Add cranelift-object

cranelift/Cargo.toml

@@ -29,6 +29,7 @@ cranelift-native = { path = "cranelift-native", version = "0.42.0" }
 cranelift-filetests = { path = "cranelift-filetests", version = "0.42.0" }
 cranelift-module = { path = "cranelift-module", version = "0.42.0" }
 cranelift-faerie = { path = "cranelift-faerie", version = "0.42.0" }
+cranelift-object = { path = "cranelift-object", version = "0.42.0" }
 cranelift-simplejit = { path = "cranelift-simplejit", version = "0.42.0" }
 cranelift-preopt = { path = "cranelift-preopt", version = "0.42.0" }
 cranelift = { path = "cranelift-umbrella", version = "0.42.0" }

cranelift/codegen/src/ir/libcall.rs

@@ -18,7 +18,7 @@ use serde::{Deserialize, Serialize};
 /// convention in the embedding VM's runtime library.
 ///
 /// This list is likely to grow over time.
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 #[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
 pub enum LibCall {
     /// probe for stack overflow. These are emitted for functions which need

cranelift/faerie/src/backend.rs

@@ -8,8 +8,8 @@ use cranelift_codegen::binemit::{
 use cranelift_codegen::isa::TargetIsa;
 use cranelift_codegen::{self, binemit, ir};
 use cranelift_module::{
-    Backend, DataContext, DataDescription, Init, Linkage, ModuleError, ModuleNamespace,
+    Backend, DataContext, DataDescription, DataId, FuncId, Init, Linkage, ModuleError,
-    ModuleResult,
+    ModuleNamespace, ModuleResult,
 };
 use faerie;
 use failure::Error;
@@ -123,13 +123,20 @@ impl Backend for FaerieBackend {
         &*self.isa
     }
 
-    fn declare_function(&mut self, name: &str, linkage: Linkage) {
+    fn declare_function(&mut self, _id: FuncId, name: &str, linkage: Linkage) {
         self.artifact
             .declare(name, translate_function_linkage(linkage))
             .expect("inconsistent declarations");
     }
 
-    fn declare_data(&mut self, name: &str, linkage: Linkage, writable: bool, align: Option<u8>) {
+    fn declare_data(
+        &mut self,
+        _id: DataId,
+        name: &str,
+        linkage: Linkage,
+        writable: bool,
+        align: Option<u8>,
+    ) {
         self.artifact
             .declare(name, translate_data_linkage(linkage, writable, align))
             .expect("inconsistent declarations");
@@ -137,6 +144,7 @@ impl Backend for FaerieBackend {
 
     fn define_function(
         &mut self,
+        _id: FuncId,
         name: &str,
         ctx: &cranelift_codegen::Context,
         namespace: &ModuleNamespace<Self>,
@@ -194,6 +202,7 @@ impl Backend for FaerieBackend {
 
     fn define_data(
         &mut self,
+        _id: DataId,
         name: &str,
         _writable: bool,
         _align: Option<u8>,
@@ -274,6 +283,7 @@ impl Backend for FaerieBackend {
 
     fn finalize_function(
         &mut self,
+        _id: FuncId,
         _func: &FaerieCompiledFunction,
         _namespace: &ModuleNamespace<Self>,
     ) {
@@ -284,7 +294,12 @@ impl Backend for FaerieBackend {
         // Nothing to do.
     }
 
-    fn finalize_data(&mut self, _data: &FaerieCompiledData, _namespace: &ModuleNamespace<Self>) {
+    fn finalize_data(
+        &mut self,
+        _id: DataId,
+        _data: &FaerieCompiledData,
+        _namespace: &ModuleNamespace<Self>,
+    ) {
         // Nothing to do.
     }
 

cranelift/module/src/backend.rs

@@ -1,6 +1,8 @@
 //! Defines the `Backend` trait.
 
 use crate::DataContext;
+use crate::DataId;
+use crate::FuncId;
 use crate::Linkage;
 use crate::ModuleNamespace;
 use crate::ModuleResult;
@@ -56,16 +58,24 @@ where
     fn isa(&self) -> &dyn TargetIsa;
 
     /// Declare a function.
-    fn declare_function(&mut self, name: &str, linkage: Linkage);
+    fn declare_function(&mut self, id: FuncId, name: &str, linkage: Linkage);
 
     /// Declare a data object.
-    fn declare_data(&mut self, name: &str, linkage: Linkage, writable: bool, align: Option<u8>);
+    fn declare_data(
+        &mut self,
+        id: DataId,
+        name: &str,
+        linkage: Linkage,
+        writable: bool,
+        align: Option<u8>,
+    );
 
