hphp/runtime/vm/jit/ir-unit.cpp

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2014 Facebook, Inc. (http://www.facebook.com)     |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #include "hphp/runtime/vm/jit/ir-unit.h"
  18
  19 #include "hphp/runtime/vm/jit/block.h"
  20 #include "hphp/runtime/vm/jit/cfg.h"
  21 #include "hphp/runtime/vm/jit/frame-state.h"
  22 #include "hphp/runtime/vm/jit/mc-generator.h"
  23 #include "hphp/runtime/vm/jit/timer.h"
  24
  25 namespace HPHP { namespace jit {
  26 ///////////////////////////////////////////////////////////////////////////////
  27
  28 TRACE_SET_MOD(hhir);
  29
  30 ///////////////////////////////////////////////////////////////////////////////
  31
  32 IRUnit::IRUnit(TransContext context)
  33   : m_context(context)
  34   , m_entry(defBlock())
  35 {}
  36
  37 IRInstruction* IRUnit::defLabel(unsigned numDst, BCMarker marker) {
  38   IRInstruction inst(DefLabel, marker);
  39   auto const label = clone(&inst);
  40   if (numDst > 0) {
  41     auto const dstsPtr = new (m_arena) SSATmp*[numDst];
  42     for (unsigned i = 0; i < numDst; ++i) {
  43       dstsPtr[i] = newSSATmp(label);
  44     }
  45     label->setDsts(numDst, dstsPtr);
  46   }
  47   return label;
  48 }
  49
  50 void IRUnit::expandLabel(IRInstruction* label, unsigned extraDst) {
  51   assertx(label->is(DefLabel));
  52   assertx(extraDst > 0);
  53   auto const dstsPtr = new (m_arena) SSATmp*[extraDst + label->numDsts()];
  54   unsigned i = 0;
  55   for (auto dst : label->dsts()) {
  56     dstsPtr[i++] = dst;
  57   }
  58   for (unsigned j = 0; j < extraDst; j++) {
  59     dstsPtr[i++] = newSSATmp(label);
  60   }
  61   label->setDsts(i, dstsPtr);
  62 }
  63
  64 void IRUnit::expandJmp(IRInstruction* jmp, SSATmp* value) {
  65   assertx(jmp->is(Jmp));
  66   std::vector<SSATmp*> newSrcs(jmp->numSrcs() + 1);
  67   size_t i = 0;
  68   for (auto src : jmp->srcs()) {
  69     newSrcs[i++] = src;
  70   }
  71   newSrcs[i++] = value;
  72   replace(jmp, Jmp, jmp->taken(), std::make_pair(i, &newSrcs[0]));
  73 }
  74
  75 Block* IRUnit::defBlock(Block::Hint hint) {
  76   FTRACE(2, "IRUnit defining B{}\n", m_nextBlockId);
  77   auto const block = new (m_arena) Block(m_nextBlockId++);
  78   block->setHint(hint);
  79   return block;
  80 }
  81
  82 SSATmp* IRUnit::cns(Type type) {
  83   assertx(type.hasConstVal() ||
  84          type.subtypeOfAny(TUninit, TInitNull, TNullptr));
  85   IRInstruction inst(DefConst, BCMarker{});
  86   inst.setTypeParam(type);
  87   if (SSATmp* tmp = m_constTable.lookup(&inst)) {
  88     assertx(tmp->type() == type);
  89     return tmp;
  90   }
  91   return m_constTable.insert(clone(&inst)->dst());
  92 }
  93
  94 ///////////////////////////////////////////////////////////////////////////////
  95
  96 /*
  97  * Returns true iff `block' ends the IR unit after finishing execution
  98  * of the bytecode instruction at `sk'.
  99  */
 100 static bool endsUnitAtSrcKey(const Block* block, SrcKey sk) {
 101   if (!block->isExitNoThrow()) return false;
 102
 103   const auto& inst = block->back();
 104   const auto  instSk = inst.marker().sk();
 105
 106   switch (inst.op()) {
 107     // These instructions end a unit after executing the bytecode
 108     // instruction they correspond to.
 109     case InterpOneCF:
 110     case JmpSSwitchDest:
 111     case JmpSwitchDest:
 112     case RaiseError:
 113       return instSk == sk;;
 114
 115     // The RetCtrl is generally ending a bytecode instruction, with the
 116     // exception being in an Await bytecode instruction, where we consider the
 117     // end of the bytecode instruction to be the non-suspending path.
 118     case RetCtrl:
 119     case AsyncRetCtrl:
 120       return inst.marker().sk().op() != Op::Await;
 121
 122     // A ReqBindJmp ends a unit and it jumps to the next instruction
 123     // to execute.
 124     case ReqBindJmp: {
 125       auto destOffset = inst.extra<ReqBindJmp>()->dest.offset();
 126       return sk.succOffsets().count(destOffset);
 127     }
 128
 129     default:
 130       return false;
 131   }
 132 }
 133
 134 Block* findMainExitBlock(const IRUnit& unit, SrcKey lastSk) {
 135   Block* mainExit = nullptr;
 136
 137   FTRACE(5, "findMainExitBlock: starting on unit:\n{}\n", show(unit));
 138
 139   for (auto block : rpoSortCfg(unit)) {
 140     if (endsUnitAtSrcKey(block, lastSk)) {
 141       if (mainExit == nullptr) {
 142         mainExit = block;
 143         continue;
 144       }
 145
 146       always_assert_flog(
 147         mainExit->hint() == Block::Hint::Unlikely ||
 148         block->hint() == Block::Hint::Unlikely,
 149         "findMainExit: 2 likely exits found: B{} and B{}\nlastSk = {}",
 150         mainExit->id(), block->id(), showShort(lastSk));
 151
 152       if (mainExit->hint() == Block::Hint::Unlikely) mainExit = block;
 153     }
 154   }
 155
 156   always_assert_flog(mainExit, "findMainExit: no exit found for lastSk = {}",
 157                      showShort(lastSk));
 158
 159   FTRACE(5, "findMainExitBlock: mainExit = B{}\n", mainExit->id());
 160
 161   return mainExit;
 162 }
 163
 164 ///////////////////////////////////////////////////////////////////////////////
 165
 166 }}