Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 955 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/base.rs b/compiler/rustc_codegen_cranelift/src/base.rs
new file mode 100644
index 000000000..122e103ff
--- /dev/null
+++ b/compiler/rustc_codegen_cranelift/src/base.rs
@@ -0,0 +1,955 @@
+//! Codegen of a single function
+
+use rustc_ast::InlineAsmOptions;
+use rustc_index::vec::IndexVec;
+use rustc_middle::ty::adjustment::PointerCast;
+use rustc_middle::ty::layout::FnAbiOf;
+use rustc_middle::ty::print::with_no_trimmed_paths;
+
+use indexmap::IndexSet;
+
+use crate::constant::ConstantCx;
+use crate::prelude::*;
+use crate::pretty_clif::CommentWriter;
+
+pub(crate) fn codegen_fn<'tcx>(
+    cx: &mut crate::CodegenCx<'tcx>,
+    module: &mut dyn Module,
+    instance: Instance<'tcx>,
+) {
+    let tcx = cx.tcx;
+
+    let _inst_guard =
+        crate::PrintOnPanic(|| format!("{:?} {}", instance, tcx.symbol_name(instance).name));
+    debug_assert!(!instance.substs.needs_infer());
+
+    let mir = tcx.instance_mir(instance.def);
+    let _mir_guard = crate::PrintOnPanic(|| {
+        let mut buf = Vec::new();
+        with_no_trimmed_paths!({
+            rustc_middle::mir::pretty::write_mir_fn(tcx, mir, &mut |_, _| Ok(()), &mut buf)
+                .unwrap();
+        });
+        String::from_utf8_lossy(&buf).into_owned()
+    });
+
+    // Declare function
+    let symbol_name = tcx.symbol_name(instance);
+    let sig = get_function_sig(tcx, module.isa().triple(), instance);
+    let func_id = module.declare_function(symbol_name.name, Linkage::Local, &sig).unwrap();
+
+    cx.cached_context.clear();
+
+    // Make the FunctionBuilder
+    let mut func_ctx = FunctionBuilderContext::new();
+    let mut func = std::mem::replace(&mut cx.cached_context.func, Function::new());
+    func.name = ExternalName::user(0, func_id.as_u32());
+    func.signature = sig;
+    func.collect_debug_info();
+
+    let mut bcx = FunctionBuilder::new(&mut func, &mut func_ctx);
+
+    // Predefine blocks
+    let start_block = bcx.create_block();
+    let block_map: IndexVec<BasicBlock, Block> =
+        (0..mir.basic_blocks().len()).map(|_| bcx.create_block()).collect();
+
+    // Make FunctionCx
+    let target_config = module.target_config();
+    let pointer_type = target_config.pointer_type();
+    let clif_comments = crate::pretty_clif::CommentWriter::new(tcx, instance);
+
+    let mut fx = FunctionCx {
+        cx,
+        module,
+        tcx,
+        target_config,
+        pointer_type,
+        constants_cx: ConstantCx::new(),
+
+        instance,
+        symbol_name,
+        mir,
+        fn_abi: Some(RevealAllLayoutCx(tcx).fn_abi_of_instance(instance, ty::List::empty())),
+
+        bcx,
+        block_map,
+        local_map: IndexVec::with_capacity(mir.local_decls.len()),
+        caller_location: None, // set by `codegen_fn_prelude`
+
+        clif_comments,
+        source_info_set: indexmap::IndexSet::new(),
+        next_ssa_var: 0,
+    };
+
+    let arg_uninhabited = fx
+        .mir
+        .args_iter()
+        .any(|arg| fx.layout_of(fx.monomorphize(fx.mir.local_decls[arg].ty)).abi.is_uninhabited());
+
+    if !crate::constant::check_constants(&mut fx) {
+        fx.bcx.append_block_params_for_function_params(fx.block_map[START_BLOCK]);
+        fx.bcx.switch_to_block(fx.block_map[START_BLOCK]);
+        crate::trap::trap_unreachable(&mut fx, "compilation should have been aborted");
+    } else if arg_uninhabited {
+        fx.bcx.append_block_params_for_function_params(fx.block_map[START_BLOCK]);
+        fx.bcx.switch_to_block(fx.block_map[START_BLOCK]);
+        fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
+    } else {
+        tcx.sess.time("codegen clif ir", || {
+            tcx.sess
+                .time("codegen prelude", || crate::abi::codegen_fn_prelude(&mut fx, start_block));
+            codegen_fn_content(&mut fx);
+        });
+    }
+
+    // Recover all necessary data from fx, before accessing func will prevent future access to it.
