rust/compiler/rustc_codegen_cranelift/src/base.rs

921 lines
38 KiB
Rust

//! 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);
let discr =
crate::optimize::peephole::make_branchable_value(&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");
}