/*
* @(#)Attr.java 1.224 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.comp;
import java.util.*;
import java.util.Set;
import javax.lang.model.element.ElementKind;
import javax.tools.JavaFileObject;
import com.sun.tools.javac.code.*;
import com.sun.tools.javac.jvm.*;
import com.sun.tools.javac.tree.*;
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.jvm.Target;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.tree.JCTree.*;
import com.sun.tools.javac.code.Type.*;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.TreeVisitor;
import com.sun.source.util.SimpleTreeVisitor;
import static com.sun.tools.javac.code.Flags.*;
import static com.sun.tools.javac.code.Kinds.*;
import static com.sun.tools.javac.code.TypeTags.*;
/** This is the main context-dependent analysis phase in GJC. It
* encompasses name resolution, type checking and constant folding as
* subtasks. Some subtasks involve auxiliary classes.
* @see Check
* @see Resolve
* @see ConstFold
* @see Infer
*
* <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("@(#)Attr.java 1.224 07/03/21")
//只有visitCase, visitCatch, visitLetExpr, visitModifiers, visitTopLevel, visitTypeBoundKind没有覆盖
public class Attr extends JCTree.Visitor {
private static my.Debug DEBUG=new my.Debug(my.Debug.Attr);//我加上的
protected static final Context.Key<Attr> attrKey =
new Context.Key<Attr>();
final Name.Table names;
final Log log;
final Symtab syms;
final Resolve rs;
final Check chk;
final MemberEnter memberEnter;
final TreeMaker make;
final ConstFold cfolder;
final Enter enter;
final Target target;
final Types types;
final Annotate annotate;
public static Attr instance(Context context) {
Attr instance = context.get(attrKey);
if (instance == null)
instance = new Attr(context);
return instance;
}
protected Attr(Context context) {
DEBUG.P(this,"Attr(1)");
context.put(attrKey, this);
names = Name.Table.instance(context);
log = Log.instance(context);
syms = Symtab.instance(context);
rs = Resolve.instance(context);
chk = Check.instance(context);
memberEnter = MemberEnter.instance(context);
make = TreeMaker.instance(context);
enter = Enter.instance(context);
cfolder = ConstFold.instance(context);
target = Target.instance(context);
types = Types.instance(context);
annotate = Annotate.instance(context);
Options options = Options.instance(context);
Source source = Source.instance(context);
allowGenerics = source.allowGenerics();
allowVarargs = source.allowVarargs();
allowEnums = source.allowEnums();
allowBoxing = source.allowBoxing();
allowCovariantReturns = source.allowCovariantReturns();
allowAnonOuterThis = source.allowAnonOuterThis();
relax = (options.get("-retrofit") != null ||
options.get("-relax") != null);
useBeforeDeclarationWarning = options.get("useBeforeDeclarationWarning") != null;
DEBUG.P(0,this,"Attr(1)");
}
/** Switch: relax some constraints for retrofit mode.
*/
boolean relax;
/** Switch: support generics?
*/
boolean allowGenerics;
/** Switch: allow variable-arity methods.
*/
boolean allowVarargs;
/** Switch: support enums?
*/
boolean allowEnums;
/** Switch: support boxing and unboxing?
*/
boolean allowBoxing;
/** Switch: support covariant result types?
*/
boolean allowCovariantReturns;
/** Switch: allow references to surrounding object from anonymous
* objects during constructor call?
*/
boolean allowAnonOuterThis;
/**
* Switch: warn about use of variable before declaration?
* RFE: 6425594
*/
boolean useBeforeDeclarationWarning;
/** Check kind and type of given tree against protokind and prototype.
* If check succeeds, store type in tree and return it.
* If check fails, store errType in tree and return it.
* No checks are performed if the prototype is a method type.
* Its not necessary in this case since we know that kind and type
* are correct.
*
* @param tree The tree whose kind and type is checked
* @param owntype The computed type of the tree
* @param ownkind The computed kind of the tree
* @param pkind The expected kind (or: protokind) of the tree
* @param pt The expected type (or: prototype) of the tree
*/
Type check(JCTree tree, Type owntype, int ownkind, int pkind, Type pt) {
DEBUG.P(this,"check(5)");
DEBUG.P("tree.type="+tree.type);
DEBUG.P("ownkind="+Kinds.toString(ownkind));
DEBUG.P("owntype.tag="+TypeTags.toString(owntype.tag));
DEBUG.P("pkind="+Kinds.toString(pkind));
DEBUG.P("pt.tag="+TypeTags.toString(pt.tag));
if (owntype.tag != ERROR && pt.tag != METHOD && pt.tag != FORALL) {
//如果ownkind所代表的Kinds在pkind中没有，则报错
/*比如：如果ownkind是VAR,而pkind是PCK与TYP
bin\mysrc\my\test\Test.java:3: 意外的类型
需要： 类、软件包
找到： 变量
*/
//ownkind只能代表单个kind，而pkind可以是多个kind的复合
//从下面的kindName与kindNames也可能看出来
if ((ownkind & ~pkind) == 0) {
owntype = chk.checkType(tree.pos(), owntype, pt);
} else {
log.error(tree.pos(), "unexpected.type",
Resolve.kindNames(pkind),
Resolve.kindName(ownkind));
owntype = syms.errType;
}
}
tree.type = owntype;
DEBUG.P(0,this,"check(5)");
return owntype;
}
/** Is given blank final variable assignable, i.e. in a scope where it
* may be assigned to even though it is final?
* @param v The blank final variable.
* @param env The current environment.
*/
boolean isAssignableAsBlankFinal(VarSymbol v, Env<AttrContext> env) {
try {//我加上的
DEBUG.P(this,"isAssignableAsBlankFinal(2)");
Symbol owner = env.info.scope.owner;
DEBUG.P("v="+v);
DEBUG.P("v.flags()="+Flags.toString(v.flags()));
DEBUG.P("v.owner="+v.owner);
DEBUG.P("owner="+owner);
DEBUG.P("owner.flags()="+Flags.toString(owner.flags()));
// owner refers to the innermost variable, method or
// initializer block declaration at this point.
return
v.owner == owner
||
((owner.name == names.init || // i.e. we are in a constructor
owner.kind == VAR || // i.e. we are in a variable initializer
(owner.flags() & BLOCK) != 0) // i.e. we are in an initializer block
&&
v.owner == owner.owner
&&
((v.flags() & STATIC) != 0) == Resolve.isStatic(env));
}finally{//我加上的
DEBUG.P(0,this,"isAssignableAsBlankFinal(2)");
}
}
/** Check that variable can be assigned to.
* @param pos The current source code position.
* @param v The assigned varaible
* @param base If the variable is referred to in a Select, the part
* to the left of the `.', null otherwise.
* @param env The current environment.
*/
void checkAssignable(DiagnosticPosition pos, VarSymbol v, JCTree base, Env<AttrContext> env) {
DEBUG.P(this,"checkAssignable(4)");
DEBUG.P("v="+v);
DEBUG.P("v.flags()="+Flags.toString(v.flags()));
DEBUG.P("base="+base);
if(base != null) {
DEBUG.P("base.tag="+base.myTreeTag());
DEBUG.P("TreeInfo.name(base)="+TreeInfo.name(base));
}
if ((v.flags() & FINAL) != 0 &&
((v.flags() & HASINIT) != 0
||
!((base == null ||
(base.tag == JCTree.IDENT && TreeInfo.name(base) == names._this)) &&
isAssignableAsBlankFinal(v, env)))) {
log.error(pos, "cant.assign.val.to.final.var", v);
}
DEBUG.P(0,this,"checkAssignable(4)");
}
/** Does tree represent a static reference to an identifier?
* It is assumed that tree is either a SELECT or an IDENT.
* We have to weed out selects from non-type names here.
* @param tree The candidate tree.
*/
boolean isStaticReference(JCTree tree) {
if (tree.tag == JCTree.SELECT) {
Symbol lsym = TreeInfo.symbol(((JCFieldAccess) tree).selected);
if (lsym == null || lsym.kind != TYP) {
return false;
}
}
return true;
}
/** Is this symbol a type?
*/
static boolean isType(Symbol sym) {
return sym != null && sym.kind == TYP;
}
/** The current `this' symbol.
* @param env The current environment.
*/
Symbol thisSym(DiagnosticPosition pos, Env<AttrContext> env) {
try {//我加上的
DEBUG.P(this,"thisSym(2)");
return rs.resolveSelf(pos, env, env.enclClass.sym, names._this);
}finally{//我加上的
DEBUG.P(0,this,"thisSym(2)");
}
}
/** Attribute a parsed identifier.
* @param tree Parsed identifier name
* @param topLevel The toplevel to use
*/
public Symbol attribIdent(JCTree tree, JCCompilationUnit topLevel) {
Env<AttrContext> localEnv = enter.topLevelEnv(topLevel);
localEnv.enclClass = make.ClassDef(make.Modifiers(0),
syms.errSymbol.name,
null, null, null, null);
localEnv.enclClass.sym = syms.errSymbol;
return tree.accept(identAttributer, localEnv);
}
// where
private TreeVisitor<Symbol,Env<AttrContext>> identAttributer = new IdentAttributer();
private class IdentAttributer extends SimpleTreeVisitor<Symbol,Env<AttrContext>> {
@Override
public Symbol visitMemberSelect(MemberSelectTree node, Env<AttrContext> env) {
Symbol site = visit(node.getExpression(), env);
if (site.kind == ERR)
return site;
Name name = (Name)node.getIdentifier();
if (site.kind == PCK) {
env.toplevel.packge = (PackageSymbol)site;
return rs.findIdentInPackage(env, (TypeSymbol)site, name, TYP | PCK);
} else {
env.enclClass.sym = (ClassSymbol)site;
return rs.findMemberType(env, site.asType(), name, (TypeSymbol)site);
}
}
@Override
public Symbol visitIdentifier(IdentifierTree node, Env<AttrContext> env) {
return rs.findIdent(env, (Name)node.getName(), TYP | PCK);
}
}
public Type coerce(Type etype, Type ttype) {
return cfolder.coerce(etype, ttype);
}
public Type attribType(JCTree node, TypeSymbol sym) {
Env<AttrContext> env = enter.typeEnvs.get(sym);
Env<AttrContext> localEnv = env.dup(node, env.info.dup());
return attribTree(node, localEnv, Kinds.TYP, Type.noType);
}
public Env<AttrContext> attribExprToTree(JCTree expr, Env<AttrContext> env, JCTree tree) {
breakTree = tree;
JavaFileObject prev = log.useSource(null);
try {
attribExpr(expr, env);
} catch (BreakAttr b) {
return b.env;
} finally {
breakTree = null;
log.useSource(prev);
}
return env;
}
public Env<AttrContext> attribStatToTree(JCTree stmt, Env<AttrContext> env, JCTree tree) {
breakTree = tree;
JavaFileObject prev = log.useSource(null);
try {
attribStat(stmt, env);
} catch (BreakAttr b) {
return b.env;
} finally {
breakTree = null;
log.useSource(prev);
}
return env;
}
private JCTree breakTree = null;
private static class BreakAttr extends RuntimeException {
static final long serialVersionUID = -6924771130405446405L;
private Env<AttrContext> env;
private BreakAttr(Env<AttrContext> env) {
this.env = env;
}
}
/* ************************************************************************
* Visitor methods
*************************************************************************/
//
/** Visitor argument: the current environment.
*/
Env<AttrContext> env;
/** Visitor argument: the currently expected proto-kind.
*/
int pkind;
/** Visitor argument: the currently expected proto-type.
*/
Type pt;
/** Visitor result: the computed type.
*/
Type result;
/** Visitor method: attribute a tree, catching any completion failure
* exceptions. Return the tree's type.
*
* @param tree The tree to be visited.
* @param env The environment visitor argument.
* @param pkind The protokind visitor argument.
* @param pt The prototype visitor argument.
*/
Type attribTree(JCTree tree, Env<AttrContext> env, int pkind, Type pt) {
DEBUG.P(this,"attribTree(4)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.tag="+tree.myTreeTag());
//DEBUG.P("env="+env);
DEBUG.P("pkind="+Kinds.toString(pkind));
DEBUG.P("pt="+pt);
DEBUG.P("pt.tag="+TypeTags.toString(pt.tag));
Env<AttrContext> prevEnv = this.env;
int prevPkind = this.pkind;
Type prevPt = this.pt;
try {
this.env = env;
this.pkind = pkind;
this.pt = pt;
tree.accept(this);
if (tree == breakTree) //当breakTree==tree==null时
throw new BreakAttr(env);//是java.lang.RuntimeException的子类
return result;
} catch (CompletionFailure ex) {
tree.type = syms.errType;
return chk.completionError(tree.pos(), ex);
} finally {
this.env = prevEnv;
this.pkind = prevPkind;
this.pt = prevPt;
DEBUG.P("pkind="+Kinds.toString(pkind));
DEBUG.P("tree ="+tree);
DEBUG.P("tree.tag ="+tree.myTreeTag());
if(tree.type!=null) {
DEBUG.P("tree.type ="+tree.type);
DEBUG.P("tree.type.tsym ="+tree.type.tsym);
if(tree.type.tsym!=null)
DEBUG.P("tree.type.tsym.type="+tree.type.tsym.type);
} else
DEBUG.P("tree.type=null");
DEBUG.P(0,this,"attribTree(4)");
}
}
/** Derived visitor method: attribute an expression tree.
*/
public Type attribExpr(JCTree tree, Env<AttrContext> env, Type pt) {
try {//我加上的
DEBUG.P(this,"attribExpr(3)");
return attribTree(tree, env, VAL, pt.tag != ERROR ? pt : Type.noType);
}finally{//我加上的
DEBUG.P(0,this,"attribExpr(3)");
}
}
/** Derived visitor method: attribute an expression tree with
* no constraints on the computed type.
*/
Type attribExpr(JCTree tree, Env<AttrContext> env) {
try {//我加上的
DEBUG.P(this,"attribExpr(2)");
return attribTree(tree, env, VAL, Type.noType);
}finally{//我加上的
DEBUG.P(0,this,"attribExpr(2)");
}
}
/** Derived visitor method: attribute a type tree.
*/
Type attribType(JCTree tree, Env<AttrContext> env) {
DEBUG.P(this,"attribType(2)");
Type result = attribTree(tree, env, TYP, Type.noType);
//DEBUG.P("result="+result);
//DEBUG.P("result.tag="+TypeTags.toString(result.tag));
DEBUG.P(0,this,"attribType(2)");
return result;
}
/** Derived visitor method: attribute a statement or definition tree.
*/
public Type attribStat(JCTree tree, Env<AttrContext> env) {
try {//我加上的
DEBUG.P(this,"attribStat(2)");
return attribTree(tree, env, NIL, Type.noType);
}finally{//我加上的
DEBUG.P(1,this,"attribStat(2)");
}
}
/** Attribute a list of expressions, returning a list of types.
*/
List<Type> attribExprs(List<JCExpression> trees, Env<AttrContext> env, Type pt) {
DEBUG.P(this,"attribExprs(3)");
ListBuffer<Type> ts = new ListBuffer<Type>();
for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail)
ts.append(attribExpr(l.head, env, pt));
DEBUG.P(0,this,"attribExprs(3)");
return ts.toList();
}
/** Attribute a list of statements, returning nothing.
*/
<T extends JCTree> void attribStats(List<T> trees, Env<AttrContext> env) {
DEBUG.P(this,"attribStats(2)");
for (List<T> l = trees; l.nonEmpty(); l = l.tail)
attribStat(l.head, env);
DEBUG.P(0,this,"attribStats(2)");
}
/** Attribute the arguments in a method call, returning a list of types.
*/
List<Type> attribArgs(List<JCExpression> trees, Env<AttrContext> env) {
try {//我加上的
DEBUG.P(this,"attribArgs(2)");
DEBUG.P("trees="+trees);
//DEBUG.P("env="+env);
ListBuffer<Type> argtypes = new ListBuffer<Type>();
for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail)
argtypes.append(chk.checkNonVoid(
l.head.pos(), types.upperBound(attribTree(l.head, env, VAL, Infer.anyPoly))));
return argtypes.toList();
}finally{//我加上的
DEBUG.P(0,this,"attribArgs(2)");
}
}
/** Attribute a type argument list, returning a list of types.
*/
List<Type> attribTypes(List<JCExpression> trees, Env<AttrContext> env) {
DEBUG.P(this,"attribTypes(2)");
DEBUG.P("trees="+trees);
//DEBUG.P("env="+env);
ListBuffer<Type> argtypes = new ListBuffer<Type>();
for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail)
argtypes.append(chk.checkRefType(l.head.pos(), attribType(l.head, env)));
DEBUG.P(0,this,"attribTypes(2)");
return argtypes.toList();
}
//
/**
* Attribute type variables (of generic classes or methods).
* Compound types are attributed later in attribBounds.