+    let instance = fx.instance;
+    let clif_comments = fx.clif_comments;
+    let source_info_set = fx.source_info_set;
+    let local_map = fx.local_map;
+
+    fx.constants_cx.finalize(fx.tcx, &mut *fx.module);
+
+    crate::pretty_clif::write_clif_file(
+        tcx,
+        "unopt",
+        module.isa(),
+        instance,
+        &func,
+        &clif_comments,
+    );
+
+    // Verify function
+    verify_func(tcx, &clif_comments, &func);
+
+    compile_fn(
+        cx,
+        module,
+        instance,
+        symbol_name.name,
+        func_id,
+        func,
+        clif_comments,
+        source_info_set,
+        local_map,
+    );
+}
+
+fn compile_fn<'tcx>(
+    cx: &mut crate::CodegenCx<'tcx>,
+    module: &mut dyn Module,
+    instance: Instance<'tcx>,
+    symbol_name: &str,
+    func_id: FuncId,
+    func: Function,
+    mut clif_comments: CommentWriter,
+    source_info_set: IndexSet<SourceInfo>,
+    local_map: IndexVec<mir::Local, CPlace<'tcx>>,
+) {
+    let tcx = cx.tcx;
+
+    // Store function in context
+    let context = &mut cx.cached_context;
+    context.clear();
+    context.func = func;
+
+    // If the return block is not reachable, then the SSA builder may have inserted an `iconst.i128`
+    // instruction, which doesn't have an encoding.
+    context.compute_cfg();
+    context.compute_domtree();
+    context.eliminate_unreachable_code(module.isa()).unwrap();
+    context.dce(module.isa()).unwrap();
+    // Some Cranelift optimizations expect the domtree to not yet be computed and as such don't
+    // invalidate it when it would change.
+    context.domtree.clear();
+
+    // Perform rust specific optimizations
+    tcx.sess.time("optimize clif ir", || {
+        crate::optimize::optimize_function(
+            tcx,
+            module.isa(),
+            instance,
+            context,
+            &mut clif_comments,
+        );
+    });
+
+    #[cfg(any())] // This is never true
+    let _clif_guard = {
+        use std::fmt::Write;
+
+        let func_clone = context.func.clone();
+        let clif_comments_clone = clif_comments.clone();
+        let mut clif = String::new();
+        for flag in module.isa().flags().iter() {
+            writeln!(clif, "set {}", flag).unwrap();
+        }
+        write!(clif, "target {}", module.isa().triple().architecture.to_string()).unwrap();
+        for isa_flag in module.isa().isa_flags().iter() {
+            write!(clif, " {}", isa_flag).unwrap();
+        }
+        writeln!(clif, "\n").unwrap();
+        crate::PrintOnPanic(move || {
+            let mut clif = clif.clone();
+            ::cranelift_codegen::write::decorate_function(
+                &mut &clif_comments_clone,
+                &mut clif,
+                &func_clone,
+            )
+            .unwrap();
+            clif
+        })
+    };
+
+    // Define function
+    tcx.sess.time("define function", || {
+        context.want_disasm = crate::pretty_clif::should_write_ir(tcx);
+        module.define_function(func_id, context).unwrap();
+    });
+
+    // Write optimized function to file for debugging
+    crate::pretty_clif::write_clif_file(
+        tcx,
+        "opt",
+        module.isa(),
+        instance,
+        &context.func,
+        &clif_comments,
+    );
+
+    if let Some(disasm) = &context.mach_compile_result.as_ref().unwrap().disasm {
+        crate::pretty_clif::write_ir_file(
+            tcx,
+            || format!("{}.vcode", tcx.symbol_name(instance).name),
+            |file| file.write_all(disasm.as_bytes()),
+        )
+    }
+
+    // Define debuginfo for function
+    let isa = module.isa();
+    let debug_context = &mut cx.debug_context;
+    let unwind_context = &mut cx.unwind_context;
+    tcx.sess.time("generate debug info", || {
+        if let Some(debug_context) = debug_context {
+            debug_context.define_function(
+                instance,
+                func_id,
+                symbol_name,
+                isa,
+                context,
+                &source_info_set,
+                local_map,
+            );
+        }
+        unwind_context.add_function(func_id, &context, isa);
+    });
+}
+
+pub(crate) fn verify_func(
+    tcx: TyCtxt<'_>,
+    writer: &crate::pretty_clif::CommentWriter,
+    func: &Function,
+) {
+    tcx.sess.time("verify clif ir", || {
+        let flags = cranelift_codegen::settings::Flags::new(cranelift_codegen::settings::builder());
+        match cranelift_codegen::verify_function(&func, &flags) {
+            Ok(_) => {}
+            Err(err) => {
+                tcx.sess.err(&format!("{:?}", err));
+                let pretty_error = cranelift_codegen::print_errors::pretty_verifier_error(
+                    &func,
+                    Some(Box::new(writer)),
+                    err,
+                );
+                tcx.sess.fatal(&format!("cranelift verify error:\n{}", pretty_error));
+            }
+        }
+    });
+}
+
+fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, '_>) {
+    for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
+        let block = fx.get_block(bb);
+        fx.bcx.switch_to_block(block);
+
+        if bb_data.is_cleanup {
+            // Unwinding after panicking is not supported
+            continue;
+
+            // FIXME Once unwinding is supported and Cranelift supports marking blocks as cold, do
+            // so for cleanup blocks.
