Revive stress deopt counter in turbofan

Adds the counter to x64 only.

Bug: v8:6900
Change-Id: Ia290102b38f029a0b71c40e4b00ecc5f07dfa59c
Reviewed-on: https://chromium-review.googlesource.com/704678
Commit-Queue: Michał Majewski <majeski@google.com>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48378}

src/compiler/arm/code-generator-arm.cc

@@ -2648,6 +2648,10 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   if (!branch->fallthru) __ b(flabel);  // no fallthru to flabel.
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  AssembleArchBranch(instr, branch);
+}
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ b(GetLabel(target));

src/compiler/arm64/code-generator-arm64.cc

@@ -2325,6 +2325,10 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   if (!branch->fallthru) __ B(flabel);  // no fallthru to flabel.
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  AssembleArchBranch(instr, branch);
+}
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ B(GetLabel(target));

src/compiler/code-generator.cc

@@ -504,7 +504,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleInstruction(
       branch.false_label = &continue_label;
       branch.fallthru = true;
       // Assemble architecture-specific branch.
-      AssembleArchBranch(instr, &branch);
+      AssembleArchDeoptBranch(instr, &branch);
       tasm()->bind(&continue_label);
       break;
     }

src/compiler/code-generator.h

@@ -158,6 +158,10 @@ class CodeGenerator final : public GapResolver::Assembler {
   CodeGenResult AssembleArchInstruction(Instruction* instr);
   void AssembleArchJump(RpoNumber target);
   void AssembleArchBranch(Instruction* instr, BranchInfo* branch);
+
+  // Generates special branch for deoptimization condition.
+  void AssembleArchDeoptBranch(Instruction* instr, BranchInfo* branch);
+
   void AssembleArchBoolean(Instruction* instr, FlagsCondition condition);
   void AssembleArchTrap(Instruction* instr, FlagsCondition condition);
   void AssembleArchLookupSwitch(Instruction* instr);

src/compiler/ia32/code-generator-ia32.cc

@@ -2457,6 +2457,10 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   if (!branch->fallthru) __ jmp(flabel);
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  AssembleArchBranch(instr, branch);
+}
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ jmp(GetLabel(target));

src/compiler/mips/code-generator-mips.cc

@@ -3065,6 +3065,10 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
                          branch->fallthru);
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  AssembleArchBranch(instr, branch);
+}
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ Branch(GetLabel(target));

src/compiler/mips64/code-generator-mips64.cc

@@ -3361,6 +3361,10 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
                          branch->fallthru);
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  AssembleArchBranch(instr, branch);
+}
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ Branch(GetLabel(target));

src/compiler/ppc/code-generator-ppc.cc

@@ -2110,6 +2110,10 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   if (!branch->fallthru) __ b(flabel);  // no fallthru to flabel.
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  AssembleArchBranch(instr, branch);
+}
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ b(GetLabel(target));

src/compiler/s390/code-generator-s390.cc

@@ -2522,6 +2522,11 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   if (!branch->fallthru) __ b(flabel);  // no fallthru to flabel.
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  AssembleArchBranch(instr, branch);
+}
+
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ b(GetLabel(target));
 }

src/compiler/x64/code-generator-x64.cc

@@ -2830,6 +2830,46 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   if (!branch->fallthru) __ jmp(flabel, flabel_distance);
 }
 
+void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
+                                            BranchInfo* branch) {
+  Label::Distance flabel_distance =
+      branch->fallthru ? Label::kNear : Label::kFar;
+  Label* tlabel = branch->true_label;
+  Label* flabel = branch->false_label;
+  Label nodeopt;
+  if (branch->condition == kUnorderedEqual) {
+    __ j(parity_even, flabel, flabel_distance);
+  } else if (branch->condition == kUnorderedNotEqual) {
+    __ j(parity_even, tlabel);
+  }
+  __ j(FlagsConditionToCondition(branch->condition), tlabel);
+
+  if (FLAG_deopt_every_n_times > 0) {
+    ExternalReference counter =
+        ExternalReference::stress_deopt_count(isolate());
+
+    __ pushfq();
+    __ pushq(rax);
+    __ load_rax(counter);
+    __ decl(rax);
+    __ j(not_zero, &nodeopt);
+
+    __ Set(rax, FLAG_deopt_every_n_times);
+    __ store_rax(counter);
+    __ popq(rax);
+    __ popfq();
+    __ jmp(tlabel);
+
+    __ bind(&nodeopt);
+    __ store_rax(counter);
+    __ popq(rax);
+    __ popfq();
+  }
+
+  if (!branch->fallthru) {
+    __ jmp(flabel, flabel_distance);
+  }
+}
 
 void CodeGenerator::AssembleArchJump(RpoNumber target) {
   if (!IsNextInAssemblyOrder(target)) __ jmp(GetLabel(target));

