gdb/
Add forgotten gdb/dwarf2-frame-tailcall.c. Add forgotten gdb/dwarf2-frame-tailcall.h.
This commit is contained in:
Jan Kratochvil
parent
2bda9cc5ee
commit
e1b16eb466
479
gdb/dwarf2-frame-tailcall.c
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479
gdb/dwarf2-frame-tailcall.c
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@ -0,0 +1,479 @@
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/* Virtual tail call frames unwinder for GDB.
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Copyright (C) 2010, 2011 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "gdb_assert.h"
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#include "frame.h"
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#include "dwarf2-frame-tailcall.h"
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#include "dwarf2loc.h"
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#include "frame-unwind.h"
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#include "block.h"
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#include "hashtab.h"
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#include "exceptions.h"
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#include "gdbtypes.h"
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#include "regcache.h"
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#include "value.h"
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/* Contains struct tailcall_cache indexed by next_bottom_frame. */
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static htab_t cache_htab;
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/* Associate structure of the unwinder to call_site_chain. Lifetime of this
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structure is maintained by REFC decremented by dealloc_cache, all of them
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get deleted during reinit_frame_cache. */
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struct tailcall_cache
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{
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/* It must be the first one of this struct. It is the furthest callee. */
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struct frame_info *next_bottom_frame;
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/* Reference count. The whole chain of virtual tail call frames shares one
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tailcall_cache. */
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int refc;
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/* Associated found virtual taill call frames chain, it is never NULL. */
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struct call_site_chain *chain;
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/* Cached pretended_chain_levels result. */
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int chain_levels;
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/* Unwound PC from the top (caller) frame, as it is not contained
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in CHAIN. */
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CORE_ADDR prev_pc;
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/* Compensate SP in caller frames appropriately. prev_sp and
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entry_cfa_sp_offset are valid only if PREV_SP_P. PREV_SP is SP at the top
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(caller) frame. ENTRY_CFA_SP_OFFSET is shift of SP in tail call frames
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against next_bottom_frame SP. */
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unsigned prev_sp_p : 1;
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CORE_ADDR prev_sp;
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LONGEST entry_cfa_sp_offset;
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};
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/* hash_f for htab_create_alloc of cache_htab. */
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static hashval_t
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cache_hash (const void *arg)
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{
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const struct tailcall_cache *cache = arg;
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return htab_hash_pointer (cache->next_bottom_frame);
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}
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/* eq_f for htab_create_alloc of cache_htab. */
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static int
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cache_eq (const void *arg1, const void *arg2)
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{
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const struct tailcall_cache *cache1 = arg1;
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const struct tailcall_cache *cache2 = arg2;
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return cache1->next_bottom_frame == cache2->next_bottom_frame;
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}
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/* Create new tailcall_cache for NEXT_BOTTOM_FRAME, NEXT_BOTTOM_FRAME must not
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yet have been indexed by cache_htab. Caller holds one reference of the new
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tailcall_cache. */
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static struct tailcall_cache *
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cache_new_ref1 (struct frame_info *next_bottom_frame)
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{
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struct tailcall_cache *cache;
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void **slot;
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cache = xzalloc (sizeof (*cache));
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cache->next_bottom_frame = next_bottom_frame;
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cache->refc = 1;
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slot = htab_find_slot (cache_htab, cache, INSERT);
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gdb_assert (*slot == NULL);
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*slot = cache;
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return cache;
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}
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/* Create new reference to CACHE. */
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static void
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cache_ref (struct tailcall_cache *cache)
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{
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gdb_assert (cache->refc > 0);
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cache->refc++;
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}
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/* Drop reference to CACHE, possibly fully freeing it and unregistering it from
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cache_htab. */
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static void
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cache_unref (struct tailcall_cache *cache)
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{
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gdb_assert (cache->refc > 0);
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if (!--cache->refc)
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{
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gdb_assert (htab_find_slot (cache_htab, cache, NO_INSERT) != NULL);
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htab_remove_elt (cache_htab, cache);
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xfree (cache->chain);
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xfree (cache);
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}
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}
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/* Return 1 if FI is a non-bottom (not the callee) tail call frame. Otherwise
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return 0. */
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static int
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frame_is_tailcall (struct frame_info *fi)
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{
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return frame_unwinder_is (fi, &dwarf2_tailcall_frame_unwind);
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}
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/* Try to find tailcall_cache in cache_htab if FI is a part of its virtual tail
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call chain. Otherwise return NULL. No new reference is created. */
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static struct tailcall_cache *
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cache_find (struct frame_info *fi)
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{
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struct tailcall_cache *cache;
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void **slot;
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while (frame_is_tailcall (fi))
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{
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fi = get_next_frame (fi);
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gdb_assert (fi != NULL);
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}
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slot = htab_find_slot (cache_htab, &fi, NO_INSERT);
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if (slot == NULL)
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return NULL;
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cache = *slot;
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gdb_assert (cache != NULL);
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return cache;
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}
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/* Number of virtual frames between THIS_FRAME and CACHE->NEXT_BOTTOM_FRAME.
