/*
* @(#)Gen.java 1.148 07/03/21
*
* Copyright (c) 2007 Sun Microsystems, Inc. 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package com.sun.tools.javac.jvm;
import java.util.*;
import com.sun.tools.javac.util.*;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.code.*;
import com.sun.tools.javac.comp.*;
import com.sun.tools.javac.tree.*;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.code.Type.*;
import com.sun.tools.javac.jvm.Code.*;
import com.sun.tools.javac.jvm.Items.*;
import com.sun.tools.javac.tree.JCTree.*;
import static com.sun.tools.javac.code.Flags.*;
import static com.sun.tools.javac.code.Kinds.*;
import static com.sun.tools.javac.code.TypeTags.*;
import static com.sun.tools.javac.jvm.ByteCodes.*;
import static com.sun.tools.javac.jvm.CRTFlags.*;
/** This pass maps flat Java (i.e. without inner classes) to bytecodes.
*
* <p><b>This is NOT part of any API supported by Sun Microsystems. If
* you write code that depends on this, you do so at your own risk.
* This code and its internal interfaces are subject to change or
* deletion without notice.</b>
*/
@Version("@(#)Gen.java 1.148 07/03/21")
public class Gen extends JCTree.Visitor {
private static my.Debug DEBUG=new my.Debug(my.Debug.Gen);//我加上的
protected static final Context.Key<Gen> genKey =
new Context.Key<Gen>();
private final Log log;
private final Symtab syms;
private final Check chk;
private final Resolve rs;
private final TreeMaker make;
private final Name.Table names;
private final Target target;
private final Type stringBufferType;
private final Map<Type,Symbol> stringBufferAppend;
private Name accessDollar;
private final Types types;
/** Switch: GJ mode?
*/
private final boolean allowGenerics;
/** Set when Miranda method stubs are to be generated. */
private final boolean generateIproxies;
/** Format of stackmap tables to be generated. */
private final Code.StackMapFormat stackMap;
/** A type that serves as the expected type for all method expressions.
*/
private final Type methodType;
public static Gen instance(Context context) {
Gen instance = context.get(genKey);
if (instance == null)
instance = new Gen(context);
return instance;
}
protected Gen(Context context) {
DEBUG.P(this,"Gen(1)");
context.put(genKey, this);
names = Name.Table.instance(context);
log = Log.instance(context);
syms = Symtab.instance(context);
chk = Check.instance(context);
rs = Resolve.instance(context);
make = TreeMaker.instance(context);
target = Target.instance(context);
types = Types.instance(context);
methodType = new MethodType(null, null, null, syms.methodClass);
allowGenerics = Source.instance(context).allowGenerics();
stringBufferType = target.useStringBuilder()
? syms.stringBuilderType
: syms.stringBufferType;
stringBufferAppend = new HashMap<Type,Symbol>();
accessDollar = names.
fromString("access" + target.syntheticNameChar());
Options options = Options.instance(context);
lineDebugInfo =
options.get("-g:") == null ||
options.get("-g:lines") != null;
varDebugInfo =
options.get("-g:") == null
? options.get("-g") != null
: options.get("-g:vars") != null;
genCrt = options.get("-Xjcov") != null;
debugCode = options.get("debugcode") != null;
generateIproxies =
target.requiresIproxy() ||
options.get("miranda") != null;
if (target.generateStackMapTable()) {
// ignore cldc because we cannot have both stackmap formats
this.stackMap = StackMapFormat.JSR202;
} else {
if (target.generateCLDCStackmap()) {
this.stackMap = StackMapFormat.CLDC;
} else {
this.stackMap = StackMapFormat.NONE;
}
}
// by default, avoid jsr's for simple finalizers
int setjsrlimit = 50;
String jsrlimitString = options.get("jsrlimit");
if (jsrlimitString != null) {
try {
setjsrlimit = Integer.parseInt(jsrlimitString);
} catch (NumberFormatException ex) {
// ignore ill-formed numbers for jsrlimit
}
}
this.jsrlimit = setjsrlimit;
this.useJsrLocally = false; // reset in visitTry
DEBUG.P(0,this,"Gen(1)");
}
/** Switches
*/
private final boolean lineDebugInfo;
private final boolean varDebugInfo;
private final boolean genCrt;
private final boolean debugCode;
/** Default limit of (approximate) size of finalizer to inline.
* Zero means always use jsr. 100 or greater means never use
* jsr.
*/
private final int jsrlimit;
/** True if jsr is used.
*/
private boolean useJsrLocally;
/* Constant pool, reset by genClass.
*/
private Pool pool = new Pool();
/** Code buffer, set by genMethod.
*/
private Code code;
/** Items structure, set by genMethod.
*/
private Items items;
/** Environment for symbol lookup, set by genClass
*/
private Env<AttrContext> attrEnv;
/** The top level tree.
*/
private JCCompilationUnit toplevel;
/** The number of code-gen errors in this class.
*/
private int nerrs = 0;
/** A hash table mapping syntax trees to their ending source positions.
*/
private Map<JCTree, Integer> endPositions;
/** Generate code to load an integer constant.
* @param n The integer to be loaded.
*/
void loadIntConst(int n) {
DEBUG.P(this,"loadIntConst(1)");
DEBUG.P("n="+n);
items.makeImmediateItem(syms.intType, n).load();
DEBUG.P(0,this,"loadIntConst(1)");
}
/** The opcode that loads a zero constant of a given type code.
* @param tc The given type code (@see ByteCode).
*/
public static int zero(int tc) {
switch(tc) {
case INTcode: case BYTEcode: case SHORTcode: case CHARcode:
return iconst_0;
case LONGcode:
return lconst_0;
case FLOATcode:
return fconst_0;
case DOUBLEcode:
return dconst_0;
default:
throw new AssertionError("zero");
}
}
/** The opcode that loads a one constant of a given type code.
* @param tc The given type code (@see ByteCode).
*/
public static int one(int tc) {
return zero(tc) + 1;
}
/** Generate code to load -1 of the given type code (either int or long).
* @param tc The given type code (@see ByteCode).
*/
void emitMinusOne(int tc) {
if (tc == LONGcode) {
items.makeImmediateItem(syms.longType, new Long(-1)).load();
} else {
code.emitop0(iconst_m1);
}
}
/** Construct a symbol to reflect the qualifying type that should
* appear in the byte code as per JLS 13.1.
*
* For target >= 1.2: Clone a method with the qualifier as owner (except
* for those cases where we need to work around VM bugs).
*
* For target <= 1.1: If qualified variable or method is defined in a
* non-accessible class, clone it with the qualifier class as owner.
*
* @param sym The accessed symbol
* @param site The qualifier's type.
*/
Symbol binaryQualifier(Symbol sym, Type site) {
try {//我加上的
DEBUG.P(this,"binaryQualifier(Symbol sym, Type site)");
DEBUG.P("sym="+sym);
DEBUG.P("site="+site+" site.tag="+TypeTags.toString(site.tag));
if (site.tag == ARRAY) {
if (sym == syms.lengthVar ||
sym.owner != syms.arrayClass)
return sym;
// array clone can be qualified by the array type in later targets
Symbol qualifier = target.arrayBinaryCompatibility()
? new ClassSymbol(Flags.PUBLIC, site.tsym.name,
site, syms.noSymbol)
: syms.objectType.tsym;
return sym.clone(qualifier);
}
DEBUG.P("");
DEBUG.P("sym.owner="+sym.owner);
DEBUG.P("site.tsym="+site.tsym);
DEBUG.P("sym.flags()="+Flags.toString(sym.flags()));
if (sym.owner == site.tsym ||
(sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) {
return sym;
}
DEBUG.P("");
DEBUG.P("target.obeyBinaryCompatibility()="+target.obeyBinaryCompatibility());
if (!target.obeyBinaryCompatibility())
return rs.isAccessible(attrEnv, (TypeSymbol)sym.owner)
? sym
: sym.clone(site.tsym);
DEBUG.P("");
DEBUG.P("target.interfaceFieldsBinaryCompatibility()="+target.interfaceFieldsBinaryCompatibility());
if (!target.interfaceFieldsBinaryCompatibility()) {
if ((sym.owner.flags() & INTERFACE) != 0 && sym.kind == VAR)
return sym;
}
// leave alone methods inherited from Object
// JLS2 13.1.
if (sym.owner == syms.objectType.tsym)
return sym;
DEBUG.P("");
DEBUG.P("target.interfaceObjectOverridesBinaryCompatibility()="+target.interfaceObjectOverridesBinaryCompatibility());
if (!target.interfaceObjectOverridesBinaryCompatibility()) {
if ((sym.owner.flags() & INTERFACE) != 0 &&
syms.objectType.tsym.members().lookup(sym.name).scope != null)
return sym;
}
return sym.clone(site.tsym);
}finally{//我加上的
DEBUG.P(0,this,"binaryQualifier(Symbol sym, Type site)");
}
}
/** Insert a reference to given type in the constant pool,
* checking for an array with too many dimensions;
* return the reference's index.
* @param type The type for which a reference is inserted.
*/
int makeRef(DiagnosticPosition pos, Type type) {
try {//我加上的
DEBUG.P(this,"makeRef(2)");
DEBUG.P("type="+type+" type.tag="+TypeTags.toString(type.tag));
checkDimension(pos, type);
return pool.put(type.tag == CLASS ? (Object)type.tsym : (Object)type);
}finally{//我加上的
DEBUG.P(0,this,"makeRef(2)");
}
}
/** Check if the given type is an array with too many dimensions.
*/
private void checkDimension(DiagnosticPosition pos, Type t) {
switch (t.tag) {
case METHOD:
checkDimension(pos, t.getReturnType());
for (List<Type> args = t.getParameterTypes(); args.nonEmpty(); args = args.tail)
checkDimension(pos, args.head);
break;
case ARRAY:
//数组维数不能大于ClassFile.MAX_DIMENSIONS(255)
if (types.dimensions(t) > ClassFile.MAX_DIMENSIONS) {
log.error(pos, "limit.dimensions");
nerrs++;
}
break;
default:
break;
}
}
/** Create a tempory variable.
* @param type The variable's type.
*/
LocalItem makeTemp(Type type) {
try {//我加上的
DEBUG.P(this,"makeTemp(1)");
DEBUG.P("type="+type);
VarSymbol v = new VarSymbol(Flags.SYNTHETIC,
names.empty,
type,
env.enclMethod.sym);
code.newLocal(v);
return items.makeLocalItem(v);
}finally{//我加上的
DEBUG.P(0,this,"makeTemp(1)");
}
}
/** Generate code to call a non-private method or constructor.
* @param pos Position to be used for error reporting.
* @param site The type of which the method is a member.
* @param name The method's name.
* @param argtypes The method's argument types.
* @param isStatic A flag that indicates whether we call a
* static or instance method.
*/
void callMethod(DiagnosticPosition pos,
Type site, Name name, List<Type> argtypes,
boolean isStatic) {
DEBUG.P(this,"callMethod(4)");
DEBUG.P("site="+site);
DEBUG.P("name="+name);
DEBUG.P("argtypes="+argtypes);
DEBUG.P("isStatic="+isStatic);
Symbol msym = rs.
resolveInternalMethod(pos, attrEnv, site, name, argtypes, null);
if (isStatic) items.makeStaticItem(msym).invoke();
else items.makeMemberItem(msym, name == names.init).invoke();
DEBUG.P(0,this,"callMethod(4)");
}
/** Is the given method definition an access method
* resulting from a qualified super? This is signified by an odd
* access code.
*/
private boolean isAccessSuper(JCMethodDecl enclMethod) {
return
(enclMethod.mods.flags & SYNTHETIC) != 0 &&
isOddAccessName(enclMethod.name);
}
/** Does given name start with "access$" and end in an odd digit?
