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Add some C++-specific comments in the parsing methods of if/switch/while/for. 

llvm-svn: 56060
This commit is contained in:
Argyrios Kyrtzidis 2008-09-10 17:38:35 +00:00
parent 4cc893bab6
commit eece3fe4fd
1 changed files with 71 additions and 0 deletions
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71
clang/lib/Parse/ParseStmt.cpp
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@ -434,6 +434,12 @@ Parser::StmtResult Parser::ParseIfStatement() {
// C99 6.8.4p3 - In C99, the if statement is a block. This is not
// the case for C90.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
//
if (C99orCXX)
EnterScope(Scope::DeclScope | Scope::ControlScope);
@ -457,6 +463,21 @@ Parser::StmtResult Parser::ParseIfStatement() {
// C99 6.8.4p3 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.4p1:
// The substatement in a selection-statement (each substatement, in the else
// form of the if statement) implicitly defines a local scope.
//
// For C++ we create a scope for the condition and a new scope for
// substatements because:
// -When the 'then' scope exits, we want the condition declaration to still be
// active for the 'else' scope too.
// -Sema will detect name clashes by considering declarations of a
// 'ControlScope' as part of its direct subscope.
// -If we wanted the condition and substatement to be in the same scope, we
// would have to notify ParseStatement not to create a new scope. It's
// simpler to let it create a new scope.
//
bool NeedsInnerScope = C99orCXX && Tok.isNot(tok::l_brace);
if (NeedsInnerScope) EnterScope(Scope::DeclScope);
@ -479,6 +500,11 @@ Parser::StmtResult Parser::ParseIfStatement() {
// there is no compound stmt. C90 does not have this clause. We only do
// this if the body isn't a compound statement to avoid push/pop in common
// cases.
//
// C++ 6.4p1:
// The substatement in a selection-statement (each substatement, in the else
// form of the if statement) implicitly defines a local scope.
//
NeedsInnerScope = C99orCXX && Tok.isNot(tok::l_brace);
if (NeedsInnerScope) EnterScope(Scope::DeclScope);
@ -532,6 +558,12 @@ Parser::StmtResult Parser::ParseSwitchStatement() {
// C99 6.8.4p3 - In C99, the switch statement is a block. This is
// not the case for C90. Start the switch scope.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
//
if (C99orCXX)
EnterScope(Scope::BreakScope | Scope::DeclScope | Scope::ControlScope);
else
@ -557,6 +589,14 @@ Parser::StmtResult Parser::ParseSwitchStatement() {
// C99 6.8.4p3 - In C99, the body of the switch statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.4p1:
// The substatement in a selection-statement (each substatement, in the else
// form of the if statement) implicitly defines a local scope.
//
// See comments in ParseIfStatement for why we create a scope for the
// condition and a new scope for substatement in C++.
//
bool NeedsInnerScope = C99orCXX && Tok.isNot(tok::l_brace);
if (NeedsInnerScope) EnterScope(Scope::DeclScope);
@ -595,6 +635,12 @@ Parser::StmtResult Parser::ParseWhileStatement() {
// C99 6.8.5p5 - In C99, the while statement is a block. This is not
// the case for C90. Start the loop scope.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
//
if (C99orCXX)
EnterScope(Scope::BreakScope | Scope::ContinueScope |
Scope::DeclScope | Scope::ControlScope);
@ -614,6 +660,14 @@ Parser::StmtResult Parser::ParseWhileStatement() {
// C99 6.8.5p5 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.5p2:
// The substatement in an iteration-statement implicitly defines a local scope
// which is entered and exited each time through the loop.
//
// See comments in ParseIfStatement for why we create a scope for the
// condition and a new scope for substatement in C++.
//
bool NeedsInnerScope = C99orCXX && Tok.isNot(tok::l_brace);
if (NeedsInnerScope) EnterScope(Scope::DeclScope);
@ -710,6 +764,15 @@ Parser::StmtResult Parser::ParseForStatement() {
// C99 6.8.5p5 - In C99, the for statement is a block. This is not
// the case for C90. Start the loop scope.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
// C++ 6.5.3p1:
// Names declared in the for-init-statement are in the same declarative-region
// as those declared in the condition.
//
if (C99orCXX)
EnterScope(Scope::BreakScope | Scope::ContinueScope |
Scope::DeclScope | Scope::ControlScope);
@ -808,6 +871,14 @@ Parser::StmtResult Parser::ParseForStatement() {
// C99 6.8.5p5 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.5p2:
// The substatement in an iteration-statement implicitly defines a local scope
// which is entered and exited each time through the loop.
//
// See comments in ParseIfStatement for why we create a scope for
// for-init-statement/condition and a new scope for substatement in C++.
//
bool NeedsInnerScope = C99orCXX && Tok.isNot(tok::l_brace);
if (NeedsInnerScope) EnterScope(Scope::DeclScope);