* @param typarams the type variables to enter
* @param env the current environment
*/
//b10新增
void attribTypeVariables(List<JCTypeParameter> typarams, Env<AttrContext> env) {
DEBUG.P(this,"attribTypeVariables(2)");
DEBUG.P("typarams="+typarams);
DEBUG.P("env="+env);
/*注意:
像class Test<S,P extends V, V extends InterfaceTest,T extends ExtendsTest,E extends ExtendsTest&InterfaceTest>
这样的定义是合法的，
虽然V在P之后，但P 先extends V也不会报错，
因为所有的类型变量(这里是S, P, V, T, E)，在
com.sun.tools.javac.comp.Enter===>visitTypeParameter(JCTypeParameter tree)
方法中事先已加入与Test对应的Env里，如下所示为上面两个DEBUG.P()的结果:
typarams=S,P extends V,V extends InterfaceTest,T extends ExtendsTest,E extends ExtendsTest & InterfaceTest
env=Env(TK=CLASS EC=)[AttrContext[Scope[(nelems=5 owner=Test)E, T, V, P, S]],outer=Env(TK=COMPILATION_UNIT EC=)[AttrContext[Scope[(nelems=3 owner=test)Test, ExtendsTest, InterfaceTest]]]]
当要生成类型变量P的bound时，因为JCTypeParameter.bounds=V，然后
在env中查找，发现V在env的Scope存在，所以是可以超前引用V的，
这主要是因为类型变量的解析和类型变量的bound的解析是分先后两个
阶段进行的，但是把“P extends V”改成“P extends V2”，就会
报“找不到符号”这个错误，因为V2不在env中，其他地方也找不到。
*/
for (JCTypeParameter tvar : typarams) {
TypeVar a = (TypeVar)tvar.type;
DEBUG.P("a.tsym.name="+a.tsym.name);
DEBUG.P("a.bound="+a.bound);
DEBUG.P("tvar="+tvar);
DEBUG.P("tvar.bounds="+tvar.bounds);
if (!tvar.bounds.isEmpty()) {
List<Type> bounds = List.of(attribType(tvar.bounds.head, env));
for (JCExpression bound : tvar.bounds.tail)
bounds = bounds.prepend(attribType(bound, env));
DEBUG.P("bounds="+bounds);
DEBUG.P("bounds.reverse()="+bounds.reverse());
types.setBounds(a, bounds.reverse());
} else {
// if no bounds are given, assume a single bound of
// java.lang.Object.
types.setBounds(a, List.of(syms.objectType));
}
DEBUG.P("a.bound="+a.bound);DEBUG.P("");
}
for (JCTypeParameter tvar : typarams)
chk.checkNonCyclic(tvar.pos(), (TypeVar)tvar.type);
attribStats(typarams, env);
DEBUG.P(0,this,"attribTypeVariables(2)");
}
//对形如:E extends ExtendsTest&InterfaceTest这样的类型变量进行attribClass
void attribBounds(List<JCTypeParameter> typarams) {
DEBUG.P(this,"attribBounds(1)");
DEBUG.P("typarams="+typarams);
for (JCTypeParameter typaram : typarams) {
Type bound = typaram.type.getUpperBound();
DEBUG.P("");
DEBUG.P("typaram="+typaram);
DEBUG.P("bound="+bound);
if (bound != null) DEBUG.P("bound.tsym.className="+bound.tsym.getClass().getName());
if (bound != null && bound.tsym instanceof ClassSymbol) {
ClassSymbol c = (ClassSymbol)bound.tsym;
DEBUG.P("bound.tsym.flags_field="+Flags.toString(c.flags_field));
if ((c.flags_field & COMPOUND) != 0) {
assert (c.flags_field & UNATTRIBUTED) != 0 : c;
attribClass(typaram.pos(), c);
}
}
}
DEBUG.P(1,this,"attribBounds(1)");
}
/**
* Attribute the type references in a list of annotations.
*/
void attribAnnotationTypes(List<JCAnnotation> annotations,
Env<AttrContext> env) {
DEBUG.P(this,"attribAnnotationTypes(2)");
DEBUG.P("env="+env);
DEBUG.P("annotations="+annotations);
for (List<JCAnnotation> al = annotations; al.nonEmpty(); al = al.tail) {
JCAnnotation a = al.head;
attribType(a.annotationType, env);
}
DEBUG.P(0,this,"attribAnnotationTypes(2)");
}
// <editor-fold defaultstate="collapsed">
/** Attribute type reference in an `extends' or `implements' clause.
*
* @param tree The tree making up the type reference.
* @param env The environment current at the reference.
* @param classExpected true if only a class is expected here.
* @param interfaceExpected true if only an interface is expected here.
*/
/*
Type attribBase(JCTree tree,
Env<AttrContext> env,
boolean classExpected,
boolean interfaceExpected,
boolean checkExtensible) {
try {//我加上的
DEBUG.P(this,"attribBase(5)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.getKind()="+tree.getKind());
DEBUG.P("env="+env);
DEBUG.P("classExpected="+classExpected);
DEBUG.P("interfaceExpected="+interfaceExpected);
DEBUG.P("checkExtensible="+checkExtensible);
Type t = attribType(tree, env);
DEBUG.P("t.tag="+TypeTags.toString(t.tag));
if (t.tag == TYPEVAR && !classExpected && !interfaceExpected) {
// check that type variable is already visible
if (t.getUpperBound() == null) {
log.error(tree.pos(), "illegal.forward.ref");
return syms.errType;
}
} else {
t = chk.checkClassType(tree.pos(), t, checkExtensible|!allowGenerics);
}
if (interfaceExpected && (t.tsym.flags() & INTERFACE) == 0) {
log.error(tree.pos(), "intf.expected.here");
// return errType is necessary since otherwise there might
// be undetected cycles which cause attribution to loop
return syms.errType;
} else if (checkExtensible &&
classExpected &&
(t.tsym.flags() & INTERFACE) != 0) {
log.error(tree.pos(), "no.intf.expected.here");
return syms.errType;
}
if (checkExtensible &&
((t.tsym.flags() & FINAL) != 0)) {
log.error(tree.pos(),
"cant.inherit.from.final", t.tsym);
}
chk.checkNonCyclic(tree.pos(), t);
return t;
}finally{//我加上的
DEBUG.P(0,this,"attribBase(5)");
}
}*/
// </editor-fold>
/** Attribute type reference in an `extends' or `implements' clause.
*
* @param tree The tree making up the type reference.
* @param env The environment current at the reference.
* @param classExpected true if only a class is expected here.
* @param interfaceExpected true if only an interface is expected here.
*/
//b10
Type attribBase(JCTree tree,
Env<AttrContext> env,
boolean classExpected,
boolean interfaceExpected,
boolean checkExtensible) {
try {//我加上的
DEBUG.P(this,"attribBase(5)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.tag="+tree.myTreeTag());
DEBUG.P("env="+env);
DEBUG.P("classExpected="+classExpected);
DEBUG.P("interfaceExpected="+interfaceExpected);
DEBUG.P("checkExtensible="+checkExtensible);
Type t = attribType(tree, env);
DEBUG.P("t.tag="+TypeTags.toString(t.tag));
return checkBase(t, tree, env, classExpected, interfaceExpected, checkExtensible);
}finally{//我加上的
DEBUG.P(0,this,"attribBase(5)");
}
}
//b10
Type checkBase(Type t,
JCTree tree,
Env<AttrContext> env,
boolean classExpected,
boolean interfaceExpected,
boolean checkExtensible) {
try {//我加上的
DEBUG.P(this,"checkBase(6)");
DEBUG.P("t.tag="+TypeTags.toString(t.tag));
DEBUG.P("tree="+tree);
DEBUG.P("env="+env);
DEBUG.P("classExpected="+classExpected);
DEBUG.P("interfaceExpected="+interfaceExpected);
DEBUG.P("checkExtensible="+checkExtensible);
if (t.tag == TYPEVAR && !classExpected && !interfaceExpected) {
DEBUG.P("t.getUpperBound()="+t.getUpperBound());
// check that type variable is already visible
if (t.getUpperBound() == null) {
log.error(tree.pos(), "illegal.forward.ref");
return syms.errType;
}
} else {
t = chk.checkClassType(tree.pos(), t, checkExtensible|!allowGenerics);
}
if (interfaceExpected && (t.tsym.flags() & INTERFACE) == 0) {
/*错误例子:
bin\mysrc\my\test\Test.java:8: 此处需要接口
public class Test<S,T extends ExtendsTest,E extends ExtendsTest & MyInterfaceA>
extends my.ExtendsTest.MyInnerClassStatic implements ExtendsTest {
^
*/
log.error(tree.pos(), "intf.expected.here");
// return errType is necessary since otherwise there might
// be undetected cycles which cause attribution to loop
return syms.errType;
} else if (checkExtensible &&
classExpected &&
(t.tsym.flags() & INTERFACE) != 0) {
/*src/my/test/EnterTest.java:24: 此处不需要接口
public class EnterTest<T,S> extends EnterTestInterfaceA implements EnterTestInterfaceA,EnterTestInterfaceB {
^
*/
log.error(tree.pos(), "no.intf.expected.here");
return syms.errType;
}
if (checkExtensible &&
((t.tsym.flags() & FINAL) != 0)) {
/*
src/my/test/EnterTest.java:27: 无法从最终 my.test.EnterTestFinalSupertype 进行继承
public class EnterTest<T,S> extends EnterTestFinalSupertype {
^
*/
log.error(tree.pos(),
"cant.inherit.from.final", t.tsym);
}
chk.checkNonCyclic(tree.pos(), t);
return t;
}finally{//我加上的
DEBUG.P(0,this,"checkBase(6)");
}
}
public void visitClassDef(JCClassDecl tree) {
DEBUG.P(this,"visitClassDef(1)");
DEBUG.P("tree.sym="+tree.sym);
DEBUG.P("env.info.scope.owner.kind="+Kinds.toString(env.info.scope.owner.kind));
// Local classes have not been entered yet, so we need to do it now:
if ((env.info.scope.owner.kind & (VAR | MTH)) != 0)
enter.classEnter(tree, env);
ClassSymbol c = tree.sym;
DEBUG.P("enter.classEnter 结束 c="+c);
if (c == null) {
// exit in case something drastic went wrong during enter.
result = null;
} else {
// make sure class has been completed:
c.complete();
// If this class appears as an anonymous class
// in a superclass constructor call where
// no explicit outer instance is given,
// disable implicit outer instance from being passed.
// (This would be an illegal access to "this before super").
DEBUG.P("env.info.isSelfCall="+env.info.isSelfCall);
DEBUG.P("env.tree.tag="+env.tree.myTreeTag());
if(env.tree.tag == JCTree.NEWCLASS)
DEBUG.P("env.tree.encl="+((JCNewClass) env.tree).encl);
if (env.info.isSelfCall &&
env.tree.tag == JCTree.NEWCLASS &&
((JCNewClass) env.tree).encl == null)
{
c.flags_field |= NOOUTERTHIS;
}
DEBUG.P("c.flags_field="+Flags.toString(c.flags_field));
attribClass(tree.pos(), c);
result = tree.type = c.type;
}
DEBUG.P(0,this,"visitClassDef(1)");
}
public void visitMethodDef(JCMethodDecl tree) {
DEBUG.P(this,"visitMethodDef(JCMethodDecl tree)");
DEBUG.P("tree.sym="+tree.sym);
MethodSymbol m = tree.sym;
DEBUG.P("env.info.lint="+env.info.lint);
Lint lint = env.info.lint.augment(m.attributes_field, m.flags());
DEBUG.P("lint="+lint);
Lint prevLint = chk.setLint(lint);
try {
chk.checkDeprecatedAnnotation(tree.pos(), m);
//COMPOUND类型会对应一个ClassSymbol
//在attribBounds必须对这个ClassSymbol进行attribClass
attribBounds(tree.typarams);
// If we override any other methods, check that we do so properly.
// JLS ???
chk.checkOverride(tree, m);
// Create a new environment with local scope
// for attributing the method.
Env<AttrContext> localEnv = memberEnter.methodEnv(tree, env);
localEnv.info.lint = lint;
// Enter all type parameters into the local method scope.
for (List<JCTypeParameter> l = tree.typarams; l.nonEmpty(); l = l.tail)
localEnv.info.scope.enterIfAbsent(l.head.type.tsym);
ClassSymbol owner = env.enclClass.sym;
if ((owner.flags() & ANNOTATION) != 0 &&
tree.params.nonEmpty())
log.error(tree.params.head.pos(),
"intf.annotation.members.cant.have.params");
// Attribute all value parameters.
for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
attribStat(l.head, localEnv);
}
// Check that type parameters are well-formed.
chk.validateTypeParams(tree.typarams);
if ((owner.flags() & ANNOTATION) != 0 &&
tree.typarams.nonEmpty())
log.error(tree.typarams.head.pos(),
"intf.annotation.members.cant.have.type.params");
// Check that result type is well-formed.
chk.validate(tree.restype);
if ((owner.flags() & ANNOTATION) != 0)
chk.validateAnnotationType(tree.restype);
if ((owner.flags() & ANNOTATION) != 0)
chk.validateAnnotationMethod(tree.pos(), m);
// Check that all exceptions mentioned in the throws clause extend
// java.lang.Throwable.
if ((owner.flags() & ANNOTATION) != 0 && tree.thrown.nonEmpty())
log.error(tree.thrown.head.pos(),
"throws.not.allowed.in.intf.annotation");
for (List<JCExpression> l = tree.thrown; l.nonEmpty(); l = l.tail)
chk.checkType(l.head.pos(), l.head.type, syms.throwableType);
if (tree.body == null) {
// Empty bodies are only allowed for
// abstract, native, or interface methods, or for methods
// in a retrofit signature class.
if ((owner.flags() & INTERFACE) == 0 &&
(tree.mods.flags & (ABSTRACT | NATIVE)) == 0 &&
!relax)
log.error(tree.pos(), "missing.meth.body.or.decl.abstract");
if (tree.defaultValue != null) {
if ((owner.flags() & ANNOTATION) == 0)
log.error(tree.pos(),
"default.allowed.in.intf.annotation.member");
}
} else if ((owner.flags() & INTERFACE) != 0) {
log.error(tree.body.pos(), "intf.meth.cant.have.body");
} else if ((tree.mods.flags & ABSTRACT) != 0) {
log.error(tree.pos(), "abstract.meth.cant.have.body");
} else if ((tree.mods.flags & NATIVE) != 0) {
log.error(tree.pos(), "native.meth.cant.have.body");
} else {
// Add an implicit super() call unless an explicit call to
// super(...) or this(...) is given
// or we are compiling class java.lang.Object.
if (tree.name == names.init && owner.type != syms.objectType) {
JCBlock body = tree.body;
if (body.stats.isEmpty() ||
!TreeInfo.isSelfCall(body.stats.head)) {
body.stats = body.stats.
prepend(memberEnter.SuperCall(make.at(body.pos),
List.<Type>nil(),
List.<JCVariableDecl>nil(),
false));
} else if ((env.enclClass.sym.flags() & ENUM) != 0 &&
(tree.mods.flags & GENERATEDCONSTR) == 0 &&
TreeInfo.isSuperCall(body.stats.head)) {
/*如:
enum EA {
;
EA() { super(); }
}
*/
// enum constructors are not allowed to call super
// directly, so make sure there aren't any super calls
// in enum constructors, except in the compiler
// generated one.
log.error(tree.body.stats.head.pos(),
"call.to.super.not.allowed.in.enum.ctor",
env.enclClass.sym);
}
}
// Attribute method body.
attribStat(tree.body, localEnv);
}
localEnv.info.scope.leave();
result = tree.type = m.type;
chk.validateAnnotations(tree.mods.annotations, m);
}
finally {
chk.setLint(prevLint);
DEBUG.P(1,this,"visitMethodDef(JCMethodDecl tree)");
}
}
public void visitVarDef(JCVariableDecl tree) {
DEBUG.P(this,"visitVarDef(1)");
DEBUG.P("tree="+tree);
DEBUG.P("env.info.scope前="+env.info.scope);
DEBUG.P("env.info.scope.owner="+env.info.scope.owner);
DEBUG.P("env.info.scope.owner.kind="+Kinds.toString(env.info.scope.owner.kind));
// Local variables have not been entered yet, so we need to do it now:
if (env.info.scope.owner.kind == MTH) {
DEBUG.P("tree.sym="+tree.sym);
/*方法的参数和方法体中的局部变量在两个作用域(Scope)中，如:
class Aclass<T> {
void m(int a) {
int b;
}
}
env.info.scope=Scope[(entries=1 nelems=1 owner=m())b | (entries=1 nelems=1 owner=m())a | (entries=3 nelems=3 owner=Aclass)super, this, T]
*/
if (tree.sym != null) { //方法参数已在MemberEnter.signature(5)中加入
// parameters have already been entered
env.info.scope.enter(tree.sym);
} else {
memberEnter.memberEnter(tree, env);
annotate.flush();
}
}
DEBUG.P("env.info.scope后="+env.info.scope);
DEBUG.P("chk.validate 前");
// Check that the variable's declared type is well-formed.
chk.validate(tree.vartype);
VarSymbol v = tree.sym;
Lint lint = env.info.lint.augment(v.attributes_field, v.flags());
Lint prevLint = chk.setLint(lint);
try {
chk.checkDeprecatedAnnotation(tree.pos(), v);
DEBUG.P("tree.init="+tree.init);
if (tree.init != null) {
if ((v.flags_field & FINAL) != 0 && tree.init.tag != JCTree.NEWCLASS) {
// In this case, `v' is final. Ensure that it's initializer is
// evaluated.
v.getConstValue(); // ensure initializer is evaluated
} else {
// Attribute initializer in a new environment
// with the declared variable as owner.
// Check that initializer conforms to variable's declared type.
