Java example source code file (Instruction.java)
The Instruction.java Java example source code
/*
* Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.tools.asm;
import sun.tools.java.*;
import java.util.Enumeration;
import java.io.IOException;
import java.io.DataOutputStream;
/**
* An Java instruction
*
* WARNING: The contents of this source file are not part of any
* supported API. Code that depends on them does so at its own risk:
* they are subject to change or removal without notice.
*/
public
class Instruction implements Constants {
long where;
int pc;
int opc;
Object value;
Instruction next;
//JCOV
boolean flagCondInverted; /* if true, the condition is reversed
relatively of source code */
boolean flagNoCovered = false; /* if true, the command will
ignored for coverage */
/**
* Constructor
*/
public Instruction(long where, int opc, Object value, boolean flagCondInverted) {
this.where = where;
this.opc = opc;
this.value = value;
this.flagCondInverted = flagCondInverted;
}
/**
* Constructor
*/
public Instruction(boolean flagNoCovered, long where, int opc, Object value) {
this.where = where;
this.opc = opc;
this.value = value;
this.flagNoCovered = flagNoCovered;
}
/**
* Constructor
*/
public Instruction(long where, int opc, boolean flagNoCovered) {
this.where = where;
this.opc = opc;
this.flagNoCovered = flagNoCovered;
}
//end JCOV
/**
* Constructor
*/
public Instruction(long where, int opc, Object value) {
this.where = where;
this.opc = opc;
this.value = value;
}
/**
* When deciding between a lookupswitch and a tableswitch, this
* value is used in determining how much size increase is
* acceptable.
*/
public static final double SWITCHRATIO;
static {
// Set SWITCHRATIO from the property javac.switchratio
// if it exists and is reasonable. Otherwise, set
// SWITCHRATIO to 1.5, meaning that we will accept a 1.5x
// blowup (for the instruction) to use a tableswitch instead
// of a lookupswitch.
double ratio = 1.5;
String valStr = System.getProperty("javac.switchratio");
if (valStr != null) {
try {
double temp = Double.valueOf(valStr).doubleValue();
if (!(Double.isNaN(temp) || temp < 0.0)) {
ratio = temp;
}
} catch (NumberFormatException ee) {}
}
SWITCHRATIO = ratio;
}
/**
* Accessor
*/
public int getOpcode() {
return pc;
}
public Object getValue() {
return value;
}
public void setValue(Object value) {
this.value = value;
}
/**
* Optimize
*/
void optimize(Environment env) {
switch (opc) {
case opc_istore: case opc_lstore: case opc_fstore:
case opc_dstore: case opc_astore:
// Don't keep the LocalVariable info around, unless we
// are actually going to generate a local variable table.
if ((value instanceof LocalVariable) && !env.debug_vars()) {
value = new Integer(((LocalVariable)value).slot);
}
break;
case opc_goto: {
Label lbl = (Label)value;
value = lbl = lbl.getDestination();
if (lbl == next) {
// goto to the next instruction, obsolete
opc = opc_dead;
break;
}
// We optimize
//
// goto Tag
// ...
// Tag:
// return
//
// except when we're generating debuggable code. When
// we're generating debuggable code, we leave it alone,
// in order to provide better stepping behavior. Consider
// a method the end of which looks like this:
//
// ...
// break;
// } // end of loop
// } // end of method
//
// If we optimize the goto away, we'll be left with a
// single instruction (return) and the need to ascribe that
// instruction to two source lines (the break statement and
// the method's right curly). Can't get there from here.
// Depending on which line-number ascription we choose, the
// stepping user will step directly from the break statement
// back into the caller of the method (case 1) or from the
// statement that precedes the break statement to the method's
// right curly (case 2). Similarly, he'll be able to set a
// breakpoint on the break statement (case 1) or the method's
// right curly (case 2), but not on both. Neither case 1 nor
// case 2 is desirable. .We want him to see both the break
// statement and the method's right curly when stepping,
// and we want him to be able to set a breakpoint on either or
// both. So we suppress the optimization when generating
// debuggable code.
