return false;
in a function returning a pointer. 'false' was a null pointer constant in C++98
but is not in C++11. Punch a very small hole in the initialization rules in
C++11 mode to allow this specific case in system headers.
llvm-svn: 184395
the result of a cast-to-reference-type lifetime-extends the object to which the
reference inside the cast binds.
This requires us to look for subobject adjustments on both the inside and the
outside of the MaterializeTemporaryExpr when looking for a temporary to
lifetime-extend (which we also need for core issue 616, and possibly 1213).
llvm-svn: 184024
Introduce CXXStdInitializerListExpr node, representing the implicit
construction of a std::initializer_list<T> object from its underlying array.
The AST representation of such an expression goes from an InitListExpr with a
flag set, to a CXXStdInitializerListExpr containing a MaterializeTemporaryExpr
containing an InitListExpr (possibly wrapped in a CXXBindTemporaryExpr).
This more detailed representation has several advantages, the most important of
which is that the new MaterializeTemporaryExpr allows us to directly model
lifetime extension of the underlying temporary array. Using that, this patch
*drastically* simplifies the IR generation of this construct, provides IR
generation support for nested global initializer_list objects, fixes several
bugs where the destructors for the underlying array would accidentally not get
invoked, and provides constant expression evaluation support for
std::initializer_list objects.
llvm-svn: 183872
CXXCtorInitializers to the point where we perform the questionable lifetime
extension. This exposed a selection of false negatives in the warning.
llvm-svn: 183869
were lacking ExprWithCleanups nodes in some cases where the new approach to
lifetime extension needed them).
Original commit message:
Rework IR emission for lifetime-extended temporaries. Instead of trying to walk
into the expression and dig out a single lifetime-extended entity and manually
pull its cleanup outside the expression, instead keep a list of the cleanups
which we'll need to emit when we get to the end of the full-expression. Also
emit those cleanups early, as EH-only cleanups, to cover the case that the
full-expression does not terminate normally. This allows IR generation to
properly model temporary lifetime when multiple temporaries are extended by the
same declaration.
We have a pre-existing bug where an exception thrown from a temporary's
destructor does not clean up lifetime-extended temporaries created in the same
expression and extended to automatic storage duration; that is not fixed by
this patch.
llvm-svn: 183859
with a string. This case is sort of tricky because we can't modify the
StringLiteral used to represent such initializers.
We are forced to decompose the string into individual characters.
Fixes <rdar://problem/10465114>.
llvm-svn: 183791
into the expression and dig out a single lifetime-extended entity and manually
pull its cleanup outside the expression, instead keep a list of the cleanups
which we'll need to emit when we get to the end of the full-expression. Also
emit those cleanups early, as EH-only cleanups, to cover the case that the
full-expression does not terminate normally. This allows IR generation to
properly model temporary lifetime when multiple temporaries are extended by the
same declaration.
We have a pre-existing bug where an exception thrown from a temporary's
destructor does not clean up lifetime-extended temporaries created in the same
expression and extended to automatic storage duration; that is not fixed by
this patch.
llvm-svn: 183721
handle temporaries which have been lifetime-extended to static storage duration
within constant expressions. This correctly handles nested lifetime extension
(through reference members of aggregates in aggregate initializers) but
non-constant-expression emission hasn't yet been updated to do the same.
llvm-svn: 183283
This commit improves Clang's diagnostics for string initialization.
Where it would previously say:
/tmp/a.c:3:9: error: array initializer must be an initializer list
wchar_t s[] = "Hi";
^
/tmp/a.c:4:6: error: array initializer must be an initializer list or string literal
char t[] = L"Hi";
^
It will now say
/tmp/a.c:3:9: error: initializing wide char array with non-wide string literal
wchar_t s[] = "Hi";
^
/tmp/a.c:4:6: error: initializing char array with wide string literal
char t[] = L"Hi";
^
As a bonus, it also fixes the fact that Clang would previously reject
this valid C11 code:
char16_t s[] = u"hi";
char32_t t[] = U"hi";
because it would only recognize the built-in types for char16_t and
char32_t, which do not exist in C.
llvm-svn: 181880
MSVC provides __wchar_t. This is the same as the built-in wchar_t type
from C++, but it is also available with -fno-wchar and in C.
The commit changes ASTContext to have two different types for this:
- WCharTy is the built-in type used for wchar_t in C++ and __wchar_t.
- WideCharTy is the type of a wide character literal. In C++ this is
the same as WCharTy, and in C it is an integer type compatible with
the type in <stddef.h>.