*/
private boolean isOddAccessName(Name name) {
//name的最后一个byte与1进行“按位与”运算后如果等于1就是一个基数
return
name.startsWith(accessDollar) &&
(name.byteAt(name.len - 1) & 1) == 1;
}
/* ************************************************************************
* Non-local exits
*************************************************************************/
/** Generate code to invoke the finalizer associated with given
* environment.
* Any calls to finalizers are appended to the environments `cont' chain.
* Mark beginning of gap in catch all range for finalizer.
*/
void genFinalizer(Env<GenContext> env) {
DEBUG.P(this,"genFinalizer(1)");
DEBUG.P("env.info前="+env.info);
if (code.isAlive() && env.info.finalize != null)
env.info.finalize.gen();
DEBUG.P("env.info后="+env.info);
DEBUG.P(0,this,"genFinalizer(1)");
}
/** Generate code to call all finalizers of structures aborted by
* a non-local
* exit. Return target environment of the non-local exit.
* @param target The tree representing the structure that's aborted
* @param env The environment current at the non-local exit.
*/
Env<GenContext> unwind(JCTree target, Env<GenContext> env) {
DEBUG.P(this,"unwind(2)");
DEBUG.P("target="+target);
DEBUG.P("env="+env);
Env<GenContext> env1 = env;
while (true) {
genFinalizer(env1);
if (env1.tree == target) break;
env1 = env1.next;
}
DEBUG.P("env1="+env1);
DEBUG.P(0,this,"unwind(2)");
return env1;
}
/** Mark end of gap in catch-all range for finalizer.
* @param env the environment which might contain the finalizer
* (if it does, env.info.gaps != null).
*/
void endFinalizerGap(Env<GenContext> env) {
DEBUG.P(this,"endFinalizerGap(1)");
DEBUG.P("env.info前="+env.info);
if (env.info.gaps != null && env.info.gaps.length() % 2 == 1)
env.info.gaps.append(code.curPc());
DEBUG.P("env.info后="+env.info);
DEBUG.P(0,this,"endFinalizerGap(1)");
}
/** Mark end of all gaps in catch-all ranges for finalizers of environments
* lying between, and including to two environments.
* @param from the most deeply nested environment to mark
* @param to the least deeply nested environment to mark
*/
void endFinalizerGaps(Env<GenContext> from, Env<GenContext> to) {
DEBUG.P(this,"endFinalizerGaps(2)");
Env<GenContext> last = null;
while (last != to) {
endFinalizerGap(from);
last = from;
from = from.next;
}
DEBUG.P(0,this,"endFinalizerGaps(2)");
}
/** Do any of the structures aborted by a non-local exit have
* finalizers that require an empty stack?
* @param target The tree representing the structure that's aborted
* @param env The environment current at the non-local exit.
*/
boolean hasFinally(JCTree target, Env<GenContext> env) {
boolean hasFinally=true;//我加上的
try {//我加上的
DEBUG.P(this,"hasFinally(2)");
while (env.tree != target) {
if (env.tree.tag == JCTree.TRY && env.info.finalize.hasFinalizer())
return true;
env = env.next;
}
hasFinally=false;//我加上的
return false;
}finally{//我加上的
DEBUG.P("hasFinally="+hasFinally);
DEBUG.P(0,this,"hasFinally(2)");
}
}
/* ************************************************************************
* Normalizing class-members.
*************************************************************************/
/** Distribute member initializer code into constructors and <clinit>
* method.
* @param defs The list of class member declarations.
* @param c The enclosing class.
*/
List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
DEBUG.P(this,"normalizeDefs(2)");
DEBUG.P("c="+c);
ListBuffer<JCStatement> initCode = new ListBuffer<JCStatement>();
ListBuffer<JCStatement> clinitCode = new ListBuffer<JCStatement>();
ListBuffer<JCTree> methodDefs = new ListBuffer<JCTree>();
// Sort definitions into three listbuffers:
// - initCode for instance initializers
// - clinitCode for class initializers
// - methodDefs for method definitions
for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
JCTree def = l.head;
DEBUG.P("");
DEBUG.P("def.tag="+def.myTreeTag());
switch (def.tag) {
case JCTree.BLOCK:
JCBlock block = (JCBlock)def;
DEBUG.P("block.flags="+Flags.toString(block.flags));
if ((block.flags & STATIC) != 0)
clinitCode.append(block);
else
initCode.append(block);
break;
case JCTree.METHODDEF:
methodDefs.append(def);
break;
case JCTree.VARDEF:
JCVariableDecl vdef = (JCVariableDecl) def;
VarSymbol sym = vdef.sym;
DEBUG.P("sym="+sym);
DEBUG.P("vdef.init="+vdef.init);
checkDimension(vdef.pos(), sym.type);//检查变量的类型是否是多维数组，如果是，则维数不能大于255
if (vdef.init != null) {
DEBUG.P("");
DEBUG.P("sym.getConstValue()="+sym.getConstValue());
DEBUG.P("sym.flags()="+Flags.toString(sym.flags()));
if ((sym.flags() & STATIC) == 0) {
// Always initialize instance variables.
JCStatement init = make.at(vdef.pos()).
Assignment(sym, vdef.init);
initCode.append(init);
if (endPositions != null) {
Integer endPos = endPositions.remove(vdef);
if (endPos != null) endPositions.put(init, endPos);
}
} else if (sym.getConstValue() == null) {
// Initialize class (static) variables only if
// they are not compile-time constants.
JCStatement init = make.at(vdef.pos).
Assignment(sym, vdef.init);
DEBUG.P("");
DEBUG.P("init="+init);
clinitCode.append(init);
if (endPositions != null) {
Integer endPos = endPositions.remove(vdef);
if (endPos != null) endPositions.put(init, endPos);
}
} else {//只有已初始化的static final类型变量才是compile-time constants
checkStringConstant(vdef.init.pos(), sym.getConstValue());
}
}
break;
default:
assert false;
}
}
DEBUG.P(2);
DEBUG.P("initCode="+initCode.toList());
DEBUG.P("clinitCode="+clinitCode.toList());
// Insert any instance initializers into all constructors.
if (initCode.length() != 0) {
List<JCStatement> inits = initCode.toList();
for (JCTree t : methodDefs) {
normalizeMethod((JCMethodDecl)t, inits);
}
}
// If there are class initializers, create a <clinit> method
// that contains them as its body.
if (clinitCode.length() != 0) {
MethodSymbol clinit = new MethodSymbol(
STATIC, names.clinit,
new MethodType(
List.<Type>nil(), syms.voidType,
List.<Type>nil(), syms.methodClass),
c);
c.members().enter(clinit);
List<JCStatement> clinitStats = clinitCode.toList();
JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
block.endpos = TreeInfo.endPos(clinitStats.last());
methodDefs.append(make.MethodDef(clinit, block));
DEBUG.P("c.members()="+c.members());
}
DEBUG.P(0,this,"normalizeDefs(2)");
// Return all method definitions.
return methodDefs.toList();
}
/** Check a constant value and report if it is a string that is
* too large.
*/
private void checkStringConstant(DiagnosticPosition pos, Object constValue) {
try {//我加上的
DEBUG.P(this,"checkStringConstant(2)");
DEBUG.P("nerrs="+nerrs+" constValue="+constValue);
if (nerrs != 0 || // only complain about a long string once
constValue == null ||
!(constValue instanceof String) ||
((String)constValue).length() < Pool.MAX_STRING_LENGTH)
return;
log.error(pos, "limit.string");
nerrs++;
}finally{//我加上的
DEBUG.P(0,this,"checkStringConstant(2)");
}
}
/** Insert instance initializer code into initial constructor.
* @param md The tree potentially representing a
* constructor's definition.
* @param initCode The list of instance initializer statements.
*/
void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode) {
/*
//注意:只将initCod插入第一条语句不是this()调用的构造方法中
对于如下源代码:
------------------------------------
public class Test {
int fieldA=10;
{
fieldA=20;
}
{
fieldB=20;
}
int fieldB=10;
}
------------------------------------
经过编译器调整后，看起来像这样:
------------------------------------
public class Test {
Test() {
fieldA=10;
fieldA=20;
fieldB=20;
fieldB=10;
}
}
------------------------------------
最终fieldA的值是20,fieldB的值是10，说明了一点，语句块与变量初始化语句
在源代码中的顺序决定了变量的最终取值
*/
DEBUG.P(this,"normalizeMethod(2)");
DEBUG.P("md.name="+md.name);
DEBUG.P("isInitialConstructor="+TreeInfo.isInitialConstructor(md));
if (md.name == names.init && TreeInfo.isInitialConstructor(md)) {
DEBUG.P("JCMethodDecl md旧="+md);
// We are seeing a constructor that does not call another
// constructor of the same class.
List<JCStatement> stats = md.body.stats;
ListBuffer<JCStatement> newstats = new ListBuffer<JCStatement>();
if (stats.nonEmpty()) {
// Copy initializers of synthetic variables generated in
// the translation of inner classes.
while (TreeInfo.isSyntheticInit(stats.head)) {
DEBUG.P("while1->stats.head="+stats.head);
newstats.append(stats.head);
stats = stats.tail;
}
// Copy superclass constructor call
newstats.append(stats.head);
DEBUG.P("stats.head="+stats.head);
stats = stats.tail;
// Copy remaining synthetic initializers.
while (stats.nonEmpty() &&
TreeInfo.isSyntheticInit(stats.head)) {
DEBUG.P("while2->stats.head="+stats.head);
newstats.append(stats.head);
stats = stats.tail;
}
// Now insert the initializer code.
newstats.appendList(initCode);
// And copy all remaining statements.
while (stats.nonEmpty()) {
newstats.append(stats.head);
stats = stats.tail;
}
}
md.body.stats = newstats.toList();
DEBUG.P("JCMethodDecl md新="+md);
if (md.body.endpos == Position.NOPOS)
md.body.endpos = TreeInfo.endPos(md.body.stats.last());
}
DEBUG.P(0,this,"normalizeMethod(2)");
}
/* ********************************************************************
* Adding miranda methods
*********************************************************************/
/** Add abstract methods for all methods defined in one of
* the interfaces of a given class,
* provided they are not already implemented in the class.
*
* @param c The class whose interfaces are searched for methods
* for which Miranda methods should be added.
*/
void implementInterfaceMethods(ClassSymbol c) {
DEBUG.P(this,"implementInterfaceMethods(1)");
implementInterfaceMethods(c, c);
DEBUG.P(0,this,"implementInterfaceMethods(1)");
}
/** Add abstract methods for all methods defined in one of
* the interfaces of a given class,
* provided they are not already implemented in the class.
*
* @param c The class whose interfaces are searched for methods
* for which Miranda methods should be added.
* @param site The class in which a definition may be needed.
*/
void implementInterfaceMethods(ClassSymbol c, ClassSymbol site) {
DEBUG.P(this,"implementInterfaceMethods(2)");
DEBUG.P("c="+c);
DEBUG.P("site="+site);
for (List<Type> l = types.interfaces(c.type); l.nonEmpty(); l = l.tail) {
ClassSymbol i = (ClassSymbol)l.head.tsym;
for (Scope.Entry e = i.members().elems;
e != null;
e = e.sibling)
{
DEBUG.P("e.sym="+e.sym);
if (e.sym.kind == MTH && (e.sym.flags() & STATIC) == 0)
{
MethodSymbol absMeth = (MethodSymbol)e.sym;
MethodSymbol implMeth = absMeth.binaryImplementation(site, types);
DEBUG.P("implMeth="+implMeth);
if (implMeth == null)
addAbstractMethod(site, absMeth);
//????????如何得到IPROXY?????????/
else if ((implMeth.flags() & IPROXY) != 0)
adjustAbstractMethod(site, implMeth, absMeth);
}
}
implementInterfaceMethods(i, site);
}
DEBUG.P(0,this,"implementInterfaceMethods(2)");
}
/** Add an abstract methods to a class
* which implicitly implements a method defined in some interface
* implemented by the class. These methods are called "Miranda methods".
