1//===- xray-stacks.cpp: XRay Function Call Stack Accounting ---------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements stack-based accounting. It takes XRay traces, and
10// collates statistics across these traces to show a breakdown of time spent
11// at various points of the stack to provide insight into which functions
12// spend the most time in terms of a call stack. We provide a few
13// sorting/filtering options for zero'ing in on the useful stacks.
14//
15//===----------------------------------------------------------------------===//
16
17#include <forward_list>
18#include <numeric>
19
20#include "func-id-helper.h"
21#include "trie-node.h"
22#include "xray-registry.h"
23#include "llvm/ADT/StringExtras.h"
24#include "llvm/Support/CommandLine.h"
25#include "llvm/Support/Errc.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/FormatAdapters.h"
28#include "llvm/Support/FormatVariadic.h"
29#include "llvm/XRay/Graph.h"
30#include "llvm/XRay/InstrumentationMap.h"
31#include "llvm/XRay/Trace.h"
32
33using namespace llvm;
34using namespace llvm::xray;
35
36static cl::SubCommand Stack("stack", "Call stack accounting");
37static cl::list<std::string> StackInputs(cl::Positional,
38 cl::desc("<xray trace>"), cl::Required,
39 cl::sub(Stack), cl::OneOrMore);
40
41static cl::opt<bool>
42 StackKeepGoing("keep-going", cl::desc("Keep going on errors encountered"),
43 cl::sub(Stack), cl::init(Val: false));
44static cl::alias StackKeepGoing2("k", cl::aliasopt(StackKeepGoing),
45 cl::desc("Alias for -keep-going"));
46
47// TODO: Does there need to be an option to deduce tail or sibling calls?
48
49static cl::opt<std::string> StacksInstrMap(
50 "instr_map",
51 cl::desc("instrumentation map used to identify function ids. "
52 "Currently supports elf file instrumentation maps."),
53 cl::sub(Stack), cl::init(Val: ""));
54static cl::alias StacksInstrMap2("m", cl::aliasopt(StacksInstrMap),
55 cl::desc("Alias for -instr_map"));
56
57static cl::opt<bool>
58 SeparateThreadStacks("per-thread-stacks",
59 cl::desc("Report top stacks within each thread id"),
60 cl::sub(Stack), cl::init(Val: false));
61
62static cl::opt<bool>
63 AggregateThreads("aggregate-threads",
64 cl::desc("Aggregate stack times across threads"),
65 cl::sub(Stack), cl::init(Val: false));
66
67static cl::opt<bool>
68 DumpAllStacks("all-stacks",
69 cl::desc("Dump sum of timings for all stacks. "
70 "By default separates stacks per-thread."),
71 cl::sub(Stack), cl::init(Val: false));
72static cl::alias DumpAllStacksShort("all", cl::aliasopt(DumpAllStacks),
73 cl::desc("Alias for -all-stacks"));
74
75// TODO(kpw): Add other interesting formats. Perhaps chrome trace viewer format
76// possibly with aggregations or just a linear trace of timings.
77enum StackOutputFormat { HUMAN, FLAMETOOL };
78
79static cl::opt<StackOutputFormat> StacksOutputFormat(
80 "stack-format",
81 cl::desc("The format that output stacks should be "
82 "output in. Only applies with all-stacks."),
83 cl::values(
84 clEnumValN(HUMAN, "human",
85 "Human readable output. Only valid without -all-stacks."),
86 clEnumValN(FLAMETOOL, "flame",
87 "Format consumable by Brendan Gregg's FlameGraph tool. "
88 "Only valid with -all-stacks.")),
89 cl::sub(Stack), cl::init(Val: HUMAN));
90
91// Types of values for each stack in a CallTrie.
