// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "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 THE COPYRIGHT
// OWNER 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.
#include "v8.h"
#include "runtime-profiler.h"
#include "assembler.h"
#include "bootstrapper.h"
#include "code-stubs.h"
#include "compilation-cache.h"
#include "execution.h"
#include "full-codegen.h"
#include "global-handles.h"
#include "isolate-inl.h"
#include "mark-compact.h"
#include "platform.h"
#include "scopeinfo.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 = 2;
// If the function optimization was disabled due to high deoptimization count,
// but the function is hot and has been seen on the stack this number of times,
// then we try to reenable optimization for this function.
static const int kProfilerTicksBeforeReenablingOptimization = 250;
// If a function does not have enough type info (according to
// FLAG_type_info_threshold), but has seen a huge number of ticks,
// optimize it as it is.
static const int kTicksWhenNotEnoughTypeInfo = 100;
// We only have one byte to store the number of ticks.
STATIC_ASSERT(kProfilerTicksBeforeOptimization < 256);
STATIC_ASSERT(kProfilerTicksBeforeReenablingOptimization < 256);
STATIC_ASSERT(kTicksWhenNotEnoughTypeInfo < 256);
// Maximum size in bytes of generate code for a function to allow OSR.
static const int kOSRCodeSizeAllowanceBase =
100 * FullCodeGenerator::kCodeSizeMultiplier;
static const int kOSRCodeSizeAllowancePerTick =
3 * FullCodeGenerator::kCodeSizeMultiplier;
// 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 kMaxSizeEarlyOpt =
5 * FullCodeGenerator::kCodeSizeMultiplier;
RuntimeProfiler::RuntimeProfiler(Isolate* isolate)
: isolate_(isolate),
any_ic_changed_(false) {
}
static void GetICCounts(Code* shared_code,
int* ic_with_type_info_count,
int* ic_total_count,
int* percentage) {
*ic_total_count = 0;
*ic_with_type_info_count = 0;
Object* raw_info = shared_code->type_feedback_info();
if (raw_info->IsTypeFeedbackInfo()) {
TypeFeedbackInfo* info = TypeFeedbackInfo::cast(raw_info);
*ic_with_type_info_count = info->ic_with_type_info_count();
*ic_total_count = info->ic_total_count();
}
*percentage = *ic_total_count > 0
? 100 * *ic_with_type_info_count / *ic_total_count
: 100;
}
void RuntimeProfiler::Optimize(JSFunction* function, const char* reason) {
ASSERT(function->IsOptimizable());
if (FLAG_trace_opt && function->PassesFilter(FLAG_hydrogen_filter)) {
PrintF("[marking ");
function->ShortPrint();
PrintF(" for recompilation, reason: %s", reason);
if (FLAG_type_info_threshold > 0) {
int typeinfo, total, percentage;
GetICCounts(function->shared()->code(), &typeinfo, &total, &percentage);
PrintF(", ICs with typeinfo: %d/%d (%d%%)", typeinfo, total, percentage);
}
PrintF("]\n");
}
if (isolate_->concurrent_recompilation_enabled() &&
!isolate_->bootstrapper()->IsActive()) {
if (isolate_->concurrent_osr_enabled() &&
isolate_->optimizing_compiler_thread()->IsQueuedForOSR(function)) {
// Do not attempt regular recompilation if we already queued this for OSR.
// TODO(yangguo): This is necessary so that we don't install optimized
// code on a function that is already optimized, since OSR and regular
// recompilation race. This goes away as soon as OSR becomes one-shot.
return;
}
ASSERT(!function->IsInRecompileQueue());
function->MarkForConcurrentRecompilation();
} else {
// The next call to the function will trigger optimization.
function->MarkForLazyRecompilation();
}
}
void RuntimeProfiler::AttemptOnStackReplacement(JSFunction* function) {
// See AlwaysFullCompiler (in compiler.cc) comment on why we need
// Debug::has_break_points().
if (!FLAG_use_osr ||
isolate_->DebuggerHasBreakPoints() ||
function->IsBuiltin()) {
return;
}
SharedFunctionInfo* shared = function->shared();
// If the code is not optimizable, don't try OSR.
if (!shared->code()->optimizable()) return;
// We are not prepared to do OSR for a function that already has an
// allocated arguments object. The optimized code would bypass it for
// arguments accesses, which is unsound. Don't try OSR.
if (shared->uses_arguments()) return;
// We're using on-stack replacement: patch the unoptimized code so that
// any back edge in any unoptimized frame will trigger on-stack
// replacement for that frame.
