/*
* Copyright (C) 2007 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.dex.code;
import com.android.dx.rop.code.RegisterSpecList;
import com.android.dx.rop.cst.Constant;
import com.android.dx.rop.cst.CstInteger;
import com.android.dx.rop.cst.CstKnownNull;
import com.android.dx.rop.cst.CstLiteral64;
import com.android.dx.rop.cst.CstLiteralBits;
import com.android.dx.util.AnnotatedOutput;
import com.android.dx.util.Hex;
/**
* Base class for all instruction format handlers. Instruction format
* handlers know how to translate {@link DalvInsn} instances into
* streams of code words, as well as human-oriented listing strings
* representing such translations.
*/
public abstract class InsnFormat {
/**
* Returns the string form, suitable for inclusion in a listing
* dump, of the given instruction. The instruction must be of this
* instance's format for proper operation.
*
* @param insn non-null; the instruction
* @param noteIndices whether to include an explicit notation of
* constant pool indices
* @return non-null; the string form
*/
public final String listingString(DalvInsn insn, boolean noteIndices) {
String op = insn.getOpcode().getName();
String arg = insnArgString(insn);
String comment = insnCommentString(insn, noteIndices);
StringBuilder sb = new StringBuilder(100);
sb.append(op);
if (arg.length() != 0) {
sb.append(' ');
sb.append(arg);
}
if (comment.length() != 0) {
sb.append(" // ");
sb.append(comment);
}
return sb.toString();
}
/**
* Returns the string form of the arguments to the given instruction.
* The instruction must be of this instance's format. If the instruction
* has no arguments, then the result should be <code>""</code>, not
* <code>null</code>.
*
* <p>Subclasses must override this method.</p>
*
* @param insn non-null; the instruction
* @return non-null; the string form
*/
public abstract String insnArgString(DalvInsn insn);
/**
* Returns the associated comment for the given instruction, if any.
* The instruction must be of this instance's format. If the instruction
* has no comment, then the result should be <code>""</code>, not
* <code>null</code>.
*
* <p>Subclasses must override this method.</p>
*
* @param insn non-null; the instruction
* @param noteIndices whether to include an explicit notation of
* constant pool indices
* @return non-null; the string form
*/
public abstract String insnCommentString(DalvInsn insn,
boolean noteIndices);
/**
* Gets the code size of instructions that use this format. The
* size is a number of 16-bit code units, not bytes. This should
* throw an exception if this format is of variable size.
*
* @return >= 0; the instruction length in 16-bit code units
*/
public abstract int codeSize();
/**
* Returns whether or not the given instruction's arguments will
* fit in this instance's format. This includes such things as
* counting register arguments, checking register ranges, and
* making sure that additional arguments are of appropriate types
* and are in-range. If this format has a branch target but the
* instruction's branch offset is unknown, this method will simply
* not check the offset.
*
* <p>Subclasses must override this method.</p>
*
* @param insn non-null; the instruction to check
* @return <code>true</code> iff the instruction's arguments are
* appropriate for this instance, or <code>false</code> if not
*/
public abstract boolean isCompatible(DalvInsn insn);
/**
* Returns whether or not the given instruction's branch offset will
* fit in this instance's format. This always returns <code>false</code>
* for formats that don't include a branch offset.
*
* <p>The default implementation of this method always returns
* <code>false</code>. Subclasses must override this method if they
* include branch offsets.</p>
*
* @param insn non-null; the instruction to check
* @return <code>true</code> iff the instruction's branch offset is
* appropriate for this instance, or <code>false</code> if not
*/
public boolean branchFits(TargetInsn insn) {
return false;
}
/**
* Returns the next instruction format to try to match an instruction
* with, presuming that this instance isn't compatible, if any.
*
* <p>Subclasses must override this method.</p>
*
* @return null-ok; the next format to try, or <code>null</code> if
* there are no suitable alternatives
*/
public abstract InsnFormat nextUp();
/**
* Writes the code units for the given instruction to the given
* output destination. The instruction must be of this instance's format.
*
* <p>Subclasses must override this method.</p>
*
* @param out non-null; the output destination to write to
* @param insn non-null; the instruction to write
*/
public abstract void writeTo(AnnotatedOutput out, DalvInsn insn);
/**
* Helper method to return a register list string.
*
* @param list non-null; the list of registers
* @return non-null; the string form
*/
protected static String regListString(RegisterSpecList list) {
int sz = list.size();
StringBuffer sb = new StringBuffer(sz * 5 + 2);
sb.append('{');
for (int i = 0; i < sz; i++) {
if (i != 0) {
sb.append(", ");
}
sb.append(list.get(i).regString());
}
sb.append('}');
return sb.toString();
}
/**
* Helper method to return a literal bits argument string.