* Enter the newly created method into its enclosing class scope.
* Note that it is not entered into the class tree, as the emitter
* doesn't need to see it there to emit an abstract method.
*
* @param c The class to which the Miranda method is added.
* @param m The interface method symbol for which a Miranda method
* is added.
*/
private void addAbstractMethod(ClassSymbol c,
MethodSymbol m) {
DEBUG.P(this,"addAbstractMethod(2)");
DEBUG.P("c="+c);
DEBUG.P("m="+m);
MethodSymbol absMeth = new MethodSymbol(
m.flags() | IPROXY | SYNTHETIC, m.name,
m.type, // was c.type.memberType(m), but now only !generics supported
c);
DEBUG.P("absMeth.flags()="+Flags.toString(absMeth.flags()));
c.members().enter(absMeth); // add to symbol table
DEBUG.P("c.members()="+c.members());
DEBUG.P(0,this,"addAbstractMethod(2)");
}
private void adjustAbstractMethod(ClassSymbol c,
MethodSymbol pm,
MethodSymbol im) {
DEBUG.P(this,"adjustAbstractMethod(3)");
DEBUG.P("c="+c);//c是实现类
DEBUG.P("pm="+pm);//实现类c中的方法
DEBUG.P("im="+im);//im是接口中的方法
MethodType pmt = (MethodType)pm.type;
Type imt = types.memberType(c.type, im);
pmt.thrown = chk.intersect(pmt.getThrownTypes(), imt.getThrownTypes());
DEBUG.P(0,this,"adjustAbstractMethod(3)");
}
/* ************************************************************************
* Traversal methods
*************************************************************************/
/** Visitor argument: The current environment.
*/
Env<GenContext> env;
/** Visitor argument: The expected type (prototype).
*/
Type pt;
/** Visitor result: The item representing the computed value.
*/
Item result;
/** Visitor method: generate code for a definition, catching and reporting
* any completion failures.
* @param tree The definition to be visited.
* @param env The environment current at the definition.
*/
public void genDef(JCTree tree, Env<GenContext> env) {
DEBUG.P(this,"genDef(2)");
DEBUG.P("env="+env);
DEBUG.P("tree.tag="+tree.myTreeTag());
DEBUG.P("tree="+tree);
Env<GenContext> prevEnv = this.env;
try {
this.env = env;
tree.accept(this);
} catch (CompletionFailure ex) {
chk.completionError(tree.pos(), ex);
} finally {
this.env = prevEnv;
DEBUG.P(0,this,"genDef(2)");
}
}
/** Derived visitor method: check whether CharacterRangeTable
* should be emitted, if so, put a new entry into CRTable
* and call method to generate bytecode.
* If not, just call method to generate bytecode.
* @see #genStat(Tree, Env)
*
* @param tree The tree to be visited.
* @param env The environment to use.
* @param crtFlags The CharacterRangeTable flags
* indicating type of the entry.
*/
public void genStat(JCTree tree, Env<GenContext> env, int crtFlags) {
try {//我加上的
DEBUG.P(this,"genStat(3)");
DEBUG.P("env="+env);
DEBUG.P("genCrt="+genCrt);
if(code.crt!=null) DEBUG.P("crtFlags="+code.crt.getTypes(crtFlags));
if (!genCrt) {
genStat(tree, env);
return;
}
int startpc = code.curPc();
genStat(tree, env);
if (tree.tag == JCTree.BLOCK) crtFlags |= CRT_BLOCK;
code.crt.put(tree, crtFlags, startpc, code.curPc());
}finally{//我加上的
DEBUG.P(0,this,"genStat(3)");
}
}
/** Derived visitor method: generate code for a statement.
*/
public void genStat(JCTree tree, Env<GenContext> env) {
DEBUG.P(this,"genStat(2)");
DEBUG.P("code.isAlive()="+code.isAlive());
DEBUG.P("env.info.isSwitch="+env.info.isSwitch);
if (code.isAlive()) {
code.statBegin(tree.pos);
genDef(tree, env);
} else if (env.info.isSwitch && tree.tag == JCTree.VARDEF) {
// variables whose declarations are in a switch
// can be used even if the decl is unreachable.
code.newLocal(((JCVariableDecl) tree).sym);
}
DEBUG.P(0,this,"genStat(2)");
}
/** Derived visitor method: check whether CharacterRangeTable
* should be emitted, if so, put a new entry into CRTable
* and call method to generate bytecode.
* If not, just call method to generate bytecode.
* @see #genStats(List, Env)
*
* @param trees The list of trees to be visited.
* @param env The environment to use.
* @param crtFlags The CharacterRangeTable flags
* indicating type of the entry.
*/
public void genStats(List<JCStatement> trees, Env<GenContext> env, int crtFlags) {
try {//我加上的
DEBUG.P(this,"genStats(3)");
DEBUG.P("env="+env);
if(trees!=null) DEBUG.P("trees.size="+trees.size());
else DEBUG.P("trees=null");
DEBUG.P("genCrt="+genCrt);
if(code.crt!=null) DEBUG.P("crtFlags="+code.crt.getTypes(crtFlags));
if (!genCrt) {
genStats(trees, env);
return;
}
if (trees.length() == 1) { // mark one statement with the flags
genStat(trees.head, env, crtFlags | CRT_STATEMENT);
} else {
int startpc = code.curPc();
genStats(trees, env);
code.crt.put(trees, crtFlags, startpc, code.curPc());
}
}finally{//我加上的
DEBUG.P(0,this,"genStats(3)");
}
}
/** Derived visitor method: generate code for a list of statements.
*/
public void genStats(List<? extends JCTree> trees, Env<GenContext> env) {
DEBUG.P(this,"genStats(2)");
DEBUG.P("env="+env);
if(trees!=null) DEBUG.P("trees.size="+trees.size());
else DEBUG.P("trees=null");
for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
genStat(l.head, env, CRT_STATEMENT);
DEBUG.P(0,this,"genStats(2)");
}
/** Derived visitor method: check whether CharacterRangeTable
* should be emitted, if so, put a new entry into CRTable
* and call method to generate bytecode.
* If not, just call method to generate bytecode.
* @see #genCond(Tree,boolean)
*
* @param tree The tree to be visited.
* @param crtFlags The CharacterRangeTable flags
* indicating type of the entry.
*/
public CondItem genCond(JCTree tree, int crtFlags) {
try {//我加上的
DEBUG.P(this,"genCond(2)");
DEBUG.P("genCrt="+genCrt);
if(code.crt!=null) DEBUG.P("crtFlags="+code.crt.getTypes(crtFlags));
if (!genCrt) return genCond(tree, false);
int startpc = code.curPc();
CondItem item = genCond(tree, (crtFlags & CRT_FLOW_CONTROLLER) != 0);
code.crt.put(tree, crtFlags, startpc, code.curPc());
return item;
}finally{//我加上的
DEBUG.P(0,this,"genCond(2)");
}
}
/** Derived visitor method: generate code for a boolean
* expression in a control-flow context.
* @param _tree The expression to be visited.
* @param markBranches The flag to indicate that the condition is
* a flow controller so produced conditions
* should contain a proper tree to generate
* CharacterRangeTable branches for them.
*/
public CondItem genCond(JCTree _tree, boolean markBranches) {
try {//我加上的
DEBUG.P(this,"genCond(JCTree _tree, boolean markBranches)");
DEBUG.P("markBranches="+markBranches);
DEBUG.P("_tree="+_tree);
JCTree inner_tree = TreeInfo.skipParens(_tree);
DEBUG.P("inner_tree="+_tree);
DEBUG.P("inner_tree.tag="+inner_tree.myTreeTag());
if (inner_tree.tag == JCTree.CONDEXPR) {
JCConditional tree = (JCConditional)inner_tree;
CondItem cond = genCond(tree.cond, CRT_FLOW_CONTROLLER);
DEBUG.P("cond="+cond);
DEBUG.P("cond.isTrue() ="+cond.isTrue());
DEBUG.P("cond.isFalse()="+cond.isFalse());
if (cond.isTrue()) {
code.resolve(cond.trueJumps);
CondItem result = genCond(tree.truepart, CRT_FLOW_TARGET);
if (markBranches) result.tree = tree.truepart;
return result;
}
if (cond.isFalse()) {
code.resolve(cond.falseJumps);
CondItem result = genCond(tree.falsepart, CRT_FLOW_TARGET);
if (markBranches) result.tree = tree.falsepart;
return result;
}
Chain secondJumps = cond.jumpFalse();
DEBUG.P("secondJumps="+secondJumps);
code.resolve(cond.trueJumps);
CondItem first = genCond(tree.truepart, CRT_FLOW_TARGET);
if (markBranches) first.tree = tree.truepart;
DEBUG.P("first="+first);
Chain falseJumps = first.jumpFalse();
DEBUG.P("falseJumps="+falseJumps);
code.resolve(first.trueJumps);
Chain trueJumps = code.branch(goto_);
DEBUG.P("trueJumps="+trueJumps);
code.resolve(secondJumps);
CondItem second = genCond(tree.falsepart, CRT_FLOW_TARGET);
DEBUG.P("second="+second);
CondItem result = items.makeCondItem(second.opcode,
code.mergeChains(trueJumps, second.trueJumps),
code.mergeChains(falseJumps, second.falseJumps));
if (markBranches) result.tree = tree.falsepart;
return result;
} else {
CondItem result = genExpr(_tree, syms.booleanType).mkCond();
if (markBranches) result.tree = _tree;
DEBUG.P("result="+result);
return result;
}
}finally{//我加上的
DEBUG.P(0,this,"genCond(JCTree _tree, boolean markBranches)");
}
}
/** Visitor method: generate code for an expression, catching and reporting
* any completion failures.
* @param tree The expression to be visited.
* @param pt The expression's expected type (proto-type).
*/
public Item genExpr(JCTree tree, Type pt) {
DEBUG.P(this,"genExpr(JCTree tree, Type pt)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.type.constValue()="+tree.type.constValue());
DEBUG.P("pt="+pt);
Type prevPt = this.pt;
Item myItemResult=null;//我加上的
try {
if (tree.type.constValue() != null) {
// Short circuit any expressions which are constants
checkStringConstant(tree.pos(), tree.type.constValue());
result = items.makeImmediateItem(tree.type, tree.type.constValue());
} else {
DEBUG.P("tree.tag="+tree.myTreeTag());
this.pt = pt;
tree.accept(this);
}
myItemResult=result.coerce(pt);//我加上的
return myItemResult;//我加上的
//coerce(Type targettype),coerce(int targetcode)在Items.Item中定义,
//只有Items.ImmediateItem覆盖了coerce(int targetcode)
//return result.coerce(pt);
} catch (CompletionFailure ex) {
chk.completionError(tree.pos(), ex);
code.state.stacksize = 1;
return items.makeStackItem(pt);
} finally {
this.pt = prevPt;
DEBUG.P("result="+result);
DEBUG.P("myItemResult="+myItemResult);
DEBUG.P("code.state="+code.state);
DEBUG.P(0,this,"genExpr(JCTree tree, Type pt)");
}
}
/** Derived visitor method: generate code for a list of method arguments.
* @param trees The argument expressions to be visited.
* @param pts The expression's expected types (i.e. the formal parameter
* types of the invoked method).
*/
public void genArgs(List<JCExpression> trees, List<Type> pts) {
DEBUG.P(this,"genArgs(2)");
DEBUG.P("trees="+trees);
DEBUG.P("pts="+pts);
for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail) {
genExpr(l.head, pts.head).load();
pts = pts.tail;
}
// require lists be of same length
assert pts.isEmpty();
DEBUG.P(0,this,"genArgs(2)");
}
/* ************************************************************************
* Visitor methods for statements and definitions
*************************************************************************/
/** Thrown when the byte code size exceeds limit.
