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gdb/gdb-symtab-resolve-deferred-entries-inter-shard-case.patch

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From e2d7097cf236c9ea6959785754d067833fc302af Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Tue, 22 Aug 2023 14:24:42 +0200
Subject: [PATCH 05/13] [gdb/symtab] Resolve deferred entries, inter-shard case
Generically solve the case of inter-CU dependencies, including inter-shard
dependencies:
- mark deferred entries in new data structure m_deferred,
- return &parent_map::deferred in find_parent for deferred entries,
- defer all intra-CU dependencies that depend on deferred entries,
- defer all inter-CU dependencies (note that two subsequent patches implement
optimizations to deal with this more optimally),
- move m_die_range_map and m_deferred_dies to cooked_index_shard, and
- move handle_deferred_dies to the cooked_index, where it is called in the
constructor, and update it to handle the intra-shard case.
Handling units from the .debug_info section alongside units from the
.debug_types section requires us to extend form_addr to take is_debug_types
into account.
Tested on x86_64-linux.
PR symtab/30846
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30846
---
gdb/dwarf2/cooked-index.c | 77 +++++++++++++++++++++++
gdb/dwarf2/cooked-index.h | 105 ++++++++++++++++++++++++++++++-
gdb/dwarf2/read.c | 128 ++++++++++++++++++++++----------------
3 files changed, 254 insertions(+), 56 deletions(-)
diff --git a/gdb/dwarf2/cooked-index.c b/gdb/dwarf2/cooked-index.c
index 58ea541a5c9..3231d25db5a 100644
--- a/gdb/dwarf2/cooked-index.c
+++ b/gdb/dwarf2/cooked-index.c
@@ -228,6 +228,12 @@ cooked_index_entry::write_scope (struct obstack *storage,
/* See cooked-index.h. */
+cooked_index_entry parent_map::deferred((sect_offset)0, (dwarf_tag)0,
+ (cooked_index_flag)0, nullptr,
+ nullptr, nullptr);
+
+/* See cooked-index.h. */
+
const cooked_index_entry *
cooked_index_shard::add (sect_offset die_offset, enum dwarf_tag tag,
cooked_index_flag flags, const char *name,
@@ -446,6 +452,8 @@ cooked_index_shard::wait (bool allow_quit) const
cooked_index::cooked_index (vec_type &&vec)
: m_vector (std::move (vec))
{
+ handle_deferred_entries ();
+
for (auto &idx : m_vector)
idx->finalize ();
@@ -649,6 +657,75 @@ cooked_index::maybe_write_index (dwarf2_per_bfd *per_bfd,
global_index_cache.store (per_bfd, ctx);
}
+/* See cooked-index.h. */
+
+const cooked_index_entry *
+cooked_index_shard::resolve_deferred_entry
+ (const deferred_entry &de, const cooked_index_entry *parent_entry)
+{
+ reset_parent_deferred (parent_map::form_addr (de.die_offset, de.per_cu_2->is_dwz,
+ de.per_cu_2->is_debug_types));
+ return add (de.die_offset, de.tag, de.flags, de.name,
+ parent_entry, de.per_cu);
+}
+
+/* See cooked-index.h. */
+
+const cooked_index_entry *
+cooked_index::find_parent_deferred_entry
+ (const cooked_index_shard::deferred_entry &entry) const
+{
+ const cooked_index_entry *parent_entry = nullptr;
+ for (auto &parent_map_shard : m_vector)
+ {
+ auto res = parent_map_shard->find_parent (entry.spec_offset);
+ if (res != nullptr)
+ {
+ parent_entry = res;
+ break;
+ }
+ }
+
+ return parent_entry;
+}
+
+/* See cooked-index.h. */
