]> git.lizzy.rs Git - rust.git/blobdiff - src/constant.rs
Rollup merge of #81618 - bjorn3:sync_cg_clif-2021-02-01, r=bjorn3
[rust.git] / src / constant.rs
index 1d98404c75fbd1069736316abf1696171723b81d..5702832bcb67d99ac60baa6cb5bbd75bcedc5908 100644 (file)
@@ -1,19 +1,16 @@
-use std::borrow::Cow;
+//! Handling of `static`s, `const`s and promoted allocations
 
 use rustc_span::DUMMY_SP;
 
+use rustc_data_structures::fx::FxHashSet;
+use rustc_errors::ErrorReported;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::interpret::{
-    read_target_uint, AllocId, Allocation, ConstValue, GlobalAlloc, InterpResult, Scalar,
-};
-use rustc_middle::ty::{layout::Align, Const, ConstKind};
-use rustc_data_structures::fx::FxHashSet;
-use rustc_mir::interpret::{
-    ImmTy, InterpCx, Machine, Memory, MemoryKind, OpTy, PlaceTy, Pointer,
-    StackPopCleanup, StackPopJump,
+    read_target_uint, AllocId, Allocation, ConstValue, ErrorHandled, GlobalAlloc, Pointer, Scalar,
 };
+use rustc_middle::ty::{Const, ConstKind};
 
-use cranelift_codegen::ir::GlobalValue;
+use cranelift_codegen::ir::GlobalValueData;
 use cranelift_module::*;
 
 use crate::prelude::*;
@@ -31,7 +28,7 @@ enum TodoItem {
 }
 
 impl ConstantCx {
-    pub(crate) fn finalize(mut self, tcx: TyCtxt<'_>, module: &mut Module<impl Backend>) {
+    pub(crate) fn finalize(mut self, tcx: TyCtxt<'_>, module: &mut impl Module) {
         //println!("todo {:?}", self.todo);
         define_all_allocs(tcx, module, &mut self);
         //println!("done {:?}", self.done);
@@ -39,200 +36,273 @@ pub(crate) fn finalize(mut self, tcx: TyCtxt<'_>, module: &mut Module<impl Backe
     }
 }
 
+pub(crate) fn check_constants(fx: &mut FunctionCx<'_, '_, impl Module>) {
+    for constant in &fx.mir.required_consts {
+        let const_ = fx.monomorphize(constant.literal);
+        match const_.val {
+            ConstKind::Value(_) => {}
+            ConstKind::Unevaluated(def, ref substs, promoted) => {
+                if let Err(err) =
+                    fx.tcx
+                        .const_eval_resolve(ParamEnv::reveal_all(), def, substs, promoted, None)
+                {
+                    match err {
+                        ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted => {
+                            fx.tcx
+                                .sess
+                                .span_err(constant.span, "erroneous constant encountered");
+                        }
+                        ErrorHandled::TooGeneric => {
+                            span_bug!(
+                                constant.span,
+                                "codgen encountered polymorphic constant: {:?}",
+                                err
+                            );
+                        }
+                    }
+                }
+            }
+            ConstKind::Param(_)
+            | ConstKind::Infer(_)
+            | ConstKind::Bound(_, _)
+            | ConstKind::Placeholder(_)
+            | ConstKind::Error(_) => unreachable!("{:?}", const_),
+        }
+    }
+}
+
 pub(crate) fn codegen_static(constants_cx: &mut ConstantCx, def_id: DefId) {
     constants_cx.todo.push(TodoItem::Static(def_id));
 }
 
