The sampling profile should have an option to sample from C frames.
https://bugs.webkit.org/show_bug.cgi?id=167614
Reviewed by Saam Barati.
We should be able to use the sampling profiler, at least
internally, to trace C calls. This patch only modifies the JSC
shell although it would be nice to add it to the Web Inspector in
a future patch.
* runtime/Options.h:
* runtime/SamplingProfiler.cpp:
(JSC::FrameWalker::FrameWalker):
(JSC::FrameWalker::walk):
(JSC::FrameWalker::recordJSFrame):
(JSC::CFrameWalker::CFrameWalker):
(JSC::CFrameWalker::walk):
(JSC::CFrameWalker::isCFrame):
(JSC::CFrameWalker::advanceToParentFrame):
(JSC::CFrameWalker::frame):
(JSC::SamplingProfiler::takeSample):
(JSC::SamplingProfiler::processUnverifiedStackTraces):
(JSC::SamplingProfiler::StackFrame::displayName):
* runtime/SamplingProfiler.h:
(JSC::SamplingProfiler::UnprocessedStackFrame::UnprocessedStackFrame):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@211542 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/runtime/SamplingProfiler.cpp b/Source/JavaScriptCore/runtime/SamplingProfiler.cpp
index 2e07a04..411b76d 100644
--- a/Source/JavaScriptCore/runtime/SamplingProfiler.cpp
+++ b/Source/JavaScriptCore/runtime/SamplingProfiler.cpp
@@ -51,6 +51,11 @@
#include <wtf/RefPtr.h>
#include <wtf/text/StringBuilder.h>
+#if OS(DARWIN)
+#include <cxxabi.h>
+#include <dlfcn.h>
+#endif
+
namespace JSC {
static double sNumTotalStackTraces = 0;
@@ -76,7 +81,7 @@
class FrameWalker {
public:
- FrameWalker(ExecState* callFrame, VM& vm, const LockHolder& codeBlockSetLocker, const LockHolder& machineThreadsLocker)
+ FrameWalker(VM& vm, ExecState* callFrame, const LockHolder& codeBlockSetLocker, const LockHolder& machineThreadsLocker)
: m_vm(vm)
, m_callFrame(callFrame)
, m_vmEntryFrame(vm.topVMEntryFrame)
@@ -93,15 +98,7 @@
resetAtMachineFrame();
size_t maxStackTraceSize = stackTrace.size();
while (!isAtTop() && !m_bailingOut && m_depth < maxStackTraceSize) {
- CallSiteIndex callSiteIndex;
- JSValue unsafeCallee = m_callFrame->unsafeCallee();
- CodeBlock* codeBlock = m_callFrame->unsafeCodeBlock();
- if (codeBlock) {
- ASSERT(isValidCodeBlock(codeBlock));
- callSiteIndex = m_callFrame->unsafeCallSiteIndex();
- }
- stackTrace[m_depth] = UnprocessedStackFrame(codeBlock, JSValue::encode(unsafeCallee), callSiteIndex);
- m_depth++;
+ recordJSFrame(stackTrace);
advanceToParentFrame();
resetAtMachineFrame();
}
@@ -115,7 +112,21 @@
return !m_bailingOut;
}
-private:
+protected:
+
+ SUPPRESS_ASAN
+ void recordJSFrame(Vector<UnprocessedStackFrame>& stackTrace)
+ {
+ CallSiteIndex callSiteIndex;
+ JSValue unsafeCallee = m_callFrame->unsafeCallee();
+ CodeBlock* codeBlock = m_callFrame->unsafeCodeBlock();
+ if (codeBlock) {
+ ASSERT(isValidCodeBlock(codeBlock));
+ callSiteIndex = m_callFrame->unsafeCallSiteIndex();
+ }
+ stackTrace[m_depth] = UnprocessedStackFrame(codeBlock, JSValue::encode(unsafeCallee), callSiteIndex);
+ m_depth++;
+ }
SUPPRESS_ASAN
void advanceToParentFrame()
@@ -154,7 +165,7 @@
}
}
- bool isValidFramePointer(ExecState* exec)
+ bool isValidFramePointer(void* exec)
{
uint8_t* fpCast = bitwise_cast<uint8_t*>(exec);
for (MachineThreads::Thread* thread = m_vm.heap.machineThreads().threadsListHead(m_machineThreadsLocker); thread; thread = thread->next) {
@@ -185,6 +196,85 @@
size_t m_depth { 0 };
};
+class CFrameWalker : public FrameWalker {
+public:
+ typedef FrameWalker Base;
+
+ CFrameWalker(VM& vm, void* machineFrame, ExecState* callFrame, const LockHolder& codeBlockSetLocker, const LockHolder& machineThreadsLocker)
+ : Base(vm, callFrame, codeBlockSetLocker, machineThreadsLocker)
+ , m_machineFrame(machineFrame)
+ {
+ }
+
+ size_t walk(Vector<UnprocessedStackFrame>& stackTrace, bool& didRunOutOfSpace)
+ {
+ if (sReportStats)
+ sNumTotalWalks++;
+ resetAtMachineFrame();
+ size_t maxStackTraceSize = stackTrace.size();
+ // The way the C walker decides if a frame it is about to trace is C or JS is by
+ // ensuring m_callFrame points to some frame above the machineFrame.
