From: titzer <titzer@chromium.org>
Date: Thu, 30 Apr 2015 14:50:41 +0000 (-0700)
Subject: Allow TurboFan to compile more methods.
X-Git-Tag: upstream/4.7.83~2868
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b0dcf6abf2ebdeb3a430d1dc002aa304743ce618;p=platform%2Fupstream%2Fv8.git

Allow TurboFan to compile more methods.

Reorganize some bailout conditions to be after the decision to use TurboFan.

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1110573002

Cr-Commit-Position: refs/heads/master@{#28172}
---

diff --git a/src/compiler.cc b/src/compiler.cc
index 75349e9..036b8e5 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -322,33 +322,13 @@ OptimizedCompileJob::Status OptimizedCompileJob::CreateGraph() {
     return RetryOptimization(kDebuggerHasBreakPoints);
   }
 
-  // Limit the number of times we re-compile a functions with
-  // the optimizing compiler.
+  // Limit the number of times we try to optimize functions.
   const int kMaxOptCount =
       FLAG_deopt_every_n_times == 0 ? FLAG_max_opt_count : 1000;
   if (info()->opt_count() > kMaxOptCount) {
     return AbortOptimization(kOptimizedTooManyTimes);
   }
 
-  // Due to an encoding limit on LUnallocated operands in the Lithium
-  // language, we cannot optimize functions with too many formal parameters
-  // or perform on-stack replacement for function with too many
-  // stack-allocated local variables.
-  //
-  // The encoding is as a signed value, with parameters and receiver using
-  // the negative indices and locals the non-negative ones.
-  const int parameter_limit = -LUnallocated::kMinFixedSlotIndex;
-  Scope* scope = info()->scope();
-  if ((scope->num_parameters() + 1) > parameter_limit) {
-    return AbortOptimization(kTooManyParameters);
-  }
-
-  const int locals_limit = LUnallocated::kMaxFixedSlotIndex;
-  if (info()->is_osr() &&
-      scope->num_parameters() + 1 + scope->num_stack_slots() > locals_limit) {
-    return AbortOptimization(kTooManyParametersLocals);
-  }
-
   // Check the whitelist for Crankshaft.
   if (!info()->closure()->PassesFilter(FLAG_hydrogen_filter)) {
     return AbortOptimization(kHydrogenFilter);
@@ -379,6 +359,7 @@ OptimizedCompileJob::Status OptimizedCompileJob::CreateGraph() {
   if (((FLAG_turbo_asm && info()->shared_info()->asm_function()) ||
        info()->closure()->PassesFilter(FLAG_turbo_filter)) &&
       (FLAG_turbo_osr || !info()->is_osr())) {
+    // Use TurboFan for the compilation.
     if (FLAG_trace_opt) {
       OFStream os(stdout);
       os << "[compiling method " << Brief(*info()->closure())
@@ -403,8 +384,23 @@ OptimizedCompileJob::Status OptimizedCompileJob::CreateGraph() {
     }
   }
 
-  // Do not use Crankshaft if the code is intended to be serialized.
-  if (!isolate()->use_crankshaft()) return SetLastStatus(FAILED);
+  if (!isolate()->use_crankshaft()) {
+    // Crankshaft is entirely disabled.
+    return SetLastStatus(FAILED);
+  }
+
+  Scope* scope = info()->scope();
+  if (LUnallocated::TooManyParameters(scope->num_parameters())) {
+    // Crankshaft would require too many Lithium operands.
+    return AbortOptimization(kTooManyParameters);
+  }
+
+  if (info()->is_osr() &&
+      LUnallocated::TooManyParametersOrStackSlots(scope->num_parameters(),
+                                                  scope->num_stack_slots())) {
+    // Crankshaft would require too many Lithium operands.
+    return AbortOptimization(kTooManyParametersLocals);
+  }
 
   if (scope->HasIllegalRedeclaration()) {
     // Crankshaft cannot handle illegal redeclarations.
diff --git a/src/lithium.h b/src/lithium.h
index 895b194..f586882 100644
--- a/src/lithium.h
+++ b/src/lithium.h
@@ -252,6 +252,17 @@ class LUnallocated : public LOperand {
     DCHECK(basic_policy() == EXTENDED_POLICY);
     return LifetimeField::decode(value_) == USED_AT_START;
   }
+
+  static bool TooManyParameters(int num_parameters) {
+    const int parameter_limit = -LUnallocated::kMinFixedSlotIndex;
+    return num_parameters + 1 > parameter_limit;
+  }
+
+  static bool TooManyParametersOrStackSlots(int num_parameters,
+                                            int num_stack_slots) {
+    const int locals_limit = LUnallocated::kMaxFixedSlotIndex;
+    return num_parameters + 1 + num_stack_slots > locals_limit;
+  }
 };
 
 
diff --git a/test/mjsunit/mjsunit.status b/test/mjsunit/mjsunit.status
index ef955ea..aa5f43e 100644
--- a/test/mjsunit/mjsunit.status
+++ b/test/mjsunit/mjsunit.status
@@ -143,6 +143,8 @@
   # TODO(titzer): --always-opt incorrectly disables CrankShaft soft deopt points
   'result-table-min': [PASS, NO_VARIANTS],
   'result-table-max': [PASS, NO_VARIANTS],
+  # TODO(titzer): too slow in --turbo mode due to O(n^2) graph verification.
+  'regress/regress-1122': [PASS, NO_VARIANTS],
 
   ##############################################################################
   # Too slow in debug mode with --stress-opt mode.