[compiler-rt] [llvm] [ctxprof] root autodetection mechanism (PR #133147)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 31 12:33:13 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-pgo
Author: Mircea Trofin (mtrofin)
<details>
<summary>Changes</summary>
This is an optional mechanism that automatically detects roots. It's a best-effort mechanism, and its main goal is to *avoid* pointing at the message pump function as a root. This is the function that polls message queue(s) in an infinite loop, and is thus a bad root (it never exits).
High-level, when collection is requested - which should happen when a server has already been set up and handing requests - we spend a bit of time sampling all the server's threads. Each sample is a stack which we insert in a `PerThreadCallsiteTrie`. After a while, we run for each `PerThreadCallsiteTrie` the root detection logic. We then traverse all the `FunctionData`, find the ones matching the detected roots, and allocate a `ContextRoot` for them. From here, we special case `FunctionData` objects, in `__llvm_ctx_profile_get_context, that have a `CtxRoot` and route them to `__llvm_ctx_profile_start_context`.
For this to work, on the llvm side, we need to have all functions call `__llvm_ctx_profile_release_context` because they _might_ be roots. This comes at a slight (percentages) penalty during collection - which we can afford since the overall technique is ~5x faster than normal instrumentation. We can later explore conditionally enabling autoroot detection and avoiding this penalty, if desired.
Note that functions that `musttail call` can't have their return instrumented this way, and a subsequent patch will harden the mechanism against this case.
The mechanism could be used in combination with explicit root specification, too.
---
Patch is 33.28 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/133147.diff
11 Files Affected:
- (modified) compiler-rt/lib/ctx_profile/CMakeLists.txt (+1-1)
- (modified) compiler-rt/lib/ctx_profile/CtxInstrContextNode.h (+1)
- (modified) compiler-rt/lib/ctx_profile/CtxInstrProfiling.cpp (+53-23)
- (modified) compiler-rt/lib/ctx_profile/CtxInstrProfiling.h (+1-1)
- (modified) compiler-rt/lib/ctx_profile/RootAutoDetector.cpp (+94)
- (modified) compiler-rt/lib/ctx_profile/RootAutoDetector.h (+31)
- (added) compiler-rt/test/ctx_profile/TestCases/autodetect-roots.cpp (+188)
- (modified) compiler-rt/test/ctx_profile/TestCases/generate-context.cpp (+3-2)
- (modified) llvm/include/llvm/ProfileData/CtxInstrContextNode.h (+1)
- (modified) llvm/lib/Transforms/Instrumentation/PGOCtxProfLowering.cpp (+17-9)
- (modified) llvm/test/Transforms/PGOProfile/ctx-instrumentation.ll (+43-7)
``````````diff
diff --git a/compiler-rt/lib/ctx_profile/CMakeLists.txt b/compiler-rt/lib/ctx_profile/CMakeLists.txt
index bb606449c61b1..446ebc96408dd 100644
--- a/compiler-rt/lib/ctx_profile/CMakeLists.txt
+++ b/compiler-rt/lib/ctx_profile/CMakeLists.txt
@@ -27,7 +27,7 @@ endif()
add_compiler_rt_runtime(clang_rt.ctx_profile
STATIC
ARCHS ${CTX_PROFILE_SUPPORTED_ARCH}
- OBJECT_LIBS RTSanitizerCommon RTSanitizerCommonLibc
+ OBJECT_LIBS RTSanitizerCommon RTSanitizerCommonLibc RTSanitizerCommonSymbolizer
CFLAGS ${EXTRA_FLAGS}
SOURCES ${CTX_PROFILE_SOURCES}
ADDITIONAL_HEADERS ${CTX_PROFILE_HEADERS}
diff --git a/compiler-rt/lib/ctx_profile/CtxInstrContextNode.h b/compiler-rt/lib/ctx_profile/CtxInstrContextNode.h
index a42bf9ebb01ea..55423d95b3088 100644
--- a/compiler-rt/lib/ctx_profile/CtxInstrContextNode.h
+++ b/compiler-rt/lib/ctx_profile/CtxInstrContextNode.h
@@ -127,6 +127,7 @@ class ContextNode final {
/// MUTEXDECL takes one parameter, the name of a field that is a mutex.
