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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/execution/runtime-profiler.h"
#include "src/base/platform/platform.h"
#include "src/codegen/assembler.h"
#include "src/codegen/compilation-cache.h"
#include "src/codegen/compiler.h"
#include "src/codegen/pending-optimization-table.h"
#include "src/diagnostics/code-tracer.h"
#include "src/execution/execution.h"
#include "src/execution/frames-inl.h"
#include "src/handles/global-handles.h"
#include "src/init/bootstrapper.h"
#include "src/interpreter/interpreter.h"
#include "src/tracing/trace-event.h"
namespace v8 {
namespace internal {
// Number of times a function has to be seen on the stack before it is
// optimized.
static const int kProfilerTicksBeforeOptimization = 3;
// The number of ticks required for optimizing a function increases with
// the size of the bytecode. This is in addition to the
// kProfilerTicksBeforeOptimization required for any function.
static const int kBytecodeSizeAllowancePerTick = 1100;
// Maximum size in bytes of generate code for a function to allow OSR.
static const int kOSRBytecodeSizeAllowanceBase = 119;
static const int kOSRBytecodeSizeAllowancePerTick = 44;
// Maximum size in bytes of generated code for a function to be optimized
// the very first time it is seen on the stack.
static const int kMaxBytecodeSizeForEarlyOpt = 81;
#define OPTIMIZATION_REASON_LIST(V) \
V(DoNotOptimize, "do not optimize") \
V(HotAndStable, "hot and stable") \
V(SmallFunction, "small function")
enum class OptimizationReason : uint8_t {
#define OPTIMIZATION_REASON_CONSTANTS(Constant, message) k##Constant,
OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_CONSTANTS)
#undef OPTIMIZATION_REASON_CONSTANTS
};
char const* OptimizationReasonToString(OptimizationReason reason) {
static char const* reasons[] = {
#define OPTIMIZATION_REASON_TEXTS(Constant, message) message,
OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_TEXTS)
#undef OPTIMIZATION_REASON_TEXTS
};
size_t const index = static_cast<size_t>(reason);
DCHECK_LT(index, arraysize(reasons));
return reasons[index];
}
#undef OPTIMIZATION_REASON_LIST
std::ostream& operator<<(std::ostream& os, OptimizationReason reason) {
return os << OptimizationReasonToString(reason);
}
namespace {
void TraceInOptimizationQueue(JSFunction function) {
if (FLAG_trace_opt_verbose) {
PrintF("[function ");
function.PrintName();
PrintF(" is already in optimization queue]\n");
}
}
void TraceHeuristicOptimizationDisallowed(JSFunction function) {
if (FLAG_trace_opt_verbose) {
PrintF("[function ");
function.PrintName();
PrintF(" has been marked manually for optimization]\n");
}
}
void TraceRecompile(JSFunction function, OptimizationReason reason,
CodeKind code_kind, Isolate* isolate) {
if (FLAG_trace_opt) {
CodeTracer::Scope scope(isolate->GetCodeTracer());
PrintF(scope.file(), "[marking ");
function.ShortPrint(scope.file());
PrintF(scope.file(), " for optimized recompilation, reason: %s",
OptimizationReasonToString(reason));
PrintF(scope.file(), "]\n");
}
}
} // namespace
RuntimeProfiler::RuntimeProfiler(Isolate* isolate)
: isolate_(isolate), any_ic_changed_(false) {}
void RuntimeProfiler::Optimize(JSFunction function, OptimizationReason reason,
CodeKind code_kind) {
DCHECK_NE(reason, OptimizationReason::kDoNotOptimize);
TraceRecompile(function, reason, code_kind, isolate_);
function.MarkForOptimization(ConcurrencyMode::kConcurrent);
}
void RuntimeProfiler::AttemptOnStackReplacement(UnoptimizedFrame* frame,
int loop_nesting_levels) {
JSFunction function = frame->function();
SharedFunctionInfo shared = function.shared();
if (!FLAG_use_osr || !shared.IsUserJavaScript()) {
return;
}
// If the code is not optimizable, don't try OSR.
if (shared.optimization_disabled()) return;
// We're using on-stack replacement: Store new loop nesting level in
// BytecodeArray header so that certain back edges in any interpreter frame
// for this bytecode will trigger on-stack replacement for that frame.
if (FLAG_trace_osr) {
CodeTracer::Scope scope(isolate_->GetCodeTracer());
PrintF(scope.file(), "[OSR - arming back edges in ");
function.PrintName(scope.file());
PrintF(scope.file(), "]\n");
}
DCHECK(frame->is_unoptimized());
int level = frame->GetBytecodeArray().osr_loop_nesting_level();
frame->GetBytecodeArray().set_osr_loop_nesting_level(std::min(
{level + loop_nesting_levels, AbstractCode::kMaxLoopNestingMarker}));
}
void RuntimeProfiler::MaybeOptimizeFrame(JSFunction function,
JavaScriptFrame* frame,
CodeKind code_kind) {
if (function.IsInOptimizationQueue()) {
TraceInOptimizationQueue(function);
return;
}
if (FLAG_testing_d8_test_runner &&
!PendingOptimizationTable::IsHeuristicOptimizationAllowed(isolate_,
function)) {
TraceHeuristicOptimizationDisallowed(function);
return;
}
if (function.shared().optimization_disabled()) return;
// Note: We currently do not trigger OSR compilation from TP code.
if (frame->is_unoptimized()) {
if (FLAG_always_osr) {
AttemptOnStackReplacement(UnoptimizedFrame::cast(frame),
AbstractCode::kMaxLoopNestingMarker);
// Fall through and do a normal optimized compile as well.