*/
public static class CodeSizeOverflow extends RuntimeException {
private static final long serialVersionUID = 0;
public CodeSizeOverflow() {}
}
public void visitMethodDef(JCMethodDecl tree) {
DEBUG.P(this,"visitMethodDef(1)");
// Create a new local environment that points pack at method
// definition.
Env<GenContext> localEnv = env.dup(tree);
localEnv.enclMethod = tree;
DEBUG.P("localEnv="+localEnv);
// The expected type of every return statement in this method
// is the method's return type.
this.pt = tree.sym.erasure(types).getReturnType();
DEBUG.P("tree.sym="+tree.sym);
DEBUG.P("tree.sym.type="+tree.sym.type);
DEBUG.P("this.pt="+this.pt);
DEBUG.P("tree.sym.erasure(types)="+tree.sym.erasure(types));
checkDimension(tree.pos(), tree.sym.erasure(types));
genMethod(tree, localEnv, false);
DEBUG.P(0,this,"visitMethodDef(1)");
}
//where
/** Generate code for a method.
* @param tree The tree representing the method definition.
* @param env The environment current for the method body.
* @param fatcode A flag that indicates whether all jumps are
* within 32K. We first invoke this method under
* the assumption that fatcode == false, i.e. all
* jumps are within 32K. If this fails, fatcode
* is set to true and we try again.
*/
//b10
void genMethod(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
try {//我加上的
DEBUG.P(this,"genMethod(3)");
DEBUG.P("env="+env);
DEBUG.P("fatcode="+fatcode);
//DEBUG.P("tree.body="+tree.body);
MethodSymbol meth = tree.sym;
// System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
/*
由方法每个参数的type计算出所有参数所占的总字数(一个字是堆栈出入栈操作的基本单位)，
(double和long类型的参数占两个字)
如果是非静态方法(隐含this变量,在initCode方法中把this加到局部变量数组中)，
那么总字数再加1，总字数必须小于ClassFile.MAX_PARAMETERS(255)
*/
if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) +
(((tree.mods.flags & STATIC) == 0 || meth.isConstructor()) ? 1 : 0) >
ClassFile.MAX_PARAMETERS) {
log.error(tree.pos(), "limit.parameters");
nerrs++;
}
else if (tree.body != null) { //只有abstract方法时tree.body == null
// Create a new code structure and initialize it.
int startpcCrt = initCode(tree, env, fatcode);
try {
genStat(tree.body, env);
} catch (CodeSizeOverflow e) {
// Failed due to code limit, try again with jsr/ret
startpcCrt = initCode(tree, env, fatcode);
genStat(tree.body, env);
}
DEBUG.P("");
DEBUG.P("code.state.stacksize="+code.state.stacksize);
if (code.state.stacksize != 0) {
log.error(tree.body.pos(), "stack.sim.error", tree);
throw new AssertionError();
}
DEBUG.P("");
DEBUG.P("code.isAlive()="+code.isAlive());
// If last statement could complete normally, insert a
// return at the end.
if (code.isAlive()) {
code.statBegin(TreeInfo.endPos(tree.body));
if (env.enclMethod == null ||
env.enclMethod.sym.type.getReturnType().tag == VOID) {
code.emitop0(return_);
} else {
// sometime dead code seems alive (4415991);
// generate a small loop instead
int startpc = code.entryPoint();
CondItem c = items.makeCondItem(goto_);
code.resolve(c.jumpTrue(), startpc);
}
}
if (genCrt)
code.crt.put(tree.body,
CRT_BLOCK,
startpcCrt,
code.curPc());
// End the scope of all local variables in variable info.
code.endScopes(0);
// If we exceeded limits, panic
if (code.checkLimits(tree.pos(), log)) {
nerrs++;
return;
}
DEBUG.P("");
DEBUG.P("fatcode="+fatcode);
DEBUG.P("code.fatcode="+code.fatcode);
// If we generated short code but got a long jump, do it again
// with fatCode = true.
if (!fatcode && code.fatcode) genMethod(tree, env, true);
// Clean up
if(stackMap == StackMapFormat.JSR202) {
code.lastFrame = null;
code.frameBeforeLast = null;
}
}
}finally{//我加上的
DEBUG.P(0,this,"genMethod(3)");
}
}
private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
try {//我加上的
DEBUG.P(this,"initCode(3)");
DEBUG.P("tree.sym="+tree.sym);
DEBUG.P("env="+env);
DEBUG.P("fatcode="+fatcode);
DEBUG.P("lineDebugInfo="+lineDebugInfo);
DEBUG.P("varDebugInfo="+varDebugInfo);
DEBUG.P("stackMap="+stackMap);
DEBUG.P("debugCode="+debugCode);
DEBUG.P("genCrt="+genCrt);
MethodSymbol meth = tree.sym;
// Create a new code structure.
meth.code = code = new Code(meth,
fatcode,
lineDebugInfo ? toplevel.lineMap : null,
varDebugInfo,
stackMap,
debugCode,
genCrt ? new CRTable(tree, env.toplevel.endPositions)
: null,
syms,
types,
pool);//常量池是所有方法共用的
items = new Items(pool, code, syms, types);//每个方法都重新生成一个Items实例
if (code.debugCode)
System.err.println(meth + " for body " + tree);
// If method is not static, create a new local variable address
// for `this'.
DEBUG.P("tree.mods.flags="+Flags.toString(tree.mods.flags));
if ((tree.mods.flags & STATIC) == 0) {
Type selfType = meth.owner.type;
DEBUG.P("selfType="+selfType);
DEBUG.P("meth.isConstructor()="+meth.isConstructor());
if (meth.isConstructor() && selfType != syms.objectType)
selfType = UninitializedType.uninitializedThis(selfType);
DEBUG.P("selfType="+selfType);
//this变量在局部变量数组的索引总是0
code.setDefined(
code.newLocal(
new VarSymbol(FINAL, names._this, selfType, meth.owner)));
}
// Mark all parameters as defined from the beginning of
// the method.
DEBUG.P("tree.params="+tree.params);
for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
checkDimension(l.head.pos(), l.head.sym.type);
code.setDefined(code.newLocal(l.head.sym));
}
// Get ready to generate code for method body.
int startpcCrt = genCrt ? code.curPc() : 0;
code.entryPoint();
// Suppress initial stackmap
code.pendingStackMap = false;
DEBUG.P("startpcCrt="+startpcCrt);
return startpcCrt;
}finally{//我加上的
DEBUG.P(1,this,"initCode(3)");
}
}
public void visitVarDef(JCVariableDecl tree) {
DEBUG.P(this,"visitVarDef(1)");
VarSymbol v = tree.sym;
code.newLocal(v);
/*
final int myMethodInt; //tree.init==null
final int myMethodInt2=100; //tree.init!=null 且getConstValue()==100
int myMethodInt3=200; //tree.init!=null 但getConstValue()==null
在方法中定义的final类型的且在定义时就被赋值的是编译时常量
*/
DEBUG.P("tree.init="+tree.init);
if (tree.init != null) {
checkStringConstant(tree.init.pos(), v.getConstValue());
DEBUG.P("v.getConstValue()="+v.getConstValue());
DEBUG.P("varDebugInfo="+varDebugInfo);
if (v.getConstValue() == null || varDebugInfo) {
genExpr(tree.init, v.erasure(types)).load();
items.makeLocalItem(v).store();
}
}
checkDimension(tree.pos(), v.type);
DEBUG.P(0,this,"visitVarDef(1)");
}
public void visitSkip(JCSkip tree) {
}
public void visitBlock(JCBlock tree) {
DEBUG.P(this,"visitBlock(JCBlock tree)");
int limit = code.nextreg;
DEBUG.P("limit="+limit);
Env<GenContext> localEnv = env.dup(tree, new GenContext());
genStats(tree.stats, localEnv);
// End the scope of all block-local variables in variable info.
DEBUG.P("");
DEBUG.P("env.tree.tag="+env.tree.myTreeTag());
if (env.tree.tag != JCTree.METHODDEF) {
code.statBegin(tree.endpos);
code.endScopes(limit);
code.pendingStatPos = Position.NOPOS;
}
DEBUG.P(0,this,"visitBlock(JCBlock tree)");
}
public void visitDoLoop(JCDoWhileLoop tree) {
DEBUG.P(this,"visitDoLoop(1)");
genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), false);
DEBUG.P(0,this,"visitDoLoop(1)");
}
public void visitWhileLoop(JCWhileLoop tree) {
DEBUG.P(this,"visitWhileLoop(1)");
genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), true);
DEBUG.P(0,this,"visitWhileLoop(1)");
}
public void visitForLoop(JCForLoop tree) {
DEBUG.P(this,"visitForLoop(1)");
int limit = code.nextreg;
genStats(tree.init, env);
genLoop(tree, tree.body, tree.cond, tree.step, true);
code.endScopes(limit);
DEBUG.P(0,this,"visitForLoop(1)");
}
//where
/** Generate code for a loop.
* @param loop The tree representing the loop.
* @param body The loop's body.
* @param cond The loop's controling condition.
* @param step "Step" statements to be inserted at end of
* each iteration.
* @param testFirst True if the loop test belongs before the body.
*/
private void genLoop(JCStatement loop,
JCStatement body,
JCExpression cond,
List<JCExpressionStatement> step,
boolean testFirst) {
DEBUG.P(this,"genLoop(1)");
DEBUG.P("cond="+cond);
DEBUG.P("testFirst="+testFirst);
Env<GenContext> loopEnv = env.dup(loop, new GenContext());
int startpc = code.entryPoint();
if (testFirst) {
CondItem c;
if (cond != null) {
code.statBegin(cond.pos);
c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
} else {
c = items.makeCondItem(goto_);
}
Chain loopDone = c.jumpFalse();
code.resolve(c.trueJumps);
genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
code.resolve(loopEnv.info.cont);
genStats(step, loopEnv);
code.resolve(code.branch(goto_), startpc);
code.resolve(loopDone);
} else {
genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
code.resolve(loopEnv.info.cont);
genStats(step, loopEnv);
CondItem c;
if (cond != null) {
code.statBegin(cond.pos);
c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
} else {
c = items.makeCondItem(goto_);
}
//do-while语句生成的字节码比while语句生成的字节码高效，因为少了goto指令
code.resolve(c.jumpTrue(), startpc);
code.resolve(c.falseJumps);
}
code.resolve(loopEnv.info.exit);
DEBUG.P(0,this,"genLoop(1)");
}
public void visitForeachLoop(JCEnhancedForLoop tree) {
throw new AssertionError(); // should have been removed by Lower.
}
public void visitLabelled(JCLabeledStatement tree) {
DEBUG.P(this,"visitLabelled(1)");
Env<GenContext> localEnv = env.dup(tree, new GenContext());
genStat(tree.body, localEnv, CRT_STATEMENT);
code.resolve(localEnv.info.exit);
DEBUG.P(0,this,"visitLabelled(1)");
}
public void visitSwitch(JCSwitch tree) {
DEBUG.P(this,"visitSwitch(1)");
int limit = code.nextreg;
assert tree.selector.type.tag != CLASS;
int startpcCrt = genCrt ? code.curPc() : 0;
Item sel = genExpr(tree.selector, syms.intType);
List<JCCase> cases = tree.cases;
if (cases.isEmpty()) {
// We are seeing: switch <sel> {}
sel.load().drop();
if (genCrt)
code.crt.put(TreeInfo.skipParens(tree.selector),
CRT_FLOW_CONTROLLER, startpcCrt, code.curPc());
} else {
// We are seeing a nonempty switch.
sel.load();
if (genCrt)
code.crt.put(TreeInfo.skipParens(tree.selector),
CRT_FLOW_CONTROLLER, startpcCrt, code.curPc());
Env<GenContext> switchEnv = env.dup(tree, new GenContext());
switchEnv.info.isSwitch = true;
// Compute number of labels and minimum and maximum label values.
