Add 'compiler/rustc_codegen_cranelift/' from commit '793d26047f'

git-subtree-dir: compiler/rustc_codegen_cranelift
git-subtree-mainline: cf798c1ec6
git-subtree-split: 793d26047f

compiler/rustc_codegen_cranelift/src/debuginfo/mod.rs

@@ -0,0 +1,487 @@
+//! Handling of everything related to debuginfo.
+
+mod emit;
+mod line_info;
+mod unwind;
+
+use crate::prelude::*;
+
+use rustc_index::vec::IndexVec;
+
+use cranelift_codegen::entity::EntityRef;
+use cranelift_codegen::ir::{StackSlots, ValueLabel, ValueLoc};
+use cranelift_codegen::isa::TargetIsa;
+use cranelift_codegen::ValueLocRange;
+
+use gimli::write::{
+    Address, AttributeValue, DwarfUnit, Expression, LineProgram, LineString, Location,
+    LocationList, Range, RangeList, UnitEntryId,
+};
+use gimli::{Encoding, Format, LineEncoding, RunTimeEndian, X86_64};
+
+pub(crate) use emit::{DebugReloc, DebugRelocName};
+pub(crate) use unwind::UnwindContext;
+
+fn target_endian(tcx: TyCtxt<'_>) -> RunTimeEndian {
+    use rustc_target::abi::Endian;
+
+    match tcx.data_layout.endian {
+        Endian::Big => RunTimeEndian::Big,
+        Endian::Little => RunTimeEndian::Little,
+    }
+}
+
+pub(crate) struct DebugContext<'tcx> {
+    tcx: TyCtxt<'tcx>,
+
+    endian: RunTimeEndian,
+
+    dwarf: DwarfUnit,
+    unit_range_list: RangeList,
+
+    clif_types: FxHashMap<Type, UnitEntryId>,
+    types: FxHashMap<Ty<'tcx>, UnitEntryId>,
+}
+
+impl<'tcx> DebugContext<'tcx> {
+    pub(crate) fn new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa) -> Self {
+        let encoding = Encoding {
+            format: Format::Dwarf32,
+            // TODO: this should be configurable
+            // macOS doesn't seem to support DWARF > 3
+            // 5 version is required for md5 file hash
+            version: if tcx.sess.target.options.is_like_osx {
+                3
+            } else {
+                // FIXME change to version 5 once the gdb and lldb shipping with the latest debian
+                // support it.
+                4
+            },
+            address_size: isa.frontend_config().pointer_bytes(),
+        };
+
+        let mut dwarf = DwarfUnit::new(encoding);
+
+        // FIXME: how to get version when building out of tree?
+        // Normally this would use option_env!("CFG_VERSION").
+        let producer = format!("cg_clif (rustc {})", "unknown version");
+        let comp_dir = tcx.sess.working_dir.0.to_string_lossy().into_owned();
+        let (name, file_info) = match tcx.sess.local_crate_source_file.clone() {
+            Some(path) => {
+                let name = path.to_string_lossy().into_owned();
+                (name, None)
+            }
+            None => (tcx.crate_name(LOCAL_CRATE).to_string(), None),
+        };
+
+        let mut line_program = LineProgram::new(
+            encoding,
+            LineEncoding::default(),
+            LineString::new(comp_dir.as_bytes(), encoding, &mut dwarf.line_strings),
+            LineString::new(name.as_bytes(), encoding, &mut dwarf.line_strings),
+            file_info,
+        );
+        line_program.file_has_md5 = file_info.is_some();
+
+        dwarf.unit.line_program = line_program;
+
+        {
+            let name = dwarf.strings.add(name);
+            let comp_dir = dwarf.strings.add(comp_dir);
+
+            let root = dwarf.unit.root();
+            let root = dwarf.unit.get_mut(root);
+            root.set(
+                gimli::DW_AT_producer,
+                AttributeValue::StringRef(dwarf.strings.add(producer)),
+            );
+            root.set(
+                gimli::DW_AT_language,
+                AttributeValue::Language(gimli::DW_LANG_Rust),
+            );
+            root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
+            root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
+            root.set(
+                gimli::DW_AT_low_pc,
+                AttributeValue::Address(Address::Constant(0)),
+            );
+        }
+
+        DebugContext {
+            tcx,
+
+            endian: target_endian(tcx),
+
+            dwarf,
+            unit_range_list: RangeList(Vec::new()),
+
+            clif_types: FxHashMap::default(),
+            types: FxHashMap::default(),
+        }
+    }
+
+    fn dwarf_ty_for_clif_ty(&mut self, ty: Type) -> UnitEntryId {
+        if let Some(type_id) = self.clif_types.get(&ty) {
+            return *type_id;
+        }
+
+        let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
+
