Squashed 'src/secp256k1/' changes from 0b70241..b19c000

b19c000 Merge litecoin-project#607: Use size_t shifts when computing a size_t 4d01bc2 Merge litecoin-project#606: travis: Remove unused sudo:false e6d01e9 Use size_t shifts when computing a size_t 7667532 travis: Remove unused sudo:false ee99f12 Merge litecoin-project#599: Switch x86_64 asm to use "i" instead of "n" for immediate values. d58bc93 Switch x86_64 asm to use "i" instead of "n" for immediate values. 05362ee Merge litecoin-project#597: Add $(COMMON_LIB) to exhaustive tests to fix ARM asm build 8348386 Add $(COMMON_LIB) to exhaustive tests to fix ARM asm build aa15154 Merge litecoin-project#568: Fix integer overflow in ecmult_multi_var when n is large 2277af5 Fix integer overflow in ecmult_multi_var when n is large 85d0e1b Merge litecoin-project#591: Make bench_internal obey secp256k1_fe_sqrt's contract wrt aliasing. 1419637 Merge litecoin-project#580: Add trivial ecmult_multi algorithm which does not require a scratch space a697d82 Add trivial ecmult_multi to the benchmark tool bade617 Add trivial ecmult_multi algorithm. It is selected when no scratch space is given and just multiplies and adds the points. 5545e13 Merge litecoin-project#584: configure: Use CFLAGS_FOR_BUILD when checking native compiler 20c5869 Merge litecoin-project#516: improvements to random seed in src/tests.c b76e45d Make bench_internal obey secp256k1_fe_sqrt's contract wrt aliasing. 870a977 Merge litecoin-project#562: Make use of TAG_PUBKEY constants in secp256k1_eckey_pubkey_parse be40c4d Fixup for C90 mixed declarations. c71dd2c Merge litecoin-project#509: Fix algorithm selection in bench_ecmult 6492bf8 Merge litecoin-project#518: Summarize build options after running configure 0e9ada1 Merge litecoin-project#567: Correct order of libs returned on pkg-config --libs --static libsecp2… e96901a Merge litecoin-project#587: Make randomization of a non-signing context a noop 58df8d0 Merge litecoin-project#511: Portability fix for the configure scripts generated 2ebdad7 Merge litecoin-project#552: Make constants static: 1c131af Merge litecoin-project#551: secp256k1_fe_sqrt: Verify that the arguments don't alias. ba698f8 Merge litecoin-project#539: Assorted minor corrections 949e85b Merge litecoin-project#550: Optimize secp256k1_fe_normalize_weak calls. a34bcaa Actually pass CFLAGS_FOR_BUILD and LDFLAGS_FOR_BUILD to linker 2d5f4ce configure: Use CFLAGS_FOR_BUILD when checking native compiler b408c6a Merge litecoin-project#579: Use __GNUC_PREREQ for detecting __builtin_expect 6198375 Make randomization of a non-signing context a noop c663397 Use __GNUC_PREREQ for detecting __builtin_expect e34ceb3 Merge litecoin-project#557: Eliminate scratch memory used when generating contexts b3bf5f9 ecmult_impl: expand comment to explain how effective affine interacts with everything efa783f Store z-ratios in the 'x' coord they'll recover ffd3b34 add `secp256k1_ge_set_all_gej_var` test which deals with many infinite points 84740ac ecmult_impl: save one fe_inv_var 4704527 ecmult_impl: eliminate scratch memory used when generating context 7f7a2ed ecmult_gen_impl: eliminate scratch memory used when generating context 314a61d Merge litecoin-project#553: add static context object which has no capabilities 89a20a8 Correct order of libs returned on pkg-config --libs --static libsecp256k1 call. 1086fda Merge litecoin-project#354: [ECDH API change] Support custom hash function d3cb1f9 Make use of TAG_PUBKEY constants in secp256k1_eckey_pubkey_parse 40fde61 prevent attempts to modify `secp256k1_context_no_precomp` ed7c084 add static context object which has no capabilities 496c5b4 Make constants static: static const secp256k1_ge secp256k1_ge_const_g; static const int CURVE_B; bf8b86c secp256k1_fe_sqrt: Verify that the arguments don't alias. 9bd89c8 Optimize secp256k1_fe_normalize_weak calls. Move secp256k1_fe_normalize_weak calls out of ECMULT_TABLE_GET_GE and ECMULT_TABLE_GET_GE_STORAGE and into secp256k1_ge_globalz_set_table_gej instead. 52ab96f clean dependendies in field_*_impl.h deff5ed Correct math typos in field_*.h 4efb3f8 Add check that restrict pointers don't alias with all parameters. 