} else if (MaybeOSR(function, UnoptimizedFrame::cast(frame))) {
return;
}
}
OptimizationReason reason =
ShouldOptimize(function, function.shared().GetBytecodeArray(isolate_));
if (reason != OptimizationReason::kDoNotOptimize) {
Optimize(function, reason, code_kind);
}
}
bool RuntimeProfiler::MaybeOSR(JSFunction function, UnoptimizedFrame* frame) {
int ticks = function.feedback_vector().profiler_ticks();
if (function.IsMarkedForOptimization() ||
function.IsMarkedForConcurrentOptimization() ||
function.HasAvailableOptimizedCode()) {
int64_t allowance = kOSRBytecodeSizeAllowanceBase +
ticks * kOSRBytecodeSizeAllowancePerTick;
if (function.shared().GetBytecodeArray(isolate_).length() <= allowance) {
AttemptOnStackReplacement(frame);
}
return true;
}
return false;
}
namespace {
bool ShouldOptimizeAsSmallFunction(int bytecode_size, int ticks,
bool any_ic_changed,
bool active_tier_is_turboprop) {
if (any_ic_changed || bytecode_size >= kMaxBytecodeSizeForEarlyOpt)
return false;
return true;
}
} // namespace
OptimizationReason RuntimeProfiler::ShouldOptimize(JSFunction function,
BytecodeArray bytecode) {
if (function.ActiveTierIsTurbofan()) {
return OptimizationReason::kDoNotOptimize;
}
if (V8_UNLIKELY(FLAG_turboprop) && function.ActiveTierIsToptierTurboprop()) {
return OptimizationReason::kDoNotOptimize;
}
int ticks = function.feedback_vector().profiler_ticks();
bool active_tier_is_turboprop = function.ActiveTierIsMidtierTurboprop();
int ticks_for_optimization =
kProfilerTicksBeforeOptimization +
(bytecode.length() / kBytecodeSizeAllowancePerTick);
if (ticks >= ticks_for_optimization) {
return OptimizationReason::kHotAndStable;
} else if (ShouldOptimizeAsSmallFunction(bytecode.length(), ticks,
any_ic_changed_,
active_tier_is_turboprop)) {
// If no IC was patched since the last tick and this function is very
// small, optimistically optimize it now.
return OptimizationReason::kSmallFunction;
} else if (FLAG_trace_opt_verbose) {
PrintF("[not yet optimizing ");
function.PrintName();
PrintF(", not enough ticks: %d/%d and ", ticks, ticks_for_optimization);
if (any_ic_changed_) {
PrintF("ICs changed]\n");
} else {
PrintF(" too large for small function optimization: %d/%d]\n",
bytecode.length(), kMaxBytecodeSizeForEarlyOpt);
}
}
return OptimizationReason::kDoNotOptimize;
}
RuntimeProfiler::MarkCandidatesForOptimizationScope::
MarkCandidatesForOptimizationScope(RuntimeProfiler* profiler)
: handle_scope_(profiler->isolate_), profiler_(profiler) {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"),
"V8.MarkCandidatesForOptimization");
}
RuntimeProfiler::MarkCandidatesForOptimizationScope::
~MarkCandidatesForOptimizationScope() {
profiler_->any_ic_changed_ = false;
}
void RuntimeProfiler::MarkCandidatesForOptimization(JavaScriptFrame* frame) {
if (!isolate_->use_optimizer()) return;
MarkCandidatesForOptimizationScope scope(this);
JSFunction function = frame->function();
CodeKind code_kind = function.GetActiveTier();
DCHECK(function.shared().is_compiled());
DCHECK(function.shared().IsInterpreted());
DCHECK_IMPLIES(CodeKindIsOptimizedJSFunction(code_kind),
function.has_feedback_vector());
if (!function.has_feedback_vector()) return;
function.feedback_vector().SaturatingIncrementProfilerTicks();
MaybeOptimizeFrame(function, frame, code_kind);
}
void RuntimeProfiler::MarkCandidatesForOptimizationFromBytecode() {
JavaScriptFrameIterator it(isolate_);
DCHECK(it.frame()->is_unoptimized());
MarkCandidatesForOptimization(it.frame());
}
void RuntimeProfiler::MarkCandidatesForOptimizationFromCode() {
JavaScriptFrameIterator it(isolate_);
DCHECK(it.frame()->is_optimized());
MarkCandidatesForOptimization(it.frame());
}
} // namespace internal
} // namespace v8
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