+pub(crate) fn codegen_tls_ref<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Module>,
+    def_id: DefId,
+    layout: TyAndLayout<'tcx>,
+) -> CValue<'tcx> {
+    let data_id = data_id_for_static(fx.tcx, &mut fx.cx.module, def_id, false);
+    let local_data_id = fx.cx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+    #[cfg(debug_assertions)]
+    fx.add_comment(local_data_id, format!("tls {:?}", def_id));
+    let tls_ptr = fx.bcx.ins().tls_value(fx.pointer_type, local_data_id);
+    CValue::by_val(tls_ptr, layout)
+}
+
 fn codegen_static_ref<'tcx>(
-    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+    fx: &mut FunctionCx<'_, 'tcx, impl Module>,
     def_id: DefId,
     layout: TyAndLayout<'tcx>,
 ) -> CPlace<'tcx> {
-    let linkage = crate::linkage::get_static_ref_linkage(fx.tcx, def_id);
-    let data_id = data_id_for_static(fx.tcx, fx.module, def_id, linkage);
-    let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+    let data_id = data_id_for_static(fx.tcx, &mut fx.cx.module, def_id, false);
+    let local_data_id = fx.cx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
     #[cfg(debug_assertions)]
     fx.add_comment(local_data_id, format!("{:?}", def_id));
-    cplace_for_dataid(fx, layout, local_data_id)
+    let global_ptr = fx.bcx.ins().global_value(fx.pointer_type, local_data_id);
+    assert!(!layout.is_unsized(), "unsized statics aren't supported");
+    assert!(
+        matches!(
+            fx.bcx.func.global_values[local_data_id],
+            GlobalValueData::Symbol { tls: false, .. }
+        ),
+        "tls static referenced without Rvalue::ThreadLocalRef"
+    );
+    CPlace::for_ptr(crate::pointer::Pointer::new(global_ptr), layout)
 }
 
-pub(crate) fn trans_constant<'tcx>(
-    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+pub(crate) fn codegen_constant<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Module>,
     constant: &Constant<'tcx>,
 ) -> CValue<'tcx> {
-    let const_ = match constant.literal.val {
-        ConstKind::Unevaluated(def_id, ref substs, promoted) if fx.tcx.is_static(def_id) => {
+    let const_ = fx.monomorphize(constant.literal);
+    let const_val = match const_.val {
+        ConstKind::Value(const_val) => const_val,
+        ConstKind::Unevaluated(def, ref substs, promoted) if fx.tcx.is_static(def.did) => {
             assert!(substs.is_empty());
             assert!(promoted.is_none());
 
             return codegen_static_ref(
                 fx,
-                def_id,
+                def.did,
                 fx.layout_of(fx.monomorphize(&constant.literal.ty)),
-            ).to_cvalue(fx);
+            )
+            .to_cvalue(fx);
+        }
+        ConstKind::Unevaluated(def, ref substs, promoted) => {
+            match fx
+                .tcx
+                .const_eval_resolve(ParamEnv::reveal_all(), def, substs, promoted, None)
+            {
+                Ok(const_val) => const_val,
+                Err(_) => {
+                    fx.tcx
+                        .sess
+                        .span_err(constant.span, "erroneous constant encountered");
+                    return crate::trap::trap_unreachable_ret_value(
+                        fx,
+                        fx.layout_of(const_.ty),
+                        "erroneous constant encountered",
+                    );
+                }
+            }
         }
-        _ => fx.monomorphize(&constant.literal).eval(fx.tcx, ParamEnv::reveal_all()),
+        ConstKind::Param(_)
+        | ConstKind::Infer(_)
+        | ConstKind::Bound(_, _)
+        | ConstKind::Placeholder(_)
+        | ConstKind::Error(_) => unreachable!("{:?}", const_),
     };
 
-    trans_const_value(fx, const_)
+    codegen_const_value(fx, const_val, const_.ty)
 }
 
-pub(crate) fn trans_const_value<'tcx>(
-    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
-    const_: &'tcx Const<'tcx>,
+pub(crate) fn codegen_const_value<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Module>,
+    const_val: ConstValue<'tcx>,
+    ty: Ty<'tcx>,
 ) -> CValue<'tcx> {
-    let ty = fx.monomorphize(&const_.ty);
     let layout = fx.layout_of(ty);
+    assert!(!layout.is_unsized(), "sized const value");
 
