From 014e063a1037302f9d67d0eb03f1fcc6eb668f31 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Sat, 29 Apr 2023 23:09:10 +0100
Subject: [PATCH 1/4] cmake: Add `ProcessConfigurations.cmake` module

---
 CMakeLists.txt                    | 49 ++++--------------
 cmake/ProcessConfigurations.cmake | 86 +++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+), 40 deletions(-)
 create mode 100644 cmake/ProcessConfigurations.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3107eb3bf1..422c505962 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -161,18 +161,17 @@ option(SECP256K1_BUILD_EXHAUSTIVE_TESTS "Build exhaustive tests." ON)
 option(SECP256K1_BUILD_CTIME_TESTS "Build constant-time tests." ${SECP256K1_VALGRIND})
 option(SECP256K1_BUILD_EXAMPLES "Build examples." OFF)
 
+include(ProcessConfigurations)
+set_default_config(RelWithDebInfo)
+
 # Redefine configuration flags.
 # We leave assertions on, because they are only used in the examples, and we want them always on there.
 if(MSVC)
-  string(REGEX REPLACE "/DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELWITHDEBINFO}")
-  string(REGEX REPLACE "/DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
-  string(REGEX REPLACE "/DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_C_FLAGS_MINSIZEREL}")
+  remove_flag_from_all_configs(/DNDEBUG)
 else()
-  string(REGEX REPLACE "-DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELWITHDEBINFO}")
-  string(REGEX REPLACE "-DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
-  string(REGEX REPLACE "-DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_C_FLAGS_MINSIZEREL}")
+  remove_flag_from_all_configs(-DNDEBUG)
   # Prefer -O2 optimization level. (-O3 is CMake's default for Release for many compilers.)
-  string(REGEX REPLACE "-O3[ \t\r\n]*" "-O2" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
+  replace_flag_in_config(Release -O3 -O2)
 endif()
 
 # Define custom "Coverage" build type.
@@ -195,23 +194,10 @@ mark_as_advanced(
 )
 
 get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
-set(default_build_type "RelWithDebInfo")
 if(is_multi_config)
-  set(CMAKE_CONFIGURATION_TYPES "${default_build_type}" "Release" "Debug" "MinSizeRel" "Coverage" CACHE STRING
-    "Supported configuration types."
-    FORCE
-  )
+  list(APPEND CMAKE_CONFIGURATION_TYPES Coverage)
 else()
-  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY
-    STRINGS "${default_build_type}" "Release" "Debug" "MinSizeRel" "Coverage"
-  )
-  if(NOT CMAKE_BUILD_TYPE)
-    message(STATUS "Setting build type to \"${default_build_type}\" as none was specified")
-    set(CMAKE_BUILD_TYPE "${default_build_type}" CACHE STRING
-      "Choose the type of build."
-      FORCE
-    )
-  endif()
+  set_property(CACHE CMAKE_BUILD_TYPE APPEND PROPERTY STRINGS Coverage)
 endif()
 
