Pull request

Show trace-events filename/lineno in fmt string errors and send -d trace:help
 output to stdout for consistency.
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Merge remote-tracking branch 'remotes/stefanha-gitlab/tags/tracing-pull-request' into staging

Pull request

Show trace-events filename/lineno in fmt string errors and send -d trace:help
output to stdout for consistency.

# gpg: Signature made Mon 04 Jan 2021 14:26:58 GMT
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha-gitlab/tags/tracing-pull-request:
  tracetool: show trace-events filename/lineno in fmt string errors
  tracetool: add input filename and line number to Event
  tracetool: add out_lineno and out_next_lineno to out()
  tracetool: add output filename command-line argument
  trace: Send "-d trace:help" output to stdout

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

docs/devel/tracing.txt

@@ -318,7 +318,8 @@ probes:
                          --target-type system \
                          --target-name x86_64 \
                          --group=all \
-                         trace-events-all >qemu.stp
+                         trace-events-all \
+                         qemu.stp
 
 To facilitate simple usage of systemtap where there merely needs to be printf
 logging of certain probes, a helper script "qemu-trace-stap" is provided.

meson.build

@@ -1901,7 +1901,6 @@ foreach target : target_dirs
         custom_target(exe['name'] + stp['ext'],
                       input: trace_events_all,
                       output: exe['name'] + stp['ext'],
-                      capture: true,
                       install: stp['install'],
                       install_dir: get_option('datadir') / 'systemtap/tapset',
                       command: [
@@ -1910,7 +1909,7 @@ foreach target : target_dirs
                         '--target-name=' + target_name,
                         '--target-type=' + target_type,
                         '--probe-prefix=qemu.' + target_type + '.' + target_name,
-                        '@INPUT@',
+                        '@INPUT@', '@OUTPUT@'
                       ])
       endforeach
     endif

scripts/tracetool.py

@@ -16,7 +16,7 @@ __email__      = "stefanha@redhat.com"
 import sys
 import getopt
 
-from tracetool import error_write, out
+from tracetool import error_write, out, out_open
 import tracetool.backend
 import tracetool.format
 
@@ -32,7 +32,7 @@ def error_opt(msg = None):
     format_descr = "\n".join([ "    %-15s %s" % (n, d)
                                for n,d in tracetool.format.get_list() ])
     error_write("""\
-Usage: %(script)s --format=<format> --backends=<backends> [<options>]
+Usage: %(script)s --format=<format> --backends=<backends> [<options>] <trace-events> ... <output>
 
 Backends:
 %(backends)s
@@ -135,13 +135,15 @@ def main(args):
         if probe_prefix is None:
             probe_prefix = ".".join(["qemu", target_type, target_name])
 
-    if len(args) < 1:
+    if len(args) < 2:
-        error_opt("missing trace-events filepath")
+        error_opt("missing trace-events and output filepaths")
     events = []
-    for arg in args:
+    for arg in args[:-1]:
         with open(arg, "r") as fh:
             events.extend(tracetool.read_events(fh, arg))
 
+    out_open(args[-1])
+
     try:
         tracetool.generate(events, arg_group, arg_format, arg_backends,
                            binary=binary, probe_prefix=probe_prefix)

scripts/tracetool/__init__.py

@@ -31,14 +31,36 @@ def error(*lines):
     sys.exit(1)
 
 
+out_lineno = 1
+out_filename = '<none>'
+out_fobj = sys.stdout
+
+def out_open(filename):
+    global out_filename, out_fobj
+    out_filename = filename
+    out_fobj = open(filename, 'wt')
+
 def out(*lines, **kwargs):
     """Write a set of output lines.
 
     You can use kwargs as a shorthand for mapping variables when formatting all
     the strings in lines.
+
+    The 'out_lineno' kwarg is automatically added to reflect the current output
+    file line number. The 'out_next_lineno' kwarg is also automatically added
+    with the next output line number. The 'out_filename' kwarg is automatically
+    added with the output filename.
     """
-    lines = [ l % kwargs for l in lines ]
+    global out_lineno
-    sys.stdout.writelines("\n".join(lines) + "\n")
+    output = []
+    for l in lines:
+        kwargs['out_lineno'] = out_lineno
+        kwargs['out_next_lineno'] = out_lineno + 1
+        kwargs['out_filename'] = out_filename
+        output.append(l % kwargs)
+        out_lineno += 1
+
+    out_fobj.writelines("\n".join(output) + "\n")
 
 # We only want to allow standard C types or fixed sized
 # integer types. We don't want QEMU specific types
@@ -196,6 +218,10 @@ class Event(object):
         Properties of the event.
     args : Arguments
         The event arguments.
+    lineno : int
+        The line number in the input file.
+    filename : str
+        The path to the input file.
 