+        let primitive = |dwarf: &mut DwarfUnit, ate| {
+            let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
+            let type_entry = dwarf.unit.get_mut(type_id);
+            type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
+            type_id
+        };
+
+        let type_id = if ty.is_bool() {
+            primitive(&mut self.dwarf, gimli::DW_ATE_boolean)
+        } else if ty.is_int() {
+            primitive(&mut self.dwarf, gimli::DW_ATE_address)
+        } else if ty.is_float() {
+            primitive(&mut self.dwarf, gimli::DW_ATE_float)
+        } else {
+            new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type)
+        };
+
+        let type_entry = self.dwarf.unit.get_mut(type_id);
+        type_entry.set(
+            gimli::DW_AT_name,
+            AttributeValue::String(format!("{}", ty).replace('i', "u").into_bytes()),
+        );
+        type_entry.set(
+            gimli::DW_AT_byte_size,
+            AttributeValue::Udata(u64::from(ty.bytes())),
+        );
+
+        type_id
+    }
+
+    fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
+        if let Some(type_id) = self.types.get(ty) {
+            return *type_id;
+        }
+
+        let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
+
+        let primitive = |dwarf: &mut DwarfUnit, ate| {
+            let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
+            let type_entry = dwarf.unit.get_mut(type_id);
+            type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
+            type_id
+        };
+
+        let name = format!("{}", ty);
+        let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
+
+        let type_id = match ty.kind() {
+            ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
+            ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
+            ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
+            ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
+            ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
+            ty::Ref(_, pointee_ty, _mutbl)
+            | ty::RawPtr(ty::TypeAndMut {
+                ty: pointee_ty,
+                mutbl: _mutbl,
+            }) => {
+                let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
+
+                // Ensure that type is inserted before recursing to avoid duplicates
+                self.types.insert(ty, type_id);
+
+                let pointee = self.dwarf_ty(pointee_ty);
+
+                let type_entry = self.dwarf.unit.get_mut(type_id);
+
+                //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
+                type_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(pointee));
+
+                type_id
+            }
+            ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
+                let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
+
+                // Ensure that type is inserted before recursing to avoid duplicates
+                self.types.insert(ty, type_id);
+
+                let variant = adt_def.non_enum_variant();
+
+                for (field_idx, field_def) in variant.fields.iter().enumerate() {
+                    let field_offset = layout.fields.offset(field_idx);
+                    let field_layout = layout
+                        .field(
+                            &layout::LayoutCx {
+                                tcx: self.tcx,
+                                param_env: ParamEnv::reveal_all(),
+                            },
+                            field_idx,
+                        )
+                        .unwrap();
+
+                    let field_type = self.dwarf_ty(field_layout.ty);
+
+                    let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
+                    let field_entry = self.dwarf.unit.get_mut(field_id);
+
+                    field_entry.set(
+                        gimli::DW_AT_name,
+                        AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()),
+                    );
+                    field_entry.set(
+                        gimli::DW_AT_data_member_location,
+                        AttributeValue::Udata(field_offset.bytes()),
+                    );
+                    field_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(field_type));
+                }
+
+                type_id
+            }
+            _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
+        };
+
+        let type_entry = self.dwarf.unit.get_mut(type_id);