+ if (!isAtTop() && !m_bailingOut && m_machineFrame == m_callFrame) {
+ recordJSFrame(stackTrace);
+ Base::advanceToParentFrame();
+ resetAtMachineFrame();
+ }
+
+ while (!isAtTop() && !m_bailingOut && m_depth < maxStackTraceSize) {
+ if (m_machineFrame >= m_callFrame) {
+ // If we get to this state we probably have an invalid trace.
+ m_bailingOut = true;
+ break;
+ }
+
+ if (isCFrame()) {
+ RELEASE_ASSERT(!LLInt::isLLIntPC(frame()->callerFrame));
+ stackTrace[m_depth] = UnprocessedStackFrame(frame()->pc);
+ m_depth++;
+ } else
+ recordJSFrame(stackTrace);
+ advanceToParentFrame();
+ resetAtMachineFrame();
+ }
+ didRunOutOfSpace = m_depth >= maxStackTraceSize && !isAtTop();
+ reportStats();
+ return m_depth;
+ }
+
+private:
+
+ bool isCFrame()
+ {
+ return frame()->callerFrame != m_callFrame;
+ }
+
+ void advanceToParentFrame()
+ {
+ if (!isCFrame())
+ Base::advanceToParentFrame();
+ m_machineFrame = frame()->callerFrame;
+ }
+
+ void resetAtMachineFrame()
+ {
+ if (!isValidFramePointer(m_machineFrame)) {
+ // Guard against pausing the process at weird program points.
+ m_bailingOut = true;
+ if (sReportStats)
+ sNumFailedWalks++;
+ return;
+ }
+ Base::resetAtMachineFrame();
+ }
+
+ CallerFrameAndPC* frame()
+ {
+ return reinterpret_cast<CallerFrameAndPC*>(m_machineFrame);
+ }
+
+ void* m_machineFrame;
+};
+
SamplingProfiler::SamplingProfiler(VM& vm, RefPtr<Stopwatch>&& stopwatch)
: m_vm(vm)
, m_stopwatch(WTFMove(stopwatch))
@@ -258,6 +348,7 @@
if (didSuspend) {
// While the JSC thread is suspended, we can't do things like malloc because the JSC thread
// may be holding the malloc lock.
