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Allow |CRYPTO_is_NEON_capable| to be known at compile time, if possible.

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If -mfpu=neon is passed then we don't need to worry about checking for
NEON support at run time. This change allows |CRYPTO_is_NEON_capable| to
statically return 1 in this case. This then allows the compiler to
discard generic code in several cases.

Change-Id: I3b229740ea3d5cb0a304f365c400a0996d0c66ef
Reviewed-on: https://boringssl-review.googlesource.com/6523
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
Adam Langley 2015-11-17 15:25:00 -08:00
parent 3ac32b1eda
commit 9e65d487b8
2 changed files with 15 additions and 5 deletions
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2
crypto/cpu-arm.c
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@ -34,7 +34,7 @@ unsigned long getauxval(unsigned long type) __attribute__((weak));
extern uint32_t OPENSSL_armcap_P;
char CRYPTO_is_NEON_capable(void) {
char CRYPTO_is_NEON_capable_at_runtime(void) {
return (OPENSSL_armcap_P & ARMV7_NEON) != 0;
}

18
include/openssl/cpu.h
View File

@ -102,10 +102,20 @@ extern uint32_t OPENSSL_ia32cap_P[4];
#if !defined(OPENSSL_STATIC_ARMCAP)
/* CRYPTO_is_NEON_capable returns true if the current CPU has a NEON unit. Note
* that |OPENSSL_armcap_P| also exists and contains the same information in a
* form that's easier for assembly to use. */
OPENSSL_EXPORT char CRYPTO_is_NEON_capable(void);
/* CRYPTO_is_NEON_capable_at_runtime returns true if the current CPU has a NEON
* unit. Note that |OPENSSL_armcap_P| also exists and contains the same
* information in a form that's easier for assembly to use. */
OPENSSL_EXPORT char CRYPTO_is_NEON_capable_at_runtime(void);
/* CRYPTO_is_NEON_capable returns true if the current CPU has a NEON unit. If
* this is known statically then it returns one immediately. */
static inline int CRYPTO_is_NEON_capable(void) {
#if defined(__ARM_NEON__)
return 1;
#else
return CRYPTO_is_NEON_capable_at_runtime();
#endif
}
/* CRYPTO_set_NEON_capable sets the return value of |CRYPTO_is_NEON_capable|.
* By default, unless the code was compiled with |-mfpu=neon|, NEON is assumed