     /// Define a function, producing the function body from the given `Context`.
     ///
     /// Functions must be declared before being defined.
     fn define_function(
         &mut self,
+        id: FuncId,
         name: &str,
         ctx: &Context,
         namespace: &ModuleNamespace<Self>,
@@ -77,6 +87,7 @@ where
     /// Data objects must be declared before being defined.
     fn define_data(
         &mut self,
+        id: DataId,
         name: &str,
         writable: bool,
         align: Option<u8>,
@@ -107,6 +118,7 @@ where
     /// and `Export` entities referenced to be defined.
     fn finalize_function(
         &mut self,
+        id: FuncId,
         func: &Self::CompiledFunction,
         namespace: &ModuleNamespace<Self>,
     ) -> Self::FinalizedFunction;
@@ -118,6 +130,7 @@ where
     /// `Local` and `Export` entities referenced to be defined.
     fn finalize_data(
         &mut self,
+        id: DataId,
         data: &Self::CompiledData,
         namespace: &ModuleNamespace<Self>,
     ) -> Self::FinalizedData;

cranelift/module/src/module.rs

@@ -224,26 +224,32 @@ impl<B> ModuleContents<B>
 where
     B: Backend,
 {
-    fn get_function_info(&self, name: &ir::ExternalName) -> &ModuleFunction<B> {
+    fn get_function_id(&self, name: &ir::ExternalName) -> FuncId {
         if let ir::ExternalName::User { namespace, index } = *name {
             debug_assert_eq!(namespace, 0);
-            let func = FuncId::from_u32(index);
+            FuncId::from_u32(index)
-            &self.functions[func]
         } else {
             panic!("unexpected ExternalName kind {}", name)
         }
     }
 
-    /// Get the `DataDeclaration` for the function named by `name`.
+    fn get_data_id(&self, name: &ir::ExternalName) -> DataId {
-    fn get_data_info(&self, name: &ir::ExternalName) -> &ModuleData<B> {
         if let ir::ExternalName::User { namespace, index } = *name {
             debug_assert_eq!(namespace, 1);
-            let data = DataId::from_u32(index);
+            DataId::from_u32(index)
-            &self.data_objects[data]
         } else {
             panic!("unexpected ExternalName kind {}", name)
         }
     }
+
+    fn get_function_info(&self, name: &ir::ExternalName) -> &ModuleFunction<B> {
+        &self.functions[self.get_function_id(name)]
+    }
+
+    /// Get the `DataDeclaration` for the function named by `name`.
+    fn get_data_info(&self, name: &ir::ExternalName) -> &ModuleData<B> {
+        &self.data_objects[self.get_data_id(name)]
+    }
 }
 
 /// This provides a view to the state of a module which allows `ir::ExternalName`s to be translated
@@ -259,12 +265,22 @@ impl<'a, B> ModuleNamespace<'a, B>
 where
     B: Backend,
 {
+    /// Get the `FuncId` for the function named by `name`.
+    pub fn get_function_id(&self, name: &ir::ExternalName) -> FuncId {
+        self.contents.get_function_id(name)
+    }
+
+    /// Get the `DataId` for the data object named by `name`.
+    pub fn get_data_id(&self, name: &ir::ExternalName) -> DataId {
+        self.contents.get_data_id(name)
+    }
+
     /// Get the `FunctionDeclaration` for the function named by `name`.
     pub fn get_function_decl(&self, name: &ir::ExternalName) -> &FunctionDeclaration {
         &self.contents.get_function_info(name).decl
     }
 
