[turbofan]: Fix tail calls edge cases and add tests

Review URL: https://codereview.chromium.org/1245523002

Cr-Commit-Position: refs/heads/master@{#29791}

src/compiler/linkage.cc

@@ -53,6 +53,25 @@ bool CallDescriptor::HasSameReturnLocationsAs(
 
 
 bool CallDescriptor::CanTailCall(const Node* node) const {
+  // Determine the number of stack parameters passed in
+  size_t stack_params = 0;
+  for (size_t i = 0; i < InputCount(); ++i) {
+    if (!GetInputLocation(i).is_register()) {
+      ++stack_params;
+    }
+  }
+  // Ensure the input linkage contains the stack parameters in the right order
+  size_t current_stack_param = 0;
+  for (size_t i = 0; i < InputCount(); ++i) {
+    if (!GetInputLocation(i).is_register()) {
+      if (GetInputLocation(i) !=
+          LinkageLocation(static_cast<int>(current_stack_param) -
+                          static_cast<int>(stack_params))) {
+        return false;
+      }
+      ++current_stack_param;
+    }
+  }
   // Tail calling is currently allowed if return locations match and all
   // parameters are either in registers or on the stack but match exactly in
   // number and content.
@@ -60,10 +79,9 @@ bool CallDescriptor::CanTailCall(const Node* node) const {
   if (!HasSameReturnLocationsAs(other)) return false;
   size_t current_input = 0;
   size_t other_input = 0;
-  size_t stack_parameter = 0;
   while (true) {
     if (other_input >= other->InputCount()) {
-      while (current_input <= InputCount()) {
+      while (current_input < InputCount()) {
         if (!GetInputLocation(current_input).is_register()) {
           return false;
         }
@@ -96,11 +114,12 @@ bool CallDescriptor::CanTailCall(const Node* node) const {
     if (input->opcode() != IrOpcode::kParameter) {
       return false;
     }
+    // Make sure that the parameter input passed through to the tail call
+    // corresponds to the correct stack slot.
     size_t param_index = ParameterIndexOf(input->op());
-    if (param_index != stack_parameter) {
+    if (param_index != current_input - 1) {
       return false;
     }
-    ++stack_parameter;
     ++current_input;
     ++other_input;
   }

