More fixes for compile-time warnings in equix and hashx

This addresses issue #40800 and a couple other problems I noticed while
trying to reproduce that one.

The original issue is just a missing cast to void* on the args of
__builtin___clear_cache(), and clang is picky about the implicit cast
between what it considers to be char of different signedness. Original
report is from MacOS but it's also reproducible on other clang targets.

The cmake-based original build system for equix and hashx was a handy
way to run tests, but it suffered from some warnings due to incorrect
application of include_directories().

And lastly, there were some return codes from hashx_exec() that get
ignored on equix when asserts are disabled. It bugged me too much to
just silence this with a (void) cast, since even though this is in the
realm of low-likelyhood programming errors and not true runtime errors, I
don't want to make it easy for the hashx_exec() wrappers to return
values that are dangerously wrong if an error is ignored. I made sure
that even if asserts are disabled, we return values that will cause the
solver and verifier to both fail to validate a potential solution.

Signed-off-by: Micah Elizabeth Scott <beth@torproject.org>

changes/ticket40800

@@ -0,0 +1,3 @@
+  o Minor feature (hs):
+    - Fix compiler warnings in equix and hashx when building with clang.
+      Closes ticket 40800.

src/ext/equix/CMakeLists.txt

@@ -24,13 +24,14 @@ if(NOT CMAKE_BUILD_TYPE)
   message(STATUS "Setting default build type: ${CMAKE_BUILD_TYPE}")
 endif()
 
-add_library(equix SHARED ${equix_sources})
-set_property(TARGET equix PROPERTY POSITION_INDEPENDENT_CODE ON)
-set_property(TARGET equix PROPERTY PUBLIC_HEADER include/equix.h)
-include_directories(equix
+include_directories(
   include/
   hashx/include/
   hashx/src/)
+
+add_library(equix SHARED ${equix_sources})
+set_property(TARGET equix PROPERTY POSITION_INDEPENDENT_CODE ON)
+set_property(TARGET equix PROPERTY PUBLIC_HEADER include/equix.h)
 target_compile_definitions(equix PRIVATE HASHX_STATIC)
 target_compile_definitions(equix PRIVATE EQUIX_SHARED)
 target_link_libraries(equix
@@ -43,10 +44,6 @@ set_property(TARGET equix_static PROPERTY POSITION_INDEPENDENT_CODE ON)
 set_target_properties(equix_static PROPERTIES OUTPUT_NAME equix)
 target_compile_definitions(equix_static PRIVATE HASHX_STATIC)
 target_compile_definitions(equix_static PRIVATE EQUIX_STATIC)
-include_directories(equix_static
-  include/
-  hashx/include/
-  hashx/src/)
 target_link_libraries(equix_static
   PRIVATE hashx_static)
 
@@ -58,8 +55,6 @@ install(TARGETS equix equix_static
 
 add_executable(equix-tests
   src/tests.c)
-include_directories(equix-tests
-  include/)
 target_compile_definitions(equix-tests PRIVATE EQUIX_STATIC)
 target_link_libraries(equix-tests
   PRIVATE equix_static)
@@ -73,9 +68,6 @@ add_executable(equix-bench
   src/bench.c
   hashx/src/hashx_thread.c
   hashx/src/hashx_time.c)
-include_directories(equix-bench
-  include/
-  hashx/src/)
 target_compile_definitions(equix-bench PRIVATE EQUIX_STATIC)
 target_link_libraries(equix-bench
   PRIVATE equix_static

src/ext/equix/hashx/CMakeLists.txt

@@ -55,11 +55,11 @@ if(HASHX_SALT)
   endif()
 endif()
 
