1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.nashorn.internal.codegen;
import static jdk.nashorn.internal.codegen.CompilerConstants.CALLEE;
import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE;
import jdk.nashorn.internal.ir.BinaryNode;
import jdk.nashorn.internal.ir.Block;
import jdk.nashorn.internal.ir.Expression;
import jdk.nashorn.internal.ir.ExpressionStatement;
import jdk.nashorn.internal.ir.ForNode;
import jdk.nashorn.internal.ir.FunctionNode;
import jdk.nashorn.internal.ir.FunctionNode.CompilationState;
import jdk.nashorn.internal.ir.LexicalContext;
import jdk.nashorn.internal.ir.Node;
import jdk.nashorn.internal.ir.Symbol;
import jdk.nashorn.internal.ir.TemporarySymbols;
import jdk.nashorn.internal.ir.UnaryNode;
import jdk.nashorn.internal.ir.visitor.NodeOperatorVisitor;
import jdk.nashorn.internal.parser.Token;
import jdk.nashorn.internal.parser.TokenType;
import jdk.nashorn.internal.runtime.DebugLogger;
/**
* Lower to more primitive operations. After lowering, an AST has symbols and
* types. Lowering may also add specialized versions of methods to the script if
* the optimizer is turned on.
*
* Any expression that requires temporary storage as part of computation will
* also be detected here and give a temporary symbol
*
* For any op that we process in FinalizeTypes it is an absolute guarantee
* that scope and slot information is correct. This enables e.g. AccessSpecialization
* and frame optimizations
*/
final class FinalizeTypes extends NodeOperatorVisitor<LexicalContext> {
private static final DebugLogger LOG = new DebugLogger("finalize");
private final TemporarySymbols temporarySymbols;
FinalizeTypes(final TemporarySymbols temporarySymbols) {
super(new LexicalContext());
this.temporarySymbols = temporarySymbols;
}
@Override
public Node leaveForNode(final ForNode forNode) {
if (forNode.isForIn()) {
return forNode;
}
final Expression init = forNode.getInit();
final Expression test = forNode.getTest();
final Expression modify = forNode.getModify();
assert test != null || forNode.hasGoto() : "forNode " + forNode + " needs goto and is missing it in " + lc.getCurrentFunction();
return forNode.
setInit(lc, init == null ? null : discard(init)).
setModify(lc, modify == null ? null : discard(modify));
}
@Override
public Node leaveCOMMALEFT(final BinaryNode binaryNode) {
assert binaryNode.getSymbol() != null;
return binaryNode.setRHS(discard(binaryNode.rhs()));
}
@Override
public Node leaveCOMMARIGHT(final BinaryNode binaryNode) {
assert binaryNode.getSymbol() != null;
return binaryNode.setLHS(discard(binaryNode.lhs()));
}
@Override
public boolean enterBlock(final Block block) {
updateSymbols(block);
return true;
}
@Override
public Node leaveExpressionStatement(final ExpressionStatement expressionStatement) {
temporarySymbols.reuse();
return expressionStatement.setExpression(discard(expressionStatement.getExpression()));
}
@Override
public boolean enterFunctionNode(final FunctionNode functionNode) {
if (functionNode.isLazy()) {
return false;
}
// If the function doesn't need a callee, we ensure its __callee__ symbol doesn't get a slot. We can't do
// this earlier, as access to scoped variables, self symbol, etc. in previous phases can all trigger the
// need for the callee.
if (!functionNode.needsCallee()) {
functionNode.compilerConstant(CALLEE).setNeedsSlot(false);
}
// Similar reasoning applies to __scope__ symbol: if the function doesn't need either parent scope and none of
// its blocks create a scope, we ensure it doesn't get a slot, but we can't determine whether it needs a scope
// earlier than this phase.
if (!(functionNode.hasScopeBlock() || functionNode.needsParentScope())) {
functionNode.compilerConstant(SCOPE).setNeedsSlot(false);
}
return true;
}
@Override
public Node leaveFunctionNode(final FunctionNode functionNode) {
return functionNode.setState(lc, CompilationState.FINALIZED);
}
private static void updateSymbolsLog(final FunctionNode functionNode, final Symbol symbol, final boolean loseSlot) {
if (LOG.isEnabled()) {
if (!symbol.isScope()) {
LOG.finest("updateSymbols: ", symbol, " => scope, because all vars in ", functionNode.getName(), " are in scope");
}
if (loseSlot && symbol.hasSlot()) {
LOG.finest("updateSymbols: ", symbol, " => no slot, because all vars in ", functionNode.getName(), " are in scope");
}
}
}
/**
* Called after a block or function node (subclass of block) is finished. Guarantees
* that scope and slot information is correct for every symbol
* @param block block for which to to finalize type info.
*/
private void updateSymbols(final Block block) {
if (!block.needsScope()) {
return; // nothing to do
}
final FunctionNode functionNode = lc.getFunction(block);
final boolean allVarsInScope = functionNode.allVarsInScope();
final boolean isVarArg = functionNode.isVarArg();
for (final Symbol symbol : block.getSymbols()) {
if (symbol.isInternal() || symbol.isThis() || symbol.isTemp()) {
continue;
}
if (symbol.isVar()) {
if (allVarsInScope || symbol.isScope()) {
updateSymbolsLog(functionNode, symbol, true);
Symbol.setSymbolIsScope(lc, symbol);
symbol.setNeedsSlot(false);
} else {
assert symbol.hasSlot() : symbol + " should have a slot only, no scope";
}
} else if (symbol.isParam() && (allVarsInScope || isVarArg || symbol.isScope())) {
updateSymbolsLog(functionNode, symbol, isVarArg);
Symbol.setSymbolIsScope(lc, symbol);
symbol.setNeedsSlot(!isVarArg);
}
}
}
private static Expression discard(final Expression node) {
if (node.getSymbol() != null) {
final UnaryNode discard = new UnaryNode(Token.recast(node.getToken(), TokenType.DISCARD), node);
//discard never has a symbol in the discard node - then it would be a nop
assert !node.isTerminal();
return discard;
}
// node has no result (symbol) so we can keep it the way it is
return node;
}
}
|
