Improved SSA and added unused value checks

src/ssa/IR.go

@@ -0,0 +1,83 @@
+package ssa
+
+import (
+	"git.urbach.dev/cli/q/src/cpu"
+)
+
+// IR is a list of basic blocks.
+type IR struct {
+	Blocks []*Block
+}
+
+// AddBlock adds a new block to the function.
+func (f *IR) AddBlock() *Block {
+	block := &Block{
+		Instructions: make([]Value, 0, 8),
+	}
+
+	f.Blocks = append(f.Blocks, block)
+	return block
+}
+
+// Append adds a new value to the last block.
+func (f *IR) Append(instr Value) Value {
+	if len(f.Blocks) == 0 {
+		f.AddBlock()
+	}
+
+	if instr.IsConst() {
+		for existing := range f.Values {
+			if existing.IsConst() && instr.Equals(existing) {
+				return existing
+			}
+		}
+	}
+
+	return f.Blocks[len(f.Blocks)-1].Append(instr)
+}
+
+// AppendInt adds a new integer value to the last block.
+func (f *IR) AppendInt(x int) *Int {
+	v := &Int{Int: x}
+	f.Append(v)
+	return v
+}
+
+// AppendRegister adds a new register value to the last block.
+func (f *IR) AppendRegister(reg cpu.Register) *Register {
+	v := &Register{Register: reg}
+	f.Append(v)
+	return v
+}
+
+// AppendFunction adds a new function value to the last block.
+func (f *IR) AppendFunction(name string) *Function {
+	v := &Function{UniqueName: name}
+	f.Append(v)
+	return v
+}
+
+// AppendBytes adds a new byte slice value to the last block.
+func (f *IR) AppendBytes(s []byte) *Bytes {
+	v := &Bytes{Bytes: s}
+	f.Append(v)
+	return v
+}
+
+// AppendString adds a new string value to the last block.
+func (f *IR) AppendString(s string) *Bytes {
+	v := &Bytes{Bytes: []byte(s)}
+	f.Append(v)
+	return v
+}
+
+// Values yields on each value.
+func (f *IR) Values(yield func(Value) bool) {
+	for _, block := range f.Blocks {
+		for _, instr := range block.Instructions {
+			if !yield(instr) {
+				return
+			}
+		}
+	}
+}