* [PATCH v6 00/10] GDB support for DW_AT_trampoline
@ 2024-03-28 12:05 Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 01/10] gdb, dwarf: add support for DW_AT_trampoline in DWARF reader Abdul Basit Ijaz
` (9 more replies)
0 siblings, 10 replies; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
please find attached a series of patches that attempts to enable GDB to handle the DW_AT_trampoline attribute on functions and inlined functions.
DW_AT_trampoline can be emitted by the compiler for functions that are compiler generated trampolines (e.g. wrapping other function calls).
In doing so, the compiler can specify a target as the value of DW_AT_trampoline which the trampoline is wrapping.
This series enables GDB to recognize the DW_AT_trampoline and store the target for a given function. Patch 3 adapts GDB's stepping behavior when dealing with trampolines and attempts to - by default - hide these trampolines from the user. When about to step into a trampoline, instead, GDB will try and step through the trampoline and directly towards the target. For rest of the patches as the name of the patch indicates it implements skipping of trampolines for the command mentioned in the patch name.
A new setting has also been introduced in this change to turn off this modified stepping behavior or printing of stack for trampolines.
The motivation for these patches comes from ifx which emits the attribute for some of its compiler generated functions. As I do not know of any other compiler (especially gcc/gfortran) emitting DW_AT_trampoline, I added a gdb.dwarf2 test to this series in order to test the trampoline handling within GDB.
Changes since V5:
* Updated the documentation part.
* Splitted the patch 4/4 for each command.
* Now trampolines are skipped for these commands as well as per
the feedback on V5 patch:
** backtrace -n,
** return
** mi commands -stack-list-frames and -stack-list-arguments
V5 series of patches can be found here:
https://sourceware.org/pipermail/gdb-patches/2023-August/201684.html
No regression seen on testing x64/native-extended-gdbserver(-m32)/x32/
native-gdbserver test configurations for these changes.
Thanks & Best Regards
Abdul Basit
Ijaz, Abdul B (7):
gdb: Skip trampoline frames for the backtrace command.
gdb: Skip trampoline functions for the finish and reverse-finish
commands.
gdb: Skip trampoline functions for the up command.
gdb: Skip trampoline functions for the return command.
gdb, mi: Skip trampoline functions for the -stack-list-frames command.
gdb, mi: Skip trampoline functions for the -stack-list-arguments
command.
gdb: Filter trampoline frames in backtrace when using Python
frame-filters.
Nils-Christian Kempke (3):
gdb, dwarf: add support for DW_AT_trampoline in DWARF reader
gdb/symtab: add lookup for trampoline functions
gdb: handle stepping through functions with DW_AT_trampoline
gdb/NEWS | 13 +
gdb/doc/gdb.texinfo | 53 +++-
gdb/dwarf2/read.c | 46 +++-
gdb/gdbtypes.c | 34 ++-
gdb/gdbtypes.h | 113 +++++++-
gdb/infcmd.c | 12 +
gdb/infrun.c | 95 ++++++-
gdb/infrun.h | 16 ++
gdb/mi/mi-cmd-stack.c | 14 +
gdb/python/py-frame.c | 11 +
gdb/stack.c | 26 ++
gdb/symtab.c | 81 ++++++
gdb/symtab.h | 19 ++
.../gdb.dwarf2/dw2-function-trampolines.c | 80 ++++++
.../gdb.dwarf2/dw2-function-trampolines.exp | 245 ++++++++++++++++++
gdb/testsuite/gdb.fortran/func-trampoline.exp | 102 ++++++++
gdb/testsuite/gdb.fortran/func-trampoline.f90 | 39 +++
.../gdb.fortran/mixed-lang-stack.exp | 10 +-
gdb/testsuite/gdb.mi/mi-func-trampoline.exp | 75 ++++++
.../gdb.python/py-framefilter-trampoline.exp | 77 ++++++
.../gdb.python/py-framefilter-trampoline.py | 31 +++
.../gdb.reverse/finish-reverse-trampoline.exp | 56 ++++
22 files changed, 1233 insertions(+), 15 deletions(-)
create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.c
create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.exp
create mode 100644 gdb/testsuite/gdb.fortran/func-trampoline.exp
create mode 100644 gdb/testsuite/gdb.fortran/func-trampoline.f90
create mode 100644 gdb/testsuite/gdb.mi/mi-func-trampoline.exp
create mode 100644 gdb/testsuite/gdb.python/py-framefilter-trampoline.exp
create mode 100644 gdb/testsuite/gdb.python/py-framefilter-trampoline.py
create mode 100644 gdb/testsuite/gdb.reverse/finish-reverse-trampoline.exp
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 01/10] gdb, dwarf: add support for DW_AT_trampoline in DWARF reader
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 02/10] gdb/symtab: add lookup for trampoline functions Abdul Basit Ijaz
` (8 subsequent siblings)
9 siblings, 0 replies; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches
Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz, Nils-Christian Kempke
From: Nils-Christian Kempke <nils-christian.kempke@intel.com>
DW_AT_trampoline can be used to describe compiler generated functions
that serve some intermediary purpose on making a call to another
function. A compiler can emit this tag in order to help a debugger hide
the trampolines from a user.
The attribute is only applicable to DW_TAG_subroutine and
DW_TAG_inlined_subroutine tags. It contains information about the
trampoline target either as a reference to its DIE, as its address or
its name. DW_AT_trampoline can also be a flag indicating that the DIE
is a trampoline or not without specifying the target (e.g. if it is
unknown).
This patch adds support to GDB for reading the DW_AT_trampoline
attribute. It stores the attribute and its value in the type_specific
part of a GDB type. This patch is implemented in preparation of the
following patches, which will add a mechanism to hide DW_AT_trampoline
subroutines from the user.
2024-03-28 Nils-Christian Kempke <nils-christian.kempke@intel.com>
---
gdb/dwarf2/read.c | 46 ++++++++++++++++++-
gdb/gdbtypes.c | 34 +++++++++++++-
gdb/gdbtypes.h | 113 ++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 186 insertions(+), 7 deletions(-)
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 31313bc88b3..6ab8a675018 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -14581,6 +14581,50 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu)
if (prototyped_function_p (die, cu))
ftype->set_is_prototyped (true);
+ /* If this is a trampoline function store it and its target here. */
+ attr = dwarf2_attr (die, DW_AT_trampoline, cu);
+ if (attr != nullptr)
+ {
+ TYPE_FUNC_FLAGS (ftype) |= FUNC_TYPE_TRAMPOLINE;
+ TYPE_TRAMPOLINE_TARGET (ftype)
+ = (trampoline_target *) TYPE_ZALLOC (ftype,
+ sizeof (trampoline_target));
+
+ /* A DW_AT_trampoline can be either an address, a flag, a reference or a
+ string. */
+ if (attr->form_is_string ())
+ TYPE_TRAMPOLINE_TARGET (ftype)->set_target_name
+ (attr->as_string ());
+ else if (attr->form_is_ref ())
+ {
+ die_info *target_die;
+ dwarf2_cu *target_cu = cu;
+ unrelocated_addr lowpc;
+
+ target_die = follow_die_ref (die, attr, &target_cu);
+
+ if (dwarf2_get_pc_bounds (target_die, &lowpc, NULL, target_cu,
+ nullptr, nullptr) <= PC_BOUNDS_INVALID)
+ complaint (_("DW_AT_trampoline target DIE has invalid "
+ "low pc, for referencing DIE %s[in module %s]"),
+ sect_offset_str (die->sect_off),
+ objfile_name (objfile));
+ else
+ {
+ lowpc = cu->per_objfile->adjust (lowpc);
+ TYPE_TRAMPOLINE_TARGET (ftype)->set_target_addr (lowpc);
+ }
+ }
+ else if (attr->form_is_unsigned ())
+ TYPE_TRAMPOLINE_TARGET (ftype)->set_target_flag (attr->as_boolean ());
+ else
+ {
+ unrelocated_addr target_addr = attr->as_address ();
+ target_addr = cu->per_objfile->adjust (target_addr);
+ TYPE_TRAMPOLINE_TARGET (ftype)->set_target_addr (target_addr);
+ }
+ }
+
/* Store the calling convention in the type if it's available in
the subroutine die. Otherwise set the calling convention to
the default value DW_CC_normal. */
@@ -14598,7 +14642,7 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu)
if the DWARF producer set that information. */
attr = dwarf2_attr (die, DW_AT_noreturn, cu);
if (attr && attr->as_boolean ())
- TYPE_NO_RETURN (ftype) = 1;
+ TYPE_FUNC_FLAGS (ftype) |= FUNC_TYPE_NO_RETURN;
/* We need to add the subroutine type to the die immediately so
we don't infinitely recurse when dealing with parameters
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 1e1a7e9ce61..cce45795d5a 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -5069,6 +5069,33 @@ print_fixed_point_type_info (struct type *type, int spaces)
type->fixed_point_scaling_factor ().str ().c_str ());
}
+/* Print the contents of the TYPE's self_trampoline_target, assuming that its
+ type-specific kind is TYPE_SPECIFIC_FUNC and is_trampoline is not 0. */
+static void
+print_trampoline_target_info (struct type *type, int spaces)
+{
+ switch (TYPE_TRAMPOLINE_TARGET (type)->target_kind ())
+ {
+ case TRAMPOLINE_TARGET_ADDR:
+ gdb_printf ("%*starget addr: 0x%s\n", spaces + 2, "",
+ print_core_address (type->arch_owner (),
+ (CORE_ADDR) TYPE_TRAMPOLINE_TARGET (type)
+ ->target_addr ()));
+ break;
+ case TRAMPOLINE_TARGET_NAME:
+ gdb_printf ("%*starget name: %s\n", spaces + 2, "",
+ TYPE_TRAMPOLINE_TARGET (type)->target_name ());
+ break;
+ case TRAMPOLINE_TARGET_FLAG:
+ gdb_printf ("%*starget flag: %d\n", spaces + 2, "",
+ TYPE_TRAMPOLINE_TARGET (type)->target_flag ());
+ break;
+ default:
+ gdb_assert_not_reached ("unhandled trampoline target kind");
+ break;
+ }
+}
+
static struct obstack dont_print_type_obstack;
/* Print the dynamic_prop PROP. */
@@ -5344,6 +5371,10 @@ recursive_dump_type (struct type *type, int spaces)
gdb_printf ("%*scalling_convention %d\n", spaces, "",
TYPE_CALLING_CONVENTION (type));
/* tail_call_list is not printed. */
+ gdb_printf ("%*sfunc_type_flags 0x%x\n", spaces, "",
+ (unsigned int) TYPE_FUNC_FLAGS (type));
+ if (TYPE_IS_TRAMPOLINE (type))
+ print_trampoline_target_info (type, spaces);
break;
case TYPE_SPECIFIC_SELF_TYPE:
@@ -5558,8 +5589,9 @@ copy_type_recursive (struct type *type, htab_t copied_types)
case TYPE_SPECIFIC_FUNC:
INIT_FUNC_SPECIFIC (new_type);
TYPE_CALLING_CONVENTION (new_type) = TYPE_CALLING_CONVENTION (type);
- TYPE_NO_RETURN (new_type) = TYPE_NO_RETURN (type);
+ TYPE_FUNC_FLAGS (new_type) = TYPE_FUNC_FLAGS (type);
TYPE_TAIL_CALL_LIST (new_type) = NULL;
+ TYPE_TRAMPOLINE_TARGET (new_type) = TYPE_TRAMPOLINE_TARGET (type);
break;
case TYPE_SPECIFIC_FLOATFORMAT:
TYPE_FLOATFORMAT (new_type) = TYPE_FLOATFORMAT (type);
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index f80bd7e071a..0cd4941e85b 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -97,6 +97,21 @@ enum type_instance_flag_value : unsigned
DEF_ENUM_FLAGS_TYPE (enum type_instance_flag_value, type_instance_flags);
+/* * Define flags for function types. */
+enum func_type_flag_value : unsigned
+{
+ /* * Flag indicates, whether this function normally returns to its
+ caller. It is set from the DW_AT_noreturn attribute if set on
+ the DW_TAG_subprogram. */
+ FUNC_TYPE_NO_RETURN = (1 << 0),
+
+ /* * Flag is used for functions marked with DW_AT_trampoline. These
+ are compiler generated wrappers that should be hidden from the user. */
+ FUNC_TYPE_TRAMPOLINE = (1 << 1)
+};
+
+DEF_ENUM_FLAGS_TYPE (enum func_type_flag_value, func_type_flags);
+
/* * Not textual. By default, GDB treats all single byte integers as
characters (or elements of strings) unless this flag is set. */
@@ -1812,11 +1827,9 @@ struct func_type
ENUM_BITFIELD (dwarf_calling_convention) calling_convention : 8;
- /* * Whether this function normally returns to its caller. It is
- set from the DW_AT_noreturn attribute if set on the
- DW_TAG_subprogram. */
+ /* * For storing function types defined in eunm func_type_flag_value. */
- unsigned int is_noreturn : 1;
+ func_type_flags flags;
/* * Only those DW_TAG_call_site's in this function that have
DW_AT_call_tail_call set are linked in this list. Function
@@ -1831,6 +1844,87 @@ struct func_type
contains the method. */
struct type *self_type;
+
+ struct trampoline_target *self_trampoline_target;
+ };
+
+/* The kind of location held by this call site target. */
+enum trampoline_target_kind
+ {
+ /* An address. */
+ TRAMPOLINE_TARGET_ADDR,
+ /* A (mangled) name. */
+ TRAMPOLINE_TARGET_NAME,
+ /* A flag (target is unknown). */
+ TRAMPOLINE_TARGET_FLAG,
+ };
+
+/* Target information for trampoline functions. */
+
+struct trampoline_target
+ {
+ /* Returns what kind of target the trampoline points to. */
+ trampoline_target_kind target_kind () const
+ {
+ return m_target_kind;
+ }
+
+ /* Set the address for trampoline target. */
+ void set_target_addr (unrelocated_addr unreloc_addr)
+ {
+ m_target_kind = TRAMPOLINE_TARGET_ADDR;
+ m_trampoline_target.unreloc_addr = unreloc_addr;
+ }
+
+ /* Return the address of the trampoline target. */
+ unrelocated_addr target_addr () const
+ {
+ gdb_assert (m_target_kind == TRAMPOLINE_TARGET_ADDR);
+ return m_trampoline_target.unreloc_addr;
+ }
+
+ /* Set the name of the trampoline target. */
+ void set_target_name (const char *name)
+ {
+ m_target_kind = TRAMPOLINE_TARGET_NAME;
+ m_trampoline_target.name = name;
+ }
+
+ /* Return the name of the trampoline target. */
+ const char *target_name () const
+ {
+ gdb_assert (m_target_kind == TRAMPOLINE_TARGET_NAME);
+ return m_trampoline_target.name;
+ }
+
+ /* Set the flag for trampoline target subroutine. */
+ void set_target_flag (bool flag)
+ {
+ m_target_kind = TRAMPOLINE_TARGET_FLAG;
+ m_trampoline_target.flag = flag;
+ }
+
+ /* Return the flag for trampoline target. */
+ bool target_flag () const
+ {
+ gdb_assert (m_target_kind == TRAMPOLINE_TARGET_FLAG);
+ return m_trampoline_target.flag;
+ }
+
+ private:
+
+ union
+ {
+ /* Address. */
+ unrelocated_addr unreloc_addr;
+ /* Mangled name. */
+ const char *name;
+ /* Flag. */
+ bool flag;
+ } m_trampoline_target;
+
+ /* * Discriminant for union m_trampoline_target. */
+ ENUM_BITFIELD (trampoline_target_kind) m_target_kind : 2;
};
/* The type-specific info for TYPE_CODE_FIXED_POINT types. */
@@ -1973,7 +2067,16 @@ extern void set_type_vptr_basetype (struct type *, struct type *);
#define TYPE_GNAT_SPECIFIC(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.gnat_stuff
#define TYPE_DESCRIPTIVE_TYPE(thistype) TYPE_GNAT_SPECIFIC(thistype)->descriptive_type
#define TYPE_CALLING_CONVENTION(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->calling_convention
-#define TYPE_NO_RETURN(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->is_noreturn
+#define TYPE_FUNC_FLAGS(thistype) \
+ TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->flags
+#define TYPE_NO_RETURN(thistype) \
+ (TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->flags \
+ & FUNC_TYPE_NO_RETURN)
+#define TYPE_IS_TRAMPOLINE(thistype) \
+ (TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->flags \
+ & FUNC_TYPE_TRAMPOLINE)
+#define TYPE_TRAMPOLINE_TARGET(thistype) \
+ TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->self_trampoline_target
#define TYPE_TAIL_CALL_LIST(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->tail_call_list
#define TYPE_BASECLASS(thistype,index) ((thistype)->field (index).type ())
#define TYPE_N_BASECLASSES(thistype) TYPE_CPLUS_SPECIFIC(thistype)->n_baseclasses
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 02/10] gdb/symtab: add lookup for trampoline functions
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 01/10] gdb, dwarf: add support for DW_AT_trampoline in DWARF reader Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline Abdul Basit Ijaz
` (7 subsequent siblings)
9 siblings, 0 replies; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches
Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz, Nils-Christian Kempke
From: Nils-Christian Kempke <nils-christian.kempke@intel.com>
In order to query information about the DW_AT_trampoline tag for
subroutines and inlined subroutines, two function were added to symtab.
