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7009359: HS with -XX:+AggressiveOpts optimize new StringBuffer(null) so it does not throw NPE as expected

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Bailout StringConcat optimization if null is passed to StringBuffer constructor.

Reviewed-by: iveresov
This commit is contained in:
Vladimir Kozlov 2010-12-28 17:34:02 -08:00
parent 43280aa63e
commit 4286ac7947
2 changed files with 92 additions and 3 deletions
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43
hotspot/src/share/vm/opto/stringopts.cpp
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@ -59,7 +59,8 @@ class StringConcat : public ResourceObj {
enum {
StringMode,
IntMode,
CharMode
CharMode,
StringNullCheckMode
};
StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
@ -114,6 +115,9 @@ class StringConcat : public ResourceObj {
void push_string(Node* value) {
push(value, StringMode);
}
void push_string_null_check(Node* value) {
push(value, StringNullCheckMode);
}
void push_int(Node* value) {
push(value, IntMode);
}
@ -416,7 +420,19 @@ StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
if (sig == ciSymbol::string_void_signature()) {
// StringBuilder(String) so pick this up as the first argument
assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
sc->push_string(use->in(TypeFunc::Parms + 1));
const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
if (type == TypePtr::NULL_PTR) {
// StringBuilder(null) throws exception.
#ifndef PRODUCT
if (PrintOptimizeStringConcat) {
tty->print("giving up because StringBuilder(null) throws exception");
alloc->jvms()->dump_spec(tty); tty->cr();
}
#endif
return NULL;
}
// StringBuilder(str) argument needs null check.
sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
}
// The int variant takes an initial size for the backing
// array so just treat it like the void version.
@ -436,7 +452,7 @@ StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
#ifndef PRODUCT
if (PrintOptimizeStringConcat) {
tty->print("giving up because couldn't find constructor ");
alloc->jvms()->dump_spec(tty);
alloc->jvms()->dump_spec(tty); tty->cr();
}
#endif
break;
@ -1269,6 +1285,25 @@ void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
string_sizes->init_req(argi, string_size);
break;
}
case StringConcat::StringNullCheckMode: {
const Type* type = kit.gvn().type(arg);
assert(type != TypePtr::NULL_PTR, "missing check");
if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
// Null check with uncommont trap since
// StringBuilder(null) throws exception.
// Use special uncommon trap instead of
// calling normal do_null_check().
Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
overflow->add_req(__ IfFalse(iff));
Node* notnull = __ IfTrue(iff);
kit.set_control(notnull); // set control for the cast_not_null
arg = kit.cast_not_null(arg, false);
sc->set_argument(argi, arg);
}
assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
// Fallthrough to add string length.
}
case StringConcat::StringMode: {
const Type* type = kit.gvn().type(arg);
if (type == TypePtr::NULL_PTR) {
@ -1328,6 +1363,7 @@ void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
// Hook
PreserveJVMState pjvms(&kit);
kit.set_control(overflow);
C->record_for_igvn(overflow);
kit.uncommon_trap(Deoptimization::Reason_intrinsic,
Deoptimization::Action_make_not_entrant);
}
@ -1363,6 +1399,7 @@ void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
start = end;
break;
}
case StringConcat::StringNullCheckMode:
case StringConcat::StringMode: {
start = copy_string(kit, arg, char_array, start);
break;