+
+void
+cooked_index::handle_deferred_entries ()
+{
+ bool changed;
+ bool deferred;
+ do
+ {
+ deferred = false;
+ changed = false;
+ for (auto &shard : m_vector)
+ for (auto it = shard->m_deferred_entries->begin ();
+ it != shard->m_deferred_entries->end (); )
+ {
+ const cooked_index_entry *parent_entry
+ = find_parent_deferred_entry (*it);
+ if (parent_entry == &parent_map::deferred)
+ {
+ deferred = true;
+ it++;
+ continue;
+ }
+ shard->resolve_deferred_entry (*it, parent_entry);
+ it = shard->m_deferred_entries->erase (it);
+ changed = true;
+ }
+ }
+ while (changed && deferred);
+
+ for (auto &shard : m_vector)
+ {
+ shard->m_die_range_map.reset (nullptr);
+ shard->m_deferred_entries.reset (nullptr);
+ }
+}
+
/* Wait for all the index cache entries to be written before gdb
exits. */
static void
diff --git a/gdb/dwarf2/cooked-index.h b/gdb/dwarf2/cooked-index.h
index 79fbfe88c03..66424c37f7c 100644
--- a/gdb/dwarf2/cooked-index.h
+++ b/gdb/dwarf2/cooked-index.h
@@ -34,6 +34,7 @@
#include "dwarf2/mapped-index.h"
#include "dwarf2/tag.h"
#include "gdbsupport/range-chain.h"
+#include <unordered_set>
struct dwarf2_per_cu_data;
struct dwarf2_per_bfd;
@@ -242,19 +243,29 @@ struct cooked_index_entry : public allocate_on_obstack
class parent_map
{
public:
+ /* A dummy cooked_index_entry to mark that computing the parent has been
+ deferred. */
+ static cooked_index_entry deferred;
+
/* A helper function to turn a section offset into an address that
can be used in a parent_map. */
- static CORE_ADDR form_addr (sect_offset offset, bool is_dwz)
+ static CORE_ADDR form_addr (sect_offset offset, bool is_dwz,
+ bool is_debug_types)
{
CORE_ADDR value = to_underlying (offset);
if (is_dwz)
value |= ((CORE_ADDR) 1) << (8 * sizeof (CORE_ADDR) - 1);
+ if (is_debug_types)
+ value |= ((CORE_ADDR) 1) << (8 * sizeof (CORE_ADDR) - 2);
return value;
}
/* Find the parent of DIE LOOKUP. */
const cooked_index_entry *find_parent (CORE_ADDR lookup) const
{
+ if (m_deferred.find (lookup) != m_deferred.end ())
+ return &parent_map::deferred;
+
const void *obj = m_parent_map.find (lookup);
return static_cast<const cooked_index_entry *> (obj);
}
@@ -265,12 +276,28 @@ class parent_map
{
/* Calling set_empty with nullptr is currently not allowed. */
if (parent_entry != nullptr)
- m_parent_map.set_empty (start, end, (void *)parent_entry);
+ {
+ gdb_assert (parent_entry != &parent_map::deferred);
+ m_parent_map.set_empty (start, end, (void *)parent_entry);
+ }
+ }
+
+ void set_parent_deferred (CORE_ADDR addr)
+ {
+ m_deferred.emplace (addr);
+ }
+
+ void reset_parent_deferred (CORE_ADDR addr)
+ {
+ m_deferred.erase (addr);
}
private:
/* An addrmap that maps from section offsets to cooked_index_entry *. */
addrmap_mutable m_parent_map;
+
+ /* DIEs that are deffered. */
+ std::unordered_set<CORE_ADDR> m_deferred;
};
class cooked_index;
@@ -285,7 +312,12 @@ class cooked_index;
class cooked_index_shard
{
public:
- cooked_index_shard () = default;
+ cooked_index_shard ()
+ {
+ m_die_range_map.reset (new parent_map);
+ m_deferred_entries.reset (new std::vector<deferred_entry>);
+ }
+
DISABLE_COPY_AND_ASSIGN (cooked_index_shard);
/* Create a new cooked_index_entry and register it with this object.
