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Re: [PATCH][gdb] Fix gdb.dwarf2/amd64-entry-value-param.exp with -fPIE/-pie
On 16-08-19 20:33, Pedro Alves wrote:
> On 8/12/19 2:10 PM, Tom de Vries wrote:
>>> Tom> + CORE_ADDR baseaddr
>>> Tom> + = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
>>>
>>> I guess this assumes the text section - but then can the call to
>>> find_pc_section give anything else? Maybe it's just something to
>>> comment and move on.
>>>
>> I suppose that find_pc_section also can return .init or .fini., but I
>> imagine these wil have the same sections offsets as .text.
>>
>
> Hmm. That'll usually be the case on GNU/Linux and other standard
> operating systems, where you have a single text segment containing all sections.
> But they might well not have the same offsets if you're debugging a relocatable
> object, for example. Some targets' shared libraries are relocatable objects
> instead of fully linked binaries. See "Library List Format" in the manual:
>
> ~~~
> For the common case of libraries that are fully linked binaries, the
> library should have a list of segments. If the target supports
> dynamic linking of a relocatable object file, its library XML element
> should instead include a list of allocated sections. The segment or
> section bases are start addresses, not relocation offsets; they do not
> depend on the library's link-time base addresses.
> ~~~
>
> Linux kernel modules would be something like that too, I think.
>
> If easy, it seems better to look up the section.
Done.
Updated patch OK for trunk?
Thanks,
- Tom
[gdb] Fix gdb.dwarf2/amd64-entry-value-param.exp with -fPIE/-pie
When running gdb.dwarf2/amd64-entry-value-param.exp with target board
unix/-fPIE/-pie, we get:
...
FAIL: gdb.arch/amd64-entry-value-param.exp: call 1: p y
...
The problem is that read_call_site_scope attempts to put relocated addresses
in cu->call_site_htab, for both the pc field:
...
baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
...
pc = attr_value_as_address (attr) + baseaddr;
pc = gdbarch_adjust_dwarf2_addr (gdbarch, pc);
...
call_site->pc = pc;
...
and the target field:
...
lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
SET_FIELD_PHYSADDR (call_site->target, lowpc);
...
but fails to do so because it is called before objfile_relocate, making
baseaddr 0.
Fix this by eliminating baseaddr from read_call_site_scope, and handling the
relocation offset at the use sites in call_site_for_pc and
call_site_to_target_addr.
Tested on x86_64-linux, both with and without -fPIE/-pie.
gdb/ChangeLog:
2019-08-09 Tom de Vries <tdevries@suse.de>
PR gdb/24892
* objfiles.c (find_objfile_section_for_unrelocated_addr)
(relocate_pc_addr): New function.
* objfiles.h (relocate_pc_addr): Declare.
* block.c (call_site_for_pc): Substract relocation offset before
finding pc in COMPUNIT_CALL_SITE_HTAB.
* dwarf2loc.c (call_site_to_target_addr): Add relocation offset to
FIELD_STATIC_PHYSADDR (call_site->target).
* dwarf2read.c (read_call_site_scope): Eliminate baseaddr.
---
gdb/block.c | 12 +++++++++++-
gdb/dwarf2loc.c | 7 ++++++-
gdb/dwarf2read.c | 7 ++-----
gdb/objfiles.c | 33 +++++++++++++++++++++++++++++++++
gdb/objfiles.h | 5 +++++
5 files changed, 57 insertions(+), 7 deletions(-)
diff --git a/gdb/block.c b/gdb/block.c
index 5c6faa8504..3113980259 100644
--- a/gdb/block.c
+++ b/gdb/block.c
@@ -226,7 +226,17 @@ call_site_for_pc (struct gdbarch *gdbarch, CORE_ADDR pc)
cust = find_pc_compunit_symtab (pc - 1);
if (cust != NULL && COMPUNIT_CALL_SITE_HTAB (cust) != NULL)
- slot = htab_find_slot (COMPUNIT_CALL_SITE_HTAB (cust), &pc, NO_INSERT);
+ {
+ struct obj_section *sec;
+ sec = find_pc_section (pc);
+ if (sec != NULL)
+ {
+ CORE_ADDR pc_unrelocated = pc - obj_section_offset (sec);
+ slot = htab_find_slot (COMPUNIT_CALL_SITE_HTAB (cust),
+ &pc_unrelocated, NO_INSERT);
+ }
+ }
+
if (slot == NULL)
{
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 63643cb45d..c936630e0c 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -855,7 +855,12 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
}
case FIELD_LOC_KIND_PHYSADDR:
- return FIELD_STATIC_PHYSADDR (call_site->target);
+ {
+ CORE_ADDR addr = FIELD_STATIC_PHYSADDR (call_site->target);
+ struct objfile *objfile
+ = call_site->per_cu->dwarf2_per_objfile->objfile;
+ return relocate_pc_addr (addr, objfile);
+ }
default:
internal_error (__FILE__, __LINE__, _("invalid call site target kind"));
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index de9755f6ce..6a8218dc61 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -13868,7 +13868,7 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
return;
}
pc = attr_value_as_address (attr) + baseaddr;
- pc = gdbarch_adjust_dwarf2_addr (gdbarch, pc);
+ pc = gdbarch_adjust_dwarf2_addr (gdbarch, pc) - baseaddr;
if (cu->call_site_htab == NULL)
cu->call_site_htab = htab_create_alloc_ex (16, core_addr_hash, core_addr_eq,
@@ -14019,10 +14019,7 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
"low pc, for referencing DIE %s [in module %s]"),
sect_offset_str (die->sect_off), objfile_name (objfile));
else
- {
- lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
- SET_FIELD_PHYSADDR (call_site->target, lowpc);
- }
+ SET_FIELD_PHYSADDR (call_site->target, lowpc);
}
}
else
diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 7cbcbbd01b..5e1c49c658 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -1493,3 +1493,36 @@ objfile_flavour_name (struct objfile *objfile)
return bfd_flavour_name (bfd_get_flavour (objfile->obfd));
return NULL;
}
+
+/* Return section of OBJFILE that contains unrelocated address ADDR. */
+
+static struct obj_section *
+find_objfile_section_for_unrelocated_addr (struct objfile *objfile,
+ CORE_ADDR addr)
+{
+ struct obj_section *osect;
+
+ if (objfile == NULL)
+ return NULL;
+
+ ALL_OBJFILE_OSECTIONS (objfile, osect)
+ {
+ if (obj_section_addr (osect) - obj_section_offset (osect) <= addr
+ && addr < obj_section_endaddr (osect) - obj_section_offset (osect))
+ return osect;
+ }
+
+ return NULL;
+}
+
+/* See objfiles.h. */
+
+CORE_ADDR
+relocate_pc_addr (CORE_ADDR addr, struct objfile *objfile)
+{
+ struct obj_section *sec
+ = find_objfile_section_for_unrelocated_addr (objfile, addr);
+ CORE_ADDR baseaddr = obj_section_offset (sec);
+ struct gdbarch *gdbarch = get_objfile_arch (objfile);
+ return gdbarch_adjust_dwarf2_addr (gdbarch, addr + baseaddr);
+}
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index 239aba2c2a..d4a9726b73 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -789,4 +789,9 @@ extern void objfile_register_static_link
extern const struct dynamic_prop *objfile_lookup_static_link
(struct objfile *objfile, const struct block *block);
+/* Given an unrelocated pc address ADDR belonging to a section of OBJFILE,
+ return the relocated address. */
+
+extern CORE_ADDR relocate_pc_addr (CORE_ADDR addr, struct objfile *objfile);
+
#endif /* !defined (OBJFILES_H) */