+        }
+
+        fx.bcx.ins().nop();
+        for stmt in &bb_data.statements {
+            fx.set_debug_loc(stmt.source_info);
+            codegen_stmt(fx, block, stmt);
+        }
+
+        if fx.clif_comments.enabled() {
+            let mut terminator_head = "\n".to_string();
+            with_no_trimmed_paths!({
+                bb_data.terminator().kind.fmt_head(&mut terminator_head).unwrap();
+            });
+            let inst = fx.bcx.func.layout.last_inst(block).unwrap();
+            fx.add_comment(inst, terminator_head);
+        }
+
+        let source_info = bb_data.terminator().source_info;
+        fx.set_debug_loc(source_info);
+
+        match &bb_data.terminator().kind {
+            TerminatorKind::Goto { target } => {
+                if let TerminatorKind::Return = fx.mir[*target].terminator().kind {
+                    let mut can_immediately_return = true;
+                    for stmt in &fx.mir[*target].statements {
+                        if let StatementKind::StorageDead(_) = stmt.kind {
+                        } else {
+                            // FIXME Can sometimes happen, see rust-lang/rust#70531
+                            can_immediately_return = false;
+                            break;
+                        }
+                    }
+
+                    if can_immediately_return {
+                        crate::abi::codegen_return(fx);
+                        continue;
+                    }
+                }
+
+                let block = fx.get_block(*target);
+                fx.bcx.ins().jump(block, &[]);
+            }
+            TerminatorKind::Return => {
+                crate::abi::codegen_return(fx);
+            }
+            TerminatorKind::Assert { cond, expected, msg, target, cleanup: _ } => {
+                if !fx.tcx.sess.overflow_checks() {
+                    if let mir::AssertKind::OverflowNeg(_) = *msg {
+                        let target = fx.get_block(*target);
+                        fx.bcx.ins().jump(target, &[]);
+                        continue;
+                    }
+                }
+                let cond = codegen_operand(fx, cond).load_scalar(fx);
+
+                let target = fx.get_block(*target);
+                let failure = fx.bcx.create_block();
+                fx.bcx.set_cold_block(failure);
+
+                if *expected {
+                    fx.bcx.ins().brz(cond, failure, &[]);
+                } else {
+                    fx.bcx.ins().brnz(cond, failure, &[]);
+                };
+                fx.bcx.ins().jump(target, &[]);
+
+                fx.bcx.switch_to_block(failure);
+                fx.bcx.ins().nop();
+
+                match msg {
+                    AssertKind::BoundsCheck { ref len, ref index } => {
+                        let len = codegen_operand(fx, len).load_scalar(fx);
+                        let index = codegen_operand(fx, index).load_scalar(fx);
+                        let location = fx.get_caller_location(source_info).load_scalar(fx);
+
+                        codegen_panic_inner(
+                            fx,
+                            rustc_hir::LangItem::PanicBoundsCheck,
+                            &[index, len, location],
+                            source_info.span,
+                        );
+                    }
+                    _ => {
+                        let msg_str = msg.description();
+                        codegen_panic(fx, msg_str, source_info);
+                    }
+                }
+            }
+
+            TerminatorKind::SwitchInt { discr, switch_ty, targets } => {
+                let discr = codegen_operand(fx, discr).load_scalar(fx);
+
+                let use_bool_opt = switch_ty.kind() == fx.tcx.types.bool.kind()
+                    || (targets.iter().count() == 1 && targets.iter().next().unwrap().0 == 0);
+                if use_bool_opt {
+                    assert_eq!(targets.iter().count(), 1);
+                    let (then_value, then_block) = targets.iter().next().unwrap();
+                    let then_block = fx.get_block(then_block);
+                    let else_block = fx.get_block(targets.otherwise());
+                    let test_zero = match then_value {
+                        0 => true,
+                        1 => false,
+                        _ => unreachable!("{:?}", targets),
+                    };
+
+                    let discr = crate::optimize::peephole::maybe_unwrap_bint(&mut fx.bcx, discr);
+                    let (discr, is_inverted) =
+                        crate::optimize::peephole::maybe_unwrap_bool_not(&mut fx.bcx, discr);
+                    let test_zero = if is_inverted { !test_zero } else { test_zero };
+                    let discr = crate::optimize::peephole::maybe_unwrap_bint(&mut fx.bcx, discr);
+                    if let Some(taken) = crate::optimize::peephole::maybe_known_branch_taken(
+                        &fx.bcx, discr, test_zero,
+                    ) {
+                        if taken {
+                            fx.bcx.ins().jump(then_block, &[]);
+                        } else {
+                            fx.bcx.ins().jump(else_block, &[]);
+                        }
+                    } else {
+                        if test_zero {
+                            fx.bcx.ins().brz(discr, then_block, &[]);
