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 package dev.openrs2.deob.ast.transform
import com.github.javaparser.ast.CompilationUnit 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.BinaryExpr
import com.github.javaparser.ast.expr.Expression import com.github.javaparser.ast.expr.Expression
import com.github.javaparser.ast.expr.IntegerLiteralExpr import com.github.javaparser.ast.expr.IntegerLiteralExpr
import com.github.javaparser.ast.expr.LongLiteralExpr import com.github.javaparser.ast.expr.LongLiteralExpr
import com.github.javaparser.ast.expr.UnaryExpr 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.Library
import dev.openrs2.deob.ast.LibraryGroup import dev.openrs2.deob.ast.LibraryGroup
import dev.openrs2.deob.ast.util.walk 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 { private fun Expression.isZero(): Boolean {

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