cmake: Add check_arm32_assembly function

bitcoin-core · May 11, 2023 · 64f1449 · 64f1449
1 parent e5cf4bf
commit 64f1449
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Showing 3 changed files with 25 additions and 1 deletion.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -107,7 +107,13 @@ set_property(CACHE SECP256K1_ASM PROPERTY STRINGS "AUTO" "OFF" "x86_64" "arm32")
 check_string_option_value(SECP256K1_ASM)
 if(SECP256K1_ASM STREQUAL "arm32")
   enable_language(ASM)
-  add_compile_definitions(USE_EXTERNAL_ASM=1)
+  include(CheckArm32Assembly)
+  check_arm32_assembly()
+  if(HAVE_ARM32_ASM)
+    add_compile_definitions(USE_EXTERNAL_ASM=1)
+  else()
+    message(FATAL_ERROR "ARM32 assembly optimization requested but not available.")
+  endif()
 elseif(SECP256K1_ASM)
   include(Check64bitAssembly)
   check_64bit_assembly()

diff --git a/cmake/CheckArm32Assembly.cmake b/cmake/CheckArm32Assembly.cmake
@@ -0,0 +1,9 @@
+function(check_arm32_assembly)
+  # This avoids running a linker.
+  set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+
+  try_compile(HAVE_ARM32_ASM
+    ${CMAKE_BINARY_DIR}/check_arm32_assembly
+    SOURCES ${CMAKE_SOURCE_DIR}/cmake/source_arm32.s
+  )
+endfunction()
diff --git a/cmake/source_arm32.s b/cmake/source_arm32.s
@@ -0,0 +1,9 @@
+.syntax unified
+.eabi_attribute 24, 1
+.eabi_attribute 25, 1
+.text
+.global	test_function
+.type	test_function, %function
+test_function:
+	ldr	r0, =0x002A
+	bx	lr