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
/* -*- 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/Jit.h"

#include "jit/BaselineJIT.h"
#include "jit/Ion.h"
#include "jit/JitCommon.h"
#include "jit/JitRealm.h"
#include "vm/Interpreter.h"

#include "vm/Stack-inl.h"

using namespace js;
using namespace js::jit;

static EnterJitStatus JS_HAZ_JSNATIVE_CALLER EnterJit(JSContext* cx,
                                                      RunState& state,
                                                      uint8_t* code) {
  // We don't want to call the interpreter stub here (because
  // C++ -> interpreterStub -> C++ is slower than staying in C++).
  MOZ_ASSERT(code);
  MOZ_ASSERT(code != cx->runtime()->jitRuntime()->interpreterStub().value);
  MOZ_ASSERT(IsBaselineInterpreterEnabled());

  if (!CheckRecursionLimit(cx)) {
    return EnterJitStatus::Error;
  }

#ifdef DEBUG
  // Assert we don't GC before entering JIT code. A GC could discard JIT code
  // or move the function stored in the CalleeToken (it won't be traced at
  // this point). We use Maybe<> here so we can call reset() to call the
  // AutoAssertNoGC destructor before we enter JIT code.
  mozilla::Maybe<JS::AutoAssertNoGC> nogc;
  nogc.emplace(cx);
#endif

  JSScript* script = state.script();
  size_t numActualArgs;
  bool constructing;
  size_t maxArgc;
  Value* maxArgv;
  JSObject* envChain;
  CalleeToken calleeToken;

  if (state.isInvoke()) {
    const CallArgs& args = state.asInvoke()->args();
    numActualArgs = args.length();

    if (TooManyActualArguments(numActualArgs)) {
      // Too many arguments for Ion. Baseline supports more actual
      // arguments, so in that case force Baseline code.
      if (numActualArgs > BASELINE_MAX_ARGS_LENGTH) {
        return EnterJitStatus::NotEntered;
      }
      if (script->hasBaselineScript()) {
        code = script->baselineScript()->method()->raw();
      } else {
        code = cx->runtime()->jitRuntime()->baselineInterpreter().codeRaw();
      }
    }

    constructing = state.asInvoke()->constructing();
    maxArgc = args.length() + 1;
    maxArgv = args.array() - 1;  // -1 to include |this|
    envChain = nullptr;
    calleeToken = CalleeToToken(&args.callee().as<JSFunction>(), constructing);

    unsigned numFormals = script->functionNonDelazifying()->nargs();
    if (numFormals > numActualArgs) {
      code = cx->runtime()->jitRuntime()->getArgumentsRectifier().value;
    }
  } else {
    numActualArgs = 0;
    constructing = false;
    if (script->isDirectEvalInFunction()) {
      if (state.asExecute()->newTarget().isNull()) {
        ScriptFrameIter iter(cx);
        state.asExecute()->setNewTarget(iter.newTarget());
      }
      maxArgc = 1;
      maxArgv = state.asExecute()->addressOfNewTarget();
    } else {
      maxArgc = 0;
      maxArgv = nullptr;
    }
    envChain = state.asExecute()->environmentChain();
    calleeToken = CalleeToToken(state.script());
  }

  // Caller must construct |this| before invoking the function.
  MOZ_ASSERT_IF(constructing, maxArgv[0].isObject() ||
                                  maxArgv[0].isMagic(JS_UNINITIALIZED_LEXICAL));

  RootedValue result(cx, Int32Value(numActualArgs));
  {
    AssertRealmUnchanged aru(cx);
    ActivationEntryMonitor entryMonitor(cx, calleeToken);
    JitActivation activation(cx);
    EnterJitCode enter = cx->runtime()->jitRuntime()->enterJit();

#ifdef DEBUG
    nogc.reset();
#endif
    CALL_GENERATED_CODE(enter, code, maxArgc, maxArgv, /* osrFrame = */ nullptr,
                        calleeToken, envChain, /* osrNumStackValues = */ 0,
                        result.address());
  }

  MOZ_ASSERT(!cx->hasIonReturnOverride());

  // Release temporary buffer used for OSR into Ion.
  cx->freeOsrTempData();

  if (result.isMagic()) {
    MOZ_ASSERT(result.isMagic(JS_ION_ERROR));
    return EnterJitStatus::Error;
  }

  // Jit callers wrap primitive constructor return, except for derived
  // class constructors, which are forced to do it themselves.
  if (constructing && result.isPrimitive()) {
    MOZ_ASSERT(maxArgv[0].isObject());
    result = maxArgv[0];
  }

  state.setReturnValue(result);
  return EnterJitStatus::Ok;
}

EnterJitStatus js::jit::MaybeEnterJit(JSContext* cx, RunState& state) {
  if (!IsBaselineInterpreterEnabled()) {
    // All JITs are disabled.
    return EnterJitStatus::NotEntered;
  }

  JSScript* script = state.script();

  uint8_t* code = script->jitCodeRaw();
  do {
    // Make sure we can enter Baseline Interpreter code. Note that the prologue
    // has warm-up checks to tier up if needed.
    if (script->hasJitScript()) {
      break;
    }

    script->incWarmUpCounter();

    // Try to Ion-compile.
    if (jit::IsIonEnabled()) {
      jit::MethodStatus status = jit::CanEnterIon(cx, state);
      if (status == jit::Method_Error) {
        return EnterJitStatus::Error;
      }
      if (status == jit::Method_Compiled) {
        code = script->jitCodeRaw();
        break;
      }
    }

    // Try to Baseline-compile.
    if (jit::IsBaselineJitEnabled()) {
      jit::MethodStatus status =
          jit::CanEnterBaselineMethod<BaselineTier::Compiler>(cx, state);
      if (status == jit::Method_Error) {
        return EnterJitStatus::Error;
      }
      if (status == jit::Method_Compiled) {
        code = script->jitCodeRaw();
        break;
      }
    }

    // Try to enter the Baseline Interpreter.
    if (IsBaselineInterpreterEnabled()) {
      jit::MethodStatus status =
          jit::CanEnterBaselineMethod<BaselineTier::Interpreter>(cx, state);
      if (status == jit::Method_Error) {
        return EnterJitStatus::Error;
      }
      if (status == jit::Method_Compiled) {
        code = script->jitCodeRaw();
        break;
      }
    }

    return EnterJitStatus::NotEntered;
  } while (false);

  return EnterJit(cx, state, code);
}