First, a routine for querying whether the given pc belongs to a block
that is associated with a function (maybe inlined) marked
DW_AT_trampoline.
Second, a routine for querying a trampoline function's target.
Subroutines and inlined subroutines marked with DW_AT_trampoline usually
contain information about the target subroutine they are 'wrapping'/
passing control to.
2024-03-28 Nils-Christian Kempke <nils-christian.kempke@intel.com>
---
gdb/symtab.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/symtab.h | 14 +++++++++++
2 files changed, 83 insertions(+)
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 86603dfebc3..831a58a9aff 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -73,6 +73,7 @@
#include "gdbsupport/pathstuff.h"
#include "gdbsupport/common-utils.h"
#include <optional>
+#include "gdbsupport/symbol.h"
/* Forward declarations for local functions. */
@@ -4205,6 +4206,74 @@ find_function_alias_target (bound_minimal_symbol msymbol)
return NULL;
}
+/* See symtab.h. */
+
+bool
+in_trampoline_function (CORE_ADDR pc)
+{
+ /* Find the innermost function containing pc. This might be an inlined
+ function. */
+ symbol *sym = find_pc_sect_containing_function (pc,
+ find_pc_mapped_section (pc));
+ return sym != nullptr && TYPE_IS_TRAMPOLINE (sym->type ());
+}
+
+/* See symtab.h. */
+
+CORE_ADDR
+find_function_trampoline_target (CORE_ADDR pc)
+{
+ /* Find the innermost function containing pc. This might be an inlined
+ function. */
+ symbol *sym = find_pc_sect_containing_function (pc,
+ find_pc_mapped_section (pc));
+ CORE_ADDR target_address = 0;
+
+ if (sym != nullptr && TYPE_IS_TRAMPOLINE (sym->type ()))
+ {
+ trampoline_target *trampoline = TYPE_TRAMPOLINE_TARGET (sym->type ());
+
+ /* DW_AT_trampoline can be given as an address, name, or flag here (die
+ references have been resolved as names at this point. In the case
+ where DW_AT_trampoline contains a flag we do not know the target
+ address and return 0. */
+ if (trampoline->target_kind () == TRAMPOLINE_TARGET_NAME)
+ {
+ /* Handle both the mangled and demangled PHYSNAME. */
+ const char *physname = trampoline->target_name ();
+
+ /* First, check whether there exists a symbol matching the
+ physname. If we cannot find one also check for minimal
+ symbols. */
+ const block *blk = block_for_pc (pc);
+ struct block_symbol bs = lookup_symbol (physname, blk,
+ SEARCH_VAR_DOMAIN, 0);
+ if (bs.symbol != nullptr)
+ {
+ const struct block *block = bs.symbol->value_block ();
+ gdb_assert (block != nullptr);
+ target_address = block->start ();
+ }
+ else
+ {
+ if (find_minimal_symbol_address (physname, &target_address,
+ nullptr) != 0)
+ target_address = 0;
+ }
+ }
+ else if (trampoline->target_kind () == TRAMPOLINE_TARGET_ADDR)
+ {
+ /* If the function symbol containing this trampoline target has
+ been relocated we assume the target_address also needs relocation.
+ If it has not been relocated the offset should be zero. */
+ target_address = \
+ ( (CORE_ADDR) trampoline->target_addr ()
+ + sym->objfile ()->section_offsets[sym->section_index ()]);
+ }
+ }
+
+ return target_address;
+}
\f
/* If P is of the form "operator[ \t]+..." where `...' is
some legitimate operator text, return a pointer to the
diff --git a/gdb/symtab.h b/gdb/symtab.h
index bf9a3cfb79f..c60485dc6d3 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -2354,6 +2354,20 @@ extern const struct gnu_ifunc_fns *gnu_ifunc_fns_p;
extern CORE_ADDR find_solib_trampoline_target (const frame_info_ptr &, CORE_ADDR);
+/* Return whether or not the current pc is within a block that belongs to a
+ function that is marked as a trampoline by the compiler. */
+
+extern bool in_trampoline_function (CORE_ADDR pc);
+
+/* Find the target of a trampoline function marked via the DW_AT_trampoline
+ attribute and return its address. Returns 0 if the pc is not contained
+ in a trampoline function (inlined or not). If DW_AT_trampoline
+ is given as a flag, the target is unknown and the function will still return
+ 0. One has to additionally query in_trampoline_function to cover this
+ case. */
+
+extern CORE_ADDR find_function_trampoline_target (CORE_ADDR pc);
+
struct symtab_and_line
{
/* The program space of this sal. */
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 01/10] gdb, dwarf: add support for DW_AT_trampoline in DWARF reader Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 02/10] gdb/symtab: add lookup for trampoline functions Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 13:58 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 04/10] gdb: Skip trampoline frames for the backtrace command Abdul Basit Ijaz
` (6 subsequent siblings)
9 siblings, 1 reply; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches
Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz, Nils-Christian Kempke
From: Nils-Christian Kempke <nils-christian.kempke@intel.com>
This patch makes infrun continue stepping into and through trampoline
functions marked via the DW_AT_trampoline in DWARF. The attribute can
be emitted by the compiler for certain subroutines/inlined subroutines
that are compiler generated and should be hidden from a user.
Mainly, infrun is modified in 3 ways.
First, GDB will now attempt to step through trampoline functions.
Whenever we issued a step command that would make GDB step into a
function that is marked trampoline, GDB will try to step directly towards
the trampoline's 'target' instead and, e.g., not stop at the first
instruction of the trampoline.
The target can be specified by the compiler by the value of
DW_AT_trampoline if its form is either an address, a name, or a DIE
reference. DW_AT_trampoline is also allowed to be specified as a flag
(containing true or false), in which case the target is assumed to be
unknown. If GDB successfully finds a target, so if the value of
DW_AT_trampoline was not a flag and could be resolved successfully, GDB
steps directly towards the target and through the trampoline, hiding
the trampoline from the user. If GDB cannot, however deduce a target,
most likely because the DW_AT_trampoline was given as a flag or because
of broken debug info, it will instead continue inside execution in the
trampoline function until it reaches an instruction that is not
associated with a trampoline function, which is usually the target
function. It will then stop and give control back to the user.
It should be noted, that there might be the cases, where trampolines
call functions other than the target before the actual target call. If,
in such a situation, GDB fails to resolve the target, it would resume
execution until stepping into this other function call, and hand back
control to the user, without actually having reached the target. A
second step would have to be issued by the user to arrive a the target
(by resuming in the trampoline and then until leaving it a second time).
As this is a rather pathological case and no real instance of this is
known, I think the current behavior here is good enough and seems to be
the best GDB can do in such a situation.
Secondly, as trampoline functions normally do not have any real source
code correlation, it is likely that they mostly appear without line
info.
Normally, GDB would skip completely over a function call to a function
that has no source line information, so we would never get to the
aforementioned stepping through a trampoline and target resolution. To
remedy this, for debug info trampolines, GDB now attempts to step through
them regardless of them having source line information or not. So
issuing a step at a function call wrapped by a trampoline without source
line information will no longer skip the whole function call, but now
step through the trampoline and attempt to resolve the trampoline target
as described above (so usually, a single step at the call site will step
through the trampoline and towards the target, even if the trampoline had
not source line info).
Last, in all other cases when GDB is about to stop at a location that is
included in a trampoline region (e.g. after a step from the target back
into the trampoline) GDB will instead continue until the trampoline
region is left again and only then give control back to the user. This
change serves the purpose of allowing stepping back from a target call
through the trampoline without the user noticing the artificial function
call inbetween call site and target.
Together, these changes attempt to hide the trampoline function from the
user while stepping. Additionally, the skip-trampoline-functions option
has been introduced in infrun. It is set by default, and, when turned
off, GDB will return to its 'normal' stepping behavior and ignore any
possible DW_AT_trampoline.
As currently only ifx emits the DW_AT_trampoline tag, a test has been
added to gdb.dwarf2 that artificially creates a set of trampoline
functions.
gdb/ChangeLog:
2022-08-09 Nils-Christian Kempke <nils-christian.kempke@intel.com>
* NEWS: Add skip-trampoline-functions to 'New commands' section.
* infrun.c (skip_trampoline-functions): New static variable.
(process_event_stop_test): Step into/through trampolines.
(show_skip_trampoline_functions): New helper for the
skip-trampoline-functions setting.
(_initialize_infrun): Add skip-trampoline-functions setting.
gdb/doc/ChangeLog:
2022-08-09 Nils-Christian Kempke <nils-christian.kempke@intel.com>
* gdb.texinfo: Add section on skip-trampoline-functions setting.
gdb/testsuite/ChangeLog:
2022-08-09 Nils-Christian Kempke <nils-christian.kempke@intel.com>
* gdb.dwarf2/dw2-function-trampolines.c: New test source.
* gdb.dwarf2/dw2-function-trampolines.exp: New test case.
2024-03-28 Nils-Christian Kempke <nils-christian.kempke@intel.com>
---
gdb/NEWS | 11 +
gdb/doc/gdb.texinfo | 35 +++
gdb/infrun.c | 87 ++++++-
gdb/infrun.h | 5 +
.../gdb.dwarf2/dw2-function-trampolines.c | 80 ++++++
.../gdb.dwarf2/dw2-function-trampolines.exp | 245 ++++++++++++++++++
6 files changed, 459 insertions(+), 4 deletions(-)
create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.c
create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.exp
diff --git a/gdb/NEWS b/gdb/NEWS
index feb3a37393a..da0d936ff70 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -892,6 +892,17 @@ platform.
* New commands
+set skip-trampoline-functions on|off
+show skip-trampoline-functions
+ This setting is 'on' by default. When 'on' it controls whether GDB will
+ recognize function calls that have been marked as trampolines in the debug
+ info. It improves stepping behavior in that it steps over the trampoline
+ code and hides it from the user. Currently, only DWARF trampolines are
+ supported.
+
+ If this is turned off, GDB gdb will handle trampoline functions the same
+ as any other function.
+
maint set backtrace-on-fatal-signal on|off
maint show backtrace-on-fatal-signal
This setting is 'on' by default. When 'on' GDB will print a limited
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 727f9275bfb..19fecd00480 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -6445,6 +6445,41 @@ debug information. This is the default.
Show whether @value{GDBN} will stop in or step over functions without
source line debug information.
+@kindex set skip-trampoline-functions
+@item set skip-trampoline-functions
+@cindex trampoline functions
+@cindex stepping through trampoline functions
+@itemx set skip-trampoline-functions on
+When calling a function in any language, some compilers might generate
+so-called trampoline functions, which wrap the actual function call (the
+target of the trampoline). The compiler might mark such a trampoline in
+its debug information.
+
+The default is @code{on} and it will cause @value{GDBN} to treat these
+trampolines differently.
+
+When issuing a @code{step} at the call site of a trampoline function if
+@code{skip-trampoline-functions} is set @value{GDBN} will attempt to determine
+the target of the trampoline and then step through the trampoline stopping at
+the target. If the target could not be found or was not given in the debug
+info, @value{GDBN} will simply continue execution until it leaves the
+trampoline code, even if the trampoline has no line info associated with it.
+When returning from a target function call and stepping back into the
+trampoline, @value{GDBN} will step over the trampoline towards the call site.
+Additionally, even if stopped in a trampoline function with source
+line information, issuing a @code{step} will prompt @value{GDBN} to resume
+execution until leaving the trampoline region. The @code{stepi} command
+is not affected by the setting which is enabled by default. Currently, only
+DWARF trampolines marked via DW_AT_trampoline are supported by this.
+
+@item set skip-trampoline-functions off
+Causes @value{GDBN} to completely ignore any trampoline information a compiler
+might have emitted in its debug info. Trampolines will be treated like any
+other normal function.
+
+@item show skip-trampoline-functions
+Show whether @value{GDBN} tries to skip trampolines or not.