Env<AttrContext> initEnv = memberEnter.initEnv(tree, env);
initEnv.info.lint = lint;
// In order to catch self-references, we set the variable's
// declaration position to maximal possible value, effectively
// marking the variable as undefined.
v.pos = Position.MAXPOS;
attribExpr(tree.init, initEnv, v.type);
v.pos = tree.pos;
}
}
result = tree.type = v.type;
chk.validateAnnotations(tree.mods.annotations, v);
}
finally {
chk.setLint(prevLint);
}
DEBUG.P(0,this,"visitVarDef(1)");
}
public void visitSkip(JCSkip tree) {
result = null;
}
public void visitBlock(JCBlock tree) {
DEBUG.P(this,"visitBlock(1)");
DEBUG.P("env.info.scope.owner="+env.info.scope.owner);
DEBUG.P("env.info.scope.owner.kind="+Kinds.toString(env.info.scope.owner.kind));
if (env.info.scope.owner.kind == TYP) { //实例、static初始块
// Block is a static or instance initializer;
// let the owner of the environment be a freshly
// created BLOCK-method.
Env<AttrContext> localEnv =
env.dup(tree, env.info.dup(env.info.scope.dupUnshared()));
localEnv.info.scope.owner =
new MethodSymbol(tree.flags | BLOCK, names.empty, null,
env.info.scope.owner);
if ((tree.flags & STATIC) != 0) localEnv.info.staticLevel++;
DEBUG.P("localEnv="+localEnv);
attribStats(tree.stats, localEnv);
} else {
// Create a new local environment with a local scope.
Env<AttrContext> localEnv =
env.dup(tree, env.info.dup(env.info.scope.dup()));
DEBUG.P("localEnv="+localEnv);
attribStats(tree.stats, localEnv);
localEnv.info.scope.leave();
}
result = null;
DEBUG.P(0,this,"visitBlock(1)");
}
//JCBlock、JCDoWhileLoop、JCWhileLoop、JCForLoop、JCEnhancedForLoop对应的type都为null
//因为它们都是语句，语句没有类型
public void visitDoLoop(JCDoWhileLoop tree) {
attribStat(tree.body, env.dup(tree));
attribExpr(tree.cond, env, syms.booleanType);
result = null;
}
public void visitWhileLoop(JCWhileLoop tree) {
attribExpr(tree.cond, env, syms.booleanType);
attribStat(tree.body, env.dup(tree));
result = null;
}
/*
class Aclass {
{
int i=10;
for(int i=10,j=20;;);
}
void m(int i) {
for(int i=10,j=20;;);
}
}
test\attr\AttrTests.java:8: 已在 中定义 i
for(int i=10,j=20;;);
^
test\attr\AttrTests.java:11: 已在 m(int) 中定义 i
for(int i=10,j=20;;);
^
2 错误
*/
public void visitForLoop(JCForLoop tree) {
DEBUG.P(this,"visitForLoop(1)");
Env<AttrContext> loopEnv =
env.dup(env.tree, env.info.dup(env.info.scope.dup()));
DEBUG.P("loopEnv="+loopEnv);
attribStats(tree.init, loopEnv);
if (tree.cond != null) attribExpr(tree.cond, loopEnv, syms.booleanType);
loopEnv.tree = tree; // before, we were not in loop!
attribStats(tree.step, loopEnv);
attribStat(tree.body, loopEnv);
loopEnv.info.scope.leave();
result = null;
DEBUG.P("tree.type = "+tree.type);
DEBUG.P(0,this,"visitForLoop(1)");
}
public void visitForeachLoop(JCEnhancedForLoop tree) {
DEBUG.P(this,"visitForeachLoop(1)");
Env<AttrContext> loopEnv =
env.dup(env.tree, env.info.dup(env.info.scope.dup()));
attribStat(tree.var, loopEnv);
Type exprType = types.upperBound(attribExpr(tree.expr, loopEnv));
chk.checkNonVoid(tree.pos(), exprType);
Type elemtype = types.elemtype(exprType); // perhaps expr is an array?
DEBUG.P("elemtype = "+elemtype);
//如果types.elemtype(exprType)返回值不为null，要么是ERROR，要么是数组元素类型
if (elemtype == null) {
// or perhaps expr implements Iterable<T>?
Type base = types.asSuper(exprType, syms.iterableType.tsym);
DEBUG.P("base = "+base);
if (base == null) {
log.error(tree.expr.pos(), "foreach.not.applicable.to.type");
elemtype = syms.errType;
} else {
List<Type> iterableParams = base.allparams();
DEBUG.P("iterableParams = "+iterableParams);
elemtype = iterableParams.isEmpty()
? syms.objectType
: types.upperBound(iterableParams.head);
}
}
DEBUG.P("elemtype = "+elemtype);
chk.checkType(tree.expr.pos(), elemtype, tree.var.sym.type);
loopEnv.tree = tree; // before, we were not in loop!
attribStat(tree.body, loopEnv);
loopEnv.info.scope.leave();
result = null;
DEBUG.P(0,this,"visitForeachLoop(1)");
}
public void visitLabelled(JCLabeledStatement tree) {
DEBUG.P(this,"visitLabelled(1)");
// Check that label is not used in an enclosing statement
Env<AttrContext> env1 = env;
while (env1 != null && env1.tree.tag != JCTree.CLASSDEF) {
//例:labelA:while(true) labelA: break;
//从内往外看，第二个labelA出错:标签 labelA 已使用
if (env1.tree.tag == JCTree.LABELLED &&
((JCLabeledStatement) env1.tree).label == tree.label) {
log.error(tree.pos(), "label.already.in.use",
tree.label);
break;
}
env1 = env1.next;
}
attribStat(tree.body, env.dup(tree));
result = null;
DEBUG.P(0,this,"visitLabelled(1)");
}
public void visitSwitch(JCSwitch tree) {
DEBUG.P(this,"visitSwitch(1)");
Type seltype = attribExpr(tree.selector, env);
Env<AttrContext> switchEnv =
env.dup(tree, env.info.dup(env.info.scope.dup()));
boolean enumSwitch =
allowEnums &&
(seltype.tsym.flags() & Flags.ENUM) != 0;
if (!enumSwitch)
seltype = chk.checkType(tree.selector.pos(), seltype, syms.intType);
// Attribute all cases and
// check that there are no duplicate case labels or default clauses.
Set<Object> labels = new HashSet<Object>(); // The set of case labels.
boolean hasDefault = false; // Is there a default label?
for (List<JCCase> l = tree.cases; l.nonEmpty(); l = l.tail) {
JCCase c = l.head;
Env<AttrContext> caseEnv =
switchEnv.dup(c, env.info.dup(switchEnv.info.scope.dup()));
if (c.pat != null) {
if (enumSwitch) {
Symbol sym = enumConstant(c.pat, seltype);
if (sym == null) {
log.error(c.pat.pos(), "enum.const.req");
} else if (!labels.add(sym)) {
log.error(c.pos(), "duplicate.case.label");
}
} else {
Type pattype = attribExpr(c.pat, switchEnv, seltype);
if (pattype.tag != ERROR) {
if (pattype.constValue() == null) {
log.error(c.pat.pos(), "const.expr.req");
} else if (labels.contains(pattype.constValue())) {
log.error(c.pos(), "duplicate.case.label");
} else {
labels.add(pattype.constValue());
}
}
}
} else if (hasDefault) {
log.error(c.pos(), "duplicate.default.label");
} else {
hasDefault = true;
}
attribStats(c.stats, caseEnv);
caseEnv.info.scope.leave();
addVars(c.stats, switchEnv.info.scope);
}
switchEnv.info.scope.leave();
result = null;
DEBUG.P(0,this,"visitSwitch(1)");
}
// where
/** Add any variables defined in stats to the switch scope. */
private static void addVars(List<JCStatement> stats, Scope switchScope) {
for (;stats.nonEmpty(); stats = stats.tail) {
JCTree stat = stats.head;
if (stat.tag == JCTree.VARDEF)
switchScope.enter(((JCVariableDecl) stat).sym);
}
}
// where
/** Return the selected enumeration constant symbol, or null. */
private Symbol enumConstant(JCTree tree, Type enumType) {
//switch语句的selector如果是枚举类型，
//那么对应的case中不能在枚举常量前加枚举类型名
if (tree.tag != JCTree.IDENT) {
log.error(tree.pos(), "enum.label.must.be.unqualified.enum");
return syms.errSymbol;
}
JCIdent ident = (JCIdent)tree;
Name name = ident.name;
for (Scope.Entry e = enumType.tsym.members().lookup(name);
e.scope != null; e = e.next()) {
if (e.sym.kind == VAR) {
Symbol s = ident.sym = e.sym;
((VarSymbol)s).getConstValue(); // ensure initializer is evaluated
ident.type = s.type;
return ((s.flags_field & Flags.ENUM) == 0)
? null : s;
}
}
return null;
}
public void visitSynchronized(JCSynchronized tree) {
DEBUG.P(this,"visitSynchronized(1)");
chk.checkRefType(tree.pos(), attribExpr(tree.lock, env));
attribStat(tree.body, env);
result = null;
DEBUG.P(0,this,"visitSynchronized(1)");
}
public void visitTry(JCTry tree) {
DEBUG.P(this,"visitTry(1)");
// Attribute body
attribStat(tree.body, env.dup(tree, env.info.dup()));
// Attribute catch clauses
for (List<JCCatch> l = tree.catchers; l.nonEmpty(); l = l.tail) {
JCCatch c = l.head;
Env<AttrContext> catchEnv =
env.dup(c, env.info.dup(env.info.scope.dup()));
Type ctype = attribStat(c.param, catchEnv);
if (c.param.type.tsym.kind == Kinds.VAR) {
c.param.sym.setData(ElementKind.EXCEPTION_PARAMETER);
}
chk.checkType(c.param.vartype.pos(),
chk.checkClassType(c.param.vartype.pos(), ctype),
syms.throwableType);
attribStat(c.body, catchEnv);
catchEnv.info.scope.leave();
}
// Attribute finalizer
//注意这里的env没有用JCTry tree
if (tree.finalizer != null) attribStat(tree.finalizer, env);
result = null;
DEBUG.P(0,this,"visitTry(1)");
}
public void visitConditional(JCConditional tree) {
DEBUG.P(this,"visitConditional(1)");
attribExpr(tree.cond, env, syms.booleanType);
attribExpr(tree.truepart, env);
attribExpr(tree.falsepart, env);
result = check(tree,
capture(condType(tree.pos(), tree.cond.type,
tree.truepart.type, tree.falsepart.type)),
VAL, pkind, pt);
DEBUG.P(0,this,"visitConditional(1)");
}
//where
/** Compute the type of a conditional expression, after
* checking that it exists. See Spec 15.25.
*
* @param pos The source position to be used for
* error diagnostics.
* @param condtype The type of the expression's condition.
* @param thentype The type of the expression's then-part.
* @param elsetype The type of the expression's else-part.
*/
private Type condType(DiagnosticPosition pos,
Type condtype,
Type thentype,
Type elsetype) {
try {//我加上的
DEBUG.P(this,"condType(4)");
Type ctype = condType1(pos, condtype, thentype, elsetype);
// If condition and both arms are numeric constants,
// evaluate at compile-time.
return ((condtype.constValue() != null) &&
(thentype.constValue() != null) &&
(elsetype.constValue() != null))
? cfolder.coerce(condtype.isTrue()?thentype:elsetype, ctype)
: ctype;
}finally{//我加上的
DEBUG.P(0,this,"condType(4)");
}
}
/** Compute the type of a conditional expression, after
* checking that it exists. Does not take into
* account the special case where condition and both arms
* are constants.
*
* @param pos The source position to be used for error
* diagnostics.
* @param condtype The type of the expression's condition.
* @param thentype The type of the expression's then-part.
* @param elsetype The type of the expression's else-part.
*/
private Type condType1(DiagnosticPosition pos, Type condtype,
Type thentype, Type elsetype) {
try {//我加上的
DEBUG.P(this,"condType1(4)");
DEBUG.P("condtype="+condtype);
DEBUG.P("thentype="+thentype);
DEBUG.P("elsetype="+elsetype);
// If same type, that is the result
if (types.isSameType(thentype, elsetype))
return thentype.baseType();
Type thenUnboxed = (!allowBoxing || thentype.isPrimitive())
? thentype : types.unboxedType(thentype);
Type elseUnboxed = (!allowBoxing || elsetype.isPrimitive())
? elsetype : types.unboxedType(elsetype);
DEBUG.P("thenUnboxed="+thenUnboxed);
DEBUG.P("elseUnboxed="+elseUnboxed);
// Otherwise, if both arms can be converted to a numeric
// type, return the least numeric type that fits both arms
// (i.e. return larger of the two, or return int if one
// arm is short, the other is char).
if (thenUnboxed.isPrimitive() && elseUnboxed.isPrimitive()) {
// If one arm has an integer subrange type (i.e., byte,
// short, or char), and the other is an integer constant
// that fits into the subrange, return the subrange type.
if (thenUnboxed.tag < INT && elseUnboxed.tag == INT &&
types.isAssignable(elseUnboxed, thenUnboxed))
return thenUnboxed.baseType();
if (elseUnboxed.tag < INT && thenUnboxed.tag == INT &&
types.isAssignable(thenUnboxed, elseUnboxed))
return elseUnboxed.baseType();
for (int i = BYTE; i < VOID; i++) {
Type candidate = syms.typeOfTag[i];
if (types.isSubtype(thenUnboxed, candidate) &&
types.isSubtype(elseUnboxed, candidate))
return candidate;
}
}
// Those were all the cases that could result in a primitive
if (allowBoxing) {
if (thentype.isPrimitive())
thentype = types.boxedClass(thentype).type;
if (elsetype.isPrimitive())
elsetype = types.boxedClass(elsetype).type;
}
if (types.isSubtype(thentype, elsetype))
return elsetype.baseType();
if (types.isSubtype(elsetype, thentype))
return thentype.baseType();
if (!allowBoxing || thentype.tag == VOID || elsetype.tag == VOID) {
log.error(pos, "neither.conditional.subtype",
thentype, elsetype);
return thentype.baseType();
}
// both are known to be reference types. The result is
// lub(thentype,elsetype). This cannot fail, as it will
// always be possible to infer "Object" if nothing better.
return types.lub(thentype.baseType(), elsetype.baseType());
}finally{//我加上的
DEBUG.P(0,this,"condType1(2)");
}
}
public void visitIf(JCIf tree) {
DEBUG.P(this,"visitIf(1)");
attribExpr(tree.cond, env, syms.booleanType);
attribStat(tree.thenpart, env);
if (tree.elsepart != null)
attribStat(tree.elsepart, env);
chk.checkEmptyIf(tree);
result = null;
DEBUG.P(0,this,"visitIf(1)");
}
public void visitExec(JCExpressionStatement tree) {
DEBUG.P(this,"visitExec(1)");
attribExpr(tree.expr, env);
result = null;
DEBUG.P(0,this,"visitExec(1)");
}
public void visitBreak(JCBreak tree) {
tree.target = findJumpTarget(tree.pos(), tree.tag, tree.label, env);
result = null;
}
public void visitContinue(JCContinue tree) {
tree.target = findJumpTarget(tree.pos(), tree.tag, tree.label, env);
result = null;
}
//where
/** Return the target of a break or continue statement, if it exists,
* report an error if not.
* Note: The target of a labelled break or continue is the
* (non-labelled) statement tree referred to by the label,
* not the tree representing the labelled statement itself.
*
* @param pos The position to be used for error diagnostics
* @param tag The tag of the jump statement. This is either
* Tree.BREAK or Tree.CONTINUE.
* @param label The label of the jump statement, or null if no
* label is given.
* @param env The environment current at the jump statement.
*/
private JCTree findJumpTarget(DiagnosticPosition pos,
int tag,
Name label,
Env<AttrContext> env) {
// Search environments outwards from the point of jump.
Env<AttrContext> env1 = env;
LOOP:
while (env1 != null) {
switch (env1.tree.tag) {
case JCTree.LABELLED:
JCLabeledStatement labelled = (JCLabeledStatement)env1.tree;
if (label == labelled.label) {
// If jump is a continue, check that target is a loop.
if (tag == JCTree.CONTINUE) {
if (labelled.body.tag != JCTree.DOLOOP &&
labelled.body.tag != JCTree.WHILELOOP &&
labelled.body.tag != JCTree.FORLOOP &&
labelled.body.tag != JCTree.FOREACHLOOP)
log.error(pos, "not.loop.label", label);
// Found labelled statement target, now go inwards
// to next non-labelled tree.
return TreeInfo.referencedStatement(labelled);
} else {
return labelled;
}
}
break;
case JCTree.DOLOOP:
case JCTree.WHILELOOP:
case JCTree.FORLOOP:
case JCTree.FOREACHLOOP:
if (label == null) return env1.tree;
break;
case JCTree.SWITCH:
if (label == null && tag == JCTree.BREAK) return env1.tree;
break;
case JCTree.METHODDEF:
case JCTree.CLASSDEF:
break LOOP;
default:
}
env1 = env1.next;
}
if (label != null)
log.error(pos, "undef.label", label);
else if (tag == JCTree.CONTINUE)
log.error(pos, "cont.outside.loop");
else
log.error(pos, "break.outside.switch.loop");
return null;
}
public void visitReturn(JCReturn tree) {
DEBUG.P(this,"visitReturn(1)");
// Check that there is an enclosing method which is
// nested within than the enclosing class.
