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Simon Marchi 44486dcf19 gdb: use caller objfile in dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value
In commit

    89b07335fe ("Add dwarf2_per_objfile to dwarf_expr_context and dwarf2_frame_cache")

I replaced the offset property of dwarf_expr_context by a per_objfile
property (since we can get the text offset from the objfile).  The
previous code in dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value
(dwarf_evaluate_loc_desc derives from dwarf_expr_context) did
temporarily override the offset property while evaluating a DWARF
sub-expression.  I speculated that this sub-expression always came from
the same objfile as the outer expression, so I didn't see the need to
temporarily override the per_objfile property in the new code.  A later
commit:

    9f47c70716 ("Remove dwarf2_per_cu_data::objfile ()")

added the following assertion to verify this:

    gdb_assert (this->per_objfile == caller_per_objfile);

It turns out that this is not true.  Call sites can refer to function in
another objfile, and therefore the caller's objfile can be different
from the callee's objfile.  This can happen when the call site DIE in the
DWARF represents a function call done through a function pointer.  The
DIE can't describe statically which function is being called, since it's
variable and not known at compile time.  Instead, it provides an
expression that evaluates to the address of the function being called.
In this case, the called function can very well be in a separate
objfile.

Fix this by overriding the per_objfile property while evaluating the
sub-expression.

This was exposed by the gdb.base/catch-load.exp test failing on openSUSE
Tumbleweed with the glibc debug info installed.  It was also reported to
fail on Fedora.

When I investigated the problem, the particular call site on which we
did hit the assert was coming from this DIE, in
/usr/lib/debug/lib64/libc-2.31.so-2.31-5.1.x86_64.debug on openSUSE
Tumbleweed:

    0x0091aa10:     DW_TAG_GNU_call_site
                      DW_AT_low_pc [DW_FORM_addr]   (0x00000000001398e0)
                      DW_AT_GNU_call_site_target [DW_FORM_exprloc]  (DW_OP_fbreg -272, DW_OP_deref)
                      DW_AT_sibling [DW_FORM_ref4]  (0x0091aa2b)

And for you curious out there, this call site is found in this function:

    0x0091a91d:   DW_TAG_subprogram
                    DW_AT_external [DW_FORM_flag_present]   (true)
                    DW_AT_name [DW_FORM_strp]       ("_dl_catch_exception")
                    DW_AT_decl_file [DW_FORM_data1] ("/usr/src/debug/glibc-2.31-5.1.x86_64/elf/dl-error-skeleton.c")
                    ...

Which is a function that indeed uses a function pointer.

gdb/ChangeLog:

	* dwarf2/loc.c (class dwarf_evaluate_loc_desc)
	<push_dwarf_reg_entry_value>: Remove assert.  Override
	per_objfile with caller_per_objfile.

Change-Id: Ib227d767ce525c10607ab6621a373aaae982c67a
2020-05-28 11:31:00 -04:00
bfd Automatic date update in version.in 2020-05-28 00:00:16 +00:00
binutils ar many_files test 2020-05-23 14:56:07 +09:30
config Sync config with GCC 2020-05-16 06:07:12 -07:00
contrib contrib: Update dg-extract-results.* from gcc 2020-05-15 11:41:22 +01:00
cpu Replace "if (x) free (x)" with "free (x)", opcodes 2020-05-21 10:45:33 +09:30
elfcpp Add markers for 2.34 branch to the NEWS files and ChangeLogs. 2020-01-18 13:50:25 +00:00
etc texi2pod.pl: import support for @t{...} from gcc 2020-01-15 12:58:09 -05:00
gas [PATCH] gas: Fix comment on definition of frag_grow() 2020-05-28 14:30:34 +01:00
gdb gdb: use caller objfile in dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value 2020-05-28 11:31:00 -04:00
gdbserver Don't close process handle provided by WaitForDebugEvent 2020-05-27 19:20:01 +02:00
gdbsupport gdbsupport: Drop now unused function 'stringify_argv' 2020-05-25 11:40:35 -04:00
gnulib gdb: update gnulib import 2020-02-22 20:37:18 -05:00
gold PowerPC: downgrade FP mismatch error for shared libraries to a warning 2020-05-22 13:32:51 +09:30
gprof Replace "if (x) free (x)" with "free (x)", gprof 2020-05-21 10:45:33 +09:30
include PR26044, Some targets can't be compiled with GCC 10 (tilepro) 2020-05-28 21:11:51 +09:30
intl Regen with blessed automake-1.15.1 2020-02-20 13:02:24 +10:30
ld ld: Mention --enable-textrel-check=yes is default for Linux/x86 targets 2020-05-28 04:38:05 -07:00
libctf libctf: Mark bswap_identity_64 inline function as static. 2020-03-11 17:48:49 +10:30
libdecnumber
libiberty Sync config and libiberty with GCC 2020-05-12 18:37:03 -07:00
opcodes ubsan: nios2: undefined shift 2020-05-28 22:08:42 +09:30
readline Fix compilation of Readline on mingw.org's MinGW 2019-12-23 16:28:32 +02:00
sim sim: ppc: netbsd: Sync signal names with NetBSD 9.99.49 2020-03-12 16:07:37 +01:00
texinfo
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.cvsignore
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ar-lib
ChangeLog Since the pdp11-aout target does not support gdb, gdbserver or gprof these should be excluded in configure. 2020-04-21 10:27:50 +01:00
compile
config-ml.in
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config.rpath
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configure Since the pdp11-aout target does not support gdb, gdbserver or gprof these should be excluded in configure. 2020-04-21 10:27:50 +01:00
configure.ac Since the pdp11-aout target does not support gdb, gdbserver or gprof these should be excluded in configure. 2020-04-21 10:27:50 +01:00
COPYING
COPYING3
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COPYING.LIB
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depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
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MAINTAINERS Move gdbserver to top level 2020-02-07 08:42:25 -07:00
Makefile.def Change gdbserver to use existing gdbsupport 2020-03-12 13:32:16 -06:00
Makefile.in Change gdbserver to use existing gdbsupport 2020-03-12 13:32:16 -06:00
Makefile.tpl Revert "Sync top level files with versions from gcc." 2019-05-30 11:17:19 +01:00
makefile.vms
missing
mkdep
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setup.com
src-release.sh Move gdbserver to top level 2020-02-07 08:42:25 -07:00
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