/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.dx;
import com.android.dx.rop.code.BasicBlockList;
import com.android.dx.rop.code.Insn;
import com.android.dx.rop.code.PlainCstInsn;
import com.android.dx.rop.code.PlainInsn;
import com.android.dx.rop.code.RegisterSpecList;
import com.android.dx.rop.code.Rop;
import com.android.dx.rop.code.Rops;
import com.android.dx.rop.code.SourcePosition;
import com.android.dx.rop.code.ThrowingCstInsn;
import com.android.dx.rop.code.ThrowingInsn;
import com.android.dx.rop.cst.CstInteger;
import com.android.dx.rop.type.StdTypeList;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import static com.android.dx.rop.code.Rop.BRANCH_GOTO;
import static com.android.dx.rop.code.Rop.BRANCH_NONE;
import static com.android.dx.rop.code.Rop.BRANCH_RETURN;
import static com.android.dx.rop.type.Type.BT_BYTE;
import static com.android.dx.rop.type.Type.BT_CHAR;
import static com.android.dx.rop.type.Type.BT_INT;
import static com.android.dx.rop.type.Type.BT_SHORT;
/**
* Builds a sequence of instructions.
*
* <h3>Locals</h3>
* All data manipulation takes place in local variables. Each parameter gets its
* own local by default; access these using {@link #getParameter
* getParameter()}. Non-static methods and constructors also have a {@code this}
* parameter; it's available as {@link #getThis getThis()}. Allocate a new local
* variable using {@link #newLocal newLocal()}, and assign a default value to it
* with {@link #loadConstant loadConstant()}. Copy a value from one local to
* another with {@link #move move()}.
*
* <p>Every local variable has a fixed type. This is either a primitive type (of
* any size) or a reference type. This class emits instructions appropriate to
* the types they operate on. Not all operations are local on all types;
* attempting to emit such an operation will fail with an unchecked exception.
*
* <h3>Math and Bit Operations</h3>
* Transform a single value into another related value using {@link
* #op(UnaryOp,Local,Local) op(UnaryOp, Local, Local)}. Transform two values
* into a third value using {@link #op(BinaryOp,Local,Local,Local) op(BinaryOp,
* Local, Local, Local)}. In either overload the first {@code Local} parameter
* is where the result will be sent; the other {@code Local} parameters are the
* inputs.
*
* <h3>Comparisons</h3>
* There are three different comparison operations each with different
* constraints:
* <ul>
* <li>{@link #compareLongs compareLongs()} compares two locals each
* containing a {@code long} primitive. This is the only operation that
* can compare longs. The result of the comparison is written to another
* {@code int} local.</li>
* <li>{@link #compareFloatingPoint compareFloatingPoint()} compares two
* locals; both {@code float} primitives or both {@code double}
* primitives. This is the only operation that can compare floating
* point values. This comparison takes an extra parameter that sets
* the desired result if either parameter is {@code NaN}. The result of
* the comparison is wrtten to another {@code int} local.
* <li>{@link #compare compare()} compares two locals. The {@link
* Comparison#EQ} and {@link Comparison#NE} options compare either
* {@code int} primitives or references. The other options compare only
* {@code int} primitives. This comparison takes a {@link Label} that
* will be jumped to if the comparison is true. If the comparison is
* false the next instruction in sequence will be executed.
* </ul>
* There's no single operation to compare longs and jump, or to compare ints and
* store the result in a local. Accomplish these goals by chaining multiple
* operations together.
*
* <h3>Branches, Labels and Returns</h3>
* Basic control flow is expressed using jumps and labels. Each label must be
* marked exactly once and may be jumped to any number of times. Create a label
* using its constructor: {@code new Label()}, and mark it using {@link #mark
* mark(Label)}. All jumps to a label will execute instructions starting from
* that label. You can jump to a label that hasn't yet been marked (jumping
* forward) or to a label that has already been marked (jumping backward). Jump
* unconditionally with {@link #jump jump(Label)} or conditionally based on a
* comparison using {@link #compare compare()}.
