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//===----------- SyntaxParsingContext.h -==============----------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_PARSE_SYNTAXPARSINGCONTEXT_H
#define SWIFT_PARSE_SYNTAXPARSINGCONTEXT_H
#include "llvm/ADT/PointerUnion.h"
#include "swift/Basic/SourceLoc.h"
#include "swift/Parse/ParsedRawSyntaxNode.h"
#include "swift/Parse/ParsedRawSyntaxRecorder.h"
namespace swift {
using namespace swift::syntax;
class ParsedSyntax;
class ParsedTokenSyntax;
struct ParsedTrivia;
class SourceFile;
enum class tok;
class Token;
class DiagnosticEngine;
namespace syntax {
enum class SyntaxKind;
}
enum class SyntaxContextKind {
Decl,
Stmt,
Expr,
Type,
Pattern,
Syntax,
};
enum class SyntaxNodeCreationKind {
/// This is for \c SyntaxParsingContext to collect the syntax data and create
/// a 'recorded' ParsedRawSyntaxNode object, which would be a result of
/// passing the index data to the \c SyntaxParseActions implementation.
Recorded,
/// This is for \c SyntaxParsingContext to collect the syntax data and create
/// a 'deferred' ParsedRawSyntaxNode object, which captures the data for a
/// \c SyntaxParseActions invocation to occur later.
///
/// This is intended to be used for when it's not clear what will be the final
/// syntax node in the current parsing context.
Deferred,
};
constexpr size_t SyntaxAlignInBits = 3;
/// RAII object which receive RawSyntax parts. On destruction, this constructs
/// a specified syntax node from received parts and propagate it to the parent
/// context.
///
/// e.g.
/// parseExprParen() {
/// SyntaxParsingContext LocalCtxt(SyntaxKind::ParenExpr, SyntaxContext);
/// consumeToken(tok::l_paren) // In consumeToken(), a RawTokenSyntax is
/// // added to the context.
/// parseExpr(); // On returning from parseExpr(), a Expr Syntax node is
/// // created and added to the context.
/// consumeToken(tok::r_paren)
/// // Now the context holds { '(' Expr ')' }.
/// // From these parts, it creates ParenExpr node and add it to the parent.
/// }
class alignas(1 << SyntaxAlignInBits) SyntaxParsingContext {
public:
/// The shared data for all syntax parsing contexts with the same root.
/// This should be accessible from the root context only.
struct alignas(1 << SyntaxAlignInBits) RootContextData {
// The source file under parsing.
SourceFile &SF;
// Where to issue diagnostics.
DiagnosticEngine &Diags;
SourceManager &SourceMgr;
unsigned BufferID;
// Storage for Collected parts.
std::vector<ParsedRawSyntaxNode> Storage;
ParsedRawSyntaxRecorder Recorder;
llvm::BumpPtrAllocator ScratchAlloc;
RootContextData(SourceFile &SF, DiagnosticEngine &Diags,
SourceManager &SourceMgr, unsigned BufferID,
std::shared_ptr<SyntaxParseActions> spActions)
: SF(SF), Diags(Diags), SourceMgr(SourceMgr), BufferID(BufferID),
Recorder(std::move(spActions)) {}
};
private:
/// Indicates what action should be performed on the destruction of
/// SyntaxParsingContext
enum class AccumulationMode {
// Coerece the result to one of ContextKind.
// E.g. for ContextKind::Expr, passthroug if the result is CallExpr, whereas
// <UnknownExpr><SomeDecl /></UnknownDecl> for non Exprs.
CoerceKind,
// Construct a result Syntax with specified SyntaxKind.
CreateSyntax,
/// Construct a deferred raw node, to be recorded later.
DeferSyntax,
// Pass through all parts to the parent context.
Transparent,
// Discard all parts in the context.
Discard,
// The node has been found as incremental update and all parts shall be
// discarded.
SkippedForIncrementalUpdate,
// Construct SourceFile syntax to the specified SF.
