Ensure UseRegisterAtStart not used with fixed temp/return register

R=vegorov@chromium.org
BUG=chromium:201590

Review URL: https://codereview.chromium.org/13527007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14124 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-arm.cc

@@ -871,6 +871,35 @@ void LChunkBuilder::VisitInstruction(HInstruction* current) {
   LInstruction* instr = current->CompileToLithium(this);
 
   if (instr != NULL) {
+#if DEBUG
+    // Make sure that the lithium instruction has either no fixed register
+    // constraints in temps or the result OR no uses that are only used at
+    // start. If this invariant doesn't hold, the register allocator can decide
+    // to insert a split of a range immediately before the instruction due to an
+    // already allocated register needing to be used for the instruction's fixed
+    // register constraint. In this case, The register allocator won't see an
+    // interference between the split child and the use-at-start (it would if
+    // the it was just a plain use), so it is free to move the split child into
+    // the same register that is used for the use-at-start.
+    // See https://code.google.com/p/chromium/issues/detail?id=201590
+    if (!(instr->ClobbersRegisters() && instr->ClobbersDoubleRegisters())) {
+      int fixed = 0;
+      int used_at_start = 0;
+      for (UseIterator it(instr); !it.Done(); it.Advance()) {
+        LUnallocated* operand = LUnallocated::cast(it.Current());
+        if (operand->IsUsedAtStart()) ++used_at_start;
+      }
+      if (instr->Output() != NULL) {
+        if (LUnallocated::cast(instr->Output())->HasFixedPolicy()) ++fixed;
+      }
+      for (TempIterator it(instr); !it.Done(); it.Advance()) {
+        LUnallocated* operand = LUnallocated::cast(it.Current());
+        if (operand->HasFixedPolicy()) ++fixed;
+      }
+      ASSERT(fixed == 0 || used_at_start == 0);
+    }
+#endif
+
     if (FLAG_stress_pointer_maps && !instr->HasPointerMap()) {
       instr = AssignPointerMap(instr);
     }
@@ -1115,7 +1144,7 @@ LInstruction* LChunkBuilder::DoUnaryMathOperation(HUnaryMathOperation* instr) {
     LUnaryMathOperation* result = new(zone()) LUnaryMathOperation(input, temp);
     return DefineFixedDouble(result, d2);
   } else {
-    LOperand* input = UseRegisterAtStart(instr->value());
+    LOperand* input = UseRegister(instr->value());
 
     LOperand* temp = (op == kMathRound) ? FixedTemp(d3) : NULL;
     LUnaryMathOperation* result = new(zone()) LUnaryMathOperation(input, temp);
@@ -1823,11 +1852,13 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       return AssignEnvironment(DefineAsRegister(res));
     } else {
       ASSERT(to.IsInteger32());
-      LOperand* value = UseRegisterAtStart(instr->value());
+      LOperand* value = NULL;
       LInstruction* res = NULL;
       if (instr->value()->type().IsSmi()) {
+        value = UseRegisterAtStart(instr->value());
         res = DefineAsRegister(new(zone()) LSmiUntag(value, false));
       } else {
+        value = UseRegister(instr->value());
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = instr->CanTruncateToInt32() ? TempRegister()
                                                       : NULL;

src/ia32/lithium-ia32.cc

@@ -923,6 +923,35 @@ void LChunkBuilder::VisitInstruction(HInstruction* current) {
   LInstruction* instr = current->CompileToLithium(this);
 
   if (instr != NULL) {
+#if DEBUG
+    // Make sure that the lithium instruction has either no fixed register
+    // constraints in temps or the result OR no uses that are only used at
+    // start. If this invariant doesn't hold, the register allocator can decide
+    // to insert a split of a range immediately before the instruction due to an
+    // already allocated register needing to be used for the instruction's fixed
+    // register constraint. In this case, The register allocator won't see an
+    // interference between the split child and the use-at-start (it would if
+    // the it was just a plain use), so it is free to move the split child into
+    // the same register that is used for the use-at-start.
+    // See https://code.google.com/p/chromium/issues/detail?id=201590
+    if (!(instr->ClobbersRegisters() && instr->ClobbersDoubleRegisters())) {
+      int fixed = 0;
+      int used_at_start = 0;
+      for (UseIterator it(instr); !it.Done(); it.Advance()) {
+        LUnallocated* operand = LUnallocated::cast(it.Current());
+        if (operand->IsUsedAtStart()) ++used_at_start;
+      }
+      if (instr->Output() != NULL) {
+        if (LUnallocated::cast(instr->Output())->HasFixedPolicy()) ++fixed;
+      }
+      for (TempIterator it(instr); !it.Done(); it.Advance()) {
+        LUnallocated* operand = LUnallocated::cast(it.Current());
+        if (operand->HasFixedPolicy()) ++fixed;
+      }
+      ASSERT(fixed == 0 || used_at_start == 0);
+    }
+#endif
+
     if (FLAG_stress_pointer_maps && !instr->HasPointerMap()) {
       instr = AssignPointerMap(instr);
     }
@@ -1182,16 +1211,20 @@ LInstruction* LChunkBuilder::DoUnaryMathOperation(HUnaryMathOperation* instr) {
                                                                   input);
     return MarkAsCall(DefineFixedDouble(result, xmm1), instr);
   } else {
-    LOperand* input = UseRegisterAtStart(instr->value());
     LOperand* context = UseAny(instr->context());  // Deferred use by MathAbs.
+    LOperand* input = NULL;
     if (op == kMathPowHalf) {
+      input = UseRegisterAtStart(instr->value());
       LOperand* temp = TempRegister();
       LMathPowHalf* result = new(zone()) LMathPowHalf(context, input, temp);
       return DefineSameAsFirst(result);
     } else if (op == kMathRound) {
+      input = UseRegister(instr->value());
       LOperand* temp = FixedTemp(xmm4);
       LMathRound* result = new(zone()) LMathRound(context, input, temp);
       return AssignEnvironment(DefineAsRegister(result));
+    } else {
+      input = UseRegisterAtStart(instr->value());
     }
     LUnaryMathOperation* result = new(zone()) LUnaryMathOperation(context,
                                                                   input);

