1056 lines
45 KiB
Rust
1056 lines
45 KiB
Rust
use itertools::Itertools as _;
|
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use rustc_abi::{self as abi, BackendRepr, FIRST_VARIANT};
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use rustc_middle::ty::adjustment::PointerCoercion;
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use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf, TyAndLayout};
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use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
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use rustc_middle::{bug, mir, span_bug};
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use rustc_session::config::OptLevel;
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use tracing::{debug, instrument};
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use super::FunctionCx;
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use super::operand::{OperandRef, OperandRefBuilder, OperandValue};
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use super::place::{PlaceRef, PlaceValue, codegen_tag_value};
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use crate::common::{IntPredicate, TypeKind};
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use crate::traits::*;
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use crate::{MemFlags, base};
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impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
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#[instrument(level = "trace", skip(self, bx))]
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pub(crate) fn codegen_rvalue(
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&mut self,
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bx: &mut Bx,
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dest: PlaceRef<'tcx, Bx::Value>,
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rvalue: &mir::Rvalue<'tcx>,
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) {
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match *rvalue {
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mir::Rvalue::Use(ref operand) => {
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||
if let mir::Operand::Constant(const_op) = operand {
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let val = self.eval_mir_constant(&const_op);
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if val.all_bytes_uninit(self.cx.tcx()) {
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return;
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}
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}
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let cg_operand = self.codegen_operand(bx, operand);
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// Crucially, we do *not* use `OperandValue::Ref` for types with
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// `BackendRepr::Scalar | BackendRepr::ScalarPair`. This ensures we match the MIR
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// semantics regarding when assignment operators allow overlap of LHS and RHS.
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if matches!(
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cg_operand.layout.backend_repr,
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BackendRepr::Scalar(..) | BackendRepr::ScalarPair(..),
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) {
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debug_assert!(!matches!(cg_operand.val, OperandValue::Ref(..)));
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}
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// FIXME: consider not copying constants through stack. (Fixable by codegen'ing
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// constants into `OperandValue::Ref`; why don’t we do that yet if we don’t?)
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cg_operand.store_with_annotation(bx, dest);
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}
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mir::Rvalue::Cast(
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mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _),
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ref source,
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_,
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) => {
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// The destination necessarily contains a wide pointer, so if
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// it's a scalar pair, it's a wide pointer or newtype thereof.
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if bx.cx().is_backend_scalar_pair(dest.layout) {
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// Into-coerce of a thin pointer to a wide pointer -- just
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// use the operand path.
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let temp = self.codegen_rvalue_operand(bx, rvalue);
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temp.store_with_annotation(bx, dest);
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return;
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}
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// Unsize of a nontrivial struct. I would prefer for
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// this to be eliminated by MIR building, but
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// `CoerceUnsized` can be passed by a where-clause,
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// so the (generic) MIR may not be able to expand it.
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let operand = self.codegen_operand(bx, source);
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match operand.val {
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OperandValue::Pair(..) | OperandValue::Immediate(_) => {
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// Unsize from an immediate structure. We don't
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// really need a temporary alloca here, but
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// avoiding it would require us to have
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// `coerce_unsized_into` use `extractvalue` to
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// index into the struct, and this case isn't
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// important enough for it.
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debug!("codegen_rvalue: creating ugly alloca");
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let scratch = PlaceRef::alloca(bx, operand.layout);
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scratch.storage_live(bx);
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operand.store_with_annotation(bx, scratch);
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base::coerce_unsized_into(bx, scratch, dest);
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scratch.storage_dead(bx);
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}
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OperandValue::Ref(val) => {
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if val.llextra.is_some() {
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bug!("unsized coercion on an unsized rvalue");
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}
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base::coerce_unsized_into(bx, val.with_type(operand.layout), dest);
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}
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OperandValue::ZeroSized => {
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bug!("unsized coercion on a ZST rvalue");
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}
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}
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}
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mir::Rvalue::Cast(
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mir::CastKind::Transmute | mir::CastKind::Subtype,
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ref operand,
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_ty,
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) => {
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let src = self.codegen_operand(bx, operand);
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self.codegen_transmute(bx, src, dest);
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}
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mir::Rvalue::Repeat(ref elem, count) => {
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// Do not generate the loop for zero-sized elements or empty arrays.
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if dest.layout.is_zst() {
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return;
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}
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// When the element is a const with all bytes uninit, emit a single memset that
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// writes undef to the entire destination.
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if let mir::Operand::Constant(const_op) = elem {
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let val = self.eval_mir_constant(const_op);
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if val.all_bytes_uninit(self.cx.tcx()) {
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let size = bx.const_usize(dest.layout.size.bytes());
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bx.memset(
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dest.val.llval,
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bx.const_undef(bx.type_i8()),
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size,
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dest.val.align,
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MemFlags::empty(),
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);
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return;
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}
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}
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let cg_elem = self.codegen_operand(bx, elem);
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let try_init_all_same = |bx: &mut Bx, v| {
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let start = dest.val.llval;
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let size = bx.const_usize(dest.layout.size.bytes());
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// Use llvm.memset.p0i8.* to initialize all same byte arrays
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if let Some(int) = bx.cx().const_to_opt_u128(v, false)
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&& let bytes = &int.to_le_bytes()[..cg_elem.layout.size.bytes_usize()]
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&& let Ok(&byte) = bytes.iter().all_equal_value()
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{
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let fill = bx.cx().const_u8(byte);
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bx.memset(start, fill, size, dest.val.align, MemFlags::empty());
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return true;
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}
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// Use llvm.memset.p0i8.* to initialize byte arrays
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let v = bx.from_immediate(v);
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if bx.cx().val_ty(v) == bx.cx().type_i8() {
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bx.memset(start, v, size, dest.val.align, MemFlags::empty());
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return true;
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}
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false
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};
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if let OperandValue::Immediate(v) = cg_elem.val
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&& try_init_all_same(bx, v)
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{
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return;
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}
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let count = self
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.monomorphize(count)
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.try_to_target_usize(bx.tcx())
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.expect("expected monomorphic const in codegen");
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bx.write_operand_repeatedly(cg_elem, count, dest);
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}
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// This implementation does field projection, so never use it for `RawPtr`,
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// which will always be fine with the `codegen_rvalue_operand` path below.
