Merge #1042: Follow-ups to making all tables fully static

e05da9e Fix c++ build (Pieter Wuille)
c45386d Cleanup preprocessor indentation in precompute{,d}_ecmult{,_gen} (Pieter Wuille)
19d96e1 Split off .c file from precomputed_ecmult.h (Pieter Wuille)
1a6691a Split off .c file from precomputed_ecmult_gen.h (Pieter Wuille)
bb36331 Simplify precompute_ecmult_print_* (Pieter Wuille)
38cd84a Compute ecmult tables at runtime for tests_exhaustive (Pieter Wuille)
e458ec2 Move ecmult table computation code to separate file (Pieter Wuille)
fc1bf9f Split ecmult table computation and printing (Pieter Wuille)
31feab0 Rename function secp256k1_ecmult_gen_{create_prec -> compute}_table (Pieter Wuille)
725370c Rename ecmult_gen_prec -> ecmult_gen_compute_table (Pieter Wuille)
075252c Rename ecmult_static_pre_g -> precomputed_ecmult (Pieter Wuille)
7cf47f7 Rename ecmult_gen_static_prec_table -> precomputed_ecmult_gen (Pieter Wuille)
f95b810 Rename gen_ecmult_static_pre_g -> precompute_ecmult (Pieter Wuille)
bae7768 Rename gen_ecmult_gen_static_prec_table -> precompute_ecmult_gen (Pieter Wuille)

Pull request description:

  This PR implements a number of changes to follow up after merging #988:

  * Naming consistency:
    * All precomputed table files now have name `precomputed_*.*`
    * All source files related to the creation of the precomputed table files have name `precompute_*.*`.
    * All source files related to the computation of tables (whether they go in precomputed files or not) have name `*_compute_table.*`.
  * Make the tables for exhaustive tests be computed at runtime rather than compile time (this was already the case for ecmult_gen, but not ecmult). This is a preparation for the next point, as the alternative would be to have separate precomputed libraries for the exhaustive tests and other binaries.
  * Moves the actual tables to separate `precomputed_*.c` files, which are compiled only once as part of a new `libsecp256k1_precomputed.la`, included where relevant. The corresponding `precomputed_*.h` file are normal source files.

  Retry of #1041.

ACKs for top commit:
  real-or-random:
    ACK e05da9e
  jonasnick:
    ACK e05da9e

Tree-SHA512: 71eadd66e30e511b786e910755e0eda53330dfa163b37e33602c3392f7b893569f56d3ca9870e85cbb3de83880fc5aef61ac3d55d759d7395086a69023f13f03

Author: real-or-random

.gitattributes

@@ -1,2 +1,2 @@
-src/ecmult_static_pre_g.h linguist-generated
-src/ecmult_gen_static_prec_table.h linguist-generated
+src/precomputed_ecmult.c linguist-generated
+src/precomputed_ecmult_gen.c linguist-generated

.gitignore

@@ -3,8 +3,8 @@ bench_ecmult
 bench_internal
 tests
 exhaustive_tests
-gen_ecmult_gen_static_prec_table
-gen_ecmult_static_pre_g
+precompute_ecmult_gen
+precompute_ecmult
 valgrind_ctime_test
 *.exe
 *.so