+                            fx.bcx.ins().jump(else_block, &[]);
+                        } else {
+                            fx.bcx.ins().brnz(discr, then_block, &[]);
+                            fx.bcx.ins().jump(else_block, &[]);
+                        }
+                    }
+                } else {
+                    let mut switch = ::cranelift_frontend::Switch::new();
+                    for (value, block) in targets.iter() {
+                        let block = fx.get_block(block);
+                        switch.set_entry(value, block);
+                    }
+                    let otherwise_block = fx.get_block(targets.otherwise());
+                    switch.emit(&mut fx.bcx, discr, otherwise_block);
+                }
+            }
+            TerminatorKind::Call {
+                func,
+                args,
+                destination,
+                target,
+                fn_span,
+                cleanup: _,
+                from_hir_call: _,
+            } => {
+                fx.tcx.sess.time("codegen call", || {
+                    crate::abi::codegen_terminator_call(
+                        fx,
+                        mir::SourceInfo { span: *fn_span, ..source_info },
+                        func,
+                        args,
+                        *destination,
+                        *target,
+                    )
+                });
+            }
+            TerminatorKind::InlineAsm {
+                template,
+                operands,
+                options,
+                destination,
+                line_spans: _,
+                cleanup: _,
+            } => {
+                if options.contains(InlineAsmOptions::MAY_UNWIND) {
+                    fx.tcx.sess.span_fatal(
+                        source_info.span,
+                        "cranelift doesn't support unwinding from inline assembly.",
+                    );
+                }
+
+                crate::inline_asm::codegen_inline_asm(
+                    fx,
+                    source_info.span,
+                    template,
+                    operands,
+                    *options,
+                );
+
+                match *destination {
+                    Some(destination) => {
+                        let destination_block = fx.get_block(destination);
+                        fx.bcx.ins().jump(destination_block, &[]);
+                    }
+                    None => {
+                        fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
+                    }
+                }
+            }
+            TerminatorKind::Resume | TerminatorKind::Abort => {
+                // FIXME implement unwinding
+                fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
+            }
+            TerminatorKind::Unreachable => {
+                fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
+            }
+            TerminatorKind::Yield { .. }
+            | TerminatorKind::FalseEdge { .. }
+            | TerminatorKind::FalseUnwind { .. }
+            | TerminatorKind::DropAndReplace { .. }
+            | TerminatorKind::GeneratorDrop => {
+                bug!("shouldn't exist at codegen {:?}", bb_data.terminator());
+            }
+            TerminatorKind::Drop { place, target, unwind: _ } => {
+                let drop_place = codegen_place(fx, *place);
+                crate::abi::codegen_drop(fx, source_info, drop_place);
+
+                let target_block = fx.get_block(*target);
+                fx.bcx.ins().jump(target_block, &[]);
+            }
+        };
+    }
+
+    fx.bcx.seal_all_blocks();
+    fx.bcx.finalize();
+}
+
+fn codegen_stmt<'tcx>(
+    fx: &mut FunctionCx<'_, '_, 'tcx>,
+    #[allow(unused_variables)] cur_block: Block,
+    stmt: &Statement<'tcx>,
+) {
+    let _print_guard = crate::PrintOnPanic(|| format!("stmt {:?}", stmt));
+
+    fx.set_debug_loc(stmt.source_info);
+
+    #[cfg(any())] // This is never true
+    match &stmt.kind {
+        StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
+        _ => {
+            if fx.clif_comments.enabled() {
+                let inst = fx.bcx.func.layout.last_inst(cur_block).unwrap();
+                fx.add_comment(inst, format!("{:?}", stmt));
+            }
+        }
+    }
+
+    match &stmt.kind {
+        StatementKind::SetDiscriminant { place, variant_index } => {
+            let place = codegen_place(fx, **place);
+            crate::discriminant::codegen_set_discriminant(fx, place, *variant_index);
+        }
+        StatementKind::Assign(to_place_and_rval) => {
+            let lval = codegen_place(fx, to_place_and_rval.0);
+            let dest_layout = lval.layout();
+            match to_place_and_rval.1 {
+                Rvalue::Use(ref operand) => {
+                    let val = codegen_operand(fx, operand);
+                    lval.write_cvalue(fx, val);
+                }
+                Rvalue::CopyForDeref(place) => {
+                    let cplace = codegen_place(fx, place);
+                    let val = cplace.to_cvalue(fx);
+                    lval.write_cvalue(fx, val)
+                }
+                Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
+                    let place = codegen_place(fx, place);
+                    let ref_ = place.place_ref(fx, lval.layout());
+                    lval.write_cvalue(fx, ref_);