     """
 
@@ -208,7 +234,7 @@ class Event(object):
 
     _VALID_PROPS = set(["disable", "tcg", "tcg-trans", "tcg-exec", "vcpu"])
 
-    def __init__(self, name, props, fmt, args, orig=None,
+    def __init__(self, name, props, fmt, args, lineno, filename, orig=None,
                  event_trans=None, event_exec=None):
         """
         Parameters
@@ -221,6 +247,10 @@ class Event(object):
             Event printing format string(s).
         args : Arguments
             Event arguments.
+        lineno : int
+            The line number in the input file.
+        filename : str
+            The path to the input file.
         orig : Event or None
             Original Event before transformation/generation.
         event_trans : Event or None
@@ -233,6 +263,8 @@ class Event(object):
         self.properties = props
         self.fmt = fmt
         self.args = args
+        self.lineno = int(lineno)
+        self.filename = str(filename)
         self.event_trans = event_trans
         self.event_exec = event_exec
 
@@ -254,16 +286,21 @@ class Event(object):
     def copy(self):
         """Create a new copy."""
         return Event(self.name, list(self.properties), self.fmt,
-                     self.args.copy(), self, self.event_trans, self.event_exec)
+                     self.args.copy(), self.lineno, self.filename,
+                     self, self.event_trans, self.event_exec)
 
     @staticmethod
-    def build(line_str):
+    def build(line_str, lineno, filename):
         """Build an Event instance from a string.
 
         Parameters
         ----------
         line_str : str
             Line describing the event.
+        lineno : int
+            Line number in input file.
+        filename : str
+            Path to input file.
         """
         m = Event._CRE.match(line_str)
         assert m is not None
@@ -293,7 +330,7 @@ class Event(object):
         if "tcg" in props and isinstance(fmt, str):
             raise ValueError("Events with 'tcg' property must have two format strings")
 
-        event = Event(name, props, fmt, args)
+        event = Event(name, props, fmt, args, lineno, filename)
 
         # add implicit arguments when using the 'vcpu' property
         import tracetool.vcpu
@@ -338,6 +375,8 @@ class Event(object):
                      list(self.properties),
                      self.fmt,
                      self.args.transform(*trans),
+                     self.lineno,
+                     self.filename,
                      self)
 
 
@@ -364,7 +403,7 @@ def read_events(fobj, fname):
             continue
 
         try:
-            event = Event.build(line)
+            event = Event.build(line, lineno, fname)
         except ValueError as e:
             arg0 = 'Error at %s:%d: %s' % (fname, lineno, e.args[0])
             e.args = (arg0,) + e.args[1:]

scripts/tracetool/backend/ftrace.py

@@ -33,8 +33,10 @@ def generate_h(event, group):
         '        int unused __attribute__ ((unused));',
         '        int trlen;',
         '        if (trace_event_get_state(%(event_id)s)) {',
+        '#line %(event_lineno)d "%(event_filename)s"',
         '            trlen = snprintf(ftrace_buf, MAX_TRACE_STRLEN,',
         '                             "%(name)s " %(fmt)s "\\n" %(argnames)s);',
+        '#line %(out_next_lineno)d "%(out_filename)s"',
         '            trlen = MIN(trlen, MAX_TRACE_STRLEN - 1);',
         '            unused = write(trace_marker_fd, ftrace_buf, trlen);',
         '        }',
@@ -42,6 +44,8 @@ def generate_h(event, group):
         name=event.name,
         args=event.args,
         event_id="TRACE_" + event.name.upper(),
+        event_lineno=event.lineno,
+        event_filename=event.filename,
         fmt=event.fmt.rstrip("\n"),
         argnames=argnames)
 

scripts/tracetool/backend/log.py

@@ -37,12 +37,16 @@ def generate_h(event, group):
     out('    if (%(cond)s && qemu_loglevel_mask(LOG_TRACE)) {',
         '        struct timeval _now;',
         '        gettimeofday(&_now, NULL);',
+        '#line %(event_lineno)d "%(event_filename)s"',
         '        qemu_log("%%d@%%zu.%%06zu:%(name)s " %(fmt)s "\\n",',
         '                 qemu_get_thread_id(),',
         '                 (size_t)_now.tv_sec, (size_t)_now.tv_usec',
         '                 %(argnames)s);',
+        '#line %(out_next_lineno)d "%(out_filename)s"',
         '    }',
         cond=cond,
+        event_lineno=event.lineno,
+        event_filename=event.filename,
         name=event.name,
         fmt=event.fmt.rstrip("\n"),
         argnames=argnames)

scripts/tracetool/backend/syslog.py

@@ -35,9 +35,13 @@ def generate_h(event, group):
         cond = "trace_event_get_state(%s)" % ("TRACE_" + event.name.upper())
 
     out('    if (%(cond)s) {',
+        '#line %(event_lineno)d "%(event_filename)s"',
         '        syslog(LOG_INFO, "%(name)s " %(fmt)s %(argnames)s);',
+        '#line %(out_next_lineno)d "%(out_filename)s"',
         '    }',
         cond=cond,
+        event_lineno=event.lineno,
+        event_filename=event.filename,
         name=event.name,
         fmt=event.fmt.rstrip("\n"),
         argnames=argnames)

trace/control.c

@@ -125,16 +125,16 @@ TraceEvent *trace_event_iter_next(TraceEventIter *iter)
     return NULL;
 }
 