+
@kindex finish
@kindex fin @r{(@code{finish})}
@item finish
diff --git a/gdb/infrun.c b/gdb/infrun.c
index a5030b16376..a669798f5b8 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -187,6 +187,12 @@ get_previous_thread ()
static bool detach_fork = true;
+/* If set (default) GDB will step through functions/inlined subroutines marked
+ DW_AT_trampoline by the compiler. If false, GDB will ignore the
+ attribute. */
+
+static bool skip_trampoline_functions = true;
+
bool debug_infrun = false;
static void
show_debug_infrun (struct ui_file *file, int from_tty,
@@ -7863,7 +7869,6 @@ process_event_stop_test (struct execution_control_state *ecs)
!= find_pc_function (ecs->event_thread->stop_pc ())))))
{
CORE_ADDR stop_pc = ecs->event_thread->stop_pc ();
- CORE_ADDR real_stop_pc;
infrun_debug_printf ("stepped into subroutine");
@@ -7935,8 +7940,47 @@ process_event_stop_test (struct execution_control_state *ecs)
calling routine and the real function), locate the real
function. That's what tells us (a) whether we want to step
into it at all, and (b) what prologue we want to run to the
- end of, if we do step into it. */
- real_stop_pc = skip_language_trampoline (frame, stop_pc);
+ end of, if we do step into it. For functions marked as
+ trampoline functions we try to find their target and step
+ towards it (if skip_trampoline_functions is not set to false by the
+ user). If no target can be determined we just step into the
+ trampoline and hand control back to the user. */
+ CORE_ADDR real_stop_pc = 0;
+ bool in_trampoline = skip_trampoline_functions
+ && in_trampoline_function (stop_pc);
+
+ if (in_trampoline)
+ {
+ if (execution_direction == EXEC_REVERSE)
+ {
+ keep_going (ecs);
+ return;
+ }
+
+ real_stop_pc = find_function_trampoline_target (stop_pc);
+
+ for (int i = 0; i < MAX_TRAMPOLINE_CHAIN_SIZE
+ && in_trampoline_function (real_stop_pc); ++i)
+ {
+ real_stop_pc = find_function_trampoline_target (real_stop_pc);
+ /* Exit if find_function_trampoline_target failed to find the
+ trampoline target. Do not try to resolve the trampolines
+ in this case. */
+ if (real_stop_pc == 0x0)
+ break;
+ }
+
+ /* If we failed to find a target we will just single step in the
+ hope of leaving the trampoline again soon. */
+ if (real_stop_pc == 0x0)
+ {
+ keep_going (ecs);
+ return;
+ }
+ }
+
+ if (real_stop_pc == 0)
+ real_stop_pc = skip_language_trampoline (frame, stop_pc);
if (real_stop_pc == 0)
real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc);
if (real_stop_pc != 0)
@@ -7957,6 +8001,8 @@ process_event_stop_test (struct execution_control_state *ecs)
/* If we have line number information for the function we are
thinking of stepping into and the function isn't on the skip
list, step into it.
+ If we are about to step into a function marked trampoline with no
+ line number information, we still want to enter it here.
If there are several symtabs at that PC (e.g. with include
files), just want to know whether *any* of them have line
@@ -7965,7 +8011,9 @@ process_event_stop_test (struct execution_control_state *ecs)
struct symtab_and_line tmp_sal;
tmp_sal = find_pc_line (ecs->stop_func_start, 0);
- if (tmp_sal.line != 0
+ if ((tmp_sal.line != 0
+ || (skip_trampoline_functions
+ && in_trampoline_function (ecs->stop_func_start)))
&& !function_name_is_marked_for_skip (ecs->stop_func_name,
tmp_sal)
&& !inline_frame_is_marked_for_skip (true, ecs->event_thread))
@@ -8118,6 +8166,19 @@ process_event_stop_test (struct execution_control_state *ecs)
return;
}
+ /* If we ended up in a function trampoline without stepping into a new
+ function we are either in some inlined trampoline or returning through a
+ trampoline function. In either case we continue to single step until we
+ are out of the trampoline code again. This check has to be done before
+ stop_pc_sal.line == 0 below, as trampolines usually don't have source
+ line information associated with them. */
+ if (skip_trampoline_functions && in_trampoline_function (stop_pc_sal.pc))
+ {
+ infrun_debug_printf ("stepped into trampoline code");
+ keep_going (ecs);
+ return;
+ }
+
if (stop_pc_sal.line == 0)
{
/* We have no line number information. That means to stop
@@ -10391,6 +10452,14 @@ show_exec_direction_func (struct ui_file *out, int from_tty,
}
}
+static void
+show_skip_trampoline_functions (ui_file *file, int from_tty,
+ cmd_list_element *c,
+ const char *value)
+{
+ gdb_printf (file, _("Skipping trampoline functions is %s.\n"), value);
+}
+
static void
show_schedule_multiple (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
@@ -10736,6 +10805,16 @@ Options are 'forward' or 'reverse'."),
set_exec_direction_func, show_exec_direction_func,
&setlist, &showlist);
+ add_setshow_boolean_cmd ("skip-trampoline-functions", class_run,
+ &skip_trampoline_functions, _("\
+Set whether gdb attempts to hide trampolines marked in the debug info."), _("\
+Show whether gdb attempts to hide trampolines marked in the debug info."), _("\
+If on, while stepping gdb will skip through functions and inlined functions\n\
+marked as trampolines by the compiler. If off, gdb will ignore such function\n\
+trampolines."),
+ nullptr, show_skip_trampoline_functions, &setlist,
+ &showlist);
+
/* Set/show detach-on-fork: user-settable mode. */
add_setshow_boolean_cmd ("detach-on-fork", class_run, &detach_fork, _("\
diff --git a/gdb/infrun.h b/gdb/infrun.h
index 5f83ca2b4c3..ea1ec134c7c 100644
--- a/gdb/infrun.h
+++ b/gdb/infrun.h
@@ -76,6 +76,11 @@ infrun_debug_show_threads (const char *title, ThreadRange threads)
}
+/* Maximum size of trampoline chain to process while resolving
+ trampolines. This avoids infinite loops for malformed debug
+ information. */
+#define MAX_TRAMPOLINE_CHAIN_SIZE 10
+
/* Nonzero if we want to give control to the user when we're notified
of shared library events by the dynamic linker. */
extern int stop_on_solib_events;
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.c b/gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.c
new file mode 100644
index 00000000000..0336710e130
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.c
@@ -0,0 +1,80 @@
+/* Copyright 2022 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* This test relies on inlined_trampoline being inlined into main and the other
+ functions not. All functions except target will be marked via
+ DW_AT_trampoline in the debug info and we'll check whether one can step
+ through the trampolines towards target. */
+volatile int global_var;
+
+int __attribute__ ((noinline))
+target () /* target decl line */
+{ /* target prologue */
+ asm ("target_label: .globl target_label");
+ ++global_var; /* target add */
+ asm ("target_label2: .globl target_label2");
+ return 9 + 10; /* target return */
+} /* target end */
+
+int __attribute__ ((noinline))
+trampoline ()
+{ /* trampoline prologue */
+ asm ("trampoline_label: .globl trampoline_label");
+ ++global_var;
+ return target (); /* trampoline target call */
+} /* trampoline end */
+
+static inline int __attribute__ ((always_inline))
+inlined_trampoline ()
+{ /* inlined_trampoline prologue */
+ asm ("inlined_trampoline_label: .globl inlined_trampoline_label");
+ ++global_var; /* inlined_trampoline add */
+ asm ("inlined_trampoline_label2: .globl inlined_trampoline_label2");
+ return target (); /* inlined_trampoline target call */
+} /* inlined_trampoline end */
+
+int __attribute__ ((noinline))
+chained_trampoline ()
+{ /* chained_trampoline prologue */
+ asm ("chained_trampoline_label: .globl chained_trampoline_label");
+ ++global_var;
+ return trampoline (); /* chained_trampoline trampoline call */
+} /* chained_trampoline end */
+
+int __attribute__ ((noinline))
+doubly_chained_trampoline ()
+{ /* doubly_chained_trampoline prologue */
+ asm ("doubly_chained_trampoline_label: .globl doubly_chained_trampoline_label");
+ ++global_var;
+ return chained_trampoline (); /* doubly_chained_trampoline chained_trampoline call */
+} /* doubly_chained_trampoline end */
+
+int
+main () /* main decl line */
+{ /* main prologue */
+ int ans;
+ asm ("main_label: .globl main_label");
+ global_var = 0; /* main set global_var */
+ asm ("main_label2: .globl main_label2");
+ ans = inlined_trampoline (); /* main call inlined_trampoline */
+ asm ("main_label3: .globl main_label3");
+ ans = trampoline (); /* main call trampoline */
+ asm ("main_label4: .globl main_label4");
+ ans = chained_trampoline (); /* main call chained_trampoline */
+ asm ("main_label5: .globl main_label5");
+ ans = doubly_chained_trampoline (); /* main call doubly_chained_trampoline */
+ asm ("main_label6: .globl main_label6");
+ return ans; /* main call return */
+} /* main end */
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.exp b/gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.exp
new file mode 100644
index 00000000000..0d1126c226c
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.exp
@@ -0,0 +1,245 @@
+# Copyright 2019-2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This test checks GDB's handling of functions/inlined functions marked
+# DW_AT_trampoline by the compiler. A function marked as trampoline should
+# generally be hidden from the user. We check whether we can step through
+# trampolines. Every trampoline is defined using a different type for its
+# target: a string, an address, a DIE reference or a flag.
+# Setting skip-trampoline-functions to false inside GDB should make it return
+# to its 'normal' behavior, ignore the DW_AT_trampoline, and skip all of the
+# non-inlined trampoline calls (as their DIEs don't have any source
+# information).
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+ return 0
+}
+
+standard_testfile .c .S
+
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+ global srcdir subdir srcfile
+ declare_labels lines_label trampoline_label
+
+ get_func_info target
+ get_func_info trampoline
+ get_func_info chained_trampoline
+ get_func_info doubly_chained_trampoline
+ get_func_info main
+
+ set target_decl_line [gdb_get_line_number "target decl line"]
+ set main_decl_line [gdb_get_line_number "main decl line"]
+ set main_call_inlined_trampoline_line [gdb_get_line_number "main call inlined_trampoline"]
+
+ cu {} {
+ compile_unit {
+ {language @DW_LANG_C}
+ {name dw2-function-trampolines.c}
+ {low_pc 0 addr}
+ {stmt_list ${lines_label} DW_FORM_sec_offset}
+ } {
+ subprogram {
+ {name target}
+ {low_pc $target_start addr}
+ {high_pc "$target_start + $target_len" addr}
+ {decl_file 1 data1}
+ {decl_line $target_decl_line data1}
+ }
+ # The 'trampoline' subprogram declares its target by name.
+ trampoline_label: subprogram {
+ {name trampoline}
+ {low_pc $trampoline_start addr}
+ {high_pc "$trampoline_start + $trampoline_len" addr}
+ {trampoline target string}
+ }
+ # The 'chained_trampoline' subprogram declares its target as die
+ # reference.
+ subprogram {
+ {name chained_trampoline}
+ {low_pc $chained_trampoline_start addr}
+ {high_pc "$chained_trampoline_start + $chained_trampoline_len" addr}
+ {trampoline %$trampoline_label}
+ }
+ # The 'doubly_chained_trampoline' subprogram declares no target.
+ # Its DW_AT_trampoline is a flag set to true.
+ subprogram {
+ {name doubly_chained_trampoline}
+ {low_pc $doubly_chained_trampoline_start addr}
+ {high_pc "$doubly_chained_trampoline_start + $doubly_chained_trampoline_len" addr}
+ {trampoline 1 flag}
+ }
+ subprogram {
+ {external 1 flag}
+ {name main}
+ {main_subprogram 1 flag}
+ {low_pc $main_start addr}
+ {high_pc "$main_start + $main_len" addr}
+ {decl_file 1 data1}
+ {decl_line $main_decl_line data1}
+ } {
+ # The 'inlined_trampoline' subroutine declares its target as
+ # an address.
+ inlined_subroutine {
+ {name inlined_trampoline}
+ {low_pc main_label2 addr}
+ {high_pc main_label3 addr}
+ {trampoline $target_start addr}
+ {call_file 1 data1}
+ {call_line $main_call_inlined_trampoline_line data1}
+ }
+ }
+ }
+ }
+
+ lines {version 2} lines_label {
+ include_dir "${srcdir}/${subdir}"
+ file_name "$srcfile" 1
+
+ program {
+ DW_LNE_set_address $main_start
+ line [gdb_get_line_number "main set global_var"]
+ DW_LNS_copy
+ DW_LNE_set_address main_label
+ line [gdb_get_line_number "main set global_var"]
+ DW_LNS_copy
+ DW_LNE_set_address main_label2
+ line [gdb_get_line_number "main call inlined_trampoline"]
+ DW_LNS_copy
+ DW_LNE_set_address inlined_trampoline_label
+ line [gdb_get_line_number "inlined_trampoline add"]
+ DW_LNS_copy
+ DW_LNE_set_address inlined_trampoline_label2
+ line [gdb_get_line_number "inlined_trampoline target call"]
+ DW_LNS_copy
+ DW_LNE_set_address main_label3
+ line [gdb_get_line_number "main call trampoline"]
+ DW_LNS_copy
+ DW_LNE_set_address main_label4
+ line [gdb_get_line_number "main call chained_trampoline"]
+ DW_LNS_copy
+ DW_LNE_set_address main_label5
+ line [gdb_get_line_number "main call doubly_chained_trampoline"]
+ DW_LNS_copy
+ DW_LNE_set_address main_label6
+ line [gdb_get_line_number "main call return"]
+ DW_LNS_copy
+ DW_LNE_set_address $main_end
+ DW_LNE_end_sequence
+
+ DW_LNE_set_address $target_start
+ line [gdb_get_line_number "target prologue"]
+ DW_LNS_negate_stmt
+ DW_LNS_copy
+ DW_LNE_set_address target_label
+ line [gdb_get_line_number "target add"]
+ DW_LNS_negate_stmt
+ DW_LNS_copy
+ DW_LNE_set_address target_label2
+ line [gdb_get_line_number "target return"]
+ DW_LNS_copy
+ DW_LNE_set_address $target_end
+ DW_LNE_end_sequence
+ }
+ }
+}
+
+if {[prepare_for_testing "failed to prepare" ${testfile} \
+ [list $srcfile $asm_file] {nodebug additional_flags=-O0}]} {
+ return -1
+}
+
+set target_first_line_pattern ".*target add.*"
+set target_second_line_pattern ".*target return.*"
+
+if ![runto_main] {
+ return -1
+}
+
+gdb_test "show skip-trampoline-functions" \
+ "Skipping trampoline functions is on\." \
+ "check skip-trampoline-functions is enabled"
+
+with_test_prefix "with trampoline handling" {
+ foreach {trampoline return_line} { "inlined_trampoline" "trampoline" \
+ "trampoline" "chained_trampoline" \
+ "chained_trampoline" "doubly_chained_trampoline" } {
+
+ gdb_test "s" "$target_first_line_pattern" "step through $trampoline"
+ gdb_test "s" "$target_second_line_pattern" \
+ "step target second line from $trampoline"
+ gdb_test "s" ".*main call $return_line.*" \
+ "step back through $trampoline"
+ }
+
+ # The doubly_chained_trampoline has only been marked as trampoline but no
+ # target was given. In this case GDB steps into the trampoline and then
+ # continues until the trampoline section is left again.
+
+ # When compiled with gcc 7.5 (and possibly others) on a 32 bit system, the
+ # trampoline function contains a call to __x86.get_pc_thunk.ax before the
+ # actual target call. So, we end up in __x86.get_pc_thunk.ax. Issuing a
+ # second step command will return from the function call back into the
+ # trampoline and go on inside the trampoline towards the actual target call.
