[x86] Faster/shorter code for stack checks.

src/compiler/x64/instruction-selector-x64.cc

 // Copyright 2014 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 <algorithm>
 
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 969 matching lines @@
   // Emit the call instruction.
   InstructionOperand* first_output =
       buffer.outputs.size() > 0 ? &buffer.outputs.front() : NULL;
   Instruction* call_instr =
       Emit(opcode, buffer.outputs.size(), first_output,
            buffer.instruction_args.size(), &buffer.instruction_args.front());
   call_instr->MarkAsCall();
 }
 
 
+namespace {
+
 // Shared routine for multiple compare operations.
-static void VisitCompare(InstructionSelector* selector, InstructionCode opcode,
-                         InstructionOperand left, InstructionOperand right,
-                         FlagsContinuation* cont) {
+void VisitCompare(InstructionSelector* selector, InstructionCode opcode,
+                  InstructionOperand left, InstructionOperand right,
+                  FlagsContinuation* cont) {
   X64OperandGenerator g(selector);
   opcode = cont->Encode(opcode);
   if (cont->IsBranch()) {
     selector->Emit(opcode, g.NoOutput(), left, right,
                    g.Label(cont->true_block()),
                    g.Label(cont->false_block()))->MarkAsControl();
   } else {
     DCHECK(cont->IsSet());
     selector->Emit(opcode, g.DefineAsRegister(cont->result()), left, right);
   }
 }
 
 
 // Shared routine for multiple compare operations.
-static void VisitCompare(InstructionSelector* selector, InstructionCode opcode,
-                         Node* left, Node* right, FlagsContinuation* cont,
-                         bool commutative) {
+void VisitCompare(InstructionSelector* selector, InstructionCode opcode,
+                  Node* left, Node* right, FlagsContinuation* cont,
+                  bool commutative) {
   X64OperandGenerator g(selector);
   if (commutative && g.CanBeBetterLeftOperand(right)) {
     std::swap(left, right);
   }
   VisitCompare(selector, opcode, g.UseRegister(left), g.Use(right), cont);
 }
 
 
 // Shared routine for multiple word compare operations.
-static void VisitWordCompare(InstructionSelector* selector, Node* node,
-                             InstructionCode opcode, FlagsContinuation* cont) {
+void VisitWordCompare(InstructionSelector* selector, Node* node,
+                      InstructionCode opcode, FlagsContinuation* cont) {
   X64OperandGenerator g(selector);
   Node* const left = node->InputAt(0);
   Node* const right = node->InputAt(1);
 
   // Match immediates on left or right side of comparison.
   if (g.CanBeImmediate(right)) {
     VisitCompare(selector, opcode, g.Use(left), g.UseImmediate(right), cont);
   } else if (g.CanBeImmediate(left)) {
     if (!node->op()->HasProperty(Operator::kCommutative)) cont->Commute();
     VisitCompare(selector, opcode, g.Use(right), g.UseImmediate(left), cont);
   } else {
     VisitCompare(selector, opcode, left, right, cont,
                  node->op()->HasProperty(Operator::kCommutative));
   }
 }
 
 
+// Shared routine for 64-bit word comparison operations.
+void VisitWord64Compare(InstructionSelector* selector, Node* node,
+                        FlagsContinuation* cont) {
+  X64OperandGenerator g(selector);
+  Int64BinopMatcher m(node);
+  if (m.left().IsLoad() && m.right().IsLoadStackPointer()) {
+    LoadMatcher<ExternalReferenceMatcher> mleft(m.left().node());
+    ExternalReference js_stack_limit =
+        ExternalReference::address_of_stack_limit(selector->isolate());
+    if (mleft.object().Is(js_stack_limit) && mleft.index().Is(0)) {
+      // Compare(Load(js_stack_limit), LoadStackPointer)
+      if (!node->op()->HasProperty(Operator::kCommutative)) cont->Commute();
+      InstructionCode opcode = cont->Encode(kX64StackCheck);
+      if (cont->IsBranch()) {
+        selector->Emit(opcode, g.NoOutput(), g.Label(cont->true_block()),
+                       g.Label(cont->false_block()))->MarkAsControl();
+      } else {
+        DCHECK(cont->IsSet());
+        selector->Emit(opcode, g.DefineAsRegister(cont->result()));
+      }
+      return;
+    }
+  }
+  VisitWordCompare(selector, node, kX64Cmp, cont);
+}
+
+
 // Shared routine for comparison with zero.
-static void VisitCompareZero(InstructionSelector* selector, Node* node,
-                             InstructionCode opcode, FlagsContinuation* cont) {
+void VisitCompareZero(InstructionSelector* selector, Node* node,
+                      InstructionCode opcode, FlagsContinuation* cont) {
   X64OperandGenerator g(selector);
   VisitCompare(selector, opcode, g.Use(node), g.TempImmediate(0), cont);
 }
 
 
 // Shared routine for multiple float64 compare operations (inputs commuted).
-static void VisitFloat64Compare(InstructionSelector* selector, Node* node,
-                                FlagsContinuation* cont) {
+void VisitFloat64Compare(InstructionSelector* selector, Node* node,
+                         FlagsContinuation* cont) {
   Node* const left = node->InputAt(0);
   Node* const right = node->InputAt(1);
   VisitCompare(selector, kSSEFloat64Cmp, right, left, cont, false);
 }
 
+}  // namespace
+
 
 void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
                                       BasicBlock* fbranch) {
   X64OperandGenerator g(this);
   Node* user = branch;
   Node* value = branch->InputAt(0);
 
   FlagsContinuation cont(kNotEqual, tbranch, fbranch);
 