// (Above notes from brucek@eng in JDK1.0.2, copied here
// by kelly.ohair@eng for JDK1.1)
//
// With the changes to allow -O and -g at the same time,
// I've changed the condition to be whether optimization is
// on instead of the debugging flag being off.
// - david.stoutamire@eng for 1.2
if (lbl.next != null && env.opt()) {
switch (lbl.next.opc) {
case opc_return: case opc_ireturn: case opc_lreturn:
case opc_freturn: case opc_dreturn: case opc_areturn:
// goto to return
opc = lbl.next.opc;
value = lbl.next.value;
break;
}
}
break;
}
case opc_ifeq: case opc_ifne: case opc_ifgt:
case opc_ifge: case opc_iflt: case opc_ifle:
case opc_ifnull: case opc_ifnonnull:
value = ((Label)value).getDestination();
if (value == next) {
// branch to next instruction, obsolete
opc = opc_pop;
break;
}
if ((next.opc == opc_goto) && (value == next.next)) {
// Conditional branch over goto, invert
// Note that you can't invert all conditions, condition
// results for float/double compares are not invertable.
switch (opc) {
case opc_ifeq: opc = opc_ifne; break;
case opc_ifne: opc = opc_ifeq; break;
case opc_iflt: opc = opc_ifge; break;
case opc_ifle: opc = opc_ifgt; break;
case opc_ifgt: opc = opc_ifle; break;
case opc_ifge: opc = opc_iflt; break;
case opc_ifnull: opc = opc_ifnonnull; break;
case opc_ifnonnull: opc = opc_ifnull; break;
}
//JCOV
flagCondInverted = !flagCondInverted;
//end JCOV
value = next.value;
next.opc = opc_dead;
}
break;
case opc_if_acmpeq: case opc_if_acmpne:
case opc_if_icmpeq: case opc_if_icmpne:
case opc_if_icmpgt: case opc_if_icmpge:
case opc_if_icmplt: case opc_if_icmple:
value = ((Label)value).getDestination();
if (value == next) {
// branch to next instruction, obsolete
opc = opc_pop2;
break;
}
if ((next.opc == opc_goto) && (value == next.next)) {
// Conditional branch over goto, invert
switch (opc) {
case opc_if_acmpeq: opc = opc_if_acmpne; break;
case opc_if_acmpne: opc = opc_if_acmpeq; break;
case opc_if_icmpeq: opc = opc_if_icmpne; break;
case opc_if_icmpne: opc = opc_if_icmpeq; break;
case opc_if_icmpgt: opc = opc_if_icmple; break;
case opc_if_icmpge: opc = opc_if_icmplt; break;
case opc_if_icmplt: opc = opc_if_icmpge; break;
case opc_if_icmple: opc = opc_if_icmpgt; break;
}
//JCOV
flagCondInverted = !flagCondInverted;
//end JCOV
value = next.value;
next.opc = opc_dead;
}
break;
case opc_tableswitch:
case opc_lookupswitch: {
SwitchData sw = (SwitchData)value;
sw.defaultLabel = sw.defaultLabel.getDestination();
for (Enumeration<Integer> e = sw.tab.keys() ; e.hasMoreElements() ; ) {
Integer k = e.nextElement();
Label lbl = sw.tab.get(k);
sw.tab.put(k, lbl.getDestination());
}
// Compute the approximate sizes of a tableswitch and a
// lookupswitch. Decide which one we want to generate.
