これらは, C2 JIT Compiler 用のクラス. より具体的に言うと, 高レベル中間語の構築作業を容易化するための補助クラス.
GraphKit クラスやそのサブクラス (より具体的に言うと GraphKit クラスと LibraryCallKit クラス) 内で使用される補助クラス.
Ideal を構築する作業用の一時オブジェクト(StackObjクラス). 複雑な Ideal グラフ (if や loop 等を含むもの) を作りたい場合に, その構築を簡単にするメソッドを提供している.
((cite: hotspot/src/share/vm/opto/idealKit.hpp))
class IdealKit: public StackObj {
((cite: hotspot/src/share/vm/opto/idealKit.hpp))
//-----------------------------------------------------------------------------
//----------------------------IdealKit-----------------------------------------
// Set of utilities for creating control flow and scalar SSA data flow.
// Control:
// if_then(left, relop, right)
// else_ (optional)
// end_if
// loop(iv variable, initial, relop, limit)
// - sets iv to initial for first trip
// - exits when relation on limit is true
// - the values of initial and limit should be loop invariant
// - no increment, must be explicitly coded
// - final value of iv is available after end_loop (until dead())
// end_loop
// make_label(number of gotos)
// goto_(label)
// bind(label)
// Data:
// ConI(integer constant) - create an integer constant
// set(variable, value) - assignment
// value(variable) - reference value
// dead(variable) - variable's value is no longer live
// increment(variable, value) - increment variable by value
// simple operations: AddI, SubI, AndI, LShiftI, etc.
// Example:
// Node* limit = ??
// IdealVariable i(kit), j(kit);
// declarations_done();
// Node* exit = make_label(1); // 1 goto
// set(j, ConI(0));
// loop(i, ConI(0), BoolTest::lt, limit); {
// if_then(value(i), BoolTest::gt, ConI(5)) {
// set(j, ConI(1));
// goto_(exit); dead(i);
// } end_if();
// increment(i, ConI(1));
// } end_loop(); dead(i);
// bind(exit);
//
// See string_indexOf for a more complete example.
(使用時には IdealKit のコンストラクタに GraphKit オブジェクトを渡す. IdealKit のメソッドを呼び出すと内部で GraphKit のメソッドが呼び出される)
以下のように "__ loop()" や "__ if_then()" と書くだけで Ideal が構築できる.
((cite: hotspot/src/share/vm/opto/library_call.cpp))
IdealKit kit(this, false, true);
#define __ kit.
Node* zero = __ ConI(0);
Node* one = __ ConI(1);
Node* cache = __ ConI(cache_i);
Node* md2 = __ ConI(md2_i);
Node* lastChar = __ ConI(target_array->char_at(target_length - 1));
Node* targetCount = __ ConI(target_length);
Node* targetCountLess1 = __ ConI(target_length - 1);
Node* targetOffset = __ ConI(targetOffset_i);
Node* sourceEnd = __ SubI(__ AddI(sourceOffset, sourceCount), targetCountLess1);
IdealVariable rtn(kit), i(kit), j(kit); __ declarations_done();
Node* outer_loop = __ make_label(2 /* goto */);
Node* return_ = __ make_label(1);
__ set(rtn,__ ConI(-1));
__ loop(this, nargs, i, sourceOffset, BoolTest::lt, sourceEnd); {
Node* i2 = __ AddI(__ value(i), targetCountLess1);
// pin to prohibit loading of "next iteration" value which may SEGV (rare)
Node* src = load_array_element(__ ctrl(), source, i2, TypeAryPtr::CHARS);
__ if_then(src, BoolTest::eq, lastChar, unlikely); {
__ loop(this, nargs, j, zero, BoolTest::lt, targetCountLess1); {
Node* tpj = __ AddI(targetOffset, __ value(j));
Node* targ = load_array_element(no_ctrl, target, tpj, target_type);
Node* ipj = __ AddI(__ value(i), __ value(j));
Node* src2 = load_array_element(no_ctrl, source, ipj, TypeAryPtr::CHARS);
__ if_then(targ, BoolTest::ne, src2); {
__ if_then(__ AndI(cache, __ LShiftI(one, src2)), BoolTest::eq, zero); {
__ if_then(md2, BoolTest::lt, __ AddI(__ value(j), one)); {
__ increment(i, __ AddI(__ value(j), one));
__ goto_(outer_loop);
} __ end_if(); __ dead(j);
}__ end_if(); __ dead(j);
__ increment(i, md2);
__ goto_(outer_loop);
}__ end_if();
__ increment(j, one);
}__ end_loop(); __ dead(j);
__ set(rtn, __ SubI(__ value(i), sourceOffset)); __ dead(i);
__ goto_(return_);
}__ end_if();
__ if_then(__ AndI(cache, __ LShiftI(one, src)), BoolTest::eq, zero, likely); {
__ increment(i, targetCountLess1);
}__ end_if();
__ increment(i, one);
__ bind(outer_loop);
}__ end_loop(); __ dead(i);
__ bind(return_);
以下の箇所で(のみ)使用されている.