@@ -329,6 +361,52 @@ class cooked_index_shard
for completion, will be returned. */
range find (const std::string &name, bool completing) const;
+ /* Find the parent of DIE LOOKUP. */
+ const cooked_index_entry *
+ find_parent (CORE_ADDR lookup) const
+ {
+ return m_die_range_map->find_parent (lookup);
+ }
+
+ /* Set the parent of DIES in range [START, END] to PARENT_ENTRY. */
+ void set_parent (CORE_ADDR start, CORE_ADDR end,
+ const cooked_index_entry *parent_entry)
+ {
+ m_die_range_map->set_parent (start, end, parent_entry);
+ }
+
+ void set_parent_deferred (CORE_ADDR addr)
+ {
+ m_die_range_map->set_parent_deferred (addr);
+ }
+
+ void reset_parent_deferred (CORE_ADDR addr)
+ {
+ m_die_range_map->reset_parent_deferred (addr);
+ }
+
+ /* A single deferred entry. See m_deferred_entries. */
+ struct deferred_entry
+ {
+ sect_offset die_offset;
+ const char *name;
+ CORE_ADDR spec_offset;
+ dwarf_tag tag;
+ cooked_index_flag flags;
+ dwarf2_per_cu_data *per_cu;
+ dwarf2_per_cu_data *per_cu_2;
+ };
+
+ /* Defer creating a cooked_index_entry corresponding to DEFERRED. */
+ void defer_entry (deferred_entry de)
+ {
+ m_deferred_entries->push_back (de);
+ }
+
+ /* Variant of add that takes a deferred_entry as parameter. */
+ const cooked_index_entry *resolve_deferred_entry
+ (const deferred_entry &entry, const cooked_index_entry *parent_entry);
+
private:
/* Return the entry that is believed to represent the program's
@@ -386,6 +464,20 @@ class cooked_index_shard
that the 'get' method is never called on this future, only
'wait'. */
gdb::future<void> m_future;
+
+ /* An addrmap that maps from section offsets (see the form_addr
+ method) to newly-created entries. See m_deferred_entries to
+ understand this. */
+ std::unique_ptr<parent_map> m_die_range_map;
+
+ /* The generated DWARF can sometimes have the declaration for a
+ method in a class (or perhaps namespace) scope, with the
+ definition appearing outside this scope... just one of the many
+ bad things about DWARF. In order to handle this situation, we
+ defer certain entries until the end of scanning, at which point
+ we'll know the containing context of all the DIEs that we might
+ have scanned. This vector stores these deferred entries. */
+ std::unique_ptr<std::vector<deferred_entry>> m_deferred_entries;
};
/* The main index of DIEs. The parallel DIE indexers create
@@ -469,6 +561,13 @@ class cooked_index : public dwarf_scanner_base
private:
+ /* Find the parent corresponding to deferred entry ENTRY. */
+ const cooked_index_entry *find_parent_deferred_entry
+ (const cooked_index_shard::deferred_entry &entry) const;
+
+ /* Create cooked_index_entries for the deferred entries. */
+ void handle_deferred_entries ();
+
/* Maybe write the index to the index cache. */
void maybe_write_index (dwarf2_per_bfd *per_bfd,
const index_cache_store_context &);
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index afdf9e870a8..5b7c0969ed7 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -4672,6 +4672,31 @@ class cooked_index_storage
return &m_addrmap;
}
+ /* Find the parent of DIE LOOKUP. */
+ const cooked_index_entry *find_parent (CORE_ADDR lookup)
+ {
+ return m_index->find_parent (lookup);
+ }
+
+ /* Set the parent of DIES in range [START, END] to PARENT_ENTRY. */
+ void set_parent (CORE_ADDR start, CORE_ADDR end,
+ const cooked_index_entry *parent_entry)
+ {
+ m_index->set_parent (start, end, parent_entry);
+ }
+
+ /* Set the parent of DIE at ADDR as deferred. */
+ void set_parent_deferred (CORE_ADDR addr)
+ {
+ m_index->set_parent_deferred (addr);
+ }
+
+ /* Defer creating a cooked_index_entry corresponding to deferred_entry DE. */
+ void defer_entry (cooked_index_shard::deferred_entry de)
+ {
+ m_index->defer_entry (de);
+ }
+
private:
/* Hash function for a cutu_reader. */
@@ -4794,59 +4819,26 @@ class cooked_indexer
/* Find the parent of DIE LOOKUP. */
const cooked_index_entry *find_parent (CORE_ADDR lookup) const
{
- return m_die_range_map.find_parent (lookup);
+ return m_index_storage->find_parent (lookup);
}
/* Set the parent of DIES in range [START, END] to PARENT_ENTRY. */
void set_parent (CORE_ADDR start, CORE_ADDR end,
const cooked_index_entry *parent_entry)
{
- m_die_range_map.set_parent (start, end, parent_entry);
