytes| -> Option<DwarfPackage<gimli::EndianSlice<'_, gimli::LittleEndian>>> {
161                 read_dwarf_package_from_bytes(bytes, &buffer, compilation.tunables)
162             },
163         )
164         .flatten();
165 
166     let reachable = build_dependencies(compilation, &dwarf_package, &transforms)?.get_reachable();
167 
168     let out_encoding = gimli::Encoding {
169         format: gimli::Format::Dwarf32,
170         version: 4, // TODO: this should be configurable
171         address_size: isa.pointer_bytes(),
172     };
173     let mut out_strings = write::StringTable::default();
174     let mut out_units = write::UnitTable::default();
175 
176     let out_line_strings = write::LineStringTable::default();
177     let mut pending_di_refs = Vec::new();
178     let mut di_ref_map = DebugInfoRefsMap::new();
179     let mut vmctx_ptr_die_refs = PrimaryMap::new();
180 
181     let mut translated = HashSet::new();
182 
183     for (module, translation) in compilation.translations.iter() {
184         dbi_log!("[== Transforming CUs for module #{} ==]", module.as_u32());
185 
186         let addr_tr = &transforms[module];
187         let di = &translation.debuginfo;
188         let context = DebugInputContext {
189             reachable: &reachable,
190         };
191         let out_module_synthetic_unit = ModuleSyntheticUnit::new(
192             module,
193             compilation,
194             out_encoding,
195             &mut out_units,
196             &mut out_strings,
197         );
198         // TODO-DebugInfo-Cleanup: move the simulation code to be per-module and delete this map.
199         vmctx_ptr_die_refs.push(out_module_synthetic_unit.vmctx_ptr_die_ref());
200 
201         let mut iter = di.dwarf.debug_info.units();
202         while let Some(header) = iter.next().unwrap_or(None) {
203             let unit = di.dwarf.unit(header)?;
204 
205             let mut resolved_unit = None;
206             let mut split_dwarf = None;
207 
208             if unit.dwo_id.is_some() {
209                 if let Some(dwarf_package) = &dwarf_package {
210                     if let Some((fused, fused_dwarf)) =
211                         replace_unit_from_split_dwarf(&unit, dwarf_package, &di.dwarf)
212                     {
213                         resolved_unit = Some(fused);
214                         split_dwarf = Some(fused_dwarf);
215                     }
216                 }
217             }
218 
219             if let Some((id, ref_map, pending_refs)) = clone_unit(
220                 compilation,
221                 module,
222                 &unit,
223                 resolved_unit.as_ref(),
224                 split_dwarf.as_ref(),
225                 &context,
226                 &addr_tr,
227                 out_encoding,
228                 &out_module_synthetic_unit,
229                 &mut out_units,
230                 &mut out_strings,
231                 &mut translated,
232                 isa,
233             )? {
234                 di_ref_map.insert(&header, id, ref_map);
235                 pending_di_refs.push((id, pending_refs));
236             }
237         }
238     }
239     di_ref_map.patch(pending_di_refs.into_iter(), &mut out_units);
240 
241     generate_simulated_dwarf(
242         compilation,
243         &transforms,
244         &translated,
245         out_encoding,
246         &vmctx_ptr_die_refs,
247         &mut out_units,
248         &mut out_strings,
249         isa,
250     )?;
251 
252     Ok(write::Dwarf {
253         units: out_units,
254         line_programs: vec![],
255         line_strings: out_line_strings,
256         strings: out_strings,
257     })
258 }
259 
260 fn replace_unit_from_split_dwarf<'a>(
261     unit: &'a Unit<gimli::EndianSlice<'a, gimli::LittleEndian>, usize>,
262     dwp: &DwarfPackage<gimli::EndianSlice<'a, gimli::LittleEndian>>,
263     parent: &Dwarf<gimli::EndianSlice<'a, gimli::LittleEndian>>,
264 ) -> Option<(
265     Unit<gimli::EndianSlice<'a, gimli::LittleEndian>, usize>,
266     Dwarf<gimli::EndianSlice<'a, gimli::LittleEndian>>,
267 )> {
268     let dwo_id = unit.dwo_id?;
269     let split_unit_dwarf = dwp.find_cu(dwo_id, parent).ok()??;
270     let unit_header = split_unit_dwarf.debug_info.units().next().ok()??;
271     let mut split_unit = split_unit_dwarf.unit(unit_header).ok()?;
272     split_unit.copy_relocated_attributes(unit);
273     Some((split_unit, split_unit_dwarf))
274 }
275