CbC/CbC_llvm: clang/lib/Parse/ParseInit.cpp comparison

comparison clang/lib/Parse/ParseInit.cpp @ 150:1d019706d866

LLVM10

author	anatofuz
date	Thu, 13 Feb 2020 15:10:13 +0900
parents
children	2e18cbf3894f

comparison

equal deleted inserted replaced

-:c2174574ed3a
+:1d019706d866
+//===--- ParseInit.cpp - Initializer Parsing ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements initializer parsing as specified by C99 6.7.8.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/Basic/TokenKinds.h"
+#include "clang/Parse/ParseDiagnostic.h"
+#include "clang/Parse/Parser.h"
+#include "clang/Parse/RAIIObjectsForParser.h"
+#include "clang/Sema/Designator.h"
+#include "clang/Sema/Ownership.h"
+#include "clang/Sema/Scope.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallString.h"
+using namespace clang;
+/// MayBeDesignationStart - Return true if the current token might be the start
+/// of a designator.  If we can tell it is impossible that it is a designator,
+/// return false.
+bool Parser::MayBeDesignationStart() {
+switch (Tok.getKind()) {
+default:
+return false;
+case tok::period:      // designator: '.' identifier
+return true;
+case tok::l_square: {  // designator: array-designator
+if (!PP.getLangOpts().CPlusPlus11)
+return true;
+// C++11 lambda expressions and C99 designators can be ambiguous all the
+// way through the closing ']' and to the next character. Handle the easy
+// cases here, and fall back to tentative parsing if those fail.
+switch (PP.LookAhead(0).getKind()) {
+case tok::equal:
+case tok::ellipsis:
+case tok::r_square:
+// Definitely starts a lambda expression.
+return false;
+case tok::amp:
+case tok::kw_this:
+case tok::star:
+case tok::identifier:
+// We have to do additional analysis, because these could be the
+// start of a constant expression or a lambda capture list.
+break;
+default:
+// Anything not mentioned above cannot occur following a '[' in a
+// lambda expression.
+return true;
+}
+// Handle the complicated case below.
+break;
+}
+case tok::identifier:  // designation: identifier ':'
+return PP.LookAhead(0).is(tok::colon);
+}
+// Parse up to (at most) the token after the closing ']' to determine
+// whether this is a C99 designator or a lambda.
+RevertingTentativeParsingAction Tentative(*this);
+LambdaIntroducer Intro;
+LambdaIntroducerTentativeParse ParseResult;
+if (ParseLambdaIntroducer(Intro, &ParseResult)) {
+// Hit and diagnosed an error in a lambda.
+// FIXME: Tell the caller this happened so they can recover.
+return true;
+}
+switch (ParseResult) {
+case LambdaIntroducerTentativeParse::Success:
+case LambdaIntroducerTentativeParse::Incomplete:
+// Might be a lambda-expression. Keep looking.
+// FIXME: If our tentative parse was not incomplete, parse the lambda from
+// here rather than throwing away then reparsing the LambdaIntroducer.
+break;
+case LambdaIntroducerTentativeParse::MessageSend:
+case LambdaIntroducerTentativeParse::Invalid:
+// Can't be a lambda-expression. Treat it as a designator.
+// FIXME: Should we disambiguate against a message-send?
+return true;
+}
+// Once we hit the closing square bracket, we look at the next
+// token. If it's an '=', this is a designator. Otherwise, it's a
+// lambda expression. This decision favors lambdas over the older
+// GNU designator syntax, which allows one to omit the '=', but is
+// consistent with GCC.
+return Tok.is(tok::equal);
+}
+static void CheckArrayDesignatorSyntax(Parser &P, SourceLocation Loc,
+Designation &Desig) {
+// If we have exactly one array designator, this used the GNU
+// 'designation: array-designator' extension, otherwise there should be no
+// designators at all!
+if (Desig.getNumDesignators() == 1 &&
+(Desig.getDesignator(0).isArrayDesignator() ||
+Desig.getDesignator(0).isArrayRangeDesignator()))
+P.Diag(Loc, diag::ext_gnu_missing_equal_designator);
+else if (Desig.getNumDesignators() > 0)
+P.Diag(Loc, diag::err_expected_equal_designator);
+}
+/// ParseInitializerWithPotentialDesignator - Parse the 'initializer' production
+/// checking to see if the token stream starts with a designator.