     if layout.is_zst() {
-        return CValue::by_ref(
-            crate::Pointer::const_addr(fx, i64::try_from(layout.align.pref.bytes()).unwrap()),
-            layout,
-        );
+        return CValue::by_ref(crate::Pointer::dangling(layout.align.pref), layout);
     }
-    let const_val = match const_.val {
-        ConstKind::Value(const_val) => const_val,
-        _ => unreachable!("Const {:?} should have been evaluated", const_),
-    };
 
     match const_val {
         ConstValue::Scalar(x) => {
             if fx.clif_type(layout.ty).is_none() {
-                return trans_const_place(fx, const_).to_cvalue(fx);
+                let (size, align) = (layout.size, layout.align.pref);
+                let mut alloc = Allocation::from_bytes(
+                    std::iter::repeat(0)
+                        .take(size.bytes_usize())
+                        .collect::<Vec<u8>>(),
+                    align,
+                );
+                let ptr = Pointer::new(AllocId(!0), Size::ZERO); // The alloc id is never used
+                alloc.write_scalar(fx, ptr, x.into(), size).unwrap();
+                let alloc = fx.tcx.intern_const_alloc(alloc);
+                return CValue::by_ref(pointer_for_allocation(fx, alloc), layout);
             }
 
             match x {
-                Scalar::Raw { data, size } => {
-                    assert_eq!(u64::from(size), layout.size.bytes());
-                    return CValue::const_val(fx, layout, data);
-                }
+                Scalar::Int(int) => CValue::const_val(fx, layout, int),
                 Scalar::Ptr(ptr) => {
-                    let alloc_kind = fx.tcx.alloc_map.lock().get(ptr.alloc_id);
+                    let alloc_kind = fx.tcx.get_global_alloc(ptr.alloc_id);
                     let base_addr = match alloc_kind {
                         Some(GlobalAlloc::Memory(alloc)) => {
-                            fx.constants_cx.todo.push(TodoItem::Alloc(ptr.alloc_id));
-                            let data_id = data_id_for_alloc_id(fx.module, ptr.alloc_id, alloc.align);
-                            let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+                            fx.cx.constants_cx.todo.push(TodoItem::Alloc(ptr.alloc_id));
+                            let data_id = data_id_for_alloc_id(
+                                &mut fx.cx.module,
+                                ptr.alloc_id,
+                                alloc.mutability,
+                            );
+                            let local_data_id =
+                                fx.cx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
                             #[cfg(debug_assertions)]
                             fx.add_comment(local_data_id, format!("{:?}", ptr.alloc_id));
                             fx.bcx.ins().global_value(fx.pointer_type, local_data_id)
                         }
                         Some(GlobalAlloc::Function(instance)) => {
-                            let func_id = crate::abi::import_function(fx.tcx, fx.module, instance);
-                            let local_func_id = fx.module.declare_func_in_func(func_id, &mut fx.bcx.func);
+                            let func_id =
+                                crate::abi::import_function(fx.tcx, &mut fx.cx.module, instance);
+                            let local_func_id =
+                                fx.cx.module.declare_func_in_func(func_id, &mut fx.bcx.func);
                             fx.bcx.ins().func_addr(fx.pointer_type, local_func_id)
                         }
                         Some(GlobalAlloc::Static(def_id)) => {
                             assert!(fx.tcx.is_static(def_id));
-                            let linkage = crate::linkage::get_static_ref_linkage(fx.tcx, def_id);
-                            let data_id = data_id_for_static(fx.tcx, fx.module, def_id, linkage);
-                            let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+                            let data_id =
+                                data_id_for_static(fx.tcx, &mut fx.cx.module, def_id, false);
+                            let local_data_id =
+                                fx.cx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
                             #[cfg(debug_assertions)]
                             fx.add_comment(local_data_id, format!("{:?}", def_id));
                             fx.bcx.ins().global_value(fx.pointer_type, local_data_id)
                         }
                         None => bug!("missing allocation {:?}", ptr.alloc_id),
                     };
-                    let val = fx.bcx.ins().iadd_imm(base_addr, i64::try_from(ptr.offset.bytes()).unwrap());
-                    return CValue::by_val(val, layout);
+                    let val = if ptr.offset.bytes() != 0 {
+                        fx.bcx
+                            .ins()
+                            .iadd_imm(base_addr, i64::try_from(ptr.offset.bytes()).unwrap())
+                    } else {
+                        base_addr
+                    };
+                    CValue::by_val(val, layout)
                 }
             }
         }
-        ConstValue::ByRef { alloc, offset } => {
-            let alloc_id = fx.tcx.alloc_map.lock().create_memory_alloc(alloc);
-            fx.constants_cx.todo.push(TodoItem::Alloc(alloc_id));
-            let data_id = data_id_for_alloc_id(fx.module, alloc_id, alloc.align);
-            let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
-            let global_ptr = fx.bcx.ins().global_value(fx.pointer_type, local_data_id);
-            assert!(!layout.is_unsized(), "unsized ConstValue::ByRef not supported");
-            CValue::by_ref(
-                crate::pointer::Pointer::new(global_ptr)
-                    .offset_i64(fx, i64::try_from(offset.bytes()).unwrap()),
-                layout,
-            )
-        }
-        ConstValue::Slice { data: _, start: _, end: _ } => {
-            trans_const_place(fx, const_).to_cvalue(fx)
+        ConstValue::ByRef { alloc, offset } => CValue::by_ref(
+            pointer_for_allocation(fx, alloc)
+                .offset_i64(fx, i64::try_from(offset.bytes()).unwrap()),
+            layout,
+        ),
+        ConstValue::Slice { data, start, end } => {
+            let ptr = pointer_for_allocation(fx, data)
+                .offset_i64(fx, i64::try_from(start).unwrap())
+                .get_addr(fx);
+            let len = fx.bcx.ins().iconst(
+                fx.pointer_type,
+                i64::try_from(end.checked_sub(start).unwrap()).unwrap(),
+            );
+            CValue::by_val_pair(ptr, len, layout)
         }
     }
 }
 