//env.enclMethod=null，如:实例化块{ return; }
if(env.enclMethod!=null) {
DEBUG.P("env.enclMethod.sym.owner="+env.enclMethod.sym.owner);
DEBUG.P("env.enclClass.sym="+env.enclClass.sym);
} else DEBUG.P("env.enclMethod="+null);
if (env.enclMethod == null ||
env.enclMethod.sym.owner != env.enclClass.sym) { //???什么时候满足这个条件
log.error(tree.pos(), "ret.outside.meth");
} else {
// Attribute return expression, if it exists, and check that
// it conforms to result type of enclosing method.
Symbol m = env.enclMethod.sym;
if (m.type.getReturnType().tag == VOID) {
if (tree.expr != null)
log.error(tree.expr.pos(),
"cant.ret.val.from.meth.decl.void");
} else if (tree.expr == null) {
log.error(tree.pos(), "missing.ret.val");
} else {
attribExpr(tree.expr, env, m.type.getReturnType());
}
}
result = null;
DEBUG.P(0,this,"visitReturn(1)");
}
public void visitThrow(JCThrow tree) {
attribExpr(tree.expr, env, syms.throwableType);
result = null;
}
public void visitAssert(JCAssert tree) {
DEBUG.P(this,"visitAssert(1)");
attribExpr(tree.cond, env, syms.booleanType);
if (tree.detail != null) {
chk.checkNonVoid(tree.detail.pos(), attribExpr(tree.detail, env));
}
result = null;
DEBUG.P(0,this,"visitAssert(1)");
}
/** Visitor method for method invocations.
* NOTE: The method part of an application will have in its type field
* the return type of the method, not the method's type itself!
*/
public void visitApply(JCMethodInvocation tree) {
DEBUG.P(this,"visitApply(1)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.meth="+tree.meth);
DEBUG.P("tree.typeargs="+tree.typeargs);
DEBUG.P("tree.args="+tree.args);
DEBUG.P("tree.varargsElement="+tree.varargsElement);
// The local environment of a method application is
// a new environment nested in the current one.
Env<AttrContext> localEnv = env.dup(tree, env.info.dup());
DEBUG.P("localEnv="+localEnv);
// The types of the actual method arguments.
List<Type> argtypes;
// The types of the actual method type arguments.
List<Type> typeargtypes = null;
Name methName = TreeInfo.name(tree.meth);
DEBUG.P("methName="+methName);
boolean isConstructorCall =
methName == names._this || methName == names._super;
DEBUG.P("isConstructorCall="+isConstructorCall);
if (isConstructorCall) {
// We are seeing a ...this(...) or ...super(...) call.
// Check that this is the first statement in a constructor.
if (checkFirstConstructorStat(tree, env)) {
//注意:是传入env，而不是localEnv
// Record the fact
// that this is a constructor call (using isSelfCall).
localEnv.info.isSelfCall = true;
// Attribute arguments, yielding list of argument types.
DEBUG.P("tree.args="+tree.args);
DEBUG.P("tree.typeargs="+tree.typeargs);
argtypes = attribArgs(tree.args, localEnv);
typeargtypes = attribTypes(tree.typeargs, localEnv);
// Variable `site' points to the class in which the called
// constructor is defined.
Type site = env.enclClass.sym.type;
DEBUG.P("site="+site);
DEBUG.P("methName="+methName);
if (methName == names._super) {
if (site == syms.objectType) {
log.error(tree.meth.pos(), "no.superclass", site);
site = syms.errType;
} else {
site = types.supertype(site);
}
}
DEBUG.P("site="+site);
DEBUG.P("site.tag="+TypeTags.toString(site.tag));
if (site.tag == CLASS) {
DEBUG.P("site.getEnclosingType().tag="+TypeTags.toString(site.getEnclosingType().tag));
if (site.getEnclosingType().tag == CLASS) {
// we are calling a nested class
if (tree.meth.tag == JCTree.SELECT) {
JCTree qualifier = ((JCFieldAccess) tree.meth).selected;
// We are seeing a prefixed call, of the form
// <expr>.super(...).
// Check that the prefix expression conforms
// to the outer instance type of the class.
chk.checkRefType(qualifier.pos(),
attribExpr(qualifier, localEnv,
site.getEnclosingType()));
} else if (methName == names._super) {
// qualifier omitted; check for existence
// of an appropriate implicit qualifier.
rs.resolveImplicitThis(tree.meth.pos(),
localEnv, site);
}
} else if (tree.meth.tag == JCTree.SELECT) {
//例:class ClassA { ClassA() { ClassA.super(); } }
log.error(tree.meth.pos(), "illegal.qual.not.icls",
site.tsym);
}
// if we're calling a java.lang.Enum constructor,
// prefix the implicit String and int parameters
if (site.tsym == syms.enumSym && allowEnums)
argtypes = argtypes.prepend(syms.intType).prepend(syms.stringType);
// Resolve the called constructor under the assumption
// that we are referring to a superclass instance of the
// current instance (JLS ???).
boolean selectSuperPrev = localEnv.info.selectSuper;
localEnv.info.selectSuper = true;
localEnv.info.varArgs = false;
Symbol sym = rs.resolveConstructor(
tree.meth.pos(), localEnv, site, argtypes, typeargtypes);
localEnv.info.selectSuper = selectSuperPrev;
// Set method symbol to resolved constructor...
TreeInfo.setSymbol(tree.meth, sym);
// ...and check that it is legal in the current context.
// (this will also set the tree's type)
Type mpt = newMethTemplate(argtypes, typeargtypes);
checkId(tree.meth, site, sym, localEnv, MTH,
mpt, tree.varargsElement != null);
}
// Otherwise, `site' is an error type and we do nothing
}
result = tree.type = syms.voidType;
} else {
// Otherwise, we are seeing a regular method call.
// Attribute the arguments, yielding list of argument types, ...
argtypes = attribArgs(tree.args, localEnv);
typeargtypes = attribTypes(tree.typeargs, localEnv);
// ... and attribute the method using as a prototype a methodtype
// whose formal argument types is exactly the list of actual
// arguments (this will also set the method symbol).
Type mpt = newMethTemplate(argtypes, typeargtypes);
localEnv.info.varArgs = false;
Type mtype = attribExpr(tree.meth, localEnv, mpt);
if (localEnv.info.varArgs)
assert mtype.isErroneous() || tree.varargsElement != null;
// Compute the result type.
Type restype = mtype.getReturnType();
assert restype.tag != WILDCARD : mtype;
// as a special case, array.clone() has a result that is
// the same as static type of the array being cloned
if (tree.meth.tag == JCTree.SELECT &&
allowCovariantReturns &&
methName == names.clone &&
types.isArray(((JCFieldAccess) tree.meth).selected.type))
restype = ((JCFieldAccess) tree.meth).selected.type;
// as a special case, x.getClass() has type Class<? extends |X|>
if (allowGenerics &&
methName == names.getClass && tree.args.isEmpty()) {
Type qualifier = (tree.meth.tag == JCTree.SELECT)
? ((JCFieldAccess) tree.meth).selected.type
: env.enclClass.sym.type;
restype = new
ClassType(restype.getEnclosingType(),
List.<Type>of(new WildcardType(types.erasure(qualifier),
BoundKind.EXTENDS,
syms.boundClass)),
restype.tsym);
}
// Check that value of resulting type is admissible in the
// current context. Also, capture the return type
result = check(tree, capture(restype), VAL, pkind, pt);
}
chk.validate(tree.typeargs);
DEBUG.P(0,this,"visitApply(1)");
}
//where
/** Check that given application node appears as first statement
* in a constructor call.
* @param tree The application node
* @param env The environment current at the application.
*/
//调用这个方法的前提是存在this(...)或super(...)调用，
//因为可能在方法或构造函数中任何位置调用this(...)或super(...)，
//所以必须检查只有在构造函数中第一条语句才能调用this(...)或super(...)
//下面的enclMethod表示调用this(...)或super(...)的方法或构造函数
//JCMethodInvocation tree表示this(...)或super(...)
boolean checkFirstConstructorStat(JCMethodInvocation tree, Env<AttrContext> env) {
try {//我加上的
DEBUG.P(this,"checkFirstConstructorStat(2)");
DEBUG.P("tree="+tree);
DEBUG.P("env="+env);
JCMethodDecl enclMethod = env.enclMethod;
if(enclMethod != null) DEBUG.P("enclMethod.name="+enclMethod.name);
else DEBUG.P("enclMethod=null");
//如果在实例初始化语句块或静态语句块(如{this();} static {this();})
//此时enclMethod为null，所以下面加了enclMethod != null条件
if (enclMethod != null && enclMethod.name == names.init) {
JCBlock body = enclMethod.body;
//第一条语句是JCMethodInvocation tree(即:this(...)或super(...))
if (body.stats.head.tag == JCTree.EXEC &&
((JCExpressionStatement) body.stats.head).expr == tree)
return true;
}
log.error(tree.pos(),"call.must.be.first.stmt.in.ctor",
TreeInfo.name(tree.meth));
return false;
}finally{//我加上的
DEBUG.P(0,this,"checkFirstConstructorStat(2)");
}
}
/** Obtain a method type with given argument types.
*/
Type newMethTemplate(List<Type> argtypes, List<Type> typeargtypes) {
DEBUG.P(this,"newMethTemplate(2)");
DEBUG.P("argtypes="+argtypes);
DEBUG.P("typeargtypes="+typeargtypes);
MethodType mt = new MethodType(argtypes, null, null, syms.methodClass);
//typeargtypes不会为null,因为attribTypes(2)不会返回null
//return (typeargtypes == null) ? mt : (Type)new ForAll(typeargtypes, mt);
Type newMeth = (typeargtypes == null) ? mt : (Type)new ForAll(typeargtypes, mt);
DEBUG.P("newMeth="+newMeth);
DEBUG.P(0,this,"newMethTemplate(2)");
return newMeth;
}
public void visitNewClass(JCNewClass tree) {
DEBUG.P(this,"visitNewClass(1)");
DEBUG.P("tree="+tree);
Type owntype = syms.errType;
// The local environment of a class creation is
// a new environment nested in the current one.
Env<AttrContext> localEnv = env.dup(tree, env.info.dup());
DEBUG.P("localEnv="+localEnv);
// The anonymous inner class definition of the new expression,
// if one is defined by it.
JCClassDecl cdef = tree.def;
// If enclosing class is given, attribute it, and
// complete class name to be fully qualified
JCExpression clazz = tree.clazz; // Class field following new
DEBUG.P("clazz="+clazz);
DEBUG.P("clazz.tag="+clazz.myTreeTag());
JCExpression clazzid = // Identifier in class field
(clazz.tag == JCTree.TYPEAPPLY)
? ((JCTypeApply) clazz).clazz
: clazz;
JCExpression clazzid1 = clazzid; // The same in fully qualified form
DEBUG.P("clazzid="+clazzid);
DEBUG.P("tree.encl="+tree.encl);
//如果(tree.encl != null)，那么就不能用 “<expr>.new 完全限定类名”这样的语法
//如ClassA.new test.ClassB();这样的语法是错误的
if (tree.encl != null) {
// We are seeing a qualified new, of the form
// <expr>.new C <...> (...) ...
// In this case, we let clazz stand for the name of the
// allocated class C prefixed with the type of the qualifier
// expression, so that we can
// resolve it with standard techniques later. I.e., if
// <expr> has type T, then <expr>.new C <...> (...)
// yields a clazz T.C.
Type encltype = chk.checkRefType(tree.encl.pos(),
attribExpr(tree.encl, env));
clazzid1 = make.at(clazz.pos).Select(make.Type(encltype),
((JCIdent) clazzid).name);
if (clazz.tag == JCTree.TYPEAPPLY)
clazz = make.at(tree.pos).
TypeApply(clazzid1,
((JCTypeApply) clazz).arguments);
else
clazz = clazzid1;
// System.out.println(clazz + " generated.");//DEBUG
}
// Attribute clazz expression and store
// symbol + type back into the attributed tree.
Type clazztype = chk.checkClassType(
tree.clazz.pos(), attribType(clazz, env), true);
chk.validate(clazz);
if (tree.encl != null) {
// We have to work in this case to store
// symbol + type back into the attributed tree.
tree.clazz.type = clazztype;
TreeInfo.setSymbol(clazzid, TreeInfo.symbol(clazzid1));
clazzid.type = ((JCIdent) clazzid).sym.type;
if (!clazztype.isErroneous()) {
if (cdef != null && clazztype.tsym.isInterface()) {
/* 如
class VisitSelectTest<T> {
interface InterfaceA {}
InterfaceA ia = new VisitSelectTest().new InterfaceA(){};
}
*/
log.error(tree.encl.pos(), "anon.class.impl.intf.no.qual.for.new");
} else if (clazztype.tsym.isStatic()) {
/* 如
class VisitSelectTest<T> {
static class ClassA {}
ClassA ca = new VisitSelectTest().new ClassA(){};
}
*/
log.error(tree.encl.pos(), "qualified.new.of.static.class", clazztype.tsym);
}
}
} else if (!clazztype.tsym.isInterface() &&
clazztype.getEnclosingType().tag == CLASS) {
// Check for the existence of an apropos outer instance
rs.resolveImplicitThis(tree.pos(), env, clazztype);
}
// Attribute constructor arguments.
List<Type> argtypes = attribArgs(tree.args, localEnv);
List<Type> typeargtypes = attribTypes(tree.typeargs, localEnv);
// If we have made no mistakes in the class type...
if (clazztype.tag == CLASS) {
// Enums may not be instantiated except implicitly
if (allowEnums &&
(clazztype.tsym.flags_field&Flags.ENUM) != 0 &&
(env.tree.tag != JCTree.VARDEF ||
(((JCVariableDecl) env.tree).mods.flags&Flags.ENUM) == 0 ||
((JCVariableDecl) env.tree).init != tree)) {
log.error(tree.pos(), "enum.cant.be.instantiated");
/*如:((JCVariableDecl) env.tree).init != tree)??????不知举什么例子)
enum EnumA {}
int ea = new EnumA();
EnumA eb = new EnumA();
class ClassA {
void m1(EnumA e) {}
void m2() {
m1(new EnumA());
}
}
*/
if(env.tree.tag == JCTree.VARDEF) {
DEBUG.P("((JCVariableDecl) env.tree).init="+((JCVariableDecl) env.tree).init);
DEBUG.P("tree="+tree);
DEBUG.P("(((JCVariableDecl) env.tree).init != tree)="+(((JCVariableDecl) env.tree).init != tree));
}
}
// Check that class is not abstract
//如:
//abstract class ClassA {}
//ClassA ca = new ClassA();
if (cdef == null &&
(clazztype.tsym.flags() & (ABSTRACT | INTERFACE)) != 0) {
log.error(tree.pos(), "abstract.cant.be.instantiated",
clazztype.tsym);
} else if (cdef != null && clazztype.tsym.isInterface()) {
// Check that no constructor arguments are given to
// anonymous classes implementing an interface
//如:
//interface InterfaceB {}
//InterfaceB ib = new InterfaceB(10,20){};
if (!argtypes.isEmpty())
log.error(tree.args.head.pos(), "anon.class.impl.intf.no.args");
//如:
//interface InterfaceB<T> {}
//InterfaceB<String> ib = new <String>InterfaceB(){};
if (!typeargtypes.isEmpty())
log.error(tree.typeargs.head.pos(), "anon.class.impl.intf.no.typeargs");
// Error recovery: pretend no arguments were supplied.
argtypes = List.nil();
typeargtypes = List.nil();
}
// Resolve the called constructor under the assumption
// that we are referring to a superclass instance of the
// current instance (JLS ???).
else {
localEnv.info.selectSuper = cdef != null;
localEnv.info.varArgs = false;
tree.constructor = rs.resolveConstructor(
tree.pos(), localEnv, clazztype, argtypes, typeargtypes);
Type ctorType = checkMethod(clazztype,
tree.constructor,
localEnv,
tree.args,
argtypes,
typeargtypes,
localEnv.info.varArgs);
if (localEnv.info.varArgs)
assert ctorType.isErroneous() || tree.varargsElement != null;
}
if (cdef != null) {
// We are seeing an anonymous class instance creation.
// In this case, the class instance creation
// expression
//
// E.new <typeargs1>C<typargs2>(args) { ... }
//
// is represented internally as
//
// E . new <typeargs1>C<typargs2>(args) ( class <empty-name> { ... } ) .
//
// This expression is then *transformed* as follows:
//
// (1) add a STATIC flag to the class definition
// if the current environment is static
// (2) add an extends or implements clause
// (3) add a constructor.
//
// For instance, if C is a class, and ET is the type of E,
// the expression
//
// E.new <typeargs1>C<typargs2>(args) { ... }
//
// is translated to (where X is a fresh name and typarams is the
// parameter list of the super constructor):
//
// new <typeargs1>X(<*nullchk*>E, args) where
// X extends C<typargs2> {
// <typarams> X(ET e, args) {
// e.<typeargs1>super(args)
// }
// ...
// }
if (Resolve.isStatic(env)) cdef.mods.flags |= STATIC;
if (clazztype.tsym.isInterface()) {
cdef.implementing = List.of(clazz);
} else {
cdef.extending = clazz;
}
attribStat(cdef, localEnv);
// If an outer instance is given,
// prefix it to the constructor arguments
// and delete it from the new expression
if (tree.encl != null && !clazztype.tsym.isInterface()) {
tree.args = tree.args.prepend(makeNullCheck(tree.encl));
argtypes = argtypes.prepend(tree.encl.type);
tree.encl = null;
}
// Reassign clazztype and recompute constructor.
clazztype = cdef.sym.type;
Symbol sym = rs.resolveConstructor(
tree.pos(), localEnv, clazztype, argtypes,
typeargtypes, true, tree.varargsElement != null);
assert sym.kind < AMBIGUOUS || tree.constructor.type.isErroneous();
tree.constructor = sym;
}
if (tree.constructor != null && tree.constructor.kind == MTH)
owntype = clazztype;
}
result = check(tree, owntype, VAL, pkind, pt);
chk.validate(tree.typeargs);
DEBUG.P(1,this,"visitNewClass(1)");
}
/** Make an attributed null check tree.
