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09d0cfee8d
Now we can discern the types of values in heap boxes at runtime! Closure reference captures are a common way of creating reference cycles, so this provides some basic infrastructure for detecting those someday. A closure capture descriptor has the following: - The number of captures. - The number of sources of metadata reachable from the closure. This is important for substituting generics at runtime since we can't know precisely what will get captured until we observe a closure. - The number of types in the NecessaryBindings structure. This is a holding tank in a closure for sources of metadata that can't be gotten from the captured values themselves. - The metadata source map, a list of pairs, for each source of metadata for every generic argument needed to perform substitution at runtime. Key: The typeref for the generic parameter visible from the closure in the Swift source. Value: The metadata source, which describes how to crawl the heap from the closure to get to the metadata for that generic argument. - A list of typerefs for the captured values themselves. Follow-up: IRGen tests for various capture scenarios, which will include MetadataSource encoding tests. rdar://problem/24989531
106 lines
2.5 KiB
C++
106 lines
2.5 KiB
C++
//===--- MetadataSource.cpp - Swift Metadata Sources for Reflection -------===//
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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 - 2016 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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#include "swift/Reflection/MetadataSource.h"
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#include <sstream>
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using namespace swift;
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using namespace reflection;
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class PrintMetadataSource
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: public MetadataSourceVisitor<PrintMetadataSource, void> {
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std::ostream &OS;
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unsigned Indent;
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std::ostream &indent(unsigned Amount) {
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for (unsigned i = 0; i < Amount; ++i)
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OS << ' ';
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return OS;
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}
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std::ostream &printHeader(std::string Name) {
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indent(Indent) << '(' << Name;
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return OS;
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}
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template<typename T>
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std::ostream &printField(std::string name, const T &value) {
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if (!name.empty())
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OS << " " << name << "=" << value;
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else
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OS << " " << value;
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return OS;
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}
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void printRec(const MetadataSource *MS) {
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OS << "\n";
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Indent += 2;
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visit(MS);
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Indent -= 2;
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}
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void closeForm() {
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OS << ')';
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}
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public:
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PrintMetadataSource(std::ostream &OS, unsigned Indent)
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: OS(OS), Indent(Indent) {}
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void
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visitClosureBindingMetadataSource(const ClosureBindingMetadataSource *CB) {
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printHeader("closure-binding");
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printField("index", CB->getIndex());
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closeForm();
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}
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void
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visitReferenceCaptureMetadataSource(const ReferenceCaptureMetadataSource *RC){
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printHeader("reference-capture");
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printField("index", RC->getIndex());
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closeForm();
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}
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void
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visitMetadataCaptureMetadataSource(const MetadataCaptureMetadataSource *MC){
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printHeader("metadata-capture");
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printField("index", MC->getIndex());
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closeForm();
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}
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void
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visitGenericArgumentMetadataSource(const GenericArgumentMetadataSource *GA) {
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printHeader("generic-argument");
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printField("index", GA->getIndex());
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printRec(GA->getSource());
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closeForm();
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}
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void
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visitParentMetadataSource(const ParentMetadataSource *P) {
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printHeader("parent-of");
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printRec(P->getChild());
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closeForm();
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}
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};
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void MetadataSource::dump() const {
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dump(std::cerr, 0);
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}
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void MetadataSource::dump(std::ostream &OS, unsigned Indent) const {
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PrintMetadataSource(OS, Indent).visit(this);
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OS << std::endl;
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}
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