[PATCH][gdb] Fix missing symtab includes
Tom de Vries
tdevries@suse.de
Fri Mar 27 20:49:50 GMT 2020
Hi,
Consider hello.h:
...
inline static const char*
foo (void)
{
return "foo";
}
...
and hello.c:
...
#include <stdio.h>
#include "hello.h"
int
main (void)
{
printf ("hello: %s\n", foo ());
return 0;
}
...
compiled with -g, and dwz-compressed:
...
$ gcc -g hello.c
$ dwz a.out
...
When breaking on foo and printing the symbol tables, we have two includes for
the hello.c compunit_symtab, representing two imported partial units:
...
$ gdb -iex "set language c" -batch a.out -ex "b foo" -ex "maint info symtabs"
Breakpoint 1 at 0x40050b: file hello.h, line 4.
...
{ ((struct compunit_symtab *) 0x38fa890)
debugformat DWARF 2
producer GNU C11 7.5.0 -mtune=generic -march=x86-64 -g
dirname /data/gdb_versions/devel
blockvector ((struct blockvector *) 0x39af9f0)
user ((struct compunit_symtab *) (null))
( includes
((struct compunit_symtab *) 0x39afb10)
((struct compunit_symtab *) 0x39b00c0)
)
{ symtab hello.c ((struct symtab *) 0x38fa940)
fullname (null)
linetable ((struct linetable *) 0x39afa80)
}
...
But if we instead break on the same location using a linespec, the includes
are gone:
...
$ gdb -iex "set language c" -batch a.out -ex "b hello.h:4" -ex "maint info symtabs"
Breakpoint 1 at 0x40050b: file hello.h, line 4.
...
{ ((struct compunit_symtab *) 0x2283500)
debugformat DWARF 2
producer GNU C11 7.5.0 -mtune=generic -march=x86-64 -g
dirname /data/gdb_versions/devel
blockvector ((struct blockvector *) 0x23086c0)
user ((struct compunit_symtab *) (null))
{ symtab hello.c ((struct symtab *) 0x22835b0)
fullname (null)
linetable ((struct linetable *) 0x2308750)
}
...
The includes are calculated by process_cu_includes in gdb/dwarf2/read.c.
In the case of "b foo":
- the hello.c partial symtab is found to contain foo
- the hello.c partial symtab is expanded using psymtab_to_symtab
- psymtab_to_symtab calls dwarf2_psymtab::read_symtab
- dwarf2_psymtab::read_symtab calls dwarf2_psymtab::expand_psymtab
- dwarf2_psymtab::read_symtab calls process_cu_includes, and we have the
includes
In the case of "b hello.h:4":
- the hello.h partial symtab is found to represent hello.h
- the hello.h partial symtab is expanded using psymtab_to_symtab
- psymtab_to_symtab calls dwarf2_include_psymtab::read_symtab
- dwarf2_include_psymtab::read_symtab calls
dwarf2_include_psymtab::expand_psymtab
- dwarf2_include_psymtab::expand_psymtab calls
partial_symtab::read_dependencies
- partial_symtab::read_dependencies calls dwarf2_psymtab::expand_psymtab
for partial symtab hello.c
- the hello.c partial symtab is expanded using dwarf2_psymtab::expand_psymtab
- process_cu_includes is never called
Fix this by making sure in dwarf2_include_psymtab::expand_psymtab that
read_symtab rather than expand_symtab is called for the hello.c partial
symtab.
Tested on x86_64-linux, with native, and target board cc-with-dwz and
cc-with-dwz-m.
OK for trunk?
Thanks,
- Tom
[gdb] Fix missing symtab includes
gdb/ChangeLog:
2020-03-27 Tom de Vries <tdevries@suse.de>
PR symtab/25718
* dwarf2/read.c (dwarf2_include_psymtab::expand_psymtab): Call
read_symtab instead of expand_symtab for dependency.
---
gdb/dwarf2/read.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 2465ecebe3..fb90a04061 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -5840,7 +5840,14 @@ struct dwarf2_include_psymtab : public partial_symtab
return;
/* It's an include file, no symbols to read for it.
Everything is in the parent symtab. */
- read_dependencies (objfile);
+
+ /* Make sure that we call read_symtab rather than just expand_symtab,
+ otherwise process_cu_includes is never called, and the expanded symtab
+ will not have the correct value for the includes field (note:
+ confusingly, the mentioned includes field is related to imported units,
+ and has no relation to include as used in 'dwarf2_include_psymtab'). */
+ if (!dependencies[0]->readin_p ())
+ dependencies[0]->read_symtab (objfile);
m_readin = true;
}
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