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Simplify const propagator by removing unused code paths

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Oliver Schneider 2018-01-30 14:28:45 +01:00
parent 411fcf58fd
commit 1561b4ad50
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GPG key ID: A69F8D225B3AD7D9
1 changed files with 52 additions and 71 deletions
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123
src/librustc_mir/transform/const_prop.rs
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@ -359,81 +359,62 @@ impl<'b, 'a, 'tcx> Visitor<'tcx> for ConstPropagator<'b, 'a, 'tcx> {
&mut self, &mut self,
block: BasicBlock, block: BasicBlock,
kind: &TerminatorKind<'tcx>, kind: &TerminatorKind<'tcx>,
_location: Location, location: Location,
) { ) {
match kind { self.super_terminator_kind(block, kind, location);
TerminatorKind::SwitchInt { discr: value, .. } | if let TerminatorKind::Assert { expected, msg, cond, .. } = kind {
TerminatorKind::Yield { value, .. } | if let Some(value) = self.eval_operand(cond) {
TerminatorKind::Assert { cond: value, .. } => { if Value::ByVal(PrimVal::from_bool(*expected)) != value.0 {
match value { let span = self.mir[block]
Operand::Constant(box Constant { .terminator
literal: Literal::Value { .as_ref()
value: &ty::Const { .unwrap()
val: ConstVal::Value(_), .source_info
.. .span;
}, let node_id = self
}, .tcx
.. .hir
}) => return, .as_local_node_id(self.source.def_id)
_ => {}, .expect("some part of a failing const eval must be local");
} let mut lint = self.tcx.struct_span_lint_node(
if let Some(value) = self.eval_operand(value) { ::rustc::lint::builtin::CONST_ERR,
if let TerminatorKind::Assert { expected, msg, .. } = kind { node_id,
if Value::ByVal(PrimVal::from_bool(*expected)) != value.0 { span,
let span = self.mir[block] "constant evaluation error",
.terminator );
.as_ref() use rustc::mir::AssertMessage::*;
.unwrap() match msg {
.source_info GeneratorResumedAfterReturn =>
.span; lint.span_label(span, "generator resumed after completion"),
let node_id = self GeneratorResumedAfterPanic =>
.tcx lint.span_label(span, "generator resumed after panicking"),
.hir Math(ref err) => lint.span_label(span, err.description()),
.as_local_node_id(self.source.def_id) BoundsCheck { ref len, ref index } => {
.expect("some part of a failing const eval must be local"); let len = self.eval_operand(len).expect("len must be const");
let mut lint = self.tcx.struct_span_lint_node( let len = match len.0 {
::rustc::lint::builtin::CONST_ERR, Value::ByVal(PrimVal::Bytes(n)) => n,
node_id, _ => bug!("const len not primitive: {:?}", len),
};
let index = self
.eval_operand(index)
.expect("index must be const");
let index = match index.0 {
Value::ByVal(PrimVal::Bytes(n)) => n,
_ => bug!("const index not primitive: {:?}", index),
};
lint.span_label(
span, span,
"constant evaluation error", format!(
); "index out of bounds: \
use rustc::mir::AssertMessage::*; the len is {} but the index is {}",
match msg { len,
GeneratorResumedAfterReturn => index,
lint.span_label(span, "generator resumed after completion"), ),
GeneratorResumedAfterPanic => )
lint.span_label(span, "generator resumed after panicking"), },
Math(ref err) => lint.span_label(span, err.description()), }.emit();
BoundsCheck { ref len, ref index } => {
let len = self.eval_operand(len).expect("len must be const");
let len = match len.0 {
Value::ByVal(PrimVal::Bytes(n)) => n,
_ => bug!("const len not primitive: {:?}", len),
};
let index = self
.eval_operand(index)
.expect("index must be const");
let index = match index.0 {
Value::ByVal(PrimVal::Bytes(n)) => n,
_ => bug!("const index not primitive: {:?}", index),
};
lint.span_label(
span,
format!(
"index out of bounds: \
the len is {} but the index is {}",
len,
index,
),
)
},
}.emit();
}
}
} }
} }
// FIXME: do this optimization for function calls
_ => {},
} }
} }
} }