This second patch introduces mfpr_float_ops, an new implementation
of target_float_ops. This implements precise emulation of target
floating-point formats using the MPFR library. This is then used
to perform operations on types that do not match any host type.
Note that use of MPFR is still not required. The patch adds
a configure option --with-mpfr similar to --with-expat. If use of
MPFR is disabled via the option or MPFR is not available, code will
fall back to current behavior. This means that operations on types
that do not match any host type will be implemented on the host
long double type instead.
A new test case verifies that we can correctly print the largest
__float128 value now.
gdb/ChangeLog:
2017-11-22 Ulrich Weigand <uweigand@de.ibm.com>
* NEWS: Document use of GNU MPFR.
* README: Likewise.
* Makefile.in (LIBMPFR): Add define.
(CLIBS): Add $(LIBMPFR).
* configure.ac: Add --with-mpfr configure option.
* configure: Regenerate.
* config.in: Regenerate.
* target-float.c [HAVE_LIBMPFR]: Include <mpfr.h>.
(class mpfr_float_ops): New type.
(mpfr_float_ops::from_target): Two new overloaded functions.
(mpfr_float_ops::to_target): Likewise.
(mpfr_float_ops::to_string): New function.
(mpfr_float_ops::from_string): Likewise.
(mpfr_float_ops::to_longest): Likewise.
(mpfr_float_ops::from_longest): Likewise.
(mpfr_float_ops::from_ulongest): Likewise.
(mpfr_float_ops::to_host_double): Likewise.
(mpfr_float_ops::from_host_double): Likewise.
(mpfr_float_ops::convert): Likewise.
(mpfr_float_ops::binop): Likewise.
(mpfr_float_ops::compare): Likewise.
(get_target_float_ops): Use mpfr_float_ops if available.
gdb/doc/ChangeLog:
2017-11-22 Ulrich Weigand <uweigand@de.ibm.com>
* gdb.texinfo (Requirements): Document use of GNU MPFR.
gdb/testsuite/ChangeLog:
2017-11-22 Ulrich Weigand <uweigand@de.ibm.com>
* gdb.base/float128.c (large128): New variable.
* gdb.base/float128.exp: Add test to print largest __float128 value.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
Now that all the prerequisites are in place, this commit finally adds support
for handling the __float128 type on Intel and Power, by providing appropriate
platform-specific versions of the floatformat_for_type callback.
Since at this point we do not yet have any indication in the debug info to
distinguish different floating-point formats of the same length, we simply
use the type name as hint. Types named "__float128" get the IEEE format.
In addition to handling "__float128" itself, we also recognize "_Float128"
and (on Power) "_Float64x", as well as the complex versions of those.
(As pointed out by Joseph Myers, starting with GCC 7, __float128 is just
a typedef for _Float128 -- but it's good to handle this anyway.)
A new test case does some simple verification that the format is decoded
correctly, using both __float128 and "long double" to make sure using both
in the same file still works. Another new test verifies handling of the
_FloatN and _FloatNx types supported by GCC 7, as well as the complex
versions of those types.
Note that this still only supports basic format decoding and encoding.
We do not yet support the GNU extension 'g' suffix for __float128 constants.
In addition, since all *arithmetic* on floating-point values is still
performed in native host "long double" arithmetic, if that format is not
able to encode all target __float128 values, we may get incorrect results.
(To fix this would require implementing fully synthetic target floating-
point arithmetic along the lines of GCC's real.c, presumably using MPFR.)
gdb/ChangeLog:
* i386-tdep.c (i386_floatformat_for_type): New function.
(i386_gdbarch_init): Install it.
* ppc-linux-tdep.c (ppc_floatformat_for_type): New function.
(ppc_linux_init_abi): Install it.
gdb/testsuite/ChangeLog:
* gdb.base/float128.c: New file.
* gdb.base/float128.exp: Likewise.
* gdb.base/floatn.c: Likewise.
* gdb.base/floatn.exp: Likewise.
Signed-off-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Ulrich Weigand
Joel Brobecker
Luis Machado