-    /// Get the `DataDeclaration` for the function named by `name`.
+    /// Get the `DataDeclaration` for the data object named by `name`.
     pub fn get_data_decl(&self, name: &ir::ExternalName) -> &DataDeclaration {
         &self.contents.get_data_info(name).decl
     }
@@ -407,7 +423,8 @@ where
                 FuncOrDataId::Func(id) => {
                     let existing = &mut self.contents.functions[id];
                     existing.merge(linkage, signature)?;
-                    self.backend.declare_function(name, existing.decl.linkage);
+                    self.backend
+                        .declare_function(id, name, existing.decl.linkage);
                     Ok(id)
                 }
                 FuncOrDataId::Data(..) => {
@@ -424,7 +441,7 @@ where
                     compiled: None,
                 });
                 entry.insert(FuncOrDataId::Func(id));
-                self.backend.declare_function(name, linkage);
+                self.backend.declare_function(id, name, linkage);
                 Ok(id)
             }
         }
@@ -451,6 +468,7 @@ where
                     let existing = &mut self.contents.data_objects[id];
                     existing.merge(linkage, writable, align);
                     self.backend.declare_data(
+                        id,
                         name,
                         existing.decl.linkage,
                         existing.decl.writable,
@@ -474,7 +492,8 @@ where
                     compiled: None,
                 });
                 entry.insert(FuncOrDataId::Data(id));
-                self.backend.declare_data(name, linkage, writable, align);
+                self.backend
+                    .declare_data(id, name, linkage, writable, align);
                 Ok(id)
             }
         }
@@ -536,7 +555,6 @@ where
             );
             ModuleError::Compilation(e)
         })?;
-
         let info = &self.contents.functions[func];
         if info.compiled.is_some() {
             return Err(ModuleError::DuplicateDefinition(info.decl.name.clone()));
@@ -546,6 +564,7 @@ where
         }
 
         let compiled = Some(self.backend.define_function(
+            func,
             &info.decl.name,
             ctx,
             &ModuleNamespace::<B> {
@@ -570,6 +589,7 @@ where
                 return Err(ModuleError::InvalidImportDefinition(info.decl.name.clone()));
             }
             Some(self.backend.define_data(
+                data,
                 &info.decl.name,
                 info.decl.writable,
                 info.decl.align,
@@ -638,6 +658,7 @@ where
             let info = &self.contents.functions[func];
             debug_assert!(info.decl.linkage.is_definable());
             self.backend.finalize_function(
+                func,
                 info.compiled
                     .as_ref()
                     .expect("function must be compiled before it can be finalized"),
@@ -650,6 +671,7 @@ where
             let info = &self.contents.data_objects[data];
             debug_assert!(info.decl.linkage.is_definable());
             self.backend.finalize_data(
+                data,
                 info.compiled
                     .as_ref()
                     .expect("data object must be compiled before it can be finalized"),

cranelift/object/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "cranelift-object"
+version = "0.42.0"
+authors = ["The Cranelift Project Developers"]
+description = "Emit Cranelift output to native object files with `object`"
+repository = "https://github.com/CraneStation/cranelift"
+documentation = "https://cranelift.readthedocs.io/"
+license = "Apache-2.0 WITH LLVM-exception"
+readme = "README.md"
+edition = "2018"
+
+[dependencies]
+cranelift-codegen = { path = "../cranelift-codegen", version = "0.42.0" }
+cranelift-module = { path = "../cranelift-module", version = "0.42.0" }
+object = { version = "0.14.0", default-features = false, features = ["write"] }
+target-lexicon = "0.8.1"
+
+[badges]
+maintenance = { status = "experimental" }
+travis-ci = { repository = "CraneStation/cranelift" }

cranelift/object/LICENSE

@@ -0,0 +1,220 @@
+
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+

cranelift/object/README.md

@@ -0,0 +1,4 @@
+This crate contains a library that enables
+[Cranelift](https://crates.io/crates/cranelift)
+to emit native object (".o") files, using the
+[object](https://crates.io/crates/object) library.

