WIP: prototype ffi support (from 2084663004)

src/runtime/runtime-ffi.cc

+// Copyright 2016 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/runtime/runtime-utils.h"
+
+#include "src/arguments.h"
+#include "src/assembler.h"
+#include "src/code-factory.h"
+#include "src/compilation-info.h"
+#include "src/compiler/common-operator.h"
+#include "src/compiler/ffi-compiler.h"
+#include "src/compiler/graph.h"
+#include "src/compiler/js-graph.h"
+#include "src/compiler/linkage.h"
+#include "src/compiler/machine-operator.h"
+#include "src/compiler/pipeline.h"
+
+namespace v8 {
+namespace internal {
+
+using namespace v8::internal::compiler;
+
+#define WORD_SIZE 8
+
+// TODO(mattloring): need pool per function, not global
+List<char *> mem_pool(10);
+std::map<int, void *> callback_compilations;
+
+static int StructSize(ffi::FFIStructSignature *sig) {
+  int total_size = 0;
+  int curr_alignment = 0;
+  for (size_t i = 0; i < sig->elem_count; i++) {
+    int elem_size = TypeSize(sig->elems[i].type->type);
+    // Account for padding
+    if (elem_size + curr_alignment > WORD_SIZE) {
+      total_size += WORD_SIZE - curr_alignment;
+      curr_alignment = 0;
+    }
+    curr_alignment += elem_size;
+    total_size += elem_size;
+  }
+  return total_size;
+}
+
+RUNTIME_FUNCTION(Runtime_JSStringToCharPtr) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  Handle<String> string;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, string, Object::ToString(isolate, args.at<Object>(0)));
+  int length = string->length() + 1;
+  char *str = reinterpret_cast<char *>(malloc(length));
+  snprintf(str, length, "%s", ((*string)->ToCString()).release());
+  mem_pool.Add(str);
+  // TODO(mattloring): should this be a foreign somehow? this cast is not
+  // correct
+  return reinterpret_cast<Object *>(str);
+}
+
+RUNTIME_FUNCTION(Runtime_TypedArrayToUint8Ptr) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, input_obj, 0);
+  Handle<JSTypedArray> array(JSTypedArray::cast(*input_obj));
+  uint8_t *contents =
+      reinterpret_cast<uint8_t *>(array->GetBuffer()->backing_store());
+  size_t offset = NumberToSize(array->byte_offset());
+  size_t length = NumberToSize(array->byte_length());
+  char *result = reinterpret_cast<char *>(malloc(length));
+  memcpy(result, contents + offset, length);
+  mem_pool.Add(result);
+  // TODO(mattloring): should this be a foreign somehow? this cast is not
+  // correct
+  return reinterpret_cast<Object *>(result);
+}
+
+RUNTIME_FUNCTION(Runtime_BufferToPtrNoCopy) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, input_obj, 0);
+  Handle<JSTypedArray> array(JSTypedArray::cast(*input_obj));
+  uint8_t *contents =
+      reinterpret_cast<uint8_t *>(array->GetBuffer()->backing_store());
+  size_t offset = NumberToSize(array->byte_offset());
+  // TODO(mattloring): should this be a foreign somehow? this cast is not
+  // correct
+  return reinterpret_cast<Object *>(contents + offset);
+}
+
+RUNTIME_FUNCTION(Runtime_CharPtrToJSString) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  char *str = reinterpret_cast<char *>(args[0]);
+  Handle<String> name = isolate->factory()->InternalizeUtf8String(str);
+  free(str);
+  return *name;
+}
+
+static void CallNoReturn(Isolate *isolate, Object *callable, Object *receiver,
+                         int argc, Object *argv[]) {
+  HandleScope scope(isolate);
+  Handle<Object> call_handle(callable, isolate);
+  Handle<Object> rec_handle(receiver, isolate);
+  Handle<Object> *argv_handles = new Handle<Object>[ argc ];
+  for (int i = 0; i < argc; i++) {
+    Handle<Object> arg_handle(argv[i], isolate);
+    argv_handles[i] = arg_handle;
+  }
+  // TODO(mattloring): retrieve return value instead of USE
+  USE(i::Execution::Call(isolate, call_handle, rec_handle, argc, argv_handles));
+}
+
+RUNTIME_FUNCTION(Runtime_JSFunctionToFnPtr) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(2, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, input_obj, 0);
+  Handle<JSFunction> func(JSFunction::cast(*input_obj));
+
+  if (callback_compilations[func->shared()->start_position()]) {
+    // Use cached result
+    // TODO(mattloring): cache on better property than start position
+    return reinterpret_cast<Object *>(
+        callback_compilations[func->shared()->start_position()]);
+  }
+
+  ffi::FFISignature *sig = reinterpret_cast<ffi::FFISignature *>(args[1]);
+  Zone zone(isolate->allocator(), ZONE_NAME);
+  Graph graph(&zone);
+  CommonOperatorBuilder common(&zone);
+  MachineOperatorBuilder machine(&zone);
+  JSGraph jsgraph(isolate, &graph, &common, nullptr, nullptr, &machine);
+
+  int param_count = static_cast<int>(sig->parameter_count());
+
+  MachineType invoke_reps[] = {MachineType::Pointer(), MachineType::Pointer(),
+                               MachineType::Pointer(), MachineType::Int64(),
+                               MachineType::Pointer()};
+  MachineSignature invoke_sig(0, 5, invoke_reps);
+  CallDescriptor *invoke_desc =