-void trace_list_events(void)
+void trace_list_events(FILE *f)
 {
     TraceEventIter iter;
     TraceEvent *ev;
     trace_event_iter_init(&iter, NULL);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
-        fprintf(stderr, "%s\n", trace_event_get_name(ev));
+        fprintf(f, "%s\n", trace_event_get_name(ev));
     }
 #ifdef CONFIG_TRACE_DTRACE
-    fprintf(stderr, "This list of names of trace points may be incomplete "
+    fprintf(f, "This list of names of trace points may be incomplete "
                "when using the DTrace/SystemTap backends.\n"
                "Run 'qemu-trace-stap list %s' to print the full list.\n",
             error_get_progname());
@@ -176,7 +176,7 @@ static void do_trace_enable_events(const char *line_buf)
 void trace_enable_events(const char *line_buf)
 {
     if (is_help_option(line_buf)) {
-        trace_list_events();
+        trace_list_events(stdout);
         if (monitor_cur() == NULL) {
             exit(0);
         }

trace/control.h

@@ -201,10 +201,11 @@ void trace_fini_vcpu(CPUState *vcpu);
 
 /**
  * trace_list_events:
+ * @f: Where to send output.
  *
  * List all available events.
  */
-void trace_list_events(void);
+void trace_list_events(FILE *f);
 
 /**
  * trace_enable_events:

trace/meson.build

@@ -11,20 +11,17 @@ foreach dir : [ '.' ] + trace_events_subdirs
   trace_h = custom_target(fmt.format('trace', 'h'),
                           output: fmt.format('trace', 'h'),
                           input: trace_events_file,
-                          command: [ tracetool, group, '--format=h', '@INPUT@' ],
+                          command: [ tracetool, group, '--format=h', '@INPUT@', '@OUTPUT@' ])
-                          capture: true)
   genh += trace_h
   trace_c = custom_target(fmt.format('trace', 'c'),
                           output: fmt.format('trace', 'c'),
                           input: trace_events_file,
-                          command: [ tracetool, group, '--format=c', '@INPUT@' ],
+                          command: [ tracetool, group, '--format=c', '@INPUT@', '@OUTPUT@' ])
-                          capture: true)
   if 'CONFIG_TRACE_UST' in config_host
     trace_ust_h = custom_target(fmt.format('trace-ust', 'h'),
                                 output: fmt.format('trace-ust', 'h'),
                                 input: trace_events_file,
-                                command: [ tracetool, group, '--format=ust-events-h', '@INPUT@' ],
+                                command: [ tracetool, group, '--format=ust-events-h', '@INPUT@', '@OUTPUT@' ])
-                                capture: true)
     trace_ss.add(trace_ust_h, lttng, urcubp)
     genh += trace_ust_h
   endif
@@ -33,8 +30,7 @@ foreach dir : [ '.' ] + trace_events_subdirs
     trace_dtrace = custom_target(fmt.format('trace-dtrace', 'dtrace'),
                                  output: fmt.format('trace-dtrace', 'dtrace'),
                                  input: trace_events_file,
-                                 command: [ tracetool, group, '--format=d', '@INPUT@' ],
+                                 command: [ tracetool, group, '--format=d', '@INPUT@', '@OUTPUT@' ])
-                                 capture: true)
     trace_dtrace_h = custom_target(fmt.format('trace-dtrace', 'h'),
                                    output: fmt.format('trace-dtrace', 'h'),
                                    input: trace_dtrace,
@@ -69,8 +65,7 @@ foreach d : [
   gen = custom_target(d[0],
                 output: d[0],
                 input: meson.source_root() / 'trace-events',
-                command: [ tracetool, '--group=root', '--format=@0@'.format(d[1]), '@INPUT@' ],
+                command: [ tracetool, '--group=root', '--format=@0@'.format(d[1]), '@INPUT@', '@OUTPUT@' ])
-                capture: true)
   specific_ss.add(gen)
 endforeach
 
@@ -78,13 +73,11 @@ if 'CONFIG_TRACE_UST' in config_host
   trace_ust_all_h = custom_target('trace-ust-all.h',
                                   output: 'trace-ust-all.h',
                                   input: trace_events_files,
-                                  command: [ tracetool, '--group=all', '--format=ust-events-h', '@INPUT@' ],
+                                  command: [ tracetool, '--group=all', '--format=ust-events-h', '@INPUT@', '@OUTPUT@' ])
-                                  capture: true)
   trace_ust_all_c = custom_target('trace-ust-all.c',
                                   output: 'trace-ust-all.c',
                                   input: trace_events_files,
-                                  command: [ tracetool, '--group=all', '--format=ust-events-c', '@INPUT@' ],
+                                  command: [ tracetool, '--group=all', '--format=ust-events-c', '@INPUT@', '@OUTPUT@' ])
-                                  capture: true)
   trace_ss.add(trace_ust_all_h, trace_ust_all_c)
   genh += trace_ust_all_h
 endif