+                }
+                Rvalue::ThreadLocalRef(def_id) => {
+                    let val = crate::constant::codegen_tls_ref(fx, def_id, lval.layout());
+                    lval.write_cvalue(fx, val);
+                }
+                Rvalue::BinaryOp(bin_op, ref lhs_rhs) => {
+                    let lhs = codegen_operand(fx, &lhs_rhs.0);
+                    let rhs = codegen_operand(fx, &lhs_rhs.1);
+
+                    let res = crate::num::codegen_binop(fx, bin_op, lhs, rhs);
+                    lval.write_cvalue(fx, res);
+                }
+                Rvalue::CheckedBinaryOp(bin_op, ref lhs_rhs) => {
+                    let lhs = codegen_operand(fx, &lhs_rhs.0);
+                    let rhs = codegen_operand(fx, &lhs_rhs.1);
+
+                    let res = if !fx.tcx.sess.overflow_checks() {
+                        let val =
+                            crate::num::codegen_int_binop(fx, bin_op, lhs, rhs).load_scalar(fx);
+                        let is_overflow = fx.bcx.ins().iconst(types::I8, 0);
+                        CValue::by_val_pair(val, is_overflow, lval.layout())
+                    } else {
+                        crate::num::codegen_checked_int_binop(fx, bin_op, lhs, rhs)
+                    };
+
+                    lval.write_cvalue(fx, res);
+                }
+                Rvalue::UnaryOp(un_op, ref operand) => {
+                    let operand = codegen_operand(fx, operand);
+                    let layout = operand.layout();
+                    let val = operand.load_scalar(fx);
+                    let res = match un_op {
+                        UnOp::Not => match layout.ty.kind() {
+                            ty::Bool => {
+                                let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
+                                CValue::by_val(fx.bcx.ins().bint(types::I8, res), layout)
+                            }
+                            ty::Uint(_) | ty::Int(_) => {
+                                CValue::by_val(fx.bcx.ins().bnot(val), layout)
+                            }
+                            _ => unreachable!("un op Not for {:?}", layout.ty),
+                        },
+                        UnOp::Neg => match layout.ty.kind() {
+                            ty::Int(IntTy::I128) => {
+                                // FIXME remove this case once ineg.i128 works
+                                let zero =
+                                    CValue::const_val(fx, layout, ty::ScalarInt::null(layout.size));
+                                crate::num::codegen_int_binop(fx, BinOp::Sub, zero, operand)
+                            }
+                            ty::Int(_) => CValue::by_val(fx.bcx.ins().ineg(val), layout),
+                            ty::Float(_) => CValue::by_val(fx.bcx.ins().fneg(val), layout),
+                            _ => unreachable!("un op Neg for {:?}", layout.ty),
+                        },
+                    };
+                    lval.write_cvalue(fx, res);
+                }
+                Rvalue::Cast(
+                    CastKind::Pointer(PointerCast::ReifyFnPointer),
+                    ref operand,
+                    to_ty,
+                ) => {
+                    let from_ty = fx.monomorphize(operand.ty(&fx.mir.local_decls, fx.tcx));
+                    let to_layout = fx.layout_of(fx.monomorphize(to_ty));
+                    match *from_ty.kind() {
+                        ty::FnDef(def_id, substs) => {
+                            let func_ref = fx.get_function_ref(
+                                Instance::resolve_for_fn_ptr(
+                                    fx.tcx,
+                                    ParamEnv::reveal_all(),
+                                    def_id,
+                                    substs,
+                                )
+                                .unwrap()
+                                .polymorphize(fx.tcx),
+                            );
+                            let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
+                            lval.write_cvalue(fx, CValue::by_val(func_addr, to_layout));
+                        }
+                        _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", from_ty),
+                    }
+                }
+                Rvalue::Cast(
+                    CastKind::Pointer(PointerCast::UnsafeFnPointer),
+                    ref operand,
+                    to_ty,
+                )
+                | Rvalue::Cast(
+                    CastKind::Pointer(PointerCast::MutToConstPointer),
+                    ref operand,
+                    to_ty,
+                )
+                | Rvalue::Cast(
+                    CastKind::Pointer(PointerCast::ArrayToPointer),
+                    ref operand,
+                    to_ty,
+                ) => {
+                    let to_layout = fx.layout_of(fx.monomorphize(to_ty));
+                    let operand = codegen_operand(fx, operand);
+                    lval.write_cvalue(fx, operand.cast_pointer_to(to_layout));
+                }
+                Rvalue::Cast(
+                    CastKind::Misc
+                    | CastKind::PointerExposeAddress
+                    | CastKind::PointerFromExposedAddress,
+                    ref operand,
+                    to_ty,
