From 79f1f7a4f123765cf07be92ae894d882c5845191 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Sun, 9 Aug 2020 10:58:40 -0700 Subject: [PATCH] Autodetect __int128 availability on the C side Instead of supporting configuration of the field and scalar size independently, both are now controlled by the availability of a 64x64->128 bit multiplication (currently only through __int128). This is autodetected from the C code through __SIZEOF_INT128__, but can be overridden using configure's --with-test-override-wide-multiply, or by defining USE_FORCE_WIDEMUL_{INT64,INT128} manually. --- .travis.yml | 20 +++---- build-aux/m4/bitcoin_secp.m4 | 5 -- configure.ac | 102 ++++++----------------------------- contrib/travis.sh | 2 +- src/basic-config.h | 10 ++-- src/field.h | 16 +++--- src/field_impl.h | 8 +-- src/scalar.h | 7 +-- src/scalar_impl.h | 6 +-- src/util.h | 27 +++++++--- 10 files changed, 69 insertions(+), 134 deletions(-) diff --git a/.travis.yml b/.travis.yml index 491da6c..81d1ba8 100644 --- a/.travis.yml +++ b/.travis.yml @@ -17,17 +17,17 @@ compiler: - gcc env: global: - - FIELD=auto BIGNUM=auto SCALAR=auto ENDOMORPHISM=no STATICPRECOMPUTATION=yes ECMULTGENPRECISION=auto ASM=no BUILD=check EXTRAFLAGS= HOST= ECDH=no RECOVERY=no EXPERIMENTAL=no CTIMETEST=yes BENCH=yes ITERS=2 + - WIDEMUL=auto BIGNUM=auto ENDOMORPHISM=no STATICPRECOMPUTATION=yes ECMULTGENPRECISION=auto ASM=no BUILD=check EXTRAFLAGS= HOST= ECDH=no RECOVERY=no EXPERIMENTAL=no CTIMETEST=yes BENCH=yes ITERS=2 matrix: - - SCALAR=32bit RECOVERY=yes - - SCALAR=32bit FIELD=32bit ECDH=yes EXPERIMENTAL=yes - - SCALAR=64bit - - FIELD=64bit RECOVERY=yes - - FIELD=64bit ENDOMORPHISM=yes - - FIELD=64bit ENDOMORPHISM=yes ECDH=yes EXPERIMENTAL=yes - - FIELD=64bit ASM=x86_64 - - FIELD=64bit ENDOMORPHISM=yes ASM=x86_64 - - FIELD=32bit ENDOMORPHISM=yes + - WIDEMUL=int64 RECOVERY=yes + - WIDEMUL=int64 ECDH=yes EXPERIMENTAL=yes + - WIDEMUL=int64 ENDOMORPHISM=yes + - WIDEMUL=int128 + - WIDEMUL=int128 RECOVERY=yes + - WIDEMUL=int128 ENDOMORPHISM=yes + - WIDEMUL=int128 ENDOMORPHISM=yes ECDH=yes EXPERIMENTAL=yes + - WIDEMUL=int128 ASM=x86_64 + - WIDEMUL=int128 ENDOMORPHISM=yes ASM=x86_64 - BIGNUM=no - BIGNUM=no ENDOMORPHISM=yes RECOVERY=yes EXPERIMENTAL=yes - BIGNUM=no STATICPRECOMPUTATION=no diff --git a/build-aux/m4/bitcoin_secp.m4 b/build-aux/m4/bitcoin_secp.m4 index 1b2b71e..57595f4 100644 --- a/build-aux/m4/bitcoin_secp.m4 +++ b/build-aux/m4/bitcoin_secp.m4 @@ -1,8 +1,3 @@ -dnl libsecp25k1 helper checks -AC_DEFUN([SECP_INT128_CHECK],[ -has_int128=$ac_cv_type___int128 -]) - dnl escape "$0x" below using the m4 quadrigaph @S|@, and escape it again with a \ for the shell. AC_DEFUN([SECP_64BIT_ASM_CHECK],[ AC_MSG_CHECKING(for x86_64 assembly availability) diff --git a/configure.ac b/configure.ac index 6021b76..1c01c4f 100644 --- a/configure.ac +++ b/configure.ac @@ -141,15 +141,13 @@ AC_ARG_ENABLE(external_default_callbacks, [use_external_default_callbacks=$enableval], [use_external_default_callbacks=no]) -AC_ARG_WITH([field], [AS_HELP_STRING([--with-field=64bit|32bit|auto], -[finite field implementation to use [default=auto]])],[req_field=$withval], [req_field=auto]) +dnl Test-only override of the (autodetected by the C code) "widemul" setting. +dnl Legal values are int64 (for [u]int64_t), int128 (for [unsigned] __int128), and auto (the default). +AC_ARG_WITH([test-override-wide-multiply], [] ,[set_widemul=$withval], [set_widemul=auto]) AC_ARG_WITH([bignum], [AS_HELP_STRING([--with-bignum=gmp|no|auto], [bignum implementation to use [default=auto]])],[req_bignum=$withval], [req_bignum=auto]) -AC_ARG_WITH([scalar], [AS_HELP_STRING([--with-scalar=64bit|32bit|auto], -[scalar implementation to use [default=auto]])],[req_scalar=$withval], [req_scalar=auto]) - AC_ARG_WITH([asm], [AS_HELP_STRING([--with-asm=x86_64|arm|no|auto], [assembly optimizations to use (experimental: arm) [default=auto]])],[req_asm=$withval], [req_asm=auto]) @@ -170,8 +168,6 @@ AC_ARG_WITH([ecmult-gen-precision], [AS_HELP_STRING([--with-ecmult-gen-precision )], [req_ecmult_gen_precision=$withval], [req_ecmult_gen_precision=auto]) -AC_CHECK_TYPES([__int128]) - AC_CHECK_HEADER([valgrind/memcheck.h], [enable_valgrind=yes], [enable_valgrind=no], []) AM_CONDITIONAL([VALGRIND_ENABLED],[test "$enable_valgrind" = "yes"]) @@ -265,63 +261,6 @@ else esac fi -if test x"$req_field" = x"auto"; then - if test x"set_asm" = x"x86_64"; then - set_field=64bit - fi - if test x"$set_field" = x; then - SECP_INT128_CHECK - if test x"$has_int128" = x"yes"; then - set_field=64bit - fi - fi - if test x"$set_field" = x; then - set_field=32bit - fi -else - set_field=$req_field - case $set_field in - 64bit) - if test x"$set_asm" != x"x86_64"; then - SECP_INT128_CHECK - if test x"$has_int128" != x"yes"; then - AC_MSG_ERROR([64bit field explicitly requested but neither __int128 support or x86_64 assembly available]) - fi - fi - ;; - 32bit) - ;; - *) - AC_MSG_ERROR([invalid field implementation selection]) - ;; - esac -fi - -if test x"$req_scalar" = x"auto"; then - SECP_INT128_CHECK - if test x"$has_int128" = x"yes"; then - set_scalar=64bit - fi - if test x"$set_scalar" = x; then - set_scalar=32bit - fi -else - set_scalar=$req_scalar - case $set_scalar in - 64bit) - SECP_INT128_CHECK - if test x"$has_int128" != x"yes"; then - AC_MSG_ERROR([64bit scalar explicitly requested but __int128 support not available]) - fi - ;; - 32bit) - ;; - *) - AC_MSG_ERROR([invalid scalar implementation selected]) - ;; - esac -fi - if test x"$req_bignum" = x"auto"; then SECP_GMP_CHECK if test x"$has_gmp" = x"yes"; then @@ -365,16 +304,18 @@ no) ;; esac -# select field implementation -case $set_field in -64bit) - AC_DEFINE(USE_FIELD_5X52, 1, [Define this symbol to use the FIELD_5X52 implementation]) +# select wide multiplication implementation +case $set_widemul in +int128) + AC_DEFINE(USE_FORCE_WIDEMUL_INT128, 1, [Define this symbol to force the use of the (unsigned) __int128 based wide multiplication implementation]) ;; -32bit) - AC_DEFINE(USE_FIELD_10X26, 1, [Define this symbol to use the FIELD_10X26 implementation]) +int64) + AC_DEFINE(USE_FORCE_WIDEMUL_INT64, 1, [Define this symbol to force the use of the (u)int64_t based wide multiplication implementation]) + ;; +auto) ;; *) - AC_MSG_ERROR([invalid field implementation]) + AC_MSG_ERROR([invalid wide multiplication implementation]) ;; esac @@ -396,19 +337,6 @@ no) ;; esac -#select scalar implementation -case $set_scalar in -64bit) - AC_DEFINE(USE_SCALAR_4X64, 1, [Define this symbol to use the 4x64 scalar implementation]) - ;; -32bit) - AC_DEFINE(USE_SCALAR_8X32, 1, [Define this symbol to use the 8x32 scalar implementation]) - ;; -*) - AC_MSG_ERROR([invalid scalar implementation]) - ;; -esac - #set ecmult window size if test x"$req_ecmult_window" = x"auto"; then set_ecmult_window=15 @@ -553,10 +481,12 @@ echo " module recovery = $enable_module_recovery" echo echo " asm = $set_asm" echo " bignum = $set_bignum" -echo " field = $set_field" -echo " scalar = $set_scalar" echo " ecmult window size = $set_ecmult_window" echo " ecmult gen prec. bits = $set_ecmult_gen_precision" +dnl Hide test-only options unless they're used. +if test x"$set_widemul" != xauto; then +echo " wide multiplication = $set_widemul" +fi echo echo " valgrind = $enable_valgrind" echo " CC = $CC" diff --git a/contrib/travis.sh b/contrib/travis.sh index 2c0cbcd..2023d0b 100755 --- a/contrib/travis.sh +++ b/contrib/travis.sh @@ -14,7 +14,7 @@ fi ./configure \ --enable-experimental="$EXPERIMENTAL" --enable-endomorphism="$ENDOMORPHISM" \ - --with-field="$FIELD" --with-bignum="$BIGNUM" --with-asm="$ASM" --with-scalar="$SCALAR" \ + --with-test-override-wide-multiply="$WIDEMUL" --with-bignum="$BIGNUM" --with-asm="$ASM" \ --enable-ecmult-static-precomputation="$STATICPRECOMPUTATION" --with-ecmult-gen-precision="$ECMULTGENPRECISION" \ --enable-module-ecdh="$ECDH" --enable-module-recovery="$RECOVERY" \ --host="$HOST" $EXTRAFLAGS diff --git a/src/basic-config.h b/src/basic-config.h index b5ccd83..83dbe6f 100644 --- a/src/basic-config.h +++ b/src/basic-config.h @@ -14,24 +14,20 @@ #undef USE_ENDOMORPHISM #undef USE_EXTERNAL_ASM #undef USE_EXTERNAL_DEFAULT_CALLBACKS -#undef USE_FIELD_10X26 -#undef USE_FIELD_5X52 #undef USE_FIELD_INV_BUILTIN #undef USE_FIELD_INV_NUM #undef USE_NUM_GMP #undef USE_NUM_NONE -#undef USE_SCALAR_4X64 -#undef USE_SCALAR_8X32 #undef USE_SCALAR_INV_BUILTIN #undef USE_SCALAR_INV_NUM +#undef USE_FORCE_WIDEMUL_INT64 +#undef USE_FORCE_WIDEMUL_INT128 #undef ECMULT_WINDOW_SIZE -#undef HAVE___INT128 /* used in util.h */ #define USE_NUM_NONE 1 #define USE_FIELD_INV_BUILTIN 1 #define USE_SCALAR_INV_BUILTIN 1 -#define USE_FIELD_10X26 1 -#define USE_SCALAR_8X32 1 +#define USE_WIDEMUL_64 1 #define ECMULT_WINDOW_SIZE 15 #endif /* USE_BASIC_CONFIG */ diff --git a/src/field.h b/src/field.h index 7993a1f..aca1fb7 100644 --- a/src/field.h +++ b/src/field.h @@ -22,16 +22,16 @@ #include "libsecp256k1-config.h" #endif -#if defined(USE_FIELD_10X26) -#include "field_10x26.h" -#elif defined(USE_FIELD_5X52) -#include "field_5x52.h" -#else -#error "Please select field implementation" -#endif - #include "util.h" +#if defined(SECP256K1_WIDEMUL_INT128) +#include "field_5x52.h" +#elif defined(SECP256K1_WIDEMUL_INT64) +#include "field_10x26.h" +#else +#error "Please select wide multiplication implementation" +#endif + /** Normalize a field element. This brings the field element to a canonical representation, reduces * its magnitude to 1, and reduces it modulo field size `p`. */ diff --git a/src/field_impl.h b/src/field_impl.h index 485921a..18e4d2f 100644 --- a/src/field_impl.h +++ b/src/field_impl.h @@ -14,12 +14,12 @@ #include "util.h" #include "num.h" -#if defined(USE_FIELD_10X26) -#include "field_10x26_impl.h" -#elif defined(USE_FIELD_5X52) +#if defined(SECP256K1_WIDEMUL_INT128) #include "field_5x52_impl.h" +#elif defined(SECP256K1_WIDEMUL_INT64) +#include "field_10x26_impl.h" #else -#error "Please select field implementation" +#error "Please select wide multiplication implementation" #endif SECP256K1_INLINE static int secp256k1_fe_equal(const secp256k1_fe *a, const secp256k1_fe *b) { diff --git a/src/scalar.h b/src/scalar.h index 2a74703..95d3e32 100644 --- a/src/scalar.h +++ b/src/scalar.h @@ -8,6 +8,7 @@ #define SECP256K1_SCALAR_H #include "num.h" +#include "util.h" #if defined HAVE_CONFIG_H #include "libsecp256k1-config.h" @@ -15,12 +16,12 @@ #if defined(EXHAUSTIVE_TEST_ORDER) #include "scalar_low.h" -#elif defined(USE_SCALAR_4X64) +#elif defined(SECP256K1_WIDEMUL_INT128) #include "scalar_4x64.h" -#elif defined(USE_SCALAR_8X32) +#elif defined(SECP256K1_WIDEMUL_INT64) #include "scalar_8x32.h" #else -#error "Please select scalar implementation" +#error "Please select wide multiplication implementation" #endif /** Clear a scalar to prevent the leak of sensitive data. */ diff --git a/src/scalar_impl.h b/src/scalar_impl.h index 70cd73d..2ec04b1 100644 --- a/src/scalar_impl.h +++ b/src/scalar_impl.h @@ -16,12 +16,12 @@ #if defined(EXHAUSTIVE_TEST_ORDER) #include "scalar_low_impl.h" -#elif defined(USE_SCALAR_4X64) +#elif defined(SECP256K1_WIDEMUL_INT128) #include "scalar_4x64_impl.h" -#elif defined(USE_SCALAR_8X32) +#elif defined(SECP256K1_WIDEMUL_INT64) #include "scalar_8x32_impl.h" #else -#error "Please select scalar implementation" +#error "Please select wide multiplication implementation" #endif static const secp256k1_scalar secp256k1_scalar_one = SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 1); diff --git a/src/util.h b/src/util.h index 17f6b18..c14bf0e 100644 --- a/src/util.h +++ b/src/util.h @@ -170,13 +170,10 @@ static SECP256K1_INLINE void *manual_alloc(void** prealloc_ptr, size_t alloc_siz # define I64uFORMAT "llu" #endif -#if defined(HAVE___INT128) -# if defined(__GNUC__) -# define SECP256K1_GNUC_EXT __extension__ -# else -# define SECP256K1_GNUC_EXT -# endif -SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t; +#if defined(__GNUC__) +# define SECP256K1_GNUC_EXT __extension__ +#else +# define SECP256K1_GNUC_EXT #endif /* Zero memory if flag == 1. Flag must be 0 or 1. Constant time. */ @@ -213,4 +210,20 @@ static SECP256K1_INLINE void secp256k1_int_cmov(int *r, const int *a, int flag) *r = (int)(r_masked | a_masked); } +/* If USE_FORCE_WIDEMUL_{INT128,INT64} is set, use that wide multiplication implementation. + * Otherwise use the presence of __SIZEOF_INT128__ to decide. + */ +#if defined(USE_FORCE_WIDEMUL_INT128) +# define SECP256K1_WIDEMUL_INT128 1 +#elif defined(USE_FORCE_WIDEMUL_INT64) +# define SECP256K1_WIDEMUL_INT64 1 +#elif defined(__SIZEOF_INT128__) +# define SECP256K1_WIDEMUL_INT128 1 +#else +# define SECP256K1_WIDEMUL_INT64 1 +#endif +#if defined(SECP256K1_WIDEMUL_INT128) +SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t; +#endif + #endif /* SECP256K1_UTIL_H */