+///
+/// C99:
+///
+///       designation:
+///         designator-list '='
+/// [GNU]   array-designator
+/// [GNU]   identifier ':'
+///
+///       designator-list:
+///         designator
+///         designator-list designator
+///
+///       designator:
+///         array-designator
+///         '.' identifier
+///
+///       array-designator:
+///         '[' constant-expression ']'
+/// [GNU]   '[' constant-expression '...' constant-expression ']'
+///
+/// C++20:
+///
+///       designated-initializer-list:
+///         designated-initializer-clause
+///         designated-initializer-list ',' designated-initializer-clause
+///
+///       designated-initializer-clause:
+///         designator brace-or-equal-initializer
+///
+///       designator:
+///         '.' identifier
+///
+/// We allow the C99 syntax extensions in C++20, but do not allow the C++20
+/// extension (a braced-init-list after the designator with no '=') in C99.
+///
+/// NOTE: [OBC] allows '[ objc-receiver objc-message-args ]' as an
+/// initializer (because it is an expression).  We need to consider this case
+/// when parsing array designators.
+///
+/// \p CodeCompleteCB is called with Designation parsed so far.
+ExprResult Parser::ParseInitializerWithPotentialDesignator(
+llvm::function_ref<void(const Designation &)> CodeCompleteCB) {
+// If this is the old-style GNU extension:
+//   designation ::= identifier ':'
+// Handle it as a field designator.  Otherwise, this must be the start of a
+// normal expression.
+if (Tok.is(tok::identifier)) {
+const IdentifierInfo *FieldName = Tok.getIdentifierInfo();
+SmallString<256> NewSyntax;
+llvm::raw_svector_ostream(NewSyntax) << '.' << FieldName->getName()
+<< " = ";
+SourceLocation NameLoc = ConsumeToken(); // Eat the identifier.
+assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!");
+SourceLocation ColonLoc = ConsumeToken();
+Diag(NameLoc, diag::ext_gnu_old_style_field_designator)
+<< FixItHint::CreateReplacement(SourceRange(NameLoc, ColonLoc),
+NewSyntax);
+Designation D;
+D.AddDesignator(Designator::getField(FieldName, SourceLocation(), NameLoc));
+return Actions.ActOnDesignatedInitializer(D, ColonLoc, true,
+ParseInitializer());
+}
+// Desig - This is initialized when we see our first designator.  We may have
+// an objc message send with no designator, so we don't want to create this
+// eagerly.
+Designation Desig;
+// Parse each designator in the designator list until we find an initializer.
+while (Tok.is(tok::period) || Tok.is(tok::l_square)) {
+if (Tok.is(tok::period)) {
+// designator: '.' identifier
+SourceLocation DotLoc = ConsumeToken();
+if (Tok.is(tok::code_completion)) {
+CodeCompleteCB(Desig);
+cutOffParsing();
+return ExprError();
+}
+if (Tok.isNot(tok::identifier)) {
+Diag(Tok.getLocation(), diag::err_expected_field_designator);
+return ExprError();
+}
+Desig.AddDesignator(Designator::getField(Tok.getIdentifierInfo(), DotLoc,
+Tok.getLocation()));
+ConsumeToken(); // Eat the identifier.
+continue;
+}
+// We must have either an array designator now or an objc message send.
+assert(Tok.is(tok::l_square) && "Unexpected token!");
+// Handle the two forms of array designator:
+//   array-designator: '[' constant-expression ']'
+//   array-designator: '[' constant-expression '...' constant-expression ']'
+//
+// Also, we have to handle the case where the expression after the
+// designator an an objc message send: '[' objc-message-expr ']'.
+// Interesting cases are:
+//   [foo bar]         -> objc message send
+//   [foo]             -> array designator
+//   [foo ... bar]     -> array designator
+//   [4][foo bar]      -> obsolete GNU designation with objc message send.
+//
+// We do not need to check for an expression starting with [[ here. If it
+// contains an Objective-C message send, then it is not an ill-formed
+// attribute. If it is a lambda-expression within an array-designator, then
+// it will be rejected because a constant-expression cannot begin with a
+// lambda-expression.