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mir::Rvalue::Aggregate(ref kind, ref operands)
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if !matches!(**kind, mir::AggregateKind::RawPtr(..)) =>
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{
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let (variant_index, variant_dest, active_field_index) = match **kind {
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mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => {
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let variant_dest = dest.project_downcast(bx, variant_index);
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(variant_index, variant_dest, active_field_index)
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}
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_ => (FIRST_VARIANT, dest, None),
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};
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if active_field_index.is_some() {
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assert_eq!(operands.len(), 1);
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}
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for (i, operand) in operands.iter_enumerated() {
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let op = self.codegen_operand(bx, operand);
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// Do not generate stores and GEPis for zero-sized fields.
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if !op.layout.is_zst() {
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let field_index = active_field_index.unwrap_or(i);
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let field = if let mir::AggregateKind::Array(_) = **kind {
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let llindex = bx.cx().const_usize(field_index.as_u32().into());
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variant_dest.project_index(bx, llindex)
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} else {
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variant_dest.project_field(bx, field_index.as_usize())
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};
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op.store_with_annotation(bx, field);
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}
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}
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dest.codegen_set_discr(bx, variant_index);
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}
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_ => {
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let temp = self.codegen_rvalue_operand(bx, rvalue);
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temp.store_with_annotation(bx, dest);
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}
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}
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}
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/// Transmutes the `src` value to the destination type by writing it to `dst`.
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///
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/// See also [`Self::codegen_transmute_operand`] for cases that can be done
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/// without needing a pre-allocated place for the destination.
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fn codegen_transmute(
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&mut self,
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bx: &mut Bx,
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src: OperandRef<'tcx, Bx::Value>,
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dst: PlaceRef<'tcx, Bx::Value>,
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) {
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// The MIR validator enforces no unsized transmutes.
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assert!(src.layout.is_sized());
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assert!(dst.layout.is_sized());
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if src.layout.size != dst.layout.size
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|| src.layout.is_uninhabited()
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|| dst.layout.is_uninhabited()
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{
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// These cases are all UB to actually hit, so don't emit code for them.
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// (The size mismatches are reachable via `transmute_unchecked`.)
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bx.unreachable_nonterminator();
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} else {
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// Since in this path we have a place anyway, we can store or copy to it,
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// making sure we use the destination place's alignment even if the
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// source would normally have a higher one.
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src.store_with_annotation(bx, dst.val.with_type(src.layout));
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}
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}
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/// Transmutes an `OperandValue` to another `OperandValue`.
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///
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/// This is supported for all cases where the `cast` type is SSA,
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/// but for non-ZSTs with [`abi::BackendRepr::Memory`] it ICEs.
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pub(crate) fn codegen_transmute_operand(
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&mut self,
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bx: &mut Bx,
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operand: OperandRef<'tcx, Bx::Value>,
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||
cast: TyAndLayout<'tcx>,
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||
) -> OperandValue<Bx::Value> {
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||
if let abi::BackendRepr::Memory { .. } = cast.backend_repr
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&& !cast.is_zst()
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{
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span_bug!(self.mir.span, "Use `codegen_transmute` to transmute to {cast:?}");
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}
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||
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||
// `Layout` is interned, so we can do a cheap check for things that are
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// exactly the same and thus don't need any handling.
|
||
if abi::Layout::eq(&operand.layout.layout, &cast.layout) {
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return operand.val;
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||
}
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||
|
||
// Check for transmutes that are always UB.
|
||
if operand.layout.size != cast.size
|
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|| operand.layout.is_uninhabited()
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|| cast.is_uninhabited()
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{
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bx.unreachable_nonterminator();
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||
|
||
// We still need to return a value of the appropriate type, but
|
||
// it's already UB so do the easiest thing available.
|
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return OperandValue::poison(bx, cast);
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}
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|
||
// To or from pointers takes different methods, so we use this to restrict
|
||
// the SimdVector case to types which can be `bitcast` between each other.
|
||
#[inline]
|
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fn vector_can_bitcast(x: abi::Scalar) -> bool {
|
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matches!(
|
||
x,
|
||
abi::Scalar::Initialized {
|
||
value: abi::Primitive::Int(..) | abi::Primitive::Float(..),
|
||
..
|
||
}
|
||
)
|
||
}
|
||
|
||
let cx = bx.cx();
|
||
match (operand.val, operand.layout.backend_repr, cast.backend_repr) {
|
||
_ if cast.is_zst() => OperandValue::ZeroSized,
|
||
(OperandValue::Ref(source_place_val), abi::BackendRepr::Memory { .. }, _) => {
|
||
assert_eq!(source_place_val.llextra, None);
|
||
// The existing alignment is part of `source_place_val`,
|
||
// so that alignment will be used, not `cast`'s.