1e6f1f5 Merge litecoin-project#529: fix tests.c in the count == 0 case c8fbc3c [ECDH API change] Allow pass arbitrary data to hash function b00be65 [ECDH API change] Support custom hash function 95e99f1 fix tests.c in the count == 0 case 452d8e4 Merge litecoin-project#523: scratch: add stack frame support 6fe5043 scratch: add stack frame support 9bc2e26 Merge litecoin-project#522: parameterize ecmult_const over input size 7c1b91b parameterize ecmult_const over input size dbc3ddd Merge litecoin-project#513: Increase sparsity of pippenger fixed window naf representation 3965027 Summarize build options in configure script 0f05173 Fix algorithm selection in bench_ecmult fb9271d Merge litecoin-project#510: add a couple missing `const`s to ecmult_pippenger_wnaf cd5f602 Merge litecoin-project#515: Fix typo 09146ae Merge litecoin-project#512: secp256k1_ec_privkey_negate - fix documentation ec0a7b3 Don't touch leading zeros in wnaf_fixed. 9e36d1b Fix bug in wnaf_fixed where the wnaf array is not completely zeroed when given a 0 scalar. 96f68a0 Don't invert scalar in wnaf_fixed when it is even because a caller might intentionally give a scalar with many leading zeros. 8b3841c fix bug in fread() failure check cddef0c tests: add warning message when /dev/urandom fails 9b7c47a Fix typo 6dbb007 Increase sparsity of pippenger fixed window naf representation 1646ace secp256k1_ec_privkey_negate - fix documentation 270f6c8 Portability fix for the configure scripts generated 9b3ff03 add a couple missing `const`s to ecmult_pippenger_wnaf cd329db Merge litecoin-project#460: [build] Update ax_jni_include_dir.m4 macro 7f9c1a1 Merge litecoin-project#498: tests: Avoid calling fclose(...) with an invalid argument f99aa8d Merge litecoin-project#499: tests: Make sure we get the requested number of bytes from /dev/urandom b549d3d Merge litecoin-project#472: [build] Set --enable-jni to no by default instead of auto. d333521 Merge litecoin-project#494: Support OpenSSL versions >= 1.1 for ENABLE_OPENSSL_TESTS 2ef8ea5 Merge litecoin-project#495: Add bench_ecmult to .gitignore 82a96e4 tests: Make sure we get the requested number of bytes from /dev/urandom 5aae5b5 Avoid calling fclose(...) with an invalid argument cb32940 Add bench_ecmult to .gitignore 31abd3a Support OpenSSL versions >= 1.1 for ENABLE_OPENSSL_TESTS c95f6f1 Merge litecoin-project#487: fix tests typo, s/changed/unchanged fb46c83 Merge litecoin-project#463: Reduce usage of hardcoded size constants 02f5001 Merge litecoin-project#490: Disambiguate bench functions and types 1f46d60 Disambiguate bench functions and types f54c6c5 Merge litecoin-project#480: Enable benchmark building by default c77fc08 Merge litecoin-project#486: Add pippenger_wnaf for multi-multiplication d2f9c6b Use more precise pippenger bucket windows 4c950bb Save some additions per window in _pippenger_wnaf a58f543 Add flags for choosing algorithm in ecmult_multi benchmark 36b22c9 Use scratch space dependent batching in ecmult_multi 355a38f Add pippenger_wnaf ecmult_multi bc65aa7 Add bench_ecmult dba5471 Add ecmult_multi tests 8c1c831 Generalize Strauss to support multiple points 548de42 add resizeable scratch space API 0e96cdc fix typo, s/changed/unchanged c7680e5 Reduce usage of hardcoded size constants 6ad5cdb Merge litecoin-project#479: Get rid of reserved _t in type names 7a78f60 Print whether we're building benchmarks 4afec9f Build benchmarks by default d1dc9df Get rid of reserved _t in type names 57752d2 [build] Set --enable-jni to no by default instead of auto. e7daa9b [build] Tweak JNI macro to warn instead of error for JNI not found. 5b22977 [build] Update ax_jni_include_dir.m4 macro to deal with recent versions of macOS git-subtree-dir: src/secp256k1 git-subtree-split: b19c000
thrasher- · Mar 31, 2019 · 5424598 · 5424598
1 parent fd86f99
commit 5424598
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Showing 44 changed files with 2,415 additions and 416 deletions.
diff --git a/.gitignore b/.gitignore
@@ -1,5 +1,6 @@
 bench_inv
 bench_ecdh
+bench_ecmult
 bench_sign
 bench_verify
 bench_schnorr_verify

