WIP: Reduce jmethodID

build-logic/conventions/src/main/kotlin/com/datadoghq/native/config/ConfigurationPresets.kt

@@ -186,25 +186,47 @@ object ConfigurationPresets {
             Platform.LINUX -> {
                 config.compilerArgs.set(asanCompilerArgs + commonLinuxCompilerArgs(version))
 
-                val libasan = PlatformUtils.locateLibasan(compiler)
-                val asanLinkerArgs = if (libasan != null) {
-                    listOf(
-                        "-L${File(libasan).parent}",
-                        "-lasan",
-                        "-lubsan",
+                val isClang = PlatformUtils.isClangCompiler(compiler)
+                val ldPreloadLib: String?
+                val baseLinkerArgs: List<String>
+                val asanLinkerArgs: List<String>
+
+                if (isClang) {
+                    // With clang, ASan/UBSan symbols in the shared library are resolved at runtime
+                    // by the full LLVM runtime (libclang_rt.asan-x86_64.so) loaded via LD_PRELOAD.
+                    // At link time, clang adds only asan_static stubs (weak trampolines without strong
+                    // definitions), so -Wl,-z,defs must be omitted — it would fail on unresolved
+                    // ASan/UBSan symbols. Explicitly linking GCC's -lasan/-lubsan is also wrong:
+                    // GCC's libubsan lacks LLVM-specific symbols (e.g. __ubsan_handle_function_type_mismatch_abort).
+                    ldPreloadLib = PlatformUtils.locateClangRtAsan(compiler)
+                    baseLinkerArgs = commonLinuxLinkerArgs().filter { it != "-Wl,-z,defs" }
+                    asanLinkerArgs = listOf(
                         "-fsanitize=address",
                         "-fsanitize=undefined",
                         "-fno-omit-frame-pointer"
                     )
                 } else {
-                    emptyList()
+                    ldPreloadLib = PlatformUtils.locateLibasan(compiler)
+                    baseLinkerArgs = commonLinuxLinkerArgs()
+                    asanLinkerArgs = if (ldPreloadLib != null) {
+                        listOf(
+                            "-L${File(ldPreloadLib).parent}",
+                            "-lasan",
+                            "-lubsan",
+                            "-fsanitize=address",
+                            "-fsanitize=undefined",
+                            "-fno-omit-frame-pointer"
+                        )
+                    } else {
+                        emptyList()
+                    }
                 }
 
-                config.linkerArgs.set(commonLinuxLinkerArgs() + asanLinkerArgs)
+                config.linkerArgs.set(baseLinkerArgs + asanLinkerArgs)
 
-                if (libasan != null) {
+                if (ldPreloadLib != null) {
                     config.testEnvironment.apply {
-                        put("LD_PRELOAD", libasan)
+                        put("LD_PRELOAD", ldPreloadLib)
                         put("ASAN_OPTIONS", "allocator_may_return_null=1:unwind_abort_on_malloc=1:use_sigaltstack=0:detect_stack_use_after_return=0:handle_segv=0:halt_on_error=0:abort_on_error=0:print_stacktrace=1:symbolize=1:log_path=/tmp/asan_%p.log:suppressions=$rootDir/gradle/sanitizers/asan.supp")
                         put("UBSAN_OPTIONS", "halt_on_error=0:abort_on_error=0:print_stacktrace=1:log_path=/tmp/ubsan_%p.log:suppressions=$rootDir/gradle/sanitizers/ubsan.supp")
                         put("LSAN_OPTIONS", "detect_leaks=0")

build-logic/conventions/src/main/kotlin/com/datadoghq/native/util/PlatformUtils.kt

@@ -129,6 +129,33 @@ object PlatformUtils {
 
     fun locateLibtsan(compiler: String = "gcc"): String? = locateLibrary("libtsan", compiler)
 
+    fun isClangCompiler(compiler: String): Boolean {
+        return File(compiler).name.startsWith("clang")
+    }
+
+    /**
+     * Locate LLVM's ASan shared library (libclang_rt.asan-*.so) for use with clang.
+     * Returns null if the compiler is not clang or the library cannot be found.
+     * This library contains both ASan and UBSan symbols needed for LD_PRELOAD.
+     */
+    fun locateClangRtAsan(compiler: String): String? {
+        if (!isClangCompiler(compiler)) return null
+        return try {
+            val process = ProcessBuilder(compiler, "--print-resource-dir")
+                .redirectErrorStream(true)
+                .start()
+            val resourceDir = process.inputStream.bufferedReader().readText().trim()
+            process.waitFor()
+            if (process.exitValue() != 0) return null
+
+            File("$resourceDir/lib/linux").listFiles()
+                ?.firstOrNull { it.name.matches(Regex("libclang_rt\\.asan-.*\\.so")) }
+                ?.absolutePath
+        } catch (e: Exception) {
+            null
+        }
+    }
+
     fun checkFuzzerSupport(): Boolean {
         return try {
             val testFile = createTempFile("fuzzer_check", ".cpp")
@@ -155,7 +182,12 @@ object PlatformUtils {
     }
 
     fun hasAsan(compiler: String = "gcc"): Boolean {
-        return !isMusl() && locateLibasan(compiler) != null
+        if (isMusl()) return false
+        return if (isClangCompiler(compiler)) {
+            locateClangRtAsan(compiler) != null
+        } else {
+            locateLibasan(compiler) != null
+        }
     }
 
     fun hasTsan(compiler: String = "gcc"): Boolean {