+ m_index_storage->set_parent (start, end, parent_entry);
}
- /* A single deferred entry. */
- struct deferred_entry
- {
- sect_offset die_offset;
- const char *name;
- CORE_ADDR spec_offset;
- dwarf_tag tag;
- cooked_index_flag flags;
- };
-
- /* The generated DWARF can sometimes have the declaration for a
- method in a class (or perhaps namespace) scope, with the
- definition appearing outside this scope... just one of the many
- bad things about DWARF. In order to handle this situation, we
- defer certain entries until the end of scanning, at which point
- we'll know the containing context of all the DIEs that we might
- have scanned. This vector stores these deferred entries. */
- std::vector<deferred_entry> m_deferred_entries;
-
- /* Defer creating a cooked_index_entry corresponding to deferred_entry DE. */
- void defer_entry (const deferred_entry &de)
+ /* Set the parent of DIE at ADDR as deferred. */
+ void set_parent_deferred (CORE_ADDR addr)
{
- m_deferred_entries.push_back (de);
+ m_index_storage->set_parent_deferred (addr);
}
- /* Create a cooked_index_entry corresponding to deferred_entry DE with
- parent PARENT_ENTRY. */
- const cooked_index_entry *resolve_deferred_entry
- (const deferred_entry &de, const cooked_index_entry *parent_entry)
- {
- return m_index_storage->add (de.die_offset, de.tag, de.flags, de.name,
- parent_entry, m_per_cu);
- }
-
- /* Create cooked_index_entries for the deferred entries. */
- void handle_deferred_entries ()
+ /* Defer creating a cooked_index_entry corresponding to deferred_entry DE. */
+ void defer_entry (const cooked_index_shard::deferred_entry &de)
{
- for (const auto &entry : m_deferred_entries)
- {
- const cooked_index_entry *parent_entry
- = find_parent (entry.spec_offset);
- resolve_deferred_entry (entry, parent_entry);
- }
+ m_index_storage->defer_entry (de);
}
};
@@ -16441,13 +16433,36 @@ cooked_indexer::scan_attributes (dwarf2_per_cu_data *scanning_per_cu,
if (*parent_entry == nullptr)
{
+ gdb_assert (reader->cu->per_cu->is_debug_types
+ == new_reader->cu->per_cu->is_debug_types);
CORE_ADDR addr
- = parent_map::form_addr (origin_offset, origin_is_dwz);
- if (new_reader->cu == reader->cu
- && new_info_ptr > watermark_ptr)
- *maybe_defer = addr;
+ = parent_map::form_addr (origin_offset, origin_is_dwz,
+ reader->cu->per_cu->is_debug_types);
+ if (new_reader->cu == reader->cu)
+ {
+ /* Intra-CU case. */
+ if (new_info_ptr > watermark_ptr)
+ {
+ /* Defer because origin is not read yet. */
+ *maybe_defer = addr;
+ }
+ else
+ {
+ auto tmp = find_parent (addr);
+ if (tmp == &parent_map::deferred)
+ {
+ /* Defer because origin is deferred. */
+ *maybe_defer = addr;
+ }
+ else
+ *parent_entry = tmp;
+ }
+ }
else
- *parent_entry = find_parent (addr);
+ {
+ /* Inter-CU case. */
+ *maybe_defer = addr;
+ }
}
unsigned int bytes_read;
@@ -16567,10 +16582,12 @@ cooked_indexer::recurse (cutu_reader *reader,
limit the range to the children of parent_entry. */
CORE_ADDR start
= parent_map::form_addr (parent_entry->die_offset + 1,
- reader->cu->per_cu->is_dwz);
+ reader->cu->per_cu->is_dwz,
+ reader->cu->per_cu->is_debug_types);
CORE_ADDR end
= parent_map::form_addr (sect_offset (info_ptr - 1 - reader->buffer),
- reader->cu->per_cu->is_dwz);
+ reader->cu->per_cu->is_dwz,
+ reader->cu->per_cu->is_debug_types);
set_parent (start, end, parent_entry);
}
@@ -16637,9 +16654,16 @@ cooked_indexer::index_dies (cutu_reader *reader,
if (name != nullptr)
{
if (defer != 0)
- defer_entry ({
- this_die, name, defer, abbrev->tag, flags
- });
+ {
+ CORE_ADDR addr
+ = parent_map::form_addr (this_die, reader->cu->per_cu->is_dwz,
+ reader->cu->per_cu->is_debug_types);
+ set_parent_deferred (addr);
+ defer_entry ({
+ this_die, name, defer, abbrev->tag, flags, m_per_cu,
+ reader->cu->per_cu
+ });
+ }
else
this_entry = m_index_storage->add (this_die, abbrev->tag, flags,
name, this_parent_entry,
@@ -16741,8 +16765,6 @@ cooked_indexer::make_index (cutu_reader *reader)
if (!reader->comp_unit_die->has_children)
return;
index_dies (reader, reader->info_ptr, nullptr, false);
-
- handle_deferred_entries ();
}
/* An implementation of quick_symbol_functions for the cooked DWARF
--
2.35.3
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