Commit Graph

25 Commits

Author SHA1 Message Date
Richard Smith 3607ffee5c Update constexpr implementation to match CWG's chosen approach for core issues
1358, 1360, 1452 and 1453.
 - Instantiations of constexpr functions are always constexpr. This removes the
   need for separate declaration/definition checking, which is now gone.
 - This makes it possible for a constexpr function to be virtual, if they are
   only dependently virtual. Virtual calls to such functions are not constant
   expressions.
 - Likewise, it's now possible for a literal type to have virtual base classes.
   A constexpr constructor for such a type cannot actually produce a constant
   expression, though, so add a special-case diagnostic for a constructor call
   to such a type rather than trying to evaluate it.
 - Classes with trivial default constructors (for which value initialization can
   produce a fully-initialized value) are considered literal types.
 - Classes with volatile members are not literal types.
 - constexpr constructors can be members of non-literal types. We do not yet use
   static initialization for global objects constructed in this way.

llvm-svn: 150359
2012-02-13 03:54:03 +00:00
Richard Smith 4d59eebb49 DR1359: A constexpr constructor does not need to initialize an empty struct or
empty union. This still rejects anonymous member structs or unions which only
contain such empty class types, pending standard wording defining exactly what
an empty class type is.

llvm-svn: 150157
2012-02-09 06:40:58 +00:00
Richard Smith 2de5a939e2 constexpr: Implement DR1358: An instantiation of a constexpr function which
can't produce a constant expression is not ill-formed (so long as some
instantiation of that function can produce a constant expression).

llvm-svn: 149802
2012-02-05 02:30:54 +00:00
Richard Smith 84f6dcf2b5 constexpr:
* support the gcc __builtin_constant_p() ? ... : ... folding hack in C++11
  * check for unspecified values in pointer comparisons and pointer subtractions

llvm-svn: 149578
2012-02-02 01:16:57 +00:00
Richard Smith 0287910521 constexpr: Unlike other incomplete types, 'void' cannot possibly be completed as
a literal type. Disallow it as the return type of a constexpr function
declaration.

llvm-svn: 149469
2012-02-01 04:40:02 +00:00
Richard Smith 253c2a390a constexpr: Implement the [dcl.constexpr]p5 check for whether a constexpr
function definition can produce a constant expression. This also provides the
last few checks for [dcl.constexpr]p3 and [dcl.constexpr]p4.

llvm-svn: 149108
2012-01-27 01:14:48 +00:00
Richard Smith 7971b69f74 PR11754: Reject non-static constexpr member functions in classes with virtual
base classes.

llvm-svn: 148094
2012-01-13 04:54:00 +00:00
Eli Friedman c8002429e5 constexpr is allowed on static member functions of non-literal classes. Per report on cfe-dev.
llvm-svn: 148090
2012-01-13 02:31:53 +00:00
Richard Smith cc36f698af PR11614: Mark defaulted special constructors as constexpr if their implicit
definition would satisfy the constexpr requirements.

llvm-svn: 147128
2011-12-22 02:22:31 +00:00
Richard Smith f2b681b4d8 constexpr: diagnostic improvements for invalid lvalue-to-rvalue conversions in
constant expressions.

llvm-svn: 147035
2011-12-21 05:04:46 +00:00
Richard Smith 242ad89a15 C++11 half of r147023: In C++11, additionally eagerly instantiate:
- constexpr function template instantiations
 - variables of reference type
 - constexpr variables

llvm-svn: 147031
2011-12-21 02:55:12 +00:00
Richard Smith d0b4dd656d constexpr handling improvements. Produce detailed diagnostics when a 'constexpr'
variable is initialized by a non-constant expression, and pass in the variable
being declared so that earlier-initialized fields' values can be used.