Root,
// Invalid.
NotSet,
};
// When this context is a root, this points to an instance of RootContextData;
// When this context isn't a root, this points to the parent context.
const llvm::PointerUnion<RootContextData *, SyntaxParsingContext *>
RootDataOrParent;
// Reference to the
SyntaxParsingContext *&CtxtHolder;
RootContextData *RootData;
// Offet for 'Storage' this context owns from.
const size_t Offset;
// Operation on destruction.
AccumulationMode Mode = AccumulationMode::NotSet;
// Additional info depending on \c Mode.
union {
// For AccumulationMode::CreateSyntax; desired syntax node kind.
SyntaxKind SynKind;
// For AccumulationMode::CoerceKind; desired syntax node category.
SyntaxContextKind CtxtKind;
};
/// true if it's in backtracking context.
bool IsBacktracking = false;
// If false, context does nothing.
bool Enabled;
/// Create a syntax node using the tail \c N elements of collected parts and
/// replace those parts with the single result.
void createNodeInPlace(SyntaxKind Kind, size_t N,
SyntaxNodeCreationKind nodeCreateK);
ArrayRef<ParsedRawSyntaxNode> getParts() const {
return llvm::makeArrayRef(getStorage()).drop_front(Offset);
}
ParsedRawSyntaxNode makeUnknownSyntax(SyntaxKind Kind,
ArrayRef<ParsedRawSyntaxNode> Parts);
ParsedRawSyntaxNode createSyntaxAs(SyntaxKind Kind,
ArrayRef<ParsedRawSyntaxNode> Parts,
SyntaxNodeCreationKind nodeCreateK);
Optional<ParsedRawSyntaxNode> bridgeAs(SyntaxContextKind Kind,
ArrayRef<ParsedRawSyntaxNode> Parts);
public:
/// Construct root context.
SyntaxParsingContext(SyntaxParsingContext *&CtxtHolder, SourceFile &SF,
unsigned BufferID,
std::shared_ptr<SyntaxParseActions> SPActions);
/// Designated constructor for child context.
SyntaxParsingContext(SyntaxParsingContext *&CtxtHolder)
: RootDataOrParent(CtxtHolder), CtxtHolder(CtxtHolder),
RootData(CtxtHolder->RootData), Offset(RootData->Storage.size()),
IsBacktracking(CtxtHolder->IsBacktracking),
Enabled(CtxtHolder->isEnabled()) {
assert(CtxtHolder->isTopOfContextStack() &&
"SyntaxParsingContext cannot have multiple children");
assert(CtxtHolder->Mode != AccumulationMode::SkippedForIncrementalUpdate &&
"Cannot create child context for a node loaded from the cache");
CtxtHolder = this;
}
SyntaxParsingContext(SyntaxParsingContext *&CtxtHolder, SyntaxContextKind Kind)
: SyntaxParsingContext(CtxtHolder) {
setCoerceKind(Kind);
}
SyntaxParsingContext(SyntaxParsingContext *&CtxtHolder, SyntaxKind Kind)
: SyntaxParsingContext(CtxtHolder) {
setCreateSyntax(Kind);
}
~SyntaxParsingContext();
/// Try looking up if an unmodified node exists at \p LexerOffset of the same
/// kind. If a node is found, replace the node that is currently being
/// constructed by the parsing context with the found node and return the
/// number of bytes the found node took up in the original source. The lexer
/// should pretend it has read these bytes and continue from the advanced
/// offset. If nothing is found \c 0 is returned.