+ # On other targets we step directly towards the target call.
+ gdb_test_multiple "s" "step through double_chained_trampoline" {
+ -re -wrap "$target_first_line_pattern" {
+ pass $gdb_test_name
+ }
+ -re -wrap ".*__x86.get_pc_thunk.ax.*" {
+ gdb_test "s" "$target_first_line_pattern" \
+ "step through double_chained_trampoline 2nd try"
+ }
+ }
+ gdb_test "s" "$target_second_line_pattern" \
+ "step target second line fromdoubly_chained_trampoline"
+ gdb_test "s" ".*main call return.*" \
+ "step back through doubly_chained_trampoline"
+}
+
+clean_restart ${testfile}
+
+if ![runto_main] {
+ return -1
+}
+
+gdb_test_no_output "set skip-trampoline-functions off" \
+ "disable trampoline handling"
+gdb_test "show skip-trampoline-functions" \
+ "Skipping trampoline functions is off." \
+ "check skip-trampoline-functions is disabled"
+
+with_test_prefix "without trampoline handling" {
+ gdb_test "s" ".*main call inlined_trampoline.*"
+ gdb_test "s" ".*inlined_trampoline add.*" \
+ "step into inlined_trampoline with skip-trampoline off"
+ gdb_test "s" ".*inlined_trampoline target call.*" \
+ "step in inlined_trampoline with skip-trampoline off"
+ gdb_test "s" "$target_first_line_pattern" \
+ "step into target with skip-trampoline off"
+ gdb_test "s" "$target_second_line_pattern" \
+ "step second line in target with skip-trampoline off"
+ gdb_test "s" ".*main call trampoline.*" \
+ "step brack from target with skip-trampoline off"
+ gdb_test "s" ".*main call chained_trampoline.*" \
+ "skip trampoline call with no line info"
+ gdb_test "s" ".*main call doubly_chained_trampoline.*" \
+ "skip chained_trampoline call with no line info"
+ gdb_test "s" ".*main call return.*" \
+ "skip doubly_chained_trampoline call with no line info"
+}
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 04/10] gdb: Skip trampoline frames for the backtrace command.
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
` (2 preceding siblings ...)
2024-03-28 12:05 ` [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 05/10] gdb: Skip trampoline functions for the finish and reverse-finish commands Abdul Basit Ijaz
` (5 subsequent siblings)
9 siblings, 0 replies; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
This change filters trampoline functions when the option
'skip-trampoline-functions' is set to 'on' for the backtrace command.
Before the change, GDB prints the frames indicated by the compiler with
DIE "DW_AT_trampoline" in the backtrace, but for better user experience,
all such frames can be hidden from the user.
The test 'gdb.fortran/mixed-lang-stack' test used to fail for the IFX
compiler because of extra trampoline frames in the backtrace. After the
commit, those trampoline frames are filtered and test is updated accordingly.
Extra trampoline frames:
bt -frame-arguments all
'''
\#8 0x0000000000405535 in mixed_func_1b_.t86p.t87p.t88p.t89p.t90p.t91p.t3v ()
\#10 0x0000000000405439 in mixed_func_1a_.void () at mixed-lang-stack.f90:33
'''
(gdb) FAIL: gdb.fortran/mixed-lang-stack.exp: lang=auto: bt -frame-arguments all
In this example the IFX compiler emits "DW_AT_trampoline" tag for the 'first'
and 'second' trampoline functions like following:
function second (x, y) result(z)
integer, intent(in) :: x, y
integer :: z
z = x * y ! breakpt-backtrace
end function second
function first (num1, num2) result(total)
integer, intent(in) :: num1, num2
integer :: total
total = second (num1 + 4, num2 * 3) ! first-breakpt
total = total + 30
end function first
Related Dwarf:
0x0000013f: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000404350)
DW_AT_high_pc (0x000000000040435f)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("second_.t74p.t75p")
DW_AT_name ("second_.t74p.t75p")
DW_AT_trampoline ("second_")
0x0000015a: DW_TAG_subprogram
DW_AT_low_pc (0x00000000004044a0)
DW_AT_high_pc (0x00000000004044af)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("first_.t104p.t105p")
DW_AT_name ("first_.t104p.t105p")
DW_AT_trampoline ("first_")
Before this change, the backtrace command output looks like:
'''
(gdb) backtrace 3
\#0 second (x=20, y=9) at test.f90:4
\#1 0x0000000000405209 in second_.t74p.t75p () at test.f90:12
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
(gdb) backtrace -3
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
\#3 0x0000000000405309 in first_.t95p.t96p () at test.f90:21
\#4 0x0000000000405234 in func_trampoline () at test.f90:17
'''
After the change:
'''
(gdb) backtrace 3
\#0 second (x=20, y=9) at test.f90:4
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
\#4 0x0000000000405234 in func_trampoline () at test.f90:17
(gdb) backtrace -3
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
\#4 0x0000000000405234 in func_trampoline () at test.f90:17
'''
The test gdb.fortran/func-trampoline.exp is added for testing the change.
2024-03-28 Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
---
gdb/NEWS | 5 +-
gdb/doc/gdb.texinfo | 6 ++
gdb/infrun.c | 8 +-
gdb/infrun.h | 6 ++
gdb/stack.c | 8 ++
gdb/symtab.c | 12 +++
gdb/symtab.h | 5 ++
gdb/testsuite/gdb.fortran/func-trampoline.exp | 77 +++++++++++++++++++
gdb/testsuite/gdb.fortran/func-trampoline.f90 | 39 ++++++++++
.../gdb.fortran/mixed-lang-stack.exp | 10 ++-
10 files changed, 167 insertions(+), 9 deletions(-)
create mode 100644 gdb/testsuite/gdb.fortran/func-trampoline.exp
create mode 100644 gdb/testsuite/gdb.fortran/func-trampoline.f90
diff --git a/gdb/NEWS b/gdb/NEWS
index da0d936ff70..025f2e1a17e 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -897,8 +897,9 @@ show skip-trampoline-functions
This setting is 'on' by default. When 'on' it controls whether GDB will
recognize function calls that have been marked as trampolines in the debug
info. It improves stepping behavior in that it steps over the trampoline
- code and hides it from the user. Currently, only DWARF trampolines are
- supported.
+ code and hides it from the user. It improves the printing of the stack by
+ hiding trampoline functions from the backtrace. Currently, only DWARF
+ trampolines are supported.
If this is turned off, GDB gdb will handle trampoline functions the same
as any other function.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 19fecd00480..6117f6e889f 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -6472,6 +6472,12 @@ execution until leaving the trampoline region. The @code{stepi} command
is not affected by the setting which is enabled by default. Currently, only
DWARF trampolines marked via DW_AT_trampoline are supported by this.
+When issuing a @code{backtrace}, if @code{skip-trampoline-functions} is set,
+@value{GDBN} will skip trampoline frames while printing the stack.
+
+Currently, only DWARF trampolines marked via DW_AT_trampoline are supported by
+this.
+
@item set skip-trampoline-functions off
Causes @value{GDBN} to completely ignore any trampoline information a compiler
might have emitted in its debug info. Trampolines will be treated like any
diff --git a/gdb/infrun.c b/gdb/infrun.c
index a669798f5b8..1c5711b8c41 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -191,7 +191,7 @@ static bool detach_fork = true;
DW_AT_trampoline by the compiler. If false, GDB will ignore the
attribute. */
-static bool skip_trampoline_functions = true;
+bool skip_trampoline_functions = true;
bool debug_infrun = false;
static void
@@ -10809,9 +10809,9 @@ Options are 'forward' or 'reverse'."),
&skip_trampoline_functions, _("\
Set whether gdb attempts to hide trampolines marked in the debug info."), _("\
Show whether gdb attempts to hide trampolines marked in the debug info."), _("\
-If on, while stepping gdb will skip through functions and inlined functions\n\
-marked as trampolines by the compiler. If off, gdb will ignore such function\n\
-trampolines."),
+If on, gdb will skip through functions and inlined functions marked as\n\
+trampolines by the compiler. If off, gdb will handle trampoline functions\n\
+the same way as any other function."),
nullptr, show_skip_trampoline_functions, &setlist,
&showlist);
diff --git a/gdb/infrun.h b/gdb/infrun.h
index ea1ec134c7c..fbe88ad4595 100644
--- a/gdb/infrun.h
+++ b/gdb/infrun.h
@@ -107,6 +107,12 @@ extern bool non_stop;
starting an inferior. */
extern bool disable_randomization;
+/* If set (default) GDB will step through functions/inlined subroutines marked
+ DW_AT_trampoline by the compiler. If false, GDB will ignore the
+ attribute. */
+
+extern bool skip_trampoline_functions;
+
/* Returns a unique identifier for the current stop. This can be used
to tell whether a command has proceeded the inferior past the
current location. */
diff --git a/gdb/stack.c b/gdb/stack.c
index 9c679222708..6a25054673f 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -2065,6 +2065,14 @@ backtrace_command_1 (const frame_print_options &fp_opts,
{
QUIT;
+ if (skip_trampoline_functions && in_trampoline_frame (fi))
+ {
+ /* Trampoline frames are not printed so they are not counted in
+ the backtrace limit. */
+ count++;
+ continue;
+ }
+
/* Don't use print_stack_frame; if an error() occurs it probably
means further attempts to backtrace would fail (on the other
hand, perhaps the code does or could be fixed to make sure
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 831a58a9aff..8f509663d9f 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -4220,6 +4220,18 @@ in_trampoline_function (CORE_ADDR pc)
/* See symtab.h. */
+bool
+in_trampoline_frame (frame_info_ptr fi)
+{
+ CORE_ADDR pc;
+ if (get_frame_pc_if_available (fi, &pc))
+ return in_trampoline_function (pc);
+
+ return false;
+}
+
+/* See symtab.h. */
+
CORE_ADDR
find_function_trampoline_target (CORE_ADDR pc)
{
diff --git a/gdb/symtab.h b/gdb/symtab.h
index c60485dc6d3..234171ed404 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -2359,6 +2359,11 @@ extern CORE_ADDR find_solib_trampoline_target (const frame_info_ptr &, CORE_ADDR
extern bool in_trampoline_function (CORE_ADDR pc);
+/* Return whether or not the pc of the current frame is within a block that
+ belongs to a function that is marked as a trampoline by the compiler. */
+
+extern bool in_trampoline_frame (frame_info_ptr);
+
/* Find the target of a trampoline function marked via the DW_AT_trampoline
attribute and return its address. Returns 0 if the pc is not contained
in a trampoline function (inlined or not). If DW_AT_trampoline
diff --git a/gdb/testsuite/gdb.fortran/func-trampoline.exp b/gdb/testsuite/gdb.fortran/func-trampoline.exp
new file mode 100644
index 00000000000..bfa0002cf0e
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/func-trampoline.exp
@@ -0,0 +1,77 @@
+# Copyright 2024 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/> .
+
+# Test "backtrace" and "backtrace -n" commands for functions with trampoline
+# calls.
+
+require allow_fortran_tests
+
+if {![test_compiler_info {ifx-*} f90]} {
+ untested "This test is only applicable for IFX, which emits the\
+ trampoline DIE in Dwarf."
+ return -1
+}
+
+standard_testfile ".f90"
+load_lib fortran.exp
+
+# Initialize the test by running the program to the innermost
+# function name "second".
+
+proc init_test {} {
+ global binfile srcfile inner_loc
+
+ clean_restart ${binfile}
+ if {![fortran_runto_main]} {
+ return -1
+ }
+
+ # Set breakpoint inside the innermost function 'second'.
+ gdb_breakpoint "$srcfile:$inner_loc"
+ gdb_continue_to_breakpoint "innermost-body" ".*$srcfile:$inner_loc.*"
+}
+
+if {[build_executable "failed to prepare" ${testfile} ${srcfile} \
+ {debug f90}]} {
+ return -1
+}
+
+set inner_loc [gdb_get_line_number "second-breakpt"]
+set middle_loc [gdb_get_line_number "first-breakpt"]
+set outer_loc [gdb_get_line_number "main-outer-loc"]
+set fill "\[^\r\n\]*"
+
+set inner_desc "second \\(x=20, y=9\\) at ${fill}$srcfile:$inner_loc"
+set middle_desc "first \\(num1=16, num2=3\\) at ${fill}$srcfile:$middle_loc"
+set outer_desc ".* at .*$srcfile:$outer_loc"
+
+with_test_prefix "backtrace" {
+ init_test
+
+ # Limit the backtrace to 3 frames and ensure both frames for first
+ # and second function are shown only and trampoline frames are filtered.
+ gdb_test "backtrace 3" [multi_line \
+ "#$decimal.* $inner_desc" \
+ "#$decimal.* $middle_desc" \
+ "#$decimal.* $outer_desc.*"]
+}
+
+with_test_prefix "backtrace outerframes" {
+ init_test
+
+ gdb_test "backtrace -3" [multi_line \
+ "#$decimal.* $middle_desc" \
+ "#$decimal.* $outer_desc.*"]
+}
diff --git a/gdb/testsuite/gdb.fortran/func-trampoline.f90 b/gdb/testsuite/gdb.fortran/func-trampoline.f90
new file mode 100644
index 00000000000..10eb3f5188f
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/func-trampoline.f90
@@ -0,0 +1,39 @@
+! Copyright 2024 Free Software Foundation, Inc.
+!
+! This program is free software; you can redistribute it and/or modify
+! it under the terms of the GNU General Public License as published by
+! the Free Software Foundation; either version 3 of the License, or
+! (at your option) any later version.
+!
+! This program is distributed in the hope that it will be useful,
+! but WITHOUT ANY WARRANTY; without even the implied warranty of
+! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+! GNU General Public License for more details.
+!
+! You should have received a copy of the GNU General Public License
+! along with this program. If not, see <http://www.gnu.org/licenses/> .
+
+! Source code for func-trampoline.exp.
