JVM的方法执行引擎模板表

TemplateInterpreter::initialize() templateInterpreter.cpp
interpreter_init() interpreter.cpp
init_globals() init.cpp
Threads::create_vm() thread.cpp
JNI_CreateJavaVM() jni.cpp
InitializeJVM() java.c
JavaMain() java.c
start_thread() pthread_create.c

源代码位置：/src/share/vm/interpreter/templateInterpreter.cpp

void TemplateInterpreter::initialize() {
if (_code != NULL)
return;

// 抽象解释器AbstractInterpreter的初始化，AbstractInterpreter是基于汇编模型的解释器的共同基类，
// 定义了解释器和解释器生成器的抽象接口
AbstractInterpreter::initialize();

// 模板表TemplateTable的初始化，模板表TemplateTable保存了各个字节码的模板
TemplateTable::initialize();

// generate interpreter
{
ResourceMark rm;
int code_size = InterpreterCodeSize;
// CodeCache的Stub队列StubQueue的初始化
_code = new StubQueue(new InterpreterCodeletInterface, code_size, NULL,"Interpreter");
// 实例化模板解释器生成器对象TemplateInterpreterGenerator
InterpreterGenerator g(_code);
}

// initialize dispatch table
_active_table = _normal_table;
}

InterpreterGenerator g(_code);

TemplateTable::initialize();

