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/*
* Copyright (C) 2011-2021 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
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "JITCompilationMode.h"
#if ENABLE(DFG_JIT)
#include "Options.h"
#include <limits.h>
#include <wtf/text/StringImpl.h>
namespace JSC { namespace DFG {
struct Node;
typedef uint32_t BlockIndex;
static constexpr BlockIndex NoBlock = UINT_MAX;
extern const char* const tierName;
// Use RefChildren if the child ref counts haven't already been adjusted using
// other means and either of the following is true:
// - The node you're creating is MustGenerate.
// - The place where you're inserting a reference to the node you're creating
// will not also do RefChildren.
enum RefChildrenMode {
RefChildren,
DontRefChildren
};
// Use RefNode if you know that the node will be used from another node, and you
// will not already be ref'ing the node to account for that use.
enum RefNodeMode {
RefNode,
DontRefNode
};
enum SwitchKind {
SwitchImm,
SwitchChar,
SwitchString,
SwitchCell
};
inline bool verboseCompilationEnabled(JITCompilationMode mode = JITCompilationMode::DFG)
{
return Options::verboseCompilation() || Options::dumpGraphAtEachPhase() || (isFTL(mode) && Options::verboseFTLCompilation());
}
inline bool logCompilationChanges(JITCompilationMode mode = JITCompilationMode::DFG)
{
return verboseCompilationEnabled(mode) || Options::logCompilationChanges();
}
inline bool shouldDumpGraphAtEachPhase(JITCompilationMode mode = JITCompilationMode::DFG)
{
if (isFTL(mode))
return Options::dumpGraphAtEachPhase() || Options::dumpDFGFTLGraphAtEachPhase();
return Options::dumpGraphAtEachPhase() || Options::dumpDFGGraphAtEachPhase();
}
inline bool validationEnabled()
{
#if ASSERT_ENABLED
return true;
#else
return Options::validateGraph() || Options::validateGraphAtEachPhase();
#endif
}
inline bool constexpr enableInt52()
{
#if USE(JSVALUE64)
return true;
#else
return false;
#endif
}
// The prediction propagator effectively does four passes, with the last pass
// being done by the separate FixuPhase.
enum PredictionPass {
// We're converging in a straight-forward forward flow fixpoint. This is the
// most conventional part of the propagator - it makes only monotonic decisions
// based on value profiles and rare case profiles. It ignores baseline JIT rare
// case profiles. The goal here is to develop a good guess of which variables
// are likely to be purely numerical, which generally doesn't require knowing
// the rare case profiles.
PrimaryPass,
// At this point we know what is numerical and what isn't. Non-numerical inputs
// to arithmetic operations will not have useful information in the Baseline JIT
// rare case profiles because Baseline may take slow path on non-numerical
// inputs even if the DFG could handle the input on the fast path. Boolean
// inputs are the most obvious example. This pass of prediction propagation will
// use Baseline rare case profiles for purely numerical operations and it will
// ignore them for everything else. The point of this pass is to develop a good
// guess of which variables are likely to be doubles.
//
// This pass is intentionally weird and goes against what is considered good
// form when writing a static analysis: a new data flow of booleans will cause
// us to ignore rare case profiles except that by then, we will have already
// propagated double types based on our prior assumption that we shouldn't
// ignore rare cases. This probably won't happen because the PrimaryPass is
// almost certainly going to establish what is and isn't numerical. But it's
// conceivable that during this pass we will discover a new boolean data flow.
// This ends up being sound because the prediction propagator could literally
// make any guesses it wants and still be sound (worst case, we OSR exit more
// often or use too general of types are run a bit slower). This will converge
// because we force monotonicity on the types of nodes and variables. So, the
// worst thing that can happen is that we violate basic laws of theoretical
// decency.
RareCasePass,
// At this point we know what is numerical and what isn't, and we also know what
// is a double and what isn't. So, we start forcing variables to be double.
// Doing so may have a cascading effect so this is a fixpoint. It's monotonic
// in the sense that once a variable is forced double, it cannot be forced in
// the other direction.
DoubleVotingPass,
// This pass occurs once we have converged. At this point we are just installing
// type checks based on the conclusions we have already reached. It's important
// for this pass to reach the same conclusions that DoubleVotingPass reached.
FixupPass
};
enum StructureRegistrationState { HaveNotStartedRegistering, AllStructuresAreRegistered };
enum StructureRegistrationResult { StructureRegisteredNormally, StructureRegisteredAndWatched };
enum OptimizationFixpointState { BeforeFixpoint, FixpointNotConverged, FixpointConverged };
// Describes the form you can expect the entire graph to be in.
enum GraphForm {
// LoadStore form means that basic blocks may freely use GetLocal, SetLocal,
// and Flush for accessing local variables and indicating where their live
// ranges ought to be. Data flow between local accesses is implicit. Liveness
// is only explicit at block heads (variablesAtHead). This is only used by
// the DFG simplifier and is only preserved by same.
//
// For example, LoadStore form gives no easy way to determine which SetLocal's
// flow into a GetLocal. As well, LoadStore form implies no restrictions on
// redundancy: you can freely emit multiple GetLocals, or multiple SetLocals
// (or any combination thereof) to the same local in the same block. LoadStore
// form does not require basic blocks to declare how they affect or use locals,
// other than implicitly by using the local ops and by preserving
// variablesAtHead. Finally, LoadStore allows flexibility in how liveness of
// locals is extended; for example you can replace a GetLocal with a Phantom
// and so long as the Phantom retains the GetLocal's children (i.e. the Phi
// most likely) then it implies that the local is still live but that it need
// not be stored to the stack necessarily. This implies that Phantom can
// reference nodes that have no result, as long as those nodes are valid
// GetLocal children (i.e. Phi, SetLocal, SetArgumentDefinitely, SetArgumentMaybe).