if (FLAG_trace_osr) {
PrintF("[OSR - patching back edges in ");
function->PrintName();
PrintF("]\n");
}
BackEdgeTable::Patch(isolate_, shared->code());
}
void RuntimeProfiler::OptimizeNow() {
HandleScope scope(isolate_);
if (isolate_->DebuggerHasBreakPoints()) return;
DisallowHeapAllocation no_gc;
// Run through the JavaScript frames and collect them. If we already
// have a sample of the function, we mark it for optimizations
// (eagerly or lazily).
int frame_count = 0;
int frame_count_limit = FLAG_frame_count;
for (JavaScriptFrameIterator it(isolate_);
frame_count++ < frame_count_limit && !it.done();
it.Advance()) {
JavaScriptFrame* frame = it.frame();
JSFunction* function = frame->function();
SharedFunctionInfo* shared = function->shared();
Code* shared_code = shared->code();
if (shared_code->kind() != Code::FUNCTION) continue;
if (function->IsInRecompileQueue()) continue;
if (FLAG_always_osr &&
shared_code->allow_osr_at_loop_nesting_level() == 0) {
// Testing mode: always try an OSR compile for every function.
for (int i = 0; i < Code::kMaxLoopNestingMarker; i++) {
// TODO(titzer): fix AttemptOnStackReplacement to avoid this dumb loop.
shared_code->set_allow_osr_at_loop_nesting_level(i);
AttemptOnStackReplacement(function);
}
// Fall through and do a normal optimized compile as well.
} else if (!frame->is_optimized() &&
(function->IsMarkedForLazyRecompilation() ||
function->IsMarkedForConcurrentRecompilation() ||
function->IsOptimized())) {
// Attempt OSR if we are still running unoptimized code even though the
// the function has long been marked or even already been optimized.
int ticks = shared_code->profiler_ticks();
int allowance = kOSRCodeSizeAllowanceBase +
ticks * kOSRCodeSizeAllowancePerTick;
if (shared_code->CodeSize() > allowance) {
if (ticks < 255) shared_code->set_profiler_ticks(ticks + 1);
} else {
int nesting = shared_code->allow_osr_at_loop_nesting_level();
if (nesting < Code::kMaxLoopNestingMarker) {
int new_nesting = nesting + 1;
shared_code->set_allow_osr_at_loop_nesting_level(new_nesting);
AttemptOnStackReplacement(function);
}
}
continue;
}
// Only record top-level code on top of the execution stack and
// avoid optimizing excessively large scripts since top-level code
// will be executed only once.
const int kMaxToplevelSourceSize = 10 * 1024;
if (shared->is_toplevel() &&
(frame_count > 1 || shared->SourceSize() > kMaxToplevelSourceSize)) {
continue;
}
// Do not record non-optimizable functions.
if (shared->optimization_disabled()) {
if (shared->deopt_count() >= FLAG_max_opt_count) {
// If optimization was disabled due to many deoptimizations,
// then check if the function is hot and try to reenable optimization.
int ticks = shared_code->profiler_ticks();
if (ticks >= kProfilerTicksBeforeReenablingOptimization) {
shared_code->set_profiler_ticks(0);
shared->TryReenableOptimization();
} else {
shared_code->set_profiler_ticks(ticks + 1);
}
}
continue;
}
if (!function->IsOptimizable()) continue;
int ticks = shared_code->profiler_ticks();
if (ticks >= kProfilerTicksBeforeOptimization) {
int typeinfo, total, percentage;
GetICCounts(shared_code, &typeinfo, &total, &percentage);
if (percentage >= FLAG_type_info_threshold) {
// If this particular function hasn't had any ICs patched for enough
// ticks, optimize it now.
Optimize(function, "hot and stable");
} else if (ticks >= kTicksWhenNotEnoughTypeInfo) {
Optimize(function, "not much type info but very hot");
} else {
shared_code->set_profiler_ticks(ticks + 1);
if (FLAG_trace_opt_verbose) {
PrintF("[not yet optimizing ");
function->PrintName();
PrintF(", not enough type info: %d/%d (%d%%)]\n",
typeinfo, total, percentage);
}
}
} else if (!any_ic_changed_ &&
shared_code->instruction_size() < kMaxSizeEarlyOpt) {
// If no IC was patched since the last tick and this function is very
// small, optimistically optimize it now.
Optimize(function, "small function");
} else {
shared_code->set_profiler_ticks(ticks + 1);
}
}
any_ic_changed_ = false;
}
} } // namespace v8::internal