Split Abort definition from targets.cc

This allows compilation without the dynamic dispatch machinery and gives
an example of the interface for the `Abort` function should you wish to
write your own.

BUILD

@@ -156,6 +156,7 @@ COMPAT = [
 cc_library(
     name = "hwy",
     srcs = [
+        "hwy/abort.cc",
         "hwy/aligned_allocator.cc",
         "hwy/per_target.cc",
         "hwy/print.cc",

CMakeLists.txt

@@ -1,4 +1,7 @@
 # Copyright 2019 Google LLC
+# Copyright 2024 Arm Limited and/or its affiliates <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-License-Identifier: BSD-3-Clause
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -132,6 +135,7 @@ list(APPEND HWY_CONTRIB_SOURCES
 endif()  # HWY_ENABLE_CONTRIB
 
 set(HWY_SOURCES
+    hwy/abort.cc
     hwy/aligned_allocator.cc
     hwy/aligned_allocator.h
     hwy/base.h

hwy/abort.cc

@@ -0,0 +1,40 @@
+// Copyright 2019 Google LLC
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-License-Identifier: BSD-3-Clause
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "hwy/base.h"
+
+namespace hwy {
+
+HWY_DLLEXPORT HWY_NORETURN void HWY_FORMAT(3, 4)
+    Abort(const char* file, int line, const char* format, ...) {
+  char buf[800];
+  va_list args;
+  va_start(args, format);
+  vsnprintf(buf, sizeof(buf), format, args);
+  va_end(args);
+
+  fprintf(stderr, "Abort at %s:%d: %s\n", file, line, buf);
+
+// If compiled with any sanitizer, they can also print a stack trace.
+#if HWY_IS_ASAN || HWY_IS_MSAN || HWY_IS_TSAN
+  __sanitizer_print_stack_trace();
+#endif  // HWY_IS_*
+  fflush(stderr);
+
+// Now terminate the program:
+#if HWY_ARCH_RVV
+  exit(1);  // trap/abort just freeze Spike.
+#elif HWY_IS_DEBUG_BUILD && !HWY_COMPILER_MSVC
+  // Facilitates breaking into a debugger, but don't use this in non-debug
+  // builds because it looks like "illegal instruction", which is misleading.
+  __builtin_trap();
+#else
+  abort();  // Compile error without this due to HWY_NORETURN.
+#endif
+}
+}

hwy/targets.cc

@@ -15,10 +15,8 @@
 
 #include "hwy/targets.h"
 
-#include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <stdlib.h>  // abort / exit
 
 #include "hwy/detect_targets.h"
 #include "hwy/highway.h"
@@ -545,34 +543,6 @@ int64_t DetectTargets() {
 
 }  // namespace
 
-HWY_DLLEXPORT HWY_NORETURN void HWY_FORMAT(3, 4)
-    Abort(const char* file, int line, const char* format, ...) {
-  char buf[800];
-  va_list args;
-  va_start(args, format);
-  vsnprintf(buf, sizeof(buf), format, args);
-  va_end(args);
-
-  fprintf(stderr, "Abort at %s:%d: %s\n", file, line, buf);
-
-// If compiled with any sanitizer, they can also print a stack trace.
-#if HWY_IS_ASAN || HWY_IS_MSAN || HWY_IS_TSAN
-  __sanitizer_print_stack_trace();
-#endif  // HWY_IS_*
-  fflush(stderr);
-
-// Now terminate the program:
-#if HWY_ARCH_RVV
-  exit(1);  // trap/abort just freeze Spike.
-#elif HWY_IS_DEBUG_BUILD && !HWY_COMPILER_MSVC
-  // Facilitates breaking into a debugger, but don't use this in non-debug
-  // builds because it looks like "illegal instruction", which is misleading.
-  __builtin_trap();
-#else
-  abort();  // Compile error without this due to HWY_NORETURN.
-#endif
-}
-
 HWY_DLLEXPORT void DisableTargets(int64_t disabled_targets) {
   supported_mask_ = static_cast<int64_t>(~disabled_targets);
   // This will take effect on the next call to SupportedTargets, which is