#define CTXPROF_FUNCTION_DATA(PTRDECL, VOLATILE_PTRDECL, MUTEXDECL) \
PTRDECL(FunctionData, Next) \
+ VOLATILE_PTRDECL(void, EntryAddress) \
VOLATILE_PTRDECL(ContextRoot, CtxRoot) \
VOLATILE_PTRDECL(ContextNode, FlatCtx) \
MUTEXDECL(Mutex)
diff --git a/compiler-rt/lib/ctx_profile/CtxInstrProfiling.cpp b/compiler-rt/lib/ctx_profile/CtxInstrProfiling.cpp
index 10a6a8c1f71e5..d8b6947a62e60 100644
--- a/compiler-rt/lib/ctx_profile/CtxInstrProfiling.cpp
+++ b/compiler-rt/lib/ctx_profile/CtxInstrProfiling.cpp
@@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "CtxInstrProfiling.h"
+#include "RootAutoDetector.h"
#include "sanitizer_common/sanitizer_allocator_internal.h"
#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_atomic_clang.h"
@@ -43,6 +44,12 @@ Arena *FlatCtxArena = nullptr;
__thread bool IsUnderContext = false;
__sanitizer::atomic_uint8_t ProfilingStarted = {};
+__sanitizer::atomic_uintptr_t RootDetector = {};
+RootAutoDetector *getRootDetector() {
+ return reinterpret_cast<RootAutoDetector *>(
+ __sanitizer::atomic_load_relaxed(&RootDetector));
+}
+
// utility to taint a pointer by setting the LSB. There is an assumption
// throughout that the addresses of contexts are even (really, they should be
// align(8), but "even"-ness is the minimum assumption)
@@ -201,7 +208,7 @@ ContextNode *getCallsiteSlow(GUID Guid, ContextNode **InsertionPoint,
return Ret;
}
-ContextNode *getFlatProfile(FunctionData &Data, GUID Guid,
+ContextNode *getFlatProfile(FunctionData &Data, void *Callee, GUID Guid,
uint32_t NumCounters) {
if (ContextNode *Existing = Data.FlatCtx)
return Existing;
@@ -232,6 +239,7 @@ ContextNode *getFlatProfile(FunctionData &Data, GUID Guid,
auto *Ret = allocContextNode(AllocBuff, Guid, NumCounters, 0);
Data.FlatCtx = Ret;
+ Data.EntryAddress = Callee;
Data.Next = reinterpret_cast<FunctionData *>(
__sanitizer::atomic_load_relaxed(&AllFunctionsData));
while (!__sanitizer::atomic_compare_exchange_strong(
@@ -316,27 +324,32 @@ ContextNode *getUnhandledContext(FunctionData &Data, GUID Guid,
// entered once and never exit. They should be assumed to be entered before
// profiling starts - because profiling should start after the server is up
// and running (which is equivalent to "message pumps are set up").
- ContextRoot *R = __llvm_ctx_profile_current_context_root;
- if (!R) {
+ if (!CtxRoot) {
+ if (auto *RAD = getRootDetector())
+ RAD->sample();
+ else if (auto *CR = Data.CtxRoot)
+ return tryStartContextGivenRoot(CR, Guid, NumCounters, NumCallsites);
if (IsUnderContext || !__sanitizer::atomic_load_relaxed(&ProfilingStarted))
return TheScratchContext;
else
return markAsScratch(
- onContextEnter(*getFlatProfile(Data, Guid, NumCounters)));
+ onContextEnter(*getFlatProfile(Data, Callee, Guid, NumCounters)));
}
- auto [Iter, Ins] = R->Unhandled.insert({Guid, nullptr});
+ auto [Iter, Ins] = CtxRoot->Unhandled.insert({Guid, nullptr});
if (Ins)
- Iter->second =
- getCallsiteSlow(Guid, &R->FirstUnhandledCalleeNode, NumCounters, 0);
+ Iter->second = getCallsiteSlow(Guid, &CtxRoot->FirstUnhandledCalleeNode,
+ NumCounters, 0);
return markAsScratch(onContextEnter(*Iter->second));
}
ContextNode *__llvm_ctx_profile_get_context(FunctionData *Data, void *Callee,
GUID Guid, uint32_t NumCounters,
uint32_t NumCallsites) {
+ auto *CtxRoot = __llvm_ctx_profile_current_context_root;
// fast "out" if we're not even doing contextual collection.
