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Pass const frame_info_ptr reference for skip_[language_]trampoline

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g++ 13.1.1 produces a -Werror=dangling-pointer=

In file included from ../../binutils-gdb/gdb/frame.h:75,
                 from ../../binutils-gdb/gdb/symtab.h:40,
                 from ../../binutils-gdb/gdb/language.c:33:
In member function ‘void intrusive_list<T, AsNode>::push_empty(T&) [with T = frame_info_ptr; AsNode = intrusive_base_node<frame_info_ptr>]’,
    inlined from ‘void intrusive_list<T, AsNode>::push_back(reference) [with T = frame_info_ptr; AsNode = intrusive_base_node<frame_info_ptr>]’ at gdbsupport/intrusive_list.h:332:24,
    inlined from ‘frame_info_ptr::frame_info_ptr(const frame_info_ptr&)’ at gdb/frame.h:241:26,
    inlined from ‘CORE_ADDR skip_language_trampoline(frame_info_ptr, CORE_ADDR)’ at gdb/language.c:530:49:
gdbsupport/intrusive_list.h:415:12: error: storing the address of local variable ‘<anonymous>’ in ‘frame_info_ptr::frame_list.intrusive_list<frame_info_ptr>::m_back’ [-Werror=dangling-pointer=]
  415 |     m_back = &elem;
      |     ~~~~~~~^~~~~~~
gdb/language.c: In function ‘CORE_ADDR skip_language_trampoline(frame_info_ptr, CORE_ADDR)’:
gdb/language.c:530:49: note: ‘<anonymous>’ declared here
  530 |       CORE_ADDR real_pc = lang->skip_trampoline (frame, pc);
      |                           ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
gdb/frame.h:359:41: note: ‘frame_info_ptr::frame_list’ declared here
  359 |   static intrusive_list<frame_info_ptr> frame_list;
      |                                         ^~~~~~~~~~

Each new frame_info_ptr is being pushed on a static frame list and g++
cannot see why that is safe in case the frame_info_ptr is created and
destroyed immediately when passed as value.

It isn't clear why only in this one place g++ sees the issue (probably
because it can inline enough code in this specific case).

Since passing the frame_info_ptr as const reference is cheaper, use
that as workaround for this warning.

PR build/30413
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30413

Tested-by: Kevin Buettner <kevinb@redhat.com>
Reviewed-by: Kevin Buettner <kevinb@redhat.com>
Reviewed-by: Tom Tromey <tom@tromey.com>
This commit is contained in:
Mark Wielaard 2023-05-02 20:23:32 +02:00
parent 7e1b588764
commit 9b0ccb1eba
4 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
gdb/c-lang.c
View File

@ -1002,7 +1002,7 @@ public:
/* See language.h. */
CORE_ADDR skip_trampoline (frame_info_ptr fi,
CORE_ADDR skip_trampoline (const frame_info_ptr &fi,
CORE_ADDR pc) const override
{
return cplus_skip_trampoline (fi, pc);

2
gdb/language.c
View File

@ -523,7 +523,7 @@ add_set_language_command ()
Return the result from the first that returns non-zero, or 0 if all
`fail'. */
CORE_ADDR
skip_language_trampoline (frame_info_ptr frame, CORE_ADDR pc)
skip_language_trampoline (const frame_info_ptr &frame, CORE_ADDR pc)
{
for (const auto &lang : language_defn::languages)
{

4
gdb/language.h
View File

@ -471,7 +471,7 @@ struct language_defn
If that PC falls in a trampoline belonging to this language, return
the address of the first pc in the real function, or 0 if it isn't a
language tramp for this language. */
virtual CORE_ADDR skip_trampoline (frame_info_ptr fi, CORE_ADDR pc) const
virtual CORE_ADDR skip_trampoline (const frame_info_ptr &fi, CORE_ADDR pc) const
{
return (CORE_ADDR) 0;
}
@ -790,7 +790,7 @@ extern const char *language_str (enum language);
/* Check for a language-specific trampoline. */
extern CORE_ADDR skip_language_trampoline (frame_info_ptr, CORE_ADDR pc);
extern CORE_ADDR skip_language_trampoline (const frame_info_ptr &, CORE_ADDR pc);
/* Return information about whether TYPE should be passed
(and returned) by reference at the language level. */

2
gdb/objc-lang.c
View File

@ -282,7 +282,7 @@ public:
/* See language.h. */
CORE_ADDR skip_trampoline (frame_info_ptr frame,
CORE_ADDR skip_trampoline (const frame_info_ptr &frame,
CORE_ADDR stop_pc) const override
{
struct gdbarch *gdbarch = get_frame_arch (frame);