*
* <p>Most methods should contain a return instruction. Void methods
* should use {@link #returnVoid()}; non-void methods should use {@link
* #returnValue returnValue()} with a local whose return type matches the
* method's return type. Constructors are considered void methods and should
* call {@link #returnVoid()}. Methods may make multiple returns. Methods
* containing no return statements must either loop infinitely or throw
* unconditionally; it is not legal to end a sequence of instructions without a
* jump, return or throw.
*
* <h3>Throwing and Catching</h3>
* This API uses labels to handle thrown exceptions, errors and throwables. Call
* {@link #addCatchClause addCatchClause()} to register the target label and
* throwable class. All statements that follow will jump to that catch clause if
* they throw a {@link Throwable} assignable to that type. Use {@link
* #removeCatchClause removeCatchClause()} to unregister the throwable class.
*
* <p>Throw an throwable by first assigning it to a local and then calling
* {@link #throwValue throwValue()}. Control flow will jump to the nearest label
* assigned to a type assignable to the thrown type. In this context, "nearest"
* means the label requiring the fewest stack frames to be popped.
*
* <h3>Calling methods</h3>
* A method's caller must know its return type, name, parameters, and invoke
* kind. Lookup a method on a type using {@link TypeId#getMethod
* TypeId.getMethod()}. This is more onerous than Java language invokes, which
* can infer the target method using the target object and parameters. There are
* four invoke kinds:
* <ul>
* <li>{@link #invokeStatic invokeStatic()} is used for static methods.</li>
* <li>{@link #invokeDirect invokeDirect()} is used for private instance
* methods and for constructors to call their superclass's
* constructor.</li>
* <li>{@link #invokeInterface invokeInterface()} is used to invoke a method
* whose declaring type is an interface.</li>
* <li>{@link #invokeVirtual invokeVirtual()} is used to invoke any other
* method. The target must not be static, private, a constructor, or an
* interface method.</li>
* <li>{@link #invokeSuper invokeSuper()} is used to invoke the closest
* superclass's virtual method. The target must not be static, private,
* a constructor method, or an interface method.</li>
* <li>{@link #newInstance newInstance()} is used to invoke a
* constructor.</li>
* </ul>
* All invoke methods take a local for the return value. For void methods this
* local is unused and may be null.
*
* <h3>Field Access</h3>
* Read static fields using {@link #sget sget()}; write them using {@link
* #sput sput()}. For instance values you'll need to specify the declaring
* instance; use {@link #getThis getThis()} in an instance method to use {@code
* this}. Read instance values using {@link #iget iget()} and write them with
* {@link #iput iput()}.
*
* <h3>Array Access</h3>
* Allocate an array using {@link #newArray newArray()}. Read an array's length
* with {@link #arrayLength arrayLength()} and its elements with {@link #aget
* aget()}. Write an array's elements with {@link #aput aput()}.
*
* <h3>Types</h3>
* Use {@link #cast cast()} to perform either a <strong>numeric cast</strong> or
* a <strong>type cast</strong>. Interrogate the type of a value in a local
* using {@link #instanceOfType instanceOfType()}.
*
* <h3>Synchronization</h3>
* Acquire a monitor using {@link #monitorEnter monitorEnter()}; release it with
* {@link #monitorExit monitorExit()}. It is the caller's responsibility to
* guarantee that enter and exit calls are balanced, even in the presence of
* exceptions thrown.
*
* <strong>Warning:</strong> Even if a method has the {@code synchronized} flag,
* dex requires instructions to acquire and release monitors manually. A method
* declared with {@link java.lang.reflect.Modifier#SYNCHRONIZED SYNCHRONIZED}
* but without manual calls to {@code monitorEnter()} and {@code monitorExit()}
* will not be synchronized when executed.
*/
public final class Code {
private final MethodId<?, ?> method;
/**
* All allocated labels. Although the order of the labels in this list
* shouldn't impact behavior, it is used to determine basic block indices.
*/
private final List<Label> labels = new ArrayList<Label>();
/**
* The label currently receiving instructions. This is null if the most
* recent instruction was a return or goto.