-fn trans_const_place<'tcx>(
-    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
-    const_: &'tcx Const<'tcx>,
-) -> CPlace<'tcx> {
-    // Adapted from https://github.com/rust-lang/rust/pull/53671/files#diff-e0b58bb6712edaa8595ad7237542c958L551
-    let result = || -> InterpResult<'tcx, &'tcx Allocation> {
-        let mut ecx = InterpCx::new(
-            fx.tcx.at(DUMMY_SP),
-            ty::ParamEnv::reveal_all(),
-            TransPlaceInterpreter,
-            (),
-        );
-        ecx.push_stack_frame(
-            fx.instance,
-            DUMMY_SP,
-            fx.mir,
-            None,
-            StackPopCleanup::None { cleanup: false },
-        )
-        .unwrap();
-        let op = ecx.eval_operand(
-            &Operand::Constant(Box::new(Constant {
-                span: DUMMY_SP,
-                user_ty: None,
-                literal: const_,
-            })),
-            None,
-        )?;
-        let ptr = ecx.allocate(op.layout, MemoryKind::Stack);
-        ecx.copy_op(op, ptr.into())?;
-        let alloc = ecx
-            .memory
-            .get_raw(ptr.to_ref().to_scalar()?.assert_ptr().alloc_id)?;
-        Ok(fx.tcx.intern_const_alloc(alloc.clone()))
-    };
-    let alloc = result().expect("unable to convert ConstKind to Allocation");
+fn pointer_for_allocation<'tcx>(
+    fx: &mut FunctionCx<'_, 'tcx, impl Module>,
+    alloc: &'tcx Allocation,
+) -> crate::pointer::Pointer {
+    let alloc_id = fx.tcx.create_memory_alloc(alloc);
+    fx.cx.constants_cx.todo.push(TodoItem::Alloc(alloc_id));
+    let data_id = data_id_for_alloc_id(&mut fx.cx.module, alloc_id, alloc.mutability);
 