diff --git a/.travis.yml b/.travis.yml
@@ -1,5 +1,5 @@
 language: c
-sudo: false
+os: linux
 addons:
   apt:
     packages: libgmp-dev
@@ -11,7 +11,7 @@ cache:
   - src/java/guava/
 env:
   global:
-    - FIELD=auto  BIGNUM=auto  SCALAR=auto  ENDOMORPHISM=no  STATICPRECOMPUTATION=yes  ASM=no  BUILD=check  EXTRAFLAGS=  HOST=  ECDH=no  RECOVERY=no  EXPERIMENTAL=no
+    - FIELD=auto  BIGNUM=auto  SCALAR=auto  ENDOMORPHISM=no  STATICPRECOMPUTATION=yes  ASM=no  BUILD=check  EXTRAFLAGS=  HOST=  ECDH=no  RECOVERY=no  EXPERIMENTAL=no  JNI=no
     - GUAVA_URL=https://search.maven.org/remotecontent?filepath=com/google/guava/guava/18.0/guava-18.0.jar GUAVA_JAR=src/java/guava/guava-18.0.jar
   matrix:
     - SCALAR=32bit    RECOVERY=yes
@@ -29,7 +29,7 @@ env:
     - BUILD=distcheck
     - EXTRAFLAGS=CPPFLAGS=-DDETERMINISTIC
     - EXTRAFLAGS=CFLAGS=-O0
-    - BUILD=check-java ECDH=yes EXPERIMENTAL=yes
+    - BUILD=check-java JNI=yes ECDH=yes EXPERIMENTAL=yes
 matrix:
   fast_finish: true
   include:
@@ -65,5 +65,4 @@ before_script: ./autogen.sh
 script:
  - if [ -n "$HOST" ]; then export USE_HOST="--host=$HOST"; fi
  - if [ "x$HOST" = "xi686-linux-gnu" ]; then export CC="$CC -m32"; fi
- - ./configure --enable-experimental=$EXPERIMENTAL --enable-endomorphism=$ENDOMORPHISM --with-field=$FIELD --with-bignum=$BIGNUM --with-scalar=$SCALAR --enable-ecmult-static-precomputation=$STATICPRECOMPUTATION --enable-module-ecdh=$ECDH --enable-module-recovery=$RECOVERY $EXTRAFLAGS $USE_HOST && make -j2 $BUILD
-os: linux
+ - ./configure --enable-experimental=$EXPERIMENTAL --enable-endomorphism=$ENDOMORPHISM --with-field=$FIELD --with-bignum=$BIGNUM --with-scalar=$SCALAR --enable-ecmult-static-precomputation=$STATICPRECOMPUTATION --enable-module-ecdh=$ECDH --enable-module-recovery=$RECOVERY --enable-jni=$JNI $EXTRAFLAGS $USE_HOST && make -j2 $BUILD
diff --git a/Makefile.am b/Makefile.am
@@ -42,6 +42,8 @@ noinst_HEADERS += src/field_5x52_asm_impl.h
 noinst_HEADERS += src/java/org_bitcoin_NativeSecp256k1.h
 noinst_HEADERS += src/java/org_bitcoin_Secp256k1Context.h
 noinst_HEADERS += src/util.h
+noinst_HEADERS += src/scratch.h
+noinst_HEADERS += src/scratch_impl.h
 noinst_HEADERS += src/testrand.h
 noinst_HEADERS += src/testrand_impl.h
 noinst_HEADERS += src/hash.h
@@ -79,14 +81,17 @@ libsecp256k1_jni_la_CPPFLAGS = -DSECP256K1_BUILD $(JNI_INCLUDES)
 