*/
private Label currentLabel;
/** true once we've fixed the positions of the parameter registers */
private boolean localsInitialized;
private final Local<?> thisLocal;
/**
* The parameters on this method. If this is non-static, the first parameter
* is 'thisLocal' and we have to offset the user's indices by one.
*/
private final List<Local<?>> parameters = new ArrayList<Local<?>>();
private final List<Local<?>> locals = new ArrayList<Local<?>>();
private SourcePosition sourcePosition = SourcePosition.NO_INFO;
private final List<TypeId<?>> catchTypes = new ArrayList<TypeId<?>>();
private final List<Label> catchLabels = new ArrayList<Label>();
private StdTypeList catches = StdTypeList.EMPTY;
Code(DexMaker.MethodDeclaration methodDeclaration) {
this.method = methodDeclaration.method;
if (methodDeclaration.isStatic()) {
thisLocal = null;
} else {
thisLocal = Local.get(this, method.declaringType);
parameters.add(thisLocal);
}
for (TypeId<?> parameter : method.parameters.types) {
parameters.add(Local.get(this, parameter));
}
this.currentLabel = new Label();
adopt(this.currentLabel);
this.currentLabel.marked = true;
}
/**
* Allocates a new local variable of type {@code type}. It is an error to
* allocate a local after instructions have been emitted.
*/
public <T> Local<T> newLocal(TypeId<T> type) {
if (localsInitialized) {
throw new IllegalStateException("Cannot allocate locals after adding instructions");
}
Local<T> result = Local.get(this, type);
locals.add(result);
return result;
}
/**
* Returns the local for the parameter at index {@code index} and of type
* {@code type}.
*/
public <T> Local<T> getParameter(int index, TypeId<T> type) {
if (thisLocal != null) {
index++; // adjust for the hidden 'this' parameter
}
return coerce(parameters.get(index), type);
}
/**
* Returns the local for {@code this} of type {@code type}. It is an error
* to call {@code getThis()} if this is a static method.
*/
public <T> Local<T> getThis(TypeId<T> type) {
if (thisLocal == null) {
throw new IllegalStateException("static methods cannot access 'this'");
}
return coerce(thisLocal, type);
}
@SuppressWarnings("unchecked") // guarded by an equals check
private <T> Local<T> coerce(Local<?> local, TypeId<T> expectedType) {
if (!local.type.equals(expectedType)) {
throw new IllegalArgumentException(
"requested " + expectedType + " but was " + local.type);
}
return (Local<T>) local;
}
/**
* Assigns registers to locals. From the spec:
* "the N arguments to a method land in the last N registers of the
* method's invocation frame, in order. Wide arguments consume two
* registers. Instance methods are passed a this reference as their
* first argument."
*
* In addition to assigning registers to each of the locals, this creates
* instructions to move parameters into their initial registers. These
* instructions are inserted before the code's first real instruction.
*/
void initializeLocals() {
if (localsInitialized) {
throw new AssertionError();
}
localsInitialized = true;
int reg = 0;
for (Local<?> local : locals) {
reg += local.initialize(reg);
}
int firstParamReg = reg;
List<Insn> moveParameterInstructions = new ArrayList<Insn>();
for (Local<?> local : parameters) {
CstInteger paramConstant = CstInteger.make(reg - firstParamReg);
reg += local.initialize(reg);
moveParameterInstructions.add(new PlainCstInsn(Rops.opMoveParam(local.type.ropType),
sourcePosition, local.spec(), RegisterSpecList.EMPTY, paramConstant));
}
labels.get(0).instructions.addAll(0, moveParameterInstructions);
}
/**
* Returns the number of registers to hold the parameters. This includes the
* 'this' parameter if it exists.
*/
int paramSize() {
int result = 0;
for (Local<?> local : parameters) {
result += local.size();
}
return result;
}
// labels
/**
* Assigns {@code target} to this code.
*/
private void adopt(Label target) {
if (target.code == this) {
return; // already adopted
}
if (target.code != null) {
throw new IllegalArgumentException("Cannot adopt label; it belongs to another Code");
}
target.code = this;
labels.add(target);
}
/**
* Start defining instructions for the named label.