cranelift/object/src/backend.rs

@@ -0,0 +1,584 @@
+//! Defines `ObjectBackend`.
+
+use crate::traps::{ObjectTrapSink, ObjectTrapSite};
+use cranelift_codegen::binemit::{
+    Addend, CodeOffset, NullStackmapSink, NullTrapSink, Reloc, RelocSink,
+};
+use cranelift_codegen::entity::SecondaryMap;
+use cranelift_codegen::isa::TargetIsa;
+use cranelift_codegen::{self, binemit, ir};
+use cranelift_module::{
+    Backend, DataContext, DataDescription, DataId, FuncId, Init, Linkage, ModuleNamespace,
+    ModuleResult,
+};
+use object::write::{Object, Relocation, SectionId, StandardSection, Symbol, SymbolId};
+use object::{RelocationEncoding, RelocationKind, SymbolKind, SymbolScope};
+use std::collections::HashMap;
+use target_lexicon::PointerWidth;
+
+#[derive(Debug)]
+/// Setting to enable collection of traps. Setting this to `Enabled` in
+/// `ObjectBuilder` means that `ObjectProduct` will contains trap sites.
+pub enum ObjectTrapCollection {
+    /// `ObjectProduct::traps` will be empty
+    Disabled,
+    /// `ObjectProduct::traps` will contain trap sites
+    Enabled,
+}
+
+/// A builder for `ObjectBackend`.
+pub struct ObjectBuilder {
+    isa: Box<dyn TargetIsa>,
+    name: String,
+    collect_traps: ObjectTrapCollection,
+    libcall_names: Box<dyn Fn(ir::LibCall) -> String>,
+    function_alignment: u64,
+}
+
+impl ObjectBuilder {
+    /// Create a new `ObjectBuilder` using the given Cranelift target, that
+    /// can be passed to
+    /// [`Module::new`](cranelift_module/struct.Module.html#method.new].
+    ///
+    /// `collect_traps` setting determines whether trap information is collected in the
+    /// `ObjectProduct`.
+    ///
+    /// The `libcall_names` function provides a way to translate `cranelift_codegen`'s `ir::LibCall`
+    /// enum to symbols. LibCalls are inserted in the IR as part of the legalization for certain
+    /// floating point instructions, and for stack probes. If you don't know what to use for this
+    /// argument, use `cranelift_module::default_libcall_names()`.
+    pub fn new(
+        isa: Box<dyn TargetIsa>,
+        name: String,
+        collect_traps: ObjectTrapCollection,
+        libcall_names: Box<dyn Fn(ir::LibCall) -> String>,
+    ) -> ModuleResult<Self> {
+        Ok(Self {
+            isa,
+            name,
+            collect_traps,
+            libcall_names,
+            function_alignment: 1,
+        })
+    }
+
+    /// Set the alignment used for functions.
+    pub fn function_alignment(&mut self, alignment: u64) -> &mut Self {
+        self.function_alignment = alignment;
+        self
+    }
+}
+
+/// A `ObjectBackend` implements `Backend` and emits ".o" files using the `object` library.
+///
+/// See the `ObjectBuilder` for a convenient way to construct `ObjectBackend` instances.
+pub struct ObjectBackend {
+    isa: Box<dyn TargetIsa>,
+    object: Object,
+    functions: SecondaryMap<FuncId, Option<SymbolId>>,
+    data_objects: SecondaryMap<DataId, Option<SymbolId>>,
+    traps: SecondaryMap<FuncId, Vec<ObjectTrapSite>>,
+    libcalls: HashMap<ir::LibCall, SymbolId>,
+    libcall_names: Box<dyn Fn(ir::LibCall) -> String>,
+    collect_traps: ObjectTrapCollection,
+    function_alignment: u64,
+}
+
+impl Backend for ObjectBackend {
+    type Builder = ObjectBuilder;
+
+    type CompiledFunction = ObjectCompiledFunction;
+    type CompiledData = ObjectCompiledData;
+
+    // There's no need to return individual artifacts; we're writing them into
+    // the output file instead.
+    type FinalizedFunction = ();
+    type FinalizedData = ();
+
+    type Product = ObjectProduct;
+
+    /// Create a new `ObjectBackend` using the given Cranelift target.
+    fn new(builder: ObjectBuilder) -> Self {
+        let triple = builder.isa.triple();
+        let mut object = Object::new(triple.binary_format, triple.architecture);
+        object.add_file_symbol(builder.name.as_bytes().to_vec());
+        Self {
+            isa: builder.isa,
+            object,
+            functions: SecondaryMap::new(),
+            data_objects: SecondaryMap::new(),
+            traps: SecondaryMap::new(),
+            libcalls: HashMap::new(),
+            libcall_names: builder.libcall_names,
+            collect_traps: builder.collect_traps,
+            function_alignment: builder.function_alignment,
+        }
+    }
+
+    fn isa(&self) -> &dyn TargetIsa {
+        &*self.isa
+    }
+
+    fn declare_function(&mut self, id: FuncId, name: &str, linkage: Linkage) {
+        let (scope, weak) = translate_linkage(linkage);
+
+        if let Some(function) = self.functions[id] {
+            let symbol = self.object.symbol_mut(function);
+            symbol.scope = scope;