// For each case, store its label in an array.
int lo = Integer.MAX_VALUE; // minimum label.
int hi = Integer.MIN_VALUE; // maximum label.
int nlabels = 0; // number of labels.
int[] labels = new int[cases.length()]; // the label array.
int defaultIndex = -1; // the index of the default clause.
List<JCCase> l = cases;
for (int i = 0; i < labels.length; i++) {
if (l.head.pat != null) {
int val = ((Number)l.head.pat.type.constValue()).intValue();
labels[i] = val;
if (val < lo) lo = val;
if (hi < val) hi = val;
nlabels++;
} else {
assert defaultIndex == -1;
defaultIndex = i;
}
l = l.tail;
}
// Determine whether to issue a tableswitch or a lookupswitch
// instruction.
long table_space_cost = 4 + ((long) hi - lo + 1); // words
long table_time_cost = 3; // comparisons
long lookup_space_cost = 3 + 2 * (long) nlabels;
long lookup_time_cost = nlabels;
int opcode =
nlabels > 0 &&
table_space_cost + 3 * table_time_cost <=
lookup_space_cost + 3 * lookup_time_cost
?
tableswitch : lookupswitch;
int startpc = code.curPc(); // the position of the selector operation
code.emitop0(opcode);
code.align(4);
int tableBase = code.curPc(); // the start of the jump table
int[] offsets = null; // a table of offsets for a lookupswitch
code.emit4(-1); // leave space for default offset
if (opcode == tableswitch) {
code.emit4(lo); // minimum label
code.emit4(hi); // maximum label
for (long i = lo; i <= hi; i++) { // leave space for jump table
code.emit4(-1);
}
} else {
code.emit4(nlabels); // number of labels
for (int i = 0; i < nlabels; i++) {
code.emit4(-1); code.emit4(-1); // leave space for lookup table
}
offsets = new int[labels.length];
}
Code.State stateSwitch = code.state.dup();
code.markDead();
// For each case do:
l = cases;
for (int i = 0; i < labels.length; i++) {
JCCase c = l.head;
l = l.tail;
int pc = code.entryPoint(stateSwitch);
// Insert offset directly into code or else into the
// offsets table.
if (i != defaultIndex) {
if (opcode == tableswitch) {
code.put4(
tableBase + 4 * (labels[i] - lo + 3),
pc - startpc);
} else {
offsets[i] = pc - startpc;
}
} else {
code.put4(tableBase, pc - startpc);
}
// Generate code for the statements in this case.
genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
}
// Resolve all breaks.
code.resolve(switchEnv.info.exit);
// If we have not set the default offset, we do so now.
if (code.get4(tableBase) == -1) {
code.put4(tableBase, code.entryPoint(stateSwitch) - startpc);
}
if (opcode == tableswitch) {
// Let any unfilled slots point to the default case.
int defaultOffset = code.get4(tableBase);
for (long i = lo; i <= hi; i++) {
int t = (int)(tableBase + 4 * (i - lo + 3));
if (code.get4(t) == -1)
code.put4(t, defaultOffset);
}
} else {
// Sort non-default offsets and copy into lookup table.
if (defaultIndex >= 0)
for (int i = defaultIndex; i < labels.length - 1; i++) {
labels[i] = labels[i+1];
offsets[i] = offsets[i+1];
}
if (nlabels > 0)
qsort2(labels, offsets, 0, nlabels - 1);
for (int i = 0; i < nlabels; i++) {
int caseidx = tableBase + 8 * (i + 1);
code.put4(caseidx, labels[i]);
code.put4(caseidx + 4, offsets[i]);
}
}
}
code.endScopes(limit);
DEBUG.P(0,this,"visitSwitch(1)");
}
//where
/** Sort (int) arrays of keys and values
*/
static void qsort2(int[] keys, int[] values, int lo, int hi) {
int i = lo;
int j = hi;
int pivot = keys[(i+j)/2];
do {
while (keys[i] < pivot) i++;
while (pivot < keys[j]) j--;
if (i <= j) {
int temp1 = keys[i];
keys[i] = keys[j];
keys[j] = temp1;
int temp2 = values[i];
values[i] = values[j];
values[j] = temp2;
i++;
j--;
}
} while (i <= j);
if (lo < j) qsort2(keys, values, lo, j);
if (i < hi) qsort2(keys, values, i, hi);
}
public void visitSynchronized(JCSynchronized tree) {
DEBUG.P(this,"visitSynchronized(1)");
int limit = code.nextreg;
// Generate code to evaluate lock and save in temporary variable.
final LocalItem lockVar = makeTemp(syms.objectType);
genExpr(tree.lock, tree.lock.type).load().duplicate();
lockVar.store();
// Generate code to enter monitor.
code.emitop0(monitorenter);
code.state.lock(lockVar.reg);
// Generate code for a try statement with given body, no catch clauses
// in a new environment with the "exit-monitor" operation as finalizer.
final Env<GenContext> syncEnv = env.dup(tree, new GenContext());
syncEnv.info.finalize = new GenFinalizer() {
void gen() {
DEBUG.P(this,"gen()");
genLast();
assert syncEnv.info.gaps.length() % 2 == 0;
syncEnv.info.gaps.append(code.curPc());
DEBUG.P(0,this,"gen()");
}
void genLast() {
DEBUG.P(this,"genLast()");
DEBUG.P("code.isAlive()="+code.isAlive());
if (code.isAlive()) {
lockVar.load();
code.emitop0(monitorexit);
code.state.unlock(lockVar.reg);
}
DEBUG.P(0,this,"genLast()");
}
};
syncEnv.info.gaps = new ListBuffer<Integer>();
genTry(tree.body, List.<JCCatch>nil(), syncEnv);
code.endScopes(limit);
DEBUG.P(0,this,"visitSynchronized(1)");
}
public void visitTry(final JCTry tree) {
DEBUG.P(this,"visitTry(1)");
// Generate code for a try statement with given body and catch clauses,
// in a new environment which calls the finally block if there is one.
final Env<GenContext> tryEnv = env.dup(tree, new GenContext());
final Env<GenContext> oldEnv = env;
DEBUG.P("tryEnv="+tryEnv);
DEBUG.P("oldEnv="+oldEnv);
DEBUG.P("useJsrLocally="+useJsrLocally);
DEBUG.P("stackMap="+stackMap);
DEBUG.P("jsrlimit="+jsrlimit);
if (!useJsrLocally) {
useJsrLocally =
(stackMap == StackMapFormat.NONE) &&
(jsrlimit <= 0 ||
jsrlimit < 100 &&
estimateCodeComplexity(tree.finalizer)>jsrlimit);
}
DEBUG.P("useJsrLocally="+useJsrLocally);
tryEnv.info.finalize = new GenFinalizer() {
void gen() {
DEBUG.P(this,"gen()");
DEBUG.P("useJsrLocally="+useJsrLocally);
if (useJsrLocally) {
if (tree.finalizer != null) {
Code.State jsrState = code.state.dup();
jsrState.push(code.jsrReturnValue);
tryEnv.info.cont =
new Chain(code.emitJump(jsr),
tryEnv.info.cont,
jsrState);
}
assert tryEnv.info.gaps.length() % 2 == 0;
tryEnv.info.gaps.append(code.curPc());
} else {
assert tryEnv.info.gaps.length() % 2 == 0;
tryEnv.info.gaps.append(code.curPc());
genLast();
}
DEBUG.P(0,this,"gen()");
}
void genLast() {
DEBUG.P(this,"genLast()");
if (tree.finalizer != null)
genStat(tree.finalizer, oldEnv, CRT_BLOCK);
DEBUG.P(0,this,"genLast()");
}
boolean hasFinalizer() {
return tree.finalizer != null;
}
};
tryEnv.info.gaps = new ListBuffer<Integer>();
genTry(tree.body, tree.catchers, tryEnv);
DEBUG.P(0,this,"visitTry(1)");
}
//where
/** Generate code for a try or synchronized statement
* @param body The body of the try or synchronized statement.
* @param catchers The lis of catch clauses.
* @param env the environment current for the body.
*/
void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
DEBUG.P(this,"genTry(3)");
int limit = code.nextreg;
int startpc = code.curPc();
Code.State stateTry = code.state.dup();
genStat(body, env, CRT_BLOCK);
int endpc = code.curPc();
boolean hasFinalizer =
env.info.finalize != null &&
env.info.finalize.hasFinalizer();
List<Integer> gaps = env.info.gaps.toList();
code.statBegin(TreeInfo.endPos(body));
genFinalizer(env);
code.statBegin(TreeInfo.endPos(env.tree));
Chain exitChain = code.branch(goto_);
endFinalizerGap(env);
DEBUG.P("startpc="+startpc);
DEBUG.P("endpc ="+endpc);
if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
// start off with exception on stack
code.entryPoint(stateTry, l.head.param.sym.type);
genCatch(l.head, env, startpc, endpc, gaps);
genFinalizer(env);
if (hasFinalizer || l.tail.nonEmpty()) {
code.statBegin(TreeInfo.endPos(env.tree));
exitChain = code.mergeChains(exitChain,
code.branch(goto_));
}
endFinalizerGap(env);
}
DEBUG.P("hasFinalizer="+hasFinalizer);
if (hasFinalizer) {
// Create a new register segement to avoid allocating
// the same variables in finalizers and other statements.
code.newRegSegment();
// Add a catch-all clause.
// start off with exception on stack
int catchallpc = code.entryPoint(stateTry, syms.throwableType);
DEBUG.P("catchallpc="+catchallpc);
// Register all exception ranges for catch all clause.
// The range of the catch all clause is from the beginning
// of the try or synchronized block until the present
// code pointer excluding all gaps in the current
// environment's GenContext.
int startseg = startpc;
DEBUG.P("startseg="+startseg);
DEBUG.P("env.info="+env.info);
while (env.info.gaps.nonEmpty()) {
int endseg = env.info.gaps.next().intValue();
DEBUG.P("");
DEBUG.P("endseg="+endseg);
registerCatch(body.pos(), startseg, endseg,
catchallpc, 0);
startseg = env.info.gaps.next().intValue();
}
code.statBegin(TreeInfo.finalizerPos(env.tree));
code.markStatBegin();
Item excVar = makeTemp(syms.throwableType);
excVar.store();
genFinalizer(env);
excVar.load();
registerCatch(body.pos(), startseg,
env.info.gaps.next().intValue(),
catchallpc, 0);
code.emitop0(athrow);
code.markDead();
// If there are jsr's to this finalizer, ...
DEBUG.P("env.info.cont="+env.info.cont);
if (env.info.cont != null) {
// Resolve all jsr's.
code.resolve(env.info.cont);
// Mark statement line number
code.statBegin(TreeInfo.finalizerPos(env.tree));
code.markStatBegin();
// Save return address.
LocalItem retVar = makeTemp(syms.throwableType);
retVar.store();
// Generate finalizer code.
env.info.finalize.genLast();
// Return.
code.emitop1w(ret, retVar.reg);
code.markDead();
}
}
// Resolve all breaks.
code.resolve(exitChain);
// End the scopes of all try-local variables in variable info.
code.endScopes(limit);
DEBUG.P(0,this,"genTry(3)");
}
/** Generate code for a catch clause.
* @param tree The catch clause.
* @param env The environment current in the enclosing try.
* @param startpc Start pc of try-block.
* @param endpc End pc of try-block.