Makefile.am

@@ -26,12 +26,14 @@ noinst_HEADERS += src/eckey.h
 noinst_HEADERS += src/eckey_impl.h
 noinst_HEADERS += src/ecmult.h
 noinst_HEADERS += src/ecmult_impl.h
+noinst_HEADERS += src/ecmult_compute_table.h
+noinst_HEADERS += src/ecmult_compute_table_impl.h
 noinst_HEADERS += src/ecmult_const.h
 noinst_HEADERS += src/ecmult_const_impl.h
 noinst_HEADERS += src/ecmult_gen.h
 noinst_HEADERS += src/ecmult_gen_impl.h
-noinst_HEADERS += src/ecmult_gen_prec.h
-noinst_HEADERS += src/ecmult_gen_prec_impl.h
+noinst_HEADERS += src/ecmult_gen_compute_table.h
+noinst_HEADERS += src/ecmult_gen_compute_table_impl.h
 noinst_HEADERS += src/field_10x26.h
 noinst_HEADERS += src/field_10x26_impl.h
 noinst_HEADERS += src/field_5x52.h
@@ -42,6 +44,8 @@ noinst_HEADERS += src/modinv32.h
 noinst_HEADERS += src/modinv32_impl.h
 noinst_HEADERS += src/modinv64.h
 noinst_HEADERS += src/modinv64_impl.h
+noinst_HEADERS += src/precomputed_ecmult.h
+noinst_HEADERS += src/precomputed_ecmult_gen.h
 noinst_HEADERS += src/assumptions.h
 noinst_HEADERS += src/util.h
 noinst_HEADERS += src/scratch.h
@@ -60,12 +64,17 @@ noinst_HEADERS += contrib/lax_der_parsing.c
 noinst_HEADERS += contrib/lax_der_privatekey_parsing.h
 noinst_HEADERS += contrib/lax_der_privatekey_parsing.c
 
+PRECOMPUTED_LIB = libsecp256k1_precomputed.la
+noinst_LTLIBRARIES = $(PRECOMPUTED_LIB)
+libsecp256k1_precomputed_la_SOURCES =  src/precomputed_ecmult.c src/precomputed_ecmult_gen.c
+libsecp256k1_precomputed_la_CPPFLAGS = $(SECP_INCLUDES)
+
 if USE_EXTERNAL_ASM
 COMMON_LIB = libsecp256k1_common.la
-noinst_LTLIBRARIES = $(COMMON_LIB)
 else
 COMMON_LIB =
 endif
+noinst_LTLIBRARIES += $(COMMON_LIB)
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = libsecp256k1.pc
@@ -78,7 +87,7 @@ endif
 
 libsecp256k1_la_SOURCES = src/secp256k1.c
 libsecp256k1_la_CPPFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/src $(SECP_INCLUDES)
-libsecp256k1_la_LIBADD = $(SECP_LIBS) $(COMMON_LIB)
+libsecp256k1_la_LIBADD = $(SECP_LIBS) $(COMMON_LIB) $(PRECOMPUTED_LIB)
 libsecp256k1_la_LDFLAGS = -no-undefined
 
 if VALGRIND_ENABLED
@@ -91,10 +100,10 @@ noinst_PROGRAMS += bench bench_internal bench_ecmult
 bench_SOURCES = src/bench.c
 bench_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_LDADD = $(SECP_LIBS) $(COMMON_LIB) $(PRECOMPUTED_LIB)
 bench_internal_CPPFLAGS = $(SECP_INCLUDES)
 bench_ecmult_SOURCES = src/bench_ecmult.c
-bench_ecmult_LDADD = $(SECP_LIBS) $(COMMON_LIB)
+bench_ecmult_LDADD = $(SECP_LIBS) $(COMMON_LIB) $(PRECOMPUTED_LIB)
 bench_ecmult_CPPFLAGS = $(SECP_INCLUDES)
 endif
 
@@ -112,7 +121,7 @@ endif
 if !ENABLE_COVERAGE
 tests_CPPFLAGS += -DVERIFY
 endif
-tests_LDADD = $(SECP_LIBS) $(SECP_TEST_LIBS) $(COMMON_LIB)
+tests_LDADD = $(SECP_LIBS) $(SECP_TEST_LIBS) $(COMMON_LIB) $(PRECOMPUTED_LIB)
 tests_LDFLAGS = -static
 TESTS += tests
 endif
@@ -124,38 +133,38 @@ exhaustive_tests_CPPFLAGS = $(SECP_INCLUDES)
 if !ENABLE_COVERAGE
 exhaustive_tests_CPPFLAGS += -DVERIFY
 endif
+# Note: do not include $(PRECOMPUTED_LIB) in exhaustive_tests (it uses runtime-generated tables).
 exhaustive_tests_LDADD = $(SECP_LIBS) $(COMMON_LIB)
 exhaustive_tests_LDFLAGS = -static
 TESTS += exhaustive_tests
 endif
 