- if (!__llvm_ctx_profile_current_context_root)
- return getUnhandledContext(*Data, Guid, NumCounters);
+ if (!CtxRoot)
+ return getUnhandledContext(*Data, Callee, Guid, NumCounters, NumCallsites,
+ nullptr);
// also fast "out" if the caller is scratch. We can see if it's scratch by
// looking at the interior pointer into the subcontexts vector that the caller
@@ -345,7 +358,8 @@ ContextNode *__llvm_ctx_profile_get_context(FunctionData *Data, void *Callee,
// precisely, aligned - 8 values)
auto **CallsiteContext = consume(__llvm_ctx_profile_callsite[0]);
if (!CallsiteContext || isScratch(CallsiteContext))
- return getUnhandledContext(*Data, Guid, NumCounters);
+ return getUnhandledContext(*Data, Callee, Guid, NumCounters, NumCallsites,
+ CtxRoot);
// if the callee isn't the expected one, return scratch.
// Signal handler(s) could have been invoked at any point in the execution.
@@ -363,7 +377,8 @@ ContextNode *__llvm_ctx_profile_get_context(FunctionData *Data, void *Callee,
// for that case.
auto *ExpectedCallee = consume(__llvm_ctx_profile_expected_callee[0]);
if (ExpectedCallee != Callee)
- return getUnhandledContext(*Data, Guid, NumCounters);
+ return getUnhandledContext(*Data, Callee, Guid, NumCounters, NumCallsites,
+ CtxRoot);
auto *Callsite = *CallsiteContext;
// in the case of indirect calls, we will have all seen targets forming a
@@ -385,24 +400,26 @@ ContextNode *__llvm_ctx_profile_get_context(FunctionData *Data, void *Callee,
return Ret;
}
-ContextNode *__llvm_ctx_profile_start_context(
- FunctionData *FData, GUID Guid, uint32_t Counters,
- uint32_t Callsites) SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
+ContextNode *__llvm_ctx_profile_start_context(FunctionData *FData, GUID Guid,
+ uint32_t Counters,
+ uint32_t Callsites) {
+
return tryStartContextGivenRoot(FData->getOrAllocateContextRoot(), Guid,
Counters, Callsites);
}
void __llvm_ctx_profile_release_context(FunctionData *FData)
SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
+ const auto *CurrentRoot = __llvm_ctx_profile_current_context_root;
+ if (!CurrentRoot || FData->CtxRoot != CurrentRoot)
+ return;
IsUnderContext = false;
- if (__llvm_ctx_profile_current_context_root) {
- __llvm_ctx_profile_current_context_root = nullptr;
- assert(FData->CtxRoot);
- FData->CtxRoot->Taken.Unlock();
- }
+ assert(FData->CtxRoot);
+ __llvm_ctx_profile_current_context_root = nullptr;
+ FData->CtxRoot->Taken.Unlock();
}
-void __llvm_ctx_profile_start_collection() {
+void __llvm_ctx_profile_start_collection(unsigned AutodetectDuration) {
size_t NumMemUnits = 0;
__sanitizer::GenericScopedLock<__sanitizer::SpinMutex> Lock(
&AllContextsMutex);
@@ -418,12 +435,24 @@ void __llvm_ctx_profile_start_collection() {
resetContextNode(*Root->FirstUnhandledCalleeNode);
__sanitizer::atomic_store_relaxed(&Root->TotalEntries, 0);
}
+ if (AutodetectDuration) {
+ auto *RD = new (__sanitizer::InternalAlloc(sizeof(RootAutoDetector)))
+ RootAutoDetector(AllFunctionsData, RootDetector, AutodetectDuration);
+ RD->start();
+ } else {
+ __sanitizer::Printf("[ctxprof] Initial NumMemUnits: %zu \n", NumMemUnits);
+ }
__sanitizer::atomic_store_relaxed(&ProfilingStarted, true);
- __sanitizer::Printf("[ctxprof] Initial NumMemUnits: %zu \n", NumMemUnits);
}
bool __llvm_ctx_profile_fetch(ProfileWriter &Writer) {
__sanitizer::atomic_store_relaxed(&ProfilingStarted, false);
+ if (auto *RD = getRootDetector()) {
+ __sanitizer::Printf("[ctxprof] Expected the root autodetector to have "
+ "finished well before attempting to fetch a context");
+ RD->join();
+ }
+
__sanitizer::GenericScopedLock<__sanitizer::SpinMutex> Lock(
&AllContextsMutex);
@@ -448,8 +477,9 @@ bool __llvm_ctx_profile_fetch(ProfileWriter &Writer) {
const auto *Pos = reinterpret_cast<const FunctionData *>(
__sanitizer::atomic_load_relaxed(&AllFunctionsData));
for (; Pos; Pos = Pos->Next)
- Writer.writeFlat(Pos->FlatCtx->guid(), Pos->FlatCtx->counters(),
- Pos->FlatCtx->counters_size());
+ if (!Pos->CtxRoot)
+ Writer.writeFlat(Pos->FlatCtx->guid(), Pos->FlatCtx->counters(),
+ Pos->FlatCtx->counters_size());
Writer.endFlatSection();
return true;
}
diff --git a/compiler-rt/lib/ctx_profile/CtxInstrProfiling.h b/compiler-rt/lib/ctx_profile/CtxInstrProfiling.h
index 6326beaa53085..4983f086d230d 100644
--- a/compiler-rt/lib/ctx_profile/CtxInstrProfiling.h
+++ b/compiler-rt/lib/ctx_profile/CtxInstrProfiling.h
@@ -207,7 +207,7 @@ ContextNode *__llvm_ctx_profile_get_context(__ctx_profile::FunctionData *FData,
/// Prepares for collection. Currently this resets counter values but preserves
/// internal context tree structure.