 include(TryAppendCFlags)
@@ -312,24 +298,7 @@ message("CFLAGS ................................ ${CMAKE_C_FLAGS}")
 get_directory_property(compile_options COMPILE_OPTIONS)
 string(REPLACE ";" " " compile_options "${compile_options}")
 message("Compile options ....................... " ${compile_options})
-if(NOT is_multi_config)
-  message("Build type:")
-  message(" - CMAKE_BUILD_TYPE ................... ${CMAKE_BUILD_TYPE}")
-  string(TOUPPER "${CMAKE_BUILD_TYPE}" build_type)
-  message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_${build_type}}")
-  message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_${build_type}}")
-  message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_${build_type}}")
-else()
-  message("Supported configurations .............. ${CMAKE_CONFIGURATION_TYPES}")
-  message("RelWithDebInfo configuration:")
-  message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_RELWITHDEBINFO}")
-  message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO}")
-  message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO}")
-  message("Debug configuration:")
-  message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_DEBUG}")
-  message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_DEBUG}")
-  message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_DEBUG}")
-endif()
+print_config_flags()
 message("\n")
 if(SECP256K1_EXPERIMENTAL)
   message(
diff --git a/cmake/ProcessConfigurations.cmake b/cmake/ProcessConfigurations.cmake
new file mode 100644
index 0000000000..57f75ec71b
--- /dev/null
+++ b/cmake/ProcessConfigurations.cmake
@@ -0,0 +1,86 @@
+function(get_all_configs output)
+  get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+  if(is_multi_config)
+    set(all_configs ${CMAKE_CONFIGURATION_TYPES})
+  else()
+    get_property(all_configs CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS)
+    if(NOT all_configs)
+      # See https://cmake.org/cmake/help/latest/manual/cmake-buildsystem.7.html#default-and-custom-configurations
+      set(all_configs Debug Release RelWithDebInfo MinSizeRel)
+    endif()
+  endif()
+  set(${output} "${all_configs}" PARENT_SCOPE)
+endfunction()
+
+# When used with multi-configuration generators, this function rearranges
+# the CMAKE_CONFIGURATION_TYPES list, ensuring that the default configuration type
+# appears first while maintaining the order of the remaining configuration types.
+function(set_default_config config)
+  get_all_configs(all_configs)
+  if(NOT ${config} IN_LIST all_configs)
+    message(FATAL_ERROR "The default config is \"${config}\", but must be one of ${all_configs}.")
+  endif()
+
+  list(REMOVE_ITEM all_configs ${config})
+  if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.15)
+    list(PREPEND all_configs ${config})
+  else()
+    set(all_configs ${config} ${all_configs})
+  endif()
+
+  get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+  if(is_multi_config)
+    get_property(help_string CACHE CMAKE_CONFIGURATION_TYPES PROPERTY HELPSTRING)
+    set(CMAKE_CONFIGURATION_TYPES "${all_configs}" CACHE STRING "${help_string}" FORCE)
+  else()
+    set_property(CACHE CMAKE_BUILD_TYPE PROPERTY
+      STRINGS "${all_configs}"
+    )
+    if(NOT CMAKE_BUILD_TYPE)
+      message(STATUS "Setting build type to \"${config}\" as none was specified")
+      get_property(help_string CACHE CMAKE_BUILD_TYPE PROPERTY HELPSTRING)
+      set(CMAKE_BUILD_TYPE "${config}" CACHE STRING "${help_string}" FORCE)
+    endif()
+  endif()
+endfunction()
+
+function(remove_flag_from_all_configs flag)
+  get_all_configs(all_configs)
+  foreach(config IN LISTS all_configs)
+    string(TOUPPER "${config}" config_uppercase)
+    set(flags "${CMAKE_C_FLAGS_${config_uppercase}}")
+    separate_arguments(flags)
+    list(FILTER flags EXCLUDE REGEX "${flag}")
+    list(JOIN flags " " new_flags)
+    set(CMAKE_C_FLAGS_${config_uppercase} "${new_flags}" PARENT_SCOPE)
+  endforeach()
+endfunction()
+
+function(replace_flag_in_config config old_flag new_flag)
+  string(TOUPPER "${config}" config_uppercase)
+  string(REGEX REPLACE "(^| )${old_flag}( |$)" "\\1${new_flag}\\2" new_flags "${CMAKE_C_FLAGS_${config_uppercase}}")
+  set(CMAKE_C_FLAGS_${config_uppercase} "${new_flags}" PARENT_SCOPE)
+endfunction()
+
+function(print_config_flags)
+  macro(print_flags config)
+    string(TOUPPER "${config}" config_uppercase)
+    message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_${config_uppercase}}")
+    message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_${config_uppercase}}")
+    message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_${config_uppercase}}")
+  endmacro()
+
+  get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+  if(is_multi_config)
+    list(JOIN CMAKE_CONFIGURATION_TYPES " " configs)
+    message("Supported configuration types ......... ${configs}")
+    foreach(config IN LISTS CMAKE_CONFIGURATION_TYPES)
+      message("'${config}' configuration type:")
+      print_flags(${config})
+    endforeach()
+  else()
+    message("Build type:")
+    message(" - CMAKE_BUILD_TYPE ................... ${CMAKE_BUILD_TYPE}")
+    print_flags(${CMAKE_BUILD_TYPE})
+  endif()
+endfunction()