   // Try to combine with comparisons against 0 by simply inverting the branch.
@@ skipping 21 matching lines @@
         cont.OverwriteAndNegateIfEqual(kSignedLessThanOrEqual);
         return VisitWordCompare(this, value, kX64Cmp32, &cont);
       case IrOpcode::kUint32LessThan:
         cont.OverwriteAndNegateIfEqual(kUnsignedLessThan);
         return VisitWordCompare(this, value, kX64Cmp32, &cont);
       case IrOpcode::kUint32LessThanOrEqual:
         cont.OverwriteAndNegateIfEqual(kUnsignedLessThanOrEqual);
         return VisitWordCompare(this, value, kX64Cmp32, &cont);
       case IrOpcode::kWord64Equal:
         cont.OverwriteAndNegateIfEqual(kEqual);
-        return VisitWordCompare(this, value, kX64Cmp, &cont);
+        return VisitWord64Compare(this, value, &cont);
       case IrOpcode::kInt64LessThan:
         cont.OverwriteAndNegateIfEqual(kSignedLessThan);
-        return VisitWordCompare(this, value, kX64Cmp, &cont);
+        return VisitWord64Compare(this, value, &cont);
       case IrOpcode::kInt64LessThanOrEqual:
         cont.OverwriteAndNegateIfEqual(kSignedLessThanOrEqual);
-        return VisitWordCompare(this, value, kX64Cmp, &cont);
+        return VisitWord64Compare(this, value, &cont);
       case IrOpcode::kUint64LessThan:
         cont.OverwriteAndNegateIfEqual(kUnsignedLessThan);
-        return VisitWordCompare(this, value, kX64Cmp, &cont);
+        return VisitWord64Compare(this, value, &cont);
       case IrOpcode::kFloat64Equal:
         cont.OverwriteAndNegateIfEqual(kUnorderedEqual);
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kFloat64LessThan:
         cont.OverwriteAndNegateIfEqual(kUnsignedGreaterThan);
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kFloat64LessThanOrEqual:
         cont.OverwriteAndNegateIfEqual(kUnsignedGreaterThanOrEqual);
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kProjection:
@@ skipping 17 matching lines @@
                 return VisitBinop(this, node, kX64Sub32, &cont);
               default:
                 break;
             }
           }
         }
         break;
       case IrOpcode::kInt32Sub:
         return VisitWordCompare(this, value, kX64Cmp32, &cont);
       case IrOpcode::kInt64Sub:
-        return VisitWordCompare(this, value, kX64Cmp, &cont);
+        return VisitWord64Compare(this, value, &cont);
       case IrOpcode::kWord32And:
         return VisitWordCompare(this, value, kX64Test32, &cont);
       case IrOpcode::kWord64And:
         return VisitWordCompare(this, value, kX64Test, &cont);
       default:
         break;
     }
   }
 
   // Branch could not be combined with a compare, emit compare against 0.
@@ skipping 141 matching lines @@
         cont.Negate();
       } else {
         break;
       }
     }
 
     // Try to combine the branch with a comparison.
     if (CanCover(user, value)) {
       switch (value->opcode()) {
         case IrOpcode::kInt64Sub:
-          return VisitWordCompare(this, value, kX64Cmp, &cont);
+          return VisitWord64Compare(this, value, &cont);
         case IrOpcode::kWord64And:
           return VisitWordCompare(this, value, kX64Test, &cont);
         default:
           break;
       }
     }
     return VisitCompareZero(this, value, kX64Cmp, &cont);
   }
-  VisitWordCompare(this, node, kX64Cmp, &cont);
+  VisitWord64Compare(this, node, &cont);
 }
 
 
 void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
   if (Node* ovf = NodeProperties::FindProjection(node, 1)) {
     FlagsContinuation cont(kOverflow, ovf);
     VisitBinop(this, node, kX64Add32, &cont);
   }
   FlagsContinuation cont;
   VisitBinop(this, node, kX64Add32, &cont);
 }
 
 
 void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
   if (Node* ovf = NodeProperties::FindProjection(node, 1)) {
     FlagsContinuation cont(kOverflow, ovf);
     return VisitBinop(this, node, kX64Sub32, &cont);
   }
   FlagsContinuation cont;
   VisitBinop(this, node, kX64Sub32, &cont);
 }
 
 
 void InstructionSelector::VisitInt64LessThan(Node* node) {
   FlagsContinuation cont(kSignedLessThan, node);
-  VisitWordCompare(this, node, kX64Cmp, &cont);
+  VisitWord64Compare(this, node, &cont);
 }
 
 
 void InstructionSelector::VisitInt64LessThanOrEqual(Node* node) {
   FlagsContinuation cont(kSignedLessThanOrEqual, node);
-  VisitWordCompare(this, node, kX64Cmp, &cont);
+  VisitWord64Compare(this, node, &cont);
 }
 
 
 void InstructionSelector::VisitUint64LessThan(Node* node) {
   FlagsContinuation cont(kUnsignedLessThan, node);
-  VisitWordCompare(this, node, kX64Cmp, &cont);
+  VisitWord64Compare(this, node, &cont);
 }
 
 
 void InstructionSelector::VisitFloat64Equal(Node* node) {
   FlagsContinuation cont(kUnorderedEqual, node);
   VisitFloat64Compare(this, node, &cont);
 }
 
 
 void InstructionSelector::VisitFloat64LessThan(Node* node) {
@@ skipping 54 matching lines @@
     flags |= MachineOperatorBuilder::kFloat64Floor |
              MachineOperatorBuilder::kFloat64Ceil |
              MachineOperatorBuilder::kFloat64RoundTruncate;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8