-void __llvm_ctx_profile_start_collection();
+void __llvm_ctx_profile_start_collection(unsigned AutodetectDuration = 0);
/// Completely free allocated memory.
void __llvm_ctx_profile_free();
diff --git a/compiler-rt/lib/ctx_profile/RootAutoDetector.cpp b/compiler-rt/lib/ctx_profile/RootAutoDetector.cpp
index 483c55c25eefe..281ce5e33865a 100644
--- a/compiler-rt/lib/ctx_profile/RootAutoDetector.cpp
+++ b/compiler-rt/lib/ctx_profile/RootAutoDetector.cpp
@@ -8,6 +8,7 @@
#include "RootAutoDetector.h"
+#include "CtxInstrProfiling.h"
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_placement_new.h" // IWYU pragma: keep (DenseMap)
#include <assert.h>
@@ -17,6 +18,99 @@
using namespace __ctx_profile;
template <typename T> using Set = DenseMap<T, bool>;
+namespace __sanitizer {
+void BufferedStackTrace::UnwindImpl(uptr pc, uptr bp, void *context,
+ bool request_fast, u32 max_depth) {
+ // We can't implement the fast variant. The fast variant ends up invoking an
+ // external allocator, because of pthread_attr_getstack. If this happens
+ // during an allocation of the program being instrumented, a non-reentrant
+ // lock may be taken (this was observed). The allocator called by
+ // pthread_attr_getstack will also try to take that lock.
+ UnwindSlow(pc, max_depth);
+}
+} // namespace __sanitizer
+
+RootAutoDetector::PerThreadSamples::PerThreadSamples(RootAutoDetector &Parent) {
+ GenericScopedLock<SpinMutex> L(&Parent.AllSamplesMutex);
+ Parent.AllSamples.PushBack(this);
+}
+
+void RootAutoDetector::start() {
+ atomic_store_relaxed(&Self, reinterpret_cast<uintptr_t>(this));
+ pthread_create(
+ &WorkerThread, nullptr,
+ +[](void *Ctx) -> void * {
+ RootAutoDetector *RAD = reinterpret_cast<RootAutoDetector *>(Ctx);
+ SleepForSeconds(RAD->WaitSeconds);
+ // To avoid holding the AllSamplesMutex, make a snapshot of all the
+ // thread samples collected so far
+ Vector<PerThreadSamples *> SamplesSnapshot;
+ {
+ GenericScopedLock<SpinMutex> M(&RAD->AllSamplesMutex);
+ SamplesSnapshot.Resize(RAD->AllSamples.Size());
+ for (uptr I = 0; I < RAD->AllSamples.Size(); ++I)
+ SamplesSnapshot[I] = RAD->AllSamples[I];
+ }
+ DenseMap<uptr, uint64_t> AllRoots;
+ for (uptr I = 0; I < SamplesSnapshot.Size(); ++I) {
+ GenericScopedLock<SpinMutex>(&SamplesSnapshot[I]->M);
+ SamplesSnapshot[I]->TrieRoot.determineRoots().forEach([&](auto &KVP) {
+ auto [FAddr, Count] = KVP;
+ AllRoots[FAddr] += Count;
+ return true;
+ });
+ }
+ // FIXME: as a next step, establish a minimum relative nr of samples
+ // per root that would qualify it as a root.
