From: Nils-Christian Kempke <nils-christian.kempke@intel.com>
To: gdb-patches@sourceware.org
Subject: [PATCH 2/3] gdb/symtab: add lookup for trampoline functions
Date: Thu, 7 Jul 2022 14:15:37 +0200 [thread overview]
Message-ID: <20220707121538.1317473-3-nils-christian.kempke@intel.com> (raw)
In-Reply-To: <20220707121538.1317473-2-nils-christian.kempke@intel.com>
In order to queriy 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.
gdb/ChangeLog:
2022-05-30 Nils-Christian Kempke <nils-christian.kempke@intel.com>
* symtab.h (in_trampoline_function): New function
(find_function_trampoline_target): New function.
* symtab.c (in_trampoline_function): New function implementation.
(find_function_trampoline_target): New implementation of
trampoline target lookup.
Signed-off-by: Nils-Christian Kempke <nils-christian.kempke@intel.com>
---
gdb/symtab.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/symtab.h | 14 ++++++++++++++
2 files changed, 67 insertions(+)
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 03aa2a96b87..a7ea928623b 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -72,6 +72,7 @@
#include "gdbsupport/gdb_string_view.h"
#include "gdbsupport/pathstuff.h"
#include "gdbsupport/common-utils.h"
+#include "gdbsupport/symbol.h"
/* Forward declarations for local functions. */
@@ -4144,6 +4145,58 @@ 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_PHYSNAME)
+ {
+ /* Handle both the mangled and demangled PHYSNAME. */
+ const char *physname = trampoline->target_physname ();
+
+ if (find_minimal_symbol_address (physname, &target_address, nullptr)
+ != 0)
+ target_address = 0;
+ }
+ else if (trampoline->target_kind () == TRAMPOLINE_TARGET_PHYSADDR)
+ {
+ /* 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 = trampoline->target_physaddr ()
+ + 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 ac902a4cbbe..7dad0ddba9f 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -2244,6 +2244,20 @@ extern const struct gnu_ifunc_fns *gnu_ifunc_fns_p;
extern CORE_ADDR find_solib_trampoline_target (struct frame_info *, CORE_ADDR);
+/* Return wether 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. */
--
2.25.1
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next prev parent reply other threads:[~2022-07-07 12:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-07 12:15 [PATCH 1/3] gdb: add support for DW_AT_trampoline in DWARF reader Nils-Christian Kempke
2022-07-07 12:15 ` Nils-Christian Kempke [this message]
2022-07-15 20:13 ` [PATCH 2/3] gdb/symtab: add lookup for trampoline functions Tom Tromey
2022-07-07 12:15 ` [PATCH 3/3] gdb/infrun: handle stepping through functions with DW_AT_trampoline Nils-Christian Kempke
2022-07-15 20:20 ` Tom Tromey
2022-07-13 7:39 ` [PATCH 1/3] gdb: add support for DW_AT_trampoline in DWARF reader George, Jini Susan
2022-07-13 11:59 ` Kempke, Nils-Christian
2022-07-17 12:57 ` George, Jini Susan
2022-07-18 16:11 ` Tom Tromey
2022-07-15 20:05 ` Tom Tromey
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