Rearrange VarDecl init evaluation to make this possible, and in so doing fix a
long-standing issue in our C++ constant expression handling, where we would
mishandle cases like:

  extern const int a;
  const int n = a;
  const int a = 5;
  int arr[n];

Here, n is not initialized by a constant expression, so can't be used in an ICE,
even though the initialization expression would be an ICE if it appeared later
in the TU. This requires computing whether the initializer is an ICE eagerly,
and saving that information in PCH files.

llvm-svn: 146856
2011-12-19 06:19:21 +00:00
Richard Trieu 553b2b2e5d Modify how the -verify flag works. Currently, the verification string and
diagnostic message are compared.  If either is a substring of the other, then
no error is given.  This gives rise to an unexpected case:

  // expect-error{{candidate function has different number of parameters}}

will match the following error messages from Clang:

  candidate function has different number of parameters (expected 1 but has 2)
  candidate function has different number of parameters

It will also match these other error messages:

  candidate function
  function has different number of parameters
  number of parameters

This patch will change so that the verification string must be a substring of
the diagnostic message before accepting.  Also, all the failing tests from this
change have been corrected.  Some stats from this cleanup:

87 - removed extra spaces around verification strings
70 - wording updates to diagnostics
40 - extra leading or trailing characters (typos, unmatched parens or quotes)
35 - diagnostic level was included (error:, warning:, or note:)
18 - flag name put in the warning (-Wprotocol)

llvm-svn: 146619
2011-12-15 00:38:15 +00:00
Richard Smith ce40ad677e Represent an APValue based on a Decl as that Decl, rather than a DeclRefExpr
or MemberExpr which refers to it. As a side-effect, MemberExprs which refer to
static member functions and static data members are now emitted as constant
expressions.

llvm-svn: 144468
2011-11-12 22:28:03 +00:00
Richard Smith d62306a481 Constant expression evaluation: support for evaluation of structs and unions of
literal types, as well as derived-to-base casts for lvalues and
derived-to-virtual-base casts.

llvm-svn: 144265
2011-11-10 06:34:14 +00:00
Richard Smith eda3c84698 constexpr: static data members declared constexpr are required to have an
initializer; all other constexpr variables are merely required to be
initialized. In particular, a user-provided constexpr default constructor can be
used for such initialization.

llvm-svn: 144028
2011-11-07 22:16:17 +00:00
Richard Smith 53cafabac0 Add test missed from r143234.
llvm-svn: 143257
2011-10-29 00:03:08 +00:00
Peter Collingbourne e109a2ca59 Attach class template attributes to the templated CXXRecordDecl,
instead of silently discarding them.

As a side effect, this improves diagnostics for constexpr class
templates slightly.

llvm-svn: 142755
2011-10-23 17:07:16 +00:00
Richard Smith 9ca5c42582 Update all tests other than Driver/std.cpp to use -std=c++11 rather than
-std=c++0x. Patch by Ahmed Charles!

llvm-svn: 141900
2011-10-13 22:29:44 +00:00
Richard Smith f368fb40df constexpr: Disable checking of constructor member initializer lists for
constexpr constructor templates. Such checking is optional, and currently hard
to get right since clang doesn't generate implicit member initializers until
instantiation (even for non-dependent members).

This is needed for clang to accept libstdc++ from g++4.6 in c++0x mode.

llvm-svn: 141547
2011-10-10 16:38:04 +00:00
Richard Smith eb3c10c248 constexpr: semantic checking for constexpr functions and constructors. Based in
part on patches by Peter Collingbourne.

We diverge from the C++11 standard in a few areas, mostly related to checking
constexpr function declarations, and not just definitions. See WG21 paper
N3308=11-0078 for details.

Function invocation substitution is not available in this patch; constexpr
functions cannot yet be used from within constant expressions.

llvm-svn: 140926
2011-10-01 02:31:28 +00:00
Richard Smith 7cd25b2836 constexpr functions are implicitly const. More tests to follow.
llvm-svn: 140831
2011-09-30 00:45:47 +00:00
Richard Smith 2316cd8b79 constexpr: semantic checking for constexpr variables.
We had an extension which allowed const static class members of floating-point type to have in-class initializers, 'as a C++0x extension'. However, C++0x does not allow this. The extension has been kept, and extended to all literal types in C++0x mode (with a fixit to add the 'constexpr' specifier).

llvm-svn: 140801
2011-09-29 19:11:37 +00:00
Richard Smith a77a0a6bf2 Track in the AST whether a function is constexpr.
llvm-svn: 137653
2011-08-15 21:04:07 +00:00
Sebastian Redl c3eba8f547 Commit my WIP on constexpr support. This commit: an XFAILed test and treating constexpr as a top-level const.
llvm-svn: 105752
2010-06-09 21:19:43 +00:00