|
||
bx.load_operand(source_place_val.with_type(cast)).val
|
||
}
|
||
(
|
||
OperandValue::Immediate(imm),
|
||
abi::BackendRepr::Scalar(from_scalar),
|
||
abi::BackendRepr::Scalar(to_scalar),
|
||
) if from_scalar.size(cx) == to_scalar.size(cx) => {
|
||
OperandValue::Immediate(transmute_scalar(bx, imm, from_scalar, to_scalar))
|
||
}
|
||
(
|
||
OperandValue::Immediate(imm),
|
||
abi::BackendRepr::SimdVector { element: from_scalar, .. },
|
||
abi::BackendRepr::SimdVector { element: to_scalar, .. },
|
||
) if vector_can_bitcast(from_scalar) && vector_can_bitcast(to_scalar) => {
|
||
let to_backend_ty = bx.cx().immediate_backend_type(cast);
|
||
OperandValue::Immediate(bx.bitcast(imm, to_backend_ty))
|
||
}
|
||
(
|
||
OperandValue::Pair(imm_a, imm_b),
|
||
abi::BackendRepr::ScalarPair(in_a, in_b),
|
||
abi::BackendRepr::ScalarPair(out_a, out_b),
|
||
) if in_a.size(cx) == out_a.size(cx) && in_b.size(cx) == out_b.size(cx) => {
|
||
OperandValue::Pair(
|
||
transmute_scalar(bx, imm_a, in_a, out_a),
|
||
transmute_scalar(bx, imm_b, in_b, out_b),
|
||
)
|
||
}
|
||
_ => {
|
||
// For any other potentially-tricky cases, make a temporary instead.
|
||
// If anything else wants the target local to be in memory this won't
|
||
// be hit, as `codegen_transmute` will get called directly. Thus this
|
||
// is only for places where everything else wants the operand form,
|
||
// and thus it's not worth making those places get it from memory.
|
||
//
|
||
// Notably, Scalar ⇌ ScalarPair cases go here to avoid padding
|
||
// and endianness issues, as do SimdVector ones to avoid worrying
|
||
// about things like f32x8 ⇌ ptrx4 that would need multiple steps.
|
||
let align = Ord::max(operand.layout.align.abi, cast.align.abi);
|
||
let size = Ord::max(operand.layout.size, cast.size);
|
||
let temp = PlaceValue::alloca(bx, size, align);
|
||
bx.lifetime_start(temp.llval, size);
|
||
operand.store_with_annotation(bx, temp.with_type(operand.layout));
|
||
let val = bx.load_operand(temp.with_type(cast)).val;
|
||
bx.lifetime_end(temp.llval, size);
|
||
val
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Cast one of the immediates from an [`OperandValue::Immediate`]
|
||
/// or an [`OperandValue::Pair`] to an immediate of the target type.
|
||
///
|
||
/// Returns `None` if the cast is not possible.
|
||
fn cast_immediate(
|
||
&self,
|
||
bx: &mut Bx,
|
||
mut imm: Bx::Value,
|
||
from_scalar: abi::Scalar,
|
||
from_backend_ty: Bx::Type,
|
||
to_scalar: abi::Scalar,
|
||
to_backend_ty: Bx::Type,
|
||
) -> Option<Bx::Value> {
|
||
use abi::Primitive::*;
|
||
|
||
// When scalars are passed by value, there's no metadata recording their
|
||
// valid ranges. For example, `char`s are passed as just `i32`, with no
|
||
// way for LLVM to know that they're 0x10FFFF at most. Thus we assume
|
||
// the range of the input value too, not just the output range.
|
||
assume_scalar_range(bx, imm, from_scalar, from_backend_ty, None);
|
||
|
||
imm = match (from_scalar.primitive(), to_scalar.primitive()) {
|
||
(Int(_, is_signed), Int(..)) => bx.intcast(imm, to_backend_ty, is_signed),
|
||
(Float(_), Float(_)) => {
|
||
let srcsz = bx.cx().float_width(from_backend_ty);
|
||
let dstsz = bx.cx().float_width(to_backend_ty);
|
||
if dstsz > srcsz {
|
||
bx.fpext(imm, to_backend_ty)
|
||
} else if srcsz > dstsz {
|
||
bx.fptrunc(imm, to_backend_ty)
|
||
} else {
|
||
imm
|
||
}
|
||
}
|
||
(Int(_, is_signed), Float(_)) => {
|
||
if is_signed {
|
||
bx.sitofp(imm, to_backend_ty)
|
||
} else {
|
||
bx.uitofp(imm, to_backend_ty)
|
||
}
|
||
}
|
||
(Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty),
|
||
(Int(_, is_signed), Pointer(..)) => {
|
||
let usize_imm = bx.intcast(imm, bx.cx().type_isize(), is_signed);
|
||
bx.inttoptr(usize_imm, to_backend_ty)
|
||
}
|
||
(Float(_), Int(_, is_signed)) => bx.cast_float_to_int(is_signed, imm, to_backend_ty),
|
||
_ => return None,
|
||
};
|
||
Some(imm)
|
||
}
|
||
|
||
pub(crate) fn codegen_rvalue_operand(
|
||
&mut self,
|
||
bx: &mut Bx,
|
||
rvalue: &mir::Rvalue<'tcx>,
|
||
) -> OperandRef<'tcx, Bx::Value> {
|
||
match *rvalue {
|
||
mir::Rvalue::Cast(ref kind, ref source, mir_cast_ty) => {
|
||
let operand = self.codegen_operand(bx, source);
|
||
debug!("cast operand is {:?}", operand);
|
||
let cast = bx.cx().layout_of(self.monomorphize(mir_cast_ty));
|
||
|
||
let val = match *kind {
|
||
mir::CastKind::PointerExposeProvenance => {
|
||
assert!(bx.cx().is_backend_immediate(cast));
|
||
let llptr = operand.immediate();
|
||
let llcast_ty = bx.cx().immediate_backend_type(cast);
|
||
let lladdr = bx.ptrtoint(llptr, llcast_ty);
|
||
OperandValue::Immediate(lladdr)
|
||
}
|
||
mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer(_), _) => {
|
||
match *operand.layout.ty.kind() {
|
||
ty::FnDef(def_id, args) => {
|
||
let instance = ty::Instance::resolve_for_fn_ptr(
|
||
bx.tcx(),
|
||
bx.typing_env(),
|
||
def_id,
|
||
args,
|
||
)
|
||
.unwrap();
|
||
OperandValue::Immediate(bx.get_fn_addr(instance))
|
||
}
|
||
_ => bug!("{} cannot be reified to a fn ptr", operand.layout.ty),
|
||
}
|
||
}
|
||
mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _) => {
|
||
match *operand.layout.ty.kind() {
|
||
ty::Closure(def_id, args) => {
|
||
let instance = Instance::resolve_closure(
|
||
bx.cx().tcx(),
|
||
def_id,
|
||
args,
|
||
ty::ClosureKind::FnOnce,
|
||
);
|
||
OperandValue::Immediate(bx.cx().get_fn_addr(instance))
|
||
}
|
||
_ => bug!("{} cannot be cast to a fn ptr", operand.layout.ty),
|
||
}
|
||
}
|
||
mir::CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer, _) => {
|
||
// This is a no-op at the LLVM level.