+            symbol.weak = weak;
+        } else {
+            let symbol_id = self.object.add_symbol(Symbol {
+                name: name.as_bytes().to_vec(),
+                value: 0,
+                size: 0,
+                kind: SymbolKind::Text,
+                scope,
+                weak,
+                section: None,
+            });
+            self.functions[id] = Some(symbol_id);
+        }
+    }
+
+    fn declare_data(
+        &mut self,
+        id: DataId,
+        name: &str,
+        linkage: Linkage,
+        _writable: bool,
+        _align: Option<u8>,
+    ) {
+        let (scope, weak) = translate_linkage(linkage);
+
+        if let Some(data) = self.data_objects[id] {
+            let symbol = self.object.symbol_mut(data);
+            symbol.scope = scope;
+            symbol.weak = weak;
+        } else {
+            let symbol_id = self.object.add_symbol(Symbol {
+                name: name.as_bytes().to_vec(),
+                value: 0,
+                size: 0,
+                kind: SymbolKind::Data,
+                scope,
+                weak,
+                section: None,
+            });
+            self.data_objects[id] = Some(symbol_id);
+        }
+    }
+
+    fn define_function(
+        &mut self,
+        func_id: FuncId,
+        _name: &str,
+        ctx: &cranelift_codegen::Context,
+        _namespace: &ModuleNamespace<Self>,
+        code_size: u32,
+    ) -> ModuleResult<ObjectCompiledFunction> {
+        let mut code: Vec<u8> = vec![0; code_size as usize];
+        let mut reloc_sink = ObjectRelocSink::default();
+        let mut trap_sink = ObjectTrapSink::default();
+        let mut stackmap_sink = NullStackmapSink {};
+
+        if let ObjectTrapCollection::Enabled = self.collect_traps {
+            unsafe {
+                ctx.emit_to_memory(
+                    &*self.isa,
+                    code.as_mut_ptr(),
+                    &mut reloc_sink,
+                    &mut trap_sink,
+                    &mut stackmap_sink,
+                )
+            };
+        } else {
+            let mut trap_sink = NullTrapSink {};
+            unsafe {
+                ctx.emit_to_memory(
+                    &*self.isa,
+                    code.as_mut_ptr(),
+                    &mut reloc_sink,
+                    &mut trap_sink,
+                    &mut stackmap_sink,
+                )
+            };
+        }
+
+        let symbol = self.functions[func_id].unwrap();
+        let section = self.object.section_id(StandardSection::Text);
+        let offset = self
+            .object
+            .add_symbol_data(symbol, section, &code, self.function_alignment);
+        self.traps[func_id] = trap_sink.sites;
+        Ok(ObjectCompiledFunction {
+            offset,
+            size: code_size,
+            section,
+            relocs: reloc_sink.relocs,
+        })
+    }
+
+    fn define_data(
+        &mut self,
+        data_id: DataId,
+        _name: &str,
+        writable: bool,
+        align: Option<u8>,
+        data_ctx: &DataContext,
+        _namespace: &ModuleNamespace<Self>,
+    ) -> ModuleResult<ObjectCompiledData> {
+        let &DataDescription {
+            ref init,
+            ref function_decls,
+            ref data_decls,
+            ref function_relocs,
+            ref data_relocs,
+        } = data_ctx.description();
+
+        let size = init.size();
+        let mut data = Vec::with_capacity(size);
+        match *init {
+            Init::Uninitialized => {
+                panic!("data is not initialized yet");
+            }
+            Init::Zeros { .. } => {
+                data.resize(size, 0);
+            }
+            Init::Bytes { ref contents } => {
+                data.extend_from_slice(contents);
+            }
+        }
+
+        let reloc_size = match self.isa.triple().pointer_width().unwrap() {
+            PointerWidth::U16 => 16,
+            PointerWidth::U32 => 32,
+            PointerWidth::U64 => 64,
+        };
+        let mut relocs = Vec::new();
+        for &(offset, id) in function_relocs {
+            relocs.push(RelocRecord {
+                offset,
+                name: function_decls[id].clone(),
+                kind: RelocationKind::Absolute,
+                encoding: RelocationEncoding::Generic,
+                size: reloc_size,
+                addend: 0,
+            });
+        }
+        for &(offset, id, addend) in data_relocs {
+            relocs.push(RelocRecord {
+                offset,
+                name: data_decls[id].clone(),
+                kind: RelocationKind::Absolute,
+                encoding: RelocationEncoding::Generic,
