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Commit 9e771969 authored by Makoto Onuki's avatar Makoto Onuki
Browse files

Allow "experimental" class to be always loadable. 

Previously, when a class with <clinit> is "experimental", even
the "<clinit>" would throw, which would render the class to be
unloadable, which would cause lot of problems.

Now, "experimental API hook" returns a boolean. If it returns "false"
(instead of throwing), we skip the rest of the method body, which
essentially simulates `@Ignore`.

For now, only <clinit> can return false.

It'd be nice if we can support other methods too, but:
- <init> must call super.<init>, so we can't inject an early return.
- For other methods, generating a stack map frame was kind of painful
unless it's void.

Supporting non-<clinit> methods isn't really critical at all, so let's
just ignore it for now.

Bug: 292141694
Flag: TEST_ONLY
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh -r
Change-Id: I68e5356465a2e6c4ae053d406ef0740b77968685
parent e6020b6c

ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodExperimentalApiChecker.java

+8 −1
Original line number Diff line number Diff line
@@ -44,8 +44,15 @@ public class RavenwoodExperimentalApiChecker { 
     * Check if experimental APIs are enabled, and if not, throws

     * {@link RavenwoodUnsupportedApiException}.

     */

    public static void onExperimentalApiCalled(Class<?> clazz, String method, String desc) {

    public static boolean onExperimentalApiCalled(Class<?> clazz, String method, String desc) {

        // Even when experimental APIs are disabled, we don't want to throw from <clinit>.

        // because that'd make the class unloadable. Instead, we return false to skip the rest of

        // the code.

        if ("<clinit>".equals(method)) {

            return isExperimentalApiEnabled();

        }

        onExperimentalApiCalled(2);

        return true;

    }



    /**

ravenwood/tools/hoststubgen/helper-runtime-src/com/android/hoststubgen/hosthelper/HostTestUtils.java

+24 −0
Original line number Diff line number Diff line
@@ -21,6 +21,9 @@ import java.lang.reflect.AnnotatedElement; 
 * Utilities used in the host side test environment.

 */

public class HostTestUtils {

    public static final String CLASS_INTERNAL_NAME = getInternalName(HostTestUtils.class);

    public static final  String CLASS_DESCRIPTOR = "L" + CLASS_INTERNAL_NAME + ";";



    private HostTestUtils() {

    }
@@ -58,4 +61,25 @@ public class HostTestUtils { 
        }

        return null;

    }



    public static final String ASSERT_THAT_HOOK_RETURNED_TRUE = "assertThatHookReturnedTrue";

    public static final String ASSERT_THAT_HOOK_RETURNED_FALSE = "assertThatHookReturnedFalse";



    /**

     * Used to assert a boolean method returned true.

     */

    public static void assertThatHookReturnedTrue(boolean b) {

        if (!b) {

            throw new IllegalStateException("The hook must return true for this method");

        }

    }



    /**

     * Used to assert a boolean method returned false.

     */

    public static void assertThatHookReturnedFalse(boolean b) {

        if (b) {

            throw new IllegalStateException("The hook must return false for this method");

        }

    }

}

ravenwood/tools/hoststubgen/lib/com/android/hoststubgen/asm/AsmUtils.kt

+42 −0
Original line number Diff line number Diff line
@@ -268,6 +268,37 @@ fun writeByteCodeToReturn(methodDescriptor: String, writer: MethodVisitor) { 
    }

}



/**

 * Write bytecode to "RETURN" that matches the method's return type with the type's empty value,

 * according to [methodDescriptor].

