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#include "node_dtrace.h"
#include "node_win32_etw_provider.h"
#include "node_etw_provider.h"
#include "node_win32_etw_provider-inl.h"
namespace node {
using v8::JitCodeEvent;
using v8::V8;
HMODULE advapi;
REGHANDLE node_provider;
EventRegisterFunc event_register;
EventUnregisterFunc event_unregister;
EventWriteFunc event_write;
int events_enabled;
static uv_async_t dispatch_etw_events_change_async;
struct v8tags {
char prefix[32 - sizeof(size_t)];
size_t prelen;
};
// The v8 CODE_ADDED event name has a prefix indicating the type of event.
// Many of these are internal to v8.
// The trace_codes array specifies which types are written.
struct v8tags trace_codes[] = {
#define MAKE_V8TAG(s) { s, sizeof(s) - 1 }
MAKE_V8TAG("LazyCompile:"),
MAKE_V8TAG("Script:"),
MAKE_V8TAG("Function:"),
MAKE_V8TAG("RegExp:"),
MAKE_V8TAG("Eval:")
#undef MAKE_V8TAG
};
/* Below are some code prefixes which are not being written.
* "Builtin:"
* "Stub:"
* "CallIC:"
* "LoadIC:"
* "KeyedLoadIC:"
* "StoreIC:"
* "KeyedStoreIC:"
* "CallPreMonomorphic:"
* "CallInitialize:"
* "CallMiss:"
* "CallMegamorphic:"
*/
// v8 sometimes puts a '*' or '~' in front of the name.
#define V8_MARKER1 '*'
#define V8_MARKER2 '~'
// If prefix is not in filtered list return -1,
// else return length of prefix and marker.
int FilterCodeEvents(const char* name, size_t len) {
for (size_t i = 0; i < arraysize(trace_codes); i++) {
size_t prelen = trace_codes[i].prelen;
if (prelen < len) {
if (strncmp(name, trace_codes[i].prefix, prelen) == 0) {
if (name[prelen] == V8_MARKER1 || name[prelen] == V8_MARKER2)
prelen++;
return prelen;
}
}
}
return -1;
}
// callback from V8 module passes symbol and address info for stack walk
void CodeAddressNotification(const JitCodeEvent* jevent) {
int pre_offset = 0;
if (NODE_V8SYMBOL_ENABLED()) {
switch (jevent->type) {
case JitCodeEvent::CODE_ADDED:
pre_offset = FilterCodeEvents(jevent->name.str, jevent->name.len);
if (pre_offset >= 0) {
// skip over prefix and marker
NODE_V8SYMBOL_ADD(jevent->name.str + pre_offset,
jevent->name.len - pre_offset,
jevent->code_start,
jevent->code_len);
}
break;
case JitCodeEvent::CODE_REMOVED:
NODE_V8SYMBOL_REMOVE(jevent->code_start, 0);
break;
case JitCodeEvent::CODE_MOVED:
NODE_V8SYMBOL_MOVE(jevent->code_start, jevent->new_code_start);
break;
default:
break;
}
}
}
// Call v8 to enable or disable code event callbacks.
// Must be on default thread to do this.
// Note: It is possible to call v8 from ETW thread, but then
// event callbacks are received in the same thread. Attempts
// to write ETW events in this thread will fail.
void etw_events_change_async(uv_async_t* handle) {
if (events_enabled > 0) {
NODE_V8SYMBOL_RESET();
v8::Isolate::GetCurrent()->SetJitCodeEventHandler(
v8::kJitCodeEventEnumExisting,
CodeAddressNotification);
} else {
v8::Isolate::GetCurrent()->SetJitCodeEventHandler(
v8::kJitCodeEventDefault,
nullptr);
}
}
// This callback is called by ETW when consumers of our provider
// are enabled or disabled.
// The callback is dispatched on ETW thread.
// Before calling into V8 to enable code events, switch to default thread.
void NTAPI etw_events_enable_callback(
LPCGUID SourceId,
ULONG IsEnabled,
UCHAR Level,
ULONGLONG MatchAnyKeyword,
ULONGLONG MatchAllKeywords,
PEVENT_FILTER_DESCRIPTOR FilterData,
PVOID CallbackContext) {
if (IsEnabled) {
events_enabled++;
if (events_enabled == 1) {
uv_async_send(&dispatch_etw_events_change_async);
}
} else {
events_enabled--;
if (events_enabled == 0) {
uv_async_send(&dispatch_etw_events_change_async);
}
}
}
void init_etw() {
events_enabled = 0;
advapi = LoadLibraryW(L"advapi32.dll");
if (advapi) {
event_register = (EventRegisterFunc)
GetProcAddress(advapi, "EventRegister");
event_unregister = (EventUnregisterFunc)
GetProcAddress(advapi, "EventUnregister");
event_write = (EventWriteFunc)GetProcAddress(advapi, "EventWrite");
// create async object used to invoke main thread from callback
CHECK_EQ(0, uv_async_init(uv_default_loop(),
&dispatch_etw_events_change_async,
etw_events_change_async));
uv_unref(reinterpret_cast<uv_handle_t*>(&dispatch_etw_events_change_async));
if (event_register) {
DWORD status = event_register(&NODE_ETW_PROVIDER,
etw_events_enable_callback,
nullptr,
&node_provider);
CHECK_EQ(status, ERROR_SUCCESS);
}
}
}
void shutdown_etw() {
if (advapi && event_unregister && node_provider) {
event_unregister(node_provider);
node_provider = 0;
}
events_enabled = 0;
v8::Isolate::GetCurrent()->SetJitCodeEventHandler(
v8::kJitCodeEventDefault,
nullptr);
if (advapi) {
FreeLibrary(advapi);
advapi = nullptr;
}
}
} // namespace node
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