*/
public void mark(Label label) {
adopt(label);
if (label.marked) {
throw new IllegalStateException("already marked");
}
label.marked = true;
if (currentLabel != null) {
jump(label); // blocks must end with a branch, return or throw
}
currentLabel = label;
}
/**
* Transfers flow control to the instructions at {@code target}. It is an
* error to jump to a label not marked on this {@code Code}.
*/
public void jump(Label target) {
adopt(target);
addInstruction(new PlainInsn(Rops.GOTO, sourcePosition, null, RegisterSpecList.EMPTY),
target);
}
/**
* Registers {@code catchClause} as a branch target for all instructions
* in this frame that throw a class assignable to {@code toCatch}. This
* includes methods invoked from this frame. Deregister the clause using
* {@link #removeCatchClause removeCatchClause()}. It is an error to
* register a catch clause without also {@link #mark marking it} in the same
* {@code Code} instance.
*/
public void addCatchClause(TypeId<? extends Throwable> toCatch, Label catchClause) {
if (catchTypes.contains(toCatch)) {
throw new IllegalArgumentException("Already caught: " + toCatch);
}
adopt(catchClause);
catchTypes.add(toCatch);
catches = toTypeList(catchTypes);
catchLabels.add(catchClause);
}
/**
* Deregisters the catch clause label for {@code toCatch} and returns it.
*/
public Label removeCatchClause(TypeId<? extends Throwable> toCatch) {
int index = catchTypes.indexOf(toCatch);
if (index == -1) {
throw new IllegalArgumentException("No catch clause: " + toCatch);
}
catchTypes.remove(index);
catches = toTypeList(catchTypes);
return catchLabels.remove(index);
}
/**
* Throws the throwable in {@code toThrow}.
*/
public void throwValue(Local<? extends Throwable> toThrow) {
addInstruction(new ThrowingInsn(Rops.THROW, sourcePosition,
RegisterSpecList.make(toThrow.spec()), catches));
}
private StdTypeList toTypeList(List<TypeId<?>> types) {
StdTypeList result = new StdTypeList(types.size());
for (int i = 0; i < types.size(); i++) {
result.set(i, types.get(i).ropType);
}
return result;
}
private void addInstruction(Insn insn) {
addInstruction(insn, null);
}
/**
* @param branch the branches to follow; interpretation depends on the
* instruction's branchingness.
*/
private void addInstruction(Insn insn, Label branch) {
if (currentLabel == null || !currentLabel.marked) {
throw new IllegalStateException("no current label");
}
currentLabel.instructions.add(insn);
switch (insn.getOpcode().getBranchingness()) {
case BRANCH_NONE:
if (branch != null) {
throw new IllegalArgumentException("unexpected branch: " + branch);
}
return;
case BRANCH_RETURN:
if (branch != null) {
throw new IllegalArgumentException("unexpected branch: " + branch);
}
currentLabel = null;
break;
case BRANCH_GOTO:
if (branch == null) {
throw new IllegalArgumentException("branch == null");
}
currentLabel.primarySuccessor = branch;
currentLabel = null;
break;
case Rop.BRANCH_IF:
if (branch == null) {
throw new IllegalArgumentException("branch == null");
}
splitCurrentLabel(branch, Collections.<Label>emptyList());
break;
case Rop.BRANCH_THROW:
if (branch != null) {
throw new IllegalArgumentException("unexpected branch: " + branch);
}
splitCurrentLabel(null, new ArrayList<Label>(catchLabels));
break;
default:
throw new IllegalArgumentException();
}
}
/**
* Closes the current label and starts a new one.
*
* @param catchLabels an immutable list of catch labels
*/
private void splitCurrentLabel(Label alternateSuccessor, List<Label> catchLabels) {
Label newLabel = new Label();
adopt(newLabel);
currentLabel.primarySuccessor = newLabel;
currentLabel.alternateSuccessor = alternateSuccessor;
currentLabel.catchLabels = catchLabels;
currentLabel = newLabel;
currentLabel.marked = true;
}
// instructions: locals
/**
* Copies the constant value {@code value} to {@code target}. The constant
* must be a primitive, String, Class, TypeId, or null.
