diff options
Diffstat (limited to 'compiler/rustc_codegen_cranelift/src/base.rs')
| -rw-r--r-- | compiler/rustc_codegen_cranelift/src/base.rs | 918 |
1 files changed, 918 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 00000000000..e99a227a3a6 --- /dev/null +++ b/compiler/rustc_codegen_cranelift/src/base.rs @@ -0,0 +1,918 @@ +//! Codegen of a single function + +use cranelift_codegen::binemit::{NullStackMapSink, NullTrapSink}; +use rustc_index::vec::IndexVec; +use rustc_middle::ty::adjustment::PointerCast; +use rustc_middle::ty::layout::FnAbiExt; +use rustc_target::abi::call::FnAbi; + +use crate::constant::ConstantCx; +use crate::prelude::*; + +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(); + rustc_mir::util::write_mir_pretty(tcx, Some(instance.def_id()), &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 pointer_type = module.target_config().pointer_type(); + let clif_comments = crate::pretty_clif::CommentWriter::new(tcx, instance); + + let mut fx = FunctionCx { + cx, + module, + tcx, + pointer_type, + constants_cx: ConstantCx::new(), + + instance, + symbol_name, + mir, + fn_abi: Some(FnAbi::of_instance(&RevealAllLayoutCx(tcx), instance, &[])), + + 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, + + inline_asm_index: 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]); + crate::trap::trap_unreachable(&mut fx, "function has uninhabited argument"); + } 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 mut 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); + + // Store function in context + let context = &mut cx.cached_context; + context.func = func; + + crate::pretty_clif::write_clif_file( + tcx, + "unopt", + module.isa(), + instance, + &context, + &clif_comments, + ); + + // Verify function + verify_func(tcx, &clif_comments, &context.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, + ); + }); + + // Define function + tcx.sess.time("define function", || { + context.want_disasm = crate::pretty_clif::should_write_ir(tcx); + module + .define_function(func_id, context, &mut NullTrapSink {}, &mut NullStackMapSink {}) + .unwrap() + }); + + // Write optimized function to file for debugging + crate::pretty_clif::write_clif_file( + tcx, + "opt", + module.isa(), + instance, + &context, + &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.name, + isa, + context, + &source_info_set, + local_map, + ); + } + unwind_context.add_function(func_id, &context, isa); + }); + + // Clear context to make it usable for the next function + context.clear(); +} + +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, + None, + 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(); + 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); + } + + fx.set_debug_loc(bb_data.terminator().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(); + // FIXME Mark failure block as cold once Cranelift supports it + + 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(bb_data.terminator().source_info.span) + .load_scalar(fx); + + codegen_panic_inner( + fx, + rustc_hir::LangItem::PanicBoundsCheck, + &[index, len, location], + bb_data.terminator().source_info.span, + ); + } + _ => { + let msg_str = msg.description(); + codegen_panic(fx, msg_str, bb_data.terminator().source_info.span); + } + } + } + + 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, + fn_span, + cleanup: _, + from_hir_call: _, + } => { + fx.tcx.sess.time("codegen call", || { + crate::abi::codegen_terminator_call(fx, *fn_span, func, args, *destination) + }); + } + TerminatorKind::InlineAsm { + template, + operands, + options, + destination, + line_spans: _, + } => { + crate::inline_asm::codegen_inline_asm( + fx, + bb_data.terminator().source_info.span, + template, + operands, + *options, + ); + + match *destination { + Some(destination) => { + let destination_block = fx.get_block(destination); + fx.bcx.ins().jump(destination_block, &[]); + } + None => { + crate::trap::trap_unreachable( + fx, + "[corruption] Returned from noreturn inline asm", + ); + } + } + } + TerminatorKind::Resume | TerminatorKind::Abort => { + trap_unreachable(fx, "[corruption] Unwinding bb reached."); + } + TerminatorKind::Unreachable => { + trap_unreachable(fx, "[corruption] Hit unreachable code."); + } + 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, bb_data.terminator().source_info.span, 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(disabled)] + 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::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, 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 if let ty::Adt(adt_def, _substs) = from_ty.kind() { + // enum -> discriminant value + assert!(adt_def.is_enum()); + match to_ty.kind() { + ty::Uint(_) | ty::Int(_) => {} + _ => unreachable!("cast adt {} -> {}", from_ty, to_ty), + } + let to_clif_ty = fx.clif_type(to_ty).unwrap(); + + let discriminant = crate::discriminant::codegen_get_discriminant( + fx, + operand, + fx.layout_of(operand.layout().ty.discriminant_ty(fx.tcx)), + ) + .load_scalar(fx); + + let res = crate::cast::clif_intcast( + fx, + discriminant, + to_clif_ty, + to_ty.is_signed(), + ); + lval.write_cvalue(fx, CValue::by_val(res, 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, + ) + .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()) + .val + .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.module.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::NullaryOp(NullOp::Box, content_ty) => { + let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap(); + let content_ty = fx.monomorphize(content_ty); + let layout = fx.layout_of(content_ty); + let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64); + let llalign = fx.bcx.ins().iconst(usize_type, layout.align.abi.bytes() as i64); + let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty)); + + // Allocate space: + let def_id = + match fx.tcx.lang_items().require(rustc_hir::LangItem::ExchangeMalloc) { + Ok(id) => id, + Err(s) => { + fx.tcx + .sess + .fatal(&format!("allocation of `{}` {}", box_layout.ty, s)); + } + }; + let instance = ty::Instance::mono(fx.tcx, def_id).polymorphize(fx.tcx); + let func_ref = fx.get_function_ref(instance); + let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]); + let ptr = fx.bcx.inst_results(call)[0]; + lval.write_cvalue(fx, CValue::by_val(ptr, box_layout)); + } + Rvalue::NullaryOp(NullOp::SizeOf, ty) => { + assert!( + lval.layout() + .ty + .is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all()) + ); + let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes(); + let val = + CValue::const_val(fx, fx.layout_of(fx.tcx.types.usize), ty_size.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::Nop + | StatementKind::FakeRead(..) + | StatementKind::Retag { .. } + | StatementKind::AscribeUserType(..) => {} + + StatementKind::LlvmInlineAsm(asm) => { + match asm.asm.asm.as_str().trim() { + "" => { + // Black box + } + _ => fx.tcx.sess.span_fatal( + stmt.source_info.span, + "Legacy `llvm_asm!` inline assembly is not supported. \ + Try using the new `asm!` instead.", + ), + } + } + 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.module.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, span: Span) { + let location = fx.get_caller_location(span).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, 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, + ); + + crate::trap::trap_unreachable(fx, "panic lang item returned"); +} |