[vm] Native effects

Adds a way to express native effects in Dart expressions in kernel.

This CL adds a `void _nativeEffect(Object)` to `dart:internal`.
The semantics of `_nativeEffect` are to not execute its arguments and
return `null`.

This CL uses this `_nativeEffect` to make sure that we never execute
the struct constructor invocations used to simulate the native behavior
of FFI trampolines.

Closes: https://github.com/dart-lang/sdk/issues/45607

TEST=tests/ffi(_2)/native_effect_test.dart

Change-Id: Ie06de145e49f8b1cae9e148c2d5d97d5cd8e6878
Cq-Include-Trybots: luci.dart.try:vm-precomp-ffi-qemu-linux-release-arm-try,vm-ffi-android-debug-arm64-try,vm-kernel-precomp-asan-linux-release-x64-try,vm-kernel-precomp-dwarf-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-obfuscate-linux-release-x64-try,analyzer-analysis-server-linux-try,analyzer-linux-release-try,dart-sdk-linux-try,vm-kernel-reload-rollback-linux-debug-x64-try,vm-kernel-reload-linux-debug-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/194421
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Daco Harkes <dacoharkes@google.com>
This commit is contained in:
Daco Harkes 2021-04-09 16:45:13 +00:00 committed by commit-bot@chromium.org
parent ea50eeb4be
commit 189c36b82a
11 changed files with 158 additions and 45 deletions

View file

@ -203,6 +203,7 @@ class FfiTransformer extends Transformer {
final Class listClass;
final Class typeClass;
final Procedure unsafeCastMethod;
final Procedure nativeEffectMethod;
final Class typedDataClass;
final Procedure typedDataBufferGetter;
final Procedure typedDataOffsetInBytesGetter;
@ -294,6 +295,8 @@ class FfiTransformer extends Transformer {
typeClass = coreTypes.typeClass,
unsafeCastMethod =
index.getTopLevelMember('dart:_internal', 'unsafeCast'),
nativeEffectMethod =
index.getTopLevelMember('dart:_internal', '_nativeEffect'),
typedDataClass = index.getClass('dart:typed_data', 'TypedData'),
typedDataBufferGetter =
index.getMember('dart:typed_data', 'TypedData', 'get:buffer'),

View file

@ -387,29 +387,29 @@ class _FfiUseSiteTransformer extends FfiTransformer {
}
/// Prevents the struct from being tree-shaken in TFA by invoking its
/// constructor in a let expression.
///
/// TFA does not recognize this as dead code, only the VM does.
/// TODO(http://dartbug.com/45607): Wrap with `_nativeEffect` to make the
/// intent of this code clear.
/// constructor in a `_nativeEffect` expression.
Expression _invokeStructConstructor(
Expression nestedExpression, Class structClass) {
final constructor = structClass.constructors
Expression nestedExpression, Class compositeClass) {
final constructor = compositeClass.constructors
.firstWhere((c) => c.name == Name("#fromTypedDataBase"));
return Let(
VariableDeclaration.forValue(
ConstructorInvocation(
constructor,
Arguments([
StaticInvocation(
uint8ListFactory,
Arguments([
ConstantExpression(IntConstant(1)),
]))
..fileOffset = nestedExpression.fileOffset,
]))
..fileOffset = nestedExpression.fileOffset,
type: InterfaceType(structClass, Nullability.nonNullable)),
return BlockExpression(
Block([
ExpressionStatement(StaticInvocation(
nativeEffectMethod,
Arguments([
ConstructorInvocation(
constructor,
Arguments([
StaticInvocation(
uint8ListFactory,
Arguments([
ConstantExpression(IntConstant(1)),
]))
..fileOffset = nestedExpression.fileOffset,
]))
..fileOffset = nestedExpression.fileOffset
])))
]),
nestedExpression)
..fileOffset = nestedExpression.fileOffset;
}

