Sean Cannella
120 linhas
4.1 KiB
C++
120 linhas
4.1 KiB
C++
/*
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+----------------------------------------------------------------------+
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| HipHop for PHP |
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+----------------------------------------------------------------------+
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| Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com) |
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+----------------------------------------------------------------------+
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| This source file is subject to version 3.01 of the PHP license, |
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| that is bundled with this package in the file LICENSE, and is |
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| available through the world-wide-web at the following url: |
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| http://www.php.net/license/3_01.txt |
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| If you did not receive a copy of the PHP license and are unable to |
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| obtain it through the world-wide-web, please send a note to |
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| license@php.net so we can mail you a copy immediately. |
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+----------------------------------------------------------------------+
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*/
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#include "hphp/runtime/vm/jit/layout.h"
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#include <chrono>
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#include <random>
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#include "hphp/util/trace.h"
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#include "hphp/runtime/vm/jit/cfg.h"
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#include "hphp/runtime/vm/jit/state_vector.h"
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namespace HPHP { namespace JIT {
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TRACE_SET_MOD(hhir);
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//////////////////////////////////////////////////////////////////////
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namespace {
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void postorderWalk(smart::vector<Block*>& out,
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StateVector<Block,bool>& visited,
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Block* block) {
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if (visited[block]) return;
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visited[block] = true;
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if (auto t = block->taken()) postorderWalk(out, visited, t);
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if (auto n = block->next()) postorderWalk(out, visited, n);
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out.push_back(block);
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}
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smart::vector<Block*> rpoForCodegen(const IRFactory& factory, Block* head) {
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StateVector<Block,bool> visited(&factory, false);
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smart::vector<Block*> ret;
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ret.reserve(factory.numBlocks());
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postorderWalk(ret, visited, head);
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std::reverse(ret.begin(), ret.end());
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return ret;
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}
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}
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//////////////////////////////////////////////////////////////////////
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/*
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* Currently we have very limited control flow in any given tracelet,
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* so this just selects an appropriate reverse post order on the
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* blocks, and partitions the unlikely ones to astubs.
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*/
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LayoutInfo layoutBlocks(IRTrace* trace, const IRFactory& irFactory) {
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LayoutInfo ret;
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ret.blocks = rpoForCodegen(irFactory, trace->blocks().front());
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// Optionally stress test by randomizing the positions.
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if (RuntimeOption::EvalHHIRStressCodegenBlocks) {
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auto seed = std::chrono::system_clock::now().time_since_epoch().count();
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std::default_random_engine gen(seed);
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std::random_shuffle(ret.blocks.begin() + 1, ret.blocks.end(),
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[&](int i) { return gen() % i; });
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}
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// Partition into a and astubs, without changing relative order.
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ret.astubsIt = std::stable_partition(
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ret.blocks.begin(), ret.blocks.end(),
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[&] (Block* b) {
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return b->isMain() && b->hint() != Block::Hint::Unlikely;
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}
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);
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if (HPHP::Trace::moduleEnabled(HPHP::Trace::hhir, 5)) {
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std::string str = "CG Layout:";
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auto printRegion = [&] (const char* what,
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smart::vector<Block*>::iterator& it,
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smart::vector<Block*>::iterator stop) {
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folly::toAppend(what, &str);
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for (; it != stop; ++it) {
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folly::toAppend((*it)->id(), &str);
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folly::toAppend(" ", &str);
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}
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};
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auto it = ret.blocks.begin();
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printRegion("\n a: ", it, ret.astubsIt);
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printRegion("\n astubs: ", it, ret.blocks.end());
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HPHP::Trace::traceRelease("%s\n", str.c_str());
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}
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/*
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* No matter what happens above, it's going to be very broken if the
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* entry block isn't first, and it's going to perform poorly if the
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* main exit isn't the last block in a. Assert these.
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*
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* Note: this isn't the case if the main exit contains a return, but
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* we can revisit that later.
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*/
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if (!RuntimeOption::EvalHHIRStressCodegenBlocks) {
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always_assert(ret.blocks.front()->isEntry());
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always_assert((*boost::prior(ret.astubsIt))->isMainExit());
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}
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return ret;
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}
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//////////////////////////////////////////////////////////////////////
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}}
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