From: Guinevere Larsen <blarsen@redhat.com>
To: gdb-patches@sourceware.org
Cc: Guinevere Larsen <blarsen@redhat.com>
Subject: [PATCH 1/4] gdb: make gdbarch store a vector of frame unwinders
Date: Wed, 6 Mar 2024 13:51:32 +0100 [thread overview]
Message-ID: <20240306125135.766567-2-blarsen@redhat.com> (raw)
In-Reply-To: <20240306125135.766567-1-blarsen@redhat.com>
Before this commit, all frame unwinders would be stored in the obstack
of a gdbarch and accessed by using the registry system. This made for
unwieldy code, and unnecessarily complex logic in the frame_unwinder
implementation, along with making frame_unwind structs be unable to have
non-trivial constructors.
Seeing as a future patch of this series wants to refactor the
frame_unwind struct to use inheritance, obstack storage would no longer
be viable. In preparation for that change, this commit adds an
std::vector to gdbarch to store the unwinders in.
There should be no user-visible changes.
---
gdb/arch-utils.c | 8 ++++
gdb/frame-unwind.c | 111 +++++++++++++++++----------------------------
gdb/gdbarch.c | 3 ++
gdb/gdbarch.h | 5 ++
gdb/gdbarch.py | 3 ++
5 files changed, 61 insertions(+), 69 deletions(-)
diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index ae3354f6579..30693d84c8d 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -1219,6 +1219,14 @@ obstack *gdbarch_obstack (gdbarch *arch)
/* See gdbarch.h. */
+std::vector<const frame_unwind*>&
+gdbarch_get_unwinder_list (struct gdbarch *arch)
+{
+ return arch->unwinders;
+}
+
+/* See gdbarch.h. */
+
char *
gdbarch_obstack_strdup (struct gdbarch *arch, const char *string)
{
diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c
index e9983a9fd74..27d84981d89 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -31,49 +31,16 @@
#include "cli/cli-cmds.h"
#include "inferior.h"
-struct frame_unwind_table_entry
-{
- const struct frame_unwind *unwinder;
- struct frame_unwind_table_entry *next;
-};
-
-struct frame_unwind_table
-{
- struct frame_unwind_table_entry *list = nullptr;
- /* The head of the OSABI part of the search list. */
- struct frame_unwind_table_entry **osabi_head = nullptr;
-};
+/* If an unwinder should be prepended to the list, this is the
+ index in which it should be inserted. */
+static int osabi_start = -1;
-static const registry<gdbarch>::key<struct frame_unwind_table>
- frame_unwind_data;
-
-/* A helper function to add an unwinder to a list. LINK says where to
- install the new unwinder. The new link is returned. */
-
-static struct frame_unwind_table_entry **
-add_unwinder (struct obstack *obstack, const struct frame_unwind *unwinder,
- struct frame_unwind_table_entry **link)
-{
- *link = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
- (*link)->unwinder = unwinder;
- return &(*link)->next;
-}
-
-static struct frame_unwind_table *
-get_frame_unwind_table (struct gdbarch *gdbarch)
+/* Start the table out with a few default sniffers. OSABI code
+ can't override this. */
+static void
+initialize_frame_unwind_table (std::vector<const frame_unwind*>& table)
{
- struct frame_unwind_table *table = frame_unwind_data.get (gdbarch);
- if (table != nullptr)
- return table;
-
- table = new frame_unwind_table;
-
- /* Start the table out with a few default sniffers. OSABI code
- can't override this. */
- struct frame_unwind_table_entry **link = &table->list;
-
- struct obstack *obstack = gdbarch_obstack (gdbarch);
- link = add_unwinder (obstack, &dummy_frame_unwind, link);
+ table.push_back (&dummy_frame_unwind);
/* The DWARF tailcall sniffer must come before the inline sniffer.
