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Andrew Burgess 9f0272f854 gdb/riscv: Handle empty C++ structs during argument passing
This commit resolves a large number of failures in the test script
gdb.base/infcall-nested-structs.exp which were caused by GDB (for
RISC-V) incorrectly handling empty C++ structures when preparing
arguments for a dummy call, or collecting a return value.

The issue is further complicated in that there was a bug in GCC, such
that in some cases GCC would generate incorrect code when passing a
small structure that contained empty sub-structures.  This was fixed
in GCC trunk on 5-March-2019, so in order to see the best results with
this patch you'll need a recent version of GCC.

Anything that used to work should continue to work after this patch,
regardless of GCC version being used.

The fix in this commit is that GDB now pays more attention to the
offset of fields within a structure when preparing arguments as in C++
an empty structure has a non-zero size, this is an example:

  struct s1 { struct s2 { } empty; int f; };

We previously assumed that 'f' was at offset 0 inside type 's1',
however this is not the case in C++ as 's2' has size 1, and with
alignment 'f' is likely at some even bigger offset inside 's1'.

gdb/ChangeLog:

	* riscv-tdep.c (riscv_call_arg_complex_float): Fix offset of first
	component to 0.
	(riscv_struct_info::riscv_struct_info): Initialise m_offsets
	member.
	(riscv_struct_info::analyse): New implementation using new
	analyse_inner member function.
	(riscv_struct_info::field_offset): New member function.
	(riscv_struct_info::m_offsets): New member variable.
	(riscv_struct_info::analyse_inner): New private member function,
	takes the old implementation of riscv_struct_info::analyse but
	extended to track field offsets.
	(riscv_call_arg_struct): Update the struct folding special cases
	to handle cases where empty C++ structs, which are non-zero
	length, are found.
	(riscv_arg_location): Initialise the length of each location, a
	non-zero length now indicates the location is in use.
	(riscv_push_dummy_call): Allow for the first location having a
	non-zero offset when setting up arguments.
	(riscv_return_value): Likewise, but for return values.
2019-04-11 23:37:45 +01:00
bfd x86: Add -z cet-report=[none|warning|error] 2019-04-11 08:21:30 -07:00
binutils x86: Define GNU_PROPERTY_X86_ISA_1_AVX512_BF16 2019-04-08 17:04:16 -07:00
config
contrib
cpu
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gas xtensa: gas: add relaxations tests 2019-04-11 11:42:12 -07:00
gdb gdb/riscv: Handle empty C++ structs during argument passing 2019-04-11 23:37:45 +01:00
gold
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include [BINUTILS, AArch64, 2/2] Update Store Allocation Tag instructions 2019-04-11 10:19:37 +01:00
intl
ld ld: Add --no-print-map-discarded option 2019-04-11 10:16:31 -07:00
libdecnumber
libiberty Pull in patch for libiberty that fixes a stack exhaustion bug when demangling a pathalogically constructed mangled name. 2019-04-10 15:49:36 +01:00
opcodes [BINUTILS, AArch64, 2/2] Update Store Allocation Tag instructions 2019-04-11 10:19:37 +01:00
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ChangeLog Pull in patch for libiberty that fixes a stack exhaustion bug when demangling a pathalogically constructed mangled name. 2019-04-10 15:49:36 +01:00
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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,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
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	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	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
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
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If you have more than one compiler on your system, it is often best to
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also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

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the Free Software Foundation, Inc.  See the file COPYING or
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GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.