+                size: reloc_size,
+                addend,
+            });
+        }
+
+        let symbol = self.data_objects[data_id].unwrap();
+        let section = self.object.section_id(if writable {
+            StandardSection::Data
+        } else if relocs.is_empty() {
+            StandardSection::ReadOnlyData
+        } else {
+            StandardSection::ReadOnlyDataWithRel
+        });
+        let offset =
+            self.object
+                .add_symbol_data(symbol, section, &data, u64::from(align.unwrap_or(1)));
+        Ok(ObjectCompiledData {
+            offset,
+            section,
+            relocs,
+        })
+    }
+
+    fn write_data_funcaddr(
+        &mut self,
+        _data: &mut ObjectCompiledData,
+        _offset: usize,
+        _what: ir::FuncRef,
+    ) {
+        unimplemented!()
+    }
+
+    fn write_data_dataaddr(
+        &mut self,
+        _data: &mut ObjectCompiledData,
+        _offset: usize,
+        _what: ir::GlobalValue,
+        _usize: binemit::Addend,
+    ) {
+        unimplemented!()
+    }
+
+    fn finalize_function(
+        &mut self,
+        _id: FuncId,
+        func: &ObjectCompiledFunction,
+        namespace: &ModuleNamespace<Self>,
+    ) {
+        for &RelocRecord {
+            offset,
+            ref name,
+            kind,
+            encoding,
+            size,
+            addend,
+        } in &func.relocs
+        {
+            let offset = func.offset + offset as u64;
+            let symbol = self.get_symbol(namespace, name);
+            self.object
+                .add_relocation(
+                    func.section,
+                    Relocation {
+                        offset,
+                        size,
+                        kind,
+                        encoding,
+                        symbol,
+                        addend,
+                    },
+                )
+                .unwrap();
+        }
+    }
+
+    fn get_finalized_function(&self, _func: &ObjectCompiledFunction) {
+        // Nothing to do.
+    }
+
+    fn finalize_data(
+        &mut self,
+        _id: DataId,
+        data: &ObjectCompiledData,
+        namespace: &ModuleNamespace<Self>,
+    ) {
+        for &RelocRecord {
+            offset,
+            ref name,
+            kind,
+            encoding,
+            size,
+            addend,
+        } in &data.relocs
+        {
+            let offset = data.offset + offset as u64;
+            let symbol = self.get_symbol(namespace, name);
+            self.object
+                .add_relocation(
+                    data.section,
+                    Relocation {
+                        offset,
+                        size,
+                        kind,
+                        encoding,
+                        symbol,
+                        addend,
+                    },
+                )
+                .unwrap();
+        }
+    }
+
+    fn get_finalized_data(&self, _data: &ObjectCompiledData) {
+        // Nothing to do.
+    }
+
+    fn publish(&mut self) {
+        // Nothing to do.
+    }
+
+    fn finish(self) -> ObjectProduct {
+        ObjectProduct {
+            object: self.object,
+            functions: self.functions,
+            data_objects: self.data_objects,
+            traps: self.traps,
+        }
+    }
+}
+
+impl ObjectBackend {
+    // This should only be called during finalization because it creates
+    // symbols for missing libcalls.
+    fn get_symbol(
+        &mut self,
+        namespace: &ModuleNamespace<Self>,
+        name: &ir::ExternalName,
+    ) -> SymbolId {
+        match *name {
+            ir::ExternalName::User { .. } => {
+                if namespace.is_function(name) {
+                    let id = namespace.get_function_id(name);
+                    self.functions[id].unwrap()
+                } else {
+                    let id = namespace.get_data_id(name);
+                    self.data_objects[id].unwrap()
+                }
+            }
+            ir::ExternalName::LibCall(ref libcall) => {
+                let name = (self.libcall_names)(*libcall);
+                if let Some(symbol) = self.object.symbol_id(name.as_bytes()) {
+                    symbol
+                } else if let Some(symbol) = self.libcalls.get(libcall) {
+                    *symbol
+                } else {
+                    let symbol = self.object.add_symbol(Symbol {
+                        name: name.as_bytes().to_vec(),
+                        value: 0,
+                        size: 0,
+                        kind: SymbolKind::Text,
+                        scope: SymbolScope::Unknown,
+                        weak: false,