From 4b3bd6654051173ef3093ee5f8d47e5c333858bb Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Sat, 29 Apr 2023 23:09:25 +0100
Subject: [PATCH 2/4] cmake: Use `SECP256K1_COVERAGE` instead of
 `CMAKE_BUILD_TYPE=Coverage`

This change fixes coverage-enabled builds for multi-configuration
generators, e.g., "Ninja Multi-Config".
---
 CMakeLists.txt     | 48 +++++++++++++++++-----------------------------
 src/CMakeLists.txt |  4 ++--
 2 files changed, 20 insertions(+), 32 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 422c505962..cacb997827 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -156,9 +156,20 @@ if(SECP256K1_VALGRIND)
 endif()
 
 option(SECP256K1_BUILD_BENCHMARK "Build benchmarks." ON)
+
+include(CMakeDependentOption)
+cmake_dependent_option(SECP256K1_COVERAGE "Enable coverage analysis support." OFF "NOT MSVC" OFF)
+include(TryAppendCFlags)
+if(SECP256K1_COVERAGE)
+  add_compile_definitions(COVERAGE)
+  try_append_c_flags(-O0 --coverage)
+  add_link_options(--coverage)
+endif()
+
 option(SECP256K1_BUILD_TESTS "Build tests." ON)
 option(SECP256K1_BUILD_EXHAUSTIVE_TESTS "Build exhaustive tests." ON)
 option(SECP256K1_BUILD_CTIME_TESTS "Build constant-time tests." ${SECP256K1_VALGRIND})
+
 option(SECP256K1_BUILD_EXAMPLES "Build examples." OFF)
 
 include(ProcessConfigurations)
@@ -170,37 +181,14 @@ if(MSVC)
   remove_flag_from_all_configs(/DNDEBUG)
 else()
   remove_flag_from_all_configs(-DNDEBUG)
-  # Prefer -O2 optimization level. (-O3 is CMake's default for Release for many compilers.)
-  replace_flag_in_config(Release -O3 -O2)
-endif()
-
-# Define custom "Coverage" build type.
-set(CMAKE_C_FLAGS_COVERAGE "${CMAKE_C_FLAGS_RELWITHDEBINFO} -O0 -DCOVERAGE=1 --coverage" CACHE STRING
-  "Flags used by the C compiler during \"Coverage\" builds."
-  FORCE
-)
-set(CMAKE_EXE_LINKER_FLAGS_COVERAGE "${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO} --coverage" CACHE STRING
-  "Flags used for linking binaries during \"Coverage\" builds."
-  FORCE
-)
-set(CMAKE_SHARED_LINKER_FLAGS_COVERAGE "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO} --coverage" CACHE STRING
-  "Flags used by the shared libraries linker during \"Coverage\" builds."
-  FORCE
-)
-mark_as_advanced(
-  CMAKE_C_FLAGS_COVERAGE
-  CMAKE_EXE_LINKER_FLAGS_COVERAGE
-  CMAKE_SHARED_LINKER_FLAGS_COVERAGE
-)
-
-get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
-if(is_multi_config)
-  list(APPEND CMAKE_CONFIGURATION_TYPES Coverage)
-else()
-  set_property(CACHE CMAKE_BUILD_TYPE APPEND PROPERTY STRINGS Coverage)
+  if(SECP256K1_COVERAGE)
+    remove_flag_from_all_configs(-O[s0-9])
+  else()
+    # Prefer -O2 optimization level. (-O3 is CMake's default for Release for many compilers.)
+    replace_flag_in_config(Release -O3 -O2)
+  endif()
 endif()
 
