Import QEMU upstream snapshot d2e570c

Upstream: https://gitlab.com/qemu-project/qemu.git

Upstream-Commit: d2e570cc0f97b936902a5b1b86b73c0f5998b475

scripts/tracetool/backend/dtrace.py

@@ -0,0 +1,103 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+"""
+DTrace/SystemTAP backend.
+"""
+
+__author__     = "Lluís Vilanova <[email protected]>"
+__copyright__  = "Copyright 2012-2017, Lluís Vilanova <[email protected]>"
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "[email protected]"
+
+
+from tracetool import out
+
+
+PUBLIC = True
+
+
+PROBEPREFIX = None
+
+def probeprefix():
+    if PROBEPREFIX is None:
+        raise ValueError("you must set PROBEPREFIX")
+    return PROBEPREFIX
+
+
+BINARY = None
+
+def binary():
+    if BINARY is None:
+        raise ValueError("you must set BINARY")
+    return BINARY
+
+
+def generate_h_begin(events, group):
+    if group == "root":
+        header = "trace-dtrace-root.h"
+    else:
+        header = "trace-dtrace-%s.h" % group
+
+    # Workaround for ust backend, which also includes <sys/sdt.h> and may
+    # require SDT_USE_VARIADIC to be defined. If dtrace includes <sys/sdt.h>
+    # first without defining SDT_USE_VARIADIC then ust breaks because the
+    # STAP_PROBEV() macro is not defined.
+    out('#ifndef SDT_USE_VARIADIC')
+    out('#define SDT_USE_VARIADIC 1')
+    out('#endif')
+
+    out('#include "%s"' % header,
+        '')
+
+    out('#undef SDT_USE_VARIADIC')
+
+    # SystemTap defines <provider>_<name>_ENABLED() but other DTrace
+    # implementations might not.
+    for e in events:
+        out('#ifndef QEMU_%(uppername)s_ENABLED',
+            '#define QEMU_%(uppername)s_ENABLED() true',
+            '#endif',
+            uppername=e.name.upper())
+
+def generate_h(event, group):
+    out('    QEMU_%(uppername)s(%(argnames)s);',
+        uppername=event.name.upper(),
+        argnames=", ".join(event.args.names()))
+
+
+def generate_h_backend_dstate(event, group):
+    out('    QEMU_%(uppername)s_ENABLED() || \\',
+        uppername=event.name.upper())
+
+
+def generate_rs_begin(events, group):
+    out('use std::cell::UnsafeCell;',
+        '',
+        'extern "C" {')
+    # These are the Rust declarations of the .probes section semaphores
+    # generated by dtrace(1) in its .o file output.
+    for e in events:
+        if 'disable' in e.properties:
+            continue
+        out('    #[allow(dead_code)]',
+            f'    static qemu_{e.name}_semaphore: UnsafeCell<u16>;')
+    out('}',
+        '')
+
+
+def generate_rs(event, group):
+    args = event.args.rust_call_extern()
+    if args:
+        args = ', ' + args
+
+    out(f'    ::trace::probe!(qemu, {event.name}{args});')
+
+
+def generate_rs_backend_dstate(event, group):
+    # Rust does not have access to the <provider>_<name>_ENABLED() macro from
+    # the dtrace(1) generated .h file. Use the matching semaphore declarations
+    # generated by generate_rs_begin() instead.
+    out('    (unsafe {qemu_%(n)s_semaphore.get().read_volatile()}) != 0 ||',
+        n=event.name)