+
+integer(kind=4) function second(x, y)
+ integer(kind=4), intent(in) :: x
+ integer(kind=4), intent(in) :: y
+
+ second = x * y ! second-breakpt
+end function
+
+integer(kind=4) function first(num1, num2)
+ integer(kind=4), intent(in) :: num1
+ integer(kind=4), intent(in) :: num2
+
+ first = second (num1 + 4, num2 * 3) ! first-breakpt
+end function
+
+program func_trampoline
+ integer(kind=4) :: total
+
+ total = first(16, 3) ! main-outer-loc
+
+ write(*,*) "Result is ", total, "\n"
+ ! Expected: 180
+end program func_trampoline
diff --git a/gdb/testsuite/gdb.fortran/mixed-lang-stack.exp b/gdb/testsuite/gdb.fortran/mixed-lang-stack.exp
index eef84da0e44..4591880ca7b 100644
--- a/gdb/testsuite/gdb.fortran/mixed-lang-stack.exp
+++ b/gdb/testsuite/gdb.fortran/mixed-lang-stack.exp
@@ -41,7 +41,7 @@ set have_index [exec_has_index_section $binfile]
# value to pass to GDB's 'set language ...' command.
proc run_tests { lang } {
with_test_prefix "lang=${lang}" {
- global binfile hex have_index
+ global binfile hex have_index decimal
clean_restart ${binfile}
@@ -63,6 +63,10 @@ proc run_tests { lang } {
set e_arg "\['\"\]abcdef\['\"\]"
set 1b_args "\[^\r\n\]+$e_arg\[^\r\n\]+"
set 1g_args "obj=\[^\r\n\]+"
+ # Generic decimal number is checked in regex for Frame #8 and #9 to
+ # handle filtered trampoline frames. Since Frame#8 and Frame#10 are
+ # set to trampoline in DWARF by Intel® Fortran Compiler (ifx), they
+ # are not shown by the backtrace command.
set bt_stack \
[multi_line \
"#0\\s+breakpt \\(\\) at \[^\r\n\]+" \
@@ -73,8 +77,8 @@ proc run_tests { lang } {
"#5\\s+$hex in mixed_func_1d \\(\[^\r\n\]+\\) at \[^\r\n\]+" \
"#6\\s+$hex in mixed_func_1c \\(\[^\r\n\]+\\) at \[^\r\n\]+" \
"#7\\s+$hex in mixed_func_1b \\($1b_args\\) at \[^\r\n\]+" \
- "#8\\s+$hex in mixed_func_1a \\(\\) at \[^\r\n\]+" \
- "#9\\s+$hex in mixed_stack_main \\(\\) at \[^\r\n\]+" ]
+ "#$decimal\\s+$hex in mixed_func_1a \\(\\) at \[^\r\n\]+" \
+ "#$decimal\\s+$hex in mixed_stack_main \\(\\) at \[^\r\n\]+" ]
set main_args "argc=1, argv=${hex}( \[^\r\n\]+)?"
set bt_stack_kfail \
[multi_line \
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 05/10] gdb: Skip trampoline functions for the finish and reverse-finish commands.
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
` (3 preceding siblings ...)
2024-03-28 12:05 ` [PATCH v6 04/10] gdb: Skip trampoline frames for the backtrace command Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 13:59 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 06/10] gdb: Skip trampoline functions for the up command Abdul Basit Ijaz
` (4 subsequent siblings)
9 siblings, 1 reply; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
This change skips trampoline functions when the option
'skip-trampoline-functions' is set to 'on' for the finish or reverse-finish
command. Before this change, for these commands GDB returns to the trampoline
function indicated by the compiler with DIE "DW_AT_trampoline". For better
user experience, all such frames can be hidden from the user.
In this example the IFX compiler emits "DW_AT_trampoline" tag for the 'first'
and 'second' trampoline functions like following:
function second (x, y) result(z)
integer, intent(in) :: x, y
integer :: z
z = x * y ! breakpt-finish
end function second
function first (num1, num2) result(total)
integer, intent(in) :: num1, num2
integer :: total
total = second (num1 + 4, num2 * 3) ! first-breakpt
total = total + 30
end function first
Related Dwarf:
0x0000013f: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000404350)
DW_AT_high_pc (0x000000000040435f)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("second_.t74p.t75p")
DW_AT_name ("second_.t74p.t75p")
DW_AT_trampoline ("second_")
0x0000015a: DW_TAG_subprogram
DW_AT_low_pc (0x00000000004044a0)
DW_AT_high_pc (0x00000000004044af)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("first_.t104p.t105p")
DW_AT_name ("first_.t104p.t105p")
DW_AT_trampoline ("first_")
Before this change, the finish command output looks like:
'''
(gdb) finish
Run till exit from #0 second (x=20, y=9) at test.f90:4
0x0000000000405209 in second_.t74p.t75p () at test.f90:12
12 end function first
Value returned is $1 = 180
'''
The reverse-finish command output in this test before the change:
'''
(gdb) reverse-finish
Run back to call of #0 second (x=20, y=9) at test.f90:4
0x0000000000405204 in second_.t74p.t75p () at test.f90:12
12 end function first
'''
After this change:
'''
(gdb) finish
Run till exit from #0 second (x=20, y=9) at test.f90:4
0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
10 total = second (num1 + 4, num2 * 3) ! first-breakpt
Value returned is $1 = 180
(gdb) reverse-finish
Run back to call of #0 second (x=20, y=9) at test.f90:4
0x00000000004051de in first (num1=16, num2=3) at test.f90:10
10 total = second (num1 + 4, num2 * 3) ! first-breakpt
'''
The test gdb.fortran/func-trampoline.exp is updated for testing the finish
command. The test gdb.reverse/finish-reverse-trampoline.exp is
added for testing the reverse-finish command.
2024-03-28 Ijaz, Abdul B <abdul.b.ijaz@intel.com>
---
gdb/NEWS | 5 +-
gdb/doc/gdb.texinfo | 4 ++
gdb/infcmd.c | 12 ++++
gdb/infrun.c | 8 +++
gdb/infrun.h | 5 ++
gdb/testsuite/gdb.fortran/func-trampoline.exp | 13 ++++-
.../gdb.reverse/finish-reverse-trampoline.exp | 56 +++++++++++++++++++
7 files changed, 99 insertions(+), 4 deletions(-)
create mode 100644 gdb/testsuite/gdb.reverse/finish-reverse-trampoline.exp
diff --git a/gdb/NEWS b/gdb/NEWS
index 025f2e1a17e..b8577c58af7 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -898,8 +898,9 @@ show skip-trampoline-functions
recognize function calls that have been marked as trampolines in the debug
info. It improves stepping behavior in that it steps over the trampoline
code and hides it from the user. It improves the printing of the stack by
- hiding trampoline functions from the backtrace. Currently, only DWARF
- trampolines are supported.
+ hiding the trampoline frames from the backtrace and skips trampoline
+ functions while returning from the target function of a trampoline call.
+ Currently, only DWARF trampolines are supported.
If this is turned off, GDB gdb will handle trampoline functions the same
as any other function.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 6117f6e889f..5782e06b91d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -6475,6 +6475,10 @@ DWARF trampolines marked via DW_AT_trampoline are supported by this.
When issuing a @code{backtrace}, if @code{skip-trampoline-functions} is set,
@value{GDBN} will skip trampoline frames while printing the stack.
+When issuing a @code{finish} or @code{reverse-finish}, if
+@code{skip-trampoline-functions} is set, @value{GDBN} will skip trampoline
+frames while returning from the target function.
+
Currently, only DWARF trampolines marked via DW_AT_trampoline are supported by
this.
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 600c90c055a..cd9baa03ecd 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1801,6 +1801,18 @@ finish_command (const char *arg, int from_tty)
if (frame == 0)
error (_("\"finish\" not meaningful in the outermost frame."));
+ if (skip_trampoline_functions)
+ {
+ for (int i = 0; (SAFE_TRAMPOLINE_CHAIN (i, frame)
+ && in_trampoline_frame (frame)); ++i)
+ frame = get_prev_frame (frame);
+
+ if (frame == nullptr)
+ error (_("\"finish\" not meaningful in the outermost non-trampoline \
+frame. Consider running \"set skip-trampoline-functions off\", to stop in \
+trampoline frames for the \"finish\" command."));
+ }
+
clear_proceed_status (0);
tp = inferior_thread ();
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 1c5711b8c41..5419d58bf3b 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -8095,6 +8095,14 @@ process_event_stop_test (struct execution_control_state *ecs)
keep_going (ecs);
return;
}
+ else if (skip_trampoline_functions && in_trampoline_function (stop_pc))
+ {
+ /* While reverse stepping if we are in a trampoline function call
+ we will just continue single step in the hope of leaving the
+ trampoline again soon. */
+ keep_going (ecs);
+ return;
+ }
}
/* This always returns the sal for the inner-most frame when we are in a
diff --git a/gdb/infrun.h b/gdb/infrun.h
index fbe88ad4595..3873cca7619 100644
--- a/gdb/infrun.h
+++ b/gdb/infrun.h
@@ -81,6 +81,11 @@ infrun_debug_show_threads (const char *title, ThreadRange threads)
information. */
#define MAX_TRAMPOLINE_CHAIN_SIZE 10
+/* True if the trampoline index "i" is less then the maximum allowed size
+ of a trampoline chain. */
+#define SAFE_TRAMPOLINE_CHAIN(i, frame) \
+ (i < MAX_TRAMPOLINE_CHAIN_SIZE && (frame != nullptr))
+
/* Nonzero if we want to give control to the user when we're notified
of shared library events by the dynamic linker. */
extern int stop_on_solib_events;
diff --git a/gdb/testsuite/gdb.fortran/func-trampoline.exp b/gdb/testsuite/gdb.fortran/func-trampoline.exp
index bfa0002cf0e..4cb9e4f4919 100644
--- a/gdb/testsuite/gdb.fortran/func-trampoline.exp
+++ b/gdb/testsuite/gdb.fortran/func-trampoline.exp
@@ -13,8 +13,8 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/> .
-# Test "backtrace" and "backtrace -n" commands for functions with trampoline
-# calls.
+# Test "backtrace", "backtrace -n" and "finish" commands for functions with
+# trampoline calls.
require allow_fortran_tests
@@ -75,3 +75,12 @@ with_test_prefix "backtrace outerframes" {
"#$decimal.* $middle_desc" \
"#$decimal.* $outer_desc.*"]
}
+
+with_test_prefix "finish" {
+ init_test
+
+ gdb_test "finish" [multi_line \
+ "Run till exit from #0 $fill second \\(x=20, y=9\\) $fill" \
+ "${fill}first \\(num1=16, num2=3\\)${fill}" \
+ "${fill}(\r\nValue returned is $valnum_re = 180)"]
+}
diff --git a/gdb/testsuite/gdb.reverse/finish-reverse-trampoline.exp b/gdb/testsuite/gdb.reverse/finish-reverse-trampoline.exp
new file mode 100644
index 00000000000..3a23a30ad0d
--- /dev/null
+++ b/gdb/testsuite/gdb.reverse/finish-reverse-trampoline.exp
@@ -0,0 +1,56 @@
+# Copyright 2024 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# Test "reverse-finish" command for functions with trampoline.
+
+require supports_reverse allow_fortran_tests
+
+if {![test_compiler_info {ifx-*} f90]} {
+ untested "This test is only applicable for IFX, which emits the\
+ trampoline DIE in Dwarf."
+ return -1
+}
+
+load_lib fortran.exp
+
+set testfile finish-reverse-trampoline
+set srcfile "${srcdir}/gdb.fortran/func-trampoline.f90"
+set binfile [standard_output_file $testfile]
+
+if {[prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
+ {debug f90}]} {
+ return -1
+}
+
+if {![fortran_runto_main]} {
+ return -1
+}
+
+set inner_loc [gdb_get_line_number "second-breakpt"]
+
+if [supports_process_record] {
+ # Activate process record/replay
+ gdb_test_no_output "record" "turn on process record"
+}
+
+# Set breakpoint inside the innermost function 'second'.
+gdb_breakpoint "$srcfile:$inner_loc"
+gdb_continue_to_breakpoint "innermost-body" ".*$srcfile:$inner_loc.*"
+
+gdb_test "reverse-finish" [multi_line \
+ "Run back to call of #0 second \\(x=20, y=9\\).*" \
+ ".*in first \\(num1=16, num2=3\\).*"]
+
+gdb_test "frame" "#0.*first.*" "Frame 0 shows first function"
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 06/10] gdb: Skip trampoline functions for the up command.
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
` (4 preceding siblings ...)
2024-03-28 12:05 ` [PATCH v6 05/10] gdb: Skip trampoline functions for the finish and reverse-finish commands Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 14:01 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 07/10] gdb: Skip trampoline functions for the return command Abdul Basit Ijaz
` (3 subsequent siblings)
9 siblings, 1 reply; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
This change skips trampoline functions when the option
'skip-trampoline-functions' is set to 'on' for the up command. Before this
change, GDB processes trampoline functions indicated by the compiler with
DIE "DW_AT_trampoline" and stops at the trampoline function for the 'up'
command. For better user experience, all such frames can be
skipped and hidden from the user.
In this example the IFX compiler emits "DW_AT_trampoline" tag for the 'first'
and 'second' trampoline functions like following:
function second (x, y) result(z)
integer, intent(in) :: x, y
integer :: z
z = x * y ! breakpt-up
end function second
function first (num1, num2) result(total)
integer, intent(in) :: num1, num2
integer :: total
total = second (num1 + 4, num2 * 3) ! first-breakpt
total = total + 30
end function first
Related Dwarf:
0x0000013f: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000404350)
DW_AT_high_pc (0x000000000040435f)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("second_.t74p.t75p")
DW_AT_name ("second_.t74p.t75p")
DW_AT_trampoline ("second_")
0x0000015a: DW_TAG_subprogram
DW_AT_low_pc (0x00000000004044a0)
DW_AT_high_pc (0x00000000004044af)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("first_.t104p.t105p")
DW_AT_name ("first_.t104p.t105p")
DW_AT_trampoline ("first_")
Before this change, the 'up' command output looks like:
'''
(gdb) up
\#1 0x0000000000405209 in second_.t74p.t75p () at test.f90:12
12 end function first
'''
After this change:
'''
(gdb) up
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
10 total = second (num1 + 4, num2 * 3) ! first-breakpt
'''
The test gdb.fortran/func-trampoline.exp is updated for testing this change.
2024-03-28 Ijaz, Abdul B <abdul.b.ijaz@intel.com>
---
gdb/doc/gdb.texinfo | 2 +-
gdb/stack.c | 7 +++++++
gdb/testsuite/gdb.fortran/func-trampoline.exp | 12 ++++++++++--
3 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 5782e06b91d..222faba5da3 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -6475,7 +6475,7 @@ DWARF trampolines marked via DW_AT_trampoline are supported by this.
When issuing a @code{backtrace}, if @code{skip-trampoline-functions} is set,
@value{GDBN} will skip trampoline frames while printing the stack.
-When issuing a @code{finish} or @code{reverse-finish}, if
+When issuing a @code{finish}, @code{reverse-finish} or @code{up}, if
@code{skip-trampoline-functions} is set, @value{GDBN} will skip trampoline
frames while returning from the target function.
diff --git a/gdb/stack.c b/gdb/stack.c
index 6a25054673f..2071d98ffe6 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -2605,6 +2605,13 @@ find_relative_frame (frame_info_ptr frame, int *level_offset_ptr)
{
frame_info_ptr prev = get_prev_frame (frame);
+ if (skip_trampoline_functions)
+ {
+ for (int i = 0; (SAFE_TRAMPOLINE_CHAIN (i, prev)
+ && in_trampoline_frame (prev)); ++i)
+ prev = get_prev_frame (prev);
+ }
+
if (!prev)
break;
(*level_offset_ptr)--;
diff --git a/gdb/testsuite/gdb.fortran/func-trampoline.exp b/gdb/testsuite/gdb.fortran/func-trampoline.exp
index 4cb9e4f4919..e7e4c8ae7b0 100644
--- a/gdb/testsuite/gdb.fortran/func-trampoline.exp
+++ b/gdb/testsuite/gdb.fortran/func-trampoline.exp
@@ -13,8 +13,8 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/> .