*/
public <T> void loadConstant(Local<T> target, T value) {
Rop rop = value == null
? Rops.CONST_OBJECT_NOTHROW
: Rops.opConst(target.type.ropType);
if (rop.getBranchingness() == BRANCH_NONE) {
addInstruction(new PlainCstInsn(rop, sourcePosition, target.spec(),
RegisterSpecList.EMPTY, Constants.getConstant(value)));
} else {
addInstruction(new ThrowingCstInsn(rop, sourcePosition,
RegisterSpecList.EMPTY, catches, Constants.getConstant(value)));
moveResult(target, true);
}
}
/**
* Copies the value in {@code source} to {@code target}.
*/
public <T> void move(Local<T> target, Local<T> source) {
addInstruction(new PlainInsn(Rops.opMove(source.type.ropType),
sourcePosition, target.spec(), source.spec()));
}
// instructions: unary and binary
/**
* Executes {@code op} and sets {@code target} to the result.
*/
public <T> void op(UnaryOp op, Local<T> target, Local<T> source) {
addInstruction(new PlainInsn(op.rop(source.type), sourcePosition,
target.spec(), source.spec()));
}
/**
* Executes {@code op} and sets {@code target} to the result. For most
* binary operations, the types of {@code a} and {@code b} must be the same.
* Shift operations (like {@link BinaryOp#SHIFT_LEFT}) require {@code b} to
* be an {@code int}, even when {@code a} is a {@code long}.
*/
public <T1, T2> void op(BinaryOp op, Local<T1> target, Local<T1> a, Local<T2> b) {
Rop rop = op.rop(StdTypeList.make(a.type.ropType, b.type.ropType));
RegisterSpecList sources = RegisterSpecList.make(a.spec(), b.spec());
if (rop.getBranchingness() == BRANCH_NONE) {
addInstruction(new PlainInsn(rop, sourcePosition, target.spec(), sources));
} else {
addInstruction(new ThrowingInsn(rop, sourcePosition, sources, catches));
moveResult(target, true);
}
}
// instructions: branches
/**
* Compare ints or references. If the comparison is true, execution jumps to
* {@code trueLabel}. If it is false, execution continues to the next
* instruction.
*/
public <T> void compare(Comparison comparison, Label trueLabel, Local<T> a, Local<T> b) {
adopt(trueLabel);
Rop rop = comparison.rop(StdTypeList.make(a.type.ropType, b.type.ropType));
addInstruction(new PlainInsn(rop, sourcePosition, null,
RegisterSpecList.make(a.spec(), b.spec())), trueLabel);
}
/**
* Check if an int or reference equals to zero. If the comparison is true,
* execution jumps to {@code trueLabel}. If it is false, execution continues to
* the next instruction.
*/
public <T> void compareZ(Comparison comparison, Label trueLabel, Local<?> a) {
adopt(trueLabel);
Rop rop = comparison.rop(StdTypeList.make(a.type.ropType));
addInstruction(new PlainInsn(rop, sourcePosition, null,
RegisterSpecList.make(a.spec())), trueLabel);
}
/**
* Compare floats or doubles. This stores -1 in {@code target} if {@code
* a < b}, 0 in {@code target} if {@code a == b} and 1 in target if {@code
* a > b}. This stores {@code nanValue} in {@code target} if either value
* is {@code NaN}.
*/
public <T extends Number> void compareFloatingPoint(
Local<Integer> target, Local<T> a, Local<T> b, int nanValue) {
Rop rop;
if (nanValue == 1) {
rop = Rops.opCmpg(a.type.ropType);
} else if (nanValue == -1) {
rop = Rops.opCmpl(a.type.ropType);
} else {
throw new IllegalArgumentException("expected 1 or -1 but was " + nanValue);
}
addInstruction(new PlainInsn(rop, sourcePosition, target.spec(),
RegisterSpecList.make(a.spec(), b.spec())));
}
/**
* Compare longs. This stores -1 in {@code target} if {@code
* a < b}, 0 in {@code target} if {@code a == b} and 1 in target if {@code
* a > b}.
