Simplify the back-end of InstBuilder.
We don't want to distinguish between single-result and multiple-result instructions any longer. - Merge the simple_instruction() and complex_instruction() builder methods into a single build() that can handle all cases. - All format constructors now take a ctrl_type argument. Previously, some would take a result_type argument. - Instruction constructors no longer attempt to compute a single result type. Just pass a ctrl_type and let the backend decide. Fix one format constructor call in legalizer/split.rs which now takes a ctrl_type instead of a result type.
This commit is contained in:
Jakob Stoklund Olesen
@@ -24,21 +24,11 @@ pub trait InstBuilderBase<'f>: Sized {
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fn data_flow_graph(&self) -> &DataFlowGraph;
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fn data_flow_graph_mut(&mut self) -> &mut DataFlowGraph;
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/// Insert a simple instruction and return a reference to it.
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/// Insert an instruction and return a reference to it, consuming the builder.
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///
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/// A 'simple' instruction has at most one result, and the `data.ty` field must contain the
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/// result type or `VOID` for an instruction with no result values.
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fn simple_instruction(self, data: InstructionData) -> (Inst, &'f mut DataFlowGraph);
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/// Insert a simple instruction and return a reference to it.
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///
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/// A 'complex' instruction may produce multiple results, and the result types may depend on a
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/// controlling type variable. For non-polymorphic instructions with multiple results, pass
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/// `VOID` for the `ctrl_typevar` argument.
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fn complex_instruction(self,
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data: InstructionData,
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ctrl_typevar: Type)
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-> (Inst, &'f mut DataFlowGraph);
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/// The result types may depend on a controlling type variable. For non-polymorphic
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/// instructions with multiple results, pass `VOID` for the `ctrl_typevar` argument.
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fn build(self, data: InstructionData, ctrl_typevar: Type) -> (Inst, &'f mut DataFlowGraph);
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}
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// Include trait code generated by `lib/cretonne/meta/gen_instr.py`.
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@@ -79,16 +69,7 @@ impl<'c, 'fc, 'fd> InstBuilderBase<'fd> for InsertBuilder<'c, 'fc, 'fd> {
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self.dfg
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}
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fn simple_instruction(self, data: InstructionData) -> (Inst, &'fd mut DataFlowGraph) {
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let inst = self.dfg.make_inst(data);
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self.pos.insert_inst(inst);
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(inst, self.dfg)
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}
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fn complex_instruction(self,
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data: InstructionData,
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ctrl_typevar: Type)
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-> (Inst, &'fd mut DataFlowGraph) {
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fn build(self, data: InstructionData, ctrl_typevar: Type) -> (Inst, &'fd mut DataFlowGraph) {
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let inst = self.dfg.make_inst(data);
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self.dfg.make_inst_results(inst, ctrl_typevar);
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self.pos.insert_inst(inst);
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@@ -98,20 +79,12 @@ impl<'c, 'fc, 'fd> InstBuilderBase<'fd> for InsertBuilder<'c, 'fc, 'fd> {
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/// Instruction builder that replaces an existing instruction.
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///
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/// The inserted instruction will have the same `Inst` number as the old one. This is the only way
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/// of rewriting the first result value of an instruction since this is a `ExpandedValue::Direct`
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/// variant which encodes the instruction number directly.
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/// The inserted instruction will have the same `Inst` number as the old one.
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///
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/// If the old instruction produced a value, the same value number will refer to the new
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/// instruction's first result, so if that value has any uses the type should stay the same.
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///
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/// If the old instruction still has secondary result values attached, it is assumed that the new
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/// instruction produces the same number and types of results. The old secondary values are
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/// preserved. If the replacement instruction format does not support multiple results, the builder
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/// panics. It is a bug to leave result values dangling.
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///
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/// If the old instruction was capable of producing secondary results, but the values have been
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/// detached, new result values are generated by calling `DataFlowGraph::make_inst_results()`.
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/// If the old instruction still has result values attached, it is assumed that the new instruction
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/// produces the same number and types of results. The old result values are preserved. If the
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/// replacement instruction format does not support multiple results, the builder panics. It is a
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/// bug to leave result values dangling.
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pub struct ReplaceBuilder<'f> {
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dfg: &'f mut DataFlowGraph,
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inst: Inst,
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@@ -136,46 +109,20 @@ impl<'f> InstBuilderBase<'f> for ReplaceBuilder<'f> {
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self.dfg
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}
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fn simple_instruction(self, data: InstructionData) -> (Inst, &'f mut DataFlowGraph) {
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// The replacement instruction cannot generate multiple results, so verify that the old
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// instruction's secondary results have been detached.
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let old_second_value = self.dfg[self.inst].second_result();
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assert_eq!(old_second_value,
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None,
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"Secondary result values {:?} would be left dangling by replacing {} with {}",
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self.dfg.inst_results(self.inst),
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self.dfg[self.inst].opcode(),
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data.opcode());
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// Splat the new instruction on top of the old one.
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self.dfg[self.inst] = data;
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(self.inst, self.dfg)
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}
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fn complex_instruction(self,
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data: InstructionData,
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ctrl_typevar: Type)
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-> (Inst, &'f mut DataFlowGraph) {
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// If the old instruction still has secondary results attached, we'll keep them.
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let old_second_value = self.dfg[self.inst].second_result();
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fn build(self, data: InstructionData, ctrl_typevar: Type) -> (Inst, &'f mut DataFlowGraph) {
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// Splat the new instruction on top of the old one.
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self.dfg[self.inst] = data;
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if old_second_value.is_none() {
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// The old secondary values were either detached or non-existent.
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// Construct new ones and set the first result type too.
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if !self.dfg.has_results(self.inst) {
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// The old result values were either detached or non-existent.
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// Construct new ones.
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self.dfg.make_inst_results(self.inst, ctrl_typevar);
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} else {
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// Reattach the old secondary values.
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let old_second_value = self.dfg.inst_results(self.inst).get(1).cloned();
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if let Some(val_ref) = self.dfg[self.inst].second_result_mut() {
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// Don't check types here. Leave that to the verifier.
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*val_ref = old_second_value.into();
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} else {
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// Actually, this instruction format should have called `simple_instruction()`, but
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// we don't have a rule against calling `complex_instruction()` even when it is
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// overkill.
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panic!("Secondary result values left dangling");
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}
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// Normally, make_inst_results() would also set the first result type, but we're not
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@@ -633,7 +633,12 @@ impl DataFlowGraph {
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.expect("Instruction has no results")
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}
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/// Iterate through all the results of an instruction.
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/// Test if `inst` has any result values currently.
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pub fn has_results(&self, inst: Inst) -> bool {
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!self.results[inst].is_empty()
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}
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/// Return all the results of an instruction.
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pub fn inst_results(&self, inst: Inst) -> &[Value] {
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self.results[inst].as_slice(&self.value_lists)
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}
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@@ -228,7 +228,7 @@ fn split_value(dfg: &mut DataFlowGraph,
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// need to insert a split instruction before returning.
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pos.goto_top(ebb);
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pos.next_inst();
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let concat_inst = dfg.ins(pos).Binary(concat, ty, lo, hi).0;
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let concat_inst = dfg.ins(pos).Binary(concat, split_type, lo, hi).0;
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let concat_val = dfg.first_result(concat_inst);
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dfg.change_to_alias(value, concat_val);
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