long range = (long)sw.maxValue - (long)sw.minValue + 1;
long entries = sw.tab.size();
long tableSize = 4 + range;
long lookupSize = 3 + 2 * entries;
if (tableSize <= lookupSize * SWITCHRATIO) {
opc = opc_tableswitch;
} else {
opc = opc_lookupswitch;
}
break;
}
}
}
/**
* Collect constants into the constant table
*/
void collect(ConstantPool tab) {
switch (opc) {
case opc_istore: case opc_lstore: case opc_fstore:
case opc_dstore: case opc_astore:
if (value instanceof LocalVariable) {
MemberDefinition field = ((LocalVariable)value).field;
tab.put(field.getName().toString());
tab.put(field.getType().getTypeSignature());
}
return;
case opc_new: case opc_putfield:
case opc_putstatic: case opc_getfield:
case opc_getstatic: case opc_invokevirtual:
case opc_invokespecial: case opc_invokestatic:
case opc_invokeinterface: case opc_instanceof:
case opc_checkcast:
tab.put(value);
return;
case opc_anewarray:
tab.put(value);
return;
case opc_multianewarray:
tab.put(((ArrayData)value).type);
return;
case opc_ldc:
case opc_ldc_w:
if (value instanceof Integer) {
int v = ((Integer)value).intValue();
if ((v >= -1) && (v <= 5)) {
opc = opc_iconst_0 + v;
return;
} else if ((v >= -(1 << 7)) && (v < (1 << 7))) {
opc = opc_bipush;
return;
} else if ((v >= -(1 << 15)) && (v < (1 << 15))) {
opc = opc_sipush;
return;
}
} else if (value instanceof Float) {
float v = ((Float)value).floatValue();
if (v == 0) {
if (Float.floatToIntBits(v) == 0) {
opc = opc_fconst_0;
return;
}
} else if (v == 1) {
opc = opc_fconst_1;
return;
} else if (v == 2) {
opc = opc_fconst_2;
return;
}
}
tab.put(value);
return;
case opc_ldc2_w:
if (value instanceof Long) {
long v = ((Long)value).longValue();
if (v == 0) {
opc = opc_lconst_0;
return;
} else if (v == 1) {
opc = opc_lconst_1;
return;
}
} else if (value instanceof Double) {
double v = ((Double)value).doubleValue();
if (v == 0) {
if (Double.doubleToLongBits(v) == 0) {
opc = opc_dconst_0;
return;
}
} else if (v == 1) {
opc = opc_dconst_1;
return;
}
}
tab.put(value);
return;
case opc_try:
for (Enumeration<CatchData> e = ((TryData)value).catches.elements() ; e.hasMoreElements() ;) {
CatchData cd = e.nextElement();
if (cd.getType() != null) {
tab.put(cd.getType());
}
}
return;
case opc_nop:
if ((value != null) && (value instanceof ClassDeclaration))
tab.put(value);
return;
}
}
/**
* Balance the stack
*/
int balance() {
switch (opc) {
case opc_dead: case opc_label: case opc_iinc:
case opc_arraylength: case opc_laload: case opc_daload:
case opc_nop: case opc_ineg: case opc_fneg:
case opc_lneg: case opc_dneg: case opc_i2f:
case opc_f2i: case opc_l2d: case opc_d2l:
case opc_i2b: case opc_i2c: case opc_i2s:
case opc_jsr: case opc_goto: case opc_jsr_w:
case opc_goto_w: case opc_return: case opc_ret:
case opc_instanceof: case opc_checkcast: case opc_newarray:
case opc_anewarray: case opc_try: case opc_swap:
return 0;
case opc_ldc: case opc_ldc_w: case opc_bipush:
case opc_sipush: case opc_aconst_null: case opc_iconst_m1:
case opc_iconst_0: case opc_iconst_1: case opc_iconst_2:
case opc_iconst_3: case opc_iconst_4: case opc_iconst_5:
case opc_fconst_0: case opc_fconst_1: case opc_fconst_2:
case opc_iload: case opc_fload: case opc_aload:
case opc_dup: case opc_dup_x1: case opc_dup_x2:
case opc_i2l: case opc_i2d: case opc_f2l:
case opc_f2d: case opc_new:
return 1;
case opc_lload: case opc_dload: case opc_dup2:
case opc_dup2_x1: case opc_dup2_x2: case opc_ldc2_w:
case opc_lconst_0: case opc_lconst_1: case opc_dconst_0:
case opc_dconst_1:
return 2;
case opc_istore: case opc_fstore: case opc_astore:
case opc_iaload: case opc_faload: case opc_aaload:
case opc_baload: case opc_caload: case opc_saload:
case opc_pop: case opc_iadd: case opc_fadd:
case opc_isub: case opc_fsub: case opc_imul:
case opc_fmul: case opc_idiv: case opc_fdiv:
case opc_irem: case opc_frem: case opc_ishl:
case opc_ishr: case opc_iushr: case opc_lshl:
case opc_lshr: case opc_lushr: case opc_iand:
case opc_ior: case opc_ixor: case opc_l2i:
case opc_l2f: case opc_d2i: case opc_d2f:
case opc_ifeq: case opc_ifne: case opc_iflt:
case opc_ifle: case opc_ifgt: case opc_ifge:
case opc_ifnull: case opc_ifnonnull: case opc_fcmpl:
case opc_fcmpg: case opc_ireturn: case opc_freturn:
case opc_areturn: case opc_tableswitch: case opc_lookupswitch:
case opc_athrow: case opc_monitorenter: case opc_monitorexit:
return -1;
case opc_lstore: case opc_dstore: case opc_pop2:
case opc_ladd: case opc_dadd: case opc_lsub:
case opc_dsub: case opc_lmul: case opc_dmul:
case opc_ldiv: case opc_ddiv: case opc_lrem:
case opc_drem: case opc_land: case opc_lor:
case opc_lxor: case opc_if_acmpeq: case opc_if_acmpne:
case opc_if_icmpeq: case opc_if_icmpne: case opc_if_icmplt:
case opc_if_icmple: case opc_if_icmpgt: case opc_if_icmpge:
case opc_lreturn: case opc_dreturn:
return -2;
case opc_iastore: case opc_fastore: case opc_aastore:
case opc_bastore: case opc_castore: case opc_sastore:
case opc_lcmp: case opc_dcmpl: case opc_dcmpg:
return -3;
case opc_lastore: case opc_dastore:
return -4;
case opc_multianewarray:
return 1 - ((ArrayData)value).nargs;
case opc_getfield:
return ((MemberDefinition)value).getType().stackSize() - 1;
case opc_putfield:
return -1 - ((MemberDefinition)value).getType().stackSize();
case opc_getstatic:
return ((MemberDefinition)value).getType().stackSize();
case opc_putstatic:
return -((MemberDefinition)value).getType().stackSize();
case opc_invokevirtual:
case opc_invokespecial:
case opc_invokeinterface:
return ((MemberDefinition)value).getType().getReturnType().stackSize() -
(((MemberDefinition)value).getType().stackSize() + 1);
case opc_invokestatic:
return ((MemberDefinition)value).getType().getReturnType().stackSize() -
(((MemberDefinition)value).getType().stackSize());
}
throw new CompilerError("invalid opcode: " + toString());
}
/**
* Return the size of the instruction
*/
int size(ConstantPool tab) {
switch (opc) {
case opc_try: case opc_label: case opc_dead:
return 0;
case opc_bipush: case opc_newarray:
return 2;
case opc_sipush: case opc_goto: case opc_jsr:
case opc_ifeq: case opc_ifne: case opc_ifgt:
case opc_ifge: case opc_iflt: case opc_ifle:
case opc_ifnull: case opc_ifnonnull: case opc_if_acmpeq:
case opc_if_acmpne: case opc_if_icmpeq: case opc_if_icmpne:
case opc_if_icmpgt: case opc_if_icmpge: case opc_if_icmplt:
case opc_if_icmple:
return 3;
case opc_ldc:
case opc_ldc_w:
if (tab.index(value) < 256) {
opc = opc_ldc;
return 2;
} else {
opc = opc_ldc_w;
return 3;
}
case opc_iload: case opc_lload: case opc_fload:
case opc_dload: case opc_aload: {
int v = ((Number)value).intValue();
if (v < 4) {
if (v < 0) {
throw new CompilerError("invalid slot: " + toString()
+ "\nThis error possibly resulted from poorly constructed class paths.");
}
opc = opc_iload_0 + (opc - opc_iload) * 4 + v;
return 1;
} else if (v <= 255) {
return 2;
} else {
opc += 256; // indicate wide variant
return 4;
}
}
case opc_iinc: {
int register = ((int[])value)[0];
int increment = ((int[])value)[1];
if (register < 0) {
throw new CompilerError("invalid slot: " + toString());
}
if (register <= 255 && (((byte)increment) == increment)) {
return 3;
} else {
opc += 256; // indicate wide variant
return 6;
}
}
case opc_istore: case opc_lstore: case opc_fstore:
case opc_dstore: case opc_astore: {
int v = (value instanceof Number) ?