+InMessageExpressionRAIIObject InMessage(*this, true);
+BalancedDelimiterTracker T(*this, tok::l_square);
+T.consumeOpen();
+SourceLocation StartLoc = T.getOpenLocation();
+ExprResult Idx;
+// If Objective-C is enabled and this is a typename (class message
+// send) or send to 'super', parse this as a message send
+// expression.  We handle C++ and C separately, since C++ requires
+// much more complicated parsing.
+if  (getLangOpts().ObjC && getLangOpts().CPlusPlus) {
+// Send to 'super'.
+if (Tok.is(tok::identifier) && Tok.getIdentifierInfo() == Ident_super &&
+NextToken().isNot(tok::period) &&
+getCurScope()->isInObjcMethodScope()) {
+CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
+return ParseAssignmentExprWithObjCMessageExprStart(
+StartLoc, ConsumeToken(), nullptr, nullptr);
+}
+// Parse the receiver, which is either a type or an expression.
+bool IsExpr;
+void *TypeOrExpr;
+if (ParseObjCXXMessageReceiver(IsExpr, TypeOrExpr)) {
+SkipUntil(tok::r_square, StopAtSemi);
+return ExprError();
+}
+// If the receiver was a type, we have a class message; parse
+// the rest of it.
+if (!IsExpr) {
+CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
+return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
+SourceLocation(),
+ParsedType::getFromOpaquePtr(TypeOrExpr),
+nullptr);
+}
+// If the receiver was an expression, we still don't know
+// whether we have a message send or an array designator; just
+// adopt the expression for further analysis below.
+// FIXME: potentially-potentially evaluated expression above?
+Idx = ExprResult(static_cast<Expr*>(TypeOrExpr));
+} else if (getLangOpts().ObjC && Tok.is(tok::identifier)) {
+IdentifierInfo *II = Tok.getIdentifierInfo();
+SourceLocation IILoc = Tok.getLocation();
+ParsedType ReceiverType;
+// Three cases. This is a message send to a type: [type foo]
+// This is a message send to super:  [super foo]
+// This is a message sent to an expr:  [super.bar foo]
+switch (Actions.getObjCMessageKind(
+getCurScope(), II, IILoc, II == Ident_super,
+NextToken().is(tok::period), ReceiverType)) {
+case Sema::ObjCSuperMessage:
+CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
+return ParseAssignmentExprWithObjCMessageExprStart(
+StartLoc, ConsumeToken(), nullptr, nullptr);
+case Sema::ObjCClassMessage:
+CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
+ConsumeToken(); // the identifier
+if (!ReceiverType) {
+SkipUntil(tok::r_square, StopAtSemi);
+return ExprError();
+}
+// Parse type arguments and protocol qualifiers.
+if (Tok.is(tok::less)) {
+SourceLocation NewEndLoc;
+TypeResult NewReceiverType
+= parseObjCTypeArgsAndProtocolQualifiers(IILoc, ReceiverType,
+/*consumeLastToken=*/true,
+NewEndLoc);
+if (!NewReceiverType.isUsable()) {
+SkipUntil(tok::r_square, StopAtSemi);
+return ExprError();
+}
+ReceiverType = NewReceiverType.get();
+}
+return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
+SourceLocation(),
+ReceiverType,
+nullptr);
+case Sema::ObjCInstanceMessage:
+// Fall through; we'll just parse the expression and
+// (possibly) treat this like an Objective-C message send
+// later.
+break;
+}
+}
+// Parse the index expression, if we haven't already gotten one
+// above (which can only happen in Objective-C++).
+// Note that we parse this as an assignment expression, not a constant
+// expression (allowing *=, =, etc) to handle the objc case.  Sema needs
+// to validate that the expression is a constant.
+// FIXME: We also need to tell Sema that we're in a
+// potentially-potentially evaluated context.
+if (!Idx.get()) {
+Idx = ParseAssignmentExpression();
+if (Idx.isInvalid()) {
+SkipUntil(tok::r_square, StopAtSemi);
+return Idx;
+}
+}
+// Given an expression, we could either have a designator (if the next
+// tokens are '...' or ']' or an objc message send.  If this is an objc
+// message send, handle it now.  An objc-message send is the start of
+// an assignment-expression production.
