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Refactor: Separate LocalRef variant for not-evaluated-yet operands #109582

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merged 1 commit into from
Mar 27, 2023
Merged

Refactor: Separate LocalRef variant for not-evaluated-yet operands #109582

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12 changes: 6 additions & 6 deletions compiler/rustc_codegen_ssa/src/mir/block.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -397,8 +397,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {

PassMode::Cast(cast_ty, _) => {
let op = match self.locals[mir::RETURN_PLACE] {
LocalRef::Operand(Some(op)) => op,
LocalRef::Operand(None) => bug!("use of return before def"),
LocalRef::Operand(op) => op,
LocalRef::PendingOperand => bug!("use of return before def"),
LocalRef::Place(cg_place) => OperandRef {
val: Ref(cg_place.llval, None, cg_place.align),
layout: cg_place.layout,
Expand Down Expand Up @@ -1673,7 +1673,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
match self.locals[index] {
LocalRef::Place(dest) => dest,
LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
LocalRef::Operand(None) => {
LocalRef::PendingOperand => {
// Handle temporary places, specifically `Operand` ones, as
// they don't have `alloca`s.
return if fn_ret.is_indirect() {
Expand All @@ -1694,7 +1694,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
ReturnDest::DirectOperand(index)
};
}
LocalRef::Operand(Some(_)) => {
LocalRef::Operand(_) => {
bug!("place local already assigned to");
}
}
Expand Down Expand Up @@ -1737,7 +1737,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
IndirectOperand(tmp, index) => {
let op = bx.load_operand(tmp);
tmp.storage_dead(bx);
self.locals[index] = LocalRef::Operand(Some(op));
self.locals[index] = LocalRef::Operand(op);
self.debug_introduce_local(bx, index);
}
DirectOperand(index) => {
Expand All @@ -1752,7 +1752,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
} else {
OperandRef::from_immediate_or_packed_pair(bx, llval, ret_abi.layout)
};
self.locals[index] = LocalRef::Operand(Some(op));
self.locals[index] = LocalRef::Operand(op);
self.debug_introduce_local(bx, index);
}
}
Expand Down
8 changes: 4 additions & 4 deletions compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -312,7 +312,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
LocalRef::Place(place) | LocalRef::UnsizedPlace(place) => {
bx.set_var_name(place.llval, name);
}
LocalRef::Operand(Some(operand)) => match operand.val {
LocalRef::Operand(operand) => match operand.val {
OperandValue::Ref(x, ..) | OperandValue::Immediate(x) => {
bx.set_var_name(x, name);
}
Expand All @@ -323,7 +323,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
bx.set_var_name(b, &(name.clone() + ".1"));
}
},
LocalRef::Operand(None) => {}
LocalRef::PendingOperand => {}
}
}

Expand All @@ -332,9 +332,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
}

let base = match local_ref {
LocalRef::Operand(None) => return,
LocalRef::PendingOperand => return,

LocalRef::Operand(Some(operand)) => {
LocalRef::Operand(operand) => {
// Don't spill operands onto the stack in naked functions.
// See: https://github.com/rust-lang/rust/issues/42779
let attrs = bx.tcx().codegen_fn_attrs(self.instance.def_id());
Expand Down
11 changes: 7 additions & 4 deletions compiler/rustc_codegen_ssa/src/mir/mod.rs
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Expand Up @@ -123,7 +123,10 @@ enum LocalRef<'tcx, V> {
/// Every time it is initialized, we have to reallocate the place
/// and update the fat pointer. That's the reason why it is indirect.
UnsizedPlace(PlaceRef<'tcx, V>),
Operand(Option<OperandRef<'tcx, V>>),
/// The backend [`OperandValue`] has already been generated.
Operand(OperandRef<'tcx, V>),
/// Will be a `Self::Operand` once we get to its definition.
PendingOperand,
}