*/
public void compareLongs(Local<Integer> target, Local<Long> a, Local<Long> b) {
addInstruction(new PlainInsn(Rops.CMPL_LONG, sourcePosition, target.spec(),
RegisterSpecList.make(a.spec(), b.spec())));
}
// instructions: fields
/**
* Copies the value in instance field {@code fieldId} of {@code instance} to
* {@code target}.
*/
public <D, V> void iget(FieldId<D, ? extends V> fieldId, Local<V> target, Local<D> instance) {
addInstruction(new ThrowingCstInsn(Rops.opGetField(target.type.ropType), sourcePosition,
RegisterSpecList.make(instance.spec()), catches, fieldId.constant));
moveResult(target, true);
}
/**
* Copies the value in {@code source} to the instance field {@code fieldId}
* of {@code instance}.
*/
public <D, V> void iput(FieldId<D, V> fieldId, Local<? extends D> instance, Local<? extends V> source) {
addInstruction(new ThrowingCstInsn(Rops.opPutField(source.type.ropType), sourcePosition,
RegisterSpecList.make(source.spec(), instance.spec()), catches, fieldId.constant));
}
/**
* Copies the value in the static field {@code fieldId} to {@code target}.
*/
public <V> void sget(FieldId<?, ? extends V> fieldId, Local<V> target) {
addInstruction(new ThrowingCstInsn(Rops.opGetStatic(target.type.ropType), sourcePosition,
RegisterSpecList.EMPTY, catches, fieldId.constant));
moveResult(target, true);
}
/**
* Copies the value in {@code source} to the static field {@code fieldId}.
*/
public <V> void sput(FieldId<?, V> fieldId, Local<? extends V> source) {
addInstruction(new ThrowingCstInsn(Rops.opPutStatic(source.type.ropType), sourcePosition,
RegisterSpecList.make(source.spec()), catches, fieldId.constant));
}
// instructions: invoke
/**
* Calls the constructor {@code constructor} using {@code args} and assigns
* the new instance to {@code target}.
*/
public <T> void newInstance(Local<T> target, MethodId<T, Void> constructor, Local<?>... args) {
if (target == null) {
throw new IllegalArgumentException();
}
addInstruction(new ThrowingCstInsn(Rops.NEW_INSTANCE, sourcePosition,
RegisterSpecList.EMPTY, catches, constructor.declaringType.constant));
moveResult(target, true);
invokeDirect(constructor, null, target, args);
}
/**
* Calls the static method {@code method} using {@code args} and assigns the
* result to {@code target}.
*
* @param target the local to receive the method's return value, or {@code
* null} if the return type is {@code void} or if its value not needed.
*/
public <R> void invokeStatic(MethodId<?, R> method, Local<? super R> target, Local<?>... args) {
invoke(Rops.opInvokeStatic(method.prototype(true)), method, target, null, args);
}
/**
* Calls the non-private instance method {@code method} of {@code instance}
* using {@code args} and assigns the result to {@code target}.
*
* @param method a non-private, non-static, method declared on a class. May
* not be an interface method or a constructor.
* @param target the local to receive the method's return value, or {@code
* null} if the return type is {@code void} or if its value not needed.
*/
public <D, R> void invokeVirtual(MethodId<D, R> method, Local<? super R> target,
Local<? extends D> instance, Local<?>... args) {
invoke(Rops.opInvokeVirtual(method.prototype(true)), method, target, instance, args);
}
/**
* Calls {@code method} of {@code instance} using {@code args} and assigns
* the result to {@code target}.
*
* @param method either a private method or the superclass's constructor in
* a constructor's call to {@code super()}.
* @param target the local to receive the method's return value, or {@code
* null} if the return type is {@code void} or if its value not needed.
*/
public <D, R> void invokeDirect(MethodId<D, R> method, Local<? super R> target,
Local<? extends D> instance, Local<?>... args) {
invoke(Rops.opInvokeDirect(method.prototype(true)), method, target, instance, args);
}
/**
* Calls the closest superclass's virtual method {@code method} of {@code
* instance} using {@code args} and assigns the result to {@code target}.
*
* @param target the local to receive the method's return value, or {@code
* null} if the return type is {@code void} or if its value not needed.