92enum class AggregationType {
93 TOTAL_TIME, // The total time spent in a stack and its callees.
94 INVOCATION_COUNT // The number of times the stack was invoked.
95};
96
97static cl::opt<AggregationType> RequestedAggregation(
98 "aggregation-type",
99 cl::desc("The type of aggregation to do on call stacks."),
100 cl::values(
101 clEnumValN(
102 AggregationType::TOTAL_TIME, "time",
103 "Capture the total time spent in an all invocations of a stack."),
104 clEnumValN(AggregationType::INVOCATION_COUNT, "count",
105 "Capture the number of times a stack was invoked. "
106 "In flamegraph mode, this count also includes invocations "
107 "of all callees.")),
108 cl::sub(Stack), cl::init(Val: AggregationType::TOTAL_TIME));
109
110/// A helper struct to work with formatv and XRayRecords. Makes it easier to
111/// use instrumentation map names or addresses in formatted output.
112struct format_xray_record : public FormatAdapter<XRayRecord> {
113 explicit format_xray_record(XRayRecord record,
114 const FuncIdConversionHelper &conv)
115 : FormatAdapter<XRayRecord>(std::move(record)), Converter(&conv) {}
116 void format(raw_ostream &Stream, StringRef Style) override {
117 Stream << formatv(
118 Fmt: "{FuncId: \"{0}\", ThreadId: \"{1}\", RecordType: \"{2}\"}",
119 Vals: Converter->SymbolOrNumber(FuncId: Item.FuncId), Vals&: Item.TId,
120 Vals: DecodeRecordType(recordType: Item.RecordType));
121 }
122
123private:
124 Twine DecodeRecordType(uint16_t recordType) {
125 switch (recordType) {
126 case 0:
127 return Twine("Fn Entry");
128 case 1:
129 return Twine("Fn Exit");
130 default:
131 // TODO: Add Tail exit when it is added to llvm/XRay/XRayRecord.h
132 return Twine("Unknown");
133 }
134 }
135
136 const FuncIdConversionHelper *Converter;
137};
138
139/// The stack command will take a set of XRay traces as arguments, and collects
140/// information about the stacks of instrumented functions that appear in the
141/// traces. We track the following pieces of information:
142///
143/// - Total time: amount of time/cycles accounted for in the traces.
144/// - Stack count: number of times a specific stack appears in the
145/// traces. Only instrumented functions show up in stacks.
146/// - Cumulative stack time: amount of time spent in a stack accumulated
147/// across the invocations in the traces.
148/// - Cumulative local time: amount of time spent in each instrumented
149/// function showing up in a specific stack, accumulated across the traces.
150///
151/// Example output for the kind of data we'd like to provide looks like the
152/// following:
153///
154/// Total time: 3.33234 s
155/// Stack ID: ...
156/// Stack Count: 2093
157/// # Function Local Time (%) Stack Time (%)
158/// 0 main 2.34 ms 0.07% 3.33234 s 100%
159/// 1 foo() 3.30000 s 99.02% 3.33 s 99.92%
160/// 2 bar() 30 ms 0.90% 30 ms 0.90%
161///
162/// We can also show distributions of the function call durations with
163/// statistics at each level of the stack. This works by doing the following
164/// algorithm:
165///
166/// 1. When unwinding, record the duration of each unwound function associated
167/// with the path up to which the unwinding stops. For example:
168///
169/// Step Duration (? means has start time)
170///
171/// push a <start time> a = ?
172/// push b <start time> a = ?, a->b = ?
173/// push c <start time> a = ?, a->b = ?, a->b->c = ?
174/// pop c <end time> a = ?, a->b = ?, emit duration(a->b->c)
175/// pop b <end time> a = ?, emit duration(a->b)
176/// push c <start time> a = ?, a->c = ?
177/// pop c <end time> a = ?, emit duration(a->c)
178/// pop a <end time> emit duration(a)
179///
180/// 2. We then account for the various stacks we've collected, and for each of
181/// them will have measurements that look like the following (continuing
182/// with the above simple example):
183///
184/// c : [<id("a->b->c"), [durations]>, <id("a->c"), [durations]>]
185/// b : [<id("a->b"), [durations]>]
186/// a : [<id("a"), [durations]>]
187///
188/// This allows us to compute, for each stack id, and each function that
189/// shows up in the stack, some important statistics like:
190///
191/// - median
192/// - 99th percentile
193/// - mean + stddev
194/// - count
195///
196/// 3. For cases where we don't have durations for some of the higher levels
197/// of the stack (perhaps instrumentation wasn't activated when the stack was
198/// entered), we can mark them appropriately.