 */

fun writeByteCodeToReturnDefault(methodDescriptor: String, writer: MethodVisitor) {

    when (Type.getReturnType(methodDescriptor)) {

        Type.VOID_TYPE -> writer.visitInsn(Opcodes.RETURN)

        Type.BOOLEAN_TYPE, Type.BYTE_TYPE, Type.CHAR_TYPE, Type.SHORT_TYPE,

        Type.INT_TYPE -> {

            writer.visitInsn(Opcodes.ICONST_0)

            writer.visitInsn(Opcodes.IRETURN)

        }

        Type.LONG_TYPE -> {

            writer.visitInsn(Opcodes.LCONST_0)

            writer.visitInsn(Opcodes.LRETURN)

        }

        Type.FLOAT_TYPE -> {

            writer.visitInsn(Opcodes.FCONST_0)

            writer.visitInsn(Opcodes.FRETURN)

        }

        Type.DOUBLE_TYPE -> {

            writer.visitInsn(Opcodes.DCONST_0)

            writer.visitInsn(Opcodes.DRETURN)

        }

        else -> {

            writer.visitInsn(Opcodes.ACONST_NULL)

            writer.visitInsn(Opcodes.ARETURN)

        }

    }

}



/**

 * Write bytecode to pop the 2 uninitialized instances out of the stack

 * after performing constructor redirection.
@@ -553,3 +584,14 @@ abstract class UnifiedVisitor { 
        }

    }

}



/**

 * Data class to store visitFrame() arguments.

 */

data class FrameInfo(

    var type: Int,

    var numLocal: Int,

    var local: Array<out Any?>?,

    var numStack: Int,

    var stack: Array<out Any?>?

)
 
 No newline at end of file

ravenwood/tools/hoststubgen/lib/com/android/hoststubgen/visitors/ImplGeneratingAdapter.kt

+78 −26
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
package com.android.hoststubgen.visitors



import com.android.hoststubgen.HostStubGenErrors

import com.android.hoststubgen.HostStubGenInternalException

import com.android.hoststubgen.asm.CLASS_INITIALIZER_DESC

import com.android.hoststubgen.asm.CLASS_INITIALIZER_NAME

import com.android.hoststubgen.asm.CTOR_NAME
@@ -31,6 +32,7 @@ import com.android.hoststubgen.asm.reasonParam 
import com.android.hoststubgen.asm.toJvmClassName

import com.android.hoststubgen.asm.writeByteCodeToPushArguments

import com.android.hoststubgen.asm.writeByteCodeToReturn

import com.android.hoststubgen.asm.writeByteCodeToReturnDefault

import com.android.hoststubgen.filters.FilterPolicy

import com.android.hoststubgen.filters.FilterPolicyWithReason

import com.android.hoststubgen.filters.OutputFilter
@@ -40,12 +42,13 @@ import com.android.hoststubgen.hosthelper.HostStubGenProcessedAsKeep 
import com.android.hoststubgen.hosthelper.HostStubGenProcessedAsSubstitute

import com.android.hoststubgen.hosthelper.HostStubGenProcessedAsThrow

import com.android.hoststubgen.hosthelper.HostStubGenProcessedAsThrowButSupported

import com.android.hoststubgen.hosthelper.HostTestUtils

import com.android.hoststubgen.log

import com.android.hoststubgen.utils.ClassDescriptorSet

import java.lang.annotation.RetentionPolicy

import org.objectweb.asm.AnnotationVisitor

import org.objectweb.asm.ClassVisitor

import org.objectweb.asm.FieldVisitor

import org.objectweb.asm.Label

import org.objectweb.asm.MethodVisitor

import org.objectweb.asm.Opcodes

import org.objectweb.asm.Opcodes.INVOKEINTERFACE
@@ -53,6 +56,7 @@ import org.objectweb.asm.Opcodes.INVOKESPECIAL 
import org.objectweb.asm.Opcodes.INVOKESTATIC

import org.objectweb.asm.Opcodes.INVOKEVIRTUAL

import org.objectweb.asm.Type

import java.lang.annotation.RetentionPolicy



const val OPCODE_VERSION = Opcodes.ASM9
@@ -444,7 +448,7 @@ class ImplGeneratingAdapter( 
                    }

                    log.v("Making method experimental...")

                    innerVisitor = innerVisitor?.let {

                        MethodCallHookInjectingAdapter(

                        ReturnDecidingMethodCallHookInjectingAdapter(

                            name,

                            descriptor,

                            listOf(options.experimentalMethodCallHook!!),
@@ -497,30 +501,7 @@ class ImplGeneratingAdapter( 
        next: MethodVisitor?