-    //println!("const value: {:?} allocation: {:?}", value, alloc);
-    let alloc_id = fx.tcx.alloc_map.lock().create_memory_alloc(alloc);
-    fx.constants_cx.todo.push(TodoItem::Alloc(alloc_id));
-    let data_id = data_id_for_alloc_id(fx.module, alloc_id, alloc.align);
-    let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+    let local_data_id = fx.cx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
     #[cfg(debug_assertions)]
     fx.add_comment(local_data_id, format!("{:?}", alloc_id));
-    cplace_for_dataid(fx, fx.layout_of(const_.ty), local_data_id)
+    let global_ptr = fx.bcx.ins().global_value(fx.pointer_type, local_data_id);
+    crate::pointer::Pointer::new(global_ptr)
 }
 
-fn data_id_for_alloc_id<B: Backend>(
-    module: &mut Module<B>,
+fn data_id_for_alloc_id(
+    module: &mut impl Module,
     alloc_id: AllocId,
-    align: Align,
+    mutability: rustc_hir::Mutability,
 ) -> DataId {
     module
         .declare_data(
-            &format!("__alloc_{}", alloc_id.0),
+            &format!(".L__alloc_{:x}", alloc_id.0),
             Linkage::Local,
+            mutability == rustc_hir::Mutability::Mut,
             false,
-            false,
-            Some(align.bytes() as u8),
         )
         .unwrap()
 }
 
 fn data_id_for_static(
     tcx: TyCtxt<'_>,
-    module: &mut Module<impl Backend>,
+    module: &mut impl Module,
     def_id: DefId,
-    linkage: Linkage,
+    definition: bool,
 ) -> DataId {
-    let instance = Instance::mono(tcx, def_id);
-    let symbol_name = tcx.symbol_name(instance).name.as_str();
-    let ty = instance.monomorphic_ty(tcx);
+    let rlinkage = tcx.codegen_fn_attrs(def_id).linkage;
+    let linkage = if definition {
+        crate::linkage::get_static_linkage(tcx, def_id)
+    } else if rlinkage == Some(rustc_middle::mir::mono::Linkage::ExternalWeak)
+        || rlinkage == Some(rustc_middle::mir::mono::Linkage::WeakAny)
+    {
+        Linkage::Preemptible
+    } else {
+        Linkage::Import
+    };
+
+    let instance = Instance::mono(tcx, def_id).polymorphize(tcx);
+    let symbol_name = tcx.symbol_name(instance).name;
+    let ty = instance.ty(tcx, ParamEnv::reveal_all());
     let is_mutable = if tcx.is_mutable_static(def_id) {
         true
     } else {
-        !ty.is_freeze(tcx, ParamEnv::reveal_all(), DUMMY_SP)
+        !ty.is_freeze(tcx.at(DUMMY_SP), ParamEnv::reveal_all())
     };
     let align = tcx
         .layout_of(ParamEnv::reveal_all().and(ty))
@@ -249,78 +319,67 @@ fn data_id_for_static(
             linkage,
             is_mutable,
             attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL),
-            Some(align.try_into().unwrap()),
         )
         .unwrap();
 
-    if linkage == Linkage::Preemptible {
-        if let ty::RawPtr(_) = ty.kind {
-        } else {
-            tcx.sess.span_fatal(
-                tcx.def_span(def_id),
-                "must have type `*const T` or `*mut T` due to `#[linkage]` attribute",
-            )
-        }
-
+    if rlinkage.is_some() {
+        // Comment copied from https://github.com/rust-lang/rust/blob/45060c2a66dfd667f88bd8b94261b28a58d85bd5/src/librustc_codegen_llvm/consts.rs#L141
+        // Declare an internal global `extern_with_linkage_foo` which
+        // is initialized with the address of `foo`.  If `foo` is
+        // discarded during linking (for example, if `foo` has weak
+        // linkage and there are no definitions), then
+        // `extern_with_linkage_foo` will instead be initialized to
+        // zero.
+
+        let ref_name = format!("_rust_extern_with_linkage_{}", symbol_name);
+        let ref_data_id = module
+            .declare_data(&ref_name, Linkage::Local, false, false)
+            .unwrap();
         let mut data_ctx = DataContext::new();
-        data_ctx.define_zeroinit(pointer_ty(tcx).bytes() as usize);
-        match module.define_data(data_id, &data_ctx) {
-            // Everytime a weak static is referenced, there will be a zero pointer definition,
+        data_ctx.set_align(align);
+        let data = module.declare_data_in_data(data_id, &mut data_ctx);
+        data_ctx.define(
+            std::iter::repeat(0)
+                .take(pointer_ty(tcx).bytes() as usize)
+                .collect(),
+        );
+        data_ctx.write_data_addr(0, data, 0);
+        match module.define_data(ref_data_id, &data_ctx) {
+            // Every time the static is referenced there will be another definition of this global,
             // so duplicate definitions are expected and allowed.
             Err(ModuleError::DuplicateDefinition(_)) => {}
             res => res.unwrap(),
         }
+        ref_data_id
+    } else {
+        data_id
     }
-
-    data_id
 }
 
