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

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