*/
public JCExpression makeNullCheck(JCExpression arg) {
// optimization: X.this is never null; skip null check
Name name = TreeInfo.name(arg);
if (name == names._this || name == names._super) return arg;
int optag = JCTree.NULLCHK;
JCUnary tree = make.at(arg.pos).Unary(optag, arg);
tree.operator = syms.nullcheck;
tree.type = arg.type;
return tree;
}
public void visitNewArray(JCNewArray tree) {
Type owntype = syms.errType;
Type elemtype;
if (tree.elemtype != null) {
elemtype = attribType(tree.elemtype, env);
chk.validate(tree.elemtype);
owntype = elemtype;
for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
attribExpr(l.head, env, syms.intType);
owntype = new ArrayType(owntype, syms.arrayClass);
}
} else {
// we are seeing an untyped aggregate { ... }
// this is allowed only if the prototype is an array
if (pt.tag == ARRAY) {
elemtype = types.elemtype(pt);
} else {
if (pt.tag != ERROR) {
log.error(tree.pos(), "illegal.initializer.for.type",
pt);
}
elemtype = syms.errType;
}
}
if (tree.elems != null) {
attribExprs(tree.elems, env, elemtype);
owntype = new ArrayType(elemtype, syms.arrayClass);
}
if (!types.isReifiable(elemtype))
log.error(tree.pos(), "generic.array.creation");
result = check(tree, owntype, VAL, pkind, pt);
}
public void visitParens(JCParens tree) {
Type owntype = attribTree(tree.expr, env, pkind, pt);
result = check(tree, owntype, pkind, pkind, pt);
Symbol sym = TreeInfo.symbol(tree);
if (sym != null && (sym.kind&(TYP|PCK)) != 0)
log.error(tree.pos(), "illegal.start.of.type");
}
public void visitAssign(JCAssign tree) {
Type owntype = attribTree(tree.lhs, env.dup(tree), VAR, Type.noType);
Type capturedType = capture(owntype);
attribExpr(tree.rhs, env, owntype);
result = check(tree, capturedType, VAL, pkind, pt);
}
public void visitAssignop(JCAssignOp tree) {
// Attribute arguments.
Type owntype = attribTree(tree.lhs, env, VAR, Type.noType);
Type operand = attribExpr(tree.rhs, env);
// Find operator.
Symbol operator = tree.operator = rs.resolveBinaryOperator(
tree.pos(), tree.tag - JCTree.ASGOffset, env,
owntype, operand);
if (operator.kind == MTH) {
chk.checkOperator(tree.pos(),
(OperatorSymbol)operator,
tree.tag - JCTree.ASGOffset,
owntype,
operand);
if (types.isSameType(operator.type.getReturnType(), syms.stringType)) {
// String assignment; make sure the lhs is a string
chk.checkType(tree.lhs.pos(),
owntype,
syms.stringType);
} else {
chk.checkDivZero(tree.rhs.pos(), operator, operand);
chk.checkCastable(tree.rhs.pos(),
operator.type.getReturnType(),
owntype);
}
}
result = check(tree, owntype, VAL, pkind, pt);
}
public void visitUnary(JCUnary tree) {
// Attribute arguments.
Type argtype = (JCTree.PREINC <= tree.tag && tree.tag <= JCTree.POSTDEC)
? attribTree(tree.arg, env, VAR, Type.noType)
: chk.checkNonVoid(tree.arg.pos(), attribExpr(tree.arg, env));
// Find operator.
Symbol operator = tree.operator =
rs.resolveUnaryOperator(tree.pos(), tree.tag, env, argtype);
Type owntype = syms.errType;
if (operator.kind == MTH) {
owntype = (JCTree.PREINC <= tree.tag && tree.tag <= JCTree.POSTDEC)
? tree.arg.type
: operator.type.getReturnType();
int opc = ((OperatorSymbol)operator).opcode;
// If the argument is constant, fold it.
if (argtype.constValue() != null) {
Type ctype = cfolder.fold1(opc, argtype);
if (ctype != null) {
owntype = cfolder.coerce(ctype, owntype);
// Remove constant types from arguments to
// conserve space. The parser will fold concatenations
// of string literals; the code here also
// gets rid of intermediate results when some of the
// operands are constant identifiers.
if (tree.arg.type.tsym == syms.stringType.tsym) {
tree.arg.type = syms.stringType;
}
}
}
}
result = check(tree, owntype, VAL, pkind, pt);
}
public void visitBinary(JCBinary tree) {
DEBUG.P(this,"visitBinary(1)");
// Attribute arguments.
Type left = chk.checkNonVoid(tree.lhs.pos(), attribExpr(tree.lhs, env));
Type right = chk.checkNonVoid(tree.lhs.pos(), attribExpr(tree.rhs, env));
// Find operator.
Symbol operator = tree.operator =
rs.resolveBinaryOperator(tree.pos(), tree.tag, env, left, right);
Type owntype = syms.errType;
if (operator.kind == MTH) {
owntype = operator.type.getReturnType();
int opc = chk.checkOperator(tree.lhs.pos(),
(OperatorSymbol)operator,
tree.tag,
left,
right);
// If both arguments are constants, fold them.
if (left.constValue() != null && right.constValue() != null) {
Type ctype = cfolder.fold2(opc, left, right);
if (ctype != null) {
owntype = cfolder.coerce(ctype, owntype);
// Remove constant types from arguments to
// conserve space. The parser will fold concatenations
// of string literals; the code here also
// gets rid of intermediate results when some of the
// operands are constant identifiers.
if (tree.lhs.type.tsym == syms.stringType.tsym) {
tree.lhs.type = syms.stringType;
}
if (tree.rhs.type.tsym == syms.stringType.tsym) {
tree.rhs.type = syms.stringType;
}
}
}
// Check that argument types of a reference ==, != are
// castable to each other, (JLS???).
if ((opc == ByteCodes.if_acmpeq || opc == ByteCodes.if_acmpne)) {
if (!types.isCastable(left, right, new Warner(tree.pos()))) {
log.error(tree.pos(), "incomparable.types", left, right);
}
}
chk.checkDivZero(tree.rhs.pos(), operator, right);
}
result = check(tree, owntype, VAL, pkind, pt);
DEBUG.P(0,this,"visitBinary(1)");
}
public void visitTypeCast(JCTypeCast tree) {
Type clazztype = attribType(tree.clazz, env);
Type exprtype = attribExpr(tree.expr, env, Infer.anyPoly);
Type owntype = chk.checkCastable(tree.expr.pos(), exprtype, clazztype);
if (exprtype.constValue() != null)
owntype = cfolder.coerce(exprtype, owntype);
result = check(tree, capture(owntype), VAL, pkind, pt);
}
public void visitTypeTest(JCInstanceOf tree) {
Type exprtype = chk.checkNullOrRefType(
tree.expr.pos(), attribExpr(tree.expr, env));
Type clazztype = chk.checkReifiableReferenceType(
tree.clazz.pos(), attribType(tree.clazz, env));
chk.checkCastable(tree.expr.pos(), exprtype, clazztype);
result = check(tree, syms.booleanType, VAL, pkind, pt);
}
public void visitIndexed(JCArrayAccess tree) {
Type owntype = syms.errType;
Type atype = attribExpr(tree.indexed, env);
attribExpr(tree.index, env, syms.intType);
if (types.isArray(atype))
owntype = types.elemtype(atype);
else if (atype.tag != ERROR)
log.error(tree.pos(), "array.req.but.found", atype);
if ((pkind & VAR) == 0) owntype = capture(owntype);
result = check(tree, owntype, VAR, pkind, pt);
}
//在Attr阶段前JCIdent.sym是null的，在调用visitIdent()就有适当的值了
public void visitIdent(JCIdent tree) {
DEBUG.P(this,"visitIdent(1)");
Symbol sym;
boolean varArgs = false;
DEBUG.P("pt.tag="+TypeTags.toString(pt.tag));
DEBUG.P("tree.sym="+tree.sym);
if (tree.sym != null)
DEBUG.P("tree.sym.kind="+Kinds.toString(tree.sym.kind));
// Find symbol
if (pt.tag == METHOD || pt.tag == FORALL) {
// If we are looking for a method, the prototype `pt' will be a
// method type with the type of the call's arguments as parameters.
env.info.varArgs = false;
sym = rs.resolveMethod(tree.pos(), env, tree.name, pt.getParameterTypes(), pt.getTypeArguments());
varArgs = env.info.varArgs;
} else if (tree.sym != null && tree.sym.kind != VAR) {
sym = tree.sym;
} else {
sym = rs.resolveIdent(tree.pos(), env, tree.name, pkind);
}
tree.sym = sym;
DEBUG.P("tree.sym="+tree.sym);
DEBUG.P("tree.sym.kind="+Kinds.toString(tree.sym.kind));
// (1) Also find the environment current for the class where
// sym is defined (`symEnv').
// Only for pre-tiger versions (1.4 and earlier):
// (2) Also determine whether we access symbol out of an anonymous
// class in a this or super call. This is illegal for instance
// members since such classes don't carry a this$n link.
// (`noOuterThisPath').
Env<AttrContext> symEnv = env;
DEBUG.P("symEnv="+symEnv);
DEBUG.P("env.enclClass.sym.owner.kind="+Kinds.toString(env.enclClass.sym.owner.kind));
DEBUG.P("sym="+sym);
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));
DEBUG.P(1);
boolean noOuterThisPath = false;
if (env.enclClass.sym.owner.kind != PCK && // we are in an inner class
(sym.kind & (VAR | MTH | TYP)) != 0 &&
sym.owner.kind == TYP &&
tree.name != names._this && tree.name != names._super) {
if(symEnv.outer != null) {
DEBUG.P("sym="+sym);
DEBUG.P("symEnv.enclClass.sym="+symEnv.enclClass.sym);
DEBUG.P("symEnv.enclClass.sym.flags()="+Flags.toString(symEnv.enclClass.sym.flags()));
DEBUG.P("sym.isMemberOf(symEnv.enclClass.sym)="+sym.isMemberOf(symEnv.enclClass.sym, types));
}
// Find environment in which identifier is defined.
while (symEnv.outer != null &&
!sym.isMemberOf(symEnv.enclClass.sym, types)) {
if ((symEnv.enclClass.sym.flags() & NOOUTERTHIS) != 0)
noOuterThisPath = !allowAnonOuterThis;
symEnv = symEnv.outer;
}
}
DEBUG.P(1);
DEBUG.P("symEnv="+symEnv);
// If symbol is a variable, ...
if (sym.kind == VAR) {
VarSymbol v = (VarSymbol)sym;
// ..., evaluate its initializer, if it has one, and check for
// illegal forward reference.
checkInit(tree, env, v, false);
// If symbol is a local variable accessed from an embedded
// inner class check that it is final.
DEBUG.P("v="+v);
DEBUG.P("v.owner="+v.owner);
DEBUG.P("env.info.scope.owner="+env.info.scope.owner);
//在方法中定义的本地类或匿名本地类内部引用到方法的变量，变量必须是FINAL
if (v.owner.kind == MTH &&
v.owner != env.info.scope.owner &&
(v.flags_field & FINAL) == 0) {
log.error(tree.pos(),
"local.var.accessed.from.icls.needs.final",
v);
}
// If we are expecting a variable (as opposed to a value), check
// that the variable is assignable in the current environment.
DEBUG.P("pkind="+Kinds.toString(pkind));
DEBUG.P("if (pkind == VAR)="+(pkind == VAR));
if (pkind == VAR)
checkAssignable(tree.pos(), v, null, env);
}
DEBUG.P("symEnv.info.isSelfCall="+symEnv.info.isSelfCall);
DEBUG.P("noOuterThisPath="+noOuterThisPath);
// In a constructor body,
// if symbol is a field or instance method, check that it is
// not accessed before the supertype constructor is called.
if ((symEnv.info.isSelfCall || noOuterThisPath) &&
(sym.kind & (VAR | MTH)) != 0 &&
sym.owner.kind == TYP &&
(sym.flags() & STATIC) == 0) {
DEBUG.P("sym="+sym);
DEBUG.P("sym.kind="+Kinds.toString(sym.kind));
chk.earlyRefError(tree.pos(), sym.kind == VAR ? sym : thisSym(tree.pos(), env));
}
Env<AttrContext> env1 = env;
DEBUG.P("env1="+env1);
DEBUG.P("sym.owner="+sym.owner);
DEBUG.P("env1.enclClass.sym="+env1.enclClass.sym);
if (sym.kind != ERR && sym.owner != null && sym.owner != env1.enclClass.sym) {
// If the found symbol is inaccessible, then it is
// accessed through an enclosing instance. Locate this
// enclosing instance:
DEBUG.P("env1.outer="+env1.outer);
while (env1.outer != null && !rs.isAccessible(env, env1.enclClass.sym.type, sym))
env1 = env1.outer;
}
DEBUG.P("env1="+env1);
DEBUG.P("env1.enclClass.sym="+env1.enclClass.sym);
result = checkId(tree, env1.enclClass.sym.type, sym, env, pkind, pt, varArgs);
DEBUG.P(0,this,"visitIdent(1)");
}
public void visitSelect(JCFieldAccess tree) {
/*************************************************************
pkind表示当前期待tree.type.tsym是pkind指定的类型
例如pkind=PCK，就表示tree.type.tsym代表的是一个包(如:my.test)
**************************************************************/
// <editor-fold defaultstate="collapsed">
try {
DEBUG.P(this,"visitSelect(1)");
DEBUG.P("tree.name="+tree.name);
DEBUG.P("tree="+tree);
/*对于像Qualident = Ident { DOT Ident }这样的语法，
如果最后一个Ident是“this”、“super”、“class”，那么前
一个Ident的符号类型(symbol kind)只能是TYP，也就是说只有
类型名后面才能跟“this”、“super”、“class”；
如果最后一个Ident符号类型是PCK，那么前一个Ident的符号类型
也是PCK，因为包名前面只能是包名；
如果最后一个Ident符号类型是TYP，那么前一个Ident的符号类型
可以是TYP或PCK，因为类型名可以是内部类，这时前一个Ident
的符号类型就是TYP，否则只能是PCK；
如果最后一个Ident符号类型是VAL或MTH，也就是当它是
变量或非变量表达式(variables or non-variable expressions)
或者是方法名的时候，那么前一个Ident的符号类型
可以是VAL或TYP。
*/
// Determine the expected kind of the qualifier expression.
int skind = 0;
if (tree.name == names._this || tree.name == names._super ||
tree.name == names._class)
{
skind = TYP;
} else {
if ((pkind & PCK) != 0) skind = skind | PCK;
if ((pkind & TYP) != 0) skind = skind | TYP | PCK;
//注意:如果pkind=VAR，那么(pkind & (VAL | MTH)) != 0)是不等于0的
//因为(VAR & VAL)!=0;
//DEBUG.P("(VAR & VAL)="+(VAR & VAL));
if ((pkind & (VAL | MTH)) != 0) skind = skind | VAL | TYP;
}
// Attribute the qualifier expression, and determine its symbol (if any).
Type site = attribTree(tree.selected, env, skind, Infer.anyPoly);//Infer.anyPoly是一个Type(NONE, null)与JCNoType(NONE)类拟
DEBUG.P("site.tag="+TypeTags.toString(site.tag));
DEBUG.P("pkind="+Kinds.toString(pkind));
DEBUG.P("skind="+Kinds.toString(skind));
if ((pkind & (PCK | TYP)) == 0)
site = capture(site); // Capture field access
// don't allow T.class T[].class, etc
if (skind == TYP) {
Type elt = site;
while (elt.tag == ARRAY)
elt = ((ArrayType)elt).elemtype;
if (elt.tag == TYPEVAR) {
log.error(tree.pos(), "type.var.cant.be.deref");
result = syms.errType;
//我加上的，见if (tree.selected.type.tag == FORALL)的注释
tree.type = syms.errType;
return;
}
}
// </editor-fold>
// <editor-fold defaultstate="collapsed">
// If qualifier symbol is a type or `super', assert `selectSuper'
// for the selection. This is relevant for determining whether
// protected symbols are accessible.
DEBUG.P("tree.selected="+tree.selected);
Symbol sitesym = TreeInfo.symbol(tree.selected);
boolean selectSuperPrev = env.info.selectSuper;
DEBUG.P("sitesym="+sitesym);
if(sitesym==site.tsym)
DEBUG.P("sitesym==site.tsym");
else
DEBUG.P("sitesym!=site.tsym");
DEBUG.P("selectSuperPrev="+selectSuperPrev);
env.info.selectSuper =
sitesym != null &&
sitesym.name == names._super;
// If selected expression is polymorphic, strip
// type parameters and remember in env.info.tvars, so that
// they can be added later (in Attr.checkId and Infer.instantiateMethod).