-# Test "backtrace", "backtrace -n" and "finish" commands for functions with
-# trampoline calls.
+# Test "backtrace", "backtrace -n", "finish" and "up" commands for
+# functions with trampoline calls.
require allow_fortran_tests
@@ -84,3 +84,11 @@ with_test_prefix "finish" {
"${fill}first \\(num1=16, num2=3\\)${fill}" \
"${fill}(\r\nValue returned is $valnum_re = 180)"]
}
+
+with_test_prefix "up" {
+ init_test
+
+ gdb_test "up" [multi_line \
+ "#$decimal.* $middle_desc" \
+ "${fill}first = second \\(num1 \\+ 4, num2 \\* 3\\).*${fill}"]
+}
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 07/10] gdb: Skip trampoline functions for the return command.
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
` (5 preceding siblings ...)
2024-03-28 12:05 ` [PATCH v6 06/10] gdb: Skip trampoline functions for the up command Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 14:01 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 08/10] gdb, mi: Skip trampoline functions for the -stack-list-frames command Abdul Basit Ijaz
` (2 subsequent siblings)
9 siblings, 1 reply; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
This change skips trampoline functions for the return command
when the option 'skip-trampoline-functions' is set to 'on'. Before this
change, GDB processes trampoline functions indicated by the compiler with
DIE "DW_AT_trampoline" for the return command and stops at the trampoline
functions. For better user experience, all such frames can
be skipped and hidden from the user.
In this example the IFX compiler emits "DW_AT_trampoline" tag for the 'first'
and 'second' trampoline functions like following:
function second (x, y) result(z)
integer, intent(in) :: x, y
integer :: z
z = x * y ! breakpt-return
end function second
function first (num1, num2) result(total)
integer, intent(in) :: num1, num2
integer :: total
total = second (num1 + 4, num2 * 3) ! first-breakpt
total = total + 30
end function first
Related Dwarf:
0x0000013f: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000404350)
DW_AT_high_pc (0x000000000040435f)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("second_.t74p.t75p")
DW_AT_name ("second_.t74p.t75p")
DW_AT_trampoline ("second_")
0x0000015a: DW_TAG_subprogram
DW_AT_low_pc (0x00000000004044a0)
DW_AT_high_pc (0x00000000004044af)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("first_.t104p.t105p")
DW_AT_name ("first_.t104p.t105p")
DW_AT_trampoline ("first_")
Before this change, the return command output looks like:
'''
(gdb) return
Make second return now? (y or n) y
\#0 0x0000000000405209 in second_.t74p.t75p () at test.f90:12
12 end function first
'''
After this change:
'''
(gdb) return
Make second return now? (y or n) y
\#0 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
10 total = second (num1 + 4, num2 * 3) ! first-breakpt
'''
The test gdb.fortran/func-trampoline.exp is updated for testing this change.
2024-03-28 Ijaz, Abdul B <abdul.b.ijaz@intel.com>
---
gdb/doc/gdb.texinfo | 6 +++---
gdb/stack.c | 11 +++++++++++
gdb/testsuite/gdb.fortran/func-trampoline.exp | 10 +++++++++-
3 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 222faba5da3..a6f74373dfe 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -6475,9 +6475,9 @@ DWARF trampolines marked via DW_AT_trampoline are supported by this.
When issuing a @code{backtrace}, if @code{skip-trampoline-functions} is set,
@value{GDBN} will skip trampoline frames while printing the stack.
-When issuing a @code{finish}, @code{reverse-finish} or @code{up}, if
-@code{skip-trampoline-functions} is set, @value{GDBN} will skip trampoline
-frames while returning from the target function.
+When issuing a @code{finish}, @code{reverse-finish}, @code{up} or
+@code{return}, if @code{skip-trampoline-functions} is set, @value{GDBN} will
+skip trampoline frames while returning from the target function.
Currently, only DWARF trampolines marked via DW_AT_trampoline are supported by
this.
diff --git a/gdb/stack.c b/gdb/stack.c
index 2071d98ffe6..85deedce682 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -2836,6 +2836,17 @@ return_command (const char *retval_exp, int from_tty)
if (get_frame_type (get_current_frame ()) == DUMMY_FRAME)
frame_pop (get_current_frame ());
+ if (skip_trampoline_functions)
+ {
+ frame_info_ptr ret_frame = get_current_frame ();
+ for (int i = 0; (SAFE_TRAMPOLINE_CHAIN (i, ret_frame)
+ && in_trampoline_frame (ret_frame)); ++i)
+ {
+ frame_pop (ret_frame);
+ ret_frame = get_current_frame ();
+ }
+ }
+
select_frame (get_current_frame ());
/* If interactive, print the frame that is now current. */
if (from_tty)
diff --git a/gdb/testsuite/gdb.fortran/func-trampoline.exp b/gdb/testsuite/gdb.fortran/func-trampoline.exp
index e7e4c8ae7b0..dd26e5ab035 100644
--- a/gdb/testsuite/gdb.fortran/func-trampoline.exp
+++ b/gdb/testsuite/gdb.fortran/func-trampoline.exp
@@ -13,7 +13,7 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/> .
-# Test "backtrace", "backtrace -n", "finish" and "up" commands for
+# Test "backtrace", "backtrace -n", "finish", "up" and "return" commands for
# functions with trampoline calls.
require allow_fortran_tests
@@ -92,3 +92,11 @@ with_test_prefix "up" {
"#$decimal.* $middle_desc" \
"${fill}first = second \\(num1 \\+ 4, num2 \\* 3\\).*${fill}"]
}
+
+with_test_prefix "return" {
+ init_test
+
+ gdb_test "return" \
+ ".*first = second \\(num1 \\+ 4, num2 \\* 3\\) \\! first-breakpt" \
+ "" "Make second return now.*y or n. $" "y"
+}
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 08/10] gdb, mi: Skip trampoline functions for the -stack-list-frames command.
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
` (6 preceding siblings ...)
2024-03-28 12:05 ` [PATCH v6 07/10] gdb: Skip trampoline functions for the return command Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 14:02 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 09/10] gdb, mi: Skip trampoline functions for the -stack-list-arguments command Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 10/10] gdb: Filter trampoline frames in backtrace when using Python frame-filters Abdul Basit Ijaz
9 siblings, 1 reply; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
This change skips trampoline functions for the '-stack-list-frames' command
when the option 'skip-trampoline-functions' is set to 'on'. Before this
change, GDB prints the frames indicated by the compiler with DIE
"DW_AT_trampoline" in the backtrace for mi command stack-list-frames, but
for better user experience, all such frames can be hidden from the user.
In this example the IFX compiler emits "DW_AT_trampoline" tag for the 'first'
and 'second' trampoline functions like following:
function second (x, y) result(z)
integer, intent(in) :: x, y
integer :: z
z = x * y ! breakpt-backtrace
end function second
function first (num1, num2) result(total)
integer, intent(in) :: num1, num2
integer :: total
total = second (num1 + 4, num2 * 3) ! first-breakpt
total = total + 30
end function first
Related Dwarf:
0x0000013f: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000404350)
DW_AT_high_pc (0x000000000040435f)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("second_.t74p.t75p")
DW_AT_name ("second_.t74p.t75p")
DW_AT_trampoline ("second_")
0x0000015a: DW_TAG_subprogram
DW_AT_low_pc (0x00000000004044a0)
DW_AT_high_pc (0x00000000004044af)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("first_.t104p.t105p")
DW_AT_name ("first_.t104p.t105p")
DW_AT_trampoline ("first_")
Before this change, the '-stack-list-frames' command output looks like:
'''
(gdb) -stack-list-frames
-stack-list-frames
^done,
stack=[
frame={level="0",addr="0x0000000000405194",func="second",
file="test.f90",fullname="/home/test.f90",line="4",
arch="i386:x86-64"},
frame={level="1",addr="0x0000000000405209",
func="second_.t74p.t75p",
file="test.f90",fullname="/home/test.f90",line="12",
arch="i386:x86-64"},
frame={level="2",addr="0x00000000004051e3",func="first",
file="test.f90",fullname="/home/test.f90",line="10",
arch="i386:x86-64"},
frame={level="3",addr="0x0000000000405309",
func="first_.t95p.t96p",file="test.f90",
fullname="/home/test.f90",line="21",arch="i386:x86-64"},
frame={level="4",addr="0x0000000000405234",
func="func_trampoline",file="test.f90",
fullname="/home/test.f90",line="17",arch="i386:x86-64"}]
'''
After this change:
'''
(gdb) -stack-list-frames
-stack-list-frames
^done,
stack=[frame={level="0",addr="0x0000000000405194",func="second",
file="test.f90",fullname="/home/test.f90",line="4",
arch="i386:x86-64"},
frame={level="2",addr="0x00000000004051e3",func="first",
file="test.f90",fullname="/home/test.f90",line="10",
arch="i386:x86-64"},
frame={level="4",addr="0x0000000000405234",
func="func_trampoline",file="test.f90",fullname="/home/test.f90",
line="17",arch="i386:x86-64"}]
'''
New test gdb.mi/mi-func-trampoline.exp is added for testing the change.
2024-03-28 Ijaz, Abdul B <abdul.b.ijaz@intel.com>
---
gdb/doc/gdb.texinfo | 4 +-
gdb/mi/mi-cmd-stack.c | 7 +++
gdb/testsuite/gdb.mi/mi-func-trampoline.exp | 68 +++++++++++++++++++++
3 files changed, 78 insertions(+), 1 deletion(-)
create mode 100644 gdb/testsuite/gdb.mi/mi-func-trampoline.exp
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a6f74373dfe..90221e9b9c1 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -34866,7 +34866,9 @@ an error if @var{low-frame} is larger than the actual number of
frames. On the other hand, @var{high-frame} may be larger than the
actual number of frames, in which case only existing frames will be
returned. If the option @code{--no-frame-filters} is supplied, then
-Python frame filters will not be executed.
+Python frame filters will not be executed. If the option
+@code{skip-trampoline-functions} is set, @value{GDBN} will skip the trampoline
+frames while printing a backtrace.
@subsubheading @value{GDBN} Command
diff --git a/gdb/mi/mi-cmd-stack.c b/gdb/mi/mi-cmd-stack.c
index b78c169e70b..830edcb816e 100644
--- a/gdb/mi/mi-cmd-stack.c
+++ b/gdb/mi/mi-cmd-stack.c
@@ -177,6 +177,13 @@ mi_cmd_stack_list_frames (const char *command, const char *const *argv,
i++, fi = get_prev_frame (fi))
{
QUIT;
+ if (skip_trampoline_functions)
+ {
+ for (int j = 0; (SAFE_TRAMPOLINE_CHAIN (j, fi)
+ && in_trampoline_frame (fi)); ++j)
+ fi = get_prev_frame (fi);
+ }
+
/* Print the location and the address always, even for level 0.
If args is 0, don't print the arguments. */
print_frame_info (user_frame_print_options,
diff --git a/gdb/testsuite/gdb.mi/mi-func-trampoline.exp b/gdb/testsuite/gdb.mi/mi-func-trampoline.exp
new file mode 100644
index 00000000000..34a2c464f21
--- /dev/null
+++ b/gdb/testsuite/gdb.mi/mi-func-trampoline.exp
@@ -0,0 +1,68 @@
+# Copyright 2024 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/> .
+
+# Test -stack-list-frames command for functions with trampoline
+# calls. Also checks if trampoline frames are filtered while printing
+# stack.
+
+require allow_fortran_tests
+
+if {![test_compiler_info {ifx-*} f90]} {
+ untested "This test is only applicable for IFX, which emits the\
+ trampoline DIE in Dwarf."
+ return -1
+}
+
+load_lib fortran.exp
+load_lib mi-support.exp
+
+set MIFLAGS "-i=mi"
+
+if {[mi_clean_restart]} {
+ return
+}
+
+set testfile mi-func-trampoline
+set srcfile "${srcdir}/gdb.fortran/func-trampoline.f90"
+set binfile [standard_output_file $testfile]
+
+if { [gdb_compile "${srcfile}" "${binfile}" executable \
+ {debug f90} ] != "" } {
+ untested "failed to compile"
+ return -1
+}
+
+mi_delete_breakpoints
+mi_gdb_reinitialize_dir $srcdir/$subdir
+mi_gdb_load ${binfile}
+
+set inner_loc [gdb_get_line_number "second-breakpt"]
+set fill "\[^\r\n\]*"
+
+set frame1_regx "\{level=\"0\",addr=\"$hex\",func=\"second\",file=\".*func-trampoline.f90\",fullname=\"${fullname_syntax}func-trampoline.f90\",line=\"$inner_loc\",arch=\".*\"\}"
+set frame2_regx "\{level=\"2\",addr=\"$hex\",func=\"first\",.*\}"
+set frame3_regx "\{level=\"4\",addr=\"$hex\",func=\"func_trampoline\",.*\}"
+
+# Set breakpoint inside the innermost function 'second'.
+mi_create_breakpoint "-t $srcfile:$inner_loc" \
+ "insert breakpoint at line $inner_loc " \
+ -number 1 -disp del -func second ".*trampoline.f90" $inner_loc $hex
+mi_run_cmd
+mi_expect_stop \
+ "breakpoint-hit" "second" ".*" ".*trampoline.f90" "\[0-9\]+" { "" "disp=\"del\"" } \
+ "run to breakpoint at line $inner_loc"
+
+mi_gdb_test "100-stack-list-frames" \
+ "100\\^done,stack=\\\[frame=${frame1_regx},frame=${frame2_regx},frame=${frame3_regx}\\\]"
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 09/10] gdb, mi: Skip trampoline functions for the -stack-list-arguments command.
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
` (7 preceding siblings ...)
2024-03-28 12:05 ` [PATCH v6 08/10] gdb, mi: Skip trampoline functions for the -stack-list-frames command Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
2024-03-28 14:03 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 10/10] gdb: Filter trampoline frames in backtrace when using Python frame-filters Abdul Basit Ijaz
9 siblings, 1 reply; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
This change skips trampoline functions for the '-stack-list-arguments'
command when the option 'skip-trampoline-functions' is set to 'on'. Before
this change, GDB prints the arguments of frames indicated by the
compiler with DIE "DW_AT_trampoline" in the backtrace for the mi command
stack-list-arguments, but for better user experience, all such frames
can be hidden from the user.