-include(TryAppendCFlags)
 if(MSVC)
   # Keep the following commands ordered lexicographically.
   try_append_c_flags(/W3) # Production quality warning level.
@@ -275,7 +263,7 @@ message("Optional binaries:")
 message("  benchmark ........................... ${SECP256K1_BUILD_BENCHMARK}")
 message("  noverify_tests ...................... ${SECP256K1_BUILD_TESTS}")
 set(tests_status "${SECP256K1_BUILD_TESTS}")
-if(CMAKE_BUILD_TYPE STREQUAL "Coverage")
+if(SECP256K1_COVERAGE)
   set(tests_status OFF)
 endif()
 message("  tests ............................... ${tests_status}")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 0bba19982a..08015eb0d5 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -88,7 +88,7 @@ if(SECP256K1_BUILD_TESTS)
   add_executable(noverify_tests tests.c)
   target_link_libraries(noverify_tests secp256k1_precomputed secp256k1_asm)
   add_test(NAME noverify_tests COMMAND noverify_tests)
-  if(NOT CMAKE_BUILD_TYPE STREQUAL "Coverage")
+  if(NOT SECP256K1_COVERAGE)
     add_executable(tests tests.c)
     target_compile_definitions(tests PRIVATE VERIFY)
     target_link_libraries(tests secp256k1_precomputed secp256k1_asm)
@@ -100,7 +100,7 @@ if(SECP256K1_BUILD_EXHAUSTIVE_TESTS)
   # Note: do not include secp256k1_precomputed in exhaustive_tests (it uses runtime-generated tables).
   add_executable(exhaustive_tests tests_exhaustive.c)
   target_link_libraries(exhaustive_tests secp256k1_asm)
-  target_compile_definitions(exhaustive_tests PRIVATE $<$<NOT:$<CONFIG:Coverage>>:VERIFY>)
+  target_compile_definitions(exhaustive_tests PRIVATE $<$<NOT:$<BOOL:${SECP256K1_COVERAGE}>>:VERIFY>)
   add_test(NAME exhaustive_tests COMMAND exhaustive_tests)
 endif()
 

From 94dd0c0b99a9255378f07d95a57dd55d68ffb22e Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Sat, 29 Apr 2023 23:09:36 +0100
Subject: [PATCH 3/4] autotools, docs: Adjust help string for
 `--enable-coverage` option

---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 82cf95132d..ef954f92da 100644
--- a/configure.ac
+++ b/configure.ac
@@ -151,7 +151,7 @@ AC_ARG_ENABLE(benchmark,
     [SECP_SET_DEFAULT([enable_benchmark], [yes], [yes])])
 
 AC_ARG_ENABLE(coverage,
-    AS_HELP_STRING([--enable-coverage],[enable compiler flags to support kcov coverage analysis [default=no]]), [],
+    AS_HELP_STRING([--enable-coverage],[enable coverage analysis support [default=no]]), [],
     [SECP_SET_DEFAULT([enable_coverage], [no], [no])])
 
 AC_ARG_ENABLE(tests,

From 8eee93dabebbd3671a6046abca0c4af9d9c8772b Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Tue, 4 Jul 2023 21:54:21 +0100
Subject: [PATCH 4/4] Add `doc/build-options.md`

---
 README.md            |   4 +-
 doc/build-options.md | 194 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 196 insertions(+), 2 deletions(-)
 create mode 100644 doc/build-options.md

diff --git a/README.md b/README.md
index 19dabe8505..e0fb7d74c9 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,7 @@ Building with Autotools
     $ make check  # run the test suite
     $ sudo make install  # optional
 
-To compile optional modules (such as Schnorr signatures), you need to run `./configure` with additional flags (such as `--enable-module-schnorrsig`). Run `./configure --help` to see the full list of available flags.
+To configure the build system, run the `./configure` script with additional [options](/doc/build-options.md).
 