+                ) => {
+                    let operand = codegen_operand(fx, operand);
+                    let from_ty = operand.layout().ty;
+                    let to_ty = fx.monomorphize(to_ty);
+
+                    fn is_fat_ptr<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> bool {
+                        ty.builtin_deref(true)
+                            .map(|ty::TypeAndMut { ty: pointee_ty, mutbl: _ }| {
+                                has_ptr_meta(fx.tcx, pointee_ty)
+                            })
+                            .unwrap_or(false)
+                    }
+
+                    if is_fat_ptr(fx, from_ty) {
+                        if is_fat_ptr(fx, to_ty) {
+                            // fat-ptr -> fat-ptr
+                            lval.write_cvalue(fx, operand.cast_pointer_to(dest_layout));
+                        } else {
+                            // fat-ptr -> thin-ptr
+                            let (ptr, _extra) = operand.load_scalar_pair(fx);
+                            lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
+                        }
+                    } else {
+                        let to_clif_ty = fx.clif_type(to_ty).unwrap();
+                        let from = operand.load_scalar(fx);
+
+                        let res = clif_int_or_float_cast(
+                            fx,
+                            from,
+                            type_sign(from_ty),
+                            to_clif_ty,
+                            type_sign(to_ty),
+                        );
+                        lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
+                    }
+                }
+                Rvalue::Cast(
+                    CastKind::Pointer(PointerCast::ClosureFnPointer(_)),
+                    ref operand,
+                    _to_ty,
+                ) => {
+                    let operand = codegen_operand(fx, operand);
+                    match *operand.layout().ty.kind() {
+                        ty::Closure(def_id, substs) => {
+                            let instance = Instance::resolve_closure(
+                                fx.tcx,
+                                def_id,
+                                substs,
+                                ty::ClosureKind::FnOnce,
+                            )
+                            .expect("failed to normalize and resolve closure during codegen")
+                            .polymorphize(fx.tcx);
+                            let func_ref = fx.get_function_ref(instance);
+                            let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
+                            lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
+                        }
+                        _ => bug!("{} cannot be cast to a fn ptr", operand.layout().ty),
+                    }
+                }
+                Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), ref operand, _to_ty) => {
+                    let operand = codegen_operand(fx, operand);
+                    operand.unsize_value(fx, lval);
+                }
+                Rvalue::Discriminant(place) => {
+                    let place = codegen_place(fx, place);
+                    let value = place.to_cvalue(fx);
+                    let discr =
+                        crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
+                    lval.write_cvalue(fx, discr);
+                }
+                Rvalue::Repeat(ref operand, times) => {
+                    let operand = codegen_operand(fx, operand);
+                    let times = fx
+                        .monomorphize(times)
+                        .eval(fx.tcx, ParamEnv::reveal_all())
+                        .kind()
+                        .try_to_bits(fx.tcx.data_layout.pointer_size)
+                        .unwrap();
+                    if operand.layout().size.bytes() == 0 {
+                        // Do nothing for ZST's
+                    } else if fx.clif_type(operand.layout().ty) == Some(types::I8) {
+                        let times = fx.bcx.ins().iconst(fx.pointer_type, times as i64);
+                        // FIXME use emit_small_memset where possible
+                        let addr = lval.to_ptr().get_addr(fx);
+                        let val = operand.load_scalar(fx);
+                        fx.bcx.call_memset(fx.target_config, addr, val, times);
+                    } else {
+                        let loop_block = fx.bcx.create_block();
+                        let loop_block2 = fx.bcx.create_block();
+                        let done_block = fx.bcx.create_block();
+                        let index = fx.bcx.append_block_param(loop_block, fx.pointer_type);
+                        let zero = fx.bcx.ins().iconst(fx.pointer_type, 0);
+                        fx.bcx.ins().jump(loop_block, &[zero]);
+
+                        fx.bcx.switch_to_block(loop_block);
+                        let done = fx.bcx.ins().icmp_imm(IntCC::Equal, index, times as i64);
+                        fx.bcx.ins().brnz(done, done_block, &[]);
+                        fx.bcx.ins().jump(loop_block2, &[]);
+
+                        fx.bcx.switch_to_block(loop_block2);
+                        let to = lval.place_index(fx, index);
+                        to.write_cvalue(fx, operand);