*
* @param value the value
* @return non-null; the string form
*/
protected static String literalBitsString(CstLiteralBits value) {
StringBuffer sb = new StringBuffer(100);
sb.append('#');
if (value instanceof CstKnownNull) {
sb.append("null");
} else {
sb.append(value.typeName());
sb.append(' ');
sb.append(value.toHuman());
}
return sb.toString();
}
/**
* Helper method to return a literal bits comment string.
*
* @param value the value
* @param width the width of the constant, in bits (used for displaying
* the uninterpreted bits; one of: <code>4 8 16 32 64</code>
* @return non-null; the comment
*/
protected static String literalBitsComment(CstLiteralBits value,
int width) {
StringBuffer sb = new StringBuffer(20);
sb.append("#");
long bits;
if (value instanceof CstLiteral64) {
bits = ((CstLiteral64) value).getLongBits();
} else {
bits = value.getIntBits();
}
switch (width) {
case 4: sb.append(Hex.uNibble((int) bits)); break;
case 8: sb.append(Hex.u1((int) bits)); break;
case 16: sb.append(Hex.u2((int) bits)); break;
case 32: sb.append(Hex.u4((int) bits)); break;
case 64: sb.append(Hex.u8(bits)); break;
default: {
throw new RuntimeException("shouldn't happen");
}
}
return sb.toString();
}
/**
* Helper method to return a branch address string.
*
* @param insn non-null; the instruction in question
* @return non-null; the string form of the instruction's branch target
*/
protected static String branchString(DalvInsn insn) {
TargetInsn ti = (TargetInsn) insn;
int address = ti.getTargetAddress();
return (address == (char) address) ? Hex.u2(address) : Hex.u4(address);
}
/**
* Helper method to return the comment for a branch.
*
* @param insn non-null; the instruction in question
* @return non-null; the comment
*/
protected static String branchComment(DalvInsn insn) {
TargetInsn ti = (TargetInsn) insn;
int offset = ti.getTargetOffset();
return (offset == (short) offset) ? Hex.s2(offset) : Hex.s4(offset);
}
/**
* Helper method to return a constant string.
*
* @param insn non-null; a constant-bearing instruction
* @return non-null; the string form of the contained constant
*/
protected static String cstString(DalvInsn insn) {
CstInsn ci = (CstInsn) insn;
Constant cst = ci.getConstant();
return cst.toHuman();
}
/**
* Helper method to return an instruction comment for a constant.
*
* @param insn non-null; a constant-bearing instruction
* @return non-null; comment string representing the constant
*/
protected static String cstComment(DalvInsn insn) {
CstInsn ci = (CstInsn) insn;
if (! ci.hasIndex()) {
return "";
}
StringBuilder sb = new StringBuilder(20);
int index = ci.getIndex();
sb.append(ci.getConstant().typeName());
sb.append('@');
if (index < 65536) {
sb.append(Hex.u2(index));
} else {
sb.append(Hex.u4(index));
}
return sb.toString();
}
/**
* Helper method to determine if a signed int value fits in a nibble.
*
* @param value the value in question
* @return <code>true</code> iff it's in the range -8..+7
*/
protected static boolean signedFitsInNibble(int value) {
return (value >= -8) && (value <= 7);
}
/**
* Helper method to determine if an unsigned int value fits in a nibble.
*
* @param value the value in question
* @return <code>true</code> iff it's in the range 0..0xf
*/
protected static boolean unsignedFitsInNibble(int value) {
return value == (value & 0xf);
}
/**
* Helper method to determine if a signed int value fits in a byte.
*
* @param value the value in question
* @return <code>true</code> iff it's in the range -0x80..+0x7f
*/
protected static boolean signedFitsInByte(int value) {
return (byte) value == value;
}
/**
* Helper method to determine if an unsigned int value fits in a byte.
*
* @param value the value in question
* @return <code>true</code> iff it's in the range 0..0xff
*/
protected static boolean unsignedFitsInByte(int value) {
return value == (value & 0xff);
}
/**
* Helper method to determine if a signed int value fits in a short.
*
* @param value the value in question
* @return <code>true</code> iff it's in the range -0x8000..+0x7fff
*/
protected static boolean signedFitsInShort(int value) {
return (short) value == value;
}
/**
* Helper method to determine if an unsigned int value fits in a short.
*
* @param value the value in question
* @return <code>true</code> iff it's in the range 0..0xffff
*/
protected static boolean unsignedFitsInShort(int value) {
return value == (value & 0xffff);
}
/**
* Helper method to determine if a signed int value fits in three bytes.
*
* @param value the value in question
* @return <code>true</code> iff it's in the range -0x800000..+0x7fffff
*/
protected static boolean signedFitsIn3Bytes(int value) {
return value == ((value << 8) >> 8);
}
/**
* Helper method to extract the callout-argument index from an
* appropriate instruction.