See: here for details
IdealKit クラス用の補助クラス(StackObjクラス).
IdealKit クラスによる Ideal 構築時に「変数」として利用できる補助クラス.
((cite: hotspot/src/share/vm/opto/idealKit.hpp))
// Variable definition for IdealKit
class IdealVariable: public StackObj {
IdealKit::set()/IdealKit::value() で値を設定／参照できる他, IdealKit::loop() の制御変数等としても利用できる.
((cite: hotspot/src/share/vm/opto/library_call.cpp))
IdealKit kit(this, false, true);
#define __ kit.
Node* zero = __ ConI(0);
Node* one = __ ConI(1);
Node* cache = __ ConI(cache_i);
Node* md2 = __ ConI(md2_i);
Node* lastChar = __ ConI(target_array->char_at(target_length - 1));
Node* targetCount = __ ConI(target_length);
Node* targetCountLess1 = __ ConI(target_length - 1);
Node* targetOffset = __ ConI(targetOffset_i);
Node* sourceEnd = __ SubI(__ AddI(sourceOffset, sourceCount), targetCountLess1);
IdealVariable rtn(kit), i(kit), j(kit); __ declarations_done();
Node* outer_loop = __ make_label(2 /* goto */);
Node* return_ = __ make_label(1);
__ set(rtn,__ ConI(-1));
__ loop(this, nargs, i, sourceOffset, BoolTest::lt, sourceEnd); {
Node* i2 = __ AddI(__ value(i), targetCountLess1);
// pin to prohibit loading of "next iteration" value which may SEGV (rare)
Node* src = load_array_element(__ ctrl(), source, i2, TypeAryPtr::CHARS);
__ if_then(src, BoolTest::eq, lastChar, unlikely); {
__ loop(this, nargs, j, zero, BoolTest::lt, targetCountLess1); {
Node* tpj = __ AddI(targetOffset, __ value(j));
Node* targ = load_array_element(no_ctrl, target, tpj, target_type);
Node* ipj = __ AddI(__ value(i), __ value(j));
Node* src2 = load_array_element(no_ctrl, source, ipj, TypeAryPtr::CHARS);
__ if_then(targ, BoolTest::ne, src2); {
__ if_then(__ AndI(cache, __ LShiftI(one, src2)), BoolTest::eq, zero); {
__ if_then(md2, BoolTest::lt, __ AddI(__ value(j), one)); {
__ increment(i, __ AddI(__ value(j), one));
__ goto_(outer_loop);
} __ end_if(); __ dead(j);
}__ end_if(); __ dead(j);
__ increment(i, md2);
__ goto_(outer_loop);
}__ end_if();
__ increment(j, one);
}__ end_loop(); __ dead(j);
__ set(rtn, __ SubI(__ value(i), sourceOffset)); __ dead(i);
__ goto_(return_);
}__ end_if();
__ if_then(__ AndI(cache, __ LShiftI(one, src)), BoolTest::eq, zero, likely); {
__ increment(i, targetCountLess1);
}__ end_if();
__ increment(i, one);
__ bind(outer_loop);
}__ end_loop(); __ dead(i);
__ bind(return_);
LibraryCallKit::string_indexOf() 内で(のみ)使用されている.
See: here for details
This document is available under the GNU GENERAL PUBLIC LICENSE Version 2.