Issue 090109.1: Support C++0x new string literals
Background
----------
For detail description of the feature, please refer to:
http://en.wikipedia.org/wiki/C%2B%2B0x#New_string_literals
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2442.htm
Overview
--------
C++0x will support three Unicode encodings: UTF-8, UTF-16 and UTF-32.
*char* has a size big enough to hold a UTF-8 character and can be used
to hold UTF-8 characters.
Two new types are also introduced:
* *char16_t* has a size big enough to hold a UTF-16 character and
can be used to hold UTF-16 characters.
* *char32_t* has a size big enough to hold a UTF-32 character and
can be used to hold UTF-32 characters.
Purpose
* New base type debug information entries are required to represent
char16_t and char32_t.
* The combination of existing DW_AT_encoding and DW_AT_byte_size can
be used to describe character type of various sizes.
* New debug information is needed to describe the encoding used for
the character type. This can be achieved either by creating new
values for DW_AT_encoding or by creating new attributes.
* This proposal describes new attributes to describe the UTF8/16/32
encoding.
Proposed Changes to the DWARF Specification
-------------------------------------------
Purpose
* New base type debug information entries are required to represent
char16_t and char32_t.
* New debug information is needed to describe the encoding used for
the character type.
* This proposal describes new base type encodings for the UTF8/16/32 encoding.
7.8 Base Type Encodings
DW_ATE_utf 0x10
5.1: Base Type Entries
*For example, the C++ type char16_t is represented by a base type entry
with a name attribute whose value is "char16_t", an encoding attribute
whose value is DW_ATE_utf and a byte size attribute whose value is 2.*
Appendix
D.9 UTF character type examples
char16_t chr_a = u'h';
char32_t chr_b = U'h';
1$: DW_TAG_base_type
DW_AT_name("char16_t")
DW_AT_encoding(DW_ATE_utf)
DW_AT_byte_size(2)
2$: DW_TAG_base_type
DW_AT_name("char32_t")
DW_AT_encoding(DW_ATE_utf)
DW_AT_byte_size(4)
3$: DW_TAG_variable
DW_AT_name("chr_a")
DW_AT_type(reference to 1$)
4$: DW_TAG_variable
DW_AT_name("chr_b")
DW_AT_type(reference to 2$)
--
Revised history:
March 17, 2009 -- Add DW_ATE_utf to describe UTF encoding
April 20, 2009 -- Re-format DWARF description in Example section to
match current documentation.