+
+        type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
+        type_entry.set(
+            gimli::DW_AT_byte_size,
+            AttributeValue::Udata(layout.size.bytes()),
+        );
+
+        self.types.insert(ty, type_id);
+
+        type_id
+    }
+
+    fn define_local(&mut self, scope: UnitEntryId, name: String, ty: Ty<'tcx>) -> UnitEntryId {
+        let dw_ty = self.dwarf_ty(ty);
+
+        let var_id = self.dwarf.unit.add(scope, gimli::DW_TAG_variable);
+        let var_entry = self.dwarf.unit.get_mut(var_id);
+
+        var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
+        var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
+
+        var_id
+    }
+
+    pub(crate) fn define_function(
+        &mut self,
+        instance: Instance<'tcx>,
+        func_id: FuncId,
+        name: &str,
+        isa: &dyn TargetIsa,
+        context: &Context,
+        source_info_set: &indexmap::IndexSet<SourceInfo>,
+        local_map: IndexVec<mir::Local, CPlace<'tcx>>,
+    ) {
+        let symbol = func_id.as_u32() as usize;
+        let mir = self.tcx.instance_mir(instance.def);
+
+        // FIXME: add to appropriate scope instead of root
+        let scope = self.dwarf.unit.root();
+
+        let entry_id = self.dwarf.unit.add(scope, gimli::DW_TAG_subprogram);
+        let entry = self.dwarf.unit.get_mut(entry_id);
+        let name_id = self.dwarf.strings.add(name);
+        // Gdb requires DW_AT_name. Otherwise the DW_TAG_subprogram is skipped.
+        entry.set(gimli::DW_AT_name, AttributeValue::StringRef(name_id));
+        entry.set(
+            gimli::DW_AT_linkage_name,
+            AttributeValue::StringRef(name_id),
+        );
+
+        let end =
+            self.create_debug_lines(isa, symbol, entry_id, context, mir.span, source_info_set);
+
+        self.unit_range_list.0.push(Range::StartLength {
+            begin: Address::Symbol { symbol, addend: 0 },
+            length: u64::from(end),
+        });
+
+        if isa.get_mach_backend().is_some() {
+            return; // Not yet implemented for the AArch64 backend.
+        }
+
+        let func_entry = self.dwarf.unit.get_mut(entry_id);
+        // Gdb requires both DW_AT_low_pc and DW_AT_high_pc. Otherwise the DW_TAG_subprogram is skipped.
+        func_entry.set(
+            gimli::DW_AT_low_pc,
+            AttributeValue::Address(Address::Symbol { symbol, addend: 0 }),
+        );
+        // Using Udata for DW_AT_high_pc requires at least DWARF4
+        func_entry.set(gimli::DW_AT_high_pc, AttributeValue::Udata(u64::from(end)));
+
+        // FIXME Remove once actual debuginfo for locals works.
+        for (i, (param, &val)) in context
+            .func
+            .signature
+            .params
+            .iter()
+            .zip(
+                context
+                    .func
+                    .dfg
+                    .block_params(context.func.layout.entry_block().unwrap()),
+            )
+            .enumerate()
+        {
+            use cranelift_codegen::ir::ArgumentPurpose;
+            let base_name = match param.purpose {
+                ArgumentPurpose::Normal => "arg",
+                ArgumentPurpose::StructArgument(_) => "struct_arg",
+                ArgumentPurpose::StructReturn => "sret",
+                ArgumentPurpose::Link
+                | ArgumentPurpose::FramePointer
+                | ArgumentPurpose::CalleeSaved => continue,
+                ArgumentPurpose::VMContext
+                | ArgumentPurpose::SignatureId
+                | ArgumentPurpose::CallerTLS
+                | ArgumentPurpose::CalleeTLS
+                | ArgumentPurpose::StackLimit => unreachable!(),
+            };
+            let name = format!("{}{}", base_name, i);
+
+            let dw_ty = self.dwarf_ty_for_clif_ty(param.value_type);
+            let loc =
+                translate_loc(isa, context.func.locations[val], &context.func.stack_slots).unwrap();
+
+            let arg_id = self
+                .dwarf
+                .unit
+                .add(entry_id, gimli::DW_TAG_formal_parameter);
+            let var_entry = self.dwarf.unit.get_mut(arg_id);
+
+            var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
+            var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
+            var_entry.set(gimli::DW_AT_location, AttributeValue::Exprloc(loc));
+        }
+
+        // FIXME make it more reliable and implement scopes before re-enabling this.