+                        let index = fx.bcx.ins().iadd_imm(index, 1);
+                        fx.bcx.ins().jump(loop_block, &[index]);
+
+                        fx.bcx.switch_to_block(done_block);
+                        fx.bcx.ins().nop();
+                    }
+                }
+                Rvalue::Len(place) => {
+                    let place = codegen_place(fx, place);
+                    let usize_layout = fx.layout_of(fx.tcx.types.usize);
+                    let len = codegen_array_len(fx, place);
+                    lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
+                }
+                Rvalue::ShallowInitBox(ref operand, content_ty) => {
+                    let content_ty = fx.monomorphize(content_ty);
+                    let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
+                    let operand = codegen_operand(fx, operand);
+                    let operand = operand.load_scalar(fx);
+                    lval.write_cvalue(fx, CValue::by_val(operand, box_layout));
+                }
+                Rvalue::NullaryOp(null_op, ty) => {
+                    assert!(
+                        lval.layout()
+                            .ty
+                            .is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all())
+                    );
+                    let layout = fx.layout_of(fx.monomorphize(ty));
+                    let val = match null_op {
+                        NullOp::SizeOf => layout.size.bytes(),
+                        NullOp::AlignOf => layout.align.abi.bytes(),
+                    };
+                    let val = CValue::const_val(fx, fx.layout_of(fx.tcx.types.usize), val.into());
+                    lval.write_cvalue(fx, val);
+                }
+                Rvalue::Aggregate(ref kind, ref operands) => match kind.as_ref() {
+                    AggregateKind::Array(_ty) => {
+                        for (i, operand) in operands.iter().enumerate() {
+                            let operand = codegen_operand(fx, operand);
+                            let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
+                            let to = lval.place_index(fx, index);
+                            to.write_cvalue(fx, operand);
+                        }
+                    }
+                    _ => unreachable!("shouldn't exist at codegen {:?}", to_place_and_rval.1),
+                },
+            }
+        }
+        StatementKind::StorageLive(_)
+        | StatementKind::StorageDead(_)
+        | StatementKind::Deinit(_)
+        | StatementKind::Nop
+        | StatementKind::FakeRead(..)
+        | StatementKind::Retag { .. }
+        | StatementKind::AscribeUserType(..) => {}
+
+        StatementKind::Coverage { .. } => fx.tcx.sess.fatal("-Zcoverage is unimplemented"),
+        StatementKind::CopyNonOverlapping(inner) => {
+            let dst = codegen_operand(fx, &inner.dst);
+            let pointee = dst
+                .layout()
+                .pointee_info_at(fx, rustc_target::abi::Size::ZERO)
+                .expect("Expected pointer");
+            let dst = dst.load_scalar(fx);
+            let src = codegen_operand(fx, &inner.src).load_scalar(fx);
+            let count = codegen_operand(fx, &inner.count).load_scalar(fx);
+            let elem_size: u64 = pointee.size.bytes();
+            let bytes =
+                if elem_size != 1 { fx.bcx.ins().imul_imm(count, elem_size as i64) } else { count };
+            fx.bcx.call_memcpy(fx.target_config, dst, src, bytes);
+        }
+    }
+}
+
+fn codegen_array_len<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, place: CPlace<'tcx>) -> Value {
+    match *place.layout().ty.kind() {
+        ty::Array(_elem_ty, len) => {
+            let len = fx.monomorphize(len).eval_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
+            fx.bcx.ins().iconst(fx.pointer_type, len)
+        }
+        ty::Slice(_elem_ty) => {
+            place.to_ptr_maybe_unsized().1.expect("Length metadata for slice place")
+        }
+        _ => bug!("Rvalue::Len({:?})", place),
+    }
+}
+
+pub(crate) fn codegen_place<'tcx>(
+    fx: &mut FunctionCx<'_, '_, 'tcx>,
+    place: Place<'tcx>,
+) -> CPlace<'tcx> {
+    let mut cplace = fx.get_local_place(place.local);
+
+    for elem in place.projection {
+        match elem {
+            PlaceElem::Deref => {
+                cplace = cplace.place_deref(fx);
+            }
+            PlaceElem::Field(field, _ty) => {
+                cplace = cplace.place_field(fx, field);
+            }
+            PlaceElem::Index(local) => {
+                let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
+                cplace = cplace.place_index(fx, index);
+            }
+            PlaceElem::ConstantIndex { offset, min_length: _, from_end } => {
+                let offset: u64 = offset;
+                let index = if !from_end {
+                    fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
+                } else {
+                    let len = codegen_array_len(fx, cplace);
+                    fx.bcx.ins().iadd_imm(len, -(offset as i64))
+                };
+                cplace = cplace.place_index(fx, index);
+            }
+            PlaceElem::Subslice { from, to, from_end } => {
+                // These indices are generated by slice patterns.
