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/*
* Copyright (c) 1997, 2021, 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.
*
* 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.
*
*/
#include "precompiled.hpp"
#include "classfile/symbolTable.hpp"
#include "classfile/vmSymbols.hpp"
#include "compiler/compilerDirectives.hpp"
#include "jvm.h"
#include "memory/allocation.inline.hpp"
#include "memory/oopFactory.hpp"
#include "memory/metaspaceClosure.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/signature.hpp"
#include "utilities/tribool.hpp"
#include "utilities/xmlstream.hpp"
Symbol* vmSymbols::_type_signatures[T_VOID+1] = { NULL /*, NULL...*/ };
inline int compare_symbol(const Symbol* a, const Symbol* b) {
if (a == b) return 0;
// follow the natural address order:
return (address)a > (address)b ? +1 : -1;
}
static vmSymbolID vm_symbol_index[vmSymbols::number_of_symbols()];
extern "C" {
static int compare_vmsymbol_sid(const void* void_a, const void* void_b) {
const Symbol* a = Symbol::vm_symbol_at(*((vmSymbolID*) void_a));
const Symbol* b = Symbol::vm_symbol_at(*((vmSymbolID*) void_b));
return compare_symbol(a, b);
}
}
#ifdef ASSERT
#define VM_SYMBOL_ENUM_NAME_BODY(name, string) #name "\0"
static const char* vm_symbol_enum_names =
VM_SYMBOLS_DO(VM_SYMBOL_ENUM_NAME_BODY, VM_ALIAS_IGNORE)
"\0";
static const char* vm_symbol_enum_name(vmSymbolID sid) {
const char* string = &vm_symbol_enum_names[0];
int skip = vmSymbols::as_int(sid) - vmSymbols::as_int(vmSymbolID::FIRST_SID);
for (; skip != 0; skip--) {
size_t skiplen = strlen(string);
if (skiplen == 0) return ""; // overflow
string += skiplen+1;
}
return string;
}
#endif //ASSERT
// Put all the VM symbol strings in one place.
// Makes for a more compact libjvm.
#define VM_SYMBOL_BODY(name, string) string "\0"
static const char* vm_symbol_bodies = VM_SYMBOLS_DO(VM_SYMBOL_BODY, VM_ALIAS_IGNORE);
void vmSymbols::initialize() {
assert(SID_LIMIT <= (1<<log2_SID_LIMIT), "must fit in this bitfield");
assert(SID_LIMIT*5 > (1<<log2_SID_LIMIT), "make the bitfield smaller, please");
assert(vmIntrinsics::FLAG_LIMIT <= (1 << vmIntrinsics::log2_FLAG_LIMIT), "must fit in this bitfield");
if (!UseSharedSpaces) {
const char* string = &vm_symbol_bodies[0];
for (auto index : EnumRange<vmSymbolID>{}) {
Symbol* sym = SymbolTable::new_permanent_symbol(string);
Symbol::_vm_symbols[as_int(index)] = sym;
string += strlen(string); // skip string body
string += 1; // skip trailing null
}
_type_signatures[T_BYTE] = byte_signature();
_type_signatures[T_CHAR] = char_signature();
_type_signatures[T_DOUBLE] = double_signature();
_type_signatures[T_FLOAT] = float_signature();
_type_signatures[T_INT] = int_signature();
_type_signatures[T_LONG] = long_signature();
_type_signatures[T_SHORT] = short_signature();
_type_signatures[T_BOOLEAN] = bool_signature();
_type_signatures[T_VOID] = void_signature();
#ifdef ASSERT
for (int i = (int)T_BOOLEAN; i < (int)T_VOID+1; i++) {
Symbol* s = _type_signatures[i];
if (s == NULL) continue;
SignatureStream ss(s, false);
assert(ss.type() == i, "matching signature");
assert(!ss.is_reference(), "no single-char signature for T_OBJECT, etc.");
}
#endif
}
#ifdef ASSERT
// Check for duplicates:
for (auto i1 : EnumRange<vmSymbolID>{}) {
Symbol* sym = symbol_at(i1);
for (auto i2 : EnumRange<vmSymbolID>{vmSymbolID::FIRST_SID, i1}) {
if (i2 != i1 && symbol_at(i2) == sym) {
tty->print("*** Duplicate VM symbol SIDs %s(%d) and %s(%d): \"",
vm_symbol_enum_name(i2), as_int(i2),
vm_symbol_enum_name(i1), as_int(i1));
sym->print_symbol_on(tty);
tty->print_cr("\"");
}
}
}
#endif //ASSERT
// Create an index for find_id:
{
for (auto index : EnumRange<vmSymbolID>{}) {
vm_symbol_index[as_int(index)] = index;
}
int num_sids = SID_LIMIT-FIRST_SID;
qsort(&vm_symbol_index[FIRST_SID], num_sids, sizeof(vm_symbol_index[0]),
compare_vmsymbol_sid);
}
#ifdef ASSERT
{
// Spot-check correspondence between strings, symbols, and enums:
assert(Symbol::_vm_symbols[NO_SID] == NULL, "must be");
const char* str = "java/lang/Object";
TempNewSymbol jlo = SymbolTable::new_permanent_symbol(str);
assert(strncmp(str, (char*)jlo->base(), jlo->utf8_length()) == 0, "");
assert(jlo == java_lang_Object(), "");
vmSymbolID sid = VM_SYMBOL_ENUM_NAME(java_lang_Object);
assert(find_sid(jlo) == sid, "");
assert(symbol_at(sid) == jlo, "");
// Make sure find_sid produces the right answer in each case.
for (auto index : EnumRange<vmSymbolID>{}) {
Symbol* sym = symbol_at(index);
sid = find_sid(sym);
assert(sid == index, "symbol index works");
// Note: If there are duplicates, this assert will fail.