((Number)value).intValue() : ((LocalVariable)value).slot;
if (v < 4) {
if (v < 0) {
throw new CompilerError("invalid slot: " + toString());
}
opc = opc_istore_0 + (opc - opc_istore) * 4 + v;
return 1;
} else if (v <= 255) {
return 2;
} else {
opc += 256; // indicate wide variant
return 4;
}
}
case opc_ret: {
int v = ((Number)value).intValue();
if (v <= 255) {
if (v < 0) {
throw new CompilerError("invalid slot: " + toString());
}
return 2;
} else {
opc += 256; // indicate wide variant
return 4;
}
}
case opc_ldc2_w: case opc_new:
case opc_putstatic: case opc_getstatic:
case opc_putfield: case opc_getfield:
case opc_invokevirtual: case opc_invokespecial:
case opc_invokestatic: case opc_instanceof:
case opc_checkcast: case opc_anewarray:
return 3;
case opc_multianewarray:
return 4;
case opc_invokeinterface:
case opc_goto_w:
case opc_jsr_w:
return 5;
case opc_tableswitch: {
SwitchData sw = (SwitchData)value;
int n = 1;
for(; ((pc + n) % 4) != 0 ; n++);
return n + 16 + (sw.maxValue - sw.minValue) * 4;
}
case opc_lookupswitch: {
SwitchData sw = (SwitchData)value;
int n = 1;
for(; ((pc + n) % 4) != 0 ; n++);
return n + 8 + sw.tab.size() * 8;
}
case opc_nop:
if ((value != null) && !(value instanceof Integer))
return 2;
else
return 1;
}
// most opcodes are only 1 byte long
return 1;
}
/**
* Generate code
*/
@SuppressWarnings("fallthrough")
void write(DataOutputStream out, ConstantPool tab) throws IOException {
switch (opc) {
case opc_try: case opc_label: case opc_dead:
break;
case opc_bipush: case opc_newarray:
case opc_iload: case opc_lload: case opc_fload:
case opc_dload: case opc_aload: case opc_ret:
out.writeByte(opc);
out.writeByte(((Number)value).intValue());
break;
case opc_iload + 256: case opc_lload + 256:
case opc_fload + 256: case opc_dload + 256:
case opc_aload + 256: case opc_ret + 256:
out.writeByte(opc_wide);
out.writeByte(opc - 256);
out.writeShort(((Number)value).intValue());
break;
case opc_istore: case opc_lstore: case opc_fstore:
case opc_dstore: case opc_astore:
out.writeByte(opc);
out.writeByte((value instanceof Number) ?
((Number)value).intValue() : ((LocalVariable)value).slot);
break;
case opc_istore + 256: case opc_lstore + 256:
case opc_fstore + 256: case opc_dstore + 256:
case opc_astore + 256:
out.writeByte(opc_wide);
out.writeByte(opc - 256);
out.writeShort((value instanceof Number) ?
