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Simon Marchi f8c4185131 gdb: really share partial symtabs when using .gdb_index or .debug_names
Fix/follow-up to commit 17ee85fc2a ("Share DWARF partial symtabs").

In the non-index case, where GDB builds partial symbols from scratch,
two objfiles around the same BFD correctly share partial symtabs.  The
first objfile, which has to do all the work, saves a reference to the
created partial symtabs in the shared per_bfd object (at the end of
dwarf2_build_psymtabs).  The second objfile, when it reaches
dwarf2_build_psymtabs, sees that there are already partial symtabs built
for this BFD and just uses it.

However, that commit missed implementing the same sharing for cases
where GDB uses .gdb_index or .debug_names to build the partial symtabs.

This patch fixes it by having the first objfile to use the BFD set
per_bfd->partial_symtabs at the end of dwarf2_read_gdb_index /
dwarf2_read_debug_names.  For the subsequent objfiles using that BFD,
the partial symtabs are then picked up in dwarf2_initialize_objfile.

This patch adds a test that mimics how the issue was originally
triggered:

  1. Load the test file twice, such that the second objfile re-uses the
     per_bfd object created for the first objfile.
  2. Run to some point where in the backtrace there is a frame for a
     function that's in a CU that's not yet read in.
  3. Check that this frame's information is complete in the "backtrace"
     output.

Step 2 requires an address -> symbol lookup which uses the addrmap at
objfile->partial_symtabs->psymtabs_addrmap.  If the
objfile->partial_symtabs link is not properly setup (as is the case
before this patch), the symbol for that frame won't be found and we'll
get a frame with incomplete information.

The test fails without the fix when using boards "cc-with-gdb-index" and
"cc-with-debug-names".

gdb/ChangeLog:

	* dwarf2/read.c (dwarf2_read_gdb_index): Save partial_symtabs in
	the per_bfd object.
	(dwarf2_read_debug_names): Likewise.
	(dwarf2_initialize_objfile): Use partial_symtabs from per_bfd
	object when re-using a per_bfd object with an index.

gdb/testsuite/ChangeLog:

	* gdb.dwarf2/share-psymtabs-bt.exp: New file.
	* gdb.dwarf2/share-psymtabs-bt.c: New file.
	* gdb.dwarf2/share-psymtabs-bt-2.c: New file.

Change-Id: Ibb26210e2dfc03b80ba9fa56b875ba4cc58c0352
2020-06-04 13:58:48 -04:00
bfd x86: Remove target_id from elf_x86_link_hash_table 2020-06-04 09:56:25 -07:00
binutils opcodes: support insn endianness in cgen_cpu_open 2020-06-04 16:17:42 +02:00
config
contrib
cpu cpu,gas,opcodes: remove no longer needed workaround from the BPF port 2020-06-04 16:17:42 +02:00
elfcpp
etc
gas gas: simplify code in tc-bpf.c:md_apply_fix 2020-06-04 16:34:16 +02:00
gdb gdb: really share partial symtabs when using .gdb_index or .debug_names 2020-06-04 13:58:48 -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
gold
gprof
include opcodes: discriminate endianness and insn-endianness in CGEN ports 2020-06-04 16:17:42 +02:00
intl
ld ELF: Don't check relocations in non-loaded, non-alloced sections 2020-06-04 05:58:47 -07:00
libctf
libdecnumber
libiberty
opcodes cpu,gas,opcodes: remove no longer needed workaround from the BPF port 2020-06-04 16:17:42 +02:00
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