*/
void genCatch(JCCatch tree,
Env<GenContext> env,
int startpc, int endpc,
List<Integer> gaps) {
DEBUG.P(this,"genCatch(4)");
DEBUG.P("startpc="+startpc);
DEBUG.P("endpc="+endpc);
DEBUG.P("gaps="+gaps);
if (startpc != endpc) {
int catchType = makeRef(tree.pos(), tree.param.type);
while (gaps.nonEmpty()) {
int end = gaps.head.intValue();
registerCatch(tree.pos(),
startpc, end, code.curPc(),
catchType);
gaps = gaps.tail;
startpc = gaps.head.intValue();
gaps = gaps.tail;
}
DEBUG.P("startpc="+startpc);
DEBUG.P("endpc="+endpc);
if (startpc < endpc)
registerCatch(tree.pos(),
startpc, endpc, code.curPc(),
catchType);
VarSymbol exparam = tree.param.sym;
DEBUG.P("exparam="+exparam);
code.statBegin(tree.pos);
code.markStatBegin();
int limit = code.nextreg;
int exlocal = code.newLocal(exparam);
items.makeLocalItem(exparam).store();
code.statBegin(TreeInfo.firstStatPos(tree.body));
genStat(tree.body, env, CRT_BLOCK);
code.endScopes(limit);
code.statBegin(TreeInfo.endPos(tree.body));
}
DEBUG.P(0,this,"genCatch(4)");
}
/** Register a catch clause in the "Exceptions" code-attribute.
*/
void registerCatch(DiagnosticPosition pos,
int startpc, int endpc,
int handler_pc, int catch_type) {
//handler_pc是catch子句中第一条指令的偏移量，
//catch_type是捕获的异常类在常量池中的索引
DEBUG.P(this,"registerCatch(5)");
DEBUG.P("startpc="+startpc);
DEBUG.P("endpc="+endpc);
if (startpc != endpc) {
char startpc1 = (char)startpc;
char endpc1 = (char)endpc;
char handler_pc1 = (char)handler_pc;
if (startpc1 == startpc &&
endpc1 == endpc &&
handler_pc1 == handler_pc) {
code.addCatch(startpc1, endpc1, handler_pc1,
(char)catch_type);
} else {
if (!useJsrLocally && !target.generateStackMapTable()) {
useJsrLocally = true;
throw new CodeSizeOverflow();
} else {
log.error(pos, "limit.code.too.large.for.try.stmt");
nerrs++;
}
}
}
DEBUG.P(0,this,"registerCatch(5)");
}
/** Very roughly estimate the number of instructions needed for
* the given tree.
*/
int estimateCodeComplexity(JCTree tree) {
if (tree == null) return 0;
class ComplexityScanner extends TreeScanner {
int complexity = 0;
public void scan(JCTree tree) {
if (complexity > jsrlimit) return;
super.scan(tree);
}
public void visitClassDef(JCClassDecl tree) {}
public void visitDoLoop(JCDoWhileLoop tree)
{ super.visitDoLoop(tree); complexity++; }
public void visitWhileLoop(JCWhileLoop tree)
{ super.visitWhileLoop(tree); complexity++; }
public void visitForLoop(JCForLoop tree)
{ super.visitForLoop(tree); complexity++; }
public void visitSwitch(JCSwitch tree)
{ super.visitSwitch(tree); complexity+=5; }
public void visitCase(JCCase tree)
{ super.visitCase(tree); complexity++; }
public void visitSynchronized(JCSynchronized tree)
{ super.visitSynchronized(tree); complexity+=6; }
public void visitTry(JCTry tree)
{ super.visitTry(tree);
if (tree.finalizer != null) complexity+=6; }
public void visitCatch(JCCatch tree)
{ super.visitCatch(tree); complexity+=2; }
public void visitConditional(JCConditional tree)
{ super.visitConditional(tree); complexity+=2; }
public void visitIf(JCIf tree)
{ super.visitIf(tree); complexity+=2; }
// note: for break, continue, and return we don't take unwind() into account.
public void visitBreak(JCBreak tree)
{ super.visitBreak(tree); complexity+=1; }
public void visitContinue(JCContinue tree)
{ super.visitContinue(tree); complexity+=1; }
public void visitReturn(JCReturn tree)
{ super.visitReturn(tree); complexity+=1; }
public void visitThrow(JCThrow tree)
{ super.visitThrow(tree); complexity+=1; }
public void visitAssert(JCAssert tree)
{ super.visitAssert(tree); complexity+=5; }
public void visitApply(JCMethodInvocation tree)
{ super.visitApply(tree); complexity+=2; }
public void visitNewClass(JCNewClass tree)
{ scan(tree.encl); scan(tree.args); complexity+=2; }
public void visitNewArray(JCNewArray tree)
{ super.visitNewArray(tree); complexity+=5; }
public void visitAssign(JCAssign tree)
{ super.visitAssign(tree); complexity+=1; }
public void visitAssignop(JCAssignOp tree)
{ super.visitAssignop(tree); complexity+=2; }
public void visitUnary(JCUnary tree)
{ complexity+=1;
if (tree.type.constValue() == null) super.visitUnary(tree); }
public void visitBinary(JCBinary tree)
{ complexity+=1;
if (tree.type.constValue() == null) super.visitBinary(tree); }
public void visitTypeTest(JCInstanceOf tree)
{ super.visitTypeTest(tree); complexity+=1; }
public void visitIndexed(JCArrayAccess tree)
{ super.visitIndexed(tree); complexity+=1; }
public void visitSelect(JCFieldAccess tree)
{ super.visitSelect(tree);
if (tree.sym.kind == VAR) complexity+=1; }
public void visitIdent(JCIdent tree) {
if (tree.sym.kind == VAR) {
complexity+=1;
if (tree.type.constValue() == null &&
tree.sym.owner.kind == TYP)
complexity+=1;
}
}
public void visitLiteral(JCLiteral tree)
{ complexity+=1; }
public void visitTree(JCTree tree) {}
public void visitWildcard(JCWildcard tree) {
throw new AssertionError(this.getClass().getName());
}
}
ComplexityScanner scanner = new ComplexityScanner();
tree.accept(scanner);
return scanner.complexity;
}
public void visitIf(JCIf tree) {
DEBUG.P(this,"visitIf(1)");
int limit = code.nextreg;
Chain thenExit = null;
DEBUG.P("limit="+limit);
//在genCond也调用了TreeInfo.skipParens，这里重复了
DEBUG.P("tree.cond="+tree.cond);
CondItem c = genCond(TreeInfo.skipParens(tree.cond),
CRT_FLOW_CONTROLLER);
DEBUG.P("c="+c);
Chain elseChain = c.jumpFalse();
DEBUG.P("elseChain="+elseChain);
DEBUG.P("c.isFalse()="+c.isFalse());
if (!c.isFalse()) {
code.resolve(c.trueJumps);
genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
thenExit = code.branch(goto_);
}
if (elseChain != null) {
code.resolve(elseChain);
if (tree.elsepart != null)
genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
}
code.resolve(thenExit);
code.endScopes(limit);
DEBUG.P(0,this,"visitIf(1)");
}
public void visitExec(JCExpressionStatement tree) {
DEBUG.P(this,"visitExec(1)");
DEBUG.P("tree.expr.tag="+tree.expr.myTreeTag());
// Optimize x++ to ++x and x-- to --x.
if (tree.expr.tag == JCTree.POSTINC) tree.expr.tag = JCTree.PREINC;
else if (tree.expr.tag == JCTree.POSTDEC) tree.expr.tag = JCTree.PREDEC;
genExpr(tree.expr, tree.expr.type).drop();
DEBUG.P(0,this,"visitExec(1)");
}
public void visitBreak(JCBreak tree) {
DEBUG.P(this,"visitBreak(1)");
DEBUG.P("tree.label="+tree.label);
DEBUG.P("tree.target="+tree.target);
Env<GenContext> targetEnv = unwind(tree.target, env);
assert code.state.stacksize == 0;
targetEnv.info.addExit(code.branch(goto_));
endFinalizerGaps(env, targetEnv);
DEBUG.P(0,this,"visitBreak(1)");
}
public void visitContinue(JCContinue tree) {
DEBUG.P(this,"visitContinue(1)");
DEBUG.P("tree.label="+tree.label);
DEBUG.P("tree.target="+tree.target);
Env<GenContext> targetEnv = unwind(tree.target, env);
assert code.state.stacksize == 0;
targetEnv.info.addCont(code.branch(goto_));
endFinalizerGaps(env, targetEnv);
DEBUG.P(0,this,"visitContinue(1)");
}
public void visitReturn(JCReturn tree) {
DEBUG.P(this,"visitReturn(1)");
DEBUG.P("tree.expr="+tree.expr);
int limit = code.nextreg;
final Env<GenContext> targetEnv;
if (tree.expr != null) {
Item r = genExpr(tree.expr, pt).load();
if (hasFinally(env.enclMethod, env)) {
r = makeTemp(pt);
r.store();
}
targetEnv = unwind(env.enclMethod, env);
r.load();
code.emitop0(ireturn + Code.truncate(Code.typecode(pt)));
} else {
targetEnv = unwind(env.enclMethod, env);
code.emitop0(return_);
}
endFinalizerGaps(env, targetEnv);
code.endScopes(limit);
DEBUG.P(0,this,"visitReturn(1)");
}
public void visitThrow(JCThrow tree) {
DEBUG.P(this,"visitThrow(1)");
genExpr(tree.expr, tree.expr.type).load();
code.emitop0(athrow);
DEBUG.P(0,this,"visitThrow(1)");
}
/* ************************************************************************
* Visitor methods for expressions
*************************************************************************/
public void visitApply(JCMethodInvocation tree) {
DEBUG.P(this,"visitApply(1)");
// Generate code for method.
Item m = genExpr(tree.meth, methodType);
// Generate code for all arguments, where the expected types are
// the parameters of the method's external type (that is, any implicit
// outer instance of a super(...) call appears as first parameter).
genArgs(tree.args,
TreeInfo.symbol(tree.meth).externalType(types).getParameterTypes());
result = m.invoke();
DEBUG.P(0,this,"visitApply(1)");
}
public void visitConditional(JCConditional tree) {
DEBUG.P(this,"visitConditional(1)");
Chain thenExit = null;
CondItem c = genCond(tree.cond, CRT_FLOW_CONTROLLER);
Chain elseChain = c.jumpFalse();
if (!c.isFalse()) {
code.resolve(c.trueJumps);
int startpc = genCrt ? code.curPc() : 0;
genExpr(tree.truepart, pt).load();
code.state.forceStackTop(tree.type);
if (genCrt) code.crt.put(tree.truepart, CRT_FLOW_TARGET,
startpc, code.curPc());
thenExit = code.branch(goto_);
}
if (elseChain != null) {
code.resolve(elseChain);
int startpc = genCrt ? code.curPc() : 0;
genExpr(tree.falsepart, pt).load();
code.state.forceStackTop(tree.type);
if (genCrt) code.crt.put(tree.falsepart, CRT_FLOW_TARGET,
startpc, code.curPc());
}
code.resolve(thenExit);
result = items.makeStackItem(pt);
DEBUG.P(0,this,"visitConditional(1)");
}
public void visitNewClass(JCNewClass tree) {
DEBUG.P(this,"visitNewClass(1)");
// Enclosing instances or anonymous classes should have been eliminated
// by now.
assert tree.encl == null && tree.def == null;
code.emitop2(new_, makeRef(tree.pos(), tree.type));
code.emitop0(dup);
// Generate code for all arguments, where the expected types are
// the parameters of the constructor's external type (that is,
// any implicit outer instance appears as first parameter).
genArgs(tree.args, tree.constructor.externalType(types).getParameterTypes());
items.makeMemberItem(tree.constructor, true).invoke();
result = items.makeStackItem(tree.type);
DEBUG.P(0,this,"visitNewClass(1)");
}
public void visitNewArray(JCNewArray tree) {
DEBUG.P(this,"visitNewArray(1)");
DEBUG.P("tree.elems="+tree.elems);
if (tree.elems != null) {
Type elemtype = types.elemtype(tree.type);
loadIntConst(tree.elems.length());
Item arr = makeNewArray(tree.pos(), tree.type, 1);
DEBUG.P("arr="+arr);
int i = 0;
for (List<JCExpression> l = tree.elems; l.nonEmpty(); l = l.tail) {
arr.duplicate();
loadIntConst(i);
i++;
genExpr(l.head, elemtype).load();
items.makeIndexedItem(elemtype).store();
}
result = arr;
} else {
for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
genExpr(l.head, syms.intType).load();
}
result = makeNewArray(tree.pos(), tree.type, tree.dims.length());
}
DEBUG.P(0,this,"visitNewArray(1)");
}
//where
/** Generate code to create an array with given element type and number
* of dimensions.
