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/*
* Copyright (C) 2015-2016 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#if ENABLE(B3_JIT)
#include "AirArg.h"
#include "AirKind.h"
#include "B3StackmapSpecial.h"
#include <wtf/HashMap.h>
namespace JSC { namespace B3 {
namespace Air {
struct Inst;
}
// We want to lower Check instructions to a branch, but then we want to route that branch to our
// out-of-line code instead of doing anything else. For this reason, a CheckSpecial will remember
// which branch opcode we have selected along with the number of args in the overload we want. It
// will create an Inst with that opcode plus the appropriate args from the owning Inst whenever you
// call any of the callbacks.
//
// Note that for CheckAdd, CheckSub, and CheckMul we expect that the B3 arguments are the reverse
// of the Air arguments (Add(a, b) => Add32 b, a). Except:
// - CheckSub(0, x), which turns into BranchNeg32 x.
// - CheckMul(a, b), which turns into Mul32 b, a but we pass Any for a's ValueRep.
class CheckSpecial : public StackmapSpecial {
public:
// Support for hash consing these things.
class Key {
public:
Key()
: m_stackmapRole(SameAsRep)
, m_numArgs(0)
{
}
Key(Air::Kind kind, unsigned numArgs, RoleMode stackmapRole = SameAsRep)
: m_kind(kind)
, m_stackmapRole(stackmapRole)
, m_numArgs(numArgs)
{
}
explicit Key(const Air::Inst&);
bool operator==(const Key& other) const
{
return m_kind == other.m_kind
&& m_numArgs == other.m_numArgs
&& m_stackmapRole == other.m_stackmapRole;
}
bool operator!=(const Key& other) const
{
return !(*this == other);
}
explicit operator bool() const { return *this != Key(); }
Air::Kind kind() const { return m_kind; }
unsigned numArgs() const { return m_numArgs; }
RoleMode stackmapRole() const { return m_stackmapRole; }
void dump(PrintStream& out) const;
Key(WTF::HashTableDeletedValueType)
: m_stackmapRole(SameAsRep)
, m_numArgs(1)
{
}
bool isHashTableDeletedValue() const
{
return *this == Key(WTF::HashTableDeletedValue);
}
unsigned hash() const
{
// Seriously, we don't need to be smart here. It just doesn't matter.
return m_kind.hash() + m_numArgs + m_stackmapRole;
}
private:
Air::Kind m_kind;
RoleMode m_stackmapRole;
unsigned m_numArgs;
};
CheckSpecial(Air::Kind, unsigned numArgs, RoleMode stackmapRole = SameAsRep);
CheckSpecial(const Key&);
~CheckSpecial();
protected:
// Constructs and returns the Inst representing the branch that this will use.
Air::Inst hiddenBranch(const Air::Inst&) const;
void forEachArg(Air::Inst&, const ScopedLambda<Air::Inst::EachArgCallback>&) final;
bool isValid(Air::Inst&) final;
bool admitsStack(Air::Inst&, unsigned argIndex) final;
bool admitsExtendedOffsetAddr(Air::Inst&, unsigned) final;
std::optional<unsigned> shouldTryAliasingDef(Air::Inst&) final;
// NOTE: the generate method will generate the hidden branch and then register a LatePath that
// generates the stackmap. Super crazy dude!
CCallHelpers::Jump generate(Air::Inst&, CCallHelpers&, Air::GenerationContext&) final;
void dumpImpl(PrintStream&) const final;
void deepDumpImpl(PrintStream&) const final;
private:
Air::Kind m_checkKind;
RoleMode m_stackmapRole;
unsigned m_numCheckArgs;
};
struct CheckSpecialKeyHash {
static unsigned hash(const CheckSpecial::Key& key) { return key.hash(); }
static bool equal(const CheckSpecial::Key& a, const CheckSpecial::Key& b) { return a == b; }
static const bool safeToCompareToEmptyOrDeleted = true;
};
} } // namespace JSC::B3
namespace WTF {
template<typename T> struct DefaultHash;
template<> struct DefaultHash<JSC::B3::CheckSpecial::Key> {
typedef JSC::B3::CheckSpecialKeyHash Hash;
};
template<typename T> struct HashTraits;
template<> struct HashTraits<JSC::B3::CheckSpecial::Key> : SimpleClassHashTraits<JSC::B3::CheckSpecial::Key> {
// I don't want to think about this very hard, it's not worth it. I'm a be conservative.
static const bool emptyValueIsZero = false;
};
} // namespace WTF
#endif // ENABLE(B3_JIT)