This fixes PR15815.
llvm-svn: 181587
- References to ObjC bit-field ivars are bit-field lvalues;
fixes rdar://13794269, which got me started down this.
- Introduce Expr::refersToBitField, switch a couple users to
it where semantically important, and comment the difference
between this and the existing API.
- Discourage Expr::getBitField by making it a bit longer and
less general-sounding.
- Lock down on const_casts of bit-field gl-values until we
hear back from the committee as to whether they're allowed.
llvm-svn: 181252
Previously, this compound literal expression (a GNU extension in C++):
(AggregateWithDtor){1, 2}
resulted in this AST:
`-CXXBindTemporaryExpr [...] 'struct Point' (CXXTemporary [...])
`-CompoundLiteralExpr [...] 'struct AggregateWithDtor'
`-CXXBindTemporaryExpr [...] 'struct AggregateWithDtor' (CXXTemporary [...])
`-InitListExpr [...] 'struct AggregateWithDtor'
|-IntegerLiteral [...] 'int' 1
`-IntegerLiteral [...] 'int' 2
Note the two CXXBindTemporaryExprs. The InitListExpr is really part of the
CompoundLiteralExpr, not an object in its own right. By introducing a new
entity initialization kind in Sema specifically for compound literals, we
avoid the treatment of the inner InitListExpr as a temporary.
`-CXXBindTemporaryExpr [...] 'struct Point' (CXXTemporary [...])
`-CompoundLiteralExpr [...] 'struct AggregateWithDtor'
`-InitListExpr [...] 'struct AggregateWithDtor'
|-IntegerLiteral [...] 'int' 1
`-IntegerLiteral [...] 'int' 2
llvm-svn: 181212
to use. This makes very little difference right now (other than suppressing
follow-on errors in some cases), but will matter more once we support deduced
return types (we don't want expressions with undeduced return types in the
AST).
llvm-svn: 181107
Add a CXXDefaultInitExpr, analogous to CXXDefaultArgExpr, and use it both in
CXXCtorInitializers and in InitListExprs to represent a default initializer.
There's an additional complication here: because the default initializer can
refer to the initialized object via its 'this' pointer, we need to make sure
that 'this' points to the right thing within the evaluation.
llvm-svn: 179958
For this source:
const int &ref = someStruct.bitfield;
We used to generate this AST:
DeclStmt [...]
`-VarDecl [...] ref 'const int &'
`-MaterializeTemporaryExpr [...] 'const int' lvalue
`-ImplicitCastExpr [...] 'const int' lvalue <NoOp>
`-MemberExpr [...] 'int' lvalue bitfield .bitfield [...]
`-DeclRefExpr [...] 'struct X' lvalue ParmVar [...] 'someStruct' 'struct X'
Notice the lvalue inside the MaterializeTemporaryExpr, which is very
confusing (and caused an assertion to fire in the analyzer - PR15694).
We now generate this:
DeclStmt [...]
`-VarDecl [...] ref 'const int &'
`-MaterializeTemporaryExpr [...] 'const int' lvalue
`-ImplicitCastExpr [...] 'int' <LValueToRValue>
`-MemberExpr [...] 'int' lvalue bitfield .bitfield [...]
`-DeclRefExpr [...] 'struct X' lvalue ParmVar [...] 'someStruct' 'struct X'
Which makes a lot more sense. This allows us to remove code in both
CodeGen and AST that hacked around this special case.
The commit also makes Clang accept this (legal) C++11 code:
int &&ref = std::move(someStruct).bitfield
PR15694 / <rdar://problem/13600396>
llvm-svn: 179250
The TypeLoc hierarchy used the llvm::cast machinery to perform undefined
behavior by casting pointers/references to TypeLoc objects to derived types
and then using the derived copy constructors (or even returning pointers to
derived types that actually point to the original TypeLoc object).
Some context is in this thread:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-December/056804.html
Though it's spread over a few months which can be hard to read in the mail
archive.
llvm-svn: 175462
MarkMemberReferenced instead of marking functions referenced directly. An audit
of callers to MarkFunctionReferenced and DiagnoseUseOfDecl also caused a few
other changes:
* don't mark functions odr-used when considering them for an initialization
sequence. Do mark them referenced though.
* the function nominated by the cleanup attribute should be diagnosed.
* operator new/delete should be diagnosed when building a 'new' expression.
llvm-svn: 174951
resolving an overloaded function reference within an initializer list.
Previously we would try to resolve the overloaded function reference without
first stripping off the InitListExpr wrapper.
llvm-svn: 172517