+ void* machineFrame;
ExecState* callFrame;
void* machinePC;
bool topFrameIsLLInt = false;
@@ -265,7 +356,8 @@
{
MachineThreads::Thread::Registers registers;
m_jscExecutionThread->getRegisters(registers);
- callFrame = static_cast<ExecState*>(registers.framePointer());
+ machineFrame = registers.framePointer();
+ callFrame = static_cast<ExecState*>(machineFrame);
machinePC = registers.instructionPointer();
llintPC = registers.llintPC();
m_jscExecutionThread->freeRegisters(registers);
@@ -291,8 +383,12 @@
size_t walkSize;
bool wasValidWalk;
bool didRunOutOfVectorSpace;
- {
- FrameWalker walker(callFrame, m_vm, codeBlockSetLocker, machineThreadsLocker);
+ if (Options::sampleCCode()) {
+ CFrameWalker walker(m_vm, machineFrame, callFrame, codeBlockSetLocker, machineThreadsLocker);
+ walkSize = walker.walk(m_currentFrames, didRunOutOfVectorSpace);
+ wasValidWalk = walker.wasValidWalk();
+ } else {
+ FrameWalker walker(m_vm, callFrame, codeBlockSetLocker, machineThreadsLocker);
walkSize = walker.walk(m_currentFrames, didRunOutOfVectorSpace);
wasValidWalk = walker.wasValidWalk();
}
@@ -527,12 +623,17 @@
#else
appendCodeBlockNoInlining();
#endif
+ } else if (unprocessedStackFrame.cCodePC) {
+ appendEmptyFrame();
+ stackTrace.frames.last().cCodePC = unprocessedStackFrame.cCodePC;
+ stackTrace.frames.last().frameType = FrameType::C;
} else
appendEmptyFrame();
// Note that this is okay to do if we walked the inline stack because
// the machine frame will be at the top of the processed stack trace.
- storeCalleeIntoLastFrame(unprocessedStackFrame.unverifiedCallee);
+ if (!unprocessedStackFrame.cCodePC)
+ storeCalleeIntoLastFrame(unprocessedStackFrame.unverifiedCallee);
}
}
@@ -644,8 +745,23 @@
return name;
}
- if (frameType == FrameType::Unknown)
- return ASCIILiteral("(unknown)");
+ if (frameType == FrameType::Unknown || frameType == FrameType::C) {
+#if OS(DARWIN)
+ if (frameType == FrameType::C) {
+ const char* mangledName = nullptr;
+ const char* cxaDemangled = nullptr;
+ Dl_info info;
+ if (dladdr(cCodePC, &info) && info.dli_sname)
+ mangledName = info.dli_sname;
+ if (mangledName) {
+ cxaDemangled = abi::__cxa_demangle(mangledName, 0, 0, 0);
+ return String(cxaDemangled ? cxaDemangled : mangledName);
+ }
+ WTF::dataLog("couldn't get a name");
+ }
+#endif
+ return ASCIILiteral("(unknown12)");
+ }
if (frameType == FrameType::Host)
return ASCIILiteral("(host)");
@@ -671,7 +787,7 @@
return name;
}
- if (frameType == FrameType::Unknown)
+ if (frameType == FrameType::Unknown || frameType == FrameType::C)
return ASCIILiteral("(unknown)");
if (frameType == FrameType::Host)
return ASCIILiteral("(host)");
@@ -698,7 +814,7 @@
int SamplingProfiler::StackFrame::functionStartLine()
{
- if (frameType == FrameType::Unknown || frameType == FrameType::Host)
+ if (frameType == FrameType::Unknown || frameType == FrameType::Host || frameType == FrameType::C)
return -1;
if (executable->isHostFunction())
@@ -708,7 +824,7 @@
unsigned SamplingProfiler::StackFrame::functionStartColumn()
{
- if (frameType == FrameType::Unknown || frameType == FrameType::Host)
+ if (frameType == FrameType::Unknown || frameType == FrameType::Host || frameType == FrameType::C)
return std::numeric_limits<unsigned>::max();
if (executable->isHostFunction())
@@ -719,7 +835,7 @@
intptr_t SamplingProfiler::StackFrame::sourceID()
{
- if (frameType == FrameType::Unknown || frameType == FrameType::Host)
+ if (frameType == FrameType::Unknown || frameType == FrameType::Host || frameType == FrameType::C)
return -1;
if (executable->isHostFunction())
@@ -730,7 +846,7 @@
String SamplingProfiler::StackFrame::url()
{
- if (frameType == FrameType::Unknown || frameType == FrameType::Host)
+ if (frameType == FrameType::Unknown || frameType == FrameType::Host || frameType == FrameType::C)
return emptyString();
if (executable->isHostFunction())
@@ -968,6 +1084,7 @@
case SamplingProfiler::FrameType::Host:
out.print("Host");
break;
+ case SamplingProfiler::FrameType::C:
case SamplingProfiler::FrameType::Unknown:
out.print("Unknown");
break;