In this example the IFX compiler emits "DW_AT_trampoline" tag for the
'first' and 'second' trampoline functions like following:
function second (x, y) result(z)
integer, intent(in) :: x, y
integer :: z
z = x * y ! breakpt-args
end function second
function first (num1, num2) result(total)
integer, intent(in) :: num1, num2
integer :: total
total = second (num1 + 4, num2 * 3) ! first-breakpt
total = total + 30
end function first
Related Dwarf:
0x0000013f: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000404350)
DW_AT_high_pc (0x000000000040435f)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("second_.t74p.t75p")
DW_AT_name ("second_.t74p.t75p")
DW_AT_trampoline ("second_")
0x0000015a: DW_TAG_subprogram
DW_AT_low_pc (0x00000000004044a0)
DW_AT_high_pc (0x00000000004044af)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("first_.t104p.t105p")
DW_AT_name ("first_.t104p.t105p")
DW_AT_trampoline ("first_")
Before this change, the -stack-list-arguments' command output looks like:
'''
(gdb)
-stack-list-arguments 0
^done,
stack-args=[
frame={level="0",args=[name="x",name="y"]},
frame={level="1",args=[]},
frame={level="2",args=[name="num1",name="num2"]},
frame={level="3",args=[]},
frame={level="4",args=[]}]
'''
After change:
'''
(gdb)
-stack-list-arguments 0
^done,
stack-args=[
frame={level="0",args=[name="x",name="y"]},
frame={level="1",args=[name="num1",name="num2"]},
frame={level="2",args=[]}]
'''
The test gdb.mi/mi-func-treampoline is updated for testing the change.
2024-03-28 Ijaz, Abdul B <abdul.b.ijaz@intel.com>
---
gdb/doc/gdb.texinfo | 4 ++++
gdb/mi/mi-cmd-stack.c | 7 +++++++
gdb/testsuite/gdb.mi/mi-func-trampoline.exp | 13 ++++++++++---
3 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 90221e9b9c1..6b2f40c906c 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -35183,6 +35183,10 @@ variable object is updated, @value{GDBN} makes sure that the
thread/frame combination the variable object is bound to still exists,
and re-evaluates the variable object in context of that thread/frame.
+If the option @code{skip-trampoline-functions} is set for the
+@code{-stack-list-arguments}, @value{GDBN} will not show trampoline
+functions in the stack.
+
The following is the complete set of @sc{gdb/mi} operations defined to
access this functionality:
diff --git a/gdb/mi/mi-cmd-stack.c b/gdb/mi/mi-cmd-stack.c
index 830edcb816e..9b288c3fe03 100644
--- a/gdb/mi/mi-cmd-stack.c
+++ b/gdb/mi/mi-cmd-stack.c
@@ -404,6 +404,13 @@ mi_cmd_stack_list_args (const char *command, const char *const *argv, int argc)
i++, fi = get_prev_frame (fi))
{
QUIT;
+ if (skip_trampoline_functions)
+ {
+ for (int j = 0; (SAFE_TRAMPOLINE_CHAIN (j, fi)
+ && in_trampoline_frame (fi)); ++j)
+ fi = get_prev_frame (fi);
+ }
+
ui_out_emit_tuple tuple_emitter (uiout, "frame");
uiout->field_signed ("level", i);
list_args_or_locals (user_frame_print_options,
diff --git a/gdb/testsuite/gdb.mi/mi-func-trampoline.exp b/gdb/testsuite/gdb.mi/mi-func-trampoline.exp
index 34a2c464f21..44daba74cde 100644
--- a/gdb/testsuite/gdb.mi/mi-func-trampoline.exp
+++ b/gdb/testsuite/gdb.mi/mi-func-trampoline.exp
@@ -13,9 +13,9 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/> .
-# Test -stack-list-frames command for functions with trampoline
-# calls. Also checks if trampoline frames are filtered while printing
-# stack.
+# Test -stack-list-frames and -stack-list-arguments command for functions
+# with trampoline calls. Also checks if trampoline frames are filtered
+# while printing stack.
require allow_fortran_tests
@@ -55,6 +55,10 @@ set frame1_regx "\{level=\"0\",addr=\"$hex\",func=\"second\",file=\".*func-tramp
set frame2_regx "\{level=\"2\",addr=\"$hex\",func=\"first\",.*\}"
set frame3_regx "\{level=\"4\",addr=\"$hex\",func=\"func_trampoline\",.*\}"
+set arg1_regx "\{level=\"0\",args=\\\[name=\"x\",name=\"y\"\\\]\}"
+set arg2_regx "\{level=\"1\",args=\\\[name=\"num1\",name=\"num2\"\\\]\}"
+set arg3_regx "\{level=\"2\",args=\\\[\\\]\}"
+
# Set breakpoint inside the innermost function 'second'.
mi_create_breakpoint "-t $srcfile:$inner_loc" \
"insert breakpoint at line $inner_loc " \
@@ -66,3 +70,6 @@ mi_expect_stop \
mi_gdb_test "100-stack-list-frames" \
"100\\^done,stack=\\\[frame=${frame1_regx},frame=${frame2_regx},frame=${frame3_regx}\\\]"
+
+mi_gdb_test "200-stack-list-arguments 0" \
+ "200\\^done,stack-args=\\\[frame=${arg1_regx},frame=${arg2_regx},frame=${arg3_regx}\\\]"
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH v6 10/10] gdb: Filter trampoline frames in backtrace when using Python frame-filters.
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
` (8 preceding siblings ...)
2024-03-28 12:05 ` [PATCH v6 09/10] gdb, mi: Skip trampoline functions for the -stack-list-arguments command Abdul Basit Ijaz
@ 2024-03-28 12:05 ` Abdul Basit Ijaz
9 siblings, 0 replies; 18+ messages in thread
From: Abdul Basit Ijaz @ 2024-03-28 12:05 UTC (permalink / raw)
To: gdb-patches; +Cc: abdul.b.ijaz, JiniSusan.George, tom, eliz
From: "Ijaz, Abdul B" <abdul.b.ijaz@intel.com>
In case of the Python frame-filters, this change filters trampoline functions
when the option 'skip-trampoline-functions' is set to 'on'. GDB recently
added the option to hide frames that are marked by the compiler with
"DW_AT_trampoline", see commit 'Skip trampoline frames for the backtrace
command'. This implements the same functionality when python frame filters
are in use.
In this example the IFX compiler emits "DW_AT_trampoline" tag for the 'first'
and 'second' trampoline functions like following:
function second (x, y) result(z)
integer, intent(in) :: x, y
integer :: z
z = x * y ! breakpt-framefilter
end function second
function first (num1, num2) result(total)
integer, intent(in) :: num1, num2
integer :: total
total = second (num1 + 4, num2 * 3) ! first-breakpt
total = total + 30
end function first
Related Dwarf:
0x0000013f: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000404350)
DW_AT_high_pc (0x000000000040435f)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("second_.t74p.t75p")
DW_AT_name ("second_.t74p.t75p")
DW_AT_trampoline ("second_")
0x0000015a: DW_TAG_subprogram
DW_AT_low_pc (0x00000000004044a0)
DW_AT_high_pc (0x00000000004044af)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_linkage_name ("first_.t104p.t105p")
DW_AT_name ("first_.t104p.t105p")
DW_AT_trampoline ("first_")
Once frame filters are enabled the backtrace command output before this
change looks like:
'''
(gdb) info frame-filter
global frame-filters:
Priority Enabled Name
100 Yes TestTrampolineFrameFilter
(gdb) backtrace 3
\#0 second (x=20, y=9) at test.f90:4
\#1 0x0000000000405209 in second_.t74p.t75p () at test.f90:12
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
(gdb) backtrace -3
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
\#3 0x0000000000405309 in first_.t95p.t96p () at test.f90:21
\#4 0x0000000000405234 in func_trampoline () at test.f90:17
'''
After this change:
'''
(gdb) info frame-filter
global frame-filters:
Priority Enabled Name
100 Yes TestTrampolineFrameFilter
(gdb) backtrace 3
\#0 second (x=20, y=9) at test.f90:4
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
\#4 0x0000000000405234 in func_trampoline () at test.f90:17
(gdb) backtrace -3
\#2 0x00000000004051e3 in first (num1=16, num2=3) at test.f90:10
\#4 0x0000000000405234 in func_trampoline () at test.f90:17
'''
New test gdb.python/py-framefilter-trampoline.exp is added to test this change.
2024-03-28 Ijaz, Abdul B <abdul.b.ijaz@intel.com>
---
gdb/python/py-frame.c | 11 +++
.../gdb.python/py-framefilter-trampoline.exp | 77 +++++++++++++++++++
.../gdb.python/py-framefilter-trampoline.py | 31 ++++++++
3 files changed, 119 insertions(+)
create mode 100644 gdb/testsuite/gdb.python/py-framefilter-trampoline.exp
create mode 100644 gdb/testsuite/gdb.python/py-framefilter-trampoline.py
diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c
index bbb42afb2ed..5c07ba58b23 100644
--- a/gdb/python/py-frame.c
+++ b/gdb/python/py-frame.c
@@ -70,6 +70,17 @@ frame_object_to_frame_info (PyObject *obj)
if (frame_obj->frame_id_is_next)
frame = get_prev_frame (frame);
+ if (skip_trampoline_functions)
+ {
+ for (int i = 0; (SAFE_TRAMPOLINE_CHAIN (i, frame)
+ && in_trampoline_frame (frame)); ++i)
+ {
+ frame = get_prev_frame (frame);
+ if (frame == nullptr)
+ return nullptr;
+ }
+ }
+
return frame;
}
diff --git a/gdb/testsuite/gdb.python/py-framefilter-trampoline.exp b/gdb/testsuite/gdb.python/py-framefilter-trampoline.exp
new file mode 100644
index 00000000000..76dbdaa970a
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-framefilter-trampoline.exp
@@ -0,0 +1,77 @@
+# Copyright (C) 2024 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the GDB testsuite. It tests skipping of trampolines
+# in the backtrace command in case Python-based frame-filters are enabled.
+
+load_lib gdb-python.exp
+
+require allow_python_tests allow_fortran_tests
+
+if {![test_compiler_info {ifx-*} f90]} {
+ untested "This test is only applicable for IFX, which emits the\
+ trampoline DIE in Dwarf."
+ return -1
+}
+
+load_lib fortran.exp
+
+set testfile py-framefilter-trampoline
+set srcfile "${srcdir}/gdb.fortran/func-trampoline.f90"
+set binfile [standard_output_file $testfile]
+
+if {[build_executable $testfile.exp $testfile $srcfile {debug f90}] == -1} {
+ return -1
+}
+
+# Start with a fresh gdb.
+gdb_exit
+gdb_start
+
+gdb_test "info frame-filter" \
+ "No frame filters\\." \
+ "info frame filter before loading filters"
+
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+if {![runto_main]} {
+ return
+}
+gdb_test_no_output "set python print-stack full" \
+ "set python print-stack to full"
+
+# Load frame-filters
+set remote_python_file [gdb_remote_download host \
+ ${srcdir}/${subdir}/${testfile}.py]
+gdb_test_no_output "source ${remote_python_file}" "load python file"
+
+set inner_loc [gdb_get_line_number "second-breakpt"]
+set middle_loc [gdb_get_line_number "first-breakpt"]
+set outer_loc [gdb_get_line_number "main-outer-loc"]
+set fill "\[^\r\n\]*"
+
+set inner_desc "second \\(x=20, y=9\\) at ${fill}$srcfile:$inner_loc"
+set middle_desc "first \\(num1=16, num2=3\\) at ${fill}$srcfile:$middle_loc"
+set outer_desc ".* at .*$srcfile:$outer_loc"
+
+# Set breakpoint inside the innermost function 'second'.
+gdb_breakpoint "$srcfile:$inner_loc"
+gdb_continue_to_breakpoint "innermost-body" ".*$srcfile:$inner_loc.*"
+
+# Test with frame filter.
+gdb_test "bt" [multi_line \
+ "#$decimal.* $middle_desc" \
+ "#$decimal.* $outer_desc.*"]
diff --git a/gdb/testsuite/gdb.python/py-framefilter-trampoline.py b/gdb/testsuite/gdb.python/py-framefilter-trampoline.py
new file mode 100644
index 00000000000..0e9dfd7af2a
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-framefilter-trampoline.py
@@ -0,0 +1,31 @@
+# Copyright (C) 2024 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the GDB testsuite. It tests if trampolines are
+# skipped when Python-based frame-filters are enabled.
+
+import gdb
+
+class TestTrampolineFrameFilter():
+ def __init__(self):
+ self.name = "TestTrampolineFrameFilter"
+ self.priority = 100
+ self.enabled = True
+ gdb.frame_filters[self.name] = self
+
+ def filter(self, frame_iter):
+ return frame_iter
+
+TestTrampolineFrameFilter()
--
2.34.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline
2024-03-28 12:05 ` [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline Abdul Basit Ijaz
@ 2024-03-28 13:58 ` Eli Zaretskii
2024-03-28 14:31 ` Ijaz, Abdul B
0 siblings, 1 reply; 18+ messages in thread
From: Eli Zaretskii @ 2024-03-28 13:58 UTC (permalink / raw)
To: Abdul Basit Ijaz
Cc: gdb-patches, JiniSusan.George, tom, nils-christian.kempke
> From: Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
> Cc: abdul.b.ijaz@intel.com,
> JiniSusan.George@amd.com,
> tom@tromey.com,
> eliz@gnu.org,
> Nils-Christian Kempke <nils-christian.kempke@intel.com>
> Date: Thu, 28 Mar 2024 13:05:21 +0100
>
> gdb/NEWS | 11 +
> gdb/doc/gdb.texinfo | 35 +++
> gdb/infrun.c | 87 ++++++-
> gdb/infrun.h | 5 +
> .../gdb.dwarf2/dw2-function-trampolines.c | 80 ++++++
> .../gdb.dwarf2/dw2-function-trampolines.exp | 245 ++++++++++++++++++
> 6 files changed, 459 insertions(+), 4 deletions(-)
> create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.c
> create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.exp
Thanks.
> diff --git a/gdb/NEWS b/gdb/NEWS
> index feb3a37393a..da0d936ff70 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -892,6 +892,17 @@ platform.
>
> * New commands
>
> +set skip-trampoline-functions on|off
> +show skip-trampoline-functions
> + This setting is 'on' by default. When 'on' it controls whether GDB will
> + recognize function calls that have been marked as trampolines in the debug
> + info. It improves stepping behavior in that it steps over the trampoline
> + code and hides it from the user. Currently, only DWARF trampolines are
> + supported.
> +
> + If this is turned off, GDB gdb will handle trampoline functions the same
^^^^^^^
Redundant "gdb" there.
> +@kindex set skip-trampoline-functions
> +@item set skip-trampoline-functions
> +@cindex trampoline functions
> +@cindex stepping through trampoline functions
> +@itemx set skip-trampoline-functions on
> +When calling a function in any language, some compilers might generate
> +so-called trampoline functions, which wrap the actual function call (the
"trampoline functions" should be in @dfn, as you are introducing new
terminology here.
> + add_setshow_boolean_cmd ("skip-trampoline-functions", class_run,
> + &skip_trampoline_functions, _("\
> +Set whether gdb attempts to hide trampolines marked in the debug info."), _("\
> +Show whether gdb attempts to hide trampolines marked in the debug info."), _("\
> +If on, while stepping gdb will skip through functions and inlined functions\n\
> +marked as trampolines by the compiler. If off, gdb will ignore such function\n\
> +trampolines."),
In the last sentence, I think "ignore such function trampolines" is
misleading. I suggest to replace this with "treat trampolines as
normal functions".
