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Commit 51fb7754 authored by Deepanshu Gupta's avatar Deepanshu Gupta
Browse files

LayoutLib: Fix System.arraycopy() 

Framework has specialized versions of java.lang.System.arraycopy() for
all primitive data types. These versions are not present on the Desktop
VM. This change replaces calls to any of the specialized versions with
the more general alternative - the one using Objects.

Note that this was already being done for char.

Change-Id: If1584125fea8ecc080fb39a5ee6cdb4d922d0c98
(cherry picked from commit e1960cc0)
parent 8db769dd

tools/layoutlib/create/README.txt

+2 −2
Original line number Diff line number Diff line
@@ -131,8 +131,8 @@ valid StackMapTable. As a side benefit of this, we can continue to support Java 
Mac has horrible font rendering support.



ReplaceMethodCallsAdapter replaces calls to certain methods. Currently, it only rewrites calls to

java.lang.System.arraycopy([CI[CII)V, which is not part of the Desktop VM to call the more general

method java.lang.System.arraycopy(Ljava/lang/Object;ILjava/lang/Object;II)V.

specialized versions of java.lang.System.arraycopy(), which are not part of the Desktop VM to call

the more general method java.lang.System.arraycopy(Ljava/lang/Object;ILjava/lang/Object;II)V.



The ClassAdapters are chained together to achieve the desired output. (Look at section 2.2.7

Transformation chains in the asm user guide, link in the References.) The order of execution of

tools/layoutlib/create/src/com/android/tools/layoutlib/create/AsmAnalyzer.java

+2 −2
Original line number Diff line number Diff line
@@ -726,9 +726,9 @@ public class AsmAnalyzer { 
                considerDesc(desc);





                // Check if method is java.lang.System.arrayCopy([CI[CII)V

                // Check if method is a specialized version of java.lang.System.arrayCopy()

                if (owner.equals("java/lang/System") && name.equals("arraycopy")

                        && desc.equals("([CI[CII)V")) {

                        && !desc.equals("(Ljava/lang/Object;ILjava/lang/Object;II)V")) {

                    mReplaceMethodCallClasses.add(mOwnerClass);

                }

            }

tools/layoutlib/create/src/com/android/tools/layoutlib/create/ReplaceMethodCallsAdapter.java

+19 −4
Original line number Diff line number Diff line
@@ -20,10 +20,23 @@ import org.objectweb.asm.ClassVisitor; 
import org.objectweb.asm.MethodVisitor;

import org.objectweb.asm.Opcodes;



import java.util.Arrays;

import java.util.HashSet;

import java.util.Set;



/**

 * Replaces calls to certain methods that do not exist in the Desktop VM.

 */

public class ReplaceMethodCallsAdapter extends ClassVisitor {



    /**

     * Descriptors for specialized versions {@link System#arraycopy} that are not present on the

     * Desktop VM.

     */

    private static Set<String> ARRAYCOPY_DESCRIPTORS = new HashSet<String>(Arrays.asList(

            "([CI[CII)V", "([BI[BII)V", "([SI[SII)V", "([II[III)V",

            "([JI[JII)V", "([FI[FII)V", "([DI[DII)V", "([ZI[ZII)V"));



    public ReplaceMethodCallsAdapter(ClassVisitor cv) {

        super(Opcodes.ASM4, cv);

    }
@@ -42,11 +55,13 @@ public class ReplaceMethodCallsAdapter extends ClassVisitor { 


        @Override

        public void visitMethodInsn(int opcode, String owner, String name, String desc) {

            // Check if method is java.lang.System.arrayCopy([CI[CII)V

            if (owner.equals("java/lang/System") && name.equals("arraycopy")

                    && desc.equals("([CI[CII)V")) {

            // Check if method is a specialized version of java.lang.System.arrayCopy

            if (owner.equals("java/lang/System") && name.equals("arraycopy")) {



                if (ARRAYCOPY_DESCRIPTORS.contains(desc)) {

                    desc = "(Ljava/lang/Object;ILjava/lang/Object;II)V";

                }

            }

            super.visitMethodInsn(opcode, owner, name, desc);

        }

    }