 noinst_PROGRAMS =
 if USE_BENCHMARK
-noinst_PROGRAMS += bench_verify bench_sign bench_internal
+noinst_PROGRAMS += bench_verify bench_sign bench_internal bench_ecmult
 bench_verify_SOURCES = src/bench_verify.c
 bench_verify_LDADD = libsecp256k1.la $(SECP_LIBS) $(SECP_TEST_LIBS) $(COMMON_LIB)
 bench_sign_SOURCES = src/bench_sign.c
 bench_sign_LDADD = libsecp256k1.la $(SECP_LIBS) $(SECP_TEST_LIBS) $(COMMON_LIB)
 bench_internal_SOURCES = src/bench_internal.c
 bench_internal_LDADD = $(SECP_LIBS) $(COMMON_LIB)
 bench_internal_CPPFLAGS = -DSECP256K1_BUILD $(SECP_INCLUDES)
+bench_ecmult_SOURCES = src/bench_ecmult.c
+bench_ecmult_LDADD = $(SECP_LIBS) $(COMMON_LIB)
+bench_ecmult_CPPFLAGS = -DSECP256K1_BUILD $(SECP_INCLUDES)
 endif
 
 TESTS =
@@ -109,7 +114,7 @@ exhaustive_tests_CPPFLAGS = -DSECP256K1_BUILD -I$(top_srcdir)/src $(SECP_INCLUDE
 if !ENABLE_COVERAGE
 exhaustive_tests_CPPFLAGS += -DVERIFY
 endif
-exhaustive_tests_LDADD = $(SECP_LIBS)
+exhaustive_tests_LDADD = $(SECP_LIBS) $(COMMON_LIB)
 exhaustive_tests_LDFLAGS = -static
 TESTS += exhaustive_tests
 endif
@@ -146,19 +151,19 @@ endif
 
 if USE_ECMULT_STATIC_PRECOMPUTATION
 CPPFLAGS_FOR_BUILD +=-I$(top_srcdir)
-CFLAGS_FOR_BUILD += -Wall -Wextra -Wno-unused-function
 
 gen_context_OBJECTS = gen_context.o
 gen_context_BIN = gen_context$(BUILD_EXEEXT)
 gen_%.o: src/gen_%.c
 	$(CC_FOR_BUILD) $(CPPFLAGS_FOR_BUILD) $(CFLAGS_FOR_BUILD) -c $< -o $@
 
 $(gen_context_BIN): $(gen_context_OBJECTS)
-	$(CC_FOR_BUILD) $^ -o $@
+	$(CC_FOR_BUILD) $(CFLAGS_FOR_BUILD) $(LDFLAGS_FOR_BUILD) $^ -o $@
 
 $(libsecp256k1_la_OBJECTS): src/ecmult_static_context.h
 $(tests_OBJECTS): src/ecmult_static_context.h
 $(bench_internal_OBJECTS): src/ecmult_static_context.h
+$(bench_ecmult_OBJECTS): src/ecmult_static_context.h
 
 src/ecmult_static_context.h: $(gen_context_BIN)
 	./$(gen_context_BIN)

diff --git a/build-aux/m4/ax_jni_include_dir.m4 b/build-aux/m4/ax_jni_include_dir.m4
@@ -1,5 +1,5 @@
 # ===========================================================================
-#    http://www.gnu.org/software/autoconf-archive/ax_jni_include_dir.html
+#    https://www.gnu.org/software/autoconf-archive/ax_jni_include_dir.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -44,7 +44,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 10
+#serial 14
 