test/unittests/compiler/linkage-tail-call-unittest.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 "src/compiler/common-operator.h"
+#include "src/compiler/graph.h"
+#include "src/compiler/linkage.h"
+#include "src/compiler/node.h"
+#include "test/unittests/test-utils.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+namespace {
+
+MachineType kMachineTypes[] = {kMachAnyTagged, kMachAnyTagged, kMachAnyTagged,
+                               kMachAnyTagged, kMachAnyTagged, kMachAnyTagged,
+                               kMachAnyTagged, kMachAnyTagged};
+}
+
+class LinkageTailCall : public TestWithZone {
+ protected:
+  CallDescriptor* NewStandardCallDescriptor(LocationSignature* locations) {
+    DCHECK(arraysize(kMachineTypes) >=
+           locations->return_count() + locations->parameter_count());
+    MachineSignature* types = new (zone()) MachineSignature(
+        locations->return_count(), locations->parameter_count(), kMachineTypes);
+    return new (zone())
+        CallDescriptor(CallDescriptor::kCallCodeObject, kMachAnyTagged,
+                       LinkageLocation::AnyRegister(),
+                       types,                     // machine_sig
+                       locations,                 // location_sig
+                       0,                         // js_parameter_count
+                       Operator::kNoProperties,   // properties
+                       0,                         // callee-saved
+                       0,                         // callee-saved fp
+                       CallDescriptor::kNoFlags,  // flags,
+                       "");
+  }
+
+  LinkageLocation StackLocation(int loc) { return LinkageLocation(-loc); }
+
+  LinkageLocation RegisterLocation(int loc) { return LinkageLocation(loc); }
+};
+
+
+TEST_F(LinkageTailCall, EmptyToEmpty) {
+  LocationSignature locations(0, 0, nullptr);
+  CallDescriptor* desc = NewStandardCallDescriptor(&locations);
+  CommonOperatorBuilder common(zone());
+  const Operator* op = common.Call(desc);
+  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
+  EXPECT_TRUE(desc->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, SameReturn) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0)};
+  LocationSignature locations1(1, 0, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Callee
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);
+
+  CommonOperatorBuilder common(zone());
+  const Operator* op = common.Call(desc2);
+  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
+  EXPECT_TRUE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, DifferingReturn) {
+  // Caller
+  LinkageLocation location_array1[] = {RegisterLocation(0)};
+  LocationSignature locations1(1, 0, location_array1);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Callee
+  LinkageLocation location_array2[] = {RegisterLocation(1)};
+  LocationSignature locations2(1, 0, location_array2);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);
+
+  CommonOperatorBuilder common(zone());
+  const Operator* op = common.Call(desc2);
+  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
+  EXPECT_FALSE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MoreRegisterParametersCallee) {
+  // Caller
+  LinkageLocation location_array1[] = {RegisterLocation(0)};
+  LocationSignature locations1(1, 0, location_array1);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Callee
+  LinkageLocation location_array2[] = {RegisterLocation(0),
+                                       RegisterLocation(0)};
+  LocationSignature locations2(1, 1, location_array2);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);
+
+  CommonOperatorBuilder common(zone());
+  const Operator* op = common.Call(desc2);
+  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
+  EXPECT_TRUE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MoreRegisterParametersCaller) {
+  // Caller
+  LinkageLocation location_array1[] = {RegisterLocation(0),
+                                       RegisterLocation(0)};
+  LocationSignature locations1(1, 1, location_array1);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Callee
+  LinkageLocation location_array2[] = {RegisterLocation(0)};
+  LocationSignature locations2(1, 0, location_array2);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);
+
+  CommonOperatorBuilder common(zone());
+  const Operator* op = common.Call(desc2);
+  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
+  EXPECT_TRUE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MoreRegisterAndStackParametersCallee) {
+  // Caller
+  LinkageLocation location_array1[] = {RegisterLocation(0)};
+  LocationSignature locations1(1, 0, location_array1);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Callee
+  LinkageLocation location_array2[] = {RegisterLocation(0), RegisterLocation(0),
+                                       RegisterLocation(1), StackLocation(1)};
+  LocationSignature locations2(1, 3, location_array2);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);
+
+  CommonOperatorBuilder common(zone());
+  const Operator* op = common.Call(desc2);
+  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
+  EXPECT_FALSE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MoreRegisterAndStackParametersCaller) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0), RegisterLocation(0),
+                                      RegisterLocation(1), StackLocation(1)};
+  LocationSignature locations1(1, 3, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Callee
+  LinkageLocation location_array2[] = {RegisterLocation(0)};
+  LocationSignature locations2(1, 0, location_array2);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);
+
+  CommonOperatorBuilder common(zone());
+  const Operator* op = common.Call(desc2);
+  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
+  EXPECT_FALSE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MatchingStackParameters) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
+                                      StackLocation(2), StackLocation(1)};
+  LocationSignature locations1(1, 3, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Caller
+  LocationSignature locations2(1, 3, location_array);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);
+
+  CommonOperatorBuilder common(zone());
+  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
+  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
+  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
+  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
+  Node* parameters[] = {p0, p1, p2, p3};
+  const Operator* op = common.Call(desc2);
+  Node* const node =
+      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
+  EXPECT_TRUE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, NonMatchingStackParameters) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
+                                      StackLocation(2), StackLocation(1)};
+  LocationSignature locations1(1, 3, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Caller
+  LocationSignature locations2(1, 3, location_array);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);
+
+  CommonOperatorBuilder common(zone());
+  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
+  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
+  Node* p2 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
+  Node* p3 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
+  Node* parameters[] = {p0, p1, p2, p3};
+  const Operator* op = common.Call(desc2);
+  Node* const node =
+      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
+  EXPECT_FALSE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MatchingStackParametersExtraCallerRegisters) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
+                                      StackLocation(2),    StackLocation(1),
+                                      RegisterLocation(0), RegisterLocation(1)};
+  LocationSignature locations1(1, 5, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Caller
+  LocationSignature locations2(1, 3, location_array);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);
+
+  CommonOperatorBuilder common(zone());
+  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
+  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
+  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
+  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
+  Node* parameters[] = {p0, p1, p2, p3};
+  const Operator* op = common.Call(desc2);
+  Node* const node =
+      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
+  EXPECT_TRUE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MatchingStackParametersExtraCalleeRegisters) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
+                                      StackLocation(2),    StackLocation(1),
+                                      RegisterLocation(0), RegisterLocation(1)};
+  LocationSignature locations1(1, 3, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Caller
+  LocationSignature locations2(1, 5, location_array);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);
+
+  CommonOperatorBuilder common(zone());
+  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
+  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
+  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
+  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
+  Node* p4 = Node::New(zone(), 0, common.Parameter(3), 0, nullptr, false);
+  Node* parameters[] = {p0, p1, p2, p3, p4};
+  const Operator* op = common.Call(desc2);
+  Node* const node =
+      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
+  EXPECT_TRUE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MatchingStackParametersExtraCallerRegistersAndStack) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
+                                      StackLocation(2),    StackLocation(1),
+                                      RegisterLocation(0), StackLocation(4)};
+  LocationSignature locations1(1, 5, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Caller
+  LocationSignature locations2(1, 3, location_array);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);
+
+  CommonOperatorBuilder common(zone());
+  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
+  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
+  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
+  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
+  Node* p4 = Node::New(zone(), 0, common.Parameter(3), 0, nullptr, false);
+  Node* parameters[] = {p0, p1, p2, p3, p4};
+  const Operator* op = common.Call(desc2);
+  Node* const node =
+      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
+  EXPECT_FALSE(desc1->CanTailCall(node));
+}
+
+
+TEST_F(LinkageTailCall, MatchingStackParametersExtraCalleeRegistersAndStack) {
+  // Caller
+  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
+                                      StackLocation(2),    RegisterLocation(0),
+                                      RegisterLocation(1), StackLocation(4)};
+  LocationSignature locations1(1, 3, location_array);
+  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);
+
+  // Caller
+  LocationSignature locations2(1, 5, location_array);
+  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);
+
+  CommonOperatorBuilder common(zone());
+  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
+  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
+  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
+  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
+  Node* p4 = Node::New(zone(), 0, common.Parameter(3), 0, nullptr, false);
+  Node* parameters[] = {p0, p1, p2, p3, p4};
+  const Operator* op = common.Call(desc2);
+  Node* const node =
+      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
+  EXPECT_FALSE(desc1->CanTailCall(node));
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8

test/unittests/unittests.gyp

@@ -66,6 +66,7 @@
         'compiler/js-operator-unittest.cc',
         'compiler/js-typed-lowering-unittest.cc',
         'compiler/js-type-feedback-unittest.cc',
+        'compiler/linkage-tail-call-unittest.cc',
         'compiler/liveness-analyzer-unittest.cc',
         'compiler/load-elimination-unittest.cc',
         'compiler/loop-peeling-unittest.cc',