Merge #20147: Update libsecp256k1 (endomorphism, test improvements)

52380bf304b1c02dda23f1e2fad0159e29b2f7a2 Squashed 'src/secp256k1/' changes from 8ab24e8dad..c6b6b8f1bb (Pieter Wuille)

Pull request description:

  This updates the libsecp256k1 subtree to the latest master, which includes:

  * Enabling the GLV endomorphism optimization by default (and removing support for the non-GLV EC multiplication)
  * Added a proof for the correctness of the lambda split algorithm by roconnor-blockstream (other code was relying on the fact that it always outputs 128 bit results, which isn't at all obvious).
  * Improved exhaustive tests, in particular for the Schnorr signature module
  * Various other testing and CI improvements

ACKs for top commit:
  fanquake:
    ACK 9e5626d2a8ddbbd7640ff53f89f3a7021d747633 - performed a squash and checked that the changes were the same. The non-endomorphism code has now been ripped out.
  benthecarman:
    ACK 9e5626d

Tree-SHA512: 50fda5f3f934ee525f01cfc15e4f5efbc5261a97f2b77fe1b3453ee0edcf1281ad74ab4532a2fe1fe907652dd47023beff8cf3d73bf34f65ac914a694b9e7110

1 files changed, 17 insertions, 14 deletions

diff --git a/src/secp256k1/configure.ac b/src/secp256k1/configure.ac
index 6fe8984f4d..5a078e6c81 100644
--- a/src/secp256k1/configure.ac
+++ b/src/secp256k1/configure.ac
@@ -67,7 +67,7 @@ esac
 
 CFLAGS="-W $CFLAGS"
 
-warn_CFLAGS="-std=c89 -pedantic -Wall -Wextra -Wcast-align -Wnested-externs -Wshadow -Wstrict-prototypes -Wno-unused-function -Wno-long-long -Wno-overlength-strings"
+warn_CFLAGS="-std=c89 -pedantic -Wall -Wextra -Wcast-align -Wnested-externs -Wshadow -Wstrict-prototypes -Wundef -Wno-unused-function -Wno-long-long -Wno-overlength-strings"
 saved_CFLAGS="$CFLAGS"
 CFLAGS="$warn_CFLAGS $CFLAGS"
 AC_MSG_CHECKING([if ${CC} supports ${warn_CFLAGS}])
@@ -116,11 +116,6 @@ AC_ARG_ENABLE(exhaustive_tests,
     [use_exhaustive_tests=$enableval],
     [use_exhaustive_tests=yes])
 
-AC_ARG_ENABLE(endomorphism,
-    AS_HELP_STRING([--enable-endomorphism],[enable endomorphism [default=no]]),
-    [use_endomorphism=$enableval],
-    [use_endomorphism=no])
-
 AC_ARG_ENABLE(ecmult_static_precomputation,
     AS_HELP_STRING([--enable-ecmult-static-precomputation],[enable precomputed ecmult table for signing [default=auto]]),
     [use_ecmult_static_precomputation=$enableval],
@@ -164,8 +159,7 @@ AC_ARG_WITH([asm], [AS_HELP_STRING([--with-asm=x86_64|arm|no|auto],
 AC_ARG_WITH([ecmult-window], [AS_HELP_STRING([--with-ecmult-window=SIZE|auto],
 [window size for ecmult precomputation for verification, specified as integer in range [2..24].]
 [Larger values result in possibly better performance at the cost of an exponentially larger precomputed table.]
-[The table will store 2^(SIZE-2) * 64 bytes of data but can be larger in memory due to platform-specific padding and alignment.]
-[If the endomorphism optimization is enabled, two tables of this size are used instead of only one.]
+[The table will store 2^(SIZE-1) * 64 bytes of data but can be larger in memory due to platform-specific padding and alignment.]
 ["auto" is a reasonable setting for desktop machines (currently 15). [default=auto]]
 )],
 [req_ecmult_window=$withval], [req_ecmult_window=auto])
@@ -178,7 +172,21 @@ AC_ARG_WITH([ecmult-gen-precision], [AS_HELP_STRING([--with-ecmult-gen-precision
 )],
 [req_ecmult_gen_precision=$withval], [req_ecmult_gen_precision=auto])
 
-AC_CHECK_HEADER([valgrind/memcheck.h], [enable_valgrind=yes], [enable_valgrind=no], [])
+AC_ARG_WITH([valgrind], [AS_HELP_STRING([--with-valgrind=yes|no|auto],
+[Build with extra checks for running inside Valgrind [default=auto]]
+)],
+[req_valgrind=$withval], [req_valgrind=auto])
+
+if test x"$req_valgrind" = x"no"; then
+  enable_valgrind=no
+else
+  AC_CHECK_HEADER([valgrind/memcheck.h], [enable_valgrind=yes], [
+    if test x"$req_valgrind" = x"yes"; then
+      AC_MSG_ERROR([Valgrind support explicitly requested but valgrind/memcheck.h header not available])
+    fi
+    enable_valgrind=no
+  ], [])
+fi
 AM_CONDITIONAL([VALGRIND_ENABLED],[test "$enable_valgrind" = "yes"])
 
 if test x"$enable_coverage" = x"yes"; then
@@ -415,10 +423,6 @@ if test x"$set_bignum" = x"gmp"; then
   SECP_INCLUDES="$SECP_INCLUDES $GMP_CPPFLAGS"
 fi
 
-if test x"$use_endomorphism" = x"yes"; then
-  AC_DEFINE(USE_ENDOMORPHISM, 1, [Define this symbol to use endomorphism optimization])
-fi
-
 if test x"$set_precomp" = x"yes"; then
   AC_DEFINE(USE_ECMULT_STATIC_PRECOMPUTATION, 1, [Define this symbol to use a statically generated ecmult table])
 fi
@@ -500,7 +504,6 @@ AC_OUTPUT
 
 echo
 echo "Build Options:"
-echo "  with endomorphism       = $use_endomorphism"
 echo "  with ecmult precomp     = $set_precomp"
 echo "  with external callbacks = $use_external_default_callbacks"
 echo "  with benchmarks         = $use_benchmark"