compiler/rustc_codegen_cranelift/src/debuginfo/object.rs

   1 use rustc_data_structures::fx::FxHashMap;
   2
   3 use cranelift_module::FuncId;
   4 use cranelift_object::ObjectProduct;
   5
   6 use object::write::{Relocation, StandardSegment};
   7 use object::{RelocationEncoding, SectionKind};
   8
   9 use gimli::SectionId;
  10
  11 use crate::debuginfo::{DebugReloc, DebugRelocName};
  12
  13 pub(super) trait WriteDebugInfo {
  14     type SectionId: Copy;
  15
  16     fn add_debug_section(&mut self, name: SectionId, data: Vec<u8>) -> Self::SectionId;
  17     fn add_debug_reloc(
  18         &mut self,
  19         section_map: &FxHashMap<SectionId, Self::SectionId>,
  20         from: &Self::SectionId,
  21         reloc: &DebugReloc,
  22     );
  23 }
  24
  25 impl WriteDebugInfo for ObjectProduct {
  26     type SectionId = (object::write::SectionId, object::write::SymbolId);
  27
  28     fn add_debug_section(
  29         &mut self,
  30         id: SectionId,
  31         data: Vec<u8>,
  32     ) -> (object::write::SectionId, object::write::SymbolId) {
  33         let name = if self.object.format() == object::BinaryFormat::MachO {
  34             id.name().replace('.', "__") // machO expects __debug_info instead of .debug_info
  35         } else {
  36             id.name().to_string()
  37         }
  38         .into_bytes();
  39
  40         let segment = self.object.segment_name(StandardSegment::Debug).to_vec();
  41         // FIXME use SHT_X86_64_UNWIND for .eh_frame
  42         let section_id = self.object.add_section(
  43             segment,
  44             name,
  45             if id == SectionId::EhFrame { SectionKind::ReadOnlyData } else { SectionKind::Debug },
  46         );
  47         self.object
  48             .section_mut(section_id)
  49             .set_data(data, if id == SectionId::EhFrame { 8 } else { 1 });
  50         let symbol_id = self.object.section_symbol(section_id);
  51         (section_id, symbol_id)
  52     }
  53
  54     fn add_debug_reloc(
  55         &mut self,
  56         section_map: &FxHashMap<SectionId, Self::SectionId>,
  57         from: &Self::SectionId,
  58         reloc: &DebugReloc,
  59     ) {
  60         let (symbol, symbol_offset) = match reloc.name {
  61             DebugRelocName::Section(id) => (section_map.get(&id).unwrap().1, 0),
  62             DebugRelocName::Symbol(id) => {
  63                 let symbol_id = self.function_symbol(FuncId::from_u32(id.try_into().unwrap()));
  64                 self.object
  65                     .symbol_section_and_offset(symbol_id)
  66                     .expect("Debug reloc for undef sym???")
  67             }
  68         };
  69         self.object
  70             .add_relocation(
  71                 from.0,
  72                 Relocation {
  73                     offset: u64::from(reloc.offset),
  74                     symbol,
  75                     kind: reloc.kind,
  76                     encoding: RelocationEncoding::Generic,
  77                     size: reloc.size * 8,
  78                     addend: i64::try_from(symbol_offset).unwrap() + reloc.addend,
  79                 },
  80             )
  81             .unwrap();
  82     }
  83 }