-fn cplace_for_dataid<'tcx>(
-    fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
-    layout: TyAndLayout<'tcx>,
-    local_data_id: GlobalValue,
-) -> CPlace<'tcx> {
-    let global_ptr = fx.bcx.ins().global_value(fx.pointer_type, local_data_id);
-    assert!(!layout.is_unsized(), "unsized statics aren't supported");
-    CPlace::for_ptr(crate::pointer::Pointer::new(global_ptr), layout)
-}
-
-fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut Module<impl Backend>, cx: &mut ConstantCx) {
-    let memory = Memory::<TransPlaceInterpreter>::new(tcx.at(DUMMY_SP), ());
-
+fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut impl Module, cx: &mut ConstantCx) {
     while let Some(todo_item) = cx.todo.pop() {
-        let (data_id, alloc) = match todo_item {
+        let (data_id, alloc, section_name) = match todo_item {
             TodoItem::Alloc(alloc_id) => {
                 //println!("alloc_id {}", alloc_id);
-                let alloc = memory.get_raw(alloc_id).unwrap();
-                let data_id = data_id_for_alloc_id(module, alloc_id, alloc.align);
-                (data_id, alloc)
+                let alloc = match tcx.get_global_alloc(alloc_id).unwrap() {
+                    GlobalAlloc::Memory(alloc) => alloc,
+                    GlobalAlloc::Function(_) | GlobalAlloc::Static(_) => unreachable!(),
+                };
+                let data_id = data_id_for_alloc_id(module, alloc_id, alloc.mutability);
+                (data_id, alloc, None)
             }
             TodoItem::Static(def_id) => {
                 //println!("static {:?}", def_id);
 
-                if tcx.is_foreign_item(def_id) {
-                    continue;
-                }
-
-                let const_ = tcx.const_eval_poly(def_id).unwrap();
+                let section_name = tcx
+                    .codegen_fn_attrs(def_id)
+                    .link_section
+                    .map(|s| s.as_str());
 
-                let alloc = match const_ {
-                    ConstValue::ByRef { alloc, offset } if offset.bytes() == 0 => alloc,
-                    _ => bug!("static const eval returned {:#?}", const_),
-                };
+                let alloc = tcx.eval_static_initializer(def_id).unwrap();
 
-                let data_id = data_id_for_static(
-                    tcx,
-                    module,
-                    def_id,
-                    if tcx.is_reachable_non_generic(def_id) {
-                        Linkage::Export
-                    } else {
-                        Linkage::Export // FIXME Set hidden visibility
-                    },
-                );
-                (data_id, alloc)
+                let data_id = data_id_for_static(tcx, module, def_id, true);
+                (data_id, alloc, section_name)
             }
         };
 
@@ -330,8 +389,16 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut Module<impl Backend>, cx: &mu
         }
 
         let mut data_ctx = DataContext::new();
+        data_ctx.set_align(alloc.align.bytes());
+
+        if let Some(section_name) = section_name {
+            // FIXME set correct segment for Mach-O files
+            data_ctx.set_segment_section("", &*section_name);
+        }
 