+ for (auto *FD = reinterpret_cast<FunctionData *>(
+ atomic_load_relaxed(&RAD->FunctionDataListHead));
+ FD; FD = FD->Next) {
+ if (AllRoots.contains(reinterpret_cast<uptr>(FD->EntryAddress))) {
+ FD->getOrAllocateContextRoot();
+ }
+ }
+ atomic_store_relaxed(&RAD->Self, 0);
+ return nullptr;
+ },
+ this);
+}
+
+void RootAutoDetector::join() { pthread_join(WorkerThread, nullptr); }
+
+void RootAutoDetector::sample() {
+ // tracking reentry in case we want to re-explore fast stack unwind - which
+ // does potentially re-enter the runtime because it calls the instrumented
+ // allocator because of pthread_attr_getstack. See the notes also on
+ // UnwindImpl above.
+ static thread_local bool Entered = false;
+ static thread_local uint64_t Entries = 0;
+ if (Entered || (++Entries % SampleRate))
+ return;
+ Entered = true;
+ collectStack();
+ Entered = false;
+}
+
+void RootAutoDetector::collectStack() {
+ GET_CALLER_PC_BP;
+ BufferedStackTrace CurrentStack;
+ CurrentStack.Unwind(pc, bp, nullptr, false);
+ // 2 stack frames would be very unlikely to mean anything, since at least the
+ // compiler-rt frame - which can't be inlined - should be observable, which
+ // counts as 1; we can be even more aggressive with this number.
+ if (CurrentStack.size <= 2)
+ return;
+ static thread_local PerThreadSamples *ThisThreadSamples =
+ new (__sanitizer::InternalAlloc(sizeof(PerThreadSamples)))
+ PerThreadSamples(*this);
+
+ if (!ThisThreadSamples->M.TryLock())
+ return;
+
+ ThisThreadSamples->TrieRoot.insertStack(CurrentStack);
+ ThisThreadSamples->M.Unlock();
+}
+
uptr PerThreadCallsiteTrie::getFctStartAddr(uptr CallsiteAddress) const {
// this requires --linkopt=-Wl,--export-dynamic
Dl_info Info;
diff --git a/compiler-rt/lib/ctx_profile/RootAutoDetector.h b/compiler-rt/lib/ctx_profile/RootAutoDetector.h
index 85dd5ef1c32d9..5c2abaeb1d0fa 100644
--- a/compiler-rt/lib/ctx_profile/RootAutoDetector.h
+++ b/compiler-rt/lib/ctx_profile/RootAutoDetector.h
@@ -12,6 +12,7 @@
#include "sanitizer_common/sanitizer_dense_map.h"
#include "sanitizer_common/sanitizer_internal_defs.h"
#include "sanitizer_common/sanitizer_stacktrace.h"
+#include "sanitizer_common/sanitizer_vector.h"
#include <pthread.h>
#include <sanitizer/common_interface_defs.h>
@@ -53,5 +54,35 @@ class PerThreadCallsiteTrie {
/// thread, together with the number of samples that included them.
DenseMap<uptr, uint64_t> determineRoots() const;
};
+
+class RootAutoDetector final {
+ static const uint64_t SampleRate = 6113;
+ const unsigned WaitSeconds;
+ pthread_t WorkerThread;
+
+ struct PerThreadSamples {
+ PerThreadSamples(RootAutoDetector &Parent);
+
+ PerThreadCallsiteTrie TrieRoot;
+ SpinMutex M;
+ };
+ SpinMutex AllSamplesMutex;
+ SANITIZER_GUARDED_BY(AllSamplesMutex)
+ Vector<PerThreadSamples *> AllSamples;
+ atomic_uintptr_t &FunctionDataListHead;
+ atomic_uintptr_t &Self;
+ void collectStack();
+
+public:
+ RootAutoDetector(atomic_uintptr_t &FunctionDataListHead,
+ atomic_uintptr_t &Self, unsigned WaitSeconds)
+ : WaitSeconds(WaitSeconds), FunctionDataListHead(FunctionDataListHead),
+ Self(Self) {}
+
+ void sample();
+ void start();
+ void join();
+};
+
} // namespace __ctx_profile
#endif
diff --git a/compiler-rt/test/ctx_profile/TestCases/autodetect-roots.cpp b/compiler-rt/test/ctx_profile/TestCases/autodetect-roots.cpp
new file mode 100644
index 0000000000000..d4d4eb0230fc6
--- /dev/null
+++ b/compiler-rt/test/ctx_profile/TestCases/autodetect-roots.cpp
@@ -0,0 +1,188 @@
+// Root autodetection test for contextual profiling
+//
+// Copy the header defining ContextNode.
