jdk

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/*
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 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "cds/cdsConfig.hpp"
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#include "cds/serializeClosure.hpp"
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#include "classfile/symbolTable.hpp"
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#include "classfile/vmSymbols.hpp"
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#include "compiler/compilerDirectives.hpp"
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#include "jvm.h"
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#include "memory/allocation.inline.hpp"
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#include "memory/oopFactory.hpp"
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#include "memory/metaspaceClosure.hpp"
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#include "oops/oop.inline.hpp"
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#include "runtime/handles.inline.hpp"
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#include "runtime/signature.hpp"
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#include "utilities/xmlstream.hpp"
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Symbol* vmSymbols::_type_signatures[T_VOID+1] = { nullptr /*, nullptr...*/ };
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inline int compare_symbol(const Symbol* a, const Symbol* b) {
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  if (a == b)  return 0;
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  // follow the natural address order:
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  return (address)a > (address)b ? +1 : -1;
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}
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static vmSymbolID vm_symbol_index[vmSymbols::number_of_symbols()];
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extern "C" {
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  static int compare_vmsymbol_sid(const void* void_a, const void* void_b) {
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    const Symbol* a = Symbol::vm_symbol_at(*((vmSymbolID*) void_a));
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    const Symbol* b = Symbol::vm_symbol_at(*((vmSymbolID*) void_b));
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    return compare_symbol(a, b);
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  }
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}
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#ifdef ASSERT
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#define VM_SYMBOL_ENUM_NAME_BODY(name, string) #name "\0"
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static const char* vm_symbol_enum_names =
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  VM_SYMBOLS_DO(VM_SYMBOL_ENUM_NAME_BODY, VM_ALIAS_IGNORE)
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  "\0";
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static const char* vm_symbol_enum_name(vmSymbolID sid) {
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  const char* string = &vm_symbol_enum_names[0];
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  int skip = vmSymbols::as_int(sid) - vmSymbols::as_int(vmSymbolID::FIRST_SID);
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  for (; skip != 0; skip--) {
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    size_t skiplen = strlen(string);
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    if (skiplen == 0)  return "<unknown>";  // overflow
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    string += skiplen+1;
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  }
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  return string;
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}
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#endif //ASSERT
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// Put all the VM symbol strings in one place.
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// Makes for a more compact libjvm.
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#define VM_SYMBOL_BODY(name, string) string "\0"
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static const char* vm_symbol_bodies = VM_SYMBOLS_DO(VM_SYMBOL_BODY, VM_ALIAS_IGNORE);
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void vmSymbols::initialize() {
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  assert(SID_LIMIT <= (1<<log2_SID_LIMIT), "must fit in this bitfield");
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  assert(SID_LIMIT*5 > (1<<log2_SID_LIMIT), "make the bitfield smaller, please");
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  assert(vmIntrinsics::FLAG_LIMIT <= (1 << vmIntrinsics::log2_FLAG_LIMIT), "must fit in this bitfield");
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  if (!CDSConfig::is_using_archive()) {
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    const char* string = &vm_symbol_bodies[0];
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    for (auto index : EnumRange<vmSymbolID>{}) {
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      Symbol* sym = SymbolTable::new_permanent_symbol(string);
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      Symbol::_vm_symbols[as_int(index)] = sym;
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      string += strlen(string); // skip string body
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      string += 1;              // skip trailing null
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    }
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    _type_signatures[T_BYTE]    = byte_signature();
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    _type_signatures[T_CHAR]    = char_signature();
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    _type_signatures[T_DOUBLE]  = double_signature();
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    _type_signatures[T_FLOAT]   = float_signature();
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    _type_signatures[T_INT]     = int_signature();
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    _type_signatures[T_LONG]    = long_signature();
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    _type_signatures[T_SHORT]   = short_signature();
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    _type_signatures[T_BOOLEAN] = bool_signature();
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    _type_signatures[T_VOID]    = void_signature();
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#ifdef ASSERT
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    for (int i = (int)T_BOOLEAN; i < (int)T_VOID+1; i++) {
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      Symbol* s = _type_signatures[i];
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      if (s == nullptr)  continue;
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      SignatureStream ss(s, false);
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      assert(ss.type() == i, "matching signature");
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      assert(!ss.is_reference(), "no single-char signature for T_OBJECT, etc.");
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    }
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#endif
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  }
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#ifdef ASSERT
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  // Check for duplicates:
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  for (auto i1 : EnumRange<vmSymbolID>{}) {