+include_directories(include/)
+
 add_library(hashx SHARED ${hashx_sources})
 set_property(TARGET hashx PROPERTY POSITION_INDEPENDENT_CODE ON)
 set_property(TARGET hashx PROPERTY PUBLIC_HEADER include/hashx.h)
-include_directories(hashx
-  include/)
 target_compile_definitions(hashx PRIVATE HASHX_SHARED)
 set_target_properties(hashx PROPERTIES VERSION ${HASHX_VERSION_STR}
                                        SOVERSION ${HASHX_VERSION})
@@ -76,8 +76,6 @@ install(TARGETS hashx hashx_static
 
 add_executable(hashx-tests
   src/tests.c)
-include_directories(hashx-tests
-  include/)
 target_compile_definitions(hashx-tests PRIVATE HASHX_STATIC)
 target_link_libraries(hashx-tests
   PRIVATE hashx_static)
@@ -91,8 +89,6 @@ add_executable(hashx-bench
   src/bench.c
   src/hashx_thread.c
   src/hashx_time.c)
-include_directories(hashx-bench
-  include/)
 target_compile_definitions(hashx-bench PRIVATE HASHX_STATIC)
 target_link_libraries(hashx-bench
   PRIVATE hashx_static

src/ext/equix/hashx/src/compiler_a64.c

@@ -149,7 +149,7 @@ bool hashx_compile_a64(const hashx_program* program, uint8_t* code) {
 	if (!hashx_vm_rx(code, COMP_CODE_SIZE))
 		return false;
 #ifdef __GNUC__
-	__builtin___clear_cache(code, pos);
+	__builtin___clear_cache((void*)code, (void*)pos);
 #endif
 	return true;
 }

src/ext/equix/src/equix.c

@@ -28,8 +28,11 @@ static uint64_t sum_pair(hashx_ctx* hash_func, equix_idx left, equix_idx right)
 	uint8_t hash_right[HASHX_SIZE];
 	hashx_result r_left = hashx_exec(hash_func, left, hash_left);
 	hashx_result r_right = hashx_exec(hash_func, right, hash_right);
-	assert(r_left == HASHX_OK && r_right == HASHX_OK);
-	return load64(hash_left) + load64(hash_right);
+	if (r_left == HASHX_OK && r_right == HASHX_OK) {
+		return load64(hash_left) + load64(hash_right);
+	}
+	assert(false);
+	return ~(uint64_t)0;
 }
 
 static equix_result verify_internal(hashx_ctx* hash_func, const equix_solution* solution) {

src/ext/equix/src/solver.c

@@ -47,11 +47,16 @@ typedef stage1_idx_item s1_idx;
 typedef stage2_idx_item s2_idx;
 typedef stage3_idx_item s3_idx;
 
-static FORCE_INLINE uint64_t hash_value(hashx_ctx* hash_func, equix_idx index) {
+static FORCE_INLINE bool hash_value(hashx_ctx* hash_func, equix_idx index, uint64_t *value_out) {
 	char hash[HASHX_SIZE];
 	hashx_result result = hashx_exec(hash_func, index, hash);
-	assert(result == HASHX_OK);
-	return load64(hash);
+	if (result == HASHX_OK) {
+		*value_out = load64(hash);
+		return true;
+	} else {
+		assert(false);
+		return false;
+	}
 }
 
 static void build_solution_stage1(equix_idx* output, solver_heap* heap, s2_idx root) {
@@ -97,7 +102,9 @@ static void build_solution(equix_solution* solution, solver_heap* heap, s3_idx l
 static void solve_stage0(hashx_ctx* hash_func, solver_heap* heap) {
 	CLEAR(heap->stage1_indices.counts);
 	for (u32 i = 0; i < INDEX_SPACE; ++i) {
-		uint64_t value = hash_value(hash_func, i);
+		uint64_t value;
+		if (!hash_value(hash_func, i, &value))
+			break;
 		u32 bucket_idx = value % NUM_COARSE_BUCKETS;
 		u32 item_idx = STAGE1_SIZE(bucket_idx);
 		if (item_idx >= COARSE_BUCKET_ITEMS)