On Mon, Mar 25, 2019 at 09:42:01PM +0100, Jakub Jelinek wrote:
> BTW, why don't do something like following (dunno if it is valid not to
> define the static data member out of the class unless it would be constexpr
> or inline, but it isn't really ODR used, is it?), because at least looking
> at currently emitted code without --enable-gather-detailed-mem-stats, we
> emit this statistics gathering code everywhere except in the ctors where
> optimizers can clearly see that m_gather_mem_stats is false. But we usually
> don't see that in the destructor or in the methods, especially when they
> aren't inlined. Martin?
Here is an updated version of this patch which I've bootstrapped/regtested
on x86_64-linux and i686-linux (doesn't deal with the issues Jason reported,
that needs a separate patch).
On my --enable-checking=yes,rtl,extra bootstrap on x86_64-linux, the patch
decreases a size of various sections (everything in bytes):
-.hash 155360
+.hash 152528
-.gnu.hash 170088
+.gnu.hash 167256
-.dynsym 538248
+.dynsym 521256
-.dynstr 1032304
+.dynstr 961759
-.gnu.version 44854
+.gnu.version 43438
-.text 24027797
+.text 23951957
-.rodata 8282592
+.rodata 8282432
-.eh_frame_hdr 407036
+.eh_frame_hdr 403700
-.eh_frame 2454384
+.eh_frame 2416392
-.debug_str 6848275
+.debug_str 6847936
I know it isn't that much, but 74KB savings on .text seems to be worth to
me with such a small patch. Ok for trunk?
2019-03-25 Jakub Jelinek <ja...@redhat.com>
* hash-table.h (hash_table::m_gather_mem_stats): If GATHER_STATISTICS
is constant 0, turn into static const data member initialized to false.
(hash_table::hash_table): Only initialize m_gather_mem_stats #if
GATHER_STATISTICS. Add ATTRIBUTE_UNUSED to gather_mem_stats param.
--- gcc/hash-table.h 2019-03-21 22:59:16.501772695 +0100
+++ gcc/hash-table.h 2019-03-25 21:19:32.589325346 +0100
@@ -562,7 +562,11 @@ private:
bool m_ggc;
/* If we should gather memory statistics for the table. */
+#if GATHER_STATISTICS
bool m_gather_mem_stats;
+#else
+ static const bool m_gather_mem_stats = false;
+#endif
};
/* As mem-stats.h heavily utilizes hash maps (hash tables), we have to include
@@ -579,11 +583,15 @@ extern void dump_hash_table_loc_statisti
template<typename Descriptor, bool Lazy,
template<typename Type> class Allocator>
hash_table<Descriptor, Lazy, Allocator>::hash_table (size_t size, bool ggc,
- bool gather_mem_stats,
+ bool gather_mem_stats
+ ATTRIBUTE_UNUSED,
mem_alloc_origin origin
MEM_STAT_DECL) :
m_n_elements (0), m_n_deleted (0), m_searches (0), m_collisions (0),
- m_ggc (ggc), m_gather_mem_stats (gather_mem_stats)
+ m_ggc (ggc)
+#if GATHER_STATISTICS
+ , m_gather_mem_stats (gather_mem_stats)
+#endif
{
unsigned int size_prime_index;
@@ -606,12 +614,15 @@ template<typename Descriptor, bool Lazy,
template<typename Type> class Allocator>
hash_table<Descriptor, Lazy, Allocator>::hash_table (const hash_table &h,
bool ggc,
- bool gather_mem_stats,
+ bool gather_mem_stats
+ ATTRIBUTE_UNUSED,
mem_alloc_origin origin
MEM_STAT_DECL) :
m_n_elements (h.m_n_elements), m_n_deleted (h.m_n_deleted),
- m_searches (0), m_collisions (0), m_ggc (ggc),
- m_gather_mem_stats (gather_mem_stats)
+ m_searches (0), m_collisions (0), m_ggc (ggc)
+#if GATHER_STATISTICS
+ , m_gather_mem_stats (gather_mem_stats)
+#endif
{
size_t size = h.m_size;
Jakub