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    Symbol* sym = symbol_at(i1);
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    for (auto i2 : EnumRange<vmSymbolID>{vmSymbolID::FIRST_SID, i1}) {
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      if (i2 != i1 && symbol_at(i2) == sym) {
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        tty->print("*** Duplicate VM symbol SIDs %s(%d) and %s(%d): \"",
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                   vm_symbol_enum_name(i2), as_int(i2),
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                   vm_symbol_enum_name(i1), as_int(i1));
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        sym->print_symbol_on(tty);
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        tty->print_cr("\"");
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      }
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    }
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  }
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#endif //ASSERT
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  // Create an index for find_id:
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  {
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    for (auto index : EnumRange<vmSymbolID>{}) {
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      vm_symbol_index[as_int(index)] = index;
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    }
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    int num_sids = SID_LIMIT-FIRST_SID;
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    qsort(&vm_symbol_index[FIRST_SID], num_sids, sizeof(vm_symbol_index[0]),
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          compare_vmsymbol_sid);
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  }
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#ifdef ASSERT
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  {
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    // Spot-check correspondence between strings, symbols, and enums:
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    assert(Symbol::_vm_symbols[NO_SID] == nullptr, "must be");
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    const char* str = "java/lang/Object";
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    TempNewSymbol jlo = SymbolTable::new_permanent_symbol(str);
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    assert(strncmp(str, (char*)jlo->base(), jlo->utf8_length()) == 0, "");
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    assert(jlo == java_lang_Object(), "");
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    vmSymbolID sid = VM_SYMBOL_ENUM_NAME(java_lang_Object);
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    assert(find_sid(jlo) == sid, "");
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    assert(symbol_at(sid) == jlo, "");
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    // Make sure find_sid produces the right answer in each case.
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    for (auto index : EnumRange<vmSymbolID>{}) {
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      Symbol* sym = symbol_at(index);
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      sid = find_sid(sym);
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      assert(sid == index, "symbol index works");
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      // Note:  If there are duplicates, this assert will fail.
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      // A "Duplicate VM symbol" message will have already been printed.
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    }
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    // The string "format" happens (at the moment) not to be a vmSymbol,
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    // though it is a method name in java.lang.String.
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    str = "format";
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    TempNewSymbol fmt = SymbolTable::new_permanent_symbol(str);
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    sid = find_sid(fmt);
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    assert(sid == vmSymbolID::NO_SID, "symbol index works (negative test)");
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  }
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#endif
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}
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#ifndef PRODUCT
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const char* vmSymbols::name_for(vmSymbolID sid) {
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  if (sid == vmSymbolID::NO_SID)
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    return "NO_SID";
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  const char* string = &vm_symbol_bodies[0];
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  for (auto index : EnumRange<vmSymbolID>{}) {
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    if (index == sid)
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      return string;
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    string += strlen(string); // skip string body
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    string += 1;              // skip trailing null
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  }
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  return "BAD_SID";
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}
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#endif
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void vmSymbols::symbols_do(SymbolClosure* f) {
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  for (auto index : EnumRange<vmSymbolID>{}) {
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    f->do_symbol(&Symbol::_vm_symbols[as_int(index)]);
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  }
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  for (int i = 0; i < T_VOID+1; i++) {
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    f->do_symbol(&_type_signatures[i]);
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  }
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}
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void vmSymbols::metaspace_pointers_do(MetaspaceClosure *closure) {
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  for (auto index : EnumRange<vmSymbolID>{}) {
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    closure->push(&Symbol::_vm_symbols[as_int(index)]);
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  }
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  for (int i = 0; i < T_VOID+1; i++) {
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    closure->push(&_type_signatures[i]);
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  }
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}
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void vmSymbols::serialize(SerializeClosure* soc) {
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  soc->do_ptrs((void**)&Symbol::_vm_symbols[FIRST_SID],
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                 (SID_LIMIT - FIRST_SID) * sizeof(Symbol::_vm_symbols[0]));
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  soc->do_ptrs((void**)_type_signatures, sizeof(_type_signatures));
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}
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#ifndef PRODUCT
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static uint find_sid_calls, find_sid_probes;
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// (Typical counts are calls=7000 and probes=17000.)
