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8175883: bytecode generated for the enhanced for loop may block memory garbage collecting

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Reviewed-by: mcimadamore
This commit is contained in:
Vicente Romero 2017-11-20 17:07:21 -05:00
parent cffac90ef9
commit eeb940463b
2 changed files with 27 additions and 9 deletions
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34
src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Lower.java
View File

@ -3226,7 +3226,7 @@ public class Lower extends TreeTranslator {
JCVariableDecl indexdef = make.VarDef(index, make.Literal(INT, 0));
indexdef.init.type = indexdef.type = syms.intType.constType(0);
List<JCStatement> loopinit = List.of(arraycachedef, lencachedef, indexdef);
List<JCStatement> loopinit = List.of(lencachedef, indexdef);
JCBinary cond = makeBinary(LT, make.Ident(index), make.Ident(lencache));
JCExpressionStatement step = make.Exec(makeUnary(PREINC, make.Ident(index)));
@ -3236,18 +3236,27 @@ public class Lower extends TreeTranslator {
make.Ident(index)).setType(elemtype);
JCVariableDecl loopvardef = (JCVariableDecl)make.VarDef(tree.var.mods,
tree.var.name,
tree.var.vartype,
loopvarinit).setType(tree.var.type);
tree.var.vartype, null).setType(tree.var.type);
loopvardef.sym = tree.var.sym;
JCBlock body = make.
Block(0, List.of(loopvardef, tree.body));
JCStatement loopVarAssign = make.Assignment(tree.var.sym, loopvarinit);
JCBlock body = make.
Block(0, List.of(loopVarAssign, tree.body));
arraycachedef = translate(arraycachedef);
result = translate(make.
ForLoop(loopinit,
cond,
List.of(step),
body));
patchTargets(body, tree, result);
JCStatement nullAssignToArr = make.Assignment(arraycache, make.Literal(BOT, null).setType(syms.botType));
JCStatement nullAssignToLoopVar = tree.var.type.isPrimitive() ?
null :
make.Assignment(tree.var.sym, make.Literal(BOT, null).setType(syms.botType));
result = nullAssignToLoopVar == null ?
make.Block(0, List.of(arraycachedef, loopvardef, (JCStatement)result, nullAssignToArr)):
make.Block(0, List.of(arraycachedef, loopvardef, (JCStatement)result, nullAssignToArr, nullAssignToLoopVar));
}
/** Patch up break and continue targets. */
private void patchTargets(JCTree body, final JCTree src, final JCTree dest) {
@ -3322,16 +3331,25 @@ public class Lower extends TreeTranslator {
JCVariableDecl indexDef = (JCVariableDecl)make.VarDef(tree.var.mods,
tree.var.name,
tree.var.vartype,
vardefinit).setType(tree.var.type);
null).setType(tree.var.type);
indexDef.sym = tree.var.sym;
JCBlock body = make.Block(0, List.of(indexDef, tree.body));
JCStatement loopVarAssign = make.Assignment(tree.var.sym, vardefinit);
JCBlock body = make.Block(0, List.of(loopVarAssign, tree.body));
body.endpos = TreeInfo.endPos(tree.body);
init = translate(init);
result = translate(make.
ForLoop(List.of(init),
ForLoop(List.nil(),
cond,
List.nil(),
body));
patchTargets(body, tree, result);
JCStatement nullAssignToIterator = make.Assignment(itvar, make.Literal(BOT, null).setType(syms.botType));
JCStatement nullAssignToLoopVar = tree.var.type.isPrimitive() ?
null :
make.Assignment(tree.var.sym, make.Literal(BOT, null).setType(syms.botType));
result = nullAssignToLoopVar == null ?
make.Block(0, List.of(init, indexDef, (JCStatement)result, nullAssignToIterator)):
make.Block(0, List.of(init, indexDef, (JCStatement)result, nullAssignToIterator, nullAssignToLoopVar));
}
public void visitVarDef(JCVariableDecl tree) {

2
test/langtools/tools/javac/flow/tests/TestCaseForEach.java
View File

@ -3,7 +3,7 @@
public class TestCaseForEach {
@AliveRange(varName="o", bytecodeStart=25, bytecodeLength=11)
@AliveRange(varName="o", bytecodeStart=39, bytecodeLength=1)
@AliveRange(varName="o", bytecodeStart=44, bytecodeLength=1)
void m(String[] args) {
Object o;
for (String s : args) {