+                        section: None,
+                    });
+                    self.libcalls.insert(*libcall, symbol);
+                    symbol
+                }
+            }
+            _ => panic!("invalid ExternalName {}", name),
+        }
+    }
+}
+
+fn translate_linkage(linkage: Linkage) -> (SymbolScope, bool) {
+    let scope = match linkage {
+        Linkage::Import => SymbolScope::Unknown,
+        Linkage::Local => SymbolScope::Compilation,
+        Linkage::Export | Linkage::Preemptible => SymbolScope::Dynamic,
+    };
+    // TODO: this matches rustc_codegen_cranelift, but may be wrong.
+    let weak = linkage == Linkage::Preemptible;
+    (scope, weak)
+}
+
+#[derive(Clone)]
+pub struct ObjectCompiledFunction {
+    offset: u64,
+    size: u32,
+    section: SectionId,
+    relocs: Vec<RelocRecord>,
+}
+
+#[derive(Clone)]
+pub struct ObjectCompiledData {
+    offset: u64,
+    section: SectionId,
+    relocs: Vec<RelocRecord>,
+}
+
+/// This is the output of `Module`'s
+/// [`finish`](../cranelift_module/struct.Module.html#method.finish) function.
+/// It contains the generated `Object` and other information produced during
+/// compilation.
+pub struct ObjectProduct {
+    /// Object artifact with all functions and data from the module defined.
+    pub object: Object,
+    /// Symbol IDs for functions (both declared and defined).
+    pub functions: SecondaryMap<FuncId, Option<SymbolId>>,
+    /// Symbol IDs for data objects (both declared and defined).
+    pub data_objects: SecondaryMap<DataId, Option<SymbolId>>,
+    /// Trap sites for defined functions.
+    pub traps: SecondaryMap<FuncId, Vec<ObjectTrapSite>>,
+}
+
+impl ObjectProduct {
+    /// Return the `SymbolId` for the given function.
+    #[inline]
+    pub fn function_symbol(&self, id: FuncId) -> SymbolId {
+        self.functions[id].unwrap()
+    }
+
+    /// Return the `SymbolId` for the given data object.
+    #[inline]
+    pub fn data_symbol(&self, id: DataId) -> SymbolId {
+        self.data_objects[id].unwrap()
+    }
+
+    /// Write the object bytes in memory.
+    #[inline]
+    pub fn emit(self) -> Result<Vec<u8>, String> {
+        self.object.write()
+    }
+}
+
+#[derive(Clone)]
+struct RelocRecord {
+    offset: CodeOffset,
+    name: ir::ExternalName,
+    kind: RelocationKind,
+    encoding: RelocationEncoding,
+    size: u8,
+    addend: Addend,
+}
+
+#[derive(Default)]
+struct ObjectRelocSink {
+    relocs: Vec<RelocRecord>,
+}
+
+impl RelocSink for ObjectRelocSink {
+    fn reloc_ebb(&mut self, _offset: CodeOffset, _reloc: Reloc, _ebb_offset: CodeOffset) {
+        unimplemented!();
+    }
+
+    fn reloc_external(
+        &mut self,
+        offset: CodeOffset,
+        reloc: Reloc,
+        name: &ir::ExternalName,
+        addend: Addend,
+    ) {
+        let (kind, encoding, size) = match reloc {
+            Reloc::Abs4 => (RelocationKind::Absolute, RelocationEncoding::Generic, 32),
+            Reloc::Abs8 => (RelocationKind::Absolute, RelocationEncoding::Generic, 64),
+            Reloc::X86PCRel4 => (RelocationKind::Relative, RelocationEncoding::Generic, 32),
+            Reloc::X86CallPCRel4 => (RelocationKind::Relative, RelocationEncoding::X86Branch, 32),
+            // TODO: Get Cranelift to tell us when we can use
+            // R_X86_64_GOTPCRELX/R_X86_64_REX_GOTPCRELX.
+            Reloc::X86CallPLTRel4 => (
+                RelocationKind::PltRelative,
+                RelocationEncoding::X86Branch,
+                32,
+            ),
+            Reloc::X86GOTPCRel4 => (RelocationKind::GotRelative, RelocationEncoding::Generic, 32),
+            // FIXME
+            _ => unimplemented!(),
+        };
+        self.relocs.push(RelocRecord {
+            offset,
+            name: name.clone(),
+            kind,
+            encoding,
+            size,
+            addend,
+        });
+    }
+
+    fn reloc_jt(&mut self, _offset: CodeOffset, reloc: Reloc, _jt: ir::JumpTable) {
+        match reloc {
+            Reloc::X86PCRelRodata4 => {
+                // Not necessary to record this unless we are going to split apart code and its
+                // jumptbl/rodata.
+            }
+            _ => {
+                panic!("Unhandled reloc");
+            }
+        }
+    }
+
+    fn reloc_constant(&mut self, _offset: CodeOffset, reloc: Reloc, _jt: ir::ConstantOffset) {
+        match reloc {
+            Reloc::X86PCRelRodata4 => {
+                // Not necessary to record this unless we are going to split apart code and its
+                // jumptbl/rodata.
+            }
+            _ => {
+                panic!("Unhandled reloc");
+            }
+        }
+    }
+}

