[Compiler] Remove unnecessary UseTurboFan function and turbo_asm flag.

These are no longer necessary since we only have one optimizing compiler.
Also avoid changing --turbo-filter when --no-opt is set, and instead
explicitly check both the FLAG_opt and FLAG_turbo_filter in 
GetOptimizedCode to check whether optimization is disabled.

BUG=v8:6408

Change-Id: I0948f788e8ff111c08022270d86c22f848da300a
Reviewed-on: https://chromium-review.googlesource.com/568484
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46648}

src/compiler.cc

@@ -266,17 +266,6 @@ void EnsureFeedbackMetadata(CompilationInfo* info) {
       info->literal()->feedback_vector_spec()));
 }
 
-bool UseTurboFan(Handle<SharedFunctionInfo> shared) {
-  // Check the enabling conditions for Turbofan.
-  // 1. "use asm" code.
-  bool is_turbofanable_asm = FLAG_turbo_asm && shared->asm_function();
-
-  // 2. Explicitly enabled by the command-line filter.
-  bool passes_turbo_filter = shared->PassesFilter(FLAG_turbo_filter);
-
-  return is_turbofanable_asm || passes_turbo_filter;
-}
-
 bool ShouldUseFullCodegen(Handle<SharedFunctionInfo> shared) {
   // Code which can't be supported by the old pipeline should use Ignition.
   if (shared->must_use_ignition()) return false;
@@ -783,6 +772,7 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
   Handle<SharedFunctionInfo> shared(function->shared(), isolate);
 
   bool ignition_osr = osr_frame && osr_frame->is_interpreted();
+  USE(ignition_osr);
   DCHECK_IMPLIES(ignition_osr, !osr_ast_id.IsNone());
   DCHECK_IMPLIES(ignition_osr, FLAG_ignition_osr);
 
@@ -837,6 +827,13 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
     return MaybeHandle<Code>();
   }
 
+  // Do not use TurboFan if optimization is disabled or function doesn't pass
+  // turbo_filter.
+  if (!FLAG_opt || !shared->PassesFilter(FLAG_turbo_filter)) {
+    info->AbortOptimization(kOptimizationDisabled);
+    return MaybeHandle<Code>();
+  }
+
   // Limit the number of times we try to optimize functions.
   const int kMaxDeoptCount =
       FLAG_deopt_every_n_times == 0 ? FLAG_max_deopt_count : 1000;
@@ -845,12 +842,6 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
     return MaybeHandle<Code>();
   }
 
-  // Do not use TurboFan if activation criteria are not met.
-  if (!UseTurboFan(shared) && !ignition_osr) {
-    info->AbortOptimization(kOptimizationDisabled);
-    return MaybeHandle<Code>();
-  }
-
   TimerEventScope<TimerEventOptimizeCode> optimize_code_timer(isolate);
   RuntimeCallTimerScope runtimeTimer(isolate, &RuntimeCallStats::OptimizeCode);
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.OptimizeCode");

src/flag-definitions.h

@@ -427,7 +427,6 @@ DEFINE_BOOL(trace_turbo_trimming, false, "trace TurboFan's graph trimmer")
 DEFINE_BOOL(trace_turbo_jt, false, "trace TurboFan's jump threading")
 DEFINE_BOOL(trace_turbo_ceq, false, "trace TurboFan's control equivalence")
 DEFINE_BOOL(trace_turbo_loop, false, "trace TurboFan's loop optimizations")
-DEFINE_BOOL(turbo_asm, true, "enable TurboFan for asm.js code")
 DEFINE_BOOL(turbo_verify, DEBUG_BOOL, "verify TurboFan graphs at each phase")
 DEFINE_STRING(turbo_verify_machine_graph, nullptr,
               "verify TurboFan machine graph before instruction selection")

src/v8.cc

@@ -66,11 +66,6 @@ void V8::InitializeOncePerProcessImpl() {
     FLAG_max_semi_space_size = 1;
   }
 
-  if (!FLAG_opt && strcmp(FLAG_turbo_filter, "*") == 0) {
-    const char* filter_flag = "--turbo-filter=~";
-    FlagList::SetFlagsFromString(filter_flag, StrLength(filter_flag));
-  }
-
   base::OS::Initialize(FLAG_random_seed, FLAG_hard_abort, FLAG_gc_fake_mmap);
 
   Isolate::InitializeOncePerProcess();

test/cctest/test-api.cc

@@ -25356,11 +25356,11 @@ TEST(StringConcatOverflow) {
 
 
 TEST(TurboAsmDisablesNeuter) {
+  i::FLAG_opt = true;
   i::FLAG_allow_natives_syntax = true;
   v8::V8::Initialize();
   v8::HandleScope scope(CcTest::isolate());
   LocalContext context;
-  bool should_be_neuterable = !i::FLAG_turbo_asm;
   const char* load =
       "function Module(stdlib, foreign, heap) {"
       "  'use asm';"
@@ -25375,7 +25375,7 @@ TEST(TurboAsmDisablesNeuter) {
       "buffer";
 
   v8::Local<v8::ArrayBuffer> result = CompileRun(load).As<v8::ArrayBuffer>();
-  CHECK_EQ(should_be_neuterable, result->IsNeuterable());
+  CHECK(!result->IsNeuterable());
 
   const char* store =
       "function Module(stdlib, foreign, heap) {"
@@ -25391,7 +25391,7 @@ TEST(TurboAsmDisablesNeuter) {
       "buffer";
 
   result = CompileRun(store).As<v8::ArrayBuffer>();
-  CHECK_EQ(should_be_neuterable, result->IsNeuterable());
+  CHECK(!result->IsNeuterable());
 }
 
 

test/cctest/test-profile-generator.cc

@@ -695,6 +695,7 @@ TEST(LineNumber) {
 TEST(BailoutReason) {
   i::FLAG_allow_natives_syntax = true;
   i::FLAG_always_opt = false;
+  i::FLAG_opt = true;
   v8::HandleScope scope(CcTest::isolate());
   v8::Local<v8::Context> env = CcTest::NewContext(PROFILER_EXTENSION);
   v8::Context::Scope context_scope(env);

test/mjsunit/compiler/regress-4413-1.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --allow-natives-syntax --turbo-asm
+// Flags: --allow-natives-syntax
 
 var foo = (function(stdlib) {
   "use asm";

test/mjsunit/compiler/regress-445732.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --allow-natives-syntax --turbo-asm
+// Flags: --allow-natives-syntax
 
 "use asm";