From: Tom Tromey <tom@tromey.com>
To: gdb-patches@sourceware.org
Cc: Tom Tromey <tom@tromey.com>, Pedro Alves <pedro@palves.net>
Subject: [PATCH v2 4/8] Use try_emplace in index-write.c
Date: Tue, 21 Nov 2023 08:27:31 -0700 [thread overview]
Message-ID: <20231121152817.31859-5-tom@tromey.com> (raw)
In-Reply-To: <20231121152817.31859-1-tom@tromey.com>
index-write.c has a comment indicating that C++17's try_emplace could
be used. This patch makes the change.
Approved-By: Pedro Alves <pedro@palves.net>
---
gdb/dwarf2/index-write.c | 25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)
diff --git a/gdb/dwarf2/index-write.c b/gdb/dwarf2/index-write.c
index d1b10a28823..3aafc1aab74 100644
--- a/gdb/dwarf2/index-write.c
+++ b/gdb/dwarf2/index-write.c
@@ -385,24 +385,17 @@ write_hash_table (mapped_symtab *symtab, data_buf &output, data_buf &cpool)
continue;
gdb_assert (entry.index_offset == 0);
- /* Finding before inserting is faster than always trying to
- insert, because inserting always allocates a node, does the
- lookup, and then destroys the new node if another node
- already had the same key. C++17 try_emplace will avoid
- this. */
- const auto found
- = symbol_hash_table.find (entry.cu_indices);
- if (found != symbol_hash_table.end ())
+ auto [iter, inserted]
+ = symbol_hash_table.try_emplace (entry.cu_indices,
+ cpool.size ());
+ entry.index_offset = iter->second;
+ if (inserted)
{
- entry.index_offset = found->second;
- continue;
+ /* Newly inserted. */
+ cpool.append_offset (entry.cu_indices.size ());
+ for (const auto index : entry.cu_indices)
+ cpool.append_offset (index);
}
-
- symbol_hash_table.emplace (entry.cu_indices, cpool.size ());
- entry.index_offset = cpool.size ();
- cpool.append_offset (entry.cu_indices.size ());
- for (const auto index : entry.cu_indices)
- cpool.append_offset (index);
}
}
--
2.41.0
next prev parent reply other threads:[~2023-11-21 15:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-21 15:27 Tom Tromey
2023-11-21 15:27 ` [PATCH v2 1/8] Use C++17 [[fallthrough]] attribute Tom Tromey
2023-11-30 18:03 ` Simon Marchi
2023-11-30 19:13 ` Tom Tromey
2023-11-30 21:08 ` Simon Marchi
2023-12-01 3:55 ` Tom Tromey
2023-12-01 4:17 ` Simon Marchi
2023-11-21 15:27 ` [PATCH v2 2/8] Switch to -Wimplicit-fallthrough=5 Tom Tromey
2023-11-21 15:27 ` [PATCH v2 3/8] Enable some C++14 code in array-view.h Tom Tromey
2023-11-21 15:27 ` Tom Tromey [this message]
2023-11-21 15:27 ` [PATCH v2 5/8] Rely on C++17 <new> in new-op.cc Tom Tromey
2023-11-21 15:27 ` [PATCH v2 6/8] Rely on copy elision in scope-exit.h Tom Tromey
2023-11-21 15:27 ` [PATCH v2 7/8] Use C++17 void_t Tom Tromey
2023-11-21 15:27 ` [PATCH v2 8/8] Remove gdb_static_assert Tom Tromey
2023-11-29 23:28 ` (unknown) Tom Tromey
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