-        let bytes = alloc.inspect_with_undef_and_ptr_outside_interpreter(0..alloc.len()).to_vec();
+        let bytes = alloc
+            .inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len())
+            .to_vec();
         data_ctx.define(bytes.into_boxed_slice());
 
         for &(offset, (_tag, reloc)) in alloc.relocations().iter() {
@@ -339,15 +406,13 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut Module<impl Backend>, cx: &mu
                 let endianness = tcx.data_layout.endian;
                 let offset = offset.bytes() as usize;
                 let ptr_size = tcx.data_layout.pointer_size;
-                let bytes = &alloc.inspect_with_undef_and_ptr_outside_interpreter(offset..offset + ptr_size.bytes() as usize);
+                let bytes = &alloc.inspect_with_uninit_and_ptr_outside_interpreter(
+                    offset..offset + ptr_size.bytes() as usize,
+                );
                 read_target_uint(endianness, bytes).unwrap()
             };
 
-            // Don't inline `reloc_target_alloc` into the match. That would cause `tcx.alloc_map`
-            // to be locked for the duration of the match. `data_id_for_static` however may try
-            // to lock `tcx.alloc_map` itself while calculating the layout of the target static.
-            // This would cause a panic in single threaded rustc and a deadlock for parallel rustc.
-            let reloc_target_alloc = tcx.alloc_map.lock().get(reloc).unwrap();
+            let reloc_target_alloc = tcx.get_global_alloc(reloc).unwrap();
             let data_id = match reloc_target_alloc {
                 GlobalAlloc::Function(instance) => {
                     assert_eq!(addend, 0);
@@ -356,24 +421,26 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut Module<impl Backend>, cx: &mu
                     data_ctx.write_function_addr(offset.bytes() as u32, local_func_id);
                     continue;
                 }
-                GlobalAlloc::Memory(_) => {
+                GlobalAlloc::Memory(target_alloc) => {
                     cx.todo.push(TodoItem::Alloc(reloc));
-                    data_id_for_alloc_id(module, reloc, alloc.align)
+                    data_id_for_alloc_id(module, reloc, target_alloc.mutability)
                 }
                 GlobalAlloc::Static(def_id) => {
-                    if tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) {
-                        tcx.sess.fatal(&format!("Allocation {:?} contains reference to TLS value {:?}", alloc, def_id));
+                    if tcx
+                        .codegen_fn_attrs(def_id)
+                        .flags
+                        .contains(CodegenFnAttrFlags::THREAD_LOCAL)
+                    {
+                        tcx.sess.fatal(&format!(
+                            "Allocation {:?} contains reference to TLS value {:?}",
+                            alloc, def_id
+                        ));
                     }
 
                     // Don't push a `TodoItem::Static` here, as it will cause statics used by
                     // multiple crates to be duplicated between them. It isn't necessary anyway,
                     // as it will get pushed by `codegen_static` when necessary.
-                    data_id_for_static(
-                        tcx,
-                        module,
-                        def_id,
-                        crate::linkage::get_static_ref_linkage(tcx, def_id),
-                    )
+                    data_id_for_static(tcx, module, def_id, false)
                 }
             };
 
@@ -381,122 +448,23 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut Module<impl Backend>, cx: &mu
             data_ctx.write_data_addr(offset.bytes() as u32, global_value, addend as i64);
         }
 
-        module.define_data(data_id, &data_ctx).unwrap();
+        // FIXME don't duplicate definitions in lazy jit mode
+        let _ = module.define_data(data_id, &data_ctx);
         cx.done.insert(data_id);
     }
 