DEBUG.P("env.info.selectSuper="+env.info.selectSuper);
try {
DEBUG.P("tree="+tree);
DEBUG.P("tree.selected="+tree.selected);
DEBUG.P("tree.selected.type="+tree.selected.type);
DEBUG.P("tree.selected.type.tag="+TypeTags.toString(tree.selected.type.tag));
/*
这里有NullPointerException
当编译T t=T.super.toString();时，
上面的skind = TYP，报告错误"无法从类型变量中进行选择"后返回，
但是没有对(T.super)JCFieldAccess tree.type赋值，
导致tree.selected.type = null;
*/
if (tree.selected.type.tag == FORALL) {
ForAll pstype = (ForAll)tree.selected.type;
env.info.tvars = pstype.tvars;
site = tree.selected.type = pstype.qtype;
}
} catch (RuntimeException e) {
System.err.println("出错了:"+e);
e.printStackTrace();
throw e;
}
// </editor-fold>
// <editor-fold defaultstate="collapsed">
// Determine the symbol represented by the selection.
env.info.varArgs = false;
Symbol sym = selectSym(tree, site, env, pt, pkind);
DEBUG.P("tree="+tree);
DEBUG.P("sym="+sym);
DEBUG.P("sym.type="+sym.type);
DEBUG.P("sym.kind="+Kinds.toString(sym.kind));
DEBUG.P("sym.exists()="+sym.exists());
DEBUG.P("isType(sym)="+isType(sym));
DEBUG.P("pkind="+Kinds.toString(pkind));
if (sym.exists() && !isType(sym) && (pkind & (PCK | TYP)) != 0) {
site = capture(site);
sym = selectSym(tree, site, env, pt, pkind);
}
boolean varArgs = env.info.varArgs;
tree.sym = sym;
DEBUG.P("env.info.varArgs="+env.info.varArgs);
DEBUG.P("tree.sym="+tree.sym);
DEBUG.P("site.tag="+TypeTags.toString(site.tag));
if (site.tag == TYPEVAR && !isType(sym) && sym.kind != ERR)
site = capture(site.getUpperBound());
// If that symbol is a variable, ...
if (sym.kind == VAR) {
VarSymbol v = (VarSymbol)sym;
// ..., evaluate its initializer, if it has one, and check for
// illegal forward reference.
checkInit(tree, env, v, true);
// If we are expecting a variable (as opposed to a value), check
// that the variable is assignable in the current environment.
if (pkind == VAR)
checkAssignable(tree.pos(), v, tree.selected, env);
}
// </editor-fold>
// <editor-fold defaultstate="collapsed">
DEBUG.P("isType(sym)="+isType(sym));
DEBUG.P("sitesym="+sitesym);
if(sitesym!=null) DEBUG.P("sitesym.kind="+Kinds.toString(sitesym.kind));
// Disallow selecting a type from an expression
if (isType(sym) && (sitesym==null || (sitesym.kind&(TYP|PCK)) == 0)) {
tree.type = check(tree.selected, pt,
sitesym == null ? VAL : sitesym.kind, TYP|PCK, pt);
}
DEBUG.P("isType(sitesym)="+isType(sitesym));
if (isType(sitesym)) {
DEBUG.P("sym.name="+sym.name);
if (sym.name == names._this) {
// If `C' is the currently compiled class, check that
// C.this' does not appear in a call to a super(...)
if (env.info.isSelfCall &&
site.tsym == env.enclClass.sym) {
chk.earlyRefError(tree.pos(), sym);
}
} else {
// Check if type-qualified fields or methods are static (JLS)
/*
test\attr\VisitSelectTest.java:15: 无法从类型变量中进行选择
public class VisitSelectTest<T extends B> extends A<T.b> {
^
test\attr\VisitSelectTest.java:15: 无法从类型变量中进行选择
public class VisitSelectTest<T extends B> extends A<T.b> {
^
test\attr\VisitSelectTest.java:19: 无法从静态上下文中引用非静态 变量 b
B b=T.b;
^
test\attr\VisitSelectTest.java:20: 无法从静态上下文中引用非静态 方法 b()
B b2=T.b();
^
4 错误
class A<T>{}
class B {
//int i;
B b;
B b(){ return new B(); }
class b{}
}
public class VisitSelectTest<T extends B> extends A<T.b> {
//A<T.i> al;
//A<T.b> al;
B b=T.b;
B b2=T.b();
}
*/
if ((sym.flags() & STATIC) == 0 &&
sym.name != names._super &&
(sym.kind == VAR || sym.kind == MTH)) {
rs.access(rs.new StaticError(sym),
tree.pos(), site, sym.name, true);
}
}
}
// </editor-fold>
// <editor-fold defaultstate="collapsed">
DEBUG.P("env.info.selectSuper="+env.info.selectSuper);
DEBUG.P("sym.flags_field="+Flags.toString(sym.flags_field));
// If we are selecting an instance member via a `super', ...
if (env.info.selectSuper && (sym.flags() & STATIC) == 0) {
/*
class ClassA<T>{
void m(){};
}
public class VisitSelectTest extends ClassA {
void m() {super.m();} //site.isRaw()=true
}
abstract class ClassA{
abstract void m();
}
public class VisitSelectTest extends ClassA {
void m() {super.m();} //无法直接访问 test.attr.ClassA 中的抽象 方法
}
*/
// Check that super-qualified symbols are not abstract (JLS)
rs.checkNonAbstract(tree.pos(), sym);
DEBUG.P("site="+site);
DEBUG.P("site.isRaw()="+site.isRaw());
if (site.isRaw()) {
// Determine argument types for site.
Type site1 = types.asSuper(env.enclClass.sym.type, site.tsym);
DEBUG.P("(site1 == site)="+(site1 == site));
if (site1 != null) site = site1;
}
}
env.info.selectSuper = selectSuperPrev;
result = checkId(tree, site, sym, env, pkind, pt, varArgs);
env.info.tvars = List.nil();
}finally{//我加上的
DEBUG.P(0,this,"visitSelect(1)");
}
// </editor-fold>
}
//where
/** Determine symbol referenced by a Select expression,
*
* @param tree The select tree.
* @param site The type of the selected expression,
* @param env The current environment.
* @param pt The current prototype.
* @param pkind The expected kind(s) of the Select expression.
*/
private Symbol selectSym(JCFieldAccess tree,
Type site,
Env<AttrContext> env,
Type pt,
int pkind) {
try {//我加上的
DEBUG.P(this,"selectSym(5)");
DEBUG.P("tree="+tree);
DEBUG.P("site="+site);
DEBUG.P("site.tag="+TypeTags.toString(site.tag));
DEBUG.P("env="+env);
DEBUG.P("pt="+pt);
DEBUG.P("pt.tag="+TypeTags.toString(pt.tag));
DEBUG.P("pkind="+Kinds.toString(pkind));
DiagnosticPosition pos = tree.pos();
Name name = tree.name;
DEBUG.P("name="+name);
switch (site.tag) {
case PACKAGE:
return rs.access(
rs.findIdentInPackage(env, site.tsym, name, pkind),
pos, site, name, true);
case ARRAY:
case CLASS:
if (pt.tag == METHOD || pt.tag == FORALL) {
return rs.resolveQualifiedMethod(
pos, env, site, name, pt.getParameterTypes(), pt.getTypeArguments());
//此处不处理像c.super()或c.this()(语法错误)这样的情形
//而是在visitApply(1)中处理
} else if (name == names._this || name == names._super) {
return rs.resolveSelf(pos, env, site.tsym, name);
} else if (name == names._class) {
// In this case, we have already made sure in
// visitSelect that qualifier expression is a type.
Type t = syms.classType;
List<Type> typeargs = allowGenerics
? List.of(types.erasure(site))
: List.<Type>nil();
t = new ClassType(t.getEnclosingType(), typeargs, t.tsym);
return new VarSymbol(
STATIC | PUBLIC | FINAL, names._class, t, site.tsym);
} else {
// We are seeing a plain identifier as selector.
Symbol sym = rs.findIdentInType(env, site, name, pkind);
if ((pkind & ERRONEOUS) == 0)
sym = rs.access(sym, pos, site, name, true);
return sym;
}
case WILDCARD:
throw new AssertionError(tree);
case TYPEVAR:
// Normally, site.getUpperBound() shouldn't be null.
// It should only happen during memberEnter/attribBase
// when determining the super type which *must* be
// done before attributing the type variables. In
// other words, we are seeing this illegal program:
// class B<T> extends A<T.foo> {}
/*
test\attr\VisitSelectTest.java:15: 无法从类型变量中进行选择
public class VisitSelectTest<T extends B> extends A<T.b> {
^
test\attr\VisitSelectTest.java:15: 无法从类型变量中进行选择
public class VisitSelectTest<T extends B> extends A<T.b> {
^
test\attr\VisitSelectTest.java:19: 无法从静态上下文中引用非静态 变量 b
B b=T.b;
^
test\attr\VisitSelectTest.java:20: 无法从静态上下文中引用非静态 方法 b()
B b2=T.b();
^
4 错误
class A<T>{}
class B {
//int i;
B b;
B b(){ return new B(); }
class b{}
}
public class VisitSelectTest<T extends B> extends A<T.b> {
//A<T.i> al;
//A<T.b> al;
B b=T.b;
B b2=T.b();
}
*/
DEBUG.P("site.getUpperBound()="+site.getUpperBound());
Symbol sym = (site.getUpperBound() != null)
? selectSym(tree, capture(site.getUpperBound()), env, pt, pkind)
: null;
DEBUG.P("sym="+sym);
DEBUG.P("selectSym(5) isType(sym)="+isType(sym));
if(sym!=null)DEBUG.P("sym.kind="+Kinds.toString(sym.kind));
/*
class A{
C c;
static class C{
static int i;
}
}
class D<T extends A> {
Class<?> c = T.class;
int i = T.C.i; //isType(sym)=true
A.C c = T.c; //无法从静态上下文中引用非静态 变量 c
}
*/
if (sym == null || isType(sym)) {
log.error(pos, "type.var.cant.be.deref");
return syms.errSymbol;
} else {
return sym;
}
case ERROR:
// preserve identifier names through errors
return new ErrorType(name, site.tsym).tsym;
default:
// The qualifier expression is of a primitive type -- only
// .class is allowed for these.
if (name == names._class) {
// In this case, we have already made sure in Select that
// qualifier expression is a type.
Type t = syms.classType;
Type arg = types.boxedClass(site).type;
t = new ClassType(t.getEnclosingType(), List.of(arg), t.tsym);
return new VarSymbol(
STATIC | PUBLIC | FINAL, names._class, t, site.tsym);
} else {
/*
test\attr\VisitSelectTest.java:8: 无法取消引用 int
int c = t.t;
^
1 错误
void m(int t){
int c = t.t;
}
*/
log.error(pos, "cant.deref", site);
return syms.errSymbol;
}
}
}finally{//我加上的
DEBUG.P(0,this,"selectSym(5)");
}
}
/** Determine type of identifier or select expression and check that
* (1) the referenced symbol is not deprecated
* (2) the symbol's type is safe (@see checkSafe)
* (3) if symbol is a variable, check that its type and kind are
* compatible with the prototype and protokind.
* (4) if symbol is an instance field of a raw type,
* which is being assigned to, issue an unchecked warning if its
* type changes under erasure.
* (5) if symbol is an instance method of a raw type, issue an
* unchecked warning if its argument types change under erasure.
* If checks succeed:
* If symbol is a constant, return its constant type
* else if symbol is a method, return its result type
* otherwise return its type.
* Otherwise return errType.
*
* @param tree The syntax tree representing the identifier
* @param site If this is a select, the type of the selected
* expression, otherwise the type of the current class.
* @param sym The symbol representing the identifier.
* @param env The current environment.
* @param pkind The set of expected kinds.
* @param pt The expected type.
*/
Type checkId(JCTree tree,
Type site,
Symbol sym,
Env<AttrContext> env,
int pkind,
Type pt,
boolean useVarargs) {
try {//我加上的
DEBUG.P(this,"checkId(7)");
DEBUG.P("env="+env);
DEBUG.P("sym="+sym);
DEBUG.P("sym.kind="+Kinds.toString(sym.kind));
if (pt.isErroneous()) return syms.errType;
Type owntype; // The computed type of this identifier occurrence.
switch (sym.kind) {
case TYP:
// <editor-fold defaultstate="collapsed">
// For types, the computed type equals the symbol's type,
// except for two situations:
owntype = sym.type;
DEBUG.P("owntype.tag="+TypeTags.toString(owntype.tag));
if (owntype.tag == CLASS) {
Type ownOuter = owntype.getEnclosingType();
DEBUG.P("ownOuter="+ownOuter);
DEBUG.P("ownOuter.tag="+TypeTags.toString(ownOuter.tag));
DEBUG.P("site="+site);
DEBUG.P("site != ownOuter="+(site != ownOuter));
DEBUG.P("owntype.tsym.type.getTypeArguments()="+owntype.tsym.type.getTypeArguments());
// (a) If the symbol's type is parameterized, erase it
// because no type parameters were given.
// We recover generic outer type later in visitTypeApply.
if (owntype.tsym.type.getTypeArguments().nonEmpty()) {
owntype = types.erasure(owntype);
DEBUG.P("owntype="+owntype);
DEBUG.P("owntype.tag="+TypeTags.toString(owntype.tag));
}
// (b) If the symbol's type is an inner class, then
// we have to interpret its outer type as a superclass
// of the site type. Example:
//
// class Tree<A> { class Visitor { ... } }
// class PointTree extends Tree<Point> { ... }
// ...PointTree.Visitor...
//
// Then the type of the last expression above is
// Tree<Point>.Visitor.
else if (ownOuter.tag == CLASS && site != ownOuter) {
Type normOuter = site;
DEBUG.P("site="+site);
DEBUG.P("ownOuter="+ownOuter);
DEBUG.P("ownOuter.tsym="+ownOuter.tsym);
DEBUG.P("normOuter.tag="+TypeTags.toString(normOuter.tag));
if (normOuter.tag == CLASS)
normOuter = types.asEnclosingSuper(site, ownOuter.tsym);
DEBUG.P("normOuter="+normOuter);
if (normOuter == null) // perhaps from an import
normOuter = types.erasure(ownOuter);
DEBUG.P("normOuter="+normOuter);
DEBUG.P("ownOuter ="+ownOuter);
DEBUG.P("normOuter != ownOuter="+(normOuter != ownOuter));
if (normOuter != ownOuter)
owntype = new ClassType(
normOuter, List.<Type>nil(), owntype.tsym);
DEBUG.P("owntype="+owntype);
DEBUG.P("owntype.tag="+TypeTags.toString(owntype.tag));
}
}
break;
// </editor-fold>
case VAR:
// <editor-fold defaultstate="collapsed">
VarSymbol v = (VarSymbol)sym;
// Test (4): if symbol is an instance field of a raw type,
// which is being assigned to, issue an unchecked warning if
// its type changes under erasure.
if (allowGenerics &&
pkind == VAR &&
v.owner.kind == TYP &&
(v.flags() & STATIC) == 0 &&
(site.tag == CLASS || site.tag == TYPEVAR)) {
Type s = types.asOuterSuper(site, v.owner);
if (s != null &&
s.isRaw() &&
!types.isSameType(v.type, v.erasure(types))) {
chk.warnUnchecked(tree.pos(),
"unchecked.assign.to.var",
v, s);
}
}
// The computed type of a variable is the type of the
// variable symbol, taken as a member of the site type.
owntype = (sym.owner.kind == TYP &&
sym.name != names._this && sym.name != names._super)
? types.memberType(site, sym)
: sym.type;
if (env.info.tvars.nonEmpty()) {
Type owntype1 = new ForAll(env.info.tvars, owntype);
for (List<Type> l = env.info.tvars; l.nonEmpty(); l = l.tail)
if (!owntype.contains(l.head)) {
log.error(tree.pos(), "undetermined.type", owntype1);
owntype1 = syms.errType;
}
owntype = owntype1;
}
// If the variable is a constant, record constant value in
// computed type.
if (v.getConstValue() != null && isStaticReference(tree))
owntype = owntype.constType(v.getConstValue());
if (pkind == VAL) {
owntype = capture(owntype); // capture "names as expressions"
}
break;
// </editor-fold>
case MTH: {
JCMethodInvocation app = (JCMethodInvocation)env.tree;
owntype = checkMethod(site, sym, env, app.args,
pt.getParameterTypes(), pt.getTypeArguments(),
env.info.varArgs);
break;
}
case PCK: case ERR:
owntype = sym.type;
DEBUG.P("owntype.tag="+TypeTags.toString(owntype.tag));
break;
default:
throw new AssertionError("unexpected kind: " + sym.kind +
" in tree " + tree);
}
DEBUG.P("sym.flags_field="+Flags.toString(sym.flags_field));
// Test (1): emit a `deprecation' warning if symbol is deprecated.
// (for constructors, the error was given when the constructor was
// resolved)
if (sym.name != names.init &&
(sym.flags() & DEPRECATED) != 0 &&
(env.info.scope.owner.flags() & DEPRECATED) == 0 &&
sym.outermostClass() != env.info.scope.owner.outermostClass())
chk.warnDeprecated(tree.pos(), sym);
if ((sym.flags() & PROPRIETARY) != 0)
log.strictWarning(tree.pos(), "sun.proprietary", sym);
// Test (3): if symbol is a variable, check that its type and
// kind are compatible with the prototype and protokind.
return check(tree, owntype, sym.kind, pkind, pt);
}finally{//我加上的
DEBUG.P(0,this,"checkId(7)");
}
}
/** Check that variable is initialized and evaluate the variable's
* initializer, if not yet done. Also check that variable is not
* referenced before it is defined.
