1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/jit/BaselineFrameInfo.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,183 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#include "jit/BaselineFrameInfo.h"
1.11 +
1.12 +#ifdef DEBUG
1.13 +# include "jit/BytecodeAnalysis.h"
1.14 +#endif
1.15 +
1.16 +using namespace js;
1.17 +using namespace js::jit;
1.18 +
1.19 +bool
1.20 +FrameInfo::init(TempAllocator &alloc)
1.21 +{
1.22 + // One slot is always needed for this/arguments type checks.
1.23 + size_t nstack = Max(script->nslots() - script->nfixed(), size_t(1));
1.24 + if (!stack.init(alloc, nstack))
1.25 + return false;
1.26 +
1.27 + return true;
1.28 +}
1.29 +
1.30 +void
1.31 +FrameInfo::sync(StackValue *val)
1.32 +{
1.33 + switch (val->kind()) {
1.34 + case StackValue::Stack:
1.35 + break;
1.36 + case StackValue::LocalSlot:
1.37 + masm.pushValue(addressOfLocal(val->localSlot()));
1.38 + break;
1.39 + case StackValue::ArgSlot:
1.40 + masm.pushValue(addressOfArg(val->argSlot()));
1.41 + break;
1.42 + case StackValue::ThisSlot:
1.43 + masm.pushValue(addressOfThis());
1.44 + break;
1.45 + case StackValue::Register:
1.46 + masm.pushValue(val->reg());
1.47 + break;
1.48 + case StackValue::Constant:
1.49 + masm.pushValue(val->constant());
1.50 + break;
1.51 + default:
1.52 + MOZ_ASSUME_UNREACHABLE("Invalid kind");
1.53 + }
1.54 +
1.55 + val->setStack();
1.56 +}
1.57 +
1.58 +void
1.59 +FrameInfo::syncStack(uint32_t uses)
1.60 +{
1.61 + JS_ASSERT(uses <= stackDepth());
1.62 +
1.63 + uint32_t depth = stackDepth() - uses;
1.64 +
1.65 + for (uint32_t i = 0; i < depth; i++) {
1.66 + StackValue *current = &stack[i];
1.67 + sync(current);
1.68 + }
1.69 +}
1.70 +
1.71 +uint32_t
1.72 +FrameInfo::numUnsyncedSlots()
1.73 +{
1.74 + // Start at the bottom, find the first value that's not synced.
1.75 + uint32_t i = 0;
1.76 + for (; i < stackDepth(); i++) {
1.77 + if (peek(-int32_t(i + 1))->kind() == StackValue::Stack)
1.78 + break;
1.79 + }
1.80 + return i;
1.81 +}
1.82 +
1.83 +void
1.84 +FrameInfo::popValue(ValueOperand dest)
1.85 +{
1.86 + StackValue *val = peek(-1);
1.87 +
1.88 + switch (val->kind()) {
1.89 + case StackValue::Constant:
1.90 + masm.moveValue(val->constant(), dest);
1.91 + break;
1.92 + case StackValue::LocalSlot:
1.93 + masm.loadValue(addressOfLocal(val->localSlot()), dest);
1.94 + break;
1.95 + case StackValue::ArgSlot:
1.96 + masm.loadValue(addressOfArg(val->argSlot()), dest);
1.97 + break;
1.98 + case StackValue::ThisSlot:
1.99 + masm.loadValue(addressOfThis(), dest);
1.100 + break;
1.101 + case StackValue::Stack:
1.102 + masm.popValue(dest);
1.103 + break;
1.104 + case StackValue::Register:
1.105 + masm.moveValue(val->reg(), dest);
1.106 + break;
1.107 + default:
1.108 + MOZ_ASSUME_UNREACHABLE("Invalid kind");
1.109 + }
1.110 +
1.111 + // masm.popValue already adjusted the stack pointer, don't do it twice.
1.112 + pop(DontAdjustStack);
1.113 +}
1.114 +
1.115 +void
1.116 +FrameInfo::popRegsAndSync(uint32_t uses)
1.117 +{
1.118 + // x86 has only 3 Value registers. Only support 2 regs here for now,
1.119 + // so that there's always a scratch Value register for reg -> reg
1.120 + // moves.
1.121 + JS_ASSERT(uses > 0);
1.122 + JS_ASSERT(uses <= 2);
1.123 + JS_ASSERT(uses <= stackDepth());
1.124 +
1.125 + syncStack(uses);
1.126 +
1.127 + switch (uses) {
1.128 + case 1:
1.129 + popValue(R0);
1.130 + break;
1.131 + case 2: {
1.132 + // If the second value is in R1, move it to R2 so that it's not
1.133 + // clobbered by the first popValue.
1.134 + StackValue *val = peek(-2);
1.135 + if (val->kind() == StackValue::Register && val->reg() == R1) {
1.136 + masm.moveValue(R1, R2);
1.137 + val->setRegister(R2);
1.138 + }
1.139 + popValue(R1);
1.140 + popValue(R0);
1.141 + break;
1.142 + }
1.143 + default:
1.144 + MOZ_ASSUME_UNREACHABLE("Invalid uses");
1.145 + }
1.146 +}
1.147 +
1.148 +#ifdef DEBUG
1.149 +void
1.150 +FrameInfo::assertValidState(const BytecodeInfo &info)
1.151 +{
1.152 + // Check stack depth.
1.153 + JS_ASSERT(stackDepth() == info.stackDepth);
1.154 +
1.155 + // Start at the bottom, find the first value that's not synced.
1.156 + uint32_t i = 0;
1.157 + for (; i < stackDepth(); i++) {
1.158 + if (stack[i].kind() != StackValue::Stack)
1.159 + break;
1.160 + }
1.161 +
1.162 + // Assert all values on top of it are also not synced.
1.163 + for (; i < stackDepth(); i++)
1.164 + JS_ASSERT(stack[i].kind() != StackValue::Stack);
1.165 +
1.166 + // Assert every Value register is used by at most one StackValue.
1.167 + // R2 is used as scratch register by the compiler and FrameInfo,
1.168 + // so it shouldn't be used for StackValues.
1.169 + bool usedR0 = false, usedR1 = false;
1.170 +
1.171 + for (i = 0; i < stackDepth(); i++) {
1.172 + if (stack[i].kind() == StackValue::Register) {
1.173 + ValueOperand reg = stack[i].reg();
1.174 + if (reg == R0) {
1.175 + JS_ASSERT(!usedR0);
1.176 + usedR0 = true;
1.177 + } else if (reg == R1) {
1.178 + JS_ASSERT(!usedR1);
1.179 + usedR1 = true;
1.180 + } else {
1.181 + MOZ_ASSUME_UNREACHABLE("Invalid register");
1.182 + }
1.183 + }
1.184 + }
1.185 +}
1.186 +#endif
