1/*
2 * Copyright (C) 2013, 2014 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "FTLOSREntry.h"
28
29#include "CallFrame.h"
30#include "CodeBlock.h"
31#include "DFGJITCode.h"
32#include "FTLForOSREntryJITCode.h"
33#include "JSStackInlines.h"
34#include "OperandsInlines.h"
35#include "JSCInlines.h"
36
37#if ENABLE(FTL_JIT)
38
39namespace JSC { namespace FTL {
40
41void* prepareOSREntry(
42    ExecState* exec, CodeBlock* dfgCodeBlock, CodeBlock* entryCodeBlock,
43    unsigned bytecodeIndex, unsigned streamIndex)
44{
45    VM& vm = exec->vm();
46    CodeBlock* baseline = dfgCodeBlock->baselineVersion();
47    ExecutableBase* executable = dfgCodeBlock->ownerExecutable();
48    DFG::JITCode* dfgCode = dfgCodeBlock->jitCode()->dfg();
49    ForOSREntryJITCode* entryCode = entryCodeBlock->jitCode()->ftlForOSREntry();
50
51    if (Options::verboseOSR()) {
52        dataLog(
53            "FTL OSR from ", *dfgCodeBlock, " to ", *entryCodeBlock, " at bc#",
54            bytecodeIndex, ".\n");
55    }
56
57    if (bytecodeIndex != entryCode->bytecodeIndex()) {
58        if (Options::verboseOSR())
59            dataLog("    OSR failed because we don't have an entrypoint for bc#", bytecodeIndex, "; ours is for bc#", entryCode->bytecodeIndex());
60        return 0;
61    }
62
63    Operands<JSValue> values;
64    dfgCode->reconstruct(
65        exec, dfgCodeBlock, CodeOrigin(bytecodeIndex), streamIndex, values);
66
67    if (Options::verboseOSR())
68        dataLog("    Values at entry: ", values, "\n");
69
70    for (int argument = values.numberOfArguments(); argument--;) {
71        JSValue valueOnStack = exec->r(virtualRegisterForArgument(argument).offset()).jsValue();
72        JSValue reconstructedValue = values.argument(argument);
73        if (valueOnStack == reconstructedValue || !argument)
74            continue;
75        dataLog("Mismatch between reconstructed values and the the value on the stack for argument arg", argument, " for ", *entryCodeBlock, " at bc#", bytecodeIndex, ":\n");
76        dataLog("    Value on stack: ", valueOnStack, "\n");
77        dataLog("    Reconstructed value: ", reconstructedValue, "\n");
78        RELEASE_ASSERT_NOT_REACHED();
79    }
80
81    RELEASE_ASSERT(
82        static_cast<int>(values.numberOfLocals()) == baseline->m_numCalleeRegisters);
83
84    EncodedJSValue* scratch = static_cast<EncodedJSValue*>(
85        entryCode->entryBuffer()->dataBuffer());
86
87    for (int local = values.numberOfLocals(); local--;)
88        scratch[local] = JSValue::encode(values.local(local));
89
90    int stackFrameSize = entryCode->common.requiredRegisterCountForExecutionAndExit();
91    if (!vm.interpreter->stack().ensureCapacityFor(&exec->registers()[virtualRegisterForLocal(stackFrameSize - 1).offset()])) {
92        if (Options::verboseOSR())
93            dataLog("    OSR failed because stack growth failed.\n");
94        return 0;
95    }
96
97    exec->setCodeBlock(entryCodeBlock);
98
99    void* result = entryCode->addressForCall(
100        vm, executable, ArityCheckNotRequired,
101        RegisterPreservationNotRequired).executableAddress();
102    if (Options::verboseOSR())
103        dataLog("    Entry will succeed, going to address", RawPointer(result), "\n");
104
105    return result;
106}
107
108} } // namespace JSC::FTL
109
110#endif // ENABLE(FTL_JIT)
111
112
113