*/
public <D, R> void invokeSuper(MethodId<D, R> method, Local<? super R> target,
Local<? extends D> instance, Local<?>... args) {
invoke(Rops.opInvokeSuper(method.prototype(true)), method, target, instance, args);
}
/**
* Calls the interface method {@code method} of {@code instance} using
* {@code args} and assigns the result to {@code target}.
*
* @param method a method declared on an interface.
* @param target the local to receive the method's return value, or {@code
* null} if the return type is {@code void} or if its value not needed.
*/
public <D, R> void invokeInterface(MethodId<D, R> method, Local<? super R> target,
Local<? extends D> instance, Local<?>... args) {
invoke(Rops.opInvokeInterface(method.prototype(true)), method, target, instance, args);
}
private <D, R> void invoke(Rop rop, MethodId<D, R> method, Local<? super R> target,
Local<? extends D> object, Local<?>... args) {
addInstruction(new ThrowingCstInsn(rop, sourcePosition, concatenate(object, args),
catches, method.constant));
if (target != null) {
moveResult(target, false);
}
}
// instructions: types
/**
* Tests if the value in {@code source} is assignable to {@code type}. If it
* is, {@code target} is assigned to 1; otherwise {@code target} is assigned
* to 0.
*/
public void instanceOfType(Local<?> target, Local<?> source, TypeId<?> type) {
addInstruction(new ThrowingCstInsn(Rops.INSTANCE_OF, sourcePosition,
RegisterSpecList.make(source.spec()), catches, type.constant));
moveResult(target, true);
}
/**
* Performs either a numeric cast or a type cast.
*
* <h3>Numeric Casts</h3>
* Converts a primitive to a different representation. Numeric casts may
* be lossy. For example, converting the double {@code 1.8d} to an integer
* yields {@code 1}, losing the fractional part. Converting the integer
* {@code 0x12345678} to a short yields {@code 0x5678}, losing the high
* bytes. The following numeric casts are supported:
*
* <p><table border="1" summary="Supported Numeric Casts">
* <tr><th>From</th><th>To</th></tr>
* <tr><td>int</td><td>byte, char, short, long, float, double</td></tr>
* <tr><td>long</td><td>int, float, double</td></tr>
* <tr><td>float</td><td>int, long, double</td></tr>
* <tr><td>double</td><td>int, long, float</td></tr>
* </table>
*
* <p>For some primitive conversions it will be necessary to chain multiple
* cast operations. For example, to go from float to short one would first
* cast float to int and then int to short.
*
* <p>Numeric casts never throw {@link ClassCastException}.
*
* <h3>Type Casts</h3>
* Checks that a reference value is assignable to the target type. If it is
* assignable it is copied to the target local. If it is not assignable a
* {@link ClassCastException} is thrown.
*/
public void cast(Local<?> target, Local<?> source) {
if (source.getType().ropType.isReference()) {
addInstruction(new ThrowingCstInsn(Rops.CHECK_CAST, sourcePosition,
RegisterSpecList.make(source.spec()), catches, target.type.constant));
moveResult(target, true);
} else {
addInstruction(new PlainInsn(getCastRop(source.type.ropType, target.type.ropType),
sourcePosition, target.spec(), source.spec()));
}
}
private Rop getCastRop(com.android.dx.rop.type.Type sourceType,
com.android.dx.rop.type.Type targetType) {
if (sourceType.getBasicType() == BT_INT) {
switch (targetType.getBasicType()) {
case BT_SHORT:
return Rops.TO_SHORT;
case BT_CHAR:
return Rops.TO_CHAR;
case BT_BYTE:
return Rops.TO_BYTE;
}
}
return Rops.opConv(targetType, sourceType);
}
// instructions: arrays
/**
* Sets {@code target} to the length of the array in {@code array}.
*/
public <T> void arrayLength(Local<Integer> target, Local<T> array) {
addInstruction(new ThrowingInsn(Rops.ARRAY_LENGTH, sourcePosition,
RegisterSpecList.make(array.spec()), catches));
moveResult(target, true);
}
/**
* Assigns {@code target} to a newly allocated array of length {@code
* length}. The array's type is the same as {@code target}'s type.