 AU_ALIAS([AC_JNI_INCLUDE_DIR], [AX_JNI_INCLUDE_DIR])
 AC_DEFUN([AX_JNI_INCLUDE_DIR],[
@@ -66,40 +66,45 @@ else
 fi
 
 case "$host_os" in
-        darwin*)        _JTOPDIR=`echo "$_JTOPDIR" | sed -e 's:/[[^/]]*$::'`
-                        _JINC="$_JTOPDIR/Headers";;
-        *)              _JINC="$_JTOPDIR/include";;
+        darwin*)        # Apple Java headers are inside the Xcode bundle.
+            macos_version=$(sw_vers -productVersion | sed -n -e 's/^@<:@0-9@:>@*.\(@<:@0-9@:>@*\).@<:@0-9@:>@*/\1/p')
+            if @<:@ "$macos_version" -gt "7" @:>@; then
+                _JTOPDIR="$(xcrun --show-sdk-path)/System/Library/Frameworks/JavaVM.framework"
+                _JINC="$_JTOPDIR/Headers"
+            else
+                _JTOPDIR="/System/Library/Frameworks/JavaVM.framework"
+                _JINC="$_JTOPDIR/Headers"
+            fi
+            ;;
+        *) _JINC="$_JTOPDIR/include";;
 esac
 _AS_ECHO_LOG([_JTOPDIR=$_JTOPDIR])
 _AS_ECHO_LOG([_JINC=$_JINC])
 
 # On Mac OS X 10.6.4, jni.h is a symlink:
 # /System/Library/Frameworks/JavaVM.framework/Versions/Current/Headers/jni.h
 # -> ../../CurrentJDK/Headers/jni.h.
-
 AC_CACHE_CHECK(jni headers, ac_cv_jni_header_path,
 [
-if test -f "$_JINC/jni.h"; then
-  ac_cv_jni_header_path="$_JINC"
-  JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $ac_cv_jni_header_path"
-else
-  _JTOPDIR=`echo "$_JTOPDIR" | sed -e 's:/[[^/]]*$::'`
-  if test -f "$_JTOPDIR/include/jni.h"; then
-    ac_cv_jni_header_path="$_JTOPDIR/include"
+  if test -f "$_JINC/jni.h"; then
+    ac_cv_jni_header_path="$_JINC"
     JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $ac_cv_jni_header_path"
   else
-    ac_cv_jni_header_path=none
+    _JTOPDIR=`echo "$_JTOPDIR" | sed -e 's:/[[^/]]*$::'`
+    if test -f "$_JTOPDIR/include/jni.h"; then
+      ac_cv_jni_header_path="$_JTOPDIR/include"
+      JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $ac_cv_jni_header_path"
+    else
+      ac_cv_jni_header_path=none
+    fi
   fi
-fi
 ])
 
-
-
 # get the likely subdirectories for system specific java includes
 case "$host_os" in
 bsdi*)          _JNI_INC_SUBDIRS="bsdos";;
-darwin*)        _JNI_INC_SUBDIRS="darwin";;
 freebsd*)       _JNI_INC_SUBDIRS="freebsd";;
+darwin*)        _JNI_INC_SUBDIRS="darwin";;
 linux*)         _JNI_INC_SUBDIRS="linux genunix";;
 osf*)           _JNI_INC_SUBDIRS="alpha";;
 solaris*)       _JNI_INC_SUBDIRS="solaris";;
@@ -112,9 +117,9 @@ if test "x$ac_cv_jni_header_path" != "xnone"; then
   # add any subdirectories that are present
   for JINCSUBDIR in $_JNI_INC_SUBDIRS
   do
-      if test -d "$_JTOPDIR/include/$JINCSUBDIR"; then
-           JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $_JTOPDIR/include/$JINCSUBDIR"
-      fi
+    if test -d "$_JTOPDIR/include/$JINCSUBDIR"; then
+         JNI_INCLUDE_DIRS="$JNI_INCLUDE_DIRS $_JTOPDIR/include/$JINCSUBDIR"
+    fi
   done
 fi
 ])

diff --git a/build-aux/m4/bitcoin_secp.m4 b/build-aux/m4/bitcoin_secp.m4
@@ -48,7 +48,6 @@ if test x"$has_libcrypto" = x"yes" && test x"$has_openssl_ec" = x; then
     EC_KEY_free(eckey);
     ECDSA_SIG *sig_openssl;
     sig_openssl = ECDSA_SIG_new();
-    (void)sig_openssl->r;
     ECDSA_SIG_free(sig_openssl);
   ]])],[has_openssl_ec=yes],[has_openssl_ec=no])
   AC_MSG_RESULT([$has_openssl_ec])

diff --git a/configure.ac b/configure.ac
@@ -85,9 +85,9 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[char foo;]])],
     ])
 