void TemplateTable::initialize() {
if (_is_initialized) return;
_bs = Universe::heap()->barrier_set();
// For better readability
const char _ = ‘ ‘;
const int ____ = 0;
const int ubcp = 1 < const int disp = 1 < const int clvm = 1 < const int iswd = 1 < // interpr. templates
// Java spec bytecodes ubcp|disp|clvm|iswd in out generator argument
def(Bytecodes::_nop , ____|____|____|____, vtos, vtos, nop , _ );
def(Bytecodes::_aconst_null , ____|____|____|____, vtos, atos, aconst_null , _ );
def(Bytecodes::_iconst_m1 , ____|____|____|____, vtos, itos, iconst , -1 );
def(Bytecodes::_iconst_0 , ____|____|____|____, vtos, itos, iconst , 0 );
// ...
def(Bytecodes::_tableswitch , ubcp|disp|____|____, itos, vtos, tableswitch , _ );
def(Bytecodes::_lookupswitch , ubcp|disp|____|____, itos, itos, lookupswitch , _ );
def(Bytecodes::_ireturn , ____|disp|clvm|____, itos, itos, _return , itos );
def(Bytecodes::_lreturn , ____|disp|clvm|____, ltos, ltos, _return , ltos );
def(Bytecodes::_freturn , ____|disp|clvm|____, ftos, ftos, _return , ftos );
def(Bytecodes::_dreturn , ____|disp|clvm|____, dtos, dtos, _return , dtos );
def(Bytecodes::_areturn , ____|disp|clvm|____, atos, atos, _return , atos );
def(Bytecodes::_return , ____|disp|clvm|____, vtos, vtos, _return , vtos );
def(Bytecodes::_getstatic , ubcp|____|clvm|____, vtos, vtos, getstatic , f1_byte );
def(Bytecodes::_putstatic , ubcp|____|clvm|____, vtos, vtos, putstatic , f2_byte );
def(Bytecodes::_getfield , ubcp|____|clvm|____, vtos, vtos, getfield , f1_byte );
def(Bytecodes::_putfield , ubcp|____|clvm|____, vtos, vtos, putfield , f2_byte );
def(Bytecodes::_invokevirtual , ubcp|disp|clvm|____, vtos, vtos, invokevirtual , f2_byte );
def(Bytecodes::_invokespecial , ubcp|disp|clvm|____, vtos, vtos, invokespecial , f1_byte );
def(Bytecodes::_invokestatic , ubcp|disp|clvm|____, vtos, vtos, invokestatic , f1_byte );
def(Bytecodes::_invokeinterface , ubcp|disp|clvm|____, vtos, vtos, invokeinterface , f1_byte );
def(Bytecodes::_invokedynamic , ubcp|disp|clvm|____, vtos, vtos, invokedynamic , f1_byte );
def(Bytecodes::_new , ubcp|____|clvm|____, vtos, atos, _new , _ );
def(Bytecodes::_newarray , ubcp|____|clvm|____, itos, atos, newarray , _ );
def(Bytecodes::_anewarray , ubcp|____|clvm|____, itos, atos, anewarray , _ );
def(Bytecodes::_arraylength , ____|____|____|____, atos, itos, arraylength , _ );
def(Bytecodes::_athrow , ____|disp|____|____, atos, vtos, athrow , _ );
def(Bytecodes::_checkcast , ubcp|____|clvm|____, atos, atos, checkcast , _ );
def(Bytecodes::_instanceof , ubcp|____|clvm|____, atos, itos, instanceof , _ );
def(Bytecodes::_monitorenter , ____|disp|clvm|____, atos, vtos, monitorenter , _ );
def(Bytecodes::_monitorexit , ____|____|clvm|____, atos, vtos, monitorexit , _ );
def(Bytecodes::_wide , ubcp|disp|____|____, vtos, vtos, wide , _ );
def(Bytecodes::_multianewarray , ubcp|____|clvm|____, vtos, atos, multianewarray , _ );
def(Bytecodes::_ifnull , ubcp|____|clvm|____, atos, vtos, if_nullcmp , equal );
def(Bytecodes::_ifnonnull , ubcp|____|clvm|____, atos, vtos, if_nullcmp , not_equal );
def(Bytecodes::_goto_w , ubcp|____|clvm|____, vtos, vtos, goto_w , _ );
def(Bytecodes::_jsr_w , ubcp|____|____|____, vtos, vtos, jsr_w , _ );
// wide Java spec bytecodes
def(Bytecodes::_iload , ubcp|____|____|iswd, vtos, itos, wide_iload , _ );
def(Bytecodes::_lload , ubcp|____|____|iswd, vtos, ltos, wide_lload , _ );
// ...
// JVM bytecodes
def(Bytecodes::_fast_agetfield , ubcp|____|____|____, atos, atos, fast_accessfield , atos );
def(Bytecodes::_fast_bgetfield , ubcp|____|____|____, atos, itos, fast_accessfield , itos );
def(Bytecodes::_fast_cgetfield , ubcp|____|____|____, atos, itos, fast_accessfield , itos );
def(Bytecodes::_fast_dgetfield , ubcp|____|____|____, atos, dtos, fast_accessfield , dtos );
def(Bytecodes::_fast_fgetfield , ubcp|____|____|____, atos, ftos, fast_accessfield , ftos );
def(Bytecodes::_fast_igetfield , ubcp|____|____|____, atos, itos, fast_accessfield , itos );
def(Bytecodes::_fast_lgetfield , ubcp|____|____|____, atos, ltos, fast_accessfield , ltos );
def(Bytecodes::_fast_sgetfield , ubcp|____|____|____, atos, itos, fast_accessfield , itos );
def(Bytecodes::_fast_aputfield , ubcp|____|____|____, atos, vtos, fast_storefield , atos );
def(Bytecodes::_fast_bputfield , ubcp|____|____|____, itos, vtos, fast_storefield , itos );
def(Bytecodes::_fast_cputfield , ubcp|____|____|____, itos, vtos, fast_storefield , itos );
def(Bytecodes::_fast_dputfield , ubcp|____|____|____, dtos, vtos, fast_storefield , dtos );
def(Bytecodes::_fast_fputfield , ubcp|____|____|____, ftos, vtos, fast_storefield , ftos );
def(Bytecodes::_fast_iputfield , ubcp|____|____|____, itos, vtos, fast_storefield , itos );
def(Bytecodes::_fast_lputfield , ubcp|____|____|____, ltos, vtos, fast_storefield , ltos );
def(Bytecodes::_fast_sputfield , ubcp|____|____|____, itos, vtos, fast_storefield , itos );
def(Bytecodes::_fast_aload_0 , ____|____|____|____, vtos, atos, aload , 0 );
def(Bytecodes::_fast_iaccess_0 , ubcp|____|____|____, vtos, itos, fast_xaccess , itos );
def(Bytecodes::_fast_aaccess_0 , ubcp|____|____|____, vtos, atos, fast_xaccess , atos );
def(Bytecodes::_fast_faccess_0 , ubcp|____|____|____, vtos, ftos, fast_xaccess , ftos );
def(Bytecodes::_fast_iload , ubcp|____|____|____, vtos, itos, fast_iload , _ );
def(Bytecodes::_fast_iload2 , ubcp|____|____|____, vtos, itos, fast_iload2 , _ );
def(Bytecodes::_fast_icaload , ubcp|____|____|____, vtos, itos, fast_icaload , _ );
def(Bytecodes::_fast_invokevfinal , ubcp|disp|clvm|____, vtos, vtos, fast_invokevfinal , f2_byte );
def(Bytecodes::_fast_linearswitch , ubcp|disp|____|____, itos, vtos, fast_linearswitch , _ );
def(Bytecodes::_fast_binaryswitch , ubcp|disp|____|____, itos, vtos, fast_binaryswitch , _ );
def(Bytecodes::_fast_aldc , ubcp|____|clvm|____, vtos, atos, fast_aldc , false );
def(Bytecodes::_fast_aldc_w , ubcp|____|clvm|____, vtos, atos, fast_aldc , true );
def(Bytecodes::_return_register_finalizer , ____|disp|clvm|____, vtos, vtos, _return , vtos );
def(Bytecodes::_invokehandle , ubcp|disp|clvm|____, vtos, vtos, invokehandle , f1_byte );
def(Bytecodes::_shouldnotreachhere , ____|____|____|____, vtos, vtos, shouldnotreachhere , _ );
// platform specific bytecodes
pd_initialize();
_is_initialized = true;
}