|
||
operand.val
|
||
}
|
||
mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _) => {
|
||
assert!(bx.cx().is_backend_scalar_pair(cast));
|
||
let (lldata, llextra) = operand.val.pointer_parts();
|
||
let (lldata, llextra) =
|
||
base::unsize_ptr(bx, lldata, operand.layout.ty, cast.ty, llextra);
|
||
OperandValue::Pair(lldata, llextra)
|
||
}
|
||
mir::CastKind::PointerCoercion(
|
||
PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer, _
|
||
) => {
|
||
bug!("{kind:?} is for borrowck, and should never appear in codegen");
|
||
}
|
||
mir::CastKind::PtrToPtr
|
||
if bx.cx().is_backend_scalar_pair(operand.layout) =>
|
||
{
|
||
if let OperandValue::Pair(data_ptr, meta) = operand.val {
|
||
if bx.cx().is_backend_scalar_pair(cast) {
|
||
OperandValue::Pair(data_ptr, meta)
|
||
} else {
|
||
// Cast of wide-ptr to thin-ptr is an extraction of data-ptr.
|
||
OperandValue::Immediate(data_ptr)
|
||
}
|
||
} else {
|
||
bug!("unexpected non-pair operand");
|
||
}
|
||
}
|
||
| mir::CastKind::IntToInt
|
||
| mir::CastKind::FloatToInt
|
||
| mir::CastKind::FloatToFloat
|
||
| mir::CastKind::IntToFloat
|
||
| mir::CastKind::PtrToPtr
|
||
| mir::CastKind::FnPtrToPtr
|
||
// Since int2ptr can have arbitrary integer types as input (so we have to do
|
||
// sign extension and all that), it is currently best handled in the same code
|
||
// path as the other integer-to-X casts.
|
||
| mir::CastKind::PointerWithExposedProvenance => {
|
||
let imm = operand.immediate();
|
||
let abi::BackendRepr::Scalar(from_scalar) = operand.layout.backend_repr else {
|
||
bug!("Found non-scalar for operand {operand:?}");
|
||
};
|
||
let from_backend_ty = bx.cx().immediate_backend_type(operand.layout);
|
||
|
||
assert!(bx.cx().is_backend_immediate(cast));
|
||
let to_backend_ty = bx.cx().immediate_backend_type(cast);
|
||
if operand.layout.is_uninhabited() {
|
||
let val = OperandValue::Immediate(bx.cx().const_poison(to_backend_ty));
|
||
return OperandRef { val, layout: cast, move_annotation: None };
|
||
}
|
||
let abi::BackendRepr::Scalar(to_scalar) = cast.layout.backend_repr else {
|
||
bug!("Found non-scalar for cast {cast:?}");
|
||
};
|
||
|
||
self.cast_immediate(bx, imm, from_scalar, from_backend_ty, to_scalar, to_backend_ty)
|
||
.map(OperandValue::Immediate)
|
||
.unwrap_or_else(|| {
|
||
bug!("Unsupported cast of {operand:?} to {cast:?}");
|
||
})
|
||
}
|
||
mir::CastKind::Transmute | mir::CastKind::Subtype => {
|
||
self.codegen_transmute_operand(bx, operand, cast)
|
||
}
|
||
};
|
||
OperandRef { val, layout: cast, move_annotation: None }
|
||
}
|
||
|
||
mir::Rvalue::Ref(_, bk, place) => {
|
||
let mk_ref = move |tcx: TyCtxt<'tcx>, ty: Ty<'tcx>| {
|
||
Ty::new_ref(tcx, tcx.lifetimes.re_erased, ty, bk.to_mutbl_lossy())
|
||
};
|
||
self.codegen_place_to_pointer(bx, place, mk_ref)
|
||
}
|
||
|
||
mir::Rvalue::RawPtr(kind, place) => {
|
||
let mk_ptr = move |tcx: TyCtxt<'tcx>, ty: Ty<'tcx>| {
|
||
Ty::new_ptr(tcx, ty, kind.to_mutbl_lossy())
|
||
};
|
||
self.codegen_place_to_pointer(bx, place, mk_ptr)
|
||
}
|
||
|
||
mir::Rvalue::BinaryOp(op_with_overflow, box (ref lhs, ref rhs))
|
||
if let Some(op) = op_with_overflow.overflowing_to_wrapping() =>
|
||
{
|
||
let lhs = self.codegen_operand(bx, lhs);
|
||
let rhs = self.codegen_operand(bx, rhs);
|
||
let result = self.codegen_scalar_checked_binop(
|
||
bx,
|
||
op,
|
||
lhs.immediate(),
|
||
rhs.immediate(),
|
||
lhs.layout.ty,
|
||
);
|
||
let val_ty = op.ty(bx.tcx(), lhs.layout.ty, rhs.layout.ty);
|
||
let operand_ty = Ty::new_tup(bx.tcx(), &[val_ty, bx.tcx().types.bool]);
|
||
OperandRef {
|
||
val: result,
|
||
layout: bx.cx().layout_of(operand_ty),
|
||
move_annotation: None,
|
||
}
|
||
}
|
||
mir::Rvalue::BinaryOp(op, box (ref lhs, ref rhs)) => {