 AC_ARG_ENABLE(benchmark,
-    AS_HELP_STRING([--enable-benchmark],[compile benchmark (default is no)]),
+    AS_HELP_STRING([--enable-benchmark],[compile benchmark (default is yes)]),
     [use_benchmark=$enableval],
-    [use_benchmark=no])
+    [use_benchmark=yes])
 
 AC_ARG_ENABLE(coverage,
     AS_HELP_STRING([--enable-coverage],[enable compiler flags to support kcov coverage analysis]),
@@ -135,9 +135,9 @@ AC_ARG_ENABLE(module_recovery,
     [enable_module_recovery=no])
 
 AC_ARG_ENABLE(jni,
-    AS_HELP_STRING([--enable-jni],[enable libsecp256k1_jni (default is auto)]),
+    AS_HELP_STRING([--enable-jni],[enable libsecp256k1_jni (default is no)]),
     [use_jni=$enableval],
-    [use_jni=auto])
+    [use_jni=no])
 
 AC_ARG_WITH([field], [AS_HELP_STRING([--with-field=64bit|32bit|auto],
 [Specify Field Implementation. Default is auto])],[req_field=$withval], [req_field=auto])
@@ -153,12 +153,6 @@ AC_ARG_WITH([asm], [AS_HELP_STRING([--with-asm=x86_64|arm|no|auto]
 
 AC_CHECK_TYPES([__int128])
 
-AC_MSG_CHECKING([for __builtin_expect])
-AC_COMPILE_IFELSE([AC_LANG_SOURCE([[void myfunc() {__builtin_expect(0,0);}]])],
-    [ AC_MSG_RESULT([yes]);AC_DEFINE(HAVE_BUILTIN_EXPECT,1,[Define this symbol if __builtin_expect is available]) ],
-    [ AC_MSG_RESULT([no])
-    ])
-
 if test x"$enable_coverage" = x"yes"; then
     AC_DEFINE(COVERAGE, 1, [Define this symbol to compile out all VERIFY code])
     CFLAGS="$CFLAGS -O0 --coverage"
@@ -168,27 +162,54 @@ else
 fi
 
 if test x"$use_ecmult_static_precomputation" != x"no"; then
+  # Temporarily switch to an environment for the native compiler
   save_cross_compiling=$cross_compiling
   cross_compiling=no
-  TEMP_CC="$CC"
+  SAVE_CC="$CC"
   CC="$CC_FOR_BUILD"
-  AC_MSG_CHECKING([native compiler: ${CC_FOR_BUILD}])
+  SAVE_CFLAGS="$CFLAGS"
+  CFLAGS="$CFLAGS_FOR_BUILD"
+  SAVE_CPPFLAGS="$CPPFLAGS"
+  CPPFLAGS="$CPPFLAGS_FOR_BUILD"
+  SAVE_LDFLAGS="$LDFLAGS"
+  LDFLAGS="$LDFLAGS_FOR_BUILD"
+
+  warn_CFLAGS_FOR_BUILD="-Wall -Wextra -Wno-unused-function"
+  saved_CFLAGS="$CFLAGS"
+  CFLAGS="$CFLAGS $warn_CFLAGS_FOR_BUILD"
+  AC_MSG_CHECKING([if native ${CC_FOR_BUILD} supports ${warn_CFLAGS_FOR_BUILD}])
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[char foo;]])],
+      [ AC_MSG_RESULT([yes]) ],
+      [ AC_MSG_RESULT([no])
+        CFLAGS="$saved_CFLAGS"
+      ])
+
+  AC_MSG_CHECKING([for working native compiler: ${CC_FOR_BUILD}])
   AC_RUN_IFELSE(
-    [AC_LANG_PROGRAM([], [return 0])],
+    [AC_LANG_PROGRAM([], [])],
     [working_native_cc=yes],
     [working_native_cc=no],[dnl])
-  CC="$TEMP_CC"
+
+  CFLAGS_FOR_BUILD="$CFLAGS"
+
+  # Restore the environment
   cross_compiling=$save_cross_compiling
+  CC="$SAVE_CC"
+  CFLAGS="$SAVE_CFLAGS"
+  CPPFLAGS="$SAVE_CPPFLAGS"
+  LDFLAGS="$SAVE_LDFLAGS"
 