View file

@ -65,13 +65,17 @@ static method main() → void {
}
static method testLookupFunctionReturn() → void {
final ffi::DynamicLibrary* dylib = [@vm.inferred-type.metadata=dart.ffi::DynamicLibrary?] ffi::DynamicLibrary::executable();
final () →* self::Struct1* function1 = let final self::Struct1 #t1 = new self::Struct1::#fromTypedDataBase([@vm.inferred-type.metadata=dart.typed_data::_Uint8List] typ::Uint8List::•(#C18)) in ffi::_asFunctionInternal<() →* self::Struct1*, () →* self::Struct1*>([@vm.direct-call.metadata=dart.ffi::DynamicLibrary.lookup??] [@vm.inferred-type.metadata=dart.ffi::Pointer? (skip check)] dylib.{ffi::DynamicLibrary::lookup}<ffi::NativeFunction<() →* self::Struct1*>*>("function1"));
final () →* self::Struct1* function1 = block {
_in::_nativeEffect(new self::Struct1::#fromTypedDataBase([@vm.inferred-type.metadata=dart.typed_data::_Uint8List] typ::Uint8List::•(#C18)));
} =>ffi::_asFunctionInternal<() →* self::Struct1*, () →* self::Struct1*>([@vm.direct-call.metadata=dart.ffi::DynamicLibrary.lookup??] [@vm.inferred-type.metadata=dart.ffi::Pointer? (skip check)] dylib.{ffi::DynamicLibrary::lookup}<ffi::NativeFunction<() →* self::Struct1*>*>("function1"));
final self::Struct1* struct1 = [@vm.call-site-attributes.metadata=receiverType:#lib::Struct1* Function()*] function1.call();
core::print(struct1);
}
static method testAsFunctionReturn() → void {
final ffi::Pointer<ffi::NativeFunction<() →* self::Struct2*>*>* pointer = [@vm.inferred-type.metadata=dart.ffi::Pointer?] ffi::Pointer::fromAddress<ffi::NativeFunction<() →* self::Struct2*>*>(3735928559);
final () →* self::Struct2* function2 = let final self::Struct2 #t2 = new self::Struct2::#fromTypedDataBase([@vm.inferred-type.metadata=dart.typed_data::_Uint8List] typ::Uint8List::•(#C18)) in ffi::_asFunctionInternal<() →* self::Struct2*, () →* self::Struct2*>(pointer);
final () →* self::Struct2* function2 = block {
_in::_nativeEffect(new self::Struct2::#fromTypedDataBase([@vm.inferred-type.metadata=dart.typed_data::_Uint8List] typ::Uint8List::•(#C18)));
} =>ffi::_asFunctionInternal<() →* self::Struct2*, () →* self::Struct2*>(pointer);
final self::Struct2* struct2 = [@vm.call-site-attributes.metadata=receiverType:#lib::Struct2* Function()*] function2.call();
core::print(struct2);
}
@ -79,7 +83,9 @@ static method testAsFunctionReturn() → void {
return 42;
}
static method testFromFunctionArgument() → void {
final ffi::Pointer<ffi::NativeFunction<(self::Struct3*) →* ffi::Int32*>*>* pointer = let final self::Struct3 #t3 = new self::Struct3::#fromTypedDataBase([@vm.inferred-type.metadata=dart.typed_data::_Uint8List] typ::Uint8List::•(#C18)) in [@vm.inferred-type.metadata=dart.ffi::Pointer?] self::_#ffiCallback0;
final ffi::Pointer<ffi::NativeFunction<(self::Struct3*) →* ffi::Int32*>*>* pointer = block {
_in::_nativeEffect(new self::Struct3::#fromTypedDataBase([@vm.inferred-type.metadata=dart.typed_data::_Uint8List] typ::Uint8List::•(#C18)));
} =>[@vm.inferred-type.metadata=dart.ffi::Pointer?] self::_#ffiCallback0;
core::print(pointer);
}
static method testLookupFunctionArgument() → void {

View file

@ -279,6 +279,10 @@ DEFINE_NATIVE_ENTRY(Internal_unsafeCast, 0, 1) {
return arguments->NativeArgAt(0);
}
DEFINE_NATIVE_ENTRY(Internal_nativeEffect, 0, 1) {
UNREACHABLE();
}
DEFINE_NATIVE_ENTRY(Internal_reachabilityFence, 0, 1) {
UNREACHABLE();
}

View file

@ -333,6 +333,7 @@ namespace dart {
V(GrowableList_setLength, 2) \
V(GrowableList_setData, 2) \
V(Internal_unsafeCast, 1) \
V(Internal_nativeEffect, 1) \
V(Internal_reachabilityFence, 1) \
V(Internal_collectAllGarbage, 0) \
V(Internal_makeListFixedLength, 1) \

