[PATCH 1/9] perf/jit: improve error messages from JVMTI

From: Stephane Eranian
Date: Thu Oct 13 2016 - 07:02:22 EST


This patch improves the usefulness of error messages
generated by the JVMTI interfac.e This can help identify
the root cause of a problem by printing the actual error
code. The patch adds a new helper function called print_error().

Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
---
tools/perf/jvmti/libjvmti.c | 37 +++++++++++++++++++++++++++----------
1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/tools/perf/jvmti/libjvmti.c b/tools/perf/jvmti/libjvmti.c
index ac12e4b91a92..2d9bc04b79a8 100644
--- a/tools/perf/jvmti/libjvmti.c
+++ b/tools/perf/jvmti/libjvmti.c
@@ -12,6 +12,17 @@
static int has_line_numbers;
void *jvmti_agent;

+static void print_error(jvmtiEnv *jvmti, const char *msg, jvmtiError ret)
+{
+ char *err_msg = NULL;
+ jvmtiError err;
+ err = (*jvmti)->GetErrorName(jvmti, ret, &err_msg);
+ if (err == JVMTI_ERROR_NONE) {
+ warnx("%s failed with %s", msg, err_msg);
+ (*jvmti)->Deallocate(jvmti, (unsigned char *)err_msg);
+ }
+}
+
static jvmtiError
do_get_line_numbers(jvmtiEnv *jvmti, void *pc, jmethodID m, jint bci,
jvmti_line_info_t *tab, jint *nr)
@@ -22,8 +33,10 @@ do_get_line_numbers(jvmtiEnv *jvmti, void *pc, jmethodID m, jint bci,
jvmtiError ret;

ret = (*jvmti)->GetLineNumberTable(jvmti, m, &nr_lines, &loc_tab);
- if (ret != JVMTI_ERROR_NONE)
+ if (ret != JVMTI_ERROR_NONE) {
+ print_error(jvmti, "GetLineNumberTable", ret);
return ret;
+ }

for (i = 0; i < nr_lines; i++) {
if (loc_tab[i].start_location < bci) {
@@ -71,6 +84,8 @@ get_line_numbers(jvmtiEnv *jvmti, const void *compile_info, jvmti_line_info_t **
/* free what was allocated for nothing */
(*jvmti)->Deallocate(jvmti, (unsigned char *)lne);
nr_total += (int)nr;
+ } else {
+ print_error(jvmti, "GetLineNumberTable", ret);
}
}
}
@@ -130,7 +145,7 @@ compiled_method_load_cb(jvmtiEnv *jvmti,
ret = (*jvmti)->GetMethodDeclaringClass(jvmti, method,
&decl_class);
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: cannot get declaring class");
+ print_error(jvmti, "GetMethodDeclaringClass", ret);
return;
}

@@ -144,21 +159,21 @@ compiled_method_load_cb(jvmtiEnv *jvmti,

ret = (*jvmti)->GetSourceFileName(jvmti, decl_class, &file_name);
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: cannot get source filename ret=%d", ret);
+ print_error(jvmti, "GetSourceFileName", ret);
goto error;
}

ret = (*jvmti)->GetClassSignature(jvmti, decl_class,
&class_sign, NULL);
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: getclassignature failed");
+ print_error(jvmti, "GetClassSignature", ret);
goto error;
}

ret = (*jvmti)->GetMethodName(jvmti, method, &func_name,
&func_sign, NULL);
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: failed getmethodname");
+ print_error(jvmti, "GetMethodName", ret);
goto error;
}

@@ -253,7 +268,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __unused)

ret = (*jvmti)->AddCapabilities(jvmti, &caps1);
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: acquire compiled_method capability failed");
+ print_error(jvmti, "AddCapabilities", ret);
return -1;
}
ret = (*jvmti)->GetJLocationFormat(jvmti, &format);
@@ -264,7 +279,9 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __unused)
ret = (*jvmti)->AddCapabilities(jvmti, &caps1);
if (ret == JVMTI_ERROR_NONE)
has_line_numbers = 1;
- }
+ } else if (ret != JVMTI_ERROR_NONE)
+ print_error(jvmti, "GetJLocationFormat", ret);
+

memset(&cb, 0, sizeof(cb));

@@ -273,21 +290,21 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __unused)

ret = (*jvmti)->SetEventCallbacks(jvmti, &cb, sizeof(cb));
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: cannot set event callbacks");
+ print_error(jvmti, "SetEventCallbacks", ret);
return -1;
}

ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,
JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: setnotification failed for method_load");
+ print_error(jvmti, "SetEventNotificationMode(METHOD_LOAD)", ret);
return -1;
}

ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,
JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL);
if (ret != JVMTI_ERROR_NONE) {
- warnx("jvmti: setnotification failed on code_generated");
+ print_error(jvmti, "SetEventNotificationMode(CODE_GENERATED)", ret);
return -1;
}
return 0;
--
1.9.1