feat: add rocbuild_link_as_needed()

rocbuild.cmake

@@ -1,10 +1,11 @@
 # Author: Zhuo Zhang <[email protected]>
 # Homepage: https://github.com/zchrissirhcz/rocbuild
 
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.13)
 
 # CMake 3.10: include_guard()
 # CMake 3.21: $<TARGET_RUNTIME_DLLS:tgt>
+# CMake 3.13: target_link_options() use "LINKER:" as a portable way for different compiler + linker combo
 
 include_guard()
 
@@ -268,5 +269,19 @@ function(rocbuild_hide_symbols TARGET)
 endfunction()
 
 
+function(rocbuild_link_as_needed TARGET)
+  get_target_property(TARGET_TYPE ${TARGET} TYPE)
+  if(TARGET_TYPE STREQUAL "SHARED_LIBRARY")  
+    if((CMAKE_C_COMPILER_ID MATCHES "^(GNU|Clang)$") OR
+       (CMAKE_CXX_COMPILER_ID MATCHES "^(GNU|Clang)$"))
+      target_link_options(${TARGET} PRIVATE "LINKER:-as-needed")
+    elseif((CMAKE_C_COMPILER_ID STREQUAL "AppleClang") OR
+           (CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang"))
+      target_link_options(${TARGET} PRIVATE "LINKER:-dead_strip_dylibs")
+    endif()
+  endif()
+endfunction()
+
+
 rocbuild_set_artifacts_path()
 rocbuild_enable_ninja_colorful_output()

test.py

@@ -222,5 +222,43 @@ def test_copy_dlls(self):
             self.assertTrue(items[3] == 'test.exe')
             shutil.rmtree('build/copy_dlls')
 
+    def test_link_as_needed(self):
+        if os_name == 'linux':
+            self.check_generate('link_as_needed', args='-DLINK_AS_NEEDED=0')
+            self.check_build('link_as_needed')
+            cmd = 'ldd build/link_as_needed/libfoo_math.so'
+            ret, out = check_output(cmd)
+            print(out)
+            self.assertEqual(0, ret, out)
+            self.assertIn('libqux.so =>', out)
+            shutil.rmtree('build/link_as_needed')
+
+            self.check_generate('link_as_needed', args='-DLINK_AS_NEEDED=1')
+            self.check_build('link_as_needed')
+            cmd = 'ldd build/link_as_needed/libfoo_math.so'
+            ret, out = check_output(cmd)
+            print(out)
+            self.assertEqual(0, ret, out)
+            self.assertTrue('libqux.so =>' not in out)
+            shutil.rmtree('build/link_as_needed')
+        elif os_name == 'mac':
+            self.check_generate('link_as_needed', args='-DLINK_AS_NEEDED=0')
+            self.check_build('link_as_needed')
+            cmd = 'otool -L build/link_as_needed/libfoo_math.dylib'
+            ret, out = check_output(cmd)
+            print(out)
+            self.assertEqual(0, ret, out)
+            self.assertIn('@rpath/libqux.dylib', out)
+            shutil.rmtree('build/link_as_needed')
+
+            self.check_generate('link_as_needed', args='-DLINK_AS_NEEDED=1')
+            self.check_build('link_as_needed')
+            cmd = 'otool -L build/link_as_needed/libfoo_math.dylib'
+            ret, out = check_output(cmd)
+            print(out)
+            self.assertEqual(0, ret, out)
+            self.assertTrue('@rpath/libqux.dylib' not in out)
+            shutil.rmtree('build/link_as_needed')
+
 if __name__ == "__main__":
     unittest.main()

tests/link_as_needed/CMakeLists.txt

@@ -0,0 +1,25 @@
+cmake_minimum_required(VERSION 3.10)
+project(test_link_as_needed)
+
+include(../../rocbuild.cmake)
+
+# For test purpose, we explicitly enable `--no-as-needed` for GNU and Clang as the default behavior.
+if(CMAKE_C_COMPILER_ID MATCHES "^(GNU|Clang)$")
+  add_link_options("LINKER:--no-as-needed")
+endif()
+
+add_library(foo_math SHARED
+  foo_math.h
+  foo_math.c
+)
+target_include_directories(foo_math PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_compile_definitions(foo_math PRIVATE FOO_MATH_EXPORTS)
+
+add_library(foo SHARED ../src/foo.c)
+target_include_directories(foo PRIVATE ../src)
+
+target_link_libraries(foo_math PRIVATE foo)
+
+if(LINK_AS_NEEDED)
+  rocbuild_link_as_needed(foo_math)
+endif()

tests/link_as_needed/foo_math.c

@@ -0,0 +1,21 @@
+#include "foo_math.h"
+#include <stdlib.h>
+
+static int compare(const void *a, const void *b)
+{
+    int int_a = *(int *)a;
+    int int_b = *(int *)b;
+
+    if (int_a < int_b) return -1;
+    else if (int_a > int_b) return 1;
+    else return 0;
+}
+
+void abs_sort(int n, int* data)
+{
+    for (int i = 0; i < n; i++)
+    {
+        data[i] = abs(i);
+    }
+    qsort(data, n, sizeof(int), compare);
+}

tests/link_as_needed/foo_math.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#ifdef FOO_MATH_EXPORTS
+#   if defined(_MSC_VER) || defined(__CYGWIN__) || defined(__MINGW32__)
+#       define FOO_MATH_API __declspec(dllexport)
+#   elif defined(__GNUC__) && __GNUC__ >= 4
+#       define FOO_MATH_API __attribute__ ((visibility ("default")))
+#   endif
+#else
+#   if defined(_MSC_VER) || defined(__CYGWIN__) || defined(__MINGW32__)
+#       define FOO_MATH_API __declspec(dllimport)
+#   else
+#       define FOO_MATH_API
+#   endif
+#endif
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+FOO_MATH_API
+void abs_sort(int n, int* data);
+
+#ifdef __cplusplus
+}
+#endif
+