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8076758: new StringBuilder().append(String).toString() should be recognized by OptimizeStringConcat

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Reviewed-by: kvn, thartmann
This commit is contained in:
Aleksey Shipilev 2015-09-01 12:57:41 +03:00
parent 7b6480cfa4
commit e3007b79ad
1 changed files with 48 additions and 41 deletions
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89
hotspot/src/share/vm/opto/stringopts.cpp
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@ -1576,51 +1576,58 @@ void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
Node* result; Node* result;
if (!kit.stopped()) { if (!kit.stopped()) {
// length now contains the number of characters needed for the
// char[] so create a new AllocateArray for the char[]
Node* char_array = NULL; Node* char_array = NULL;
{ if (sc->num_arguments() == 1 &&
PreserveReexecuteState preexecs(&kit); (sc->mode(0) == StringConcat::StringMode ||
// The original jvms is for an allocation of either a String or sc->mode(0) == StringConcat::StringNullCheckMode)) {
// StringBuffer so no stack adjustment is necessary for proper // Handle the case when there is only a single String argument.
// reexecution. If we deoptimize in the slow path the bytecode // In this case, we can just pull the value from the String itself.
// will be reexecuted and the char[] allocation will be thrown away. char_array = kit.load_String_value(kit.control(), sc->argument(0));
kit.jvms()->set_should_reexecute(true); } else {
char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))), // length now contains the number of characters needed for the
length, 1); // char[] so create a new AllocateArray for the char[]
} {
PreserveReexecuteState preexecs(&kit);
// The original jvms is for an allocation of either a String or
// StringBuffer so no stack adjustment is necessary for proper
// reexecution. If we deoptimize in the slow path the bytecode
// will be reexecuted and the char[] allocation will be thrown away.
kit.jvms()->set_should_reexecute(true);
char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
length, 1);
}
// Mark the allocation so that zeroing is skipped since the code // Mark the allocation so that zeroing is skipped since the code
// below will overwrite the entire array // below will overwrite the entire array
AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn); AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
char_alloc->maybe_set_complete(_gvn); char_alloc->maybe_set_complete(_gvn);
// Now copy the string representations into the final char[] // Now copy the string representations into the final char[]
Node* start = __ intcon(0); Node* start = __ intcon(0);
for (int argi = 0; argi < sc->num_arguments(); argi++) { for (int argi = 0; argi < sc->num_arguments(); argi++) {
Node* arg = sc->argument(argi); Node* arg = sc->argument(argi);
switch (sc->mode(argi)) { switch (sc->mode(argi)) {
case StringConcat::IntMode: { case StringConcat::IntMode: {
Node* end = __ AddI(start, string_sizes->in(argi)); Node* end = __ AddI(start, string_sizes->in(argi));
// getChars words backwards so pass the ending point as well as the start // getChars words backwards so pass the ending point as well as the start
int_getChars(kit, arg, char_array, start, end); int_getChars(kit, arg, char_array, start, end);
start = end; start = end;
break; break;
}
case StringConcat::StringNullCheckMode:
case StringConcat::StringMode: {
start = copy_string(kit, arg, char_array, start);
break;
}
case StringConcat::CharMode: {
__ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
arg, T_CHAR, char_adr_idx, MemNode::unordered);
start = __ AddI(start, __ intcon(1));
break;
}
default:
ShouldNotReachHere();
} }
case StringConcat::StringNullCheckMode:
case StringConcat::StringMode: {
start = copy_string(kit, arg, char_array, start);
break;
}
case StringConcat::CharMode: {
__ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
arg, T_CHAR, char_adr_idx, MemNode::unordered);
start = __ AddI(start, __ intcon(1));
break;
}
default:
ShouldNotReachHere();
} }
} }