Commit Graph

18 Commits

Author SHA1 Message Date
Richard Smith 006bfc91e8 constexpr: remove integral conversion overflow checking introduced in r149286.
As Eli points out, this is implementation-defined, and the way we define it
makes this fine.

llvm-svn: 149327
2012-01-31 01:47:46 +00:00
Richard Smith 911e142f03 constexpr: disallow signed integer overflow in integral conversions in constant
expressions in C++11.

llvm-svn: 149286
2012-01-30 22:27:01 +00:00
Richard Smith f8379a0fc3 constexpr: converted constant expression handling for enumerator values, case
values and non-type template arguments of integral and enumeration types.

This change causes some legal C++98 code to no longer compile in C++11 mode, by
enforcing the C++11 rule that narrowing integral conversions are not permitted
in the final implicit conversion sequence for the above cases.

llvm-svn: 148439
2012-01-18 23:55:52 +00:00
Richard Smith 2ec4061e39 Pedantic diagnostic correction: in C++, we have integral constant expressions,
not integer constant expressions. In passing, fix the 'folding is an extension'
diagnostic to not claim we're accepting the code, since that's not true in
-pedantic-errors mode, and add this diagnostic to -Wgnu.

llvm-svn: 148209
2012-01-15 03:51:30 +00:00
Richard Smith 02ab9c2940 Allow constant-folding of references which were formed in a manner not permitted
in a constant expression, for compatibility with g++.

llvm-svn: 148020
2012-01-12 06:08:57 +00:00
Richard Smith a8105bc9ce C++11 generalized constant expressions: implement checking and diagnostics for
pointer-arithmetic-related undefined behavior and unspecified results. We
continue to fold such values, but now notice they aren't constant expressions.

llvm-svn: 147659
2012-01-06 16:39:00 +00:00
Richard Smith fddd384b73 Unrevert r147271, reverted in r147361.
Also temporarily remove the assumption from IR gen that we can emit IR for every
constant we can fold, since it isn't currently true in C++11, to fix PR11676.

Original comment from r147271:

constexpr: perform zero-initialization prior to / instead of performing a
constructor call when appropriate. Thanks to Eli for spotting this.

llvm-svn: 147384
2011-12-30 21:15:51 +00:00
Rafael Espindola fafe4b7572 Revert r147271. This fixes PR11676.
llvm-svn: 147362
2011-12-30 03:11:50 +00:00
Richard Smith 6e52514c5d constexpr: support for evaluation and codegen of typeid constants.
llvm-svn: 147290
2011-12-27 12:18:28 +00:00
Richard Smith 771c4a1775 constexpr: perform zero-initialization prior to / instead of performing a
constructor call when appropriate. Thanks to Eli for spotting this.

llvm-svn: 147271
2011-12-25 20:00:17 +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 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 Smith 864711ee9f Reduce recursion limit on this test further to try to make the msys bot green.
llvm-svn: 146759
2011-12-16 21:59:02 +00:00
Richard Smith f6f003af6a C++11 constexpr: Add note stacks containing backtraces if constant evaluation
fails within a call to a constexpr function. Add -fconstexpr-backtrace-limit
argument to driver and frontend, to control the maximum number of notes so
produced (default 10). Fix APValue printing to be able to pretty-print all
APValue types, and move the testing for this functionality from a unittest to
a -verify test now that it's visible in clang's output.

llvm-svn: 146749
2011-12-16 19:06:07 +00:00
Richard Smith 9af58d4426 Halve the constexpr recursion depth in this test in an attempt to make the
freebsd bots happy. In the longer term, we should have a mechanism for moving
constexpr recursion off the call stack, to support the default limit of 512
suggested by the standard.

llvm-svn: 146596
2011-12-14 21:55:23 +00:00
Richard Smith 357362d00b Add checks and diagnostics for many of the cases which C++11 considers to not
be constant expressions.

llvm-svn: 146479
2011-12-13 06:39:58 +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
Douglas Gregor fcafc6e3de Implement the initial part of C++0x [expr.const]p2, which specifies
that the unevaluated subexpressions of &&, ||, and ? : are not
considered when determining whether the expression is a constant
expression. Also, turn the "used in its own initializer" warning into
a runtime-behavior warning, so that it doesn't fire when a variable is
used as part of an unevaluated subexpression of its own initializer.

Fixes PR9999.

llvm-svn: 131968
2011-05-24 16:02:01 +00:00