* @param tree The tree making up the variable reference.
* @param env The current environment.
* @param v The variable's symbol.
*/
private void checkInit(JCTree tree,
Env<AttrContext> env,
VarSymbol v,
boolean onlyWarning) {
DEBUG.P(this,"checkInit(4)");
DEBUG.P("tree="+tree);
DEBUG.P("v="+v);
DEBUG.P("onlyWarning="+onlyWarning);
DEBUG.P("v.pos="+v.pos);
DEBUG.P("tree.pos="+tree.pos);
DEBUG.P("v.owner.kind="+Kinds.toString(v.owner.kind));
// System.err.println(v + " " + ((v.flags() & STATIC) != 0) + " " +
// tree.pos + " " + v.pos + " " +
// Resolve.isStatic(env));//DEBUG
// A forward reference is diagnosed if the declaration position
// of the variable is greater than the current tree position
// and the tree and variable definition occur in the same class
// definition. Note that writes don't count as references.
// This check applies only to class and instance
// variables. Local variables follow different scope rules,
// and are subject to definite assignment checking.
if (v.pos > tree.pos &&
v.owner.kind == TYP &&
canOwnInitializer(env.info.scope.owner) &&
v.owner == env.info.scope.owner.enclClass() &&
((v.flags() & STATIC) != 0) == Resolve.isStatic(env) &&
(env.tree.tag != JCTree.ASSIGN ||
TreeInfo.skipParens(((JCAssign) env.tree).lhs) != tree)) {
if (!onlyWarning || isNonStaticEnumField(v)) {
log.error(tree.pos(), "illegal.forward.ref");
} else if (useBeforeDeclarationWarning) {
log.warning(tree.pos(), "forward.ref", v);
}
}
v.getConstValue(); // ensure initializer is evaluated
checkEnumInitializer(tree, env, v);
DEBUG.P(0,this,"checkInit(4)");
}
/**
* Check for illegal references to static members of enum. In
* an enum type, constructors and initializers may not
* reference its static members unless they are constant.
*
* @param tree The tree making up the variable reference.
* @param env The current environment.
* @param v The variable's symbol.
* @see JLS 3rd Ed. (8.9 Enums)
*/
private void checkEnumInitializer(JCTree tree, Env<AttrContext> env, VarSymbol v) {
// JLS 3rd Ed.:
//
// "It is a compile-time error to reference a static field
// of an enum type that is not a compile-time constant
// (15.28) from constructors, instance initializer blocks,
// or instance variable initializer expressions of that
// type. It is a compile-time error for the constructors,
// instance initializer blocks, or instance variable
// initializer expressions of an enum constant e to refer
// to itself or to an enum constant of the same type that
// is declared to the right of e."
if (isNonStaticEnumField(v)) {
ClassSymbol enclClass = env.info.scope.owner.enclClass();
if (enclClass == null || enclClass.owner == null)
return;
// See if the enclosing class is the enum (or a
// subclass thereof) declaring v. If not, this
// reference is OK.
if (v.owner != enclClass && !types.isSubtype(enclClass.type, v.owner.type))
return;
// If the reference isn't from an initializer, then
// the reference is OK.
if (!Resolve.isInitializer(env))
return;
log.error(tree.pos(), "illegal.enum.static.ref");
}
}
private boolean isNonStaticEnumField(VarSymbol v) {
return Flags.isEnum(v.owner) && Flags.isStatic(v) && !Flags.isConstant(v);
}
/** Can the given symbol be the owner of code which forms part
* if class initialization? This is the case if the symbol is
* a type or field, or if the symbol is the synthetic method.
* owning a block.
*/
private boolean canOwnInitializer(Symbol sym) {
return
(sym.kind & (VAR | TYP)) != 0 ||
(sym.kind == MTH && (sym.flags() & BLOCK) != 0);
}
Warner noteWarner = new Warner();
/**
* Check that method arguments conform to its instantation.
**/
public Type checkMethod(Type site,
Symbol sym,
Env<AttrContext> env,
final List<JCExpression> argtrees,
List<Type> argtypes,
List<Type> typeargtypes,
boolean useVarargs) {
DEBUG.P(this,"checkMethod(7)");
DEBUG.P("site="+site);
DEBUG.P("sym="+sym);
DEBUG.P("argtrees="+argtrees);
DEBUG.P("argtypes="+argtypes);
DEBUG.P("typeargtypes="+typeargtypes);
DEBUG.P("useVarargs="+useVarargs);
// Test (5): if symbol is an instance method of a raw type, issue
// an unchecked warning if its argument types change under erasure.
if (allowGenerics &&
(sym.flags() & STATIC) == 0 &&
(site.tag == CLASS || site.tag == TYPEVAR)) {
/*如:
class VisitNewClassTest<T> {
VisitNewClassTest vct = new VisitNewClassTest(this);
VisitNewClassTest(VisitNewClassTest<T> t){}
}
*/
Type s = types.asOuterSuper(site, sym.owner);
if (s != null && s.isRaw() &&
!types.isSameTypes(sym.type.getParameterTypes(),
sym.erasure(types).getParameterTypes())) {
chk.warnUnchecked(env.tree.pos(),
"unchecked.call.mbr.of.raw.type",
sym, s);
}
}
// Compute the identifier's instantiated type.
// For methods, we need to compute the instance type by
// Resolve.instantiate from the symbol's type as well as
// any type arguments and value arguments.
noteWarner.warned = false;
Type owntype = rs.instantiate(env,
site,
sym,
argtypes,
typeargtypes,
true,
useVarargs,
noteWarner);
boolean warned = noteWarner.warned;
// If this fails, something went wrong; we should not have
// found the identifier in the first place.
if (owntype == null) {
if (!pt.isErroneous())
log.error(env.tree.pos(),
"internal.error.cant.instantiate",
sym, site,
Type.toString(pt.getParameterTypes()));
owntype = syms.errType;
} else {
// System.out.println("call : " + env.tree);
// System.out.println("method : " + owntype);
// System.out.println("actuals: " + argtypes);
List<Type> formals = owntype.getParameterTypes();
Type last = useVarargs ? formals.last() : null;
if (sym.name==names.init &&
sym.owner == syms.enumSym)
formals = formals.tail.tail;
List<JCExpression> args = argtrees;
while (formals.head != last) {
JCTree arg = args.head;
Warner warn = chk.convertWarner(arg.pos(), arg.type, formals.head);
assertConvertible(arg, arg.type, formals.head, warn);
warned |= warn.warned;
args = args.tail;
formals = formals.tail;
}
if (useVarargs) {
Type varArg = types.elemtype(last);
while (args.tail != null) {
JCTree arg = args.head;
Warner warn = chk.convertWarner(arg.pos(), arg.type, varArg);
assertConvertible(arg, arg.type, varArg, warn);
warned |= warn.warned;
args = args.tail;
}
} else if ((sym.flags() & VARARGS) != 0 && allowVarargs) {
// non-varargs call to varargs method
Type varParam = owntype.getParameterTypes().last();
Type lastArg = argtypes.last();
if (types.isSubtypeUnchecked(lastArg, types.elemtype(varParam)) &&
!types.isSameType(types.erasure(varParam), types.erasure(lastArg)))
log.warning(argtrees.last().pos(), "inexact.non-varargs.call",
types.elemtype(varParam),
varParam);
}
if (warned && sym.type.tag == FORALL) {
String typeargs = "";
if (typeargtypes != null && typeargtypes.nonEmpty()) {
typeargs = "<" + Type.toString(typeargtypes) + ">";
}
chk.warnUnchecked(env.tree.pos(),
"unchecked.meth.invocation.applied",
sym,
sym.location(),
typeargs,
Type.toString(argtypes));
owntype = new MethodType(owntype.getParameterTypes(),
types.erasure(owntype.getReturnType()),
owntype.getThrownTypes(),
syms.methodClass);
}
if (useVarargs) {
JCTree tree = env.tree;
Type argtype = owntype.getParameterTypes().last();
if (!types.isReifiable(argtype))
chk.warnUnchecked(env.tree.pos(),
"unchecked.generic.array.creation",
argtype);
Type elemtype = types.elemtype(argtype);
switch (tree.tag) {
case JCTree.APPLY:
((JCMethodInvocation) tree).varargsElement = elemtype;
break;
case JCTree.NEWCLASS:
((JCNewClass) tree).varargsElement = elemtype;
break;
default:
throw new AssertionError(""+tree);
}
}
}
DEBUG.P("owntype="+owntype);
DEBUG.P(0,this,"checkMethod(7)");
return owntype;
}
private void assertConvertible(JCTree tree, Type actual, Type formal, Warner warn) {
if (types.isConvertible(actual, formal, warn))
return;
if (formal.isCompound()
&& types.isSubtype(actual, types.supertype(formal))
&& types.isSubtypeUnchecked(actual, types.interfaces(formal), warn))
return;
if (false) {
// TODO: make assertConvertible work
chk.typeError(tree.pos(), JCDiagnostic.fragment("incompatible.types"), actual, formal);
throw new AssertionError("Tree: " + tree
+ " actual:" + actual
+ " formal: " + formal);
}
}
public void visitLiteral(JCLiteral tree) {
DEBUG.P(this,"visitLiteral(1)");
DEBUG.P("tree="+tree);
result = check(
tree, litType(tree.typetag).constType(tree.value), VAL, pkind, pt);
if(result!=null) {
DEBUG.P("result="+result);
DEBUG.P("result.constValue()="+result.constValue());
}
DEBUG.P(0,this,"visitLiteral(1)");
}
//where
/** Return the type of a literal with given type tag.
*/
Type litType(int tag) {
return (tag == TypeTags.CLASS) ? syms.stringType : syms.typeOfTag[tag];
}
//原始类型名，如int long等等，
public void visitTypeIdent(JCPrimitiveTypeTree tree) {
DEBUG.P(this,"visitTypeIdent(JCPrimitiveTypeTree tree)");
DEBUG.P("tree="+tree);
result = check(tree, syms.typeOfTag[tree.typetag], TYP, pkind, pt);
DEBUG.P(0,this,"visitTypeIdent(JCPrimitiveTypeTree tree)");
}
//如:int[]
public void visitTypeArray(JCArrayTypeTree tree) {
DEBUG.P(this,"visitTypeArray(JCArrayTypeTree tree)");
DEBUG.P("tree="+tree);
Type etype = attribType(tree.elemtype, env);
Type type = new ArrayType(etype, syms.arrayClass);
result = check(tree, type, TYP, pkind, pt);
DEBUG.P(0,this,"visitTypeArray(JCArrayTypeTree tree)");
}
/** Visitor method for parameterized types.
* Bound checking is left until later, since types are attributed
* before supertype structure is completely known
*/
//如:List<String>
public void visitTypeApply(JCTypeApply tree) {
DEBUG.P(this,"visitTypeApply(1)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.clazz="+tree.clazz);
DEBUG.P("tree.arguments="+tree.arguments);
Type owntype = syms.errType;
// Attribute functor part of application and make sure it's a class.
Type clazztype = chk.checkClassType(tree.clazz.pos(), attribType(tree.clazz, env));
// Attribute type parameters
List<Type> actuals = attribTypes(tree.arguments, env);
DEBUG.P("");
DEBUG.P("actuals="+actuals);
DEBUG.P("clazztype="+clazztype);
DEBUG.P("clazztype.tag="+TypeTags.toString(clazztype.tag));
if (clazztype.tag == CLASS) {
List<Type> formals = clazztype.tsym.type.getTypeArguments();
DEBUG.P("formals="+formals);
DEBUG.P("actuals.length()="+actuals.length());
DEBUG.P("formals.length()="+formals.length());
if (actuals.length() == formals.length()) {
List<Type> a = actuals;
List<Type> f = formals;
while (a.nonEmpty()) {
/*如:
class Aclass<T> {
Aclass<?> a;
}
com.sun.tools.javac.code.Type$WildcardType===>withTypeVar(Type t)
-------------------------------------------------------------------------
bound=null
t =T {bound=Object}
泛型类形参：T {bound=Object}
泛型类实参：?
com.sun.tools.javac.code.Type$WildcardType===>withTypeVar(Type t) END
-------------------------------------------------------------------------
*/
a.head = a.head.withTypeVar(f.head);//只对WildcardType有用
a = a.tail;
f = f.tail;
}
// Compute the proper generic outer
Type clazzOuter = clazztype.getEnclosingType();
DEBUG.P("");
DEBUG.P("clazzOuter="+clazzOuter);
DEBUG.P("clazzOuter.tag="+TypeTags.toString(clazzOuter.tag));
if (clazzOuter.tag == CLASS) {
DEBUG.P("tree.clazz="+tree.clazz);
DEBUG.P("tree.clazz.tag="+tree.clazz.myTreeTag());
DEBUG.P("env="+env);
Type site;
if (tree.clazz.tag == JCTree.IDENT) {
site = env.enclClass.sym.type;
} else if (tree.clazz.tag == JCTree.SELECT) {
site = ((JCFieldAccess) tree.clazz).selected.type;
} else throw new AssertionError(""+tree);
DEBUG.P("site="+site);
DEBUG.P("site.tag="+TypeTags.toString(site.tag));
DEBUG.P("(clazzOuter.tag == CLASS && site != clazzOuter)="+(clazzOuter.tag == CLASS && site != clazzOuter));
/*例:
import test.attr.Aclass.*;
class Aclass<T> {
class Bclass<V>{
//site=test.attr.Aclass<T {bound=Object}>.Bclass<V {bound=Object}>
//site.tag=CLASS
(clazzOuter.tag == CLASS && site != clazzOuter)=true
//site=test.attr.Aclass<T {bound=Object}>
//clazzOuter=test.attr.Aclass
//clazzOuter=test.attr.Aclass<T {bound=Object}>
Bclass<Aclass3> b1;
}
}
class Aclass2<T> {
//类型的格式不正确，给出了普通类型的类型参数
//因为import中导入的Aclass不带参数，
//相当于“Aclass.Bclass<Aclass3> b2;”这样的格式是错误的
//site = types.asOuterSuper(site, clazzOuter.tsym)=null
//最后clazzOuter=test.attr.Aclass
Bclass<Aclass3> b2;
//第一个clazzOuter=test.attr.Aclass，
//但是site=test.attr.Aclass<test.attr.Aclass3>
//所以(clazzOuter.tag == CLASS && site != clazzOuter)=true
//接着site = types.asOuterSuper(site, clazzOuter.tsym);
//返回site=test.attr.Aclass<test.attr.Aclass3>
//最后clazzOuter=test.attr.Aclass<test.attr.Aclass3>
Aclass<Aclass3>.Bclass<Aclass3> b3;
}
class Aclass3{}
*/
if (clazzOuter.tag == CLASS && site != clazzOuter) {
if (site.tag == CLASS)
site = types.asOuterSuper(site, clazzOuter.tsym);
DEBUG.P("site="+site);
DEBUG.P("clazzOuter="+clazzOuter);
if (site == null)
site = types.erasure(clazzOuter);
clazzOuter = site;
}
}
DEBUG.P("clazzOuter="+clazzOuter);
owntype = new ClassType(clazzOuter, actuals, clazztype.tsym);
} else {
if (formals.length() != 0) {
/*例子:
class ExtendsTest<T,S,B> {}
public class MyTestInnerClass
<Z extends ExtendsTest<?,? super ExtendsTest>>
错误提示(中文):
bin\mysrc\my\test\Test.java:8: 类型变量数目错误；需要 3
MyTestInnerClass<Z extends ExtendsTest<?,? super ExtendsTest>>
^
错误提示(英文):
bin\mysrc\my\test\Test.java:8: wrong number of type arguments; required 3
MyTestInnerClass<Z extends ExtendsTest<?,? super ExtendsTest>>
^
注:中文错误提示翻译不准确,“type arguments”不能翻译成“类型变量”，
“类型变量”是特指泛型类定义中的“类型变量”，如Test<T>，“T”就是
一个“类型变量”，而“type arguments”是指参数化后的泛型类的参数，
如Test<String>，String就是一个“type argument”，所以准确一点的
翻译应该是“类型参数数目错误”。
*/
log.error(tree.pos(), "wrong.number.type.args",
Integer.toString(formals.length()));
} else {
/*例子:
class ExtendsTest{}
public class MyTestInnerClass
<Z extends ExtendsTest<?,? super ExtendsTest>>
错误提示(中文):
bin\mysrc\my\test\Test.java:8: 类型 my.test.ExtendsTest 不带有参数
MyTestInnerClass<Z extends ExtendsTest<?,? super ExtendsTest>>
^
错误提示(英文):
bin\mysrc\my\test\Test.java:8: type my.test.ExtendsTest does not take parameters
MyTestInnerClass<Z extends ExtendsTest<?,? super ExtendsTest>>
^
*/
log.error(tree.pos(), "type.doesnt.take.params", clazztype.tsym);
}
owntype = syms.errType;
}
}
result = check(tree, owntype, TYP, pkind, pt);
DEBUG.P("tree.type="+tree.type);
DEBUG.P("tree.type.tsym.type="+tree.type.tsym.type);
DEBUG.P(0,this,"visitTypeApply(1)");
}
//b10
public void visitTypeParameter(JCTypeParameter tree) {
try {//我加上的
DEBUG.P(this,"visitTypeParameter(1)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.type.tag="+TypeTags.toString(tree.type.tag));
DEBUG.P("tree.bounds="+tree.bounds);
TypeVar a = (TypeVar)tree.type;
Set<Type> boundSet = new HashSet<Type>();
DEBUG.P("a.bound.isErroneous()="+a.bound.isErroneous());
if (a.bound.isErroneous())
return;
List<Type> bs = types.getBounds(a);
if (tree.bounds.nonEmpty()) {
// accept class or interface or typevar as first bound.