*
* @param insn non-null; the instruction
* @return >= 0; the callout argument index
*/
protected static int argIndex(DalvInsn insn) {
int arg = ((CstInteger) ((CstInsn) insn).getConstant()).getValue();
if (arg < 0) {
throw new IllegalArgumentException("bogus insn");
}
return arg;
}
/**
* Helper method to combine an opcode and a second byte of data into
* the appropriate form for emitting into a code buffer.
*
* @param insn non-null; the instruction containing the opcode
* @param arg 0..255; arbitrary other byte value
* @return combined value
*/
protected static short opcodeUnit(DalvInsn insn, int arg) {
if ((arg & 0xff) != arg) {
throw new IllegalArgumentException("arg out of range 0..255");
}
int opcode = insn.getOpcode().getOpcode();
if ((opcode & 0xff) != opcode) {
throw new IllegalArgumentException("opcode out of range 0..255");
}
return (short) (opcode | (arg << 8));
}
/**
* Helper method to combine two bytes into a code unit.
*
* @param low 0..255; low byte
* @param high 0..255; high byte
* @return combined value
*/
protected static short codeUnit(int low, int high) {
if ((low & 0xff) != low) {
throw new IllegalArgumentException("low out of range 0..255");
}
if ((high & 0xff) != high) {
throw new IllegalArgumentException("high out of range 0..255");
}
return (short) (low | (high << 8));
}
/**
* Helper method to combine four nibbles into a code unit.
*
* @param n0 0..15; low nibble
* @param n1 0..15; medium-low nibble
* @param n2 0..15; medium-high nibble
* @param n3 0..15; high nibble
* @return combined value
*/
protected static short codeUnit(int n0, int n1, int n2, int n3) {
if ((n0 & 0xf) != n0) {
throw new IllegalArgumentException("n0 out of range 0..15");
}
if ((n1 & 0xf) != n1) {
throw new IllegalArgumentException("n1 out of range 0..15");
}
if ((n2 & 0xf) != n2) {
throw new IllegalArgumentException("n2 out of range 0..15");
}
if ((n3 & 0xf) != n3) {
throw new IllegalArgumentException("n3 out of range 0..15");
}
return (short) (n0 | (n1 << 4) | (n2 << 8) | (n3 << 12));
}
/**
* Helper method to combine two nibbles into a byte.
*
* @param low 0..15; low nibble
* @param high 0..15; high nibble
* @return 0..255; combined value
*/
protected static int makeByte(int low, int high) {
if ((low & 0xf) != low) {
throw new IllegalArgumentException("low out of range 0..15");
}
if ((high & 0xf) != high) {
throw new IllegalArgumentException("high out of range 0..15");
}
return low | (high << 4);
}
/**
* Writes one code unit to the given output destination.
*
* @param out non-null; where to write to
* @param c0 code unit to write
*/
protected static void write(AnnotatedOutput out, short c0) {
out.writeShort(c0);
}
/**
* Writes two code units to the given output destination.
*
* @param out non-null; where to write to
* @param c0 code unit to write
* @param c1 code unit to write
*/
protected static void write(AnnotatedOutput out, short c0, short c1) {
out.writeShort(c0);
out.writeShort(c1);
}
/**
* Writes three code units to the given output destination.
*
* @param out non-null; where to write to
* @param c0 code unit to write
* @param c1 code unit to write
* @param c2 code unit to write
*/
protected static void write(AnnotatedOutput out, short c0, short c1,
short c2) {
out.writeShort(c0);
out.writeShort(c1);
out.writeShort(c2);
}
/**
* Writes four code units to the given output destination.
*
* @param out non-null; where to write to
* @param c0 code unit to write
* @param c1 code unit to write
* @param c2 code unit to write
* @param c3 code unit to write
*/
protected static void write(AnnotatedOutput out, short c0, short c1,
short c2, short c3) {
out.writeShort(c0);
out.writeShort(c1);
out.writeShort(c2);
out.writeShort(c3);
}
/**
* Writes five code units to the given output destination.
*
* @param out non-null; where to write to
* @param c0 code unit to write
* @param c1 code unit to write
* @param c2 code unit to write
* @param c3 code unit to write
* @param c4 code unit to write
*/
protected static void write(AnnotatedOutput out, short c0, short c1,
short c2, short c3, short c4) {
out.writeShort(c0);
out.writeShort(c1);
out.writeShort(c2);
out.writeShort(c3);
out.writeShort(c4);
}
/**
* Writes six code units to the given output destination.
*
* @param out non-null; where to write to
* @param c0 code unit to write
* @param c1 code unit to write
* @param c2 code unit to write
* @param c3 code unit to write
* @param c4 code unit to write
* @param c5 code unit to write
*/
protected static void write(AnnotatedOutput out, short c0, short c1,
short c2, short c3, short c4, short c5) {
out.writeShort(c0);
out.writeShort(c1);
out.writeShort(c2);
out.writeShort(c3);
out.writeShort(c4);
out.writeShort(c5);
}
}
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