From 1a8605a8c79b0c4ebc71f5691e36a1338d407837 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Thu, 20 Oct 2022 13:05:19 -0400 Subject: [PATCH] gdbsupport: add gdb::string_view_hash Add the string_view_hash type, which will be useful to be able to use gdb::string_view as std::unordered_map keys. Use it in gdb/symtab.c, to exercise it. Change-Id: Id69a466ab19a9f6620b5df8a2dd29b5cddd94c00 Approved-By: Andrew Burgess --- gdb/symtab.c | 2 +- gdbsupport/common-utils.h | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/gdb/symtab.c b/gdb/symtab.c index f2b1a14e006..b3445133c8c 100644 --- a/gdb/symtab.c +++ b/gdb/symtab.c @@ -812,7 +812,7 @@ hash_demangled_name_entry (const void *data) const struct demangled_name_entry *e = (const struct demangled_name_entry *) data; - return fast_hash (e->mangled.data (), e->mangled.length ()); + return gdb::string_view_hash () (e->mangled); } /* Equality function for the demangled name hash. */ diff --git a/gdbsupport/common-utils.h b/gdbsupport/common-utils.h index 31ab1a6cec8..97dcb9fa8ce 100644 --- a/gdbsupport/common-utils.h +++ b/gdbsupport/common-utils.h @@ -209,4 +209,21 @@ fast_hash (const void *ptr, size_t len, unsigned int start_value = 0) #endif } +namespace gdb +{ + +/* Hash type for gdb::string_view. + + Even after we switch to C++17 and dump our string_view implementation, we + might want to keep this hash implementation if it's faster than std::hash + for std::string_view. */ + +struct string_view_hash +{ + std::size_t operator() (gdb::string_view view) const + { return fast_hash (view.data (), view.length ()); } +}; + +} /* namespace gdb */ + #endif /* COMMON_COMMON_UTILS_H */ -- 2.30.2