Files
llvm-project/clang/lib/Parse/ParseInit.cpp
Douglas Gregor 0be31a2eb7 Move the "current scope" state from the Parser into Action. This
allows Sema some limited access to the current scope, which we only
use in one way: when Sema is performing some kind of declaration that
is not directly driven by the parser (e.g., due to template
instantiatio or lazy declaration of a member), we can find the Scope
associated with a DeclContext, if that DeclContext is still in the
process of being parsed. 

Use this to make the implicit declaration of special member functions
in a C++ class more "scope-less", rather than using the NULL Scope hack.

llvm-svn: 107491
2010-07-02 17:43:08 +00:00

377 lines
15 KiB
C++

//===--- ParseInit.cpp - Initializer Parsing ------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements initializer parsing as specified by C99 6.7.8.
//
//===----------------------------------------------------------------------===//
#include "clang/Parse/Designator.h"
#include "clang/Parse/Parser.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "clang/Parse/Scope.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
/// MayBeDesignationStart - Return true if this token might be the start of a
/// designator. If we can tell it is impossible that it is a designator, return
/// false.
static bool MayBeDesignationStart(tok::TokenKind K, Preprocessor &PP) {
switch (K) {
default: return false;
case tok::period: // designator: '.' identifier
case tok::l_square: // designator: array-designator
return true;
case tok::identifier: // designation: identifier ':'
return PP.LookAhead(0).is(tok::colon);
}
}
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.
///
/// 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 ']'
///
/// 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.
///
Parser::OwningExprResult Parser::ParseInitializerWithPotentialDesignator() {
// 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();
llvm::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(Tok, diag::ext_gnu_old_style_field_designator)
<< FixItHint::CreateReplacement(SourceRange(NameLoc, ColonLoc),
NewSyntax.str());
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.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.
//
SourceLocation StartLoc = ConsumeBracket();
OwningExprResult Idx(Actions);
// 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 (getLang().ObjC1 && getLang().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(), 0,
ExprArg(Actions));
}
// Parse the receiver, which is either a type or an expression.
bool IsExpr;
void *TypeOrExpr;
if (ParseObjCXXMessageReceiver(IsExpr, TypeOrExpr)) {
SkipUntil(tok::r_square);
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(),
TypeOrExpr,
ExprArg(Actions));
}
// 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 = OwningExprResult(Actions, TypeOrExpr);
} else if (getLang().ObjC1 && Tok.is(tok::identifier)) {
IdentifierInfo *II = Tok.getIdentifierInfo();
SourceLocation IILoc = Tok.getLocation();
TypeTy *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 (Action::ObjCMessageKind Kind
= Actions.getObjCMessageKind(getCurScope(), II, IILoc,
II == Ident_super,
NextToken().is(tok::period),
ReceiverType)) {
case Action::ObjCSuperMessage:
case Action::ObjCClassMessage:
CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
if (Kind == Action::ObjCSuperMessage)
return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
ConsumeToken(),
0,
ExprArg(Actions));
ConsumeToken(); // the identifier
if (!ReceiverType) {
SkipUntil(tok::r_square);
return ExprError();
}
return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
SourceLocation(),
ReceiverType,
ExprArg(Actions));
case Action::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);
return move(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 (getLang().ObjC1 && Tok.isNot(tok::ellipsis) &&
Tok.isNot(tok::r_square)) {
CheckArrayDesignatorSyntax(*this, Tok.getLocation(), Desig);
return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
SourceLocation(),
0, move(Idx));
}
// If this is a normal array designator, remember it.
if (Tok.isNot(tok::ellipsis)) {
Desig.AddDesignator(Designator::getArray(Idx.release(), StartLoc));
} else {
// Handle the gnu array range extension.
Diag(Tok, diag::ext_gnu_array_range);
SourceLocation EllipsisLoc = ConsumeToken();
OwningExprResult RHS(ParseConstantExpression());
if (RHS.isInvalid()) {
SkipUntil(tok::r_square);
return move(RHS);
}
Desig.AddDesignator(Designator::getArrayRange(Idx.release(),
RHS.release(),
StartLoc, EllipsisLoc));
}
SourceLocation EndLoc = MatchRHSPunctuation(tok::r_square, StartLoc);
Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc(EndLoc);
}
// 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());
}
// 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
/// initializer-list ',' designation[opt] initializer
///
Parser::OwningExprResult Parser::ParseBraceInitializer() {
SourceLocation LBraceLoc = ConsumeBrace();
/// InitExprs - This is the actual list of expressions contained in the
/// initializer.
ExprVector InitExprs(Actions);
if (Tok.is(tok::r_brace)) {
// Empty initializers are a C++ feature and a GNU extension to C.
if (!getLang().CPlusPlus)
Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
// Match the '}'.
return Actions.ActOnInitList(LBraceLoc, Action::MultiExprArg(Actions),
ConsumeBrace());
}
bool InitExprsOk = true;
while (1) {
// Parse: designation[opt] initializer
// If we know that this cannot be a designation, just parse the nested
// initializer directly.
OwningExprResult SubElt(Actions);
if (MayBeDesignationStart(Tok.getKind(), PP))
SubElt = ParseInitializerWithPotentialDesignator();
else
SubElt = ParseInitializer();
// If we couldn't parse the subelement, bail out.
if (!SubElt.isInvalid()) {
InitExprs.push_back(SubElt.release());
} else {
InitExprsOk = false;
// We have two ways to try to recover from this error: if the code looks
// gramatically 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, false, true);
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;
}
if (InitExprsOk && Tok.is(tok::r_brace))
return Actions.ActOnInitList(LBraceLoc, move_arg(InitExprs),
ConsumeBrace());
// Match the '}'.
MatchRHSPunctuation(tok::r_brace, LBraceLoc);
return ExprError(); // an error occurred.
}