src/x64/lithium-x64.cc

@@ -879,6 +879,35 @@ void LChunkBuilder::VisitInstruction(HInstruction* current) {
   LInstruction* instr = current->CompileToLithium(this);
 
   if (instr != NULL) {
+#if DEBUG
+    // Make sure that the lithium instruction has either no fixed register
+    // constraints in temps or the result OR no uses that are only used at
+    // start. If this invariant doesn't hold, the register allocator can decide
+    // to insert a split of a range immediately before the instruction due to an
+    // already allocated register needing to be used for the instruction's fixed
+    // register constraint. In this case, The register allocator won't see an
+    // interference between the split child and the use-at-start (it would if
+    // the it was just a plain use), so it is free to move the split child into
+    // the same register that is used for the use-at-start.
+    // See https://code.google.com/p/chromium/issues/detail?id=201590
+    if (!(instr->ClobbersRegisters() && instr->ClobbersDoubleRegisters())) {
+      int fixed = 0;
+      int used_at_start = 0;
+      for (UseIterator it(instr); !it.Done(); it.Advance()) {
+        LUnallocated* operand = LUnallocated::cast(it.Current());
+        if (operand->IsUsedAtStart()) ++used_at_start;
+      }
+      if (instr->Output() != NULL) {
+        if (LUnallocated::cast(instr->Output())->HasFixedPolicy()) ++fixed;
+      }
+      for (TempIterator it(instr); !it.Done(); it.Advance()) {
+        LUnallocated* operand = LUnallocated::cast(it.Current());
+        if (operand->HasFixedPolicy()) ++fixed;
+      }
+      ASSERT(fixed == 0 || used_at_start == 0);
+    }
+#endif
+
     if (FLAG_stress_pointer_maps && !instr->HasPointerMap()) {
       instr = AssignPointerMap(instr);
     }

test/mjsunit/regress/regress-201590.js

@@ -0,0 +1,66 @@
+// Copyright 2013 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.
+
+// Flags: --allow-natives-syntax
+
+var gdpRatio = 16/9;
+
+function Foo(initialX, initialY, initialScale, initialMapHeight) {
+  this.ORIGIN = { x: initialX, y: initialY };
+  this.scale = initialScale;
+  this.mapHeight = initialMapHeight;
+}
+
+Foo.prototype.bar = function (x, y, xOffset, yOffset) {
+  var tileHeight =  64 * 0.25 * this.scale,
+  tileWidth  = 128 * 0.25 * this.scale,
+  xOffset    = xOffset * 0.5 || 0,
+  yOffset    = yOffset * 0.5 || 0;
+  var xPos = ((xOffset) * gdpRatio) + this.ORIGIN.x * this.scale -
+      ((y * tileWidth ) * gdpRatio) + ((x * tileWidth ) * gdpRatio);
+  var yPos = ((yOffset) * gdpRatio) + this.ORIGIN.y * this.scale +
+      ((y * tileHeight) * gdpRatio) + ((x * tileHeight) * gdpRatio);
+  xPos = xPos - Math.round(((tileWidth) * gdpRatio)) +
+      this.mapHeight * Math.round(((tileWidth) * gdpRatio));
+  return {
+      x: Math.floor(xPos),
+      y: Math.floor(yPos)
+  };
+}
+
+var f = new Foo(10, 20, 2.5, 400);
+
+function baz() {
+  var b = f.bar(1.1, 2.2, 3.3, 4.4);
+  assertEquals(56529, b.x);
+  assertEquals(288, b.y);
+}
+
+baz();
+baz();
+%OptimizeFunctionOnNextCall(Foo.prototype.bar);
+baz();