test/mjsunit/compiler/stress-deopt-count-1.js

+// Copyright 2017 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.
+
+// Flags: --allow-natives-syntax --deopt-every-n-times=0 --opt --no-always-opt
+
+// Check that --deopt-every-n-times 0 doesn't deopt
+
+function f(x) {
+  return x + 1;
+}
+
+f(0);
+%OptimizeFunctionOnNextCall(f);
+
+f(1);
+assertOptimized(f, undefined, undefined, false);
+
+f(1);
+assertOptimized(f, undefined, undefined, false);

test/mjsunit/compiler/stress-deopt-count-2.js

+// Copyright 2017 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.
+
+// Flags: --allow-natives-syntax --opt --no-always-opt --deopt-every-n-times=6
+
+// Check that stress deopt count resets correctly
+
+// Function with two deopt points
+function f(x) {
+  return x + 1;
+}
+
+f(1);
+%OptimizeFunctionOnNextCall(f);
+
+// stress_deopt_count == 6
+
+f(1);
+assertOptimized(f, undefined, undefined, false);
+
+// stress_deopt_count == 4
+
+f(1);
+assertOptimized(f, undefined, undefined, false);
+
+// stress_deopt_count == 2
+
+f(1);
+// deopt & counter reset
+assertUnoptimized(f, undefined, undefined, false);
+
+// stress_deopt_count == 6
+
+%OptimizeFunctionOnNextCall(f);
+f(1);
+assertOptimized(f, undefined, undefined, false);
+
+// stress_deopt_count == 4
+
+f(1);
+assertOptimized(f, undefined, undefined, false);
+
+// stress_deopt_count == 2
+
+f(1);
+// deopt & counter reset
+assertUnoptimized(f, undefined, undefined, false);

test/mjsunit/mjsunit.js

@@ -582,7 +582,8 @@ var failWithMessage;
     return OptimizationStatusImpl(fun, sync_opt);
   }
 
-  assertUnoptimized = function assertUnoptimized(fun, sync_opt, name_opt) {
+  assertUnoptimized = function assertUnoptimized(fun, sync_opt, name_opt,
+      skip_if_maybe_deopted = true) {
     if (sync_opt === undefined) sync_opt = "";
     var opt_status = OptimizationStatus(fun, sync_opt);
     // Tests that use assertUnoptimized() do not make sense if --always-opt
@@ -590,7 +591,8 @@ var failWithMessage;
     assertFalse((opt_status & V8OptimizationStatus.kAlwaysOptimize) !== 0,
                 "test does not make sense with --always-opt");
     assertTrue((opt_status & V8OptimizationStatus.kIsFunction) !== 0, name_opt);
-    if ((opt_status & V8OptimizationStatus.kMaybeDeopted) !== 0) {
+    if (skip_if_maybe_deopted &&
+        (opt_status & V8OptimizationStatus.kMaybeDeopted) !== 0) {
       // When --deopt-every-n-times flag is specified it's no longer guaranteed
       // that particular function is still deoptimized, so keep running the test
       // to stress test the deoptimizer.
@@ -599,7 +601,8 @@ var failWithMessage;
     assertFalse((opt_status & V8OptimizationStatus.kOptimized) !== 0, name_opt);
   }
 
-  assertOptimized = function assertOptimized(fun, sync_opt, name_opt) {
+  assertOptimized = function assertOptimized(fun, sync_opt, name_opt,
+      skip_if_maybe_deopted = true) {
     if (sync_opt === undefined) sync_opt = "";
     var opt_status = OptimizationStatus(fun, sync_opt);
     // Tests that use assertOptimized() do not make sense if --no-opt
@@ -607,7 +610,8 @@ var failWithMessage;
     assertFalse((opt_status & V8OptimizationStatus.kNeverOptimize) !== 0,
                 "test does not make sense with --no-opt");
     assertTrue((opt_status & V8OptimizationStatus.kIsFunction) !== 0, name_opt);
-    if ((opt_status & V8OptimizationStatus.kMaybeDeopted) !== 0) {
+    if (skip_if_maybe_deopted &&
+        (opt_status & V8OptimizationStatus.kMaybeDeopted) !== 0) {
       // When --deopt-every-n-times flag is specified it's no longer guaranteed
       // that particular function is still optimized, so keep running the test
       // to stress test the deoptimizer.

test/mjsunit/mjsunit.status

@@ -657,4 +657,10 @@
     'mjsunit-assertion-error' : [SKIP],
 }], # no_harness
 
+##############################################################################
+['arch != x64 or deopt_fuzzer', {
+    # Skip stress-deopt-count tests since it's in x64 only
+    'compiler/stress-deopt-count-*': [SKIP],
+}], # arch != x64 or deopt_fuzzer
+
 ]