build: Level up MSVC warnings

Author: hebasto

CMakeLists.txt

@@ -212,8 +212,10 @@ endif()
 include(TryAppendCFlags)
 if(MSVC)
   # Keep the following commands ordered lexicographically.
-  try_append_c_flags(/W2) # Moderate warning level.
+  try_append_c_flags(/W3) # Production quality warning level.
   try_append_c_flags(/wd4146) # Disable warning C4146 "unary minus operator applied to unsigned type, result still unsigned".
+  try_append_c_flags(/wd4244) # Disable warning C4244 "'conversion' conversion from 'type1' to 'type2', possible loss of data".
+  try_append_c_flags(/wd4267) # Disable warning C4267 "'var' : conversion from 'size_t' to 'type', possible loss of data".
 else()
   # Keep the following commands ordered lexicographically.
   try_append_c_flags(-pedantic)

configure.ac

@@ -121,7 +121,12 @@ AC_DEFUN([SECP_TRY_APPEND_DEFAULT_CFLAGS], [
     # libtool makes the same assumption internally.
     # Note that "/opt" and "-opt" are equivalent for MSVC; we use "-opt" because "/opt" looks like a path.
     if test x"$GCC" != x"yes" && test x"$build_windows" = x"yes"; then
-      SECP_TRY_APPEND_CFLAGS([-W2 -wd4146], $1) # Moderate warning level, disable warning C4146 "unary minus operator applied to unsigned type, result still unsigned"
+      SECP_TRY_APPEND_CFLAGS([-W3], $1) # Production quality warning level.
+      SECP_TRY_APPEND_CFLAGS([-wd4146], $1) # Disable warning C4146 "unary minus operator applied to unsigned type, result still unsigned".
+      SECP_TRY_APPEND_CFLAGS([-wd4244], $1) # Disable warning C4244 "'conversion' conversion from 'type1' to 'type2', possible loss of data".
+      SECP_TRY_APPEND_CFLAGS([-wd4267], $1) # Disable warning C4267 "'var' : conversion from 'size_t' to 'type', possible loss of data".
+      # The following warning is relevant to benchmarks and tests only.
+      SECP_TRY_APPEND_CFLAGS([-wd4996], $1) # Disable warning C4996 for the usage of a function, class member, variable, or typedef that's marked deprecated.
       # We pass -ignore:4217 to the MSVC linker to suppress warning 4217 when
       # importing variables from a statically linked secp256k1.
       # (See the libtool manual, section "Windows DLLs" for background.)

src/CMakeLists.txt

@@ -75,31 +75,37 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "Windows")
 endif()
 unset(${PROJECT_NAME}_soversion)
 
+add_library(secp256k1_warning_suppression INTERFACE)
+target_compile_options(secp256k1_warning_suppression INTERFACE
+  # Disable warning C4996 for the usage of a function, class member, variable, or typedef that's marked deprecated.
+  $<$<C_COMPILER_ID:MSVC>:/wd4996>
+)
+
 if(SECP256K1_BUILD_BENCHMARK)
   add_executable(bench bench.c)
-  target_link_libraries(bench secp256k1)
+  target_link_libraries(bench secp256k1 secp256k1_warning_suppression)
   add_executable(bench_internal bench_internal.c)
-  target_link_libraries(bench_internal secp256k1_precomputed secp256k1_asm)
+  target_link_libraries(bench_internal secp256k1_precomputed secp256k1_asm secp256k1_warning_suppression)
   add_executable(bench_ecmult bench_ecmult.c)
-  target_link_libraries(bench_ecmult secp256k1_precomputed secp256k1_asm)
+  target_link_libraries(bench_ecmult secp256k1_precomputed secp256k1_asm secp256k1_warning_suppression)
 endif()
 
 if(SECP256K1_BUILD_TESTS)
   add_executable(noverify_tests tests.c)
-  target_link_libraries(noverify_tests secp256k1_precomputed secp256k1_asm)
+  target_link_libraries(noverify_tests secp256k1_precomputed secp256k1_asm secp256k1_warning_suppression)
   add_test(NAME noverify_tests COMMAND noverify_tests)
   if(NOT CMAKE_BUILD_TYPE STREQUAL "Coverage")
     add_executable(tests tests.c)
     target_compile_definitions(tests PRIVATE VERIFY)
-    target_link_libraries(tests secp256k1_precomputed secp256k1_asm)
+    target_link_libraries(tests secp256k1_precomputed secp256k1_asm secp256k1_warning_suppression)
     add_test(NAME tests COMMAND tests)
   endif()
 endif()
 
 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_link_libraries(exhaustive_tests secp256k1_asm secp256k1_warning_suppression)
   target_compile_definitions(exhaustive_tests PRIVATE $<$<NOT:$<CONFIG:Coverage>>:VERIFY>)
   add_test(NAME exhaustive_tests COMMAND exhaustive_tests)
 endif()