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Pedro Alves 53e710acd2 Fix PR c++/21323: GDB thinks char16_t and char32_t are signed in C++
While the C++ standard says that char16_t and char32_t are unsigned types:

 Types char16_t and char32_t denote distinct types with the same size,
 signedness, and alignment as uint_least16_t and uint_least32_t,
 respectively, in <cstdint>, called the underlying types.

... gdb treats them as signed currently:

 (gdb) p (char16_t)-1
 $1 = -1 u'\xffff'

There are actually two places in gdb that hardcode these types:

- gdbtypes.c:gdbtypes_post_init, when creating the built-in types,
  seemingly used by the "x /s" command (judging from commit 9a22f0d0).

- dwarf2read.c, when reading base types with DW_ATE_UTF encoding
  (which is what is used for these types, when compiling for C++11 and
  up).  Despite the comment, the type created does end up used.

Both places need fixing.  But since I couldn't tell why dwarf2read.c
needs to create a new type, I've made it use the per-arch built-in
types instead, so that the types are only created once per arch
instead of once per objfile.  That seems to work fine.

While writting the test, I noticed that the C++ language parser isn't
actually aware of these built-in types, so if you try to use them
without a program that uses them, you get:

 (gdb) set language c++
 (gdb) ptype char16_t
 No symbol table is loaded.  Use the "file" command.
 (gdb) ptype u"hello"
 No type named char16_t.
 (gdb) p u"hello"
 No type named char16_t.

That's fixed by simply adding a couple entries to C++'s built-in types
array in c-lang.c.  With that, we get the expected:

 (gdb) ptype char16_t
 type = char16_t
 (gdb) ptype u"hello"
 type = char16_t [6]
 (gdb) p u"hello"
 $1 = u"hello"

gdb/ChangeLog:
2017-04-12  Pedro Alves  <palves@redhat.com>

	PR c++/21323
	* c-lang.c (cplus_primitive_types) <cplus_primitive_type_char16_t,
	cplus_primitive_type_char32_t>: New enum values.
	(cplus_language_arch_info): Register cplus_primitive_type_char16_t
	and cplus_primitive_type_char32_t.
	* dwarf2read.c (read_base_type) <DW_ATE_UTF>: If bit size is 16 or
	32, use the archtecture's built-in type for char16_t and char32_t,
	respectively.  Otherwise, fallback to init_integer_type as before,
	but make the type unsigned, and issue a complaint.
	* gdbtypes.c (gdbtypes_post_init): Make char16_t and char32_t unsigned.

gdb/testsuite/ChangeLog:
2017-04-12  Pedro Alves  <palves@redhat.com>

	PR c++/21323
	* gdb.cp/wide_char_types.c: New file.
	* gdb.cp/wide_char_types.exp: New file.
2017-04-12 14:00:49 +01:00
bfd Automatic date update in version.in 2017-04-12 00:00:43 +00:00
binutils Prevent a bigus warning from readelf about a gdb-index table being too big. 2017-04-10 16:27:05 +01:00
config
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gas Bye bye PPC_OPCODE_HTM and -mhtm 2017-04-11 07:40:24 +09:30
gdb Fix PR c++/21323: GDB thinks char16_t and char32_t are signed in C++ 2017-04-12 14:00:49 +01:00
gold
gprof
include Reorder PPC_OPCODE_* and set PPC_OPCODE_TMR for e6500 2017-04-11 07:43:21 +09:30
intl
ld PR 21274, ld segfaults linking PE DLL 2017-04-11 19:49:13 +09:30
libdecnumber
libiberty
opcodes Reorder PPC_OPCODE_* and set PPC_OPCODE_TMR for e6500 2017-04-11 07:43:21 +09:30
readline
sim Add support for fcvtl and fcvtl2. 2017-04-08 12:08:20 -07:00
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
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It is now possible to automatically configure and build a variety of
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	./configure 
	make

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	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
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	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

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