Otherwise, we can end up in a situation where a DWARF frame finds
tailcall information, but then the inline sniffer claims a frame
@@ -81,12 +48,22 @@ get_frame_unwind_table (struct gdbarch *gdbarch)
safe to do always because the tailcall sniffer can only ever be
activated if the newer frame was created using the DWARF
unwinder, and it also found tailcall information. */
- link = add_unwinder (obstack, &dwarf2_tailcall_frame_unwind, link);
- link = add_unwinder (obstack, &inline_frame_unwind, link);
+ table.push_back (&dwarf2_tailcall_frame_unwind);
+ table.push_back (&inline_frame_unwind);
/* The insertion point for OSABI sniffers. */
- table->osabi_head = link;
- frame_unwind_data.set (gdbarch, table);
+ osabi_start = table.size ();
+}
+
+/* This function call retrieves the list of frame unwinders available in
+ GDBARCH. If this list is empty, it is initialized before being
+ returned. */
+static std::vector<const frame_unwind*>&
+get_frame_unwind_table (struct gdbarch *gdbarch)
+{
+ std::vector<const frame_unwind*>& table = gdbarch_get_unwinder_list (gdbarch);
+ if (table.size () == 0)
+ initialize_frame_unwind_table (table);
return table;
}
@@ -95,27 +72,25 @@ void
frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
const struct frame_unwind *unwinder)
{
- struct frame_unwind_table *table = get_frame_unwind_table (gdbarch);
- struct frame_unwind_table_entry *entry;
-
- /* Insert the new entry at the start of the list. */
- entry = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
- entry->unwinder = unwinder;
- entry->next = (*table->osabi_head);
- (*table->osabi_head) = entry;
+ std::vector<const frame_unwind*>& table = get_frame_unwind_table (gdbarch);
+
+ gdb_assert (osabi_start >= 0);
+
+ table.push_back (unwinder);
+
+ /* Bubble the new entry up to where new unwinders are allowed to be
+ inserterd. */
+ for (int i = table.size() - 1; i > osabi_start; i--)
+ std::swap(table[i], table[i-1]);
}
void
frame_unwind_append_unwinder (struct gdbarch *gdbarch,
const struct frame_unwind *unwinder)
{
- struct frame_unwind_table *table = get_frame_unwind_table (gdbarch);
- struct frame_unwind_table_entry **ip;
+ std::vector<const frame_unwind*>& table = get_frame_unwind_table (gdbarch);
- /* Find the end of the list and insert the new entry there. */
- for (ip = table->osabi_head; (*ip) != NULL; ip = &(*ip)->next);
- (*ip) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
- (*ip)->unwinder = unwinder;
+ table.push_back (unwinder);
}
/* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for
@@ -188,9 +163,6 @@ frame_unwind_find_by_frame (const frame_info_ptr &this_frame, void **this_cache)
FRAME_SCOPED_DEBUG_ENTER_EXIT;
frame_debug_printf ("this_frame=%d", frame_relative_level (this_frame));
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- struct frame_unwind_table *table = get_frame_unwind_table (gdbarch);
- struct frame_unwind_table_entry *entry;
const struct frame_unwind *unwinder_from_target;
unwinder_from_target = target_get_unwinder ();
@@ -205,8 +177,10 @@ frame_unwind_find_by_frame (const frame_info_ptr &this_frame, void **this_cache)
unwinder_from_target))
return;
- for (entry = table->list; entry != NULL; entry = entry->next)
- if (frame_unwind_try_unwinder (this_frame, this_cache, entry->unwinder))
+ struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ std::vector<const frame_unwind*> table = get_frame_unwind_table (gdbarch);
+ for (auto unwinder: table)
+ if (frame_unwind_try_unwinder (this_frame, this_cache, unwinder))
return;
internal_error (_("frame_unwind_find_by_frame failed"));
@@ -347,7 +321,7 @@ static void
maintenance_info_frame_unwinders (const char *args, int from_tty)
{
gdbarch *gdbarch = current_inferior ()->arch ();
- struct frame_unwind_table *table = get_frame_unwind_table (gdbarch);
+ std::vector<const frame_unwind*> table = get_frame_unwind_table (gdbarch);
ui_out *uiout = current_uiout;
ui_out_emit_table table_emitter (uiout, 2, -1, "FrameUnwinders");