((Number)value).intValue() : ((LocalVariable)value).slot);
break;
case opc_sipush:
out.writeByte(opc);
out.writeShort(((Number)value).intValue());
break;
case opc_ldc:
out.writeByte(opc);
out.writeByte(tab.index(value));
break;
case opc_ldc_w: case opc_ldc2_w:
case opc_new: case opc_putstatic:
case opc_getstatic: case opc_putfield:
case opc_getfield: case opc_invokevirtual:
case opc_invokespecial: case opc_invokestatic:
case opc_instanceof: case opc_checkcast:
out.writeByte(opc);
out.writeShort(tab.index(value));
break;
case opc_iinc:
out.writeByte(opc);
out.writeByte(((int[])value)[0]); // register
out.writeByte(((int[])value)[1]); // increment
break;
case opc_iinc + 256:
out.writeByte(opc_wide);
out.writeByte(opc - 256);
out.writeShort(((int[])value)[0]); // register
out.writeShort(((int[])value)[1]); // increment
break;
case opc_anewarray:
out.writeByte(opc);
out.writeShort(tab.index(value));
break;
case opc_multianewarray:
out.writeByte(opc);
out.writeShort(tab.index(((ArrayData)value).type));
out.writeByte(((ArrayData)value).nargs);
break;
case opc_invokeinterface:
out.writeByte(opc);
out.writeShort(tab.index(value));
out.writeByte(((MemberDefinition)value).getType().stackSize() + 1);
out.writeByte(0);
break;
case opc_goto: case opc_jsr: case opc_ifeq:
case opc_ifne: case opc_ifgt: case opc_ifge:
case opc_iflt: case opc_ifle: case opc_ifnull:
case opc_ifnonnull: case opc_if_acmpeq: case opc_if_acmpne:
case opc_if_icmpeq: case opc_if_icmpne: case opc_if_icmpgt:
case opc_if_icmpge: case opc_if_icmplt: case opc_if_icmple:
out.writeByte(opc);
out.writeShort(((Instruction)value).pc - pc);
break;
case opc_goto_w:
case opc_jsr_w:
out.writeByte(opc);
out.writeLong(((Instruction)value).pc - pc);
break;
case opc_tableswitch: {
SwitchData sw = (SwitchData)value;
out.writeByte(opc);
for(int n = 1 ; ((pc + n) % 4) != 0 ; n++) {
out.writeByte(0);
}
out.writeInt(sw.defaultLabel.pc - pc);
out.writeInt(sw.minValue);
out.writeInt(sw.maxValue);
for (int n = sw.minValue ; n <= sw.maxValue ; n++) {
Label lbl = sw.get(n);
int target_pc = (lbl != null) ? lbl.pc : sw.defaultLabel.pc;
out.writeInt(target_pc - pc);
}
break;
}
case opc_lookupswitch: {
SwitchData sw = (SwitchData)value;
out.writeByte(opc);
int n = pc + 1;
for(; (n % 4) != 0 ; n++) {
out.writeByte(0);
}
out.writeInt(sw.defaultLabel.pc - pc);
out.writeInt(sw.tab.size());
for (Enumeration<Integer> e = sw.sortedKeys(); e.hasMoreElements() ; ) {
Integer v = e.nextElement();
out.writeInt(v.intValue());
out.writeInt(sw.get(v).pc - pc);
}
break;
}
case opc_nop:
if (value != null) {
if (value instanceof Integer)
out.writeByte(((Integer)value).intValue());
else
out.writeShort(tab.index(value));
return;
}
// fall through
default:
out.writeByte(opc);
break;
}
}
/**
* toString
*/
public String toString() {
String prefix = (where >> WHEREOFFSETBITS) + ":\t";
switch (opc) {
case opc_try:
return prefix + "try " + ((TryData)value).getEndLabel().hashCode();
case opc_dead:
return prefix + "dead";
case opc_iinc: {
int register = ((int[])value)[0];
int increment = ((int[])value)[1];
return prefix + opcNames[opc] + " " + register + ", " + increment;
}
default:
if (value != null) {
if (value instanceof Label) {
return prefix + opcNames[opc] + " " + value.toString();
} else if (value instanceof Instruction) {
return prefix + opcNames[opc] + " " + value.hashCode();
} else if (value instanceof String) {
return prefix + opcNames[opc] + " \"" + value + "\"";
} else {
return prefix + opcNames[opc] + " " + value;
}
} else {
return prefix + opcNames[opc];
}
}
}
}
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