 Building with CMake (experimental)
 ----------------------------------
@@ -84,7 +84,7 @@ To maintain a pristine source tree, CMake encourages to perform an out-of-source
     $ make check  # run the test suite
     $ sudo make install  # optional
 
-To compile optional modules (such as Schnorr signatures), you need to run `cmake` with additional flags (such as `-DSECP256K1_ENABLE_MODULE_SCHNORRSIG=ON`). Run `cmake .. -LH` to see the full list of available flags.
+To generate a non-default build system, run the `cmake` command with additional [options](/doc/build-options.md).
 
 ### Cross compiling
 
diff --git a/doc/build-options.md b/doc/build-options.md
new file mode 100644
index 0000000000..e8f66e45e2
--- /dev/null
+++ b/doc/build-options.md
@@ -0,0 +1,194 @@
+# Build Options
+
+This document describes available options when building with:
+- GNU Autotools (hereafter "Autotools")
+- CMake
+- C toolchain only, for instance, GNU C compiler and GNU Binutils (hereafter "Manual")
+
+Autotools options must be provided to the `./configure` script.
+
+CMake options must be provided to the `cmake` when generating a buildsystem.
+
+In manual builds, options are just compiler flags.
+
+## Library Type
+
+By default, when using Autotools, both the shared and static libsecp256k1 libraries are built.
+However, when using CMake, only one type of the library is built (see [PR1230](https://github.com/bitcoin-core/secp256k1/pull/1230)).
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-shared=yes` | `yes`, `no` |
+| Autotools | `--enable-static=yes` | `yes`, `no` |
+| CMake | `-DBUILD_SHARED_LIBS=ON` | `ON`, `OFF` |
+| CMake | `-DSECP256K1_DISABLE_SHARED=OFF` | `ON`, `OFF` |
+
+## Optional Modules
+
+### ECDH Module
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-module-ecdh=yes` | `yes`, `no` |
+| CMake | `-DSECP256K1_ENABLE_MODULE_ECDH=ON` | `ON`, `OFF` |
+| Manual | n/a | `-DENABLE_MODULE_ECDH=1` |
+
+### ECDSA Pubkey Recovery Module
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-module-recovery=no` | `yes`, `no` |
+| CMake | `-DSECP256K1_ENABLE_MODULE_RECOVERY=OFF` | `ON`, `OFF` |
+| Manual | n/a | `-DENABLE_MODULE_RECOVERY=1` |
+
+### Extrakeys Module
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-module-extrakeys=yes` | `yes`, `no` |
+| CMake | `-DSECP256K1_ENABLE_MODULE_EXTRAKEYS=ON` | `ON`, `OFF` |
+| Manual | n/a | `-DENABLE_MODULE_EXTRAKEYS=1` |
+
+### Schnorrsig Module
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-module-extrakeys=yes` | `yes`, `no` |
+| CMake | `-DSECP256K1_ENABLE_MODULE_SCHNORRSIG=ON` | `ON`, `OFF` |
+| Manual | n/a | `-DENABLE_MODULE_SCHNORRSIG=1` |
+
+### ElligatorSwift Module
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-module-ellswift=yes` | `yes`, `no` |
+| CMake | `-DSECP256K1_ENABLE_MODULE_ELLSWIFT=ON` | `ON`, `OFF` |
+| Manual | n/a | `-DENABLE_MODULE_ELLSWIFT=1` |
+
+## Precomputed Table Parameters
+
+### Window Size
+
+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 `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`/`AUTO` is a reasonable setting for desktop machines (currently 15).
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--with-ecmult-window=auto` | `auto`, [`2`..`24`] |
+| CMake | `-DSECP256K1_ECMULT_WINDOW_SIZE=AUTO` | `AUTO`, [`2`..`24`] |
+| Manual | `-DECMULT_WINDOW_SIZE=15` | [`2`..`24`] |
+
+### Precision Bits
+
+Precision bits to tune the precomputed table size for signing.
+The size of the table is 32kB for 2 bits, 64kB for 4 bits, 512kB for 8 bits of precision.