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If THIS_FRAME is CACHE-> NEXT_BOTTOM_FRAME return -1. */
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static int
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existing_next_levels (struct frame_info *this_frame,
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struct tailcall_cache *cache)
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{
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int retval = (frame_relative_level (this_frame)
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- frame_relative_level (cache->next_bottom_frame) - 1);
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gdb_assert (retval >= -1);
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return retval;
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}
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/* The number of virtual tail call frames in CHAIN. With no virtual tail call
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frames the function would return 0 (but CHAIN does not exist in such
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case). */
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static int
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pretended_chain_levels (struct call_site_chain *chain)
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{
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int chain_levels;
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gdb_assert (chain != NULL);
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if (chain->callers == chain->length && chain->callees == chain->length)
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return chain->length;
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chain_levels = chain->callers + chain->callees;
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gdb_assert (chain_levels < chain->length);
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return chain_levels;
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}
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/* Implementation of frame_this_id_ftype. THIS_CACHE must be already
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initialized with tailcall_cache, THIS_FRAME must be a part of THIS_CACHE.
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Specific virtual tail call frames are tracked by INLINE_DEPTH. */
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static void
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tailcall_frame_this_id (struct frame_info *this_frame, void **this_cache,
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struct frame_id *this_id)
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{
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struct tailcall_cache *cache = *this_cache;
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struct frame_info *next_frame;
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/* Tail call does not make sense for a sentinel frame. */
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next_frame = get_next_frame (this_frame);
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gdb_assert (next_frame != NULL);
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*this_id = get_frame_id (next_frame);
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(*this_id).code_addr = get_frame_pc (this_frame);
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(*this_id).code_addr_p = 1;
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(*this_id).inline_depth = (cache->chain_levels
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- existing_next_levels (this_frame, cache));
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gdb_assert ((*this_id).inline_depth > 0);
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}
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/* Find PC to be unwound from THIS_FRAME. THIS_FRAME must be a part of
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CACHE. */
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static CORE_ADDR
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pretend_pc (struct frame_info *this_frame, struct tailcall_cache *cache)
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{
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int next_levels = existing_next_levels (this_frame, cache);
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struct call_site_chain *chain = cache->chain;
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int caller_no;
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gdb_assert (chain != NULL);
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next_levels++;
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gdb_assert (next_levels >= 0);
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if (next_levels < chain->callees)
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return chain->call_site[chain->length - next_levels - 1]->pc;
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next_levels -= chain->callees;
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/* Otherwise CHAIN->CALLEES are already covered by CHAIN->CALLERS. */
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if (chain->callees != chain->length)
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{
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if (next_levels < chain->callers)
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return chain->call_site[chain->callers - next_levels - 1]->pc;
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next_levels -= chain->callers;
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}
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gdb_assert (next_levels == 0);
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return cache->prev_pc;
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}
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/* Implementation of frame_prev_register_ftype. If no specific register
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override is supplied NULL is returned (this is incompatible with
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frame_prev_register_ftype semantics). next_bottom_frame and tail call
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frames unwind the NULL case differently. */
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struct value *
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dwarf2_tailcall_prev_register_first (struct frame_info *this_frame,
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void **tailcall_cachep, int regnum)
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{
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struct gdbarch *this_gdbarch = get_frame_arch (this_frame);
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struct tailcall_cache *cache = *tailcall_cachep;
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CORE_ADDR addr;
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if (regnum == gdbarch_pc_regnum (this_gdbarch))
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addr = pretend_pc (this_frame, cache);
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else if (cache->prev_sp_p && regnum == gdbarch_sp_regnum (this_gdbarch))
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{
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int next_levels = existing_next_levels (this_frame, cache);
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if (next_levels == cache->chain_levels - 1)
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addr = cache->prev_sp;
