DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (b6d82b1a6b02)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "jit/BaselineFrameInfo.h"

#include "jit/BaselineIC.h"
#ifdef DEBUG
#  include "jit/BytecodeAnalysis.h"
#endif

#include "jit/BaselineFrameInfo-inl.h"
#include "jit/MacroAssembler-inl.h"

using namespace js;
using namespace js::jit;

bool CompilerFrameInfo::init(TempAllocator& alloc) {
  // An extra slot is needed for global scopes because INITGLEXICAL (stack
  // depth 1) is compiled as a SETPROP (stack depth 2) on the global lexical
  // scope.
  size_t extra = script->isGlobalCode() ? 1 : 0;
  size_t nstack =
      Max(script->nslots() - script->nfixed(), size_t(MinJITStackSize)) + extra;
  if (!stack.init(alloc, nstack)) {
    return false;
  }

  return true;
}

void CompilerFrameInfo::sync(StackValue* val) {
  switch (val->kind()) {
    case StackValue::Stack:
      break;
    case StackValue::LocalSlot:
      masm.pushValue(addressOfLocal(val->localSlot()));
      break;
    case StackValue::ArgSlot:
      masm.pushValue(addressOfArg(val->argSlot()));
      break;
    case StackValue::ThisSlot:
      masm.pushValue(addressOfThis());
      break;
    case StackValue::EvalNewTargetSlot:
      MOZ_ASSERT(script->isForEval());
      masm.pushValue(addressOfEvalNewTarget());
      break;
    case StackValue::Register:
      masm.pushValue(val->reg());
      break;
    case StackValue::Constant:
      masm.pushValue(val->constant());
      break;
    default:
      MOZ_CRASH("Invalid kind");
  }

  val->setStack();
}

void CompilerFrameInfo::syncStack(uint32_t uses) {
  MOZ_ASSERT(uses <= stackDepth());

  uint32_t depth = stackDepth() - uses;

  for (uint32_t i = 0; i < depth; i++) {
    StackValue* current = &stack[i];
    sync(current);
  }
}

uint32_t CompilerFrameInfo::numUnsyncedSlots() {
  // Start at the bottom, find the first value that's not synced.
  uint32_t i = 0;
  for (; i < stackDepth(); i++) {
    if (peek(-int32_t(i + 1))->kind() == StackValue::Stack) {
      break;
    }
  }
  return i;
}

void CompilerFrameInfo::popValue(ValueOperand dest) {
  StackValue* val = peek(-1);

  switch (val->kind()) {
    case StackValue::Constant:
      masm.moveValue(val->constant(), dest);
      break;
    case StackValue::LocalSlot:
      masm.loadValue(addressOfLocal(val->localSlot()), dest);
      break;
    case StackValue::ArgSlot:
      masm.loadValue(addressOfArg(val->argSlot()), dest);
      break;
    case StackValue::ThisSlot:
      masm.loadValue(addressOfThis(), dest);
      break;
    case StackValue::EvalNewTargetSlot:
      masm.loadValue(addressOfEvalNewTarget(), dest);
      break;
    case StackValue::Stack:
      masm.popValue(dest);
      break;
    case StackValue::Register:
      masm.moveValue(val->reg(), dest);
      break;
    default:
      MOZ_CRASH("Invalid kind");
  }

  // masm.popValue already adjusted the stack pointer, don't do it twice.
  pop(DontAdjustStack);
}

void CompilerFrameInfo::popRegsAndSync(uint32_t uses) {
  // x86 has only 3 Value registers. Only support 2 regs here for now,
  // so that there's always a scratch Value register for reg -> reg
  // moves.
  MOZ_ASSERT(uses > 0);
  MOZ_ASSERT(uses <= 2);
  MOZ_ASSERT(uses <= stackDepth());

  syncStack(uses);

  switch (uses) {
    case 1:
      popValue(R0);
      break;
    case 2: {
      // If the second value is in R1, move it to R2 so that it's not
      // clobbered by the first popValue.
      StackValue* val = peek(-2);
      if (val->kind() == StackValue::Register && val->reg() == R1) {
        masm.moveValue(R1, ValueOperand(R2));
        val->setRegister(R2);
      }
      popValue(R1);
      popValue(R0);
      break;
    }
    default:
      MOZ_CRASH("Invalid uses");
  }
}

void InterpreterFrameInfo::popRegsAndSync(uint32_t uses) {
  switch (uses) {
    case 1:
      popValue(R0);
      break;
    case 2: {
      popValue(R1);
      popValue(R0);
      break;
    }
    default:
      MOZ_CRASH("Invalid uses");
  }
}

void InterpreterFrameInfo::bumpInterpreterICEntry() {
  masm.addPtr(Imm32(sizeof(ICEntry)), addressOfInterpreterICEntry());
}

void CompilerFrameInfo::storeStackValue(int32_t depth, const Address& dest,
                                        const ValueOperand& scratch) {
  const StackValue* source = peek(depth);
  switch (source->kind()) {
    case StackValue::Constant:
      masm.storeValue(source->constant(), dest);
      break;
    case StackValue::Register:
      masm.storeValue(source->reg(), dest);
      break;
    case StackValue::LocalSlot:
      masm.loadValue(addressOfLocal(source->localSlot()), scratch);
      masm.storeValue(scratch, dest);
      break;
    case StackValue::ArgSlot:
      masm.loadValue(addressOfArg(source->argSlot()), scratch);
      masm.storeValue(scratch, dest);
      break;
    case StackValue::ThisSlot:
      masm.loadValue(addressOfThis(), scratch);
      masm.storeValue(scratch, dest);
      break;
    case StackValue::EvalNewTargetSlot:
      MOZ_ASSERT(script->isForEval());
      masm.loadValue(addressOfEvalNewTarget(), scratch);
      masm.storeValue(scratch, dest);
      break;
    case StackValue::Stack:
      masm.loadValue(addressOfStackValue(depth), scratch);
      masm.storeValue(scratch, dest);
      break;
    default:
      MOZ_CRASH("Invalid kind");
  }
}

#ifdef DEBUG
void CompilerFrameInfo::assertValidState(const BytecodeInfo& info) {
  // Check stack depth.
  MOZ_ASSERT(stackDepth() == info.stackDepth);

  // Start at the bottom, find the first value that's not synced.
  uint32_t i = 0;
  for (; i < stackDepth(); i++) {
    if (stack[i].kind() != StackValue::Stack) {
      break;
    }
  }

  // Assert all values on top of it are also not synced.
  for (; i < stackDepth(); i++) {
    MOZ_ASSERT(stack[i].kind() != StackValue::Stack);
  }

  // Assert every Value register is used by at most one StackValue.
  // R2 is used as scratch register by the compiler and FrameInfo,
  // so it shouldn't be used for StackValues.
  bool usedR0 = false, usedR1 = false;

  for (i = 0; i < stackDepth(); i++) {
    if (stack[i].kind() == StackValue::Register) {
      ValueOperand reg = stack[i].reg();
      if (reg == R0) {
        MOZ_ASSERT(!usedR0);
        usedR0 = true;
      } else if (reg == R1) {
        MOZ_ASSERT(!usedR1);
        usedR1 = true;
      } else {
        MOZ_CRASH("Invalid register");
      }
    }
  }
}
#endif