+        if false {
+            let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
+
+            for (local, _local_decl) in mir.local_decls.iter_enumerated() {
+                let ty = self.tcx.subst_and_normalize_erasing_regions(
+                    instance.substs,
+                    ty::ParamEnv::reveal_all(),
+                    &mir.local_decls[local].ty,
+                );
+                let var_id = self.define_local(entry_id, format!("{:?}", local), ty);
+
+                let location = place_location(
+                    self,
+                    isa,
+                    symbol,
+                    context,
+                    &local_map,
+                    &value_labels_ranges,
+                    Place {
+                        local,
+                        projection: ty::List::empty(),
+                    },
+                );
+
+                let var_entry = self.dwarf.unit.get_mut(var_id);
+                var_entry.set(gimli::DW_AT_location, location);
+            }
+        }
+
+        // FIXME create locals for all entries in mir.var_debug_info
+    }
+}
+
+fn place_location<'tcx>(
+    debug_context: &mut DebugContext<'tcx>,
+    isa: &dyn TargetIsa,
+    symbol: usize,
+    context: &Context,
+    local_map: &IndexVec<mir::Local, CPlace<'tcx>>,
+    #[allow(rustc::default_hash_types)] value_labels_ranges: &std::collections::HashMap<
+        ValueLabel,
+        Vec<ValueLocRange>,
+    >,
+    place: Place<'tcx>,
+) -> AttributeValue {
+    assert!(place.projection.is_empty()); // FIXME implement them
+
+    match local_map[place.local].inner() {
+        CPlaceInner::Var(_local, var) => {
+            let value_label = cranelift_codegen::ir::ValueLabel::new(var.index());
+            if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
+                let loc_list = LocationList(
+                    value_loc_ranges
+                        .iter()
+                        .map(|value_loc_range| Location::StartEnd {
+                            begin: Address::Symbol {
+                                symbol,
+                                addend: i64::from(value_loc_range.start),
+                            },
+                            end: Address::Symbol {
+                                symbol,
+                                addend: i64::from(value_loc_range.end),
+                            },
+                            data: translate_loc(
+                                isa,
+                                value_loc_range.loc,
+                                &context.func.stack_slots,
+                            )
+                            .unwrap(),
+                        })
+                        .collect(),
+                );
+                let loc_list_id = debug_context.dwarf.unit.locations.add(loc_list);
+
+                AttributeValue::LocationListRef(loc_list_id)
+            } else {
+                // FIXME set value labels for unused locals
+
+                AttributeValue::Exprloc(Expression::new())
+            }
+        }
+        CPlaceInner::VarPair(_, _, _) => {
+            // FIXME implement this
+
+            AttributeValue::Exprloc(Expression::new())
+        }
+        CPlaceInner::VarLane(_, _, _) => {
+            // FIXME implement this
+
+            AttributeValue::Exprloc(Expression::new())
+        }
+        CPlaceInner::Addr(_, _) => {
+            // FIXME implement this (used by arguments and returns)
+
+            AttributeValue::Exprloc(Expression::new())
+
+            // For PointerBase::Stack:
+            //AttributeValue::Exprloc(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap())
+        }
+    }
+}
+
+// Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
+fn translate_loc(
+    isa: &dyn TargetIsa,
+    loc: ValueLoc,
+    stack_slots: &StackSlots,
+) -> Option<Expression> {
+    match loc {
+        ValueLoc::Reg(reg) => {
+            let machine_reg = isa.map_dwarf_register(reg).unwrap();
+            let mut expr = Expression::new();
+            expr.op_reg(gimli::Register(machine_reg));
+            Some(expr)
+        }
+        ValueLoc::Stack(ss) => {
+            if let Some(ss_offset) = stack_slots[ss].offset {
+                let mut expr = Expression::new();
+                expr.op_breg(X86_64::RBP, i64::from(ss_offset) + 16);
+                Some(expr)
+            } else {
+                None
+            }
+        }
+        _ => None,
+    }
+}