From e961aad01fb3db2cfb0579ac387a4e24739cd0e5 Mon Sep 17 00:00:00 2001 From: Guinevere Larsen Date: Thu, 18 Jan 2024 14:25:14 +0100 Subject: [PATCH] gdb: make gdbarch store a vector of frame unwinders 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 1faa013c16f..8b8d67ed8f8 100644 --- a/gdb/arch-utils.c +++ b/gdb/arch-utils.c @@ -1218,6 +1218,14 @@ obstack *gdbarch_obstack (gdbarch *arch) /* See gdbarch.h. */ +std::vector& +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 27aa9e10677..877f1e51309 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 +/* If an unwinder should be prepended to the list, this is the + index in which it should be inserted. */ +static int osabi_start = -1; + +/* Start the table out with a few default sniffers. OSABI code + can't override this. */ +static void +initialize_frame_unwind_table (std::vector& table) { - 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; -}; - -static const registry::key - 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) -{ - 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& +get_frame_unwind_table (struct gdbarch *gdbarch) +{ + std::vector& 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; + std::vector& table = get_frame_unwind_table (gdbarch); - /* 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; + 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& 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 (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 (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 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 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 b9be3948d1e..61732a01053 100644 --- a/gdb/gdbarch.c +++ b/gdb/gdbarch.c @@ -27,6 +27,7 @@ /* Maintain the struct gdbarch object. */ +#include struct gdbarch { /* Has this architecture been fully initialized? */ @@ -36,6 +37,8 @@ struct gdbarch auto_obstack obstack; /* Registry. */ registry registry_fields; + /* list of frame unwinders. */ + std::vector 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 (gdbarch_obstack ((GDBARCH))) +/* Return the vector of unwinders stored in a gdbarch object. */ + +std::vector& 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..891b2a46ef5 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 ",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 registry_fields;", file=f) + print(" /* list of frame unwinders. */", file=f) + print(" std::vector unwinders;", file=f) print(file=f) print(" /* basic architectural information. */", file=f) for c in filter(info, components):