+A larger table size usually results in possible faster signing.
+`auto`/`AUTO` is a reasonable setting for desktop machines (currently 4).
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--with-ecmult-gen-precision=auto` | `auto`, `2`, `4`, `8` |
+| CMake | `-DSECP256K1_ECMULT_GEN_PREC_BITS=AUTO` | `AUTO`, `2`, `4`, `8` |
+| Manual | `-DECMULT_GEN_PREC_BITS=4` | `2`, `4`, `8` |
+
+## Optional Features
+
+### Assembly Optimization
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--with-asm=auto` | `auto`, `no`, `x86_64`, `arm32` |
+| CMake | `-DSECP256K1_ASM=AUTO` | `AUTO`, `OFF`, `x86_64`, `arm32` |
+| Manual | n/a | `-DUSE_ASM_X86_64=1`, `-DUSE_EXTERNAL_ASM=1` |
+
+`arm32` assembly optimization is an [experimental](#experimental-options) option.
+
+### External Default Callback Functions
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-external-default-callbacks=no` | `yes`, `no` |
+| CMake | `-DSECP256K1_USE_EXTERNAL_DEFAULT_CALLBACKS=OFF` | `ON`, `OFF` |
+| Manual | n/a | `-DUSE_EXTERNAL_DEFAULT_CALLBACKS=1` |
+
+For more details, see docs in [`secp256k1.h`](/include/secp256k1.h).
+
+### Wide Multiplication Implementation
+
+This is a _test-only_ override of the "widemul" setting.
+Legal values are:
+- `int64` (for `[u]int64_t`)
+- `int128` (for `[unsigned] __int128`)
+- `int128_struct` (for `int128` implemented as a structure)
+- `auto`/`AUTO` (for autodetection by the C code)
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--with-test-override-wide-multiply=auto` | `auto`, `int64`, `int128`, `int128_struct` |
+| CMake | `-DSECP256K1_TEST_OVERRIDE_WIDE_MULTIPLY=AUTO` | `AUTO`, `int64`, `int128`, `int128_struct` |
+| Manual | n/a | `-DUSE_FORCE_WIDEMUL_INT64=1`, `-DUSE_FORCE_WIDEMUL_INT128=1`, `-DUSE_FORCE_WIDEMUL_INT128_STRUCT=1` |
+
+## Experimental Options
+
+To use experimental options, they must be allowed explicitly.
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-experimental=no` | `yes`, `no` |
+| CMake | `-DSECP256K1_EXPERIMENTAL=OFF` | `ON`, `OFF` |
+
+## Optional Binaries
+
+### Benchmarks
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-benchmark=yes` | `yes`, `no` |
+| CMake | `-DSECP256K1_BUILD_BENCHMARK=ON` | `ON`, `OFF` |
+
+For more details, see docs in [README](/README.md#benchmark).
+
+### Tests
+
+#### Tests with and without `VERIFY` mode
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-tests=yes` | `yes`, `no` |
+| CMake | `-DSECP256K1_BUILD_TESTS=ON` | `ON`, `OFF` |
+
+#### Exhaustive Tests
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-exhaustive-tests=yes` | `yes`, `no` |
+| CMake | `-DSECP256K1_BUILD_EXHAUSTIVE_TESTS=ON` | `ON`, `OFF` |
+
+#### Constant-time Tests
+
+To build this tool, a memory-checking interface is required: [Valgrind](#build-with-valgrind) or MSan.
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-ctime-tests=yes` if Valgrind enabled | `yes`, `no` |
+| CMake | `-DSECP256K1_BUILD_CTIME_TESTS=ON` if Valgrind enabled | `ON`, `OFF` |
+
+##### Build with Valgrind
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--with-valgrind=auto` | `auto`, `yes`, `no` |
+| CMake | `-DSECP256K1_VALGRIND=AUTO` | `AUTO`, `ON`, `OFF` |
+
+#### Coverage Analysis Support
+
+|   | Option with the default value | Available option values |
+|---|-------------------------------|-------------------------|
+| Autotools | `--enable-coverage=no` | `yes`, `no` |
+| CMake | `-DSECP256K1_COVERAGE=OFF` | `ON`, `OFF` |
+
+For more details, see docs in [README](/README.md#test-coverage).