Type b = checkBase(bs.head, tree.bounds.head, env, false, false, false);
boundSet.add(types.erasure(b));
DEBUG.P("b.tag="+TypeTags.toString(b.tag));
if (b.tag == TYPEVAR) {
/*错误例子:
bin\mysrc\my\test\Test.java:8: 类型变量后面不能带有其他限制范围
public class Test<S,T extends ExtendsTest,E extends S & MyInterfaceA> extends my
.ExtendsTest.MyInnerClassStatic {
^
*/
// if first bound was a typevar, do not accept further bounds.
if (tree.bounds.tail.nonEmpty()) {
log.error(tree.bounds.tail.head.pos(),
"type.var.may.not.be.followed.by.other.bounds");
tree.bounds = List.of(tree.bounds.head);
}
} else {
// if first bound was a class or interface, accept only interfaces
// as further bounds.
for (JCExpression bound : tree.bounds.tail) {
bs = bs.tail;
Type i = checkBase(bs.head, bound, env, false, true, false);
if (i.tag == CLASS)
chk.checkNotRepeated(bound.pos(), types.erasure(i), boundSet);
}
}
}
bs = types.getBounds(a);
//对于TF extends TA&InterfaceA,TG extends SuperClassA & InterfaceA & TB
//这样的复合类型不管对不对，这里都生成一个JCClassDecl
DEBUG.P("bs="+bs);
DEBUG.P("bs.length()="+bs.length());
// in case of multiple bounds ...
if (bs.length() > 1) {
// ... the variable's bound is a class type flagged COMPOUND
// (see comment for TypeVar.bound).
// In this case, generate a class tree that represents the
// bound class, ...
JCTree extending;
List<JCExpression> implementing;
if ((bs.head.tsym.flags() & INTERFACE) == 0) {
extending = tree.bounds.head;
implementing = tree.bounds.tail;
} else {
extending = null;
implementing = tree.bounds;
}
DEBUG.P("tree.name="+tree.name);
DEBUG.P("a.getUpperBound()="+a.getUpperBound());
JCClassDecl cd = make.at(tree.pos).ClassDef(
make.Modifiers(PUBLIC | ABSTRACT),
tree.name, List.<JCTypeParameter>nil(),
extending, implementing, List.<JCTree>nil());
ClassSymbol c = (ClassSymbol)a.getUpperBound().tsym;
assert (c.flags() & COMPOUND) != 0;
cd.sym = c;
c.sourcefile = env.toplevel.sourcefile;
// ... and attribute the bound class
c.flags_field |= UNATTRIBUTED;
Env<AttrContext> cenv = enter.classEnv(cd, env);
enter.typeEnvs.put(c, cenv);
DEBUG.P("cenv="+cenv);
DEBUG.P("c="+c);
/*
DEBUG.P("");
DEBUG.P("Env总数: "+enter.typeEnvs.size());
DEBUG.P("--------------------------");
for(Map.Entry<TypeSymbol,Env<AttrContext>> myMapEntry:enter.typeEnvs.entrySet())
DEBUG.P(""+myMapEntry);
DEBUG.P("");
*/
}
}finally{//我加上的
DEBUG.P(0,this,"visitTypeParameter(1)");
}
}
public void visitWildcard(JCWildcard tree) {
DEBUG.P(this,"visitWildcard(1)");
DEBUG.P("tree="+tree);
DEBUG.P("tree.kind="+tree.kind);
DEBUG.P("tree.inner="+tree.inner);
//- System.err.println("visitWildcard("+tree+");");//DEBUG
Type type = (tree.kind.kind == BoundKind.UNBOUND)
? syms.objectType
: attribType(tree.inner, env);
result = check(tree, new WildcardType(chk.checkRefType(tree.pos(), type),
tree.kind.kind,
syms.boundClass),
TYP, pkind, pt);
DEBUG.P(0,this,"visitWildcard(1)");
}
public void visitAnnotation(JCAnnotation tree) {
log.error(tree.pos(), "annotation.not.valid.for.type", pt);
result = tree.type = syms.errType;
}
public void visitErroneous(JCErroneous tree) {
if (tree.errs != null)
for (JCTree err : tree.errs)
attribTree(err, env, ERR, pt);
result = tree.type = syms.errType;
}
/** Default visitor method for all other trees.
*/
public void visitTree(JCTree tree) {
throw new AssertionError();
}
/** Main method: attribute class definition associated with given class symbol.
* reporting completion failures at the given position.
* @param pos The source position at which completion errors are to be
* reported.
* @param c The class symbol whose definition will be attributed.
*/
public void attribClass(DiagnosticPosition pos, ClassSymbol c) {
DEBUG.P(5);DEBUG.P(this,"attribClass(2)");
try {
annotate.flush();
attribClass(c);
} catch (CompletionFailure ex) {
chk.completionError(pos, ex);
}
DEBUG.P(2,this,"attribClass(2)");
}
/** Attribute class definition associated with given class symbol.
* @param c The class symbol whose definition will be attributed.
*/
void attribClass(ClassSymbol c) throws CompletionFailure {
try {//我加上的
DEBUG.P(this,"attribClass(1)");
DEBUG.P("ClassSymbol c="+c);
DEBUG.P("c.type="+c.type);
DEBUG.P("c.type.tag="+TypeTags.toString(c.type.tag));
DEBUG.P("c.type.supertype="+((ClassType)c.type).supertype_field);
//编译package-info.java时有错java.lang.NullPointerException
//DEBUG.P("c.type.supertype.tag="+TypeTags.toString((((ClassType)c.type).supertype_field).tag));
if (c.type.tag == ERROR) return;
// Check for cycles in the inheritance graph, which can arise from
// ill-formed class files.
chk.checkNonCyclic(null, c.type);
//检查类(或接口)是否自己继承(或实现)自己，是否彼此之间互相继承(或实现)
//如Test4 extends Test4(自己继承自己)
//如Test4 extends Test5且Test5 extends Test4(彼此之间互相继承)
//如:public class Test4 extends Test4
//报错:cyclic inheritance involving my.test.Test4
Type st = types.supertype(c.type);
DEBUG.P("c.flags_field="+Flags.toString(c.flags_field));
DEBUG.P("c.supertype="+st);
DEBUG.P("c.supertype.tag="+TypeTags.toString(st.tag));
DEBUG.P("c.owner="+c.owner);
DEBUG.P("c.owner.kind="+Kinds.toString(c.owner.kind));
if(c.owner.type!=null) DEBUG.P("c.owner.type.tag="+TypeTags.toString(c.owner.type.tag));
//c.flags_field不包含Flags.COMPOUND时执行
if ((c.flags_field & Flags.COMPOUND) == 0) {
DEBUG.P("c.flags_field不包含Flags.COMPOUND");
// First, attribute superclass.
if (st.tag == CLASS)
attribClass((ClassSymbol)st.tsym);
// Next attribute owner, if it is a class.
if (c.owner.kind == TYP && c.owner.type.tag == CLASS)
attribClass((ClassSymbol)c.owner);
}
DEBUG.P("完成对："+c+" 的superclass及owner的attribute");
DEBUG.P("c.flags_field="+Flags.toString(c.flags_field));
// The previous operations might have attributed the current class
// if there was a cycle. So we test first whether the class is still
// UNATTRIBUTED.
if ((c.flags_field & UNATTRIBUTED) != 0) {
//这条语句很有用，因为如果对c这个类进行attribClass后，
//在c.flags_field中就没有UNATTRIBUTED这个标志了，当其他
//类的超类是c时，在调用Check.checkNonCyclic方法检测循环时，
//就可以把ACYCLIC标志加进c.flags_field中。
c.flags_field &= ~UNATTRIBUTED;
// Get environment current at the point of class definition.
Env<AttrContext> env = enter.typeEnvs.get(c);
DEBUG.P("c.flags_field="+Flags.toString(c.flags_field));
DEBUG.P("env="+env);
// The info.lint field in the envs stored in enter.typeEnvs is deliberately uninitialized,
// because the annotations were not available at the time the env was created. Therefore,
// we look up the environment chain for the first enclosing environment for which the
// lint value is set. Typically, this is the parent env, but might be further if there
// are any envs created as a result of TypeParameter nodes.
Env<AttrContext> lintEnv = env;
while (lintEnv.info.lint == null)
lintEnv = lintEnv.next;
DEBUG.P("lintEnv="+lintEnv);
// Having found the enclosing lint value, we can initialize the lint value for this class
env.info.lint = lintEnv.info.lint.augment(c.attributes_field, c.flags());
DEBUG.P("env.info.lint="+env.info.lint);
Lint prevLint = chk.setLint(env.info.lint);
JavaFileObject prev = log.useSource(c.sourcefile);
try {
DEBUG.P("");
DEBUG.P("st.tsym="+st.tsym);
if (st.tsym != null)
DEBUG.P("st.tsym.flags_field="+Flags.toString(st.tsym.flags_field));
DEBUG.P("c.flags_field="+Flags.toString(c.flags_field));
// java.lang.Enum may not be subclassed by a non-enum
if (st.tsym == syms.enumSym &&
((c.flags_field & (Flags.ENUM|Flags.COMPOUND)) == 0))
/*例子:
F:\javac\bin\mysrc\my\test\TestOhter.java:2: 类无法直接继承 java.lang.Enum
public class TestOhter<TestOhterS,TestOhterT> extends Enum {
^
1 错误
*/
log.error(env.tree.pos(), "enum.no.subclassing");
// Enums may not be extended by source-level classes
//注:如果((c.flags_field & Flags.ENUM) == 0)为true，那么
//target.compilerBootstrap(c)总是为fasle的，也就是
//!target.compilerBootstrap(c)总是为true，这条件是多余的判断
if (st.tsym != null &&
((st.tsym.flags_field & Flags.ENUM) != 0) &&
((c.flags_field & Flags.ENUM) == 0) &&
!target.compilerBootstrap(c)) {
/*例子:
源代码:
package my.test.myenum;
public class EnumTest extends MyEnum {}
enum MyEnum {}
错误提示:
bin\mysrc\my\test\myenum\EnumTest.java:3: 无法从最终 my.test.myenum.MyEnum 进行继承
public class EnumTest extends MyEnum {}
^
bin\mysrc\my\test\myenum\EnumTest.java:3: 枚举类型不可继承
public class EnumTest extends MyEnum {}
^
2 错误
*/
log.error(env.tree.pos(), "enum.types.not.extensible");
}
DEBUG.P(2);
attribClassBody(env, c);
chk.checkDeprecatedAnnotation(env.tree.pos(), c);
} finally {
log.useSource(prev);
chk.setLint(prevLint);
}
}
}finally{//我加上的
DEBUG.P("结束对此类的属性分性: "+c);
DEBUG.P(1,this,"attribClass(1)");
}
}
public void visitImport(JCImport tree) {
// nothing to do
}
/** Finish the attribution of a class. */
private void attribClassBody(Env<AttrContext> env, ClassSymbol c) {
DEBUG.P(this,"attribClassBody(2)");
DEBUG.P("ClassSymbol c="+c);
DEBUG.P("env="+env);
JCClassDecl tree = (JCClassDecl)env.tree;
assert c == tree.sym;
// Validate annotations
chk.validateAnnotations(tree.mods.annotations, c);
// Validate type parameters, supertype and interfaces.
attribBounds(tree.typarams);//对COMPOUND型的上限绑定进行attribClass
/*
主要是检查同一泛型类的参数化类型之间的差别
如泛型类定义 :interface Test<T extends Number>
参数化类型t :Test<Number>
参数化类型s :Test<? super Float>
当定义新的泛型类：Test2<S extends Test<Number>&Test<? super Float>>
时，在validateTypeParams中能检查出“无法使用以下不同的参数继承”错误
*/
chk.validateTypeParams(tree.typarams);
chk.validate(tree.extending);
chk.validate(tree.implementing);
DEBUG.P(2);DEBUG.P("结束:Validate annotations, type parameters, supertype and interfaces : "+c);DEBUG.P(2);
DEBUG.P("relax="+relax);
DEBUG.P("c.flags()="+Flags.toString(c.flags()));
// If this is a non-abstract class, check that it has no abstract
// methods or unimplemented methods of an implemented interface.
if ((c.flags() & (ABSTRACT | INTERFACE)) == 0) {
if (!relax)
chk.checkAllDefined(tree.pos(), c);
}
if ((c.flags() & ANNOTATION) != 0) {
if (tree.implementing.nonEmpty())
log.error(tree.implementing.head.pos(),
"cant.extend.intf.annotation");
if (tree.typarams.nonEmpty())
log.error(tree.typarams.head.pos(),
"intf.annotation.cant.have.type.params");
} else {
// Check that all extended classes and interfaces
// are compatible (i.e. no two define methods with same arguments
// yet different return types). (JLS 8.4.6.3)
chk.checkCompatibleSupertypes(tree.pos(), c.type);
}
// Check that class does not import the same parameterized interface
// with two different argument lists.
chk.checkClassBounds(tree.pos(), c.type);
tree.type = c.type;
boolean assertsEnabled = false;
assert assertsEnabled = true;
DEBUG.P("env.info.scope="+env.info.scope);
if (assertsEnabled) {
for (List<JCTypeParameter> l = tree.typarams;
l.nonEmpty(); l = l.tail)
assert env.info.scope.lookup(l.head.name).scope != null;
}
DEBUG.P("c.type="+c.type);
DEBUG.P("c.type.allparams()="+c.type.allparams());
/*错误例子:
bin\mysrc\my\test\Test.java:7: 泛型类无法继承 java.lang.Throwable
public class Test<S,T extends ExtendsTest,E extends ExtendsTest & MyInterfaceA>
extends Exception {
^
1 错误
*/
// Check that a generic class doesn't extend Throwable
if (!c.type.allparams().isEmpty() && types.isSubtype(c.type, syms.throwableType))
log.error(tree.extending.pos(), "generic.throwable");
// Check that all methods which implement some
// method conform to the method they implement.
chk.checkImplementations(tree);
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
// Attribute declaration
attribStat(l.head, env);
// Check that declarations in inner classes are not static (JLS 8.1.2)
// Make an exception for static constants.
if (c.owner.kind != PCK &&
((c.flags() & STATIC) == 0 || c.name == names.empty) &&
(TreeInfo.flags(l.head) & (STATIC | INTERFACE)) != 0) {
Symbol sym = null;
if (l.head.tag == JCTree.VARDEF) sym = ((JCVariableDecl) l.head).sym;
if (sym == null ||
sym.kind != VAR ||
((VarSymbol) sym).getConstValue() == null)
log.error(l.head.pos(), "icls.cant.have.static.decl");
}
}
// Check for cycles among non-initial constructors.
chk.checkCyclicConstructors(tree);
// Check for cycles among annotation elements.
chk.checkNonCyclicElements(tree);
// Check for proper use of serialVersionUID
if (env.info.lint.isEnabled(Lint.LintCategory.SERIAL) &&
isSerializable(c) &&
(c.flags() & Flags.ENUM) == 0 &&
(c.flags() & ABSTRACT) == 0) {
checkSerialVersionUID(tree, c);
}
DEBUG.P(0,this,"attribClassBody(2)");
}
// where
/** check if a class is a subtype of Serializable, if that is available. */
//注:任何java.lang.Throwable的子类都是可序列化的，因为
//java.lang.Throwable实现了java.io.Serializable接中。
private boolean isSerializable(ClassSymbol c) {
try {
syms.serializableType.complete();
}
catch (CompletionFailure e) {
return false;
}
return types.isSubtype(c.type, syms.serializableType);
}
/** Check that an appropriate serialVersionUID member is defined. */
private void checkSerialVersionUID(JCClassDecl tree, ClassSymbol c) {
//如果一个类直接或间接实现了java.io.Serializable接中，在这个类中需要
//定义一个“static final long serialVersionUID”字段，且这个字段还必需
//显示赋值，否则，只要其中一点不符合，编译器就给出警告。
// check for presence of serialVersionUID
Scope.Entry e = c.members().lookup(names.serialVersionUID);
while (e.scope != null && e.sym.kind != VAR) e = e.next();
if (e.scope == null) {
log.warning(tree.pos(), "missing.SVUID", c);
return;
}
// check that it is static final
VarSymbol svuid = (VarSymbol)e.sym;
if ((svuid.flags() & (STATIC | FINAL)) !=
(STATIC | FINAL))
log.warning(TreeInfo.diagnosticPositionFor(svuid, tree), "improper.SVUID", c);
// check that it is long
else if (svuid.type.tag != TypeTags.LONG)
log.warning(TreeInfo.diagnosticPositionFor(svuid, tree), "long.SVUID", c);
// check constant
else if (svuid.getConstValue() == null)
log.warning(TreeInfo.diagnosticPositionFor(svuid, tree), "constant.SVUID", c);
}
private Type capture(Type type) {
DEBUG.P(this,"capture(1)");
//return types.capture(type);
Type typeCapture = types.capture(type);
DEBUG.P("type ="+type);
DEBUG.P("typeCapture="+typeCapture);
DEBUG.P(0,this,"capture(1)");
return typeCapture;
}
}