 ### Precomputed tables
-EXTRA_PROGRAMS = gen_ecmult_static_pre_g gen_ecmult_gen_static_prec_table
+EXTRA_PROGRAMS = precompute_ecmult precompute_ecmult_gen
 CLEANFILES = $(EXTRA_PROGRAMS)
 
-gen_ecmult_static_pre_g_SOURCES = src/gen_ecmult_static_pre_g.c
-gen_ecmult_static_pre_g_CPPFLAGS = $(SECP_INCLUDES)
-gen_ecmult_static_pre_g_LDADD = $(SECP_LIBS) $(COMMON_LIB)
+precompute_ecmult_SOURCES = src/precompute_ecmult.c
+precompute_ecmult_CPPFLAGS = $(SECP_INCLUDES)
+precompute_ecmult_LDADD = $(SECP_LIBS) $(COMMON_LIB)
 
-gen_ecmult_gen_static_prec_table_SOURCES = src/gen_ecmult_gen_static_prec_table.c
-gen_ecmult_gen_static_prec_table_CPPFLAGS = $(SECP_INCLUDES)
-gen_ecmult_gen_static_prec_table_LDADD = $(SECP_LIBS) $(COMMON_LIB)
+precompute_ecmult_gen_SOURCES = src/precompute_ecmult_gen.c
+precompute_ecmult_gen_CPPFLAGS = $(SECP_INCLUDES)
+precompute_ecmult_gen_LDADD = $(SECP_LIBS) $(COMMON_LIB)
 
 # See Automake manual, Section "Errors with distclean".
 # We don't list any dependencies for the prebuilt files here because
 # otherwise make's decision whether to rebuild them (even in the first
 # build by a normal user) depends on mtimes, and thus is very fragile.
 # This means that rebuilds of the prebuilt files always need to be
 # forced by deleting them, e.g., by invoking `make clean-precomp`.
-src/ecmult_static_pre_g.h:
-	$(MAKE) $(AM_MAKEFLAGS) gen_ecmult_static_pre_g$(EXEEXT)
-	./gen_ecmult_static_pre_g$(EXEEXT)
-src/ecmult_gen_static_prec_table.h:
-	$(MAKE) $(AM_MAKEFLAGS) gen_ecmult_gen_static_prec_table$(EXEEXT)
-	./gen_ecmult_gen_static_prec_table$(EXEEXT)
-
-PRECOMP = src/ecmult_gen_static_prec_table.h src/ecmult_static_pre_g.h
-noinst_HEADERS += $(PRECOMP)
+src/precomputed_ecmult.c:
+	$(MAKE) $(AM_MAKEFLAGS) precompute_ecmult$(EXEEXT)
+	./precompute_ecmult$(EXEEXT)
+src/precomputed_ecmult_gen.c:
+	$(MAKE) $(AM_MAKEFLAGS) precompute_ecmult_gen$(EXEEXT)
+	./precompute_ecmult_gen$(EXEEXT)
+
+PRECOMP = src/precomputed_ecmult_gen.c src/precomputed_ecmult.c
 precomp: $(PRECOMP)
 
