0ee6ffb257
Graphite is now available under: MIT OR MPL-2.0 OR LGPL-2.1-or-later OR GPL-2.0-or-later We pick MIT which is the same as Godot's main license for simplicity. Remove define to skip deprecation warnings, upstream fixed those.
117 lines
4.1 KiB
C++
117 lines
4.1 KiB
C++
// SPDX-License-Identifier: MIT OR MPL-2.0 OR LGPL-2.1-or-later OR GPL-2.0-or-later
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// Copyright 2010, SIL International, All rights reserved.
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// This direct threaded interpreter implmentation for machine.h
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// Author: Tim Eves
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// Build either this interpreter or the call_machine implementation.
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// The direct threaded interpreter is relies upon a gcc feature called
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// labels-as-values so is only portable to compilers that support the
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// extension (gcc only as far as I know) however it should build on any
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// architecture gcc supports.
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// This is twice as fast as the call threaded model and is likely faster on
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// inorder processors with short pipelines and little branch prediction such
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// as the ARM and possibly Atom chips.
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#include <cassert>
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#include <cstring>
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#include "inc/Machine.h"
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#include "inc/Segment.h"
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#include "inc/Slot.h"
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#include "inc/Rule.h"
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#define STARTOP(name) name: {
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#define ENDOP }; goto *((sp - sb)/Machine::STACK_MAX ? &&end : *++ip);
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#define EXIT(status) { push(status); goto end; }
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#define do_(name) &&name
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using namespace graphite2;
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using namespace vm;
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namespace {
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// The GCC manual has this to say about labels as values:
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// The &&foo expressions for the same label might have different values
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// if the containing function is inlined or cloned. If a program relies
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// on them being always the same, __attribute__((__noinline__,__noclone__))
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// should be used to prevent inlining and cloning.
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//
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// is_return in Code.cpp relies on being able to do comparisons, so it needs
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// them to be always the same.
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//
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// The GCC manual further adds:
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// If &&foo is used in a static variable initializer, inlining and
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// cloning is forbidden.
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//
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// In this file, &&foo *is* used in a static variable initializer, and it's not
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// entirely clear whether this should prevent inlining of the function or not.
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// In practice, though, clang 7 can end up inlining the function with ThinLTO,
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// which breaks at least is_return. https://bugs.llvm.org/show_bug.cgi?id=39241
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// So all in all, we need at least the __noinline__ attribute. __noclone__
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// is not supported by clang.
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__attribute__((__noinline__))
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const void * direct_run(const bool get_table_mode,
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const instr * program,
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const byte * data,
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Machine::stack_t * stack,
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slotref * & __map,
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uint8 _dir,
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Machine::status_t & status,
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SlotMap * __smap=0)
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{
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// We need to define and return to opcode table from within this function
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// other inorder to take the addresses of the instruction bodies.
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#include "inc/opcode_table.h"
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if (get_table_mode)
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return opcode_table;
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// Declare virtual machine registers
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const instr * ip = program;
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const byte * dp = data;
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Machine::stack_t * sp = stack + Machine::STACK_GUARD,
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* const sb = sp;
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SlotMap & smap = *__smap;
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Segment & seg = smap.segment;
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slotref is = *__map,
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* map = __map,
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* const mapb = smap.begin()+smap.context();
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uint8 dir = _dir;
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int8 flags = 0;
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// start the program
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goto **ip;
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// Pull in the opcode definitions
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#include "inc/opcodes.h"
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end:
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__map = map;
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*__map = is;
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return sp;
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}
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}
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const opcode_t * Machine::getOpcodeTable() throw()
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{
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slotref * dummy;
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Machine::status_t dumstat = Machine::finished;
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return static_cast<const opcode_t *>(direct_run(true, 0, 0, 0, dummy, 0, dumstat));
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}
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Machine::stack_t Machine::run(const instr * program,
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const byte * data,
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slotref * & is)
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{
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assert(program != 0);
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const stack_t *sp = static_cast<const stack_t *>(
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direct_run(false, program, data, _stack, is, _map.dir(), _status, &_map));
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const stack_t ret = sp == _stack+STACK_GUARD+1 ? *sp-- : 0;
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check_final_stack(sp);
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return ret;
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}
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