|
||
let lhs = self.codegen_operand(bx, lhs);
|
||
let rhs = self.codegen_operand(bx, rhs);
|
||
let llresult = match (lhs.val, rhs.val) {
|
||
(
|
||
OperandValue::Pair(lhs_addr, lhs_extra),
|
||
OperandValue::Pair(rhs_addr, rhs_extra),
|
||
) => self.codegen_wide_ptr_binop(
|
||
bx,
|
||
op,
|
||
lhs_addr,
|
||
lhs_extra,
|
||
rhs_addr,
|
||
rhs_extra,
|
||
lhs.layout.ty,
|
||
),
|
||
|
||
(OperandValue::Immediate(lhs_val), OperandValue::Immediate(rhs_val)) => self
|
||
.codegen_scalar_binop(
|
||
bx,
|
||
op,
|
||
lhs_val,
|
||
rhs_val,
|
||
lhs.layout.ty,
|
||
rhs.layout.ty,
|
||
),
|
||
|
||
_ => bug!(),
|
||
};
|
||
OperandRef {
|
||
val: OperandValue::Immediate(llresult),
|
||
layout: bx.cx().layout_of(op.ty(bx.tcx(), lhs.layout.ty, rhs.layout.ty)),
|
||
move_annotation: None,
|
||
}
|
||
}
|
||
|
||
mir::Rvalue::UnaryOp(op, ref operand) => {
|
||
let operand = self.codegen_operand(bx, operand);
|
||
let is_float = operand.layout.ty.is_floating_point();
|
||
let (val, layout) = match op {
|
||
mir::UnOp::Not => {
|
||
let llval = bx.not(operand.immediate());
|
||
(OperandValue::Immediate(llval), operand.layout)
|
||
}
|
||
mir::UnOp::Neg => {
|
||
let llval = if is_float {
|
||
bx.fneg(operand.immediate())
|
||
} else {
|
||
bx.neg(operand.immediate())
|
||
};
|
||
(OperandValue::Immediate(llval), operand.layout)
|
||
}
|
||
mir::UnOp::PtrMetadata => {
|
||
assert!(operand.layout.ty.is_raw_ptr() || operand.layout.ty.is_ref(),);
|
||
let (_, meta) = operand.val.pointer_parts();
|
||
assert_eq!(operand.layout.fields.count() > 1, meta.is_some());
|
||
if let Some(meta) = meta {
|
||
(OperandValue::Immediate(meta), operand.layout.field(self.cx, 1))
|
||
} else {
|
||
(OperandValue::ZeroSized, bx.cx().layout_of(bx.tcx().types.unit))
|
||
}
|
||
}
|
||
};
|
||
assert!(
|
||
val.is_expected_variant_for_type(self.cx, layout),
|
||
"Made wrong variant {val:?} for type {layout:?}",
|
||
);
|
||
OperandRef { val, layout, move_annotation: None }
|
||
}
|
||
|
||
mir::Rvalue::Discriminant(ref place) => {
|
||
let discr_ty = rvalue.ty(self.mir, bx.tcx());
|
||
let discr_ty = self.monomorphize(discr_ty);
|
||
let operand = self.codegen_consume(bx, place.as_ref());
|
||
let discr = operand.codegen_get_discr(self, bx, discr_ty);
|
||
OperandRef {
|
||
val: OperandValue::Immediate(discr),
|
||
layout: self.cx.layout_of(discr_ty),
|
||
move_annotation: None,
|
||
}
|
||
}
|
||
|
||
mir::Rvalue::ThreadLocalRef(def_id) => {
|
||
assert!(bx.cx().tcx().is_static(def_id));
|
||
let layout = bx.layout_of(bx.cx().tcx().static_ptr_ty(def_id, bx.typing_env()));
|
||
let static_ = if !def_id.is_local() && bx.cx().tcx().needs_thread_local_shim(def_id)
|
||
{
|
||
let instance = ty::Instance {
|
||
def: ty::InstanceKind::ThreadLocalShim(def_id),
|
||
args: ty::GenericArgs::empty(),
|
||
};
|
||
let fn_ptr = bx.get_fn_addr(instance);
|
||
let fn_abi = bx.fn_abi_of_instance(instance, ty::List::empty());
|
||
let fn_ty = bx.fn_decl_backend_type(fn_abi);
|
||
let fn_attrs = if bx.tcx().def_kind(instance.def_id()).has_codegen_attrs() {
|
||
Some(bx.tcx().codegen_instance_attrs(instance.def))
|
||
} else {
|
||
None
|
||
};
|
||
bx.call(
|
||
fn_ty,
|
||
fn_attrs.as_deref(),
|
||
Some(fn_abi),
|
||
fn_ptr,
|
||
&[],
|
||
None,
|
||
Some(instance),
|
||
)
|
||
} else {
|
||
bx.get_static(def_id)
|
||
};
|
||
OperandRef { val: OperandValue::Immediate(static_), layout, move_annotation: None }
|
||
}
|
||
mir::Rvalue::Use(ref operand) => self.codegen_operand(bx, operand),
|
||
mir::Rvalue::Repeat(ref elem, len_const) => {
|
||
// All arrays have `BackendRepr::Memory`, so only the ZST cases
|
||
// end up here. Anything else forces the destination local to be
|
||
// `Memory`, and thus ends up handled in `codegen_rvalue` instead.