*/
public <T> void newArray(Local<T> target, Local<Integer> length) {
addInstruction(new ThrowingCstInsn(Rops.opNewArray(target.type.ropType), sourcePosition,
RegisterSpecList.make(length.spec()), catches, target.type.constant));
moveResult(target, true);
}
/**
* Assigns the element at {@code index} in {@code array} to {@code target}.
*/
public void aget(Local<?> target, Local<?> array, Local<Integer> index) {
addInstruction(new ThrowingInsn(Rops.opAget(target.type.ropType), sourcePosition,
RegisterSpecList.make(array.spec(), index.spec()), catches));
moveResult(target, true);
}
/**
* Assigns {@code source} to the element at {@code index} in {@code array}.
*/
public void aput(Local<?> array, Local<Integer> index, Local<?> source) {
addInstruction(new ThrowingInsn(Rops.opAput(source.type.ropType), sourcePosition,
RegisterSpecList.make(source.spec(), array.spec(), index.spec()), catches));
}
// instructions: return
/**
* Returns from a {@code void} method. After a return it is an error to
* define further instructions after a return without first {@link #mark
* marking} an existing unmarked label.
*/
public void returnVoid() {
if (!method.returnType.equals(TypeId.VOID)) {
throw new IllegalArgumentException("declared " + method.returnType
+ " but returned void");
}
addInstruction(new PlainInsn(Rops.RETURN_VOID, sourcePosition, null,
RegisterSpecList.EMPTY));
}
/**
* Returns the value in {@code result} to the calling method. After a return
* it is an error to define further instructions after a return without
* first {@link #mark marking} an existing unmarked label.
*/
public void returnValue(Local<?> result) {
if (!result.type.equals(method.returnType)) {
// TODO: this is probably too strict.
throw new IllegalArgumentException("declared " + method.returnType
+ " but returned " + result.type);
}
addInstruction(new PlainInsn(Rops.opReturn(result.type.ropType), sourcePosition,
null, RegisterSpecList.make(result.spec())));
}
private void moveResult(Local<?> target, boolean afterNonInvokeThrowingInsn) {
Rop rop = afterNonInvokeThrowingInsn
? Rops.opMoveResultPseudo(target.type.ropType)
: Rops.opMoveResult(target.type.ropType);
addInstruction(new PlainInsn(rop, sourcePosition, target.spec(), RegisterSpecList.EMPTY));
}
// instructions; synchronized
/**
* Awaits the lock on {@code monitor}, and acquires it.
*/
public void monitorEnter(Local<?> monitor) {
addInstruction(new ThrowingInsn(Rops.MONITOR_ENTER, sourcePosition,
RegisterSpecList.make(monitor.spec()), catches));
}
/**
* Releases the held lock on {@code monitor}.
*/
public void monitorExit(Local<?> monitor) {
addInstruction(new ThrowingInsn(Rops.MONITOR_EXIT, sourcePosition,
RegisterSpecList.make(monitor.spec()), catches));
}
// produce BasicBlocks for dex
BasicBlockList toBasicBlocks() {
if (!localsInitialized) {
initializeLocals();
}
cleanUpLabels();
BasicBlockList result = new BasicBlockList(labels.size());
for (int i = 0; i < labels.size(); i++) {
result.set(i, labels.get(i).toBasicBlock());
}
return result;
}
/**
* Removes empty labels and assigns IDs to non-empty labels.
*/
private void cleanUpLabels() {
int id = 0;
for (Iterator<Label> i = labels.iterator(); i.hasNext();) {
Label label = i.next();
if (label.isEmpty()) {
i.remove();
} else {
label.compact();
label.id = id++;
}
}
}
private static RegisterSpecList concatenate(Local<?> first, Local<?>[] rest) {
int offset = (first != null) ? 1 : 0;
RegisterSpecList result = new RegisterSpecList(offset + rest.length);
if (first != null) {
result.set(0, first.spec());
}
for (int i = 0; i < rest.length; i++) {
result.set(i + offset, rest[i].spec());
}
return result;
}
}