size_t lookupNode(size_t LexerOffset, SourceLoc Loc);
void disable() { Enabled = false; }
bool isEnabled() const { return Enabled; }
bool isRoot() const { return RootDataOrParent.is<RootContextData*>(); }
bool isTopOfContextStack() const { return this == CtxtHolder; }
SyntaxParsingContext *getParent() const {
return RootDataOrParent.get<SyntaxParsingContext*>();
}
RootContextData *getRootData() { return RootData; }
const RootContextData *getRootData() const { return RootData; }
std::vector<ParsedRawSyntaxNode> &getStorage() { return getRootData()->Storage; }
const std::vector<ParsedRawSyntaxNode> &getStorage() const {
return getRootData()->Storage;
}
const SyntaxParsingContext *getRoot() const;
ParsedRawSyntaxRecorder &getRecorder() { return getRootData()->Recorder; }
llvm::BumpPtrAllocator &getScratchAlloc() {
return getRootData()->ScratchAlloc;
}
/// Add RawSyntax to the parts.
void addRawSyntax(ParsedRawSyntaxNode Raw);
/// Add Token with Trivia to the parts.
void addToken(Token &Tok, const ParsedTrivia &LeadingTrivia,
const ParsedTrivia &TrailingTrivia);
/// Add Syntax to the parts.
void addSyntax(ParsedSyntax Node);
template<typename SyntaxNode>
llvm::Optional<SyntaxNode> popIf() {
auto &Storage = getStorage();
assert(Storage.size() > Offset);
if (SyntaxNode::kindof(Storage.back().getKind())) {
auto rawNode = std::move(Storage.back());
Storage.pop_back();
return SyntaxNode(rawNode);
}
return None;
}
ParsedTokenSyntax popToken();
/// Create a node using the tail of the collected parts. The number of parts
/// is automatically determined from \c Kind. Node: limited number of \c Kind
/// are supported. See the implementation.
void createNodeInPlace(SyntaxKind Kind,
SyntaxNodeCreationKind nodeCreateK = SyntaxNodeCreationKind::Recorded);
/// Squashing nodes from the back of the pending syntax list to a given syntax
/// collection kind. If there're no nodes that can fit into the collection kind,
/// this function does nothing. Otherwise, it creates a collection node in place
/// to contain all sequential suitable nodes from back.
void collectNodesInPlace(SyntaxKind ColletionKind,
SyntaxNodeCreationKind nodeCreateK = SyntaxNodeCreationKind::Recorded);
/// On destruction, construct a specified kind of syntax node consuming the
/// collected parts, then append it to the parent context.
void setCreateSyntax(SyntaxKind Kind) {
Mode = AccumulationMode::CreateSyntax;
SynKind = Kind;
}
/// Same as \c setCreateSyntax but create a deferred node instead of a
/// recorded one.
void setDeferSyntax(SyntaxKind Kind) {
Mode = AccumulationMode::DeferSyntax;
SynKind = Kind;
}
/// On destruction, if the parts size is 1 and it's kind of \c Kind, just
/// append it to the parent context. Otherwise, create Unknown{Kind} node from
/// the collected parts.
void setCoerceKind(SyntaxContextKind Kind) {
Mode = AccumulationMode::CoerceKind;
CtxtKind = Kind;
}
/// Move the collected parts to the tail of parent context.
void setTransparent() { Mode = AccumulationMode::Transparent; }
/// This context is a back tracking context, so we should discard collected
/// parts on this context.
void setBackTracking() {
Mode = AccumulationMode::Discard;
IsBacktracking = true;
}
bool isBacktracking() const { return IsBacktracking; }
/// Explicitly finalizing syntax tree creation.
/// This function will be called during the destroying of a root syntax
/// parsing context. However, we can explicitly call this function to get
/// the syntax tree before closing the root context.
ParsedRawSyntaxNode finalizeRoot();
/// Make a missing node corresponding to the given token kind and
/// push this node into the context. The synthesized node can help
/// the creation of valid syntax nodes.
void synthesize(tok Kind, SourceLoc Loc);
/// Dump the nodes that are in the storage stack of the SyntaxParsingContext
LLVM_ATTRIBUTE_DEPRECATED(void dumpStorage() const LLVM_ATTRIBUTE_USED,
"Only meant for use in the debugger");
};
} // namespace swift
#endif // SWIFT_SYNTAX_PARSING_CONTEXT_H