|
||
let operand = self.codegen_operand(bx, elem);
|
||
let array_ty = Ty::new_array_with_const_len(bx.tcx(), operand.layout.ty, len_const);
|
||
let array_ty = self.monomorphize(array_ty);
|
||
let array_layout = bx.layout_of(array_ty);
|
||
assert!(array_layout.is_zst());
|
||
OperandRef {
|
||
val: OperandValue::ZeroSized,
|
||
layout: array_layout,
|
||
move_annotation: None,
|
||
}
|
||
}
|
||
mir::Rvalue::Aggregate(ref kind, ref fields) => {
|
||
let (variant_index, active_field_index) = match **kind {
|
||
mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => {
|
||
(variant_index, active_field_index)
|
||
}
|
||
_ => (FIRST_VARIANT, None),
|
||
};
|
||
|
||
let ty = rvalue.ty(self.mir, self.cx.tcx());
|
||
let ty = self.monomorphize(ty);
|
||
let layout = self.cx.layout_of(ty);
|
||
|
||
let mut builder = OperandRefBuilder::new(layout);
|
||
for (field_idx, field) in fields.iter_enumerated() {
|
||
let op = self.codegen_operand(bx, field);
|
||
let fi = active_field_index.unwrap_or(field_idx);
|
||
builder.insert_field(bx, variant_index, fi, op);
|
||
}
|
||
|
||
let tag_result = codegen_tag_value(self.cx, variant_index, layout);
|
||
match tag_result {
|
||
Err(super::place::UninhabitedVariantError) => {
|
||
// Like codegen_set_discr we use a sound abort, but could
|
||
// potentially `unreachable` or just return the poison for
|
||
// more optimizability, if that turns out to be helpful.
|
||
bx.abort();
|
||
let val = OperandValue::poison(bx, layout);
|
||
OperandRef { val, layout, move_annotation: None }
|
||
}
|
||
Ok(maybe_tag_value) => {
|
||
if let Some((tag_field, tag_imm)) = maybe_tag_value {
|
||
builder.insert_imm(tag_field, tag_imm);
|
||
}
|
||
builder.build(bx.cx())
|
||
}
|
||
}
|
||
}
|
||
mir::Rvalue::WrapUnsafeBinder(ref operand, binder_ty) => {
|
||
let operand = self.codegen_operand(bx, operand);
|
||
let binder_ty = self.monomorphize(binder_ty);
|
||
let layout = bx.cx().layout_of(binder_ty);
|
||
OperandRef { val: operand.val, layout, move_annotation: None }
|
||
}
|
||
mir::Rvalue::CopyForDeref(_) => bug!("`CopyForDeref` in codegen"),
|
||
}
|
||
}
|
||
|
||
/// Codegen an `Rvalue::RawPtr` or `Rvalue::Ref`
|
||
fn codegen_place_to_pointer(
|
||
&mut self,
|
||
bx: &mut Bx,
|
||
place: mir::Place<'tcx>,
|
||
mk_ptr_ty: impl FnOnce(TyCtxt<'tcx>, Ty<'tcx>) -> Ty<'tcx>,
|
||
) -> OperandRef<'tcx, Bx::Value> {
|
||
let cg_place = self.codegen_place(bx, place.as_ref());
|
||
let val = cg_place.val.address();
|
||
|
||
let ty = cg_place.layout.ty;
|
||
assert!(
|
||
if bx.cx().tcx().type_has_metadata(ty, bx.cx().typing_env()) {
|
||
matches!(val, OperandValue::Pair(..))
|
||
} else {
|
||
matches!(val, OperandValue::Immediate(..))
|
||
},
|
||
"Address of place was unexpectedly {val:?} for pointee type {ty:?}",
|
||
);
|
||
|
||
OperandRef {
|
||
val,
|
||
layout: self.cx.layout_of(mk_ptr_ty(self.cx.tcx(), ty)),
|
||
move_annotation: None,
|
||
}
|
||
}
|
||
|
||
fn codegen_scalar_binop(
|
||
&mut self,
|
||
bx: &mut Bx,
|
||
op: mir::BinOp,
|
||
lhs: Bx::Value,
|
||
rhs: Bx::Value,
|
||
lhs_ty: Ty<'tcx>,
|
||
rhs_ty: Ty<'tcx>,
|
||
) -> Bx::Value {
|
||
let is_float = lhs_ty.is_floating_point();
|
||
let is_signed = lhs_ty.is_signed();
|
||
match op {
|
||
mir::BinOp::Add => {
|
||
if is_float {
|
||
bx.fadd(lhs, rhs)
|
||
} else {
|
||
bx.add(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::AddUnchecked => {
|
||
if is_signed {
|
||
bx.unchecked_sadd(lhs, rhs)
|
||
} else {
|
||
bx.unchecked_uadd(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::Sub => {
|
||
if is_float {
|
||
bx.fsub(lhs, rhs)
|
||
} else {
|
||
bx.sub(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::SubUnchecked => {
|
||
if is_signed {
|
||
bx.unchecked_ssub(lhs, rhs)
|
||
} else {
|
||
bx.unchecked_usub(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::Mul => {
|
||
if is_float {
|
||
bx.fmul(lhs, rhs)
|
||
} else {
|
||
bx.mul(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::MulUnchecked => {
|
||
if is_signed {
|
||
bx.unchecked_smul(lhs, rhs)
|
||
} else {
|
||
bx.unchecked_umul(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::Div => {
|
||
if is_float {
|
||
bx.fdiv(lhs, rhs)
|
||
} else if is_signed {
|
||
bx.sdiv(lhs, rhs)
|
||
} else {
|
||
bx.udiv(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::Rem => {
|
||
if is_float {
|
||
bx.frem(lhs, rhs)
|
||
} else if is_signed {
|
||
bx.srem(lhs, rhs)
|
||
} else {
|
||
bx.urem(lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::BitOr => bx.or(lhs, rhs),
|
||
mir::BinOp::BitAnd => bx.and(lhs, rhs),
|
||
mir::BinOp::BitXor => bx.xor(lhs, rhs),
|
||
mir::BinOp::Offset => {
|
||
let pointee_type = lhs_ty
|
||
.builtin_deref(true)
|
||
.unwrap_or_else(|| bug!("deref of non-pointer {:?}", lhs_ty));
|
||
let pointee_layout = bx.cx().layout_of(pointee_type);
|
||
if pointee_layout.is_zst() {
|
||
// `Offset` works in terms of the size of pointee,
|
||
// so offsetting a pointer to ZST is a noop.