+                // slice[from:-to] in Python terms.
+
+                let from: u64 = from;
+                let to: u64 = to;
+
+                match cplace.layout().ty.kind() {
+                    ty::Array(elem_ty, _len) => {
+                        assert!(!from_end, "array subslices are never `from_end`");
+                        let elem_layout = fx.layout_of(*elem_ty);
+                        let ptr = cplace.to_ptr();
+                        cplace = CPlace::for_ptr(
+                            ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * (from as i64)),
+                            fx.layout_of(fx.tcx.mk_array(*elem_ty, to - from)),
+                        );
+                    }
+                    ty::Slice(elem_ty) => {
+                        assert!(from_end, "slice subslices should be `from_end`");
+                        let elem_layout = fx.layout_of(*elem_ty);
+                        let (ptr, len) = cplace.to_ptr_maybe_unsized();
+                        let len = len.unwrap();
+                        cplace = CPlace::for_ptr_with_extra(
+                            ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * (from as i64)),
+                            fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
+                            cplace.layout(),
+                        );
+                    }
+                    _ => unreachable!(),
+                }
+            }
+            PlaceElem::Downcast(_adt_def, variant) => {
+                cplace = cplace.downcast_variant(fx, variant);
+            }
+        }
+    }
+
+    cplace
+}
+
+pub(crate) fn codegen_operand<'tcx>(
+    fx: &mut FunctionCx<'_, '_, 'tcx>,
+    operand: &Operand<'tcx>,
+) -> CValue<'tcx> {
+    match operand {
+        Operand::Move(place) | Operand::Copy(place) => {
+            let cplace = codegen_place(fx, *place);
+            cplace.to_cvalue(fx)
+        }
+        Operand::Constant(const_) => crate::constant::codegen_constant(fx, const_),
+    }
+}
+
+pub(crate) fn codegen_panic<'tcx>(
+    fx: &mut FunctionCx<'_, '_, 'tcx>,
+    msg_str: &str,
+    source_info: mir::SourceInfo,
+) {
+    let location = fx.get_caller_location(source_info).load_scalar(fx);
+
+    let msg_ptr = fx.anonymous_str(msg_str);
+    let msg_len = fx.bcx.ins().iconst(fx.pointer_type, i64::try_from(msg_str.len()).unwrap());
+    let args = [msg_ptr, msg_len, location];
+
+    codegen_panic_inner(fx, rustc_hir::LangItem::Panic, &args, source_info.span);
+}
+
+pub(crate) fn codegen_panic_inner<'tcx>(
+    fx: &mut FunctionCx<'_, '_, 'tcx>,
+    lang_item: rustc_hir::LangItem,
+    args: &[Value],
+    span: Span,
+) {
+    let def_id =
+        fx.tcx.lang_items().require(lang_item).unwrap_or_else(|s| fx.tcx.sess.span_fatal(span, &s));
+
+    let instance = Instance::mono(fx.tcx, def_id).polymorphize(fx.tcx);
+    let symbol_name = fx.tcx.symbol_name(instance).name;
+
+    fx.lib_call(
+        &*symbol_name,
+        vec![
+            AbiParam::new(fx.pointer_type),
+            AbiParam::new(fx.pointer_type),
+            AbiParam::new(fx.pointer_type),
+        ],
+        vec![],
+        args,
+    );
+
+    fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
+}