From FEDORA_PATCHES Mon Sep 17 00:00:00 2001 From: Kevin Buettner Date: Wed, 3 May 2023 11:28:24 -0700 Subject: gdb-rhbz2192105-ftbs-dangling-pointer MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ;; Backport upstream patch fixing a "dangling pointer" build problem ;; first seen when building with GCC 13.1.1 20230426 (Red Hat ;; 13.1.1-1). Pass const frame_info_ptr reference for skip_[language_]trampoline 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::push_empty(T&) [with T = frame_info_ptr; AsNode = intrusive_base_node]’, inlined from ‘void intrusive_list::push_back(reference) [with T = frame_info_ptr; AsNode = intrusive_base_node]’ 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 ‘’ in ‘frame_info_ptr::frame_list.intrusive_list::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: ‘’ 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_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 Reviewed-by: Kevin Buettner Reviewed-by: Tom Tromey diff --git a/gdb/c-lang.c b/gdb/c-lang.c --- a/gdb/c-lang.c +++ b/gdb/c-lang.c @@ -1003,7 +1003,7 @@ class cplus_language : public language_defn /* 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); diff --git a/gdb/language.c b/gdb/language.c --- a/gdb/language.c +++ b/gdb/language.c @@ -528,7 +528,7 @@ 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) { diff --git a/gdb/language.h b/gdb/language.h --- a/gdb/language.h +++ b/gdb/language.h @@ -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; } @@ -789,7 +789,7 @@ 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 demangled language symbol, or NULL. */ extern gdb::unique_xmalloc_ptr language_demangle diff --git a/gdb/objc-lang.c b/gdb/objc-lang.c --- a/gdb/objc-lang.c +++ b/gdb/objc-lang.c @@ -282,7 +282,7 @@ class objc_language : public language_defn /* 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);