Adding support for multiple returns in compiled functions.

test/cctest/compiler/test-multiple-return.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 <cmath>
+#include <functional>
+#include <limits>
+
+#include "src/assembler.h"
+#include "src/base/bits.h"
+#include "src/base/utils/random-number-generator.h"
+#include "src/codegen.h"
+#include "src/compiler.h"
+#include "src/compiler/linkage.h"
+#include "src/macro-assembler.h"
+#include "test/cctest/cctest.h"
+#include "test/cctest/compiler/codegen-tester.h"
+#include "test/cctest/compiler/value-helper.h"
+
+
+using namespace v8::base;
+using namespace v8::internal;
+using namespace v8::internal::compiler;
+
+
+namespace {
+
+CallDescriptor* GetCallDescriptor(Zone* zone, int return_count,
+                                  int param_count) {
+  MachineSignature::Builder msig(zone, return_count, param_count);
+  LocationSignature::Builder locations(zone, return_count, param_count);
+
+  // Add return location(s).
+  for (int i = 0; i < return_count; i++) {
+    msig.AddReturn(compiler::kMachInt32);
+    locations.AddReturn(LinkageLocation::ForRegister(i));

[MTBrandyberry, 2015/10/08 21:37:54]

The set of register eligible for assignment as return values here and just below
as parameters needs to be platform-specific.  This current version crashes on
PPC since register index 1 corresponds to the stack pointer.

+  }
+
+  // Add register and/or stack parameter(s).
+  for (int i = 0; i < param_count; i++) {
+    msig.AddParam(compiler::kMachInt32);
+    locations.AddParam(LinkageLocation::ForRegister(i));
+  }
+
+  const RegList kCalleeSaveRegisters = 0;
+  const RegList kCalleeSaveFPRegisters = 0;
+
+  // The target for WASM calls is always a code object.
+  MachineType target_type = compiler::kMachAnyTagged;
+  LinkageLocation target_loc = LinkageLocation::ForAnyRegister();
+  return new (zone) CallDescriptor(       // --
+      CallDescriptor::kCallCodeObject,    // kind
+      target_type,                        // target MachineType
+      target_loc,                         // target location
+      msig.Build(),                       // machine_sig
+      locations.Build(),                  // location_sig
+      0,                                  // js_parameter_count
+      compiler::Operator::kNoProperties,  // properties
+      kCalleeSaveRegisters,               // callee-saved registers
+      kCalleeSaveFPRegisters,             // callee-saved fp regs
+      CallDescriptor::kNoFlags,           // flags
+      "c-call");
+}
+}  // namespace
+
+
+TEST(ReturnThreeValues) {
+  Zone zone;
+  CallDescriptor* desc = GetCallDescriptor(&zone, 3, 2);
+  HandleAndZoneScope handles;
+  RawMachineAssembler m(handles.main_isolate(),
+                        new (handles.main_zone()) Graph(handles.main_zone()),
+                        desc, kMachPtr,
+                        InstructionSelector::SupportedMachineOperatorFlags());
+
+  Node* p0 = m.Parameter(0);
+  Node* p1 = m.Parameter(1);
+  Node* add = m.Int32Add(p0, p1);
+  Node* sub = m.Int32Sub(p0, p1);
+  Node* mul = m.Int32Mul(p0, p1);
+  m.Return(add, sub, mul);
+
+  CompilationInfo info("testing", handles.main_isolate(), handles.main_zone());
+  Handle<Code> code =
+      Pipeline::GenerateCodeForTesting(&info, desc, m.graph(), m.Export());
+#ifdef ENABLE_DISASSEMBLER
+  if (FLAG_print_code) {
+    OFStream os(stdout);
+    code->Disassemble("three_value", os);
+  }
+#endif
+
+  RawMachineAssemblerTester<int32_t> mt;
+  Node* a = mt.Int32Constant(123);
+  Node* b = mt.Int32Constant(456);
+  Node* ret3 = mt.AddNode(mt.common()->Call(desc), mt.HeapConstant(code), a, b);
+  Node* x = mt.AddNode(mt.common()->Projection(0), ret3);
+  Node* y = mt.AddNode(mt.common()->Projection(1), ret3);
+  Node* z = mt.AddNode(mt.common()->Projection(2), ret3);
+  Node* ret = mt.Int32Add(mt.Int32Add(x, y), z);
+  mt.Return(ret);
+#ifdef ENABLE_DISASSEMBLER
+  Handle<Code> code2 = mt.GetCode();
+  if (FLAG_print_code) {
+    OFStream os(stdout);
+    code2->Disassemble("three_value_call", os);
+  }
+#endif
+  CHECK_EQ((123 + 456) + (123 - 456) + (123 * 456), mt.Call());
+}