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else
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addr = get_frame_base (this_frame) - cache->entry_cfa_sp_offset;
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}
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else
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return NULL;
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return frame_unwind_got_address (this_frame, regnum, addr);
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}
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/* Implementation of frame_prev_register_ftype for tail call frames. Register
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set of virtual tail call frames is assumed to be the one of the top (caller)
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frame - assume unchanged register value for NULL from
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dwarf2_tailcall_prev_register_first. */
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static struct value *
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tailcall_frame_prev_register (struct frame_info *this_frame,
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void **this_cache, int regnum)
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{
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struct tailcall_cache *cache = *this_cache;
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struct value *val;
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gdb_assert (this_frame != cache->next_bottom_frame);
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val = dwarf2_tailcall_prev_register_first (this_frame, this_cache, regnum);
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if (val)
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return val;
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return frame_unwind_got_register (this_frame, regnum, regnum);
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}
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/* Implementation of frame_sniffer_ftype. It will never find a new chain, use
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dwarf2_tailcall_sniffer_first for the bottom (callee) frame. It will find
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all the predecessing virtual tail call frames, it will return false when
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there exist no more tail call frames in this chain. */
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static int
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tailcall_frame_sniffer (const struct frame_unwind *self,
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struct frame_info *this_frame, void **this_cache)
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{
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struct frame_info *next_frame;
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int next_levels;
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struct tailcall_cache *cache;
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/* Inner tail call element does not make sense for a sentinel frame. */
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next_frame = get_next_frame (this_frame);
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if (next_frame == NULL)
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return 0;
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cache = cache_find (next_frame);
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if (cache == NULL)
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return 0;
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cache_ref (cache);
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next_levels = existing_next_levels (this_frame, cache);
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/* NEXT_LEVELS is -1 only in dwarf2_tailcall_sniffer_first. */
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gdb_assert (next_levels >= 0);
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gdb_assert (next_levels <= cache->chain_levels);
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if (next_levels == cache->chain_levels)
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{
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cache_unref (cache);
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return 0;
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}
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*this_cache = cache;
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return 1;
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}
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/* The initial "sniffer" whether THIS_FRAME is a bottom (callee) frame of a new
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chain to create. Keep TAILCALL_CACHEP NULL if it did not find any chain,
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initialize it otherwise. No tail call chain is created if there are no
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unambiguous virtual tail call frames to report.
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ENTRY_CFA_SP_OFFSETP is NULL if no special SP handling is possible,
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otherwise *ENTRY_CFA_SP_OFFSETP is the number of bytes to subtract from tail
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call frames frame base to get the SP value there - to simulate return
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address pushed on the stack. */
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void
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dwarf2_tailcall_sniffer_first (struct frame_info *this_frame,
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void **tailcall_cachep,
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const LONGEST *entry_cfa_sp_offsetp)
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{
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CORE_ADDR prev_pc = 0, prev_sp = 0; /* GCC warning. */
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int prev_sp_p = 0;
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CORE_ADDR this_pc, pc;
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struct gdbarch *prev_gdbarch;
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struct call_site_chain *chain = NULL;
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struct frame_info *fi;
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struct tailcall_cache *cache;
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volatile struct gdb_exception except;
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gdb_assert (*tailcall_cachep == NULL);
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this_pc = get_frame_pc (this_frame);
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/* Catch any unwinding errors. */
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TRY_CATCH (except, RETURN_MASK_ERROR)
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{
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int pc_regnum, sp_regnum;
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prev_gdbarch = frame_unwind_arch (this_frame);
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pc_regnum = gdbarch_pc_regnum (prev_gdbarch);
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if (pc_regnum == -1)
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break;
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/* Simulate frame_unwind_pc without setting this_frame->prev_pc.p. */