*/
Item makeNewArray(DiagnosticPosition pos, Type type, int ndims) {
try {//我加上的
DEBUG.P(this,"makeNewArray(3)");
DEBUG.P("type="+type);
DEBUG.P("ndims="+ndims);
Type elemtype = types.elemtype(type);
if (types.dimensions(elemtype) + ndims > ClassFile.MAX_DIMENSIONS) {
log.error(pos, "limit.dimensions");
nerrs++;
}
int elemcode = Code.arraycode(elemtype);
DEBUG.P("elemcode="+elemcode);
if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
code.emitAnewarray(makeRef(pos, elemtype), type);
} else if (elemcode == 1) {
code.emitMultianewarray(ndims, makeRef(pos, type), type);
} else {
code.emitNewarray(elemcode, type);
}
return items.makeStackItem(type);
}finally{//我加上的
DEBUG.P(0,this,"makeNewArray(3)");
}
}
public void visitParens(JCParens tree) {
DEBUG.P(this,"visitParens(1)");
result = genExpr(tree.expr, tree.expr.type);
DEBUG.P(0,this,"visitParens(1)");
}
public void visitAssign(JCAssign tree) {
DEBUG.P(this,"visitAssign(1)");
Item l = genExpr(tree.lhs, tree.lhs.type);
genExpr(tree.rhs, tree.lhs.type).load();
result = items.makeAssignItem(l);
DEBUG.P(0,this,"visitAssign(1)");
}
public void visitAssignop(JCAssignOp tree) {
DEBUG.P(this,"visitAssignop(1)");
OperatorSymbol operator = (OperatorSymbol) tree.operator;
DEBUG.P("operator.opcode="+code.mnem(operator.opcode));
DEBUG.P("tree="+tree);
DEBUG.P("tree.tag="+tree.myTreeTag());
Item l;
if (operator.opcode == string_add) {
// Generate code to make a string buffer
makeStringBuffer(tree.pos());
// Generate code for first string, possibly save one
// copy under buffer
l = genExpr(tree.lhs, tree.lhs.type);
DEBUG.P("Item l="+l);
DEBUG.P("l.width()="+l.width());
if (l.width() > 0) {
code.emitop0(dup_x1 + 3 * (l.width() - 1));
}
// Load first string and append to buffer.
l.load();
appendString(tree.lhs);
// Append all other strings to buffer.
appendStrings(tree.rhs);
// Convert buffer to string.
bufferToString(tree.pos());
} else {
// Generate code for first expression
l = genExpr(tree.lhs, tree.lhs.type);
// If we have an increment of -32768 to +32767 of a local
// int variable we can use an incr instruction instead of
// proceeding further.
if ((tree.tag == JCTree.PLUS_ASG || tree.tag == JCTree.MINUS_ASG) &&
l instanceof LocalItem &&
tree.lhs.type.tag <= INT &&
tree.rhs.type.tag <= INT &&
tree.rhs.type.constValue() != null) {
int ival = ((Number) tree.rhs.type.constValue()).intValue();
if (tree.tag == JCTree.MINUS_ASG) ival = -ival;
((LocalItem)l).incr(ival);
result = l;
return;
}
// Otherwise, duplicate expression, load one copy
// and complete binary operation.
l.duplicate();
l.coerce(operator.type.getParameterTypes().head).load();
completeBinop(tree.lhs, tree.rhs, operator).coerce(tree.lhs.type);
}
result = items.makeAssignItem(l);
DEBUG.P(0,this,"visitAssignop(1)");
}
public void visitUnary(JCUnary tree) {
DEBUG.P(this,"visitUnary(1)");
OperatorSymbol operator = (OperatorSymbol)tree.operator;
DEBUG.P("tree.tag="+tree.myTreeTag());
if (tree.tag == JCTree.NOT) {
CondItem od = genCond(tree.arg, false);
result = od.negate();
} else {
Item od = genExpr(tree.arg, operator.type.getParameterTypes().head);
DEBUG.P("od="+od);
DEBUG.P("tree.tag="+tree.myTreeTag());
DEBUG.P("operator.opcode="+code.mnem(operator.opcode));
switch (tree.tag) {
case JCTree.POS:
result = od.load();
break;
case JCTree.NEG:
result = od.load();
code.emitop0(operator.opcode);
break;
case JCTree.COMPL:
result = od.load();
emitMinusOne(od.typecode);
code.emitop0(operator.opcode);
break;
case JCTree.PREINC: case JCTree.PREDEC:
od.duplicate();
if (od instanceof LocalItem &&
(operator.opcode == iadd || operator.opcode == isub)) {
((LocalItem)od).incr(tree.tag == JCTree.PREINC ? 1 : -1);
result = od;
} else {
od.load();
code.emitop0(one(od.typecode));
code.emitop0(operator.opcode);
// Perform narrowing primitive conversion if byte,
// char, or short. Fix for 4304655.
if (od.typecode != INTcode &&
Code.truncate(od.typecode) == INTcode)
code.emitop0(int2byte + od.typecode - BYTEcode);
result = items.makeAssignItem(od);
}
break;
case JCTree.POSTINC: case JCTree.POSTDEC:
od.duplicate();
if (od instanceof LocalItem &&
(operator.opcode == iadd || operator.opcode == isub)) {
Item res = od.load();
((LocalItem)od).incr(tree.tag == JCTree.POSTINC ? 1 : -1);
result = res;
} else {
Item res = od.load();
od.stash(od.typecode);
code.emitop0(one(od.typecode));
code.emitop0(operator.opcode);
// Perform narrowing primitive conversion if byte,
// char, or short. Fix for 4304655.
if (od.typecode != INTcode &&
Code.truncate(od.typecode) == INTcode)
code.emitop0(int2byte + od.typecode - BYTEcode);
od.store();
result = res;
}
break;
case JCTree.NULLCHK:
result = od.load();
code.emitop0(dup);
genNullCheck(tree.pos());
break;
default:
assert false;
}
}
DEBUG.P(0,this,"visitUnary(1)");
}
/** Generate a null check from the object value at stack top. */
private void genNullCheck(DiagnosticPosition pos) {
callMethod(pos, syms.objectType, names.getClass,
List.<Type>nil(), false);
code.emitop0(pop);
}
public void visitBinary(JCBinary tree) {
DEBUG.P(this,"visitBinary(1)");
OperatorSymbol operator = (OperatorSymbol)tree.operator;
DEBUG.P("tree.tag="+tree.myTreeTag());
DEBUG.P("operator.opcode="+code.mnem(operator.opcode));
if (operator.opcode == string_add) {
// Create a string buffer.
makeStringBuffer(tree.pos());
// Append all strings to buffer.
appendStrings(tree);
// Convert buffer to string.
bufferToString(tree.pos());
result = items.makeStackItem(syms.stringType);
} else if (tree.tag == JCTree.AND) {
CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
if (!lcond.isFalse()) {
Chain falseJumps = lcond.jumpFalse();
code.resolve(lcond.trueJumps);
CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
result = items.
makeCondItem(rcond.opcode,
rcond.trueJumps,
code.mergeChains(falseJumps,
rcond.falseJumps));
} else {
result = lcond;
}
} else if (tree.tag == JCTree.OR) {
CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
if (!lcond.isTrue()) {
Chain trueJumps = lcond.jumpTrue();
code.resolve(lcond.falseJumps);
CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
result = items.
makeCondItem(rcond.opcode,
code.mergeChains(trueJumps, rcond.trueJumps),
rcond.falseJumps);
} else {
result = lcond;
}
} else {
Item od = genExpr(tree.lhs, operator.type.getParameterTypes().head);
od.load();
result = completeBinop(tree.lhs, tree.rhs, operator);
}
DEBUG.P(0,this,"visitBinary(1)");
}
//where
/** Make a new string buffer.
*/
void makeStringBuffer(DiagnosticPosition pos) {
DEBUG.P(this,"makeStringBuffer(1)");
code.emitop2(new_, makeRef(pos, stringBufferType));
code.emitop0(dup);
callMethod(
pos, stringBufferType, names.init, List.<Type>nil(), false);
DEBUG.P(0,this,"makeStringBuffer(1)");
}
/** Append value (on tos) to string buffer (on tos - 1).
*/
void appendString(JCTree tree) {
DEBUG.P(this,"appendString(1)");
DEBUG.P("tree="+tree);
Type t = tree.type.baseType();
if (t.tag > lastBaseTag && t.tsym != syms.stringType.tsym) {
t = syms.objectType;
}
items.makeMemberItem(getStringBufferAppend(tree, t), false).invoke();
DEBUG.P(0,this,"appendString(1)");
}
Symbol getStringBufferAppend(JCTree tree, Type t) {
DEBUG.P(this,"getStringBufferAppend(2)");
DEBUG.P("tree="+tree);
DEBUG.P("t="+t);
assert t.constValue() == null;
Symbol method = stringBufferAppend.get(t);
DEBUG.P("method="+method);
if (method == null) {
method = rs.resolveInternalMethod(tree.pos(),
attrEnv,
stringBufferType,
names.append,
List.of(t),
null);
stringBufferAppend.put(t, method);
}
DEBUG.P("method="+method);
DEBUG.P(0,this,"getStringBufferAppend(2)");
return method;
}
/** Add all strings in tree to string buffer.
*/
void appendStrings(JCTree tree) {
try {//我加上的
DEBUG.P(this,"appendStrings(1)");
tree = TreeInfo.skipParens(tree);
DEBUG.P("tree="+tree);
DEBUG.P("tree.tag="+tree.myTreeTag());
if (tree.tag == JCTree.PLUS && tree.type.constValue() == null) {
JCBinary op = (JCBinary) tree;
if (op.operator.kind == MTH &&
((OperatorSymbol) op.operator).opcode == string_add) {
appendStrings(op.lhs);
appendStrings(op.rhs);
return;
}
}
genExpr(tree, tree.type).load();
appendString(tree);
}finally{//我加上的
DEBUG.P(0,this,"appendStrings(2)");
}
}
/** Convert string buffer on tos to string.
*/
void bufferToString(DiagnosticPosition pos) {
DEBUG.P(this,"bufferToString(1)");
callMethod(
pos,
stringBufferType,
names.toString,
List.<Type>nil(),
false);
DEBUG.P(0,this,"bufferToString(1)");
}
/** Complete generating code for operation, with left operand
* already on stack.
* @param lhs The tree representing the left operand.
* @param rhs The tree representing the right operand.
* @param operator The operator symbol.
*/
Item completeBinop(JCTree lhs, JCTree rhs, OperatorSymbol operator) {
try {//我加上的
DEBUG.P(this,"completeBinop(3)");
DEBUG.P("lhs="+lhs);
DEBUG.P("rhs="+rhs);
DEBUG.P("operator="+operator);
DEBUG.P("operator.opcode="+code.mnem(operator.opcode));
MethodType optype = (MethodType)operator.type;
int opcode = operator.opcode;
if (opcode >= if_icmpeq && opcode <= if_icmple &&
rhs.type.constValue() instanceof Number &&
((Number) rhs.type.constValue()).intValue() == 0) {
//如果关系运算符右边的操作数是0，把if_icmpeq到if_icmple这6条指令
//转换成ifeq到ifle这6条指令，这样就不用将右边的操作数0压入堆栈了
opcode = opcode + (ifeq - if_icmpeq);
} else if (opcode >= if_acmpeq && opcode <= if_acmpne &&
TreeInfo.isNull(rhs)) {
//如果关系运算符右边的操作数是null，把if_acmpeq转换成if_acmp_null，
//把if_acmpne转换成if_acmp_nonnull。
opcode = opcode + (if_acmp_null - if_acmpeq);
} else {
// The expected type of the right operand is
// the second parameter type of the operator, except for
// shifts with long shiftcount, where we convert the opcode
// to a short shift and the expected type to int.