cranelift/object/src/lib.rs

@@ -0,0 +1,38 @@
+//! Top-level lib.rs for `cranelift_object`.
+//!
+//! Users of this module should not have to depend on `object` directly.
+
+#![deny(
+    missing_docs,
+    trivial_numeric_casts,
+    unused_extern_crates,
+    unstable_features
+)]
+#![warn(unused_import_braces)]
+#![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
+#![cfg_attr(
+    feature = "cargo-clippy",
+    allow(clippy::new_without_default, clippy::new_without_default_derive)
+)]
+#![cfg_attr(
+    feature = "cargo-clippy",
+    warn(
+        clippy::float_arithmetic,
+        clippy::mut_mut,
+        clippy::nonminimal_bool,
+        clippy::option_map_unwrap_or,
+        clippy::option_map_unwrap_or_else,
+        clippy::print_stdout,
+        clippy::unicode_not_nfc,
+        clippy::use_self
+    )
+)]
+
+mod backend;
+mod traps;
+
+pub use crate::backend::{ObjectBackend, ObjectBuilder, ObjectProduct, ObjectTrapCollection};
+pub use crate::traps::{ObjectTrapSink, ObjectTrapSite};
+
+/// Version number of this crate.
+pub const VERSION: &str = env!("CARGO_PKG_VERSION");

cranelift/object/src/traps.rs

@@ -0,0 +1,32 @@
+//! Records every `TrapCode` that cranelift outputs during code generation,
+//! for every function in the module. This data may be useful at runtime.
+
+use cranelift_codegen::{binemit, ir};
+
+/// Record of the arguments cranelift passes to `TrapSink::trap`
+#[derive(Clone)]
+pub struct ObjectTrapSite {
+    /// Offset into function
+    pub offset: binemit::CodeOffset,
+    /// Source location given to cranelift
+    pub srcloc: ir::SourceLoc,
+    /// Trap code, as determined by cranelift
+    pub code: ir::TrapCode,
+}
+
+/// Record of the trap sites for a given function
+#[derive(Default, Clone)]
+pub struct ObjectTrapSink {
+    /// All trap sites collected in function
+    pub sites: Vec<ObjectTrapSite>,
+}
+
+impl binemit::TrapSink for ObjectTrapSink {
+    fn trap(&mut self, offset: binemit::CodeOffset, srcloc: ir::SourceLoc, code: ir::TrapCode) {
+        self.sites.push(ObjectTrapSite {
+            offset,
+            srcloc,
+            code,
+        });
+    }
+}

cranelift/simplejit/src/backend.rs

@@ -7,7 +7,8 @@ use cranelift_codegen::binemit::{
 use cranelift_codegen::isa::TargetIsa;
 use cranelift_codegen::{self, ir, settings};
 use cranelift_module::{
-    Backend, DataContext, DataDescription, Init, Linkage, ModuleNamespace, ModuleResult,
+    Backend, DataContext, DataDescription, DataId, FuncId, Init, Linkage, ModuleNamespace,
+    ModuleResult,
 };
 use cranelift_native;
 #[cfg(not(windows))]
@@ -222,12 +223,13 @@ impl<'simple_jit_backend> Backend for SimpleJITBackend {
         &*self.isa
     }
 
-    fn declare_function(&mut self, _name: &str, _linkage: Linkage) {
+    fn declare_function(&mut self, _id: FuncId, _name: &str, _linkage: Linkage) {
         // Nothing to do.
     }
 
     fn declare_data(
         &mut self,
+        _id: DataId,
         _name: &str,
         _linkage: Linkage,
         _writable: bool,
@@ -238,6 +240,7 @@ impl<'simple_jit_backend> Backend for SimpleJITBackend {
 
     fn define_function(
         &mut self,
+        _id: FuncId,
         name: &str,
         ctx: &cranelift_codegen::Context,
         _namespace: &ModuleNamespace<Self>,
@@ -283,6 +286,7 @@ impl<'simple_jit_backend> Backend for SimpleJITBackend {
 
     fn define_data(
         &mut self,
+        _id: DataId,
         _name: &str,
         writable: bool,
         align: Option<u8>,
@@ -372,6 +376,7 @@ impl<'simple_jit_backend> Backend for SimpleJITBackend {
 
     fn finalize_function(
         &mut self,
+        _id: FuncId,
         func: &Self::CompiledFunction,
         namespace: &ModuleNamespace<Self>,
     ) -> Self::FinalizedFunction {
@@ -425,6 +430,7 @@ impl<'simple_jit_backend> Backend for SimpleJITBackend {
 
     fn finalize_data(
         &mut self,
+        _id: DataId,
         data: &Self::CompiledData,
         namespace: &ModuleNamespace<Self>,
     ) -> Self::FinalizedData {