|
||
lhs
|
||
} else {
|
||
let llty = bx.cx().backend_type(pointee_layout);
|
||
if !rhs_ty.is_signed() {
|
||
bx.inbounds_nuw_gep(llty, lhs, &[rhs])
|
||
} else {
|
||
bx.inbounds_gep(llty, lhs, &[rhs])
|
||
}
|
||
}
|
||
}
|
||
mir::BinOp::Shl | mir::BinOp::ShlUnchecked => {
|
||
let rhs = base::build_shift_expr_rhs(bx, lhs, rhs, op == mir::BinOp::ShlUnchecked);
|
||
bx.shl(lhs, rhs)
|
||
}
|
||
mir::BinOp::Shr | mir::BinOp::ShrUnchecked => {
|
||
let rhs = base::build_shift_expr_rhs(bx, lhs, rhs, op == mir::BinOp::ShrUnchecked);
|
||
if is_signed { bx.ashr(lhs, rhs) } else { bx.lshr(lhs, rhs) }
|
||
}
|
||
mir::BinOp::Ne
|
||
| mir::BinOp::Lt
|
||
| mir::BinOp::Gt
|
||
| mir::BinOp::Eq
|
||
| mir::BinOp::Le
|
||
| mir::BinOp::Ge => {
|
||
if is_float {
|
||
bx.fcmp(base::bin_op_to_fcmp_predicate(op), lhs, rhs)
|
||
} else {
|
||
bx.icmp(base::bin_op_to_icmp_predicate(op, is_signed), lhs, rhs)
|
||
}
|
||
}
|
||
mir::BinOp::Cmp => {
|
||
assert!(!is_float);
|
||
bx.three_way_compare(lhs_ty, lhs, rhs)
|
||
}
|
||
mir::BinOp::AddWithOverflow
|
||
| mir::BinOp::SubWithOverflow
|
||
| mir::BinOp::MulWithOverflow => {
|
||
bug!("{op:?} needs to return a pair, so call codegen_scalar_checked_binop instead")
|
||
}
|
||
}
|
||
}
|
||
|
||
fn codegen_wide_ptr_binop(
|
||
&mut self,
|
||
bx: &mut Bx,
|
||
op: mir::BinOp,
|
||
lhs_addr: Bx::Value,
|
||
lhs_extra: Bx::Value,
|
||
rhs_addr: Bx::Value,
|
||
rhs_extra: Bx::Value,
|
||
_input_ty: Ty<'tcx>,
|
||
) -> Bx::Value {
|
||
match op {
|
||
mir::BinOp::Eq => {
|
||
let lhs = bx.icmp(IntPredicate::IntEQ, lhs_addr, rhs_addr);
|
||
let rhs = bx.icmp(IntPredicate::IntEQ, lhs_extra, rhs_extra);
|
||
bx.and(lhs, rhs)
|
||
}
|
||
mir::BinOp::Ne => {
|
||
let lhs = bx.icmp(IntPredicate::IntNE, lhs_addr, rhs_addr);
|
||
let rhs = bx.icmp(IntPredicate::IntNE, lhs_extra, rhs_extra);
|
||
bx.or(lhs, rhs)
|
||
}
|
||
mir::BinOp::Le | mir::BinOp::Lt | mir::BinOp::Ge | mir::BinOp::Gt => {
|
||
// a OP b ~ a.0 STRICT(OP) b.0 | (a.0 == b.0 && a.1 OP a.1)
|
||
let (op, strict_op) = match op {
|
||
mir::BinOp::Lt => (IntPredicate::IntULT, IntPredicate::IntULT),
|
||
mir::BinOp::Le => (IntPredicate::IntULE, IntPredicate::IntULT),
|
||
mir::BinOp::Gt => (IntPredicate::IntUGT, IntPredicate::IntUGT),
|
||
mir::BinOp::Ge => (IntPredicate::IntUGE, IntPredicate::IntUGT),
|
||
_ => bug!(),
|
||
};
|
||
let lhs = bx.icmp(strict_op, lhs_addr, rhs_addr);
|
||
let and_lhs = bx.icmp(IntPredicate::IntEQ, lhs_addr, rhs_addr);
|
||
let and_rhs = bx.icmp(op, lhs_extra, rhs_extra);
|
||
let rhs = bx.and(and_lhs, and_rhs);
|
||
bx.or(lhs, rhs)
|
||
}
|
||
_ => {
|
||
bug!("unexpected wide ptr binop");
|
||
}
|
||
}
|
||
}
|
||
|
||
fn codegen_scalar_checked_binop(
|
||
&mut self,
|
||
bx: &mut Bx,
|
||
op: mir::BinOp,
|
||
lhs: Bx::Value,
|
||
rhs: Bx::Value,
|
||
input_ty: Ty<'tcx>,
|
||
) -> OperandValue<Bx::Value> {
|
||
let (val, of) = match op {
|
||
// These are checked using intrinsics
|
||
mir::BinOp::Add | mir::BinOp::Sub | mir::BinOp::Mul => {
|
||
let oop = match op {
|
||
mir::BinOp::Add => OverflowOp::Add,
|
||
mir::BinOp::Sub => OverflowOp::Sub,
|
||
mir::BinOp::Mul => OverflowOp::Mul,
|
||
_ => unreachable!(),
|
||
};
|
||
bx.checked_binop(oop, input_ty, lhs, rhs)
|
||
}
|
||
_ => bug!("Operator `{:?}` is not a checkable operator", op),
|
||
};
|
||
|
||
OperandValue::Pair(val, of)
|
||
}
|
||
}
|
||
|
||
/// Transmutes a single scalar value `imm` from `from_scalar` to `to_scalar`.