impl<'a, 'tcx, V: CodegenObject> LocalRef<'tcx, V> {
Expand All @@ -135,9 +138,9 @@ impl<'a, 'tcx, V: CodegenObject> LocalRef<'tcx, V> {
// Zero-size temporaries aren't always initialized, which
// doesn't matter because they don't contain data, but
// we need something in the operand.
LocalRef::Operand(Some(OperandRef::new_zst(bx, layout)))
LocalRef::Operand(OperandRef::new_zst(bx, layout))
} else {
LocalRef::Operand(None)
LocalRef::PendingOperand
}
}
}
Expand Down Expand Up @@ -337,7 +340,7 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
// We don't have to cast or keep the argument in the alloca.
// FIXME(eddyb): We should figure out how to use llvm.dbg.value instead
// of putting everything in allocas just so we can use llvm.dbg.declare.
let local = |op| LocalRef::Operand(Some(op));
let local = |op| LocalRef::Operand(op);
match arg.mode {
PassMode::Ignore => {
return local(OperandRef::new_zst(bx, arg.layout));
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_codegen_ssa/src/mir/operand.rs
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Expand Up @@ -370,7 +370,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
debug!("maybe_codegen_consume_direct(place_ref={:?})", place_ref);

match self.locals[place_ref.local] {
LocalRef::Operand(Some(mut o)) => {
LocalRef::Operand(mut o) => {
// Moves out of scalar and scalar pair fields are trivial.
for elem in place_ref.projection.iter() {
match elem {
Expand All @@ -395,7 +395,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {

Some(o)
}
LocalRef::Operand(None) => {
LocalRef::PendingOperand => {
bug!("use of {:?} before def", place_ref);
}
LocalRef::Place(..) | LocalRef::UnsizedPlace(..) => {
Expand Down
3 changes: 3 additions & 0 deletions compiler/rustc_codegen_ssa/src/mir/place.rs
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Expand Up @@ -558,6 +558,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
bug!("using operand local {:?} as place", place_ref);
}
}
LocalRef::PendingOperand => {
bug!("using still-pending operand local {:?} as place", place_ref);
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@scottmcm scottmcm Mar 25, 2023 •
edited
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This is the one place that wasn't already distinguishing between Some/None, and near as I can tell that's just because the None case is impossible -- at least it seems plausible that we should never be using a not-evaluated-yet operand as a place, and I never hit an ICE from a stage2 build nor any codegen tests having added this check.

}
};
for elem in place_ref.projection[base..].iter() {
cg_base = match *elem {
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_codegen_ssa/src/mir/rvalue.rs
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Expand Up @@ -545,7 +545,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
// ZST are passed as operands and require special handling
// because codegen_place() panics if Local is operand.
if let Some(index) = place.as_local() {
if let LocalRef::Operand(Some(op)) = self.locals[index] {
if let LocalRef::Operand(op) = self.locals[index] {
if let ty::Array(_, n) = op.layout.ty.kind() {
let n = n.eval_target_usize(bx.cx().tcx(), ty::ParamEnv::reveal_all());
return bx.cx().const_usize(n);
Expand Down
6 changes: 3 additions & 3 deletions compiler/rustc_codegen_ssa/src/mir/statement.rs
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Expand Up @@ -18,12 +18,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
LocalRef::UnsizedPlace(cg_indirect_dest) => {
self.codegen_rvalue_unsized(bx, cg_indirect_dest, rvalue)
}
LocalRef::Operand(None) => {
LocalRef::PendingOperand => {
let operand = self.codegen_rvalue_operand(bx, rvalue);
self.locals[index] = LocalRef::Operand(Some(operand));
self.locals[index] = LocalRef::Operand(operand);
self.debug_introduce_local(bx, index);
}
LocalRef::Operand(Some(op)) => {
LocalRef::Operand(op) => {
if !op.layout.is_zst() {
span_bug!(
statement.source_info.span,
Expand Down