void TemplateTable::def(
Bytecodes::Code code, // 字节码指令
int flags, // 标志位
TosState in, // 模板执行前TosState
TosState out, // 模板执行后TosState
void (*gen)(), // 模板生成器，是模板的核心组件
char filler
) {
assert(filler == ‘ ‘, "just checkin‘");
def(code, flags, in, out, (Template::generator)gen, 0); // 调用下面的def()函数
}
void TemplateTable::def(
Bytecodes::Code code, // 字节码指令
int flags, // 标志位
TosState in, // 模板执行前TosState
TosState out, // 模板执行后TosState
void (*gen)(int arg), // 模板生成器，是模板的核心组件
int arg
) {
// should factor out these constants
const int ubcp = 1 < const int disp = 1 < const int clvm = 1 < const int iswd = 1 < // determine which table to use
bool is_wide = (flags & iswd) != 0;
// make sure that wide instructions have a vtos entry point
// (since they are executed extremely rarely, it doesn‘t pay out to have an
// extra set of 5 dispatch tables for the wide instructions - for simplicity
// they all go with one table)
assert(in == vtos || !is_wide, "wide instructions have vtos entry point only");
Template* t = is_wide ? template_for_wide(code) : template_for(code);
// setup entry
t->initialize(flags, in, out, gen, arg); // 调用模板表t的initialize()方法初始化模板表
assert(t->bytecode() == code, "just checkin‘");
}

源代码位置：hotspot/src/share/vm/interpreter/templateTable.hpp
// A Template describes the properties of a code template for a given bytecode
// and provides a generator to generate the code template.
class Template VALUE_OBJ_CLASS_SPEC {
private:
enum Flags {
// 字节码指令指的是该字节码的操作数是否存在于字节码里面
uses_bcp_bit, // set if template needs the bcp pointing to bytecode
does_dispatch_bit,// set if template dispatches on its own
calls_vm_bit, // set if template calls the vm
wide_bit // set if template belongs to a wide instruction
};
typedef void (*generator)(int arg);
int _flags; // describes interpreter template properties (bcp unknown)
TosState _tos_in; // tos cache state before template execution
TosState _tos_out; // tos cache state after template execution
generator _gen; // template code generator
int _arg; // argument for template code generator
...
// Templates
static Template* template_for(Bytecodes::Code code) {
Bytecodes::check(code);
return &_template_table[code];
}
static Template* template_for_wide(Bytecodes::Code code) {
Bytecodes::wide_check(code);
return &_template_table_wide[code];
}
};

static Template _template_table [Bytecodes::number_of_codes];
static Template _template_table_wide[Bytecodes::number_of_codes];

def(
Bytecodes::_iinc, // 字节码指令
ubcp|____|clvm|____, // 标志
vtos, // 模板执行前的TosState
vtos, // 模板执行后的TosState
iinc , // 模板生成器，是一个iinc()函数的指针
_ // 不需要模板生成器参数
);　

源代码位置：/hotspot/src/cpu/x86/vm/templateTable_x86_64.cpp
void TemplateTable::iinc() {
transition(vtos, vtos);
__ load_signed_byte(rdx, at_bcp(2)); // get constant
locals_index(rbx);
__ addl(iaddress(rbx), rdx);
}

iinc
index
const

// %r13存储的是指向字节码的指针，偏移2字节后取出const存储到%edx
0x00007fffe101a210: movsbl 0x2(%r13),%edx
// 取出index存储到%ebx
0x00007fffe101a215: movzbl 0x1(%r13),%ebx
0x00007fffe101a21a: neg %rbx
// %r14指向本地变量表的首地址，将%edx加到%r14+%rbx*8指向的内存所存储的值上
// 之所以要对%rbx执行neg进行符号反转，是因为在Linux内核的操作系统上，栈是向低地址方向生长的
0x00007fffe101a21d: add %edx,(%r14,%rbx,8)

void Template::initialize(int flags, TosState tos_in, TosState tos_out, generator gen, int arg) {
_flags = flags;
_tos_in = tos_in;
_tos_out = tos_out;
_gen = gen;
_arg = arg;
}