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f716bb2c3e
This will let us eventually do tagged pointer optimization for small error values. We don't take advantage of this in IRGen yet, but we can take advantage of it in the dynamic cast code in a few places, so it gets exercised, and doing this now will let us backward-deploy the optimization when we do implement it in the future.
120 lines
3.8 KiB
C++
120 lines
3.8 KiB
C++
//===--- ErrorObject.cpp - Recoverable error object -----------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This implements the object representation of the standard ErrorType protocol
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// type, which represents recoverable errors in the language. This
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// implementation is used when ObjC interop is disabled; the ObjC-interoperable
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// version is implemented in ErrorObject.mm.
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//
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//===----------------------------------------------------------------------===//
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#include <stdio.h>
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#include "Debug.h"
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#include "ErrorObject.h"
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#include "Private.h"
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#if !SWIFT_OBJC_INTEROP
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using namespace swift;
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/// Determine the size and alignment of an ErrorType box containing the given
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/// type.
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static std::pair<size_t, size_t>
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_getErrorAllocatedSizeAndAlignmentMask(const Metadata *type) {
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// The value is tail-allocated after the SwiftError record with the
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// appropriate alignment.
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auto vw = type->getValueWitnesses();
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size_t size = sizeof(SwiftError);
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unsigned valueAlignMask = vw->getAlignmentMask();
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size = (size + valueAlignMask) & ~(size_t)valueAlignMask;
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size += vw->getSize();
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size_t alignMask = (alignof(SwiftError) - 1) | valueAlignMask;
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return {size, alignMask};
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}
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/// Destructor for an ErrorType box.
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static void _destroyErrorObject(HeapObject *obj) {
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auto error = static_cast<SwiftError *>(obj);
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// Destroy the value inside.
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auto type = error->type;
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type->vw_destroy(error->getValue());
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// Deallocate the buffer.
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auto sizeAndAlign = _getErrorAllocatedSizeAndAlignmentMask(type);
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swift_deallocObject(obj, sizeAndAlign.first, sizeAndAlign.second);
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}
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/// Heap metadata for ErrorType boxes.
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static const FullMetadata<HeapMetadata> ErrorTypeMetadata{
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HeapMetadataHeader{{_destroyErrorObject}, {&_TWVBo}},
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Metadata{MetadataKind::ErrorObject},
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};
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BoxPair::Return
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swift::swift_allocError(const swift::Metadata *type,
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const swift::WitnessTable *errorConformance,
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OpaqueValue *initialValue,
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bool isTake) {
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auto sizeAndAlign = _getErrorAllocatedSizeAndAlignmentMask(type);
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auto allocated = swift_allocObject(&ErrorTypeMetadata,
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sizeAndAlign.first, sizeAndAlign.second);
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auto error = reinterpret_cast<SwiftError*>(allocated);
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error->type = type;
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error->errorConformance = errorConformance;
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// If an initial value was given, copy or take it in.
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auto valuePtr = error->getValue();
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if (initialValue) {
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if (isTake)
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type->vw_initializeWithTake(valuePtr, initialValue);
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else
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type->vw_initializeWithCopy(valuePtr, initialValue);
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}
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return BoxPair{allocated, valuePtr};
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}
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void
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swift::swift_deallocError(SwiftError *error, const Metadata *type) {
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auto sizeAndAlign = _getErrorAllocatedSizeAndAlignmentMask(type);
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swift_deallocObject(error, sizeAndAlign.first, sizeAndAlign.second);
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}
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void
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swift::swift_getErrorValue(const SwiftError *errorObject,
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void **scratch,
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ErrorValueResult *out) {
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out->value = errorObject->getValue();
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out->type = errorObject->type;
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out->errorConformance = errorObject->errorConformance;
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}
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SwiftError *
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swift::swift_errorRetain(SwiftError *object) {
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swift_retain(object);
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return static_cast<SwiftError*>(object);
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}
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void swift::swift_errorRelease(SwiftError *object) {
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swift_release(object);
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}
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void swift::swift_willThrow(SwiftError *object) { }
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#endif
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