View file

@ -2643,7 +2643,7 @@ Fragment StreamingFlowGraphBuilder::BuildStaticSet(TokenPosition* p) {
}
Fragment StreamingFlowGraphBuilder::BuildMethodInvocation(TokenPosition* p) {
const intptr_t offset = ReaderOffset() - 1; // Include the tag.
const intptr_t offset = ReaderOffset() - 1; // Include the tag.
const uint8_t flags = ReadFlags(); // read flags.
const bool is_invariant = (flags & kMethodInvocationFlagInvariant) != 0;
@ -3007,7 +3007,9 @@ Fragment StreamingFlowGraphBuilder::BuildStaticInvocation(TokenPosition* p) {
}
const auto recognized_kind = target.recognized_kind();
if (recognized_kind == MethodRecognizer::kFfiAsFunctionInternal) {
if (recognized_kind == MethodRecognizer::kNativeEffect) {
return BuildNativeEffect();
} else if (recognized_kind == MethodRecognizer::kFfiAsFunctionInternal) {
return BuildFfiAsFunctionInternal();
} else if (CompilerState::Current().is_aot() &&
recognized_kind == MethodRecognizer::kFfiNativeCallbackFunction) {
@ -5018,20 +5020,42 @@ Fragment StreamingFlowGraphBuilder::BuildFunctionNode(
return instructions;
}
Fragment StreamingFlowGraphBuilder::BuildNativeEffect() {
const intptr_t argc = ReadUInt(); // Read argument count.
ASSERT(argc == 1); // Native side effect to ignore.
const intptr_t list_length = ReadListLength(); // Read types list length.
ASSERT(list_length == 0);
const intptr_t positional_count =
ReadListLength(); // Read positional argument count.
ASSERT(positional_count == 1);
BuildExpression(); // Consume expression but don't save the fragment.
Pop(); // Restore the stack.
const intptr_t named_args_len =
ReadListLength(); // Skip empty named arguments.
ASSERT(named_args_len == 0);
Fragment code;
code += NullConstant(); // Return type is void.
return code;
}
Fragment StreamingFlowGraphBuilder::BuildFfiAsFunctionInternal() {
const intptr_t argc = ReadUInt(); // read argument count.
ASSERT(argc == 1); // pointer
const intptr_t list_length = ReadListLength(); // read types list length.
ASSERT(list_length == 2); // dart signature, then native signature
const intptr_t argc = ReadUInt(); // Read argument count.
ASSERT(argc == 1); // Pointer.
const intptr_t list_length = ReadListLength(); // Read types list length.
ASSERT(list_length == 2); // Dart signature, then native signature.
const TypeArguments& type_arguments =
T.BuildTypeArguments(list_length); // read types.
T.BuildTypeArguments(list_length); // Read types.
Fragment code;
const intptr_t positional_count =
ReadListLength(); // read positional argument count
ReadListLength(); // Read positional argument count.
ASSERT(positional_count == 1);
code += BuildExpression(); // build first positional argument (pointer)
code += BuildExpression(); // Build first positional argument (pointer).
const intptr_t named_args_len =
ReadListLength(); // skip (empty) named arguments list
ReadListLength(); // Skip empty named arguments list.
ASSERT(named_args_len == 0);
code += B->BuildFfiAsFunctionInternalCall(type_arguments);
return code;
@ -5044,24 +5068,24 @@ Fragment StreamingFlowGraphBuilder::BuildFfiNativeCallbackFunction() {
//
// The FE also guarantees that all three arguments are constants.
const intptr_t argc = ReadUInt(); // read argument count
ASSERT(argc == 2); // target, exceptionalReturn
const intptr_t argc = ReadUInt(); // Read argument count.
ASSERT(argc == 2); // Target, exceptionalReturn.
const intptr_t list_length = ReadListLength(); // read types list length
ASSERT(list_length == 1); // native signature
const intptr_t list_length = ReadListLength(); // Read types list length.
ASSERT(list_length == 1); // The native signature.
const TypeArguments& type_arguments =
T.BuildTypeArguments(list_length); // read types.
T.BuildTypeArguments(list_length); // Read types.
ASSERT(type_arguments.Length() == 1 && type_arguments.IsInstantiated());
const FunctionType& native_sig =
FunctionType::CheckedHandle(Z, type_arguments.TypeAt(0));
Fragment code;
const intptr_t positional_count =
ReadListLength(); // read positional argument count
ReadListLength(); // Read positional argument count.
ASSERT(positional_count == 2);
// Read target expression and extract the target function.
code += BuildExpression(); // build first positional argument (target)
code += BuildExpression(); // Build first positional argument (target).
Definition* target_def = B->Peek();
ASSERT(target_def->IsConstant());
const Closure& target_closure =
@ -5081,7 +5105,7 @@ Fragment StreamingFlowGraphBuilder::BuildFfiNativeCallbackFunction() {
code += Drop();
const intptr_t named_args_len =
ReadListLength(); // skip (empty) named arguments list
ReadListLength(); // Skip (empty) named arguments list.
ASSERT(named_args_len == 0);
const Function& result =

