cmake: Add option to recreate precomputed files

.github/workflows/ci.yml

@@ -556,7 +556,13 @@ jobs:
       - *CHECKOUT
 
       - name: Generate buildsystem
-        run: cmake -E env CFLAGS="/WX ${{ matrix.configuration.cpp_flags }}" cmake -B build -DSECP256K1_ENABLE_MODULE_RECOVERY=ON -DSECP256K1_BUILD_EXAMPLES=ON ${{ matrix.configuration.cmake_options }}
+        run: |
+          cmake -E env CFLAGS="/WX ${{ matrix.configuration.cpp_flags }}" `
+          cmake -B build `
+            -DSECP256K1_BUILD_PRECOMPUTED=ON `
+            -DSECP256K1_ENABLE_MODULE_RECOVERY=ON `
+            -DSECP256K1_BUILD_EXAMPLES=ON `
+            ${{ matrix.configuration.cmake_options }}
 
       - name: Build
         run: cmake --build build --config RelWithDebInfo -- /p:UseMultiToolTask=true /maxCpuCount

CMakeLists.txt

@@ -141,6 +141,8 @@ 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)
 
+option(SECP256K1_BUILD_PRECOMPUTED "Recreate the precomputed files." OFF)
+
 # Redefine configuration flags.
 # We leave assertions on, because they are only used in the examples, and we want them always on there.
 if(MSVC)

CMakePresets.json

@@ -7,7 +7,8 @@
       "cacheVariables": {
         "SECP256K1_EXPERIMENTAL": "ON",
         "SECP256K1_ENABLE_MODULE_RECOVERY": "ON",
-        "SECP256K1_BUILD_EXAMPLES": "ON"
+        "SECP256K1_BUILD_EXAMPLES": "ON",
+        "SECP256K1_BUILD_PRECOMPUTED": "ON"
       },
       "warnings": {
         "dev": true,

cmake/Precompute.cmake

@@ -0,0 +1,13 @@
+function(precompute base_name)
+  add_executable(secp256k1_precompute_${base_name} EXCLUDE_FROM_ALL precompute_${base_name}.c)
+  set_target_properties(secp256k1_precompute_${base_name} PROPERTIES
+    COMPILE_DEFINITIONS VERIFY
+    RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}
+  )
+  add_custom_command(
+    OUTPUT ${PROJECT_BINARY_DIR}/src/precomputed_${base_name}.c
+    COMMAND secp256k1_precompute_${base_name}
+    DEPENDS secp256k1_precompute_${base_name}
+    WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
+  )
+endfunction()

src/CMakeLists.txt

@@ -45,10 +45,22 @@ if(SECP256K1_ENABLE_MODULE_ECDH)
   set_property(TARGET secp256k1 APPEND PROPERTY PUBLIC_HEADER ${PROJECT_SOURCE_DIR}/include/secp256k1_ecdh.h)
 endif()
 
-add_library(secp256k1_precomputed OBJECT EXCLUDE_FROM_ALL
-  precomputed_ecmult.c
-  precomputed_ecmult_gen.c
-)
+add_library(secp256k1_precomputed OBJECT EXCLUDE_FROM_ALL)
+if(SECP256K1_BUILD_PRECOMPUTED)
+  include(Precompute)
+  precompute(ecmult)
+  precompute(ecmult_gen)
+  target_sources(secp256k1_precomputed PRIVATE
+    ${PROJECT_BINARY_DIR}/src/precomputed_ecmult.c
+    ${PROJECT_BINARY_DIR}/src/precomputed_ecmult_gen.c
+  )
+  target_include_directories(secp256k1_precomputed PRIVATE ${CMAKE_CURRENT_LIST_DIR})
+else()
+  target_sources(secp256k1_precomputed PRIVATE
+    ${CMAKE_CURRENT_LIST_DIR}/precomputed_ecmult.c
+    ${CMAKE_CURRENT_LIST_DIR}/precomputed_ecmult_gen.c
+  )
+endif()
 
 # Add objects explicitly rather than linking to the object libs to keep them
 # from being exported.