//
// LoadStore form also implies that Phis need not have children. By default,
// they end up having no children if you enter LoadStore using the canonical
// way (call Graph::dethread).
//
// LoadStore form is suitable for CFG transformations, as well as strength
// reduction, folding, and CSE.
LoadStore,
// ThreadedCPS form means that basic blocks list up-front which locals they
// expect to be live at the head, and which locals they make available at the
// tail. ThreadedCPS form also implies that:
//
// - GetLocals and SetLocals are not redundant within a basic block.
//
// - All GetLocals and Flushes are linked directly to the last access point
// of the variable, which must not be another GetLocal.
//
// - Phantom(Phi) is not legal, but PhantomLocal is.
//
// ThreadedCPS form is suitable for data flow analysis (CFA, prediction
// propagation), register allocation, and code generation.
ThreadedCPS,
// SSA form. See DFGSSAConversionPhase.h for a description.
SSA
};
// Describes the state of the UnionFind structure of VariableAccessData's.
enum UnificationState {
// BasicBlock-local accesses to variables are appropriately unified with each other.
LocallyUnified,
// Unification has been performed globally.
GloballyUnified
};
// Describes how reference counts in the graph behave.
enum RefCountState {
// Everything has refCount() == 1.
EverythingIsLive,
// Set after DCE has run.
ExactRefCount
};
enum OperandSpeculationMode { AutomaticOperandSpeculation, ManualOperandSpeculation };
enum ProofStatus { NeedsCheck, IsProved };
inline bool isProved(ProofStatus proofStatus)
{
ASSERT(proofStatus == IsProved || proofStatus == NeedsCheck);
return proofStatus == IsProved;
}
inline ProofStatus proofStatusForIsProved(bool isProved)
{
return isProved ? IsProved : NeedsCheck;
}
enum KillStatus { DoesNotKill, DoesKill };
inline bool doesKill(KillStatus killStatus)
{
ASSERT(killStatus == DoesNotKill || killStatus == DoesKill);
return killStatus == DoesKill;
}
inline KillStatus killStatusForDoesKill(bool doesKill)
{
return doesKill ? DoesKill : DoesNotKill;
}
enum class PlanStage {
Initial,
AfterFixup
};
// If possible, this will acquire a lock to make sure that if multiple threads
// start crashing at the same time, you get coherent dump output. Use this only
// when you're forcing a crash with diagnostics.
void startCrashing();
JS_EXPORT_PRIVATE bool isCrashing();
struct NodeAndIndex {
NodeAndIndex()
: node(nullptr)
, index(UINT_MAX)
{
}
NodeAndIndex(Node* node, unsigned index)
: node(node)
, index(index)
{
ASSERT(!node == (index == UINT_MAX));
}
bool operator!() const
{
return !node;
}
Node* node;
unsigned index;
};
// A less-than operator for strings that is useful for generating string switches. Sorts by <
// relation on characters. Ensures that if a is a prefix of b, then a < b.
bool stringLessThan(StringImpl& a, StringImpl& b);
} } // namespace JSC::DFG
namespace WTF {
void printInternal(PrintStream&, JSC::DFG::OptimizationFixpointState);
void printInternal(PrintStream&, JSC::DFG::GraphForm);
void printInternal(PrintStream&, JSC::DFG::UnificationState);
void printInternal(PrintStream&, JSC::DFG::RefCountState);
void printInternal(PrintStream&, JSC::DFG::ProofStatus);
} // namespace WTF
#endif // ENABLE(DFG_JIT)
namespace JSC { namespace DFG {
// Put things here that must be defined even if ENABLE(DFG_JIT) is false.
enum CapabilityLevel {
CannotCompile,
CanCompile,
CanCompileAndInline,
CapabilityLevelNotSet
};
inline bool canCompile(CapabilityLevel level)
{
switch (level) {
case CanCompile:
case CanCompileAndInline:
return true;
default:
return false;
}
}
inline bool canInline(CapabilityLevel level)
{
switch (level) {
case CanCompileAndInline:
return true;
default:
return false;
}
}
inline CapabilityLevel leastUpperBound(CapabilityLevel a, CapabilityLevel b)
{
switch (a) {
case CannotCompile:
return CannotCompile;
case CanCompile:
switch (b) {
case CanCompile:
case CanCompileAndInline:
return CanCompile;
default:
return CannotCompile;
}
case CanCompileAndInline:
return b;
case CapabilityLevelNotSet:
ASSERT_NOT_REACHED();
return CannotCompile;
}
ASSERT_NOT_REACHED();
return CannotCompile;
}
// Unconditionally disable DFG disassembly support if the DFG is not compiled in.
inline bool shouldDumpDisassembly(JITCompilationMode mode = JITCompilationMode::DFG)
{
#if ENABLE(DFG_JIT)
return Options::dumpDisassembly() || Options::dumpDFGDisassembly() || (isFTL(mode) && Options::dumpFTLDisassembly());
#else
UNUSED_PARAM(mode);
return false;
#endif
}
} } // namespace JSC::DFG
namespace WTF {
void printInternal(PrintStream&, JSC::DFG::CapabilityLevel);
} // namespace WTF