js/src/jit/Recover.cpp@6474c204b198 (annotated)
js/src/jit/Recover.cpp
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- |
| michael@0 | 2 | * vim: set ts=8 sts=4 et sw=4 tw=99: |
| michael@0 | 3 | * This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 5 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | |
| michael@0 | 7 | #include "jit/Recover.h" |
| michael@0 | 8 | |
| michael@0 | 9 | #include "jit/IonSpewer.h" |
| michael@0 | 10 | #include "jit/MIR.h" |
| michael@0 | 11 | #include "jit/MIRGraph.h" |
| michael@0 | 12 | |
| michael@0 | 13 | using namespace js; |
| michael@0 | 14 | using namespace js::jit; |
| michael@0 | 15 | |
| michael@0 | 16 | void |
| michael@0 | 17 | RInstruction::readRecoverData(CompactBufferReader &reader, RInstructionStorage *raw) |
| michael@0 | 18 | { |
| michael@0 | 19 | uint32_t op = reader.readUnsigned(); |
| michael@0 | 20 | switch (Opcode(op)) { |
| michael@0 | 21 | case Recover_ResumePoint: |
| michael@0 | 22 | new (raw->addr()) RResumePoint(reader); |
| michael@0 | 23 | break; |
| michael@0 | 24 | default: |
| michael@0 | 25 | MOZ_ASSUME_UNREACHABLE("Bad decoding of the previous instruction?"); |
| michael@0 | 26 | break; |
| michael@0 | 27 | } |
| michael@0 | 28 | } |
| michael@0 | 29 | |
| michael@0 | 30 | bool |
| michael@0 | 31 | MResumePoint::writeRecoverData(CompactBufferWriter &writer) const |
| michael@0 | 32 | { |
| michael@0 | 33 | writer.writeUnsigned(uint32_t(RInstruction::Recover_ResumePoint)); |
| michael@0 | 34 | |
| michael@0 | 35 | MBasicBlock *bb = block(); |
| michael@0 | 36 | JSFunction *fun = bb->info().funMaybeLazy(); |
| michael@0 | 37 | JSScript *script = bb->info().script(); |
| michael@0 | 38 | uint32_t exprStack = stackDepth() - bb->info().ninvoke(); |
| michael@0 | 39 | |
| michael@0 | 40 | #ifdef DEBUG |
| michael@0 | 41 | // Ensure that all snapshot which are encoded can safely be used for |
| michael@0 | 42 | // bailouts. |
| michael@0 | 43 | if (GetIonContext()->cx) { |
| michael@0 | 44 | uint32_t stackDepth; |
| michael@0 | 45 | bool reachablePC; |
| michael@0 | 46 | jsbytecode *bailPC = pc(); |
| michael@0 | 47 | |
| michael@0 | 48 | if (mode() == MResumePoint::ResumeAfter) |
| michael@0 | 49 | bailPC = GetNextPc(pc()); |
| michael@0 | 50 | |
| michael@0 | 51 | if (!ReconstructStackDepth(GetIonContext()->cx, script, |
| michael@0 | 52 | bailPC, &stackDepth, &reachablePC)) |
| michael@0 | 53 | { |
| michael@0 | 54 | return false; |
| michael@0 | 55 | } |
| michael@0 | 56 | |
| michael@0 | 57 | if (reachablePC) { |
| michael@0 | 58 | if (JSOp(*bailPC) == JSOP_FUNCALL) { |
| michael@0 | 59 | // For fun.call(this, ...); the reconstructStackDepth will |
| michael@0 | 60 | // include the this. When inlining that is not included. So the |
| michael@0 | 61 | // exprStackSlots will be one less. |
| michael@0 | 62 | MOZ_ASSERT(stackDepth - exprStack <= 1); |
| michael@0 | 63 | } else if (JSOp(*bailPC) != JSOP_FUNAPPLY && |
| michael@0 | 64 | !IsGetPropPC(bailPC) && !IsSetPropPC(bailPC)) |
| michael@0 | 65 | { |
| michael@0 | 66 | // For fun.apply({}, arguments) the reconstructStackDepth will |
| michael@0 | 67 | // have stackdepth 4, but it could be that we inlined the |
| michael@0 | 68 | // funapply. In that case exprStackSlots, will have the real |
| michael@0 | 69 | // arguments in the slots and not be 4. |
| michael@0 | 70 | |
| michael@0 | 71 | // With accessors, we have different stack depths depending on |
| michael@0 | 72 | // whether or not we inlined the accessor, as the inlined stack |
| michael@0 | 73 | // contains a callee function that should never have been there |
| michael@0 | 74 | // and we might just be capturing an uneventful property site, |
| michael@0 | 75 | // in which case there won't have been any violence. |
| michael@0 | 76 | MOZ_ASSERT(exprStack == stackDepth); |
| michael@0 | 77 | } |
| michael@0 | 78 | } |
| michael@0 | 79 | } |
| michael@0 | 80 | #endif |
| michael@0 | 81 | |
| michael@0 | 82 | // Test if we honor the maximum of arguments at all times. This is a sanity |
| michael@0 | 83 | // check and not an algorithm limit. So check might be a bit too loose. +4 |
| michael@0 | 84 | // to account for scope chain, return value, this value and maybe |
| michael@0 | 85 | // arguments_object. |
| michael@0 | 86 | MOZ_ASSERT(CountArgSlots(script, fun) < SNAPSHOT_MAX_NARGS + 4); |
| michael@0 | 87 | |
| michael@0 | 88 | uint32_t implicit = StartArgSlot(script); |
| michael@0 | 89 | uint32_t formalArgs = CountArgSlots(script, fun); |
| michael@0 | 90 | uint32_t nallocs = formalArgs + script->nfixed() + exprStack; |
| michael@0 | 91 | |
| michael@0 | 92 | IonSpew(IonSpew_Snapshots, "Starting frame; implicit %u, formals %u, fixed %u, exprs %u", |
| michael@0 | 93 | implicit, formalArgs - implicit, script->nfixed(), exprStack); |
| michael@0 | 94 | |
| michael@0 | 95 | uint32_t pcoff = script->pcToOffset(pc()); |
| michael@0 | 96 | IonSpew(IonSpew_Snapshots, "Writing pc offset %u, nslots %u", pcoff, nallocs); |
| michael@0 | 97 | writer.writeUnsigned(pcoff); |
| michael@0 | 98 | writer.writeUnsigned(nallocs); |
| michael@0 | 99 | return true; |
| michael@0 | 100 | } |
| michael@0 | 101 | |
| michael@0 | 102 | RResumePoint::RResumePoint(CompactBufferReader &reader) |
| michael@0 | 103 | { |
| michael@0 | 104 | static_assert(sizeof(*this) <= sizeof(RInstructionStorage), |
| michael@0 | 105 | "Storage space is too small to decode this recover instruction."); |
| michael@0 | 106 | pcOffset_ = reader.readUnsigned(); |
| michael@0 | 107 | numOperands_ = reader.readUnsigned(); |
| michael@0 | 108 | IonSpew(IonSpew_Snapshots, "Read RResumePoint (pc offset %u, nslots %u)", |
| michael@0 | 109 | pcOffset_, numOperands_); |
| michael@0 | 110 | } |
