Print actual String arguments with Xtrace part 1

The changes reflect the feature request #16416. Print the actual string instead of address at max of 32 characters. Subsequent PRs: cmdline option for length (Part 2) and tests (Part 3). Signed-off-by: Nick Kamal <[email protected]>
eclipse-openj9 · Nov 21, 2024 · 4772a09 · 4772a09
1 parent 44766de
commit 4772a09
Showing 1 changed file with 40 additions and 5 deletions.
diff --git a/runtime/rastrace/method_trace.c b/runtime/rastrace/method_trace.c
@@ -474,13 +474,48 @@ traceMethodArgObject(J9VMThread *thr, UDATA* arg0EA, char* cursor, UDATA length)
 	if (object == NULL) {
 		j9str_printf(PORTLIB, cursor, length, "null");
 	} else {
-		J9Class* clazz = J9OBJECT_CLAZZ(thr, object);
-		J9ROMClass * romClass = clazz->romClass;
-		J9UTF8* className = J9ROMCLASS_CLASSNAME(romClass);
+		/* string arg */
+		J9Class *clazz = J9OBJECT_CLAZZ(thr, object);
+		J9JavaVM *vm = thr->javaVM;
+
+		if (clazz == J9VMJAVALANGSTRING_OR_NULL(vm)) {
+
+#define DEFAULT_STRING_LENGTH 32
+
+			char utf8Buffer[128];
+			UDATA utf8Length = 0;
+
+			char *utf8String = vm->internalVMFunctions->copyStringToUTF8WithMemAlloc(
+								thr,
+								object,
+								0,
+								"",
+								0,
+								utf8Buffer,
+								sizeof(utf8Buffer),
+								&utf8Length);
+
+			if (NULL == utf8String) {
+				j9str_printf(PORTLIB, cursor, length, "(String)<Memory allocation error>");
+			} else if (utf8Length > DEFAULT_STRING_LENGTH) {
+				j9str_printf(PORTLIB, cursor, length, "(String)\"%.*s\"...", (U_32)DEFAULT_STRING_LENGTH, utf8String);
+			} else {
+				j9str_printf(PORTLIB, cursor, length, "(String)\"%.*s\"", (U_32)utf8Length, utf8String);
+			}
+
+			if (utf8Buffer != utf8String) {
+				j9mem_free_memory(utf8String);
+			}
 
-		/* TODO: handle arrays */
+#undef DEFAULT_STRING_LENGTH
 
-		j9str_printf(PORTLIB, cursor, length, "%.*s@%p", (U_32)J9UTF8_LENGTH(className), J9UTF8_DATA(className), object);
+		} else {
+			/* TODO: handle arrays */
+
+			J9ROMClass *romClass = clazz->romClass;
+			J9UTF8 *className = J9ROMCLASS_CLASSNAME(romClass);
+			j9str_printf(PORTLIB, cursor, length, "%.*s@%p", (U_32)J9UTF8_LENGTH(className), J9UTF8_DATA(className), object);
+		}
 	}
 }