// A "Duplicate VM symbol" message will have already been printed.
}
// The string "format" happens (at the moment) not to be a vmSymbol,
// though it is a method name in java.lang.String.
str = "format";
TempNewSymbol fmt = SymbolTable::new_permanent_symbol(str);
sid = find_sid(fmt);
assert(sid == vmSymbolID::NO_SID, "symbol index works (negative test)");
}
#endif
}
#ifndef PRODUCT
const char* vmSymbols::name_for(vmSymbolID sid) {
if (sid == vmSymbolID::NO_SID)
return "NO_SID";
const char* string = &vm_symbol_bodies[0];
for (auto index : EnumRange<vmSymbolID>{}) {
if (index == sid)
return string;
string += strlen(string); // skip string body
string += 1; // skip trailing null
}
return "BAD_SID";
}
#endif
void vmSymbols::symbols_do(SymbolClosure* f) {
for (auto index : EnumRange<vmSymbolID>{}) {
f->do_symbol(&Symbol::_vm_symbols[as_int(index)]);
}
for (int i = 0; i < T_VOID+1; i++) {
f->do_symbol(&_type_signatures[i]);
}
}
void vmSymbols::metaspace_pointers_do(MetaspaceClosure *closure) {
for (auto index : EnumRange<vmSymbolID>{}) {
closure->push(&Symbol::_vm_symbols[as_int(index)]);
}
for (int i = 0; i < T_VOID+1; i++) {
closure->push(&_type_signatures[i]);
}
}
void vmSymbols::serialize(SerializeClosure* soc) {
soc->do_region((u_char*)&Symbol::_vm_symbols[FIRST_SID],
(SID_LIMIT - FIRST_SID) * sizeof(Symbol::_vm_symbols[0]));
soc->do_region((u_char*)_type_signatures, sizeof(_type_signatures));
}
#ifndef PRODUCT
static int find_sid_calls, find_sid_probes;
// (Typical counts are calls=7000 and probes=17000.)
#endif
vmSymbolID vmSymbols::find_sid(const Symbol* symbol) {
static int mid_hint = FIRST_SID+1;
// Handle the majority of misses by a bounds check.
// Then, use a binary search over the index.
// Expected trip count is less than log2_SID_LIMIT, about eight.
// This is slow but acceptable, given that calls are not
// dynamically common. (Method*::intrinsic_id has a cache.)
NOT_PRODUCT(find_sid_calls++);
int min = FIRST_SID, max = SID_LIMIT - 1;
vmSymbolID sid = vmSymbolID::NO_SID, sid1;
int cmp1;
sid1 = vm_symbol_index[min];
cmp1 = compare_symbol(symbol, Symbol::vm_symbol_at(sid1));
if (cmp1 <= 0) { // before the first
if (cmp1 == 0) sid = sid1;
} else {
sid1 = vm_symbol_index[max];
cmp1 = compare_symbol(symbol, symbol_at(sid1));
if (cmp1 >= 0) { // after the last
if (cmp1 == 0) sid = sid1;
} else {
// After checking the extremes, do a binary search.
++min; --max; // endpoints are done
int mid = mid_hint; // start at previous success
while (max >= min) {
assert(mid >= min && mid <= max, "");
NOT_PRODUCT(find_sid_probes++);
sid1 = vm_symbol_index[mid];
cmp1 = compare_symbol(symbol, symbol_at(sid1));
if (cmp1 == 0) {
mid_hint = mid;
sid = sid1;
break;
}
if (cmp1 < 0)
max = mid - 1; // symbol < symbol_at(sid)
else
min = mid + 1;
// Pick a new probe point:
mid = (max + min) / 2;
}
}
}
#ifdef ASSERT
if (sid == vmSymbolID::NO_SID) {
return sid;
}
// Perform the exhaustive self-check the first 1000 calls,
// and every 100 calls thereafter.
static int find_sid_check_count = -2000;
if ((uint)++find_sid_check_count > (uint)100) {
if (find_sid_check_count > 0) find_sid_check_count = 0;
// Make sure this is the right answer, using linear search.
// (We have already proven that there are no duplicates in the list.)
vmSymbolID sid2 = vmSymbolID::NO_SID;
for (auto index : EnumRange<vmSymbolID>{}) {
Symbol* sym2 = symbol_at(index);
if (sym2 == symbol) {
sid2 = index;
break;
}
}
// Unless it's a duplicate, assert that the sids are the same.
if (Symbol::_vm_symbols[as_int(sid)] != Symbol::_vm_symbols[as_int(sid2)]) {
assert(sid == sid2, "binary same as linear search");
}
}
#endif //ASSERT
return sid;
}
vmSymbolID vmSymbols::find_sid(const char* symbol_name) {
Symbol* symbol = SymbolTable::probe(symbol_name, (int) strlen(symbol_name));
if (symbol == NULL) return vmSymbolID::NO_SID;
return find_sid(symbol);
}
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