[tip:perf/core] perf jit: Improve error messages from JVMTI

From: tip-bot for Stephane Eranian
Date: Mon Oct 24 2016 - 15:00:18 EST


Commit-ID: cdd75e3b0d1e668bc498f18f0ea8353f9f955114
Gitweb: http://git.kernel.org/tip/cdd75e3b0d1e668bc498f18f0ea8353f9f955114
Author: Stephane Eranian <eranian@xxxxxxxxxx>
AuthorDate: Thu, 13 Oct 2016 03:59:35 -0700
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 24 Oct 2016 11:07:37 -0300

perf jit: Improve error messages from JVMTI

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>
Cc: Anton Blanchard <anton@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Nilay Vaish <nilayvaish@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1476356383-30100-2-git-send-email-eranian@xxxxxxxxxx
[ Handle failure to convert numeric error to a string in print_error() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/jvmti/libjvmti.c | 39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/tools/perf/jvmti/libjvmti.c b/tools/perf/jvmti/libjvmti.c
index ac12e4b..5612641 100644
--- a/tools/perf/jvmti/libjvmti.c
+++ b/tools/perf/jvmti/libjvmti.c
@@ -12,6 +12,19 @@
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);
+ } else {
+ warnx("%s failed with an unknown error %d", msg, ret);
+ }
+}
+
static jvmtiError
do_get_line_numbers(jvmtiEnv *jvmti, void *pc, jmethodID m, jint bci,
jvmti_line_info_t *tab, jint *nr)
@@ -22,8 +35,10 @@ 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 +86,8 @@ 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 +147,7 @@ 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 +161,21 @@ 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 +270,7 @@ 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 +281,9 @@ 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 +292,21 @@ 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;