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prev_pc = frame_unwind_register_unsigned (this_frame, pc_regnum);
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/* call_site_find_chain can throw an exception. */
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chain = call_site_find_chain (prev_gdbarch, prev_pc, this_pc);
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if (entry_cfa_sp_offsetp == NULL)
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break;
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sp_regnum = gdbarch_sp_regnum (prev_gdbarch);
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if (sp_regnum == -1)
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break;
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prev_sp = frame_unwind_register_unsigned (this_frame, sp_regnum);
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prev_sp_p = 1;
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}
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if (except.reason < 0)
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{
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if (entry_values_debug)
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exception_print (gdb_stdout, except);
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return;
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}
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/* Ambiguous unwind or unambiguous unwind verified as matching. */
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if (chain == NULL || chain->length == 0)
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{
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xfree (chain);
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return;
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}
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cache = cache_new_ref1 (this_frame);
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*tailcall_cachep = cache;
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cache->chain = chain;
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cache->prev_pc = prev_pc;
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cache->chain_levels = pretended_chain_levels (chain);
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cache->prev_sp_p = prev_sp_p;
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if (cache->prev_sp_p)
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{
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cache->prev_sp = prev_sp;
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cache->entry_cfa_sp_offset = *entry_cfa_sp_offsetp;
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}
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gdb_assert (cache->chain_levels > 0);
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}
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/* Implementation of frame_dealloc_cache_ftype. It can be called even for the
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bottom chain frame from dwarf2_frame_dealloc_cache which is not a real
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TAILCALL_FRAME. */
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static void
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tailcall_frame_dealloc_cache (struct frame_info *self, void *this_cache)
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{
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struct tailcall_cache *cache = this_cache;
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cache_unref (cache);
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}
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/* Implementation of frame_prev_arch_ftype. We assume all the virtual tail
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call frames have gdbarch of the bottom (callee) frame. */
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static struct gdbarch *
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tailcall_frame_prev_arch (struct frame_info *this_frame,
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void **this_prologue_cache)
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{
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struct tailcall_cache *cache = *this_prologue_cache;
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return get_frame_arch (cache->next_bottom_frame);
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}
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/* Virtual tail call frame unwinder if dwarf2_tailcall_sniffer_first finds
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a chain to create. */
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const struct frame_unwind dwarf2_tailcall_frame_unwind =
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{
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TAILCALL_FRAME,
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default_frame_unwind_stop_reason,
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tailcall_frame_this_id,
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tailcall_frame_prev_register,
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NULL,
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tailcall_frame_sniffer,
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tailcall_frame_dealloc_cache,
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tailcall_frame_prev_arch
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};
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/* Provide a prototype to silence -Wmissing-prototypes. */
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extern initialize_file_ftype _initialize_tailcall_frame;
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void
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_initialize_tailcall_frame (void)
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{
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cache_htab = htab_create_alloc (50, cache_hash, cache_eq, NULL, xcalloc,
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xfree);
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}
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39
gdb/dwarf2-frame-tailcall.h
Normal file
39
gdb/dwarf2-frame-tailcall.h
Normal file
@ -0,0 +1,39 @@
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/* Definitions for virtual tail call frames unwinder for GDB.
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Copyright (C) 2010, 2011 Free Software Foundation, Inc.
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||||
|
||||
This file is part of GDB.
|
||||
|
||||
This program is free software; you can redistribute it and/or modify
|
||||
it under the terms of the GNU General Public License as published by
|
||||
the Free Software Foundation; either version 3 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU General Public License
|
||||
along with this program. If not, see <http://www.gnu.org/licenses/>. */
|
||||
|
||||
#ifndef DWARF2_FRAME_TAILCALL_H
|
||||
#define DWARF2_FRAME_TAILCALL_H 1
|
||||
|
||||
struct frame_info;
|
||||
struct frame_unwind;
|
||||
|
||||
/* The tail call frame unwinder. */
|
||||
|
||||
extern void
|
||||
dwarf2_tailcall_sniffer_first (struct frame_info *this_frame,
|
||||
void **tailcall_cachep,
|
||||
const LONGEST *entry_cfa_sp_offsetp);
|
||||
|
||||
extern struct value *
|
||||
dwarf2_tailcall_prev_register_first (struct frame_info *this_frame,
|
||||
void **tailcall_cachep, int regnum);
|
||||
|
||||
extern const struct frame_unwind dwarf2_tailcall_frame_unwind;
|
||||
|
||||
#endif /* !DWARF2_FRAME_TAILCALL_H */
|
||||
Loading…
Reference in New Issue
Block a user