+if (getLangOpts().ObjC && Tok.isNot(tok::ellipsis) &&
+Tok.isNot(tok::r_square)) {
+CheckArrayDesignatorSyntax(*this, Tok.getLocation(), Desig);
+return ParseAssignmentExprWithObjCMessageExprStart(
+StartLoc, SourceLocation(), nullptr, Idx.get());
+}
+// If this is a normal array designator, remember it.
+if (Tok.isNot(tok::ellipsis)) {
+Desig.AddDesignator(Designator::getArray(Idx.get(), StartLoc));
+} else {
+// Handle the gnu array range extension.
+Diag(Tok, diag::ext_gnu_array_range);
+SourceLocation EllipsisLoc = ConsumeToken();
+ExprResult RHS(ParseConstantExpression());
+if (RHS.isInvalid()) {
+SkipUntil(tok::r_square, StopAtSemi);
+return RHS;
+}
+Desig.AddDesignator(Designator::getArrayRange(Idx.get(),
+RHS.get(),
+StartLoc, EllipsisLoc));
+}
+T.consumeClose();
+Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc(
+T.getCloseLocation());
+}
+// Okay, we're done with the designator sequence.  We know that there must be
+// at least one designator, because the only case we can get into this method
+// without a designator is when we have an objc message send.  That case is
+// handled and returned from above.
+assert(!Desig.empty() && "Designator is empty?");
+// Handle a normal designator sequence end, which is an equal.
+if (Tok.is(tok::equal)) {
+SourceLocation EqualLoc = ConsumeToken();
+return Actions.ActOnDesignatedInitializer(Desig, EqualLoc, false,
+ParseInitializer());
+}
+// Handle a C++20 braced designated initialization, which results in
+// direct-list-initialization of the aggregate element. We allow this as an
+// extension from C++11 onwards (when direct-list-initialization was added).
+if (Tok.is(tok::l_brace) && getLangOpts().CPlusPlus11) {
+return Actions.ActOnDesignatedInitializer(Desig, SourceLocation(), false,
+ParseBraceInitializer());
+}
+// We read some number of designators and found something that isn't an = or
+// an initializer.  If we have exactly one array designator, this
+// is the GNU 'designation: array-designator' extension.  Otherwise, it is a
+// parse error.
+if (Desig.getNumDesignators() == 1 &&
+(Desig.getDesignator(0).isArrayDesignator() ||
+Desig.getDesignator(0).isArrayRangeDesignator())) {
+Diag(Tok, diag::ext_gnu_missing_equal_designator)
+<< FixItHint::CreateInsertion(Tok.getLocation(), "= ");
+return Actions.ActOnDesignatedInitializer(Desig, Tok.getLocation(),
+true, ParseInitializer());
+}
+Diag(Tok, diag::err_expected_equal_designator);
+return ExprError();
+}
+/// ParseBraceInitializer - Called when parsing an initializer that has a
+/// leading open brace.
+///
+///       initializer: [C99 6.7.8]
+///         '{' initializer-list '}'
+///         '{' initializer-list ',' '}'
+/// [GNU]   '{' '}'
+///
+///       initializer-list:
+///         designation[opt] initializer ...[opt]
+///         initializer-list ',' designation[opt] initializer ...[opt]
+///
+ExprResult Parser::ParseBraceInitializer() {
+InMessageExpressionRAIIObject InMessage(*this, false);
+BalancedDelimiterTracker T(*this, tok::l_brace);
+T.consumeOpen();
+SourceLocation LBraceLoc = T.getOpenLocation();
+/// InitExprs - This is the actual list of expressions contained in the
+/// initializer.
+ExprVector InitExprs;
+if (Tok.is(tok::r_brace)) {
+// Empty initializers are a C++ feature and a GNU extension to C.
+if (!getLangOpts().CPlusPlus)
+Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
+// Match the '}'.
+return Actions.ActOnInitList(LBraceLoc, None, ConsumeBrace());
+}
+// Enter an appropriate expression evaluation context for an initializer list.
+EnterExpressionEvaluationContext EnterContext(
+Actions, EnterExpressionEvaluationContext::InitList);
+bool InitExprsOk = true;
+auto CodeCompleteDesignation = [&](const Designation &D) {
+Actions.CodeCompleteDesignator(PreferredType.get(T.getOpenLocation()),
+InitExprs, D);
+};
+while (1) {
+// Handle Microsoft __if_exists/if_not_exists if necessary.