View file

@ -344,11 +344,14 @@ class StreamingFlowGraphBuilder : public KernelReaderHelper {
Fragment BuildFunctionNode(TokenPosition parent_position,
StringIndex name_index);
// Build build FG for '_asFunctionInternal'. Reads an Arguments from the
// Build flow graph for '_nativeEffect'.
Fragment BuildNativeEffect();
// Build FG for '_asFunctionInternal'. Reads an Arguments from the
// Kernel buffer and pushes the resulting closure.
Fragment BuildFfiAsFunctionInternal();
// Build build FG for '_nativeCallbackFunction'. Reads an Arguments from the
// Build FG for '_nativeCallbackFunction'. Reads an Arguments from the
// Kernel buffer and pushes the resulting Function object.
Fragment BuildFfiNativeCallbackFunction();

View file

@ -166,6 +166,7 @@ namespace dart {
V(::, _abi, FfiAbi, 0x7c4ab775) \
V(::, _asFunctionInternal, FfiAsFunctionInternal, 0xbbcb235a) \
V(::, _nativeCallbackFunction, FfiNativeCallbackFunction, 0x3ff5ae9c) \
V(::, _nativeEffect, NativeEffect, 0x61e00b59) \
V(::, _loadInt8, FfiLoadInt8, 0x0f04dfd6) \
V(::, _loadInt16, FfiLoadInt16, 0xec44312d) \
V(::, _loadInt32, FfiLoadInt32, 0xee223fc3) \

View file

@ -163,11 +163,16 @@ Int32List _growRegExpStack(Int32List stack) {
T unsafeCast<T>(Object? v) native "Internal_unsafeCast";
// This function can be used to keep an object alive til that point.
//
@pragma("vm:recognized", "other")
@pragma('vm:prefer-inline')
void reachabilityFence(Object object) native "Internal_reachabilityFence";
// This function can be used to encode native side effects.
//
// The function call and it's argument are removed in flow graph construction.
@pragma("vm:recognized", "other")
void _nativeEffect(Object object) native "Internal_nativeEffect";
void sendAndExit(SendPort sendPort, var message)
native "SendPortImpl_sendAndExitInternal_";

View file

@ -0,0 +1,33 @@
// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
//
// SharedObjects=ffi_test_functions
// Tests that the dart:internal _nativeEffect flow graph builder works.
import 'dart:ffi';
import "package:expect/expect.dart";
import 'dylib_utils.dart';
void main() {
testReturnStruct1ByteInt();
}
final ffiTestFunctions = dlopenPlatformSpecific("ffi_test_functions");
final returnStruct1ByteInt = ffiTestFunctions.lookupFunction<
Struct1ByteInt Function(Int8),
Struct1ByteInt Function(int)>("ReturnStruct1ByteInt");
void testReturnStruct1ByteInt() {
final result = returnStruct1ByteInt(1);
Expect.equals(1, result.a0);
}
class Struct1ByteInt extends Struct {
@Int8()
external int a0;
}

View file

@ -0,0 +1,33 @@
// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
//
// SharedObjects=ffi_test_functions
// Tests that the dart:internal _nativeEffect flow graph builder works.
import 'dart:ffi';
import "package:expect/expect.dart";
import 'dylib_utils.dart';
void main() {
testReturnStruct1ByteInt();
}
final ffiTestFunctions = dlopenPlatformSpecific("ffi_test_functions");
final returnStruct1ByteInt = ffiTestFunctions.lookupFunction<
Struct1ByteInt Function(Int8),
Struct1ByteInt Function(int)>("ReturnStruct1ByteInt");
void testReturnStruct1ByteInt() {
final result = returnStruct1ByteInt(1);
Expect.equals(1, result.a0);
}
class Struct1ByteInt extends Struct {
@Int8()
int a0;
}