commit: dd36b398d1d8497ebe47766a1a11286d135ce102
parent 5f61b01da9f50968b18af900f9f9b3f024b314a1
Author: Michael Forney <mforney@mforney.org>
Date: Fri, 7 Jun 2019 14:44:11 -0700
libxkbcommon: Avoid __builtin_popcount
Diffstat:
3 files changed, 89 insertions(+), 2 deletions(-)
diff --git a/pkg/libxkbcommon/config.h b/pkg/libxkbcommon/config.h
@@ -8,6 +8,5 @@
#define HAVE_MMAP 1
#define HAVE_POSIX_FALLOCATE 1
#define HAVE___BUILTIN_EXPECT 1
-#define HAVE___BUILTIN_POPCOUNT 1
#define XLOCALEDIR "/share/xlocale"
#define _GNU_SOURCE 1
diff --git a/pkg/libxkbcommon/patch/0001-Use-bitwise-test-for-power-of-2-instead-of-popcount.patch b/pkg/libxkbcommon/patch/0001-Use-bitwise-test-for-power-of-2-instead-of-popcount.patch
@@ -0,0 +1,88 @@
+From a0c5a34683049641590bdda2ae11149e5265fd91 Mon Sep 17 00:00:00 2001
+From: Michael Forney <mforney@mforney.org>
+Date: Tue, 4 Jun 2019 14:01:02 -0700
+Subject: [PATCH] Use bitwise test for power-of-2 instead of popcount
+
+We don't need to determine the total number of bits set to determine if
+at most one is set.
+
+Additionally, on x86_64 without any -march=* flag, __builtin_popcount
+will get compiled to a function call to the compiler runtime (on gcc),
+or a long sequence of bit operations (on clang).
+
+Signed-off-by: Michael Forney <mforney@mforney.org>
+---
+ configure.ac | 1 -
+ meson.build | 3 ---
+ src/state.c | 3 ++-
+ src/utils.h | 14 --------------
+ 4 files changed, 2 insertions(+), 19 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index 957da59..cd958b0 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -77,7 +77,6 @@ AS_IF([test "x$ac_cv_func_secure_getenv" = xno -a \
+ ])
+
+ AX_GCC_BUILTIN(__builtin_expect)
+-AX_GCC_BUILTIN(__builtin_popcount)
+
+ # Some tests use Linux-specific headers
+ AC_CHECK_HEADER([linux/input.h])
+diff --git a/meson.build b/meson.build
+index 6f0b596..61ba681 100644
+--- a/meson.build
++++ b/meson.build
+@@ -76,9 +76,6 @@ endif
+ if cc.links('int main(){if(__builtin_expect(1<0,0)){}}', name: '__builtin_expect')
+ configh_data.set('HAVE___BUILTIN_EXPECT', 1)
+ endif
+-if cc.links('int main(){__builtin_popcount(1);}', name: '__builtin_popcount')
+- configh_data.set('HAVE___BUILTIN_POPCOUNT', 1)
+-endif
+ if cc.has_header_symbol('unistd.h', 'eaccess', prefix: '#define _GNU_SOURCE')
+ configh_data.set('HAVE_EACCESS', 1)
+ endif
+diff --git a/src/state.c b/src/state.c
+index 16a4caa..dc1c651 100644
+--- a/src/state.c
++++ b/src/state.c
+@@ -1373,7 +1373,8 @@ key_get_consumed(struct xkb_state *state, const struct xkb_key *key,
+ if (XkbLevelsSameSyms(level, no_mods_level))
+ continue;
+
+- if (entry == matching_entry || my_popcount(entry->mods.mask) == 1)
++ if (entry == matching_entry ||
++ (entry->mods.mask & (entry->mods.mask - 1)) == 0)
+ consumed |= entry->mods.mask & ~entry->preserve.mask;
+ }
+ break;
+diff --git a/src/utils.h b/src/utils.h
+index cb98e8e..060f071 100644
+--- a/src/utils.h
++++ b/src/utils.h
+@@ -186,20 +186,6 @@ msb_pos(uint32_t mask)
+ return pos;
+ }
+
+-// Avoid conflict with other popcount()s.
+-static inline int
+-my_popcount(uint32_t x)
+-{
+- int count;
+-#if defined(HAVE___BUILTIN_POPCOUNT)
+- count = __builtin_popcount(x);
+-#else
+- for (count = 0; x; count++)
+- x &= x - 1;
+-#endif
+- return count;
+-}
+-
+ bool
+ map_file(FILE *file, char **string_out, size_t *size_out);
+
+--
+2.20.1
+
diff --git a/pkg/libxkbcommon/ver b/pkg/libxkbcommon/ver
@@ -1 +1 @@
-0.8.4 r0
+0.8.4 r1
