Merge commit '61667dedf55e3e5aa584f7ae2bd0471336b92ce9' into sync_cg_clif-2021-09-19

compiler/rustc_codegen_cranelift/src/debuginfo/object.rs

@@ -0,0 +1,85 @@
+use std::convert::{TryFrom, TryInto};
+
+use rustc_data_structures::fx::FxHashMap;
+
+use cranelift_module::FuncId;
+use cranelift_object::ObjectProduct;
+
+use object::write::{Relocation, StandardSegment};
+use object::{RelocationEncoding, SectionKind};
+
+use gimli::SectionId;
+
+use crate::debuginfo::{DebugReloc, DebugRelocName};
+
+pub(super) trait WriteDebugInfo {
+    type SectionId: Copy;
+
+    fn add_debug_section(&mut self, name: SectionId, data: Vec<u8>) -> Self::SectionId;
+    fn add_debug_reloc(
+        &mut self,
+        section_map: &FxHashMap<SectionId, Self::SectionId>,
+        from: &Self::SectionId,
+        reloc: &DebugReloc,
+    );
+}
+
+impl WriteDebugInfo for ObjectProduct {
+    type SectionId = (object::write::SectionId, object::write::SymbolId);
+
+    fn add_debug_section(
+        &mut self,
+        id: SectionId,
+        data: Vec<u8>,
+    ) -> (object::write::SectionId, object::write::SymbolId) {
+        let name = if self.object.format() == object::BinaryFormat::MachO {
+            id.name().replace('.', "__") // machO expects __debug_info instead of .debug_info
+        } else {
+            id.name().to_string()
+        }
+        .into_bytes();
+
+        let segment = self.object.segment_name(StandardSegment::Debug).to_vec();
+        // FIXME use SHT_X86_64_UNWIND for .eh_frame
+        let section_id = self.object.add_section(
+            segment,
+            name,
+            if id == SectionId::EhFrame { SectionKind::ReadOnlyData } else { SectionKind::Debug },
+        );
+        self.object
+            .section_mut(section_id)
+            .set_data(data, if id == SectionId::EhFrame { 8 } else { 1 });
+        let symbol_id = self.object.section_symbol(section_id);
+        (section_id, symbol_id)
+    }
+
+    fn add_debug_reloc(
+        &mut self,
+        section_map: &FxHashMap<SectionId, Self::SectionId>,
+        from: &Self::SectionId,
+        reloc: &DebugReloc,
+    ) {
+        let (symbol, symbol_offset) = match reloc.name {
+            DebugRelocName::Section(id) => (section_map.get(&id).unwrap().1, 0),
+            DebugRelocName::Symbol(id) => {
+                let symbol_id = self.function_symbol(FuncId::from_u32(id.try_into().unwrap()));
+                self.object
+                    .symbol_section_and_offset(symbol_id)
+                    .expect("Debug reloc for undef sym???")
+            }
+        };
+        self.object
+            .add_relocation(
+                from.0,
+                Relocation {
+                    offset: u64::from(reloc.offset),
+                    symbol,
+                    kind: reloc.kind,
+                    encoding: RelocationEncoding::Generic,
+                    size: reloc.size * 8,
+                    addend: i64::try_from(symbol_offset).unwrap() + reloc.addend,
+                },
+            )
+            .unwrap();
+    }
+}