@@ -355,11 +329,10 @@ maintenance_info_frame_unwinders (const char *args, int from_tty)
uiout->table_header (25, ui_left, "type", "Type");
uiout->table_body ();
- for (struct frame_unwind_table_entry *entry = table->list; entry != NULL;
- entry = entry->next)
+ for (const struct frame_unwind* unwinder: table)
{
- const char *name = entry->unwinder->name;
- const char *type = frame_type_str (entry->unwinder->type);
+ const char *name = unwinder->name;
+ const char *type = frame_type_str (unwinder->type);
ui_out_emit_list tuple_emitter (uiout, nullptr);
uiout->field_string ("name", name);
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index 80a04bf0caf..fe88f19dc7f 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -27,6 +27,7 @@
/* Maintain the struct gdbarch object. */
+#include <vector>
struct gdbarch
{
/* Has this architecture been fully initialized? */
@@ -36,6 +37,8 @@ struct gdbarch
auto_obstack obstack;
/* Registry. */
registry<gdbarch> registry_fields;
+ /* list of frame unwinders. */
+ std::vector<const frame_unwind *> unwinders;
/* basic architectural information. */
const struct bfd_arch_info * bfd_arch_info;
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 77d3406779f..1434d61e600 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -30,6 +30,7 @@
#include "displaced-stepping.h"
#include "gdbsupport/gdb-checked-static-cast.h"
#include "registry.h"
+#include "frame-unwind.h"
struct floatformat;
struct ui_file;
@@ -310,6 +311,10 @@ extern obstack *gdbarch_obstack (gdbarch *arch);
#define GDBARCH_OBSTACK_ZALLOC(GDBARCH, TYPE) obstack_zalloc<TYPE> (gdbarch_obstack ((GDBARCH)))
+/* Return the vector of unwinders stored in a gdbarch object. */
+
+std::vector<const frame_unwind*>& gdbarch_get_unwinder_list (struct gdbarch *arch);
+
/* Duplicate STRING, returning an equivalent string that's allocated on the
obstack associated with GDBARCH. The string is freed when the corresponding
architecture is also freed. */
diff --git a/gdb/gdbarch.py b/gdb/gdbarch.py
index 4b4db667ca4..bff66cc39d3 100755
--- a/gdb/gdbarch.py
+++ b/gdb/gdbarch.py
@@ -125,6 +125,7 @@ with open("gdbarch.c", "w") as f:
print(file=f)
print("/* Maintain the struct gdbarch object. */", file=f)
print(file=f)
+ print("#include <vector>", file=f)
#
# The struct definition body.
#
@@ -137,6 +138,8 @@ with open("gdbarch.c", "w") as f:
print(" auto_obstack obstack;", file=f)
print(" /* Registry. */", file=f)
print(" registry<gdbarch> registry_fields;", file=f)
+ print(" /* list of frame unwinders. */", file=f)
+ print(" std::vector<const frame_unwind *> unwinders;", file=f)
print(file=f)
print(" /* basic architectural information. */", file=f)
for c in filter(info, components):
--
2.43.2
next prev parent reply other threads:[~2024-03-06 12:51 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-06 12:51 [PATCH 0/4] Modernize frame unwinders and add disable feature Guinevere Larsen
2024-03-06 12:51 ` Guinevere Larsen [this message]
2024-03-08 16:34 ` [PATCH 1/4] gdb: make gdbarch store a vector of frame unwinders Tom Tromey
2024-03-11 10:51 ` Guinevere Larsen
2024-03-11 18:01 ` Tom Tromey
2024-03-06 12:51 ` [PATCH 2/4] gdb: add "unwinder class" to " Guinevere Larsen
2024-03-08 16:40 ` Tom Tromey
2024-03-06 12:51 ` [PATCH 3/4] gdb: Migrate frame unwinders to use C++ classes Guinevere Larsen
2024-03-07 11:01 ` Lancelot SIX
2024-03-07 11:04 ` Guinevere Larsen
2024-03-08 17:07 ` Tom Tromey
2024-03-12 16:24 ` Guinevere Larsen
2024-03-06 12:51 ` [PATCH 4/4] GDB: introduce ability to disable frame unwinders Guinevere Larsen
2024-03-06 13:47 ` Eli Zaretskii
2024-03-06 14:07 ` Guinevere Larsen
2024-03-06 14:16 ` Eli Zaretskii
2024-03-08 17:22 ` Tom Tromey
2024-03-11 14:09 ` Guinevere Larsen
2024-03-11 14:56 ` [PATCH 0/4] Modernize frame unwinders and add disable feature Luis Machado
2024-03-11 15:00 ` Guinevere Larsen
2024-03-11 15:10 ` Luis Machado
2024-03-13 12:08 ` Guinevere Larsen
2024-03-13 12:44 ` Luis Machado
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