Type rtype = operator.erasure(types).getParameterTypes().tail.head;
DEBUG.P("");
DEBUG.P("operator.type="+operator.type);
DEBUG.P("operator.erasure(types).getParameterTypes()="+operator.erasure(types).getParameterTypes());
DEBUG.P("rtype="+rtype);
if (opcode >= ishll && opcode <= lushrl) {
//把ishll到lushrl这6条非标准指令转换成ishl到lushr这6条指令，
opcode = opcode + (ishl - ishll);
rtype = syms.intType;
}
DEBUG.P("opcode="+code.mnem(opcode));
// Generate code for right operand and load.
genExpr(rhs, rtype).load();
// If there are two consecutive opcode instructions,
// emit the first now.
if (opcode >= (1 << preShift)) { //参考Symtab类的enterBinop方法
code.emitop0(opcode >> preShift);
opcode = opcode & 0xFF;
}
}
DEBUG.P("opcode="+code.mnem(opcode));
if (opcode >= ifeq && opcode <= if_acmpne ||
opcode == if_acmp_null || opcode == if_acmp_nonnull) {
return items.makeCondItem(opcode);
} else {
code.emitop0(opcode);
return items.makeStackItem(optype.restype);
}
}finally{//我加上的
DEBUG.P(0,this,"completeBinop(3)");
}
}
public void visitTypeCast(JCTypeCast tree) {
DEBUG.P(this,"visitTypeCast(1)");
result = genExpr(tree.expr, tree.clazz.type).load();
// Additional code is only needed if we cast to a reference type
// which is not statically a supertype of the expression's type.
// For basic types, the coerce(...) in genExpr(...) will do
// the conversion.
if (tree.clazz.type.tag > lastBaseTag &&
types.asSuper(tree.expr.type, tree.clazz.type.tsym) == null) {
code.emitop2(checkcast, makeRef(tree.pos(), tree.clazz.type));
}
DEBUG.P(0,this,"visitTypeCast(1)");
}
public void visitWildcard(JCWildcard tree) {
throw new AssertionError(this.getClass().getName());
}
public void visitTypeTest(JCInstanceOf tree) {
genExpr(tree.expr, tree.expr.type).load();
code.emitop2(instanceof_, makeRef(tree.pos(), tree.clazz.type));
result = items.makeStackItem(syms.booleanType);
}
public void visitIndexed(JCArrayAccess tree) {
genExpr(tree.indexed, tree.indexed.type).load();
genExpr(tree.index, syms.intType).load();
result = items.makeIndexedItem(tree.type);
}
public void visitIdent(JCIdent tree) {
DEBUG.P(this,"visitIdent(1)");
Symbol sym = tree.sym;
DEBUG.P("tree.name="+tree.name);
DEBUG.P("sym="+sym);
DEBUG.P("sym.flags()="+Flags.toString(sym.flags()));
DEBUG.P("sym.kind="+Kinds.toString(sym.kind));
DEBUG.P("sym.owner="+sym.owner);
if(sym.owner!=null) DEBUG.P("sym.owner.kind="+Kinds.toString(sym.owner.kind));
if (tree.name == names._this || tree.name == names._super) {
Item res = tree.name == names._this
? items.makeThisItem()
: items.makeSuperItem();
if (sym.kind == MTH) {
// Generate code to address the constructor.
res.load();
//这里为true，说明不是一个virtual调用，而是Invokespecial
//因为当前面两个if条件都为true时，源代码中要么是this()要么是super()
res = items.makeMemberItem(sym, true);
}
result = res;
} else if (sym.kind == VAR && sym.owner.kind == MTH) {
//本地变量
result = items.makeLocalItem((VarSymbol)sym);
} else if ((sym.flags() & STATIC) != 0) {
//类字段
if (!isAccessSuper(env.enclMethod))
sym = binaryQualifier(sym, env.enclClass.type);
result = items.makeStaticItem(sym);
} else {
//实例字段
items.makeThisItem().load();
sym = binaryQualifier(sym, env.enclClass.type);
result = items.makeMemberItem(sym, (sym.flags() & PRIVATE) != 0);
}
DEBUG.P(0,this,"visitIdent(1)");
}
public void visitSelect(JCFieldAccess tree) {
DEBUG.P(this,"visitSelect(1)");
Symbol sym = tree.sym;
DEBUG.P("tree.name="+tree.name);
if (tree.name == names._class) {
assert target.hasClassLiterals();
code.emitop2(ldc2, makeRef(tree.pos(), tree.selected.type));
result = items.makeStackItem(pt);
return;
}
Symbol ssym = TreeInfo.symbol(tree.selected);
DEBUG.P("ssym="+ssym);
if(ssym != null) {
DEBUG.P("ssym.kind="+Kinds.toString(ssym.kind));
DEBUG.P("ssym.name="+ssym.name);
}
// Are we selecting via super?
boolean selectSuper =
ssym != null && (ssym.kind == TYP || ssym.name == names._super);
DEBUG.P("");
DEBUG.P("selectSuper="+selectSuper);
// Are we accessing a member of the superclass in an access method
// resulting from a qualified super?
boolean accessSuper = isAccessSuper(env.enclMethod);
DEBUG.P("accessSuper="+accessSuper);
Item base = (selectSuper)
? items.makeSuperItem()
: genExpr(tree.selected, tree.selected.type);
DEBUG.P("");
DEBUG.P("sym.kind="+Kinds.toString(sym.kind));
if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
// We are seeing a variable that is constant but its selecting
// expression is not.
if ((sym.flags() & STATIC) != 0) {
if (!selectSuper && (ssym == null || ssym.kind != TYP))
base = base.load();
base.drop();
} else {
base.load();
genNullCheck(tree.selected.pos());
}
result = items.
makeImmediateItem(sym.type, ((VarSymbol) sym).getConstValue());
} else {
if (!accessSuper)
sym = binaryQualifier(sym, tree.selected.type);
if ((sym.flags() & STATIC) != 0) {
if (!selectSuper && (ssym == null || ssym.kind != TYP))
base = base.load();
base.drop();
result = items.makeStaticItem(sym);
} else {
base.load();
if (sym == syms.lengthVar) {
code.emitop0(arraylength);
result = items.makeStackItem(syms.intType);
} else {
result = items.
makeMemberItem(sym,
(sym.flags() & PRIVATE) != 0 ||
selectSuper || accessSuper);
}
}
}
DEBUG.P(0,this,"visitSelect(1)");
}
public void visitLiteral(JCLiteral tree) {
DEBUG.P(this,"visitLiteral(1)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.type.tag="+TypeTags.toString(tree.type.tag));
if (tree.type.tag == TypeTags.BOT) {
code.emitop0(aconst_null);
DEBUG.P("types.dimensions(pt)="+types.dimensions(pt));
if (types.dimensions(pt) > 1) {//大于等于二维数组时条件才为true
//给多维数组变量赋null时，先把null转换成多维数组类型
code.emitop2(checkcast, makeRef(tree.pos(), pt));
result = items.makeStackItem(pt);
} else {
//一维数组不用转换
result = items.makeStackItem(tree.type);
}
}
else
result = items.makeImmediateItem(tree.type, tree.value);
DEBUG.P(0,this,"visitLiteral(1)");
}
public void visitLetExpr(LetExpr tree) {
DEBUG.P(this,"visitLetExpr(1)");
int limit = code.nextreg;
genStats(tree.defs, env);
result = genExpr(tree.expr, tree.expr.type).load();
code.endScopes(limit);
DEBUG.P(0,this,"visitLetExpr(1)");
}
/* ************************************************************************
* main method
*************************************************************************/
/** Generate code for a class definition.
* @param env The attribution environment that belongs to the
* outermost class containing this class definition.
* We need this for resolving some additional symbols.
* @param cdef The tree representing the class definition.
* @return True if code is generated with no errors.
*/
public boolean genClass(Env<AttrContext> env, JCClassDecl cdef) {
DEBUG.P(this,"genClass(2) 正在生成字节码......");
DEBUG.P("cdef="+cdef);
DEBUG.P("env="+env);
try {
attrEnv = env;
ClassSymbol c = cdef.sym;
this.toplevel = env.toplevel;
this.endPositions = toplevel.endPositions;
DEBUG.P("generateIproxies="+generateIproxies);
DEBUG.P("allowGenerics="+allowGenerics);
DEBUG.P("c="+c);
DEBUG.P("c.flags()="+Flags.toString(c.flags()));
// If this is a class definition requiring Miranda methods,
// add them.
if (generateIproxies && //jdk1.1与jdk1.0才需要
(c.flags() & (INTERFACE|ABSTRACT)) == ABSTRACT
&& !allowGenerics // no Miranda methods available with generics
)
implementInterfaceMethods(c);
cdef.defs = normalizeDefs(cdef.defs, c);
//经过normalizeDefs(cdef.defs, c)后，类体(defs)中只包含方法(构造方法和非构造方法)
//内部类或内部接口也不包含在类体(defs)中
DEBUG.P("cdef.defs(规范化后的类体)="+cdef.defs);
c.pool = pool;
pool.reset();
Env<GenContext> localEnv =
new Env<GenContext>(cdef, new GenContext());
localEnv.toplevel = env.toplevel;
localEnv.enclClass = cdef;
int myMethodCount=1;
DEBUG.P(2);DEBUG.P("开始为每一个方法生成字节码...(方法总个数: "+cdef.defs.size()+")");
for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
DEBUG.P("第 "+myMethodCount+" 个方法开始...");
genDef(l.head, localEnv);
DEBUG.P("第 "+myMethodCount+" 个方法结束...");
myMethodCount++;DEBUG.P(2);
}
if (pool.numEntries() > Pool.MAX_ENTRIES) {
log.error(cdef.pos(), "limit.pool");
nerrs++;
}
if (nerrs != 0) {
// if errors, discard code
for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
if (l.head.tag == JCTree.METHODDEF)
((JCMethodDecl) l.head).sym.code = null;
}
}
cdef.defs = List.nil(); // discard trees
return nerrs == 0;
} finally {
// note: this method does NOT support recursion.
attrEnv = null;
this.env = null;
toplevel = null;
endPositions = null;
nerrs = 0;
DEBUG.P(2,this,"genClass(2)");
}
}
/* ************************************************************************
* Auxiliary classes
*************************************************************************/
/** An abstract class for finalizer generation.
*/
abstract class GenFinalizer {
/** Generate code to clean up when unwinding. */
abstract void gen();
/** Generate code to clean up at last. */
abstract void genLast();
/** Does this finalizer have some nontrivial cleanup to perform? */
boolean hasFinalizer() { return true; }
}
/** code generation contexts,
* to be used as type parameter for environments.
*/
static class GenContext {
/** A chain for all unresolved jumps that exit the current environment.
*/
Chain exit = null;
/** A chain for all unresolved jumps that continue in the
* current environment.
*/
Chain cont = null;
/** A closure that generates the finalizer of the current environment.
* Only set for Synchronized and Try contexts.
*/
GenFinalizer finalize = null;
/** Is this a switch statement? If so, allocate registers
* even when the variable declaration is unreachable.
*/
boolean isSwitch = false;
/** A list buffer containing all gaps in the finalizer range,
* where a catch all exception should not apply.
*/
ListBuffer<Integer> gaps = null;
/** Add given chain to exit chain.
*/
void addExit(Chain c) {
exit = Code.mergeChains(c, exit);
}
/** Add given chain to cont chain.
*/
void addCont(Chain c) {
cont = Code.mergeChains(c, cont);
}
//我加上的
public String toString() {
return "GC[gaps="+gaps+", exit="+exit+", cont="+cont+", isSwitch="+isSwitch+", finalize="+finalize+"]";
}
}
}