 # Ensure the prebuilt files will be build first (only if they don't exist,

configure.ac

@@ -152,7 +152,7 @@ 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-1) * 64 bytes of data but can be larger in memory due to platform-specific padding and alignment.]
-[A window size larger than 15 will require you delete the prebuilt ecmult_static_pre_g.h file so that it can be rebuilt.]
+[A window size larger than 15 will require you delete the prebuilt precomputed_ecmult.c file so that it can be rebuilt.]
 [For very large window sizes, use "make -j 1" to reduce memory use during compilation.]
 ["auto" is a reasonable setting for desktop machines (currently 15). [default=auto]]
 )],

src/ecmult_compute_table.h

@@ -0,0 +1,16 @@
+/*****************************************************************************************************
+ * Copyright (c) 2013, 2014, 2017, 2021 Pieter Wuille, Andrew Poelstra, Jonas Nick, Russell O'Connor *
+ * Distributed under the MIT software license, see the accompanying                                  *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.                              *
+ *****************************************************************************************************/
+
+#ifndef SECP256K1_ECMULT_COMPUTE_TABLE_H
+#define SECP256K1_ECMULT_COMPUTE_TABLE_H
+
+/* Construct table of all odd multiples of gen in range 1..(2**(window_g-1)-1). */
+static void secp256k1_ecmult_compute_table(secp256k1_ge_storage* table, int window_g, const secp256k1_gej* gen);
+
+/* Like secp256k1_ecmult_compute_table, but one for both gen and gen*2^128. */
+static void secp256k1_ecmult_compute_two_tables(secp256k1_ge_storage* table, secp256k1_ge_storage* table_128, int window_g, const secp256k1_ge* gen);
+
+#endif /* SECP256K1_ECMULT_COMPUTE_TABLE_H */

src/ecmult_compute_table_impl.h

@@ -0,0 +1,49 @@
+/*****************************************************************************************************
+ * Copyright (c) 2013, 2014, 2017, 2021 Pieter Wuille, Andrew Poelstra, Jonas Nick, Russell O'Connor *
+ * Distributed under the MIT software license, see the accompanying                                  *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.                              *
+ *****************************************************************************************************/
+
+#ifndef SECP256K1_ECMULT_COMPUTE_TABLE_IMPL_H
+#define SECP256K1_ECMULT_COMPUTE_TABLE_IMPL_H
+
+#include "ecmult_compute_table.h"
+#include "group_impl.h"
+#include "field_impl.h"
+#include "ecmult.h"
+#include "util.h"
+
+static void secp256k1_ecmult_compute_table(secp256k1_ge_storage* table, int window_g, const secp256k1_gej* gen) {
+    secp256k1_gej gj;
+    secp256k1_ge ge, dgen;
+    int j;
+
+    gj = *gen;
+    secp256k1_ge_set_gej_var(&ge, &gj);
+    secp256k1_ge_to_storage(&table[0], &ge);
+
+    secp256k1_gej_double_var(&gj, gen, NULL);
+    secp256k1_ge_set_gej_var(&dgen, &gj);
+
+    for (j = 1; j < ECMULT_TABLE_SIZE(window_g); ++j) {
+        secp256k1_gej_set_ge(&gj, &ge);
+        secp256k1_gej_add_ge_var(&gj, &gj, &dgen, NULL);
+        secp256k1_ge_set_gej_var(&ge, &gj);
+        secp256k1_ge_to_storage(&table[j], &ge);
+    }
+}
+
+/* Like secp256k1_ecmult_compute_table, but one for both gen and gen*2^128. */
+static void secp256k1_ecmult_compute_two_tables(secp256k1_ge_storage* table, secp256k1_ge_storage* table_128, int window_g, const secp256k1_ge* gen) {
+    secp256k1_gej gj;
+    int i;
+
+    secp256k1_gej_set_ge(&gj, gen);
+    secp256k1_ecmult_compute_table(table, window_g, &gj);
+    for (i = 0; i < 128; ++i) {
+        secp256k1_gej_double_var(&gj, &gj, NULL);
+    }
+    secp256k1_ecmult_compute_table(table_128, window_g, &gj);
+}
+
+#endif /* SECP256K1_ECMULT_COMPUTE_TABLE_IMPL_H */

src/ecmult_gen_prec.h src/ecmult_gen_compute_table.h

@@ -4,11 +4,11 @@
  * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
  ***********************************************************************/
 
