hphp/runtime/vm/translator/immstack.cpp

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010- 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/translator/immstack.h"
  18
  19 namespace HPHP {
  20 ///////////////////////////////////////////////////////////////////////////////
  21
  22 void ImmStack::processOpcode(const Opcode* opcode) {
  23   StackTransInfo sti = instrStackTransInfo(opcode);
  24   if (sti.kind == StackTransInfo::PushPop) {
  25     for (int i = 0; i < sti.numPops; i++) {
  26       pop();
  27     }
  28     for (int i = 0; i < sti.numPushes; i++) {
  29       pushUnknown();
  30     }
  31   } else if (sti.kind == StackTransInfo::InsertMid) {
  32     insUnknown(sti.pos);
  33   } else {
  34     assert(false);
  35   }
  36 }
  37
  38 void ImmStack::pushUnknown() {
  39   StackItem item;
  40
  41   item.type = StackItem::StackType_Unknown;
  42   m_stack.push_back(item);
  43 }
  44
  45 void ImmStack::insUnknown(int pos) {
  46   int k = m_stack.size() - 1 - pos;
  47   if (k >= 0 && k < (int)m_stack.size()) {
  48     StackItem item;
  49     item.type = StackItem::StackType_Unknown;
  50     m_stack.insert(m_stack.begin() + k, item);
  51   }
  52 }
  53
  54 void ImmStack::pop() {
  55   // Since we only process on the basic block level, we obviously can pop
  56   //   locations that we don't track. We treat all these locations as unknowns.
  57
  58   if (!m_stack.empty()) {
  59     m_stack.pop_back();
  60   }
  61 }
  62
  63 void ImmStack::pushInt(int64_t value) {
  64   StackItem item;
  65
  66   item.type = StackItem::StackType_Int;
  67   item.i64a = value;
  68
  69   m_stack.push_back(item);
  70 }
  71
  72 void ImmStack::pushLitstr(Id value) {
  73   StackItem item;
  74
  75   item.type = StackItem::StackType_Litstr;
  76   item.sa = value;
  77
  78   m_stack.push_back(item);
  79 }
  80
  81 ImmStack::StackItem &ImmStack::get(int above) {
  82   always_assert(above >= 0 && (size_t)above < m_stack.size());
  83
  84   return m_stack[m_stack.size() - above - 1];
  85 }
  86
  87 bool ImmStack::isInt(int above) {
  88   if (above >= (int)m_stack.size()) {
  89     return false;
  90   }
  91
  92   return get(above).type == StackItem::StackType_Int;
  93 }
  94
  95 bool ImmStack::isLitstr(int above) {
  96   if (above >= (int)m_stack.size()) {
  97     return false;
  98   }
  99
 100   return get(above).type == StackItem::StackType_Litstr;
 101 }
 102
 103 }