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v6 05/10] gdb: Skip trampoline functions for the finish and reverse-finish commands.
2024-03-28 12:05 ` [PATCH v6 05/10] gdb: Skip trampoline functions for the finish and reverse-finish commands Abdul Basit Ijaz
@ 2024-03-28 13:59 ` Eli Zaretskii
0 siblings, 0 replies; 18+ messages in thread
From: Eli Zaretskii @ 2024-03-28 13:59 UTC (permalink / raw)
To: Abdul Basit Ijaz; +Cc: gdb-patches, JiniSusan.George, tom
> From: Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
> Cc: abdul.b.ijaz@intel.com,
> JiniSusan.George@amd.com,
> tom@tromey.com,
> eliz@gnu.org
> Date: Thu, 28 Mar 2024 13:05:23 +0100
>
> gdb/NEWS | 5 +-
> gdb/doc/gdb.texinfo | 4 ++
> gdb/infcmd.c | 12 ++++
> gdb/infrun.c | 8 +++
> gdb/infrun.h | 5 ++
> gdb/testsuite/gdb.fortran/func-trampoline.exp | 13 ++++-
> .../gdb.reverse/finish-reverse-trampoline.exp | 56 +++++++++++++++++++
> 7 files changed, 99 insertions(+), 4 deletions(-)
> create mode 100644 gdb/testsuite/gdb.reverse/finish-reverse-trampoline.exp
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index 025f2e1a17e..b8577c58af7 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -898,8 +898,9 @@ show skip-trampoline-functions
> recognize function calls that have been marked as trampolines in the debug
> info. It improves stepping behavior in that it steps over the trampoline
> code and hides it from the user. It improves the printing of the stack by
> - hiding trampoline functions from the backtrace. Currently, only DWARF
> - trampolines are supported.
> + hiding the trampoline frames from the backtrace and skips trampoline
> + functions while returning from the target function of a trampoline call.
> + Currently, only DWARF trampolines are supported.
>
> If this is turned off, GDB gdb will handle trampoline functions the same
> as any other function.
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 6117f6e889f..5782e06b91d 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -6475,6 +6475,10 @@ DWARF trampolines marked via DW_AT_trampoline are supported by this.
> When issuing a @code{backtrace}, if @code{skip-trampoline-functions} is set,
> @value{GDBN} will skip trampoline frames while printing the stack.
>
> +When issuing a @code{finish} or @code{reverse-finish}, if
> +@code{skip-trampoline-functions} is set, @value{GDBN} will skip trampoline
> +frames while returning from the target function.
> +
> Currently, only DWARF trampolines marked via DW_AT_trampoline are supported by
> this.
Thanks, the documentation parts of this are okay.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v6 06/10] gdb: Skip trampoline functions for the up command.
2024-03-28 12:05 ` [PATCH v6 06/10] gdb: Skip trampoline functions for the up command Abdul Basit Ijaz
@ 2024-03-28 14:01 ` Eli Zaretskii
0 siblings, 0 replies; 18+ messages in thread
From: Eli Zaretskii @ 2024-03-28 14:01 UTC (permalink / raw)
To: Abdul Basit Ijaz; +Cc: gdb-patches, JiniSusan.George, tom
> From: Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
> Cc: abdul.b.ijaz@intel.com,
> JiniSusan.George@amd.com,
> tom@tromey.com,
> eliz@gnu.org
> Date: Thu, 28 Mar 2024 13:05:24 +0100
>
> gdb/doc/gdb.texinfo | 2 +-
> gdb/stack.c | 7 +++++++
> gdb/testsuite/gdb.fortran/func-trampoline.exp | 12 ++++++++++--
> 3 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 5782e06b91d..222faba5da3 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -6475,7 +6475,7 @@ DWARF trampolines marked via DW_AT_trampoline are supported by this.
> When issuing a @code{backtrace}, if @code{skip-trampoline-functions} is set,
> @value{GDBN} will skip trampoline frames while printing the stack.
>
> -When issuing a @code{finish} or @code{reverse-finish}, if
> +When issuing a @code{finish}, @code{reverse-finish} or @code{up}, if
> @code{skip-trampoline-functions} is set, @value{GDBN} will skip trampoline
> frames while returning from the target function.
The gdb.texinfo part is okay, thanks.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v6 07/10] gdb: Skip trampoline functions for the return command.
2024-03-28 12:05 ` [PATCH v6 07/10] gdb: Skip trampoline functions for the return command Abdul Basit Ijaz
@ 2024-03-28 14:01 ` Eli Zaretskii
0 siblings, 0 replies; 18+ messages in thread
From: Eli Zaretskii @ 2024-03-28 14:01 UTC (permalink / raw)
To: Abdul Basit Ijaz; +Cc: gdb-patches, JiniSusan.George, tom
> From: Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
> Cc: abdul.b.ijaz@intel.com,
> JiniSusan.George@amd.com,
> tom@tromey.com,
> eliz@gnu.org
> Date: Thu, 28 Mar 2024 13:05:25 +0100
>
> gdb/doc/gdb.texinfo | 6 +++---
> gdb/stack.c | 11 +++++++++++
> gdb/testsuite/gdb.fortran/func-trampoline.exp | 10 +++++++++-
> 3 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 222faba5da3..a6f74373dfe 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -6475,9 +6475,9 @@ DWARF trampolines marked via DW_AT_trampoline are supported by this.
> When issuing a @code{backtrace}, if @code{skip-trampoline-functions} is set,
> @value{GDBN} will skip trampoline frames while printing the stack.
>
> -When issuing a @code{finish}, @code{reverse-finish} or @code{up}, if
> -@code{skip-trampoline-functions} is set, @value{GDBN} will skip trampoline
> -frames while returning from the target function.
> +When issuing a @code{finish}, @code{reverse-finish}, @code{up} or
> +@code{return}, if @code{skip-trampoline-functions} is set, @value{GDBN} will
> +skip trampoline frames while returning from the target function.
>
> Currently, only DWARF trampolines marked via DW_AT_trampoline are supported by
> this.
The gdb.texinfo part is okay, thanks.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v6 08/10] gdb, mi: Skip trampoline functions for the -stack-list-frames command.
2024-03-28 12:05 ` [PATCH v6 08/10] gdb, mi: Skip trampoline functions for the -stack-list-frames command Abdul Basit Ijaz
@ 2024-03-28 14:02 ` Eli Zaretskii
0 siblings, 0 replies; 18+ messages in thread
From: Eli Zaretskii @ 2024-03-28 14:02 UTC (permalink / raw)
To: Abdul Basit Ijaz; +Cc: gdb-patches, JiniSusan.George, tom
> From: Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
> Cc: abdul.b.ijaz@intel.com,
> JiniSusan.George@amd.com,
> tom@tromey.com,
> eliz@gnu.org
> Date: Thu, 28 Mar 2024 13:05:26 +0100
>
> gdb/doc/gdb.texinfo | 4 +-
> gdb/mi/mi-cmd-stack.c | 7 +++
> gdb/testsuite/gdb.mi/mi-func-trampoline.exp | 68 +++++++++++++++++++++
> 3 files changed, 78 insertions(+), 1 deletion(-)
> create mode 100644 gdb/testsuite/gdb.mi/mi-func-trampoline.exp
>
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index a6f74373dfe..90221e9b9c1 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -34866,7 +34866,9 @@ an error if @var{low-frame} is larger than the actual number of
> frames. On the other hand, @var{high-frame} may be larger than the
> actual number of frames, in which case only existing frames will be
> returned. If the option @code{--no-frame-filters} is supplied, then
> -Python frame filters will not be executed.
> +Python frame filters will not be executed. If the option
> +@code{skip-trampoline-functions} is set, @value{GDBN} will skip the trampoline
> +frames while printing a backtrace.
>
> @subsubheading @value{GDBN} Command
OK for the gdb.texinfo part, thanks.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH v6 09/10] gdb, mi: Skip trampoline functions for the -stack-list-arguments command.
2024-03-28 12:05 ` [PATCH v6 09/10] gdb, mi: Skip trampoline functions for the -stack-list-arguments command Abdul Basit Ijaz
@ 2024-03-28 14:03 ` Eli Zaretskii
0 siblings, 0 replies; 18+ messages in thread
From: Eli Zaretskii @ 2024-03-28 14:03 UTC (permalink / raw)
To: Abdul Basit Ijaz; +Cc: gdb-patches, JiniSusan.George, tom
> From: Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
> Cc: abdul.b.ijaz@intel.com,
> JiniSusan.George@amd.com,
> tom@tromey.com,
> eliz@gnu.org
> Date: Thu, 28 Mar 2024 13:05:27 +0100
>
> gdb/doc/gdb.texinfo | 4 ++++
> gdb/mi/mi-cmd-stack.c | 7 +++++++
> gdb/testsuite/gdb.mi/mi-func-trampoline.exp | 13 ++++++++++---
> 3 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 90221e9b9c1..6b2f40c906c 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -35183,6 +35183,10 @@ variable object is updated, @value{GDBN} makes sure that the
> thread/frame combination the variable object is bound to still exists,
> and re-evaluates the variable object in context of that thread/frame.
>
> +If the option @code{skip-trampoline-functions} is set for the
> +@code{-stack-list-arguments}, @value{GDBN} will not show trampoline
> +functions in the stack.
> +
> The following is the complete set of @sc{gdb/mi} operations defined to
> access this functionality:
The documentation part is approved, thanks.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
^ permalink raw reply [flat|nested] 18+ messages in thread
* RE: [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline
2024-03-28 13:58 ` Eli Zaretskii
@ 2024-03-28 14:31 ` Ijaz, Abdul B
0 siblings, 0 replies; 18+ messages in thread
From: Ijaz, Abdul B @ 2024-03-28 14:31 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: gdb-patches, JiniSusan.George, tom
Thanks a lot Eli for the feedback. Will wait for the overall feedback and then will fix the issues you mentioned in next series for this patch.
>> + If this is turned off, GDB gdb will handle trampoline functions the
>> + same
^^^^^^^
>Redundant "gdb" there.
Will remove "gdb".
>> +some compilers might generate so-called trampoline functions, which
>> +wrap the actual function call (the
>"trampoline functions" should be in @dfn, as you are introducing new terminology here.
Wil add @dfn for "trampoline functions".
>> +ignore such function\n\ trampolines."),
>In the last sentence, I think "ignore such function trampolines" is misleading. I suggest to replace this with "treat trampolines as normal functions".
Will update accordingly.
Thanks & Best Regards
Abdul Basit
-----Original Message-----
From: Eli Zaretskii <eliz@gnu.org>
Sent: Thursday, March 28, 2024 2:59 PM
To: Ijaz, Abdul B <abdul.b.ijaz@intel.com>
Cc: gdb-patches@sourceware.org; JiniSusan.George@amd.com; tom@tromey.com; nils-christian.kempke@intel.com
Subject: Re: [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline
> From: Abdul Basit Ijaz <abdul.b.ijaz@intel.com>
> Cc: abdul.b.ijaz@intel.com,
> JiniSusan.George@amd.com,
> tom@tromey.com,
> eliz@gnu.org,
> Nils-Christian Kempke <nils-christian.kempke@intel.com>
> Date: Thu, 28 Mar 2024 13:05:21 +0100
>
> gdb/NEWS | 11 +
> gdb/doc/gdb.texinfo | 35 +++
> gdb/infrun.c | 87 ++++++-
> gdb/infrun.h | 5 +
> .../gdb.dwarf2/dw2-function-trampolines.c | 80 ++++++
> .../gdb.dwarf2/dw2-function-trampolines.exp | 245 ++++++++++++++++++
> 6 files changed, 459 insertions(+), 4 deletions(-) create mode
> 100644 gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.c
> create mode 100644
> gdb/testsuite/gdb.dwarf2/dw2-function-trampolines.exp
Thanks.
> diff --git a/gdb/NEWS b/gdb/NEWS
> index feb3a37393a..da0d936ff70 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -892,6 +892,17 @@ platform.
>
> * New commands
>
> +set skip-trampoline-functions on|off
> +show skip-trampoline-functions
> + This setting is 'on' by default. When 'on' it controls whether GDB
> +will
> + recognize function calls that have been marked as trampolines in
> +the debug
> + info. It improves stepping behavior in that it steps over the
> +trampoline
> + code and hides it from the user. Currently, only DWARF trampolines
> +are
> + supported.
> +
> + If this is turned off, GDB gdb will handle trampoline functions the
> + same
^^^^^^^
Redundant "gdb" there.
> +@kindex set skip-trampoline-functions @item set
> +skip-trampoline-functions @cindex trampoline functions @cindex
> +stepping through trampoline functions @itemx set
> +skip-trampoline-functions on When calling a function in any language,
> +some compilers might generate so-called trampoline functions, which
> +wrap the actual function call (the
"trampoline functions" should be in @dfn, as you are introducing new terminology here.
> + add_setshow_boolean_cmd ("skip-trampoline-functions", class_run,
> + &skip_trampoline_functions, _("\ Set whether gdb attempts to
> +hide trampolines marked in the debug info."), _("\ Show whether gdb
> +attempts to hide trampolines marked in the debug info."), _("\ If on,
> +while stepping gdb will skip through functions and inlined
> +functions\n\ marked as trampolines by the compiler. If off, gdb will
> +ignore such function\n\ trampolines."),
In the last sentence, I think "ignore such function trampolines" is misleading. I suggest to replace this with "treat trampolines as normal functions".
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 18+ messages in thread
end of thread, other threads:[~2024-03-28 14:32 UTC | newest]
Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-03-28 12:05 [PATCH v6 00/10] GDB support for DW_AT_trampoline Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 01/10] gdb, dwarf: add support for DW_AT_trampoline in DWARF reader Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 02/10] gdb/symtab: add lookup for trampoline functions Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 03/10] gdb: handle stepping through functions with DW_AT_trampoline Abdul Basit Ijaz
2024-03-28 13:58 ` Eli Zaretskii
2024-03-28 14:31 ` Ijaz, Abdul B
2024-03-28 12:05 ` [PATCH v6 04/10] gdb: Skip trampoline frames for the backtrace command Abdul Basit Ijaz
2024-03-28 12:05 ` [PATCH v6 05/10] gdb: Skip trampoline functions for the finish and reverse-finish commands Abdul Basit Ijaz
2024-03-28 13:59 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 06/10] gdb: Skip trampoline functions for the up command Abdul Basit Ijaz
2024-03-28 14:01 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 07/10] gdb: Skip trampoline functions for the return command Abdul Basit Ijaz
2024-03-28 14:01 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 08/10] gdb, mi: Skip trampoline functions for the -stack-list-frames command Abdul Basit Ijaz
2024-03-28 14:02 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 09/10] gdb, mi: Skip trampoline functions for the -stack-list-arguments command Abdul Basit Ijaz
2024-03-28 14:03 ` Eli Zaretskii
2024-03-28 12:05 ` [PATCH v6 10/10] gdb: Filter trampoline frames in backtrace when using Python frame-filters Abdul Basit Ijaz
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