-#ifndef SECP256K1_ECMULT_GEN_PREC_H
-#define SECP256K1_ECMULT_GEN_PREC_H
+#ifndef SECP256K1_ECMULT_GEN_COMPUTE_TABLE_H
+#define SECP256K1_ECMULT_GEN_COMPUTE_TABLE_H
 
 #include "ecmult_gen.h"
 
-static void secp256k1_ecmult_gen_create_prec_table(secp256k1_ge_storage* table, const secp256k1_ge* gen, int bits);
+static void secp256k1_ecmult_gen_compute_table(secp256k1_ge_storage* table, const secp256k1_ge* gen, int bits);
 
-#endif /* SECP256K1_ECMULT_GEN_PREC_H */
+#endif /* SECP256K1_ECMULT_GEN_COMPUTE_TABLE_H */

src/ecmult_gen_prec_impl.h src/ecmult_gen_compute_table_impl.h

@@ -4,16 +4,16 @@
  * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
  ***********************************************************************/
 
-#ifndef SECP256K1_ECMULT_GEN_PREC_IMPL_H
-#define SECP256K1_ECMULT_GEN_PREC_IMPL_H
+#ifndef SECP256K1_ECMULT_GEN_COMPUTE_TABLE_IMPL_H
+#define SECP256K1_ECMULT_GEN_COMPUTE_TABLE_IMPL_H
 
-#include "ecmult_gen_prec.h"
+#include "ecmult_gen_compute_table.h"
 #include "group_impl.h"
 #include "field_impl.h"
 #include "ecmult_gen.h"
 #include "util.h"
 
-static void secp256k1_ecmult_gen_create_prec_table(secp256k1_ge_storage* table, const secp256k1_ge* gen, int bits) {
+static void secp256k1_ecmult_gen_compute_table(secp256k1_ge_storage* table, const secp256k1_ge* gen, int bits) {
     int g = ECMULT_GEN_PREC_G(bits);
     int n = ECMULT_GEN_PREC_N(bits);
 
@@ -78,4 +78,4 @@ static void secp256k1_ecmult_gen_create_prec_table(secp256k1_ge_storage* table,
     free(prec);
 }
 
-#endif /* SECP256K1_ECMULT_GEN_PREC_IMPL_H */
+#endif /* SECP256K1_ECMULT_GEN_COMPUTE_TABLE_IMPL_H */

src/ecmult_gen_impl.h

@@ -12,7 +12,7 @@
 #include "group.h"
 #include "ecmult_gen.h"
 #include "hash_impl.h"
-#include "ecmult_gen_static_prec_table.h"
+#include "precomputed_ecmult_gen.h"
 
 static void secp256k1_ecmult_gen_context_build(secp256k1_ecmult_gen_context *ctx) {
     secp256k1_ecmult_gen_blind(ctx, NULL);

src/ecmult_impl.h

@@ -14,7 +14,7 @@
 #include "group.h"
 #include "scalar.h"
 #include "ecmult.h"
-#include "ecmult_static_pre_g.h"
+#include "precomputed_ecmult.h"
 
 #if defined(EXHAUSTIVE_TEST_ORDER)
 /* We need to lower these values for exhaustive tests because
@@ -103,7 +103,7 @@ static void secp256k1_ecmult_odd_multiples_table(int n, secp256k1_gej *prej, sec
  *  It only operates on tables sized for WINDOW_A wnaf multiples.
  *
  *  To compute a*P + b*G, we compute a table for P using this function,
- *  and use the precomputed table in <ecmult_static_pre_g.h> for G.
+ *  and use the precomputed table in <precomputed_ecmult.c> for G.
  */
 static void secp256k1_ecmult_odd_multiples_table_globalz_windowa(secp256k1_ge *pre, secp256k1_fe *globalz, const secp256k1_gej *a) {
     secp256k1_gej prej[ECMULT_TABLE_SIZE(WINDOW_A)];