+if (getLangOpts().MicrosoftExt && (Tok.is(tok::kw___if_exists) ||
+Tok.is(tok::kw___if_not_exists))) {
+if (ParseMicrosoftIfExistsBraceInitializer(InitExprs, InitExprsOk)) {
+if (Tok.isNot(tok::comma)) break;
+ConsumeToken();
+}
+if (Tok.is(tok::r_brace)) break;
+continue;
+}
+// Parse: designation[opt] initializer
+// If we know that this cannot be a designation, just parse the nested
+// initializer directly.
+ExprResult SubElt;
+if (MayBeDesignationStart())
+SubElt = ParseInitializerWithPotentialDesignator(CodeCompleteDesignation);
+else
+SubElt = ParseInitializer();
+if (Tok.is(tok::ellipsis))
+SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken());
+SubElt = Actions.CorrectDelayedTyposInExpr(SubElt.get());
+// If we couldn't parse the subelement, bail out.
+if (SubElt.isUsable()) {
+InitExprs.push_back(SubElt.get());
+} else {
+InitExprsOk = false;
+// We have two ways to try to recover from this error: if the code looks
+// grammatically ok (i.e. we have a comma coming up) try to continue
+// parsing the rest of the initializer.  This allows us to emit
+// diagnostics for later elements that we find.  If we don't see a comma,
+// assume there is a parse error, and just skip to recover.
+// FIXME: This comment doesn't sound right. If there is a r_brace
+// immediately, it can't be an error, since there is no other way of
+// leaving this loop except through this if.
+if (Tok.isNot(tok::comma)) {
+SkipUntil(tok::r_brace, StopBeforeMatch);
+break;
+}
+}
+// If we don't have a comma continued list, we're done.
+if (Tok.isNot(tok::comma)) break;
+// TODO: save comma locations if some client cares.
+ConsumeToken();
+// Handle trailing comma.
+if (Tok.is(tok::r_brace)) break;
+}
+bool closed = !T.consumeClose();
+if (InitExprsOk && closed)
+return Actions.ActOnInitList(LBraceLoc, InitExprs,
+T.getCloseLocation());
+return ExprError(); // an error occurred.
+}
+// Return true if a comma (or closing brace) is necessary after the
+// __if_exists/if_not_exists statement.
+bool Parser::ParseMicrosoftIfExistsBraceInitializer(ExprVector &InitExprs,
+bool &InitExprsOk) {
+bool trailingComma = false;
+IfExistsCondition Result;
+if (ParseMicrosoftIfExistsCondition(Result))
+return false;
+BalancedDelimiterTracker Braces(*this, tok::l_brace);
+if (Braces.consumeOpen()) {
+Diag(Tok, diag::err_expected) << tok::l_brace;
+return false;
+}
+switch (Result.Behavior) {
+case IEB_Parse:
+// Parse the declarations below.
+break;
+case IEB_Dependent:
+Diag(Result.KeywordLoc, diag::warn_microsoft_dependent_exists)
+<< Result.IsIfExists;
+// Fall through to skip.
+LLVM_FALLTHROUGH;
+case IEB_Skip:
+Braces.skipToEnd();
+return false;
+}
+auto CodeCompleteDesignation = [&](const Designation &D) {
+Actions.CodeCompleteDesignator(PreferredType.get(Braces.getOpenLocation()),
+InitExprs, D);
+};
+while (!isEofOrEom()) {
+trailingComma = false;
+// If we know that this cannot be a designation, just parse the nested
+// initializer directly.
+ExprResult SubElt;
+if (MayBeDesignationStart())
+SubElt = ParseInitializerWithPotentialDesignator(CodeCompleteDesignation);
+else
+SubElt = ParseInitializer();
+if (Tok.is(tok::ellipsis))
+SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken());
+// If we couldn't parse the subelement, bail out.
+if (!SubElt.isInvalid())
+InitExprs.push_back(SubElt.get());
+else
+InitExprsOk = false;
+if (Tok.is(tok::comma)) {
+ConsumeToken();
+trailingComma = true;
+}
+if (Tok.is(tok::r_brace))
+break;
+}
+Braces.consumeClose();
+return !trailingComma;
+}

Mercurial > hg > CbC > CbC_llvm

comparison clang/lib/Parse/ParseInit.cpp @ 150:1d019706d866