+// RUN: mkdir -p %t_include
+// RUN: cp %llvm_src/include/llvm/ProfileData/CtxInstrContextNode.h %t_include/
+//
+// Compile with ctx instrumentation "on". We use -profile-context-root as signal
+// that we want contextual profiling, but we can specify anything there, that
+// won't be matched with any function, and result in the behavior we are aiming
+// for here.
+//
+// RUN: %clangxx %s %ctxprofilelib -I%t_include -O2 -o %t.bin \
+// RUN: -mllvm -profile-context-root="<autodetect>" -g -Wl,-export-dynamic
+//
+// Run the binary, and observe the profile fetch handler's output.
+// RUN %t.bin | FileCheck %s
+
+#include "CtxInstrContextNode.h"
+#include <atomic>
+#include <cstdio>
+#include <iostream>
+#include <thread>
+
+using namespace llvm::ctx_profile;
+extern "C" void __llvm_ctx_profile_start_collection(unsigned);
+extern "C" bool __llvm_ctx_profile_fetch(ProfileWriter &);
+
+// avoid name mangling
+extern "C" {
+__attribute__((noinline)) void anotherFunction() {}
+__attribute__((noinline)) void mock1() {}
+__attribute__((noinline)) void mock2() {}
+__attribute__((noinline)) void someFunction(int I) {
+ if (I % 2)
+ mock1();
+ else
+ mock2();
+ anotherFunction();
+}
+
+// block inlining because the pre-inliner otherwise will inline this - it's
+// too small.
+__attribute__((noinline)) void theRoot() {
+ someFunction(1);
+#pragma nounroll
+ for (auto I = 0; I < 2; ++I) {
+ someFunction(I);
+ }
+ anotherFunction();
+}
+}
+
+class TestProfileWriter : public ProfileWriter {
+ void printProfile(const ContextNode &Node, const std::string &Indent,
+ const std::string &Increment) {
+ std::cout << Indent << "Guid: " << Node.guid() << std::endl;
+ std::cout << Indent << "Entries: " << Node.entrycount() << std::endl;
+ std::cout << Indent << Node.counters_size() << " counters and "
+ << Node.callsites_size() << " callsites" << std::endl;
+ std::cout << Indent << "Counter values: ";
+ for (uint32_t I = 0U; I < Node.counters_size(); ++I)
+ std::cout << Node.counters()[I] << " ";
+ std::cout << std::endl;
+ for (uint32_t I = 0U; I < Node.callsites_size(); ++I)
+ for (const auto *N = Node.subContexts()[I]; N; N = N->next()) {
+ std::cout << Indent << "At Index " << I << ":" << std::endl;
+ printProfile(*N, Indent + Increment, Increment);
+ }
+ }
+
+ void startContextSection() override {
+ std::cout << "Entered Context Section" << std::endl;
+ }
+
+ void endContextSection() override {
+ std::cout << "Exited Context Section" << std::endl;
+ }
+
+ void writeContextual(const ContextNode &RootNode,
+ const ContextNode *Unhandled,
+ uint64_t EntryCount) override {
+ std::cout << "Entering Root " << RootNode.guid()
+ << " with total entry count " << EntryCount << std::endl;
+ for (const auto *P = Unhandled; P; P = P->next())
+ std::cout << "Unhandled GUID: " << P->guid() << " entered "
+ << P->entrycount() << " times" << std::endl;
+ printProfile(RootNode, " ", " ");
+ }
+
+ void startFlatSection() override {
+ std::cout << "Entered Flat Section" << std::endl;
+ }
+
+ void writeFlat(GUID Guid, const uint64_t *Buffer,
+ size_t BufferSize) override {
+ std::cout << "Flat: " << Guid << " " << Buffer[0];
+ for (size_t I = 1U; I < BufferSize; ++I)
+ std::cout << "," << Buffer[I];
+ std::cout << std::endl;
+ };
+
+ void endFlatSection() override {
+ std::cout << "Exited Flat Section" << std::endl;
+ }
+};
+
+// Guid:3950394326069683896 is anotherFunction
+// Guid:6759619411192316602 is someFunction
+// These are expected to be the auto-detected roots. This is because we cannot
+// discerne (with the current aut...
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/133147
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