   if test x"$working_native_cc" = x"no"; then
+    AC_MSG_RESULT([no])
     set_precomp=no
+    m4_define([please_set_for_build], [Please set CC_FOR_BUILD, CFLAGS_FOR_BUILD, CPPFLAGS_FOR_BUILD, and/or LDFLAGS_FOR_BUILD.])
     if test x"$use_ecmult_static_precomputation" = x"yes";  then
-      AC_MSG_ERROR([${CC_FOR_BUILD} does not produce working binaries. Please set CC_FOR_BUILD])
+      AC_MSG_ERROR([native compiler ${CC_FOR_BUILD} does not produce working binaries. please_set_for_build])
     else
-      AC_MSG_RESULT([${CC_FOR_BUILD} does not produce working binaries. Please set CC_FOR_BUILD])
+      AC_MSG_WARN([Disabling statically generated ecmult table because the native compiler ${CC_FOR_BUILD} does not produce working binaries. please_set_for_build])
     fi
   else
-    AC_MSG_RESULT([ok])
+    AC_MSG_RESULT([yes])
     set_precomp=yes
   fi
 else
@@ -441,17 +462,6 @@ if test x"$use_external_asm" = x"yes"; then
   AC_DEFINE(USE_EXTERNAL_ASM, 1, [Define this symbol if an external (non-inline) assembly implementation is used])
 fi
 
-AC_MSG_NOTICE([Using static precomputation: $set_precomp])
-AC_MSG_NOTICE([Using assembly optimizations: $set_asm])
-AC_MSG_NOTICE([Using field implementation: $set_field])
-AC_MSG_NOTICE([Using bignum implementation: $set_bignum])
-AC_MSG_NOTICE([Using scalar implementation: $set_scalar])
-AC_MSG_NOTICE([Using endomorphism optimizations: $use_endomorphism])
-AC_MSG_NOTICE([Building for coverage analysis: $enable_coverage])
-AC_MSG_NOTICE([Building ECDH module: $enable_module_ecdh])
-AC_MSG_NOTICE([Building ECDSA pubkey recovery module: $enable_module_recovery])
-AC_MSG_NOTICE([Using jni: $use_jni])
-
 if test x"$enable_experimental" = x"yes"; then
   AC_MSG_NOTICE([******])
   AC_MSG_NOTICE([WARNING: experimental build])
@@ -481,7 +491,7 @@ AM_CONDITIONAL([USE_BENCHMARK], [test x"$use_benchmark" = x"yes"])
 AM_CONDITIONAL([USE_ECMULT_STATIC_PRECOMPUTATION], [test x"$set_precomp" = x"yes"])
 AM_CONDITIONAL([ENABLE_MODULE_ECDH], [test x"$enable_module_ecdh" = x"yes"])
 AM_CONDITIONAL([ENABLE_MODULE_RECOVERY], [test x"$enable_module_recovery" = x"yes"])
-AM_CONDITIONAL([USE_JNI], [test x"$use_jni" == x"yes"])
+AM_CONDITIONAL([USE_JNI], [test x"$use_jni" = x"yes"])
 AM_CONDITIONAL([USE_EXTERNAL_ASM], [test x"$use_external_asm" = x"yes"])
 AM_CONDITIONAL([USE_ASM_ARM], [test x"$set_asm" = x"arm"])
 
@@ -491,3 +501,24 @@ unset PKG_CONFIG_PATH
 PKG_CONFIG_PATH="$PKGCONFIG_PATH_TEMP"
 
 AC_OUTPUT
+
+echo
+echo "Build Options:"
+echo "  with endomorphism   = $use_endomorphism"
+echo "  with ecmult precomp = $set_precomp"
+echo "  with jni            = $use_jni"
+echo "  with benchmarks     = $use_benchmark"
+echo "  with coverage       = $enable_coverage"
+echo "  module ecdh         = $enable_module_ecdh"
+echo "  module recovery     = $enable_module_recovery"
+echo
+echo "  asm                 = $set_asm"
+echo "  bignum              = $set_bignum"
+echo "  field               = $set_field"
+echo "  scalar              = $set_scalar"
+echo
+echo "  CC                  = $CC"
+echo "  CFLAGS              = $CFLAGS"
+echo "  CPPFLAGS            = $CPPFLAGS"
+echo "  LDFLAGS             = $LDFLAGS"
+echo