Summary:
The existing detection of a format member function has a couple of deficiencies:
- the member function does not get detected if one calls formatv with an lvalue,
because the template parameter gets deduced as T&, which fails the is_class
check.
- it also did not work if the function was called with a const variable because
the template parameter would get deduced as const T&, again failing the
is_class check.
This fixes the problem by stripping the references in the uses_format_member
template, to make sure the type is correctly detected as class. It also provides
specializations of the has_FormatMember template for const and non-const members
of the types in order to enable declaring the format member as a "const"
function. I have added tests that verify that formatv can be now called in these
scenarios. As some scenarios could not be verified at runtime (e.g. making sure
that calling a non-const format member on a const object does *not* compile), I
have also added some static_asserts which test the behaviour of the template
classes used internally by formatv().
Reviewers: zturner
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27525
llvm-svn: 289040
This introduces a new type-safe general purpose formatting
library. It provides compile-time type safety, does not require
a format specifier (since the type is deduced), and provides
mechanisms for extending the format capability to user defined
types, and overriding the formatting behavior for existing types.
This patch additionally adds documentation for the API to the
LLVM programmer's manual.
Mailing List Thread:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/105836.html
Differential Revision: https://reviews.llvm.org/D25587
llvm-svn: 286682