|
||
///
|
||
/// This is expected to be in *immediate* form, as seen in [`OperandValue::Immediate`]
|
||
/// or [`OperandValue::Pair`] (so `i1` for bools, not `i8`, for example).
|
||
///
|
||
/// ICEs if the passed-in `imm` is not a value of the expected type for
|
||
/// `from_scalar`, such as if it's a vector or a pair.
|
||
pub(super) fn transmute_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
|
||
bx: &mut Bx,
|
||
mut imm: Bx::Value,
|
||
from_scalar: abi::Scalar,
|
||
to_scalar: abi::Scalar,
|
||
) -> Bx::Value {
|
||
assert_eq!(from_scalar.size(bx.cx()), to_scalar.size(bx.cx()));
|
||
let imm_ty = bx.cx().val_ty(imm);
|
||
assert_ne!(
|
||
bx.cx().type_kind(imm_ty),
|
||
TypeKind::Vector,
|
||
"Vector type {imm_ty:?} not allowed in transmute_scalar {from_scalar:?} -> {to_scalar:?}"
|
||
);
|
||
|
||
// While optimizations will remove no-op transmutes, they might still be
|
||
// there in debug or things that aren't no-op in MIR because they change
|
||
// the Rust type but not the underlying layout/niche.
|
||
if from_scalar == to_scalar {
|
||
return imm;
|
||
}
|
||
|
||
use abi::Primitive::*;
|
||
imm = bx.from_immediate(imm);
|
||
|
||
let from_backend_ty = bx.cx().type_from_scalar(from_scalar);
|
||
debug_assert_eq!(bx.cx().val_ty(imm), from_backend_ty);
|
||
let to_backend_ty = bx.cx().type_from_scalar(to_scalar);
|
||
|
||
// If we have a scalar, we must already know its range. Either
|
||
//
|
||
// 1) It's a parameter with `range` parameter metadata,
|
||
// 2) It's something we `load`ed with `!range` metadata, or
|
||
// 3) After a transmute we `assume`d the range (see below).
|
||
//
|
||
// That said, last time we tried removing this, it didn't actually help
|
||
// the rustc-perf results, so might as well keep doing it
|
||
// <https://github.com/rust-lang/rust/pull/135610#issuecomment-2599275182>
|
||
assume_scalar_range(bx, imm, from_scalar, from_backend_ty, Some(&to_scalar));
|
||
|
||
imm = match (from_scalar.primitive(), to_scalar.primitive()) {
|
||
(Int(..) | Float(_), Int(..) | Float(_)) => bx.bitcast(imm, to_backend_ty),
|
||
(Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty),
|
||
(Int(..), Pointer(..)) => bx.inttoptr(imm, to_backend_ty),
|
||
(Pointer(..), Int(..)) => {
|
||
// FIXME: this exposes the provenance, which shouldn't be necessary.
|
||
bx.ptrtoint(imm, to_backend_ty)
|
||
}
|
||
(Float(_), Pointer(..)) => {
|
||
let int_imm = bx.bitcast(imm, bx.cx().type_isize());
|
||
bx.inttoptr(int_imm, to_backend_ty)
|
||
}
|
||
(Pointer(..), Float(_)) => {
|
||
// FIXME: this exposes the provenance, which shouldn't be necessary.
|
||
let int_imm = bx.ptrtoint(imm, bx.cx().type_isize());
|
||
bx.bitcast(int_imm, to_backend_ty)
|
||
}
|
||
};
|
||
|
||
debug_assert_eq!(bx.cx().val_ty(imm), to_backend_ty);
|
||
|
||
// This `assume` remains important for cases like (a conceptual)
|
||
// transmute::<u32, NonZeroU32>(x) == 0
|
||
// since it's never passed to something with parameter metadata (especially
|
||
// after MIR inlining) so the only way to tell the backend about the
|
||
// constraint that the `transmute` introduced is to `assume` it.
|
||
assume_scalar_range(bx, imm, to_scalar, to_backend_ty, Some(&from_scalar));
|
||
|
||
imm = bx.to_immediate_scalar(imm, to_scalar);
|
||
imm
|
||
}
|
||
|
||
/// Emits an `assume` call that `imm`'s value is within the known range of `scalar`.
|
||
///
|
||
/// If `known` is `Some`, only emits the assume if it's more specific than
|
||
/// whatever is already known from the range of *that* scalar.
|
||
fn assume_scalar_range<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
|
||
bx: &mut Bx,
|
||
imm: Bx::Value,
|
||
scalar: abi::Scalar,
|
||
backend_ty: Bx::Type,
|
||
known: Option<&abi::Scalar>,
|
||
) {
|
||
if matches!(bx.cx().sess().opts.optimize, OptLevel::No) {
|
||
return;
|
||
}
|
||
|
||
match (scalar, known) {
|
||
(abi::Scalar::Union { .. }, _) => return,
|
||
(_, None) => {
|
||
if scalar.is_always_valid(bx.cx()) {
|
||
return;
|
||
}
|
||
}
|
||
(abi::Scalar::Initialized { valid_range, .. }, Some(known)) => {
|
||
let known_range = known.valid_range(bx.cx());
|
||
if valid_range.contains_range(known_range, scalar.size(bx.cx())) {
|
||
return;
|
||
}
|
||
}
|
||
}
|
||
|
||
match scalar.primitive() {
|
||
abi::Primitive::Int(..) => {
|
||
let range = scalar.valid_range(bx.cx());
|
||
bx.assume_integer_range(imm, backend_ty, range);
|
||
}
|
||
abi::Primitive::Pointer(abi::AddressSpace::ZERO)
|
||
if !scalar.valid_range(bx.cx()).contains(0) =>
|
||
{
|
||
bx.assume_nonnull(imm);
|
||
}
|
||
abi::Primitive::Pointer(..) | abi::Primitive::Float(..) => {}
|
||
}
|
||
}
|