    ) : BodyReplacingMethodVisitor(createBody, next) {

        override fun emitNewCode() {

            when (Type.getReturnType(descriptor)) {

                Type.VOID_TYPE -> visitInsn(Opcodes.RETURN)

                Type.BOOLEAN_TYPE, Type.BYTE_TYPE, Type.CHAR_TYPE, Type.SHORT_TYPE,

                Type.INT_TYPE -> {

                    visitInsn(Opcodes.ICONST_0)

                    visitInsn(Opcodes.IRETURN)

                }

                Type.LONG_TYPE -> {

                    visitInsn(Opcodes.LCONST_0)

                    visitInsn(Opcodes.LRETURN)

                }

                Type.FLOAT_TYPE -> {

                    visitInsn(Opcodes.FCONST_0)

                    visitInsn(Opcodes.FRETURN)

                }

                Type.DOUBLE_TYPE -> {

                    visitInsn(Opcodes.DCONST_0)

                    visitInsn(Opcodes.DRETURN)

                }

                else -> {

                    visitInsn(Opcodes.ACONST_NULL)

                    visitInsn(Opcodes.ARETURN)

                }

            }

            writeByteCodeToReturnDefault(descriptor, this)

            visitMaxs(0, 0) // We let ASM figure them out.

        }

    }
@@ -604,6 +585,77 @@ class ImplGeneratingAdapter( 
        }

    }





    /**

     * Similar to [MethodCallHookInjectingAdapter], but the hook must return boolean.

     *

     * The hook must always return true, except in <clinit>, it can return false. If the hook

     * returns false, we return from the method, without running any of the remaining code.

     *

     * Can we use false for other methods?

     * - No, for <init>, beucase we always must call super's <init>. We can never return

     *   early from <init.

     * - For other methods, we could.

     */

    private inner class ReturnDecidingMethodCallHookInjectingAdapter(

        val name: String,

        val descriptor: String,

        val hooks: List<String>,

        next: MethodVisitor?,

    ) : MethodVisitor(OPCODE_VERSION, next) {

        /**

         * Whether or not the hook can return false to skip the rest of the method body.

         */

        val allowReturn = name == "<clinit>"



        override fun visitCode() {

            super.visitCode() // Note it's possible nested visitor added code too



            hooks.forEach { hook ->

                mv.visitLdcInsn(Type.getType("L$currentClassName;"))

                visitLdcInsn(name)

                visitLdcInsn(descriptor)



                val (clazz, method) = hook.parseClassMethod()

                visitMethodInsn(INVOKESTATIC, clazz, method,

                    "(Ljava/lang/Class;Ljava/lang/String;Ljava/lang/String;)Z",

                    false

                )

                if (!allowReturn) {

                    // We don't allow "return". The hook must always return true.

                    visitMethodInsn(INVOKESTATIC, HostTestUtils.CLASS_INTERNAL_NAME,

                        HostTestUtils.ASSERT_THAT_HOOK_RETURNED_TRUE,

                        "(Z)V",

                        false

                    )

                } else {

                    var label = Label()



                    visitJumpInsn(Opcodes.IFNE, label)

                    if (Type.getReturnType(descriptor) != Type.VOID_TYPE) {

                        // If we ever want to use it for non-void method,

                        // The below visitFrame() call needs to accommodate that.

                        // (Need some investigation to implement it properly...)

                        throw HostStubGenInternalException(

                            "This feature for non-void method isn't implemented yet")

                    }

                    writeByteCodeToReturnDefault(descriptor, this)



                    visitLabel(label)



                    // We need to inject a frame.

                    //

                    // We assume our method cal is the first thing we do in this method

                    // and the frame can be empty.

                    // In reality, it's possible the "next" visitors created more with frames,

                    // in super.visitCode(), in that case this would probably break...

                    //

                    super.visitFrame(Opcodes.F_NEW, 0, null, 0, null)

                }

            }

        }

    }



    /**

     * Inject a class load hook call.

     */

ravenwood/tools/hoststubgen/test-tiny-framework/golden-output/hoststubgen-test-tiny-framework-host-dump.txt

+141 −28

File changed.

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