1 //! Write the debuginfo into an object file. 2 3 use cranelift_object::ObjectProduct; 4 use rustc_data_structures::fx::FxHashMap; 5 6 use gimli::write::{Address, AttributeValue, EndianVec, Result, Sections, Writer}; 7 use gimli::{RunTimeEndian, SectionId}; 8 9 use super::object::WriteDebugInfo; 10 use super::DebugContext; 11 12 impl DebugContext { emit(&mut self, product: &mut ObjectProduct)13 pub(crate) fn emit(&mut self, product: &mut ObjectProduct) { 14 let unit_range_list_id = self.dwarf.unit.ranges.add(self.unit_range_list.clone()); 15 let root = self.dwarf.unit.root(); 16 let root = self.dwarf.unit.get_mut(root); 17 root.set(gimli::DW_AT_ranges, AttributeValue::RangeListRef(unit_range_list_id)); 18 19 let mut sections = Sections::new(WriterRelocate::new(self.endian)); 20 self.dwarf.write(&mut sections).unwrap(); 21 22 let mut section_map = FxHashMap::default(); 23 let _: Result<()> = sections.for_each_mut(|id, section| { 24 if !section.writer.slice().is_empty() { 25 let section_id = product.add_debug_section(id, section.writer.take()); 26 section_map.insert(id, section_id); 27 } 28 Ok(()) 29 }); 30 31 let _: Result<()> = sections.for_each(|id, section| { 32 if let Some(section_id) = section_map.get(&id) { 33 for reloc in §ion.relocs { 34 product.add_debug_reloc(§ion_map, section_id, reloc); 35 } 36 } 37 Ok(()) 38 }); 39 } 40 } 41 42 #[derive(Clone)] 43 pub(crate) struct DebugReloc { 44 pub(crate) offset: u32, 45 pub(crate) size: u8, 46 pub(crate) name: DebugRelocName, 47 pub(crate) addend: i64, 48 pub(crate) kind: object::RelocationKind, 49 } 50 51 #[derive(Clone)] 52 pub(crate) enum DebugRelocName { 53 Section(SectionId), 54 Symbol(usize), 55 } 56 57 /// A [`Writer`] that collects all necessary relocations. 58 #[derive(Clone)] 59 pub(super) struct WriterRelocate { 60 pub(super) relocs: Vec<DebugReloc>, 61 pub(super) writer: EndianVec<RunTimeEndian>, 62 } 63 64 impl WriterRelocate { new(endian: RunTimeEndian) -> Self65 pub(super) fn new(endian: RunTimeEndian) -> Self { 66 WriterRelocate { relocs: Vec::new(), writer: EndianVec::new(endian) } 67 } 68 69 /// Perform the collected relocations to be usable for JIT usage. 70 #[cfg(all(feature = "jit", not(windows)))] relocate_for_jit(mut self, jit_module: &cranelift_jit::JITModule) -> Vec<u8>71 pub(super) fn relocate_for_jit(mut self, jit_module: &cranelift_jit::JITModule) -> Vec<u8> { 72 for reloc in self.relocs.drain(..) { 73 match reloc.name { 74 super::DebugRelocName::Section(_) => unreachable!(), 75 super::DebugRelocName::Symbol(sym) => { 76 let addr = jit_module.get_finalized_function( 77 cranelift_module::FuncId::from_u32(sym.try_into().unwrap()), 78 ); 79 let val = (addr as u64 as i64 + reloc.addend) as u64; 80 self.writer.write_udata_at(reloc.offset as usize, val, reloc.size).unwrap(); 81 } 82 } 83 } 84 self.writer.into_vec() 85 } 86 } 87 88 impl Writer for WriterRelocate { 89 type Endian = RunTimeEndian; 90 endian(&self) -> Self::Endian91 fn endian(&self) -> Self::Endian { 92 self.writer.endian() 93 } 94 len(&self) -> usize95 fn len(&self) -> usize { 96 self.writer.len() 97 } 98 write(&mut self, bytes: &[u8]) -> Result<()>99 fn write(&mut self, bytes: &[u8]) -> Result<()> { 100 self.writer.write(bytes) 101 } 102 write_at(&mut self, offset: usize, bytes: &[u8]) -> Result<()>103 fn write_at(&mut self, offset: usize, bytes: &[u8]) -> Result<()> { 104 self.writer.write_at(offset, bytes) 105 } 106 write_address(&mut self, address: Address, size: u8) -> Result<()>107 fn write_address(&mut self, address: Address, size: u8) -> Result<()> { 108 match address { 109 Address::Constant(val) => self.write_udata(val, size), 110 Address::Symbol { symbol, addend } => { 111 let offset = self.len() as u64; 112 self.relocs.push(DebugReloc { 113 offset: offset as u32, 114 size, 115 name: DebugRelocName::Symbol(symbol), 116 addend, 117 kind: object::RelocationKind::Absolute, 118 }); 119 self.write_udata(0, size) 120 } 121 } 122 } 123 write_offset(&mut self, val: usize, section: SectionId, size: u8) -> Result<()>124 fn write_offset(&mut self, val: usize, section: SectionId, size: u8) -> Result<()> { 125 let offset = self.len() as u32; 126 self.relocs.push(DebugReloc { 127 offset, 128 size, 129 name: DebugRelocName::Section(section), 130 addend: val as i64, 131 kind: object::RelocationKind::Absolute, 132 }); 133 self.write_udata(0, size) 134 } 135 write_offset_at( &mut self, offset: usize, val: usize, section: SectionId, size: u8, ) -> Result<()>136 fn write_offset_at( 137 &mut self, 138 offset: usize, 139 val: usize, 140 section: SectionId, 141 size: u8, 142 ) -> Result<()> { 143 self.relocs.push(DebugReloc { 144 offset: offset as u32, 145 size, 146 name: DebugRelocName::Section(section), 147 addend: val as i64, 148 kind: object::RelocationKind::Absolute, 149 }); 150 self.write_udata_at(offset, 0, size) 151 } 152 write_eh_pointer(&mut self, address: Address, eh_pe: gimli::DwEhPe, size: u8) -> Result<()>153 fn write_eh_pointer(&mut self, address: Address, eh_pe: gimli::DwEhPe, size: u8) -> Result<()> { 154 match address { 155 // Address::Constant arm copied from gimli 156 Address::Constant(val) => { 157 // Indirect doesn't matter here. 158 let val = match eh_pe.application() { 159 gimli::DW_EH_PE_absptr => val, 160 gimli::DW_EH_PE_pcrel => { 161 // FIXME better handling of sign 162 let offset = self.len() as u64; 163 offset.wrapping_sub(val) 164 } 165 _ => { 166 return Err(gimli::write::Error::UnsupportedPointerEncoding(eh_pe)); 167 } 168 }; 169 self.write_eh_pointer_data(val, eh_pe.format(), size) 170 } 171 Address::Symbol { symbol, addend } => match eh_pe.application() { 172 gimli::DW_EH_PE_pcrel => { 173 let size = match eh_pe.format() { 174 gimli::DW_EH_PE_sdata4 => 4, 175 _ => return Err(gimli::write::Error::UnsupportedPointerEncoding(eh_pe)), 176 }; 177 self.relocs.push(DebugReloc { 178 offset: self.len() as u32, 179 size, 180 name: DebugRelocName::Symbol(symbol), 181 addend, 182 kind: object::RelocationKind::Relative, 183 }); 184 self.write_udata(0, size) 185 } 186 _ => Err(gimli::write::Error::UnsupportedPointerEncoding(eh_pe)), 187 }, 188 } 189 } 190 } 191