Improved SSA and added unused value checks

src/ssa/Value.go

@@ -1,83 +1,13 @@
 package ssa
 
-import (
-	"fmt"
+import "git.urbach.dev/cli/q/src/token"
 
-	"git.urbach.dev/cli/q/src/cpu"
-)
-
-// Value is a single instruction in a basic block.
-// It is implemented as a "fat struct" for performance reasons.
-// It contains all the fields necessary to represent all instruction types.
-type Value struct {
-	Args     []*Value
-	Int      int
-	Text     string
-	Register cpu.Register
-	Type     Type
-}
-
-// Equals returns true if the values are equal.
-func (a Value) Equals(b Value) bool {
-	if a.Type != b.Type {
-		return false
-	}
-
-	if a.Int != b.Int {
-		return false
-	}
-
-	if a.Text != b.Text {
-		return false
-	}
-
-	if a.Register != b.Register {
-		return false
-	}
-
-	if len(a.Args) != len(b.Args) {
-		return false
-	}
-
-	for i := range a.Args {
-		if !a.Args[i].Equals(*b.Args[i]) {
-			return false
-		}
-	}
-
-	return true
-}
-
-// IsConst returns true if the value is constant.
-func (i *Value) IsConst() bool {
-	switch i.Type {
-	case Func, Int, Register, String:
-		return true
-	default:
-		return false
-	}
-}
-
-// String returns a human-readable representation of the instruction.
-func (i *Value) String() string {
-	switch i.Type {
-	case Func:
-		return i.Text
-	case Int:
-		return fmt.Sprintf("%d", i.Int)
-	case Register:
-		return i.Register.String()
-	case String:
-		return fmt.Sprintf("\"%s\"", i.Text)
-	case Add:
-		return fmt.Sprintf("%s + %s", i.Args[0], i.Args[1])
-	case Return:
-		return fmt.Sprintf("return %s", i.Args[0])
-	case Call:
-		return fmt.Sprintf("call%v", i.Args)
-	case Syscall:
-		return fmt.Sprintf("syscall%v", i.Args)
-	default:
-		return ""
-	}
+type Value interface {
+	AddUse(Value)
+	Alive() int
+	Dependencies() []Value
+	Equals(Value) bool
+	IsConst() bool
+	String() string
+	Token() token.Token
 }