+      Linkage::GetSimplifiedCDescriptor(&zone, &invoke_sig);
+
+  // Unmarshall arguments coming from C going to JS
+  // Marshall value returned from JS back to C
+  Node *start =
+      graph.NewNode(common.Start(3 + param_count));  // 4 + param count
+
+  FFIGraphBuilder builder(&zone, &jsgraph);
+  builder.set_control_ptr(&start);
+  builder.set_effect_ptr(&start);
+
+  graph.SetStart(start);
+
+  Node *context = jsgraph.HeapConstant(Handle<Context>(func->context()));
+  Object **call_args = new Object *[param_count];
+  Node *call_args_node = graph.NewNode(common.ExternalConstant(
+      ExternalReference(reinterpret_cast<Address>(call_args), isolate)));
+  Node *prev_arg_translation = start;
+  if (param_count > 0) {
+    for (int i = 0; i < param_count; i++) {  // Arguments
+      Node *translated_param = builder.ToJS(
+          graph.NewNode(common.Parameter(i), start), context, sig->GetParam(i));
+      prev_arg_translation = graph.NewNode(
+          machine.Store(StoreRepresentation(
+              MachineRepresentation::kTaggedPointer, kNoWriteBarrier)),
+          call_args_node, jsgraph.Int32Constant(i), translated_param,
+          prev_arg_translation, start);
+    }
+  }
+
+  int index = 0;
+  Node **arguments = zone.NewArray<Node *>(8);
+  arguments[index++] = graph.NewNode(
+      common.Int64Constant(reinterpret_cast<int64_t>(&CallNoReturn)));
+  arguments[index++] = graph.NewNode(common.ExternalConstant(
+      ExternalReference(reinterpret_cast<Address>(isolate), isolate)));
+  arguments[index++] = jsgraph.HeapConstant(func);
+  arguments[index++] = jsgraph.UndefinedConstant();
+  arguments[index++] = jsgraph.Int64Constant(param_count);
+  arguments[index++] = call_args_node;
+  arguments[index++] = prev_arg_translation;
+  arguments[index++] = start;
+  Node *call = graph.NewNode(common.Call(invoke_desc), index, arguments);
+  Node *call_control = graph.NewNode(common.IfSuccess(), call);
+  // TODO(mattloring): retval = call;
+  Node *retval = jsgraph.Constant(42);
+  if (sig->return_count() != 0) {
+    retval = builder.FromJS(retval, context, sig->GetReturn());
+  }
+  Node *ret = graph.NewNode(common.Return(), jsgraph.Int32Constant(0), retval,
+                            call, call_control);
+  graph.SetEnd(graph.NewNode(common.End(1), ret));
+
+  MachineType *reps = builder.GetMachineTypes(sig);
+  MachineSignature mach_sig(sig->return_count(), param_count, reps);
+
+  CallDescriptor *desc = Linkage::GetSimplifiedCDescriptor(&zone, &mach_sig);
+
+  Code::Flags flags = Code::ComputeFlags(Code::STUB);
+
+  CompilationInfo info(ArrayVector("js-to-native-cb"), jsgraph.isolate(), &zone,
+                       flags);
+  Handle<Code> code = Pipeline::GenerateCodeForTesting(&info, desc, &graph);
+  callback_compilations[func->shared()->start_position()] = code->entry();
+  // TODO(mattloring): should this be a foreign somehow? this cast is not
+  // correct
+  return reinterpret_cast<Object *>(code->entry());
+}
+
+RUNTIME_FUNCTION(Runtime_JSObjectToStructPtr) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(2, args.length());
+  Handle<JSObject> obj(JSObject::cast(args[0]));
+  ffi::FFIStructSignature *sig =
+      reinterpret_cast<ffi::FFIStructSignature *>(args[1]);
+  char *result = reinterpret_cast<char *>(malloc(StructSize(sig)));
+  char *write_pos = result;
+  int alignment = 0;
+  for (size_t i = 0; i < sig->elem_count; i++) {
+    v8::ffi::FFIStructElement elem = sig->elems[i];
+    int elem_size = TypeSize(elem.type->type);
+    Handle<String> name = isolate->factory()->InternalizeUtf8String(elem.name);
+    LookupIterator it(obj, name);
+    Handle<Object> value = Object::GetProperty(&it).ToHandleChecked();
+    if (elem_size + alignment > WORD_SIZE) {
+      memset(write_pos, 0, WORD_SIZE - alignment);
+      write_pos += (WORD_SIZE - alignment);
+      alignment = 0;
+    }
+    WriteObject(value, elem.type->type, write_pos);
+    write_pos += elem_size;
+    alignment += elem_size;
+  }
+  mem_pool.Add(result);
+  // TODO(mattloring): should this be a foreign somehow? this cast is not
+  // correct
+  return reinterpret_cast<Object *>(result);
+}
+
+RUNTIME_FUNCTION(Runtime_PointerToForeign) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  intptr_t *ptr = reinterpret_cast<intptr_t *>(args[0]);
+  Handle<Foreign> foreign =
+      isolate->factory()->NewForeign(reinterpret_cast<Address>(ptr));
+  return *foreign;
+}
+
+RUNTIME_FUNCTION(Runtime_ForeignToPointer) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  Handle<Foreign> foreign(Foreign::cast(args[0]));
+  // TODO(mattloring): should this be a foreign somehow? this cast is not
+  // correct
+  return reinterpret_cast<Object *>(foreign->foreign_address());
+}
+
+RUNTIME_FUNCTION(Runtime_ReleaseFFIMemPool) {
+  HandleScope scope(isolate);
+  for (char *addr : mem_pool) {
+    free(addr);
+  }
+  mem_pool.Clear();
+  return isolate->heap()->ToBoolean(true);
+}
+}  // namespace internal
+}  // namespace v8