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#endif
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vmSymbolID vmSymbols::find_sid(const Symbol* symbol) {
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  static int mid_hint = FIRST_SID+1;
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  // Handle the majority of misses by a bounds check.
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  // Then, use a binary search over the index.
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  // Expected trip count is less than log2_SID_LIMIT, about eight.
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  // This is slow but acceptable, given that calls are not
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  // dynamically common.  (Method*::intrinsic_id has a cache.)
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  NOT_PRODUCT(find_sid_calls++);
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  int min = FIRST_SID, max = SID_LIMIT - 1;
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  vmSymbolID sid = vmSymbolID::NO_SID, sid1;
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  int cmp1;
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  sid1 = vm_symbol_index[min];
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  cmp1 = compare_symbol(symbol, Symbol::vm_symbol_at(sid1));
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  if (cmp1 <= 0) {              // before the first
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    if (cmp1 == 0)  sid = sid1;
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  } else {
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    sid1 = vm_symbol_index[max];
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    cmp1 = compare_symbol(symbol, symbol_at(sid1));
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    if (cmp1 >= 0) {            // after the last
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      if (cmp1 == 0)  sid = sid1;
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    } else {
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      // After checking the extremes, do a binary search.
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      ++min; --max;             // endpoints are done
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      int mid = mid_hint;       // start at previous success
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      while (max >= min) {
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        assert(mid >= min && mid <= max, "");
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        NOT_PRODUCT(find_sid_probes++);
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        sid1 = vm_symbol_index[mid];
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        cmp1 = compare_symbol(symbol, symbol_at(sid1));
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        if (cmp1 == 0) {
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          mid_hint = mid;
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          sid = sid1;
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          break;
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        }
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        if (cmp1 < 0)
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          max = mid - 1;        // symbol < symbol_at(sid)
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        else
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          min = mid + 1;
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        // Pick a new probe point:
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        mid = (max + min) / 2;
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      }
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    }
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  }
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#ifdef ASSERT
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  if (sid == vmSymbolID::NO_SID) {
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    return sid;
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  }
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  // Perform the exhaustive self-check the first 1000 calls,
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  // and every 100 calls thereafter.
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  static int find_sid_check_count = -2000;
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  if ((uint)++find_sid_check_count > (uint)100) {
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    if (find_sid_check_count > 0)  find_sid_check_count = 0;
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    // Make sure this is the right answer, using linear search.
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    // (We have already proven that there are no duplicates in the list.)
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    vmSymbolID sid2 = vmSymbolID::NO_SID;
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    for (auto index : EnumRange<vmSymbolID>{}) {
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      Symbol* sym2 = symbol_at(index);
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      if (sym2 == symbol) {
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        sid2 = index;
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        break;
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      }
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    }
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    // Unless it's a duplicate, assert that the sids are the same.
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    if (Symbol::_vm_symbols[as_int(sid)] != Symbol::_vm_symbols[as_int(sid2)]) {
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      assert(sid == sid2, "binary same as linear search");
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    }
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  }
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#endif //ASSERT
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  return sid;
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}
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vmSymbolID vmSymbols::find_sid(const char* symbol_name) {
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  Symbol* symbol = SymbolTable::probe(symbol_name, (int) strlen(symbol_name));
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  if (symbol == nullptr)  return vmSymbolID::NO_SID;
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  return find_sid(symbol);
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}
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