Add AssignExpr support to IdentityTransformer

It can now simplify expressions like `x += 0`.

Signed-off-by: Graham <gpe@openrs2.dev>
Graham 4 years ago
parent c98a24bff8
commit 222323eaa0
  1. 24
      deob-ast/src/main/java/dev/openrs2/deob/ast/transform/IdentityTransformer.kt

@ -1,11 +1,13 @@
package dev.openrs2.deob.ast.transform
import com.github.javaparser.ast.CompilationUnit
import com.github.javaparser.ast.expr.AssignExpr
import com.github.javaparser.ast.expr.BinaryExpr
import com.github.javaparser.ast.expr.Expression
import com.github.javaparser.ast.expr.IntegerLiteralExpr
import com.github.javaparser.ast.expr.LongLiteralExpr
import com.github.javaparser.ast.expr.UnaryExpr
import com.github.javaparser.ast.stmt.ExpressionStmt
import dev.openrs2.deob.ast.Library
import dev.openrs2.deob.ast.LibraryGroup
import dev.openrs2.deob.ast.util.walk
@ -46,6 +48,28 @@ class IdentityTransformer : Transformer() {
}
}
}
unit.walk { expr: AssignExpr ->
val identity = when (expr.operator) {
// x += 0, x -= 0
AssignExpr.Operator.PLUS, AssignExpr.Operator.MINUS -> expr.value.isZero()
// x *= 1, x /= 1
AssignExpr.Operator.MULTIPLY, AssignExpr.Operator.DIVIDE -> expr.value.isOne()
else -> false
}
if (!identity) {
return@walk
}
expr.parentNode.ifPresent { parent ->
if (parent is ExpressionStmt) {
parent.remove()
} else {
expr.replace(expr.target.clone())
}
}
}
}
private fun Expression.isZero(): Boolean {

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