clang should throw std::bad_array_new_length when the allocation size for new overflows

[efriedma-quic]

Bugzilla Link	11644
Version	unspecified
OS	All
CC	@AaronBallman,@DougGregor,@emaste,@miyuki

Extended Description

C++11 has a new exception type: std::bad_array_new_length. And per the standard, "If the value of that expression is less than zero or such that the size of the allocated object would exceed the implementation-defined limit, no storage is obtained and the new-expression terminates by throwing an exception of a type that would match a handler (15.3) of type std::bad_array_new_length". Our current behavior is likely good enough in most cases, but it isn't strictly compliant.

[llvmbot]

r208386 gives:

test.cpp:2:13: warning: expression result unused [-Wunused-value]
return (0 && ({lbl1:lbl2: 0;})), (long)&&lbl1 - (long)&&lbl2;
~ ^ ~~~~~~~~~~~~~~~~~
test.cpp:1:16: error: constexpr function never produces a constant expression [-Winvalid-constexpr]
constexpr long a() {
^
test.cpp:2:36: note: cast that performs the conversions of a reinterpret_cast is not allowed in a
constant expression
return (0 && ({lbl1:lbl2: 0;})), (long)&&lbl1 - (long)&&lbl2;
^

Is this bug report still valid?

[llvmbot]

Ignore the last comment please, pasted into wrong tab :(

[AaronBallman]

Fixed in r216675

[AaronBallman]

Reopening as this commit was reverted due to runtime support issues.

[TNorthover]

mentioned in issue llvm/llvm-bugzilla-archive#35573