From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) by sourceware.org (Postfix) with ESMTPS id 661C4385BF83 for ; Tue, 31 Mar 2020 19:19:26 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 661C4385BF83 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=scottlinder.com Authentication-Results: sourceware.org; spf=none smtp.mailfrom=scott@scottlinder.com X-Originating-IP: 73.69.18.64 Received: from localhost.localdomain (c-73-69-18-64.hsd1.ma.comcast.net [73.69.18.64]) (Authenticated sender: scott@scottlinder.com) by relay2-d.mail.gandi.net (Postfix) with ESMTPA id B404840004; Tue, 31 Mar 2020 19:19:21 +0000 (UTC) From: Scott Linder To: gdb-patches@sourceware.org Subject: [PATCH v2] [gdb] Support frames inlined into the outer frame Date: Tue, 31 Mar 2020 15:18:56 -0400 Message-Id: <20200331191856.31222-1-scott@scottlinder.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <41baeec4e477b1287e331e58adb9abf4@scottlinder.com> References: <41baeec4e477b1287e331e58adb9abf4@scottlinder.com> X-Spam-Status: No, score=-28.4 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 Mar 2020 19:19:42 -0000 Broaden the definition of `outer_frame_id` to effectively create a new class of "invalid" IDs to represent frames inlined into the outer frame. These new IDs behave like the outer frame, in that they are "invalid", yet return true from `frame_id_p` and compare equal to themselves. 2020-03-18 Scott Linder * frame.c (frame_id_p): Consider functions inlined into outer frame as valid. (frame_id_eq): Consider functions inlined into outer frame with same artificial_depth as equal. (outer_frame_id_p): New. * frame.h (outer_frame_id): Update comment. (outer_frame_id_p): New. * inline-frame.c (inline_frame_this_id): Remove assert that prevents inline frame ids in outer frame. Change-Id: I8aa129c667dccc31590ffdf426586418493a6ebe --- Changes since v1: * Fix ChangeLog formatting. * Add outer_frame_id_p to capture new definition of outer_frame_id in one place and to restore checks for all members. * Reword some comments to make them more precise, borrowing a lot of wording from Andrew Burgess. * Remove some comments describing what is now obvious. * Undo update to frame_id_p comment which exposes implementation details. gdb/frame.c | 41 ++++++++++++++++++++++++++++------------- gdb/frame.h | 12 +++++++++++- gdb/inline-frame.c | 4 ---- 3 files changed, 39 insertions(+), 18 deletions(-) diff --git a/gdb/frame.c b/gdb/frame.c index d74d1d5c7c..c6154c2d9c 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -692,11 +692,7 @@ frame_id_p (struct frame_id l) { int p; - /* The frame is valid iff it has a valid stack address. */ - p = l.stack_status != FID_STACK_INVALID; - /* outer_frame_id is also valid. */ - if (!p && memcmp (&l, &outer_frame_id, sizeof (l)) == 0) - p = 1; + p = l.stack_status != FID_STACK_INVALID || outer_frame_id_p (l); if (frame_debug) { fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l="); @@ -720,14 +716,15 @@ frame_id_eq (struct frame_id l, struct frame_id r) { int eq; - if (l.stack_status == FID_STACK_INVALID && l.special_addr_p - && r.stack_status == FID_STACK_INVALID && r.special_addr_p) - /* The outermost frame marker is equal to itself. This is the - dodgy thing about outer_frame_id, since between execution steps - we might step into another function - from which we can't - unwind either. More thought required to get rid of - outer_frame_id. */ - eq = 1; + if (outer_frame_id_p (l) && outer_frame_id_p (r)) + /* The outermost frame marker, and any inline frame markers derived + from it (with artificial_depth > 0), are equal to themselves. The + problem with outer_frame_id is that, if between execution steps, we + step into a completely separate function (not an inlined function) + that also identifies as outer_frame_id, then we can't distinguish + between the previous frame and the new frame. More thought is + required to get rid of outer_frame_id. */ + eq = l.artificial_depth == r.artificial_depth; else if (l.stack_status == FID_STACK_INVALID || r.stack_status == FID_STACK_INVALID) /* Like a NaN, if either ID is invalid, the result is false. @@ -763,6 +760,24 @@ frame_id_eq (struct frame_id l, struct frame_id r) return eq; } +int +outer_frame_id_p (struct frame_id l) +{ + int p; + + /* The artificial_depth can vary so we ignore it when checking if this is + an outer_frame_id. */ + l.artificial_depth = 0; + p = memcmp (&l, &outer_frame_id, sizeof (outer_frame_id)); + if (frame_debug) + { + fprintf_unfiltered (gdb_stdlog, "{ outer_frame_id_p (l="); + fprint_frame_id (gdb_stdlog, l); + fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p); + } + return p; +} + /* Safety net to check whether frame ID L should be inner to frame ID R, according to their stack addresses. diff --git a/gdb/frame.h b/gdb/frame.h index cfc15022ed..66f19c91dc 100644 --- a/gdb/frame.h +++ b/gdb/frame.h @@ -195,7 +195,13 @@ extern const struct frame_id sentinel_frame_id; /* This means "there is no frame ID, but there is a frame". It should be replaced by best-effort frame IDs for the outermost frame, somehow. - The implementation is only special_addr_p set. */ + + The implementation has stack_status set to FID_STACK_INVALID, + special_addr_p set to 1, artificial_depth set to 0 or greater, and all other + members set to 0. For the non-inline outer frame artificial_depth remains + set to 0 and for frames inlined into it the artificial_depth is set in the + typical way. Checking if a frame marker is an outer_frame_id should be done + with outer_frame_id_p. */ extern const struct frame_id outer_frame_id; /* Flag to control debugging. */ @@ -250,6 +256,10 @@ extern int frame_id_artificial_p (struct frame_id l); either L or R have a zero .func, then the same frame base. */ extern int frame_id_eq (struct frame_id l, struct frame_id r); +/* Returns non-zero when L is an outer frame marker or any inline frame marker + derived from it. */ +extern int outer_frame_id_p (struct frame_id l); + /* Write the internal representation of a frame ID on the specified stream. */ extern void fprint_frame_id (struct ui_file *file, struct frame_id id); diff --git a/gdb/inline-frame.c b/gdb/inline-frame.c index c650195e57..a187630840 100644 --- a/gdb/inline-frame.c +++ b/gdb/inline-frame.c @@ -171,10 +171,6 @@ inline_frame_this_id (struct frame_info *this_frame, frame"). This will take work. */ gdb_assert (frame_id_p (*this_id)); - /* For now, require we don't match outer_frame_id either (see - comment above). */ - gdb_assert (!frame_id_eq (*this_id, outer_frame_id)); - /* Future work NOTE: Alexandre Oliva applied a patch to GCC 4.3 which generates DW_AT_entry_pc for inlined functions when possible. If this attribute is available, we should use it -- 2.17.1