     assert!(cx.todo.is_empty(), "{:?}", cx.todo);
 }
 
-struct TransPlaceInterpreter;
-
-impl<'mir, 'tcx> Machine<'mir, 'tcx> for TransPlaceInterpreter {
-    type MemoryKind = !;
-    type ExtraFnVal = !;
-    type PointerTag = ();
-    type AllocExtra = ();
-    type MemoryExtra = ();
-    type FrameExtra = ();
-    type MemoryMap = FxHashMap<AllocId, (MemoryKind<!>, Allocation<()>)>;
-
-    const CHECK_ALIGN: bool = true;
-    const GLOBAL_KIND: Option<!> = None;
-
-    fn enforce_validity(_: &InterpCx<'mir, 'tcx, Self>) -> bool {
-        false
-    }
-
-    fn before_terminator(_: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> {
-        panic!();
-    }
-
-    fn find_mir_or_eval_fn(
-        _: &mut InterpCx<'mir, 'tcx, Self>,
-        _: Span,
-        _: Instance<'tcx>,
-        _: &[OpTy<'tcx>],
-        _: Option<(PlaceTy<'tcx>, BasicBlock)>,
-        _: Option<BasicBlock>,
-    ) -> InterpResult<'tcx, Option<&'mir Body<'tcx>>> {
-        panic!();
-    }
-
-    fn call_intrinsic(
-        _: &mut InterpCx<'mir, 'tcx, Self>,
-        _: Span,
-        _: Instance<'tcx>,
-        _: &[OpTy<'tcx>],
-        _: Option<(PlaceTy<'tcx>, BasicBlock)>,
-        _: Option<BasicBlock>,
-    ) -> InterpResult<'tcx> {
-        panic!();
-    }
-
-    fn binary_ptr_op(
-        _: &InterpCx<'mir, 'tcx, Self>,
-        _: mir::BinOp,
-        _: ImmTy<'tcx>,
-        _: ImmTy<'tcx>,
-    ) -> InterpResult<'tcx, (Scalar, bool, Ty<'tcx>)> {
-        panic!();
-    }
-
-    fn ptr_to_int(_: &Memory<'mir, 'tcx, Self>, _: Pointer<()>) -> InterpResult<'tcx, u64> {
-        panic!();
-    }
-
-    fn box_alloc(_: &mut InterpCx<'mir, 'tcx, Self>, _: PlaceTy<'tcx>) -> InterpResult<'tcx> {
-        panic!();
-    }
-
-    fn init_allocation_extra<'b>(
-        _: &(),
-        _: AllocId,
-        alloc: Cow<'b, Allocation>,
-        _: Option<MemoryKind<!>>,
-    ) -> (Cow<'b, Allocation<(), ()>>, ()) {
-        (alloc, ())
-    }
-
-    fn tag_global_base_pointer(_: &(), _: AllocId) -> Self::PointerTag {
-        ()
-    }
-
-    fn call_extra_fn(
-        _: &mut InterpCx<'mir, 'tcx, Self>,
-        _: !,
-        _: &[OpTy<'tcx, ()>],
-        _: Option<(PlaceTy<'tcx, ()>, BasicBlock)>,
-        _: Option<BasicBlock>,
-    ) -> InterpResult<'tcx> {
-        unreachable!();
-    }
-
-    fn stack_push(_: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> {
-        Ok(())
-    }
-
-    fn stack_pop(_: &mut InterpCx<'mir, 'tcx, Self>, _: (), _: bool) -> InterpResult<'tcx, StackPopJump> {
-        Ok(StackPopJump::Normal)
-    }
-
-    fn assert_panic(
-        _: &mut InterpCx<'mir, 'tcx, Self>,
-        _: &mir::AssertKind<Operand<'tcx>>,
-        _: Option<BasicBlock>,
-    ) -> InterpResult<'tcx> {
-        unreachable!()
-    }
-}
-
 pub(crate) fn mir_operand_get_const_val<'tcx>(
-    fx: &FunctionCx<'_, 'tcx, impl Backend>,
+    fx: &FunctionCx<'_, 'tcx, impl Module>,
     operand: &Operand<'tcx>,
 ) -> Option<&'tcx Const<'tcx>> {
     match operand {
         Operand::Copy(_) | Operand::Move(_) => None,
-        Operand::Constant(const_) => {
-            Some(fx.monomorphize(&const_.literal).eval(fx.tcx, ParamEnv::reveal_all()))
-        }
+        Operand::Constant(const_) => Some(
+            fx.monomorphize(const_.literal)
+                .eval(fx.tcx, ParamEnv::reveal_all()),
+        ),
     }
 }