199///
200/// Computing this data also allows us to implement lookup by call stack nodes,
201/// so that we can find functions that show up in multiple stack traces and
202/// show the statistical properties of that function in various contexts. We
203/// can compute information similar to the following:
204///
205/// Function: 'c'
206/// Stacks: 2 / 2
207/// Stack ID: ...
208/// Stack Count: ...
209/// # Function ...
210/// 0 a ...
211/// 1 b ...
212/// 2 c ...
213///
214/// Stack ID: ...
215/// Stack Count: ...
216/// # Function ...
217/// 0 a ...
218/// 1 c ...
219/// ----------------...
220///
221/// Function: 'b'
222/// Stacks: 1 / 2
223/// Stack ID: ...
224/// Stack Count: ...
225/// # Function ...
226/// 0 a ...
227/// 1 b ...
228/// 2 c ...
229///
230///
231/// To do this we require a Trie data structure that will allow us to represent
232/// all the call stacks of instrumented functions in an easily traversible
233/// manner when we do the aggregations and lookups. For instrumented call
234/// sequences like the following:
235///
236/// a()
237/// b()
238/// c()
239/// d()
240/// c()
241///
242/// We will have a representation like so:
243///
244/// a -> b -> c
245/// | |
246/// | +--> d
247/// |
248/// +--> c
249///
250/// We maintain a sequence of durations on the leaves and in the internal nodes
251/// as we go through and process every record from the XRay trace. We also
252/// maintain an index of unique functions, and provide a means of iterating
253/// through all the instrumented call stacks which we know about.
254
255namespace {
256struct StackDuration {
257 llvm::SmallVector<int64_t, 4> TerminalDurations;
258 llvm::SmallVector<int64_t, 4> IntermediateDurations;
259};
260} // namespace
261
262static StackDuration mergeStackDuration(const StackDuration &Left,
263 const StackDuration &Right) {
264 StackDuration Data{};
265 Data.TerminalDurations.reserve(N: Left.TerminalDurations.size() +
266 Right.TerminalDurations.size());
267 Data.IntermediateDurations.reserve(N: Left.IntermediateDurations.size() +
268 Right.IntermediateDurations.size());
269 // Aggregate the durations.
270 llvm::append_range(C&: Data.TerminalDurations, R: Left.TerminalDurations);
271 llvm::append_range(C&: Data.TerminalDurations, R: Right.TerminalDurations);
272
273 llvm::append_range(C&: Data.IntermediateDurations, R: Left.IntermediateDurations);
274 llvm::append_range(C&: Data.IntermediateDurations, R: Right.IntermediateDurations);
275 return Data;
276}
277
278using StackTrieNode = TrieNode<StackDuration>;
279
280template <AggregationType AggType>
281static std::size_t GetValueForStack(const StackTrieNode *Node);
282
283// When computing total time spent in a stack, we're adding the timings from
284// its callees and the timings from when it was a leaf.
285template <>
286std::size_t
287GetValueForStack<AggregationType::TOTAL_TIME>(const StackTrieNode *Node) {
288 auto TopSum = std::accumulate(first: Node->ExtraData.TerminalDurations.begin(),
289 last: Node->ExtraData.TerminalDurations.end(), init: 0uLL);
290 return std::accumulate(first: Node->ExtraData.IntermediateDurations.begin(),
291 last: Node->ExtraData.IntermediateDurations.end(), init: TopSum);
292}
293
294// Calculates how many times a function was invoked.
295// TODO: Hook up option to produce stacks
296template <>
297std::size_t
298GetValueForStack<AggregationType::INVOCATION_COUNT>(const StackTrieNode *Node) {
299 return Node->ExtraData.TerminalDurations.size() +
300 Node->ExtraData.IntermediateDurations.size();
301}
302
303// Make sure there are implementations for each enum value.
304template <AggregationType T> struct DependentFalseType : std::false_type {};
305
306template <AggregationType AggType>
307std::size_t GetValueForStack(const StackTrieNode *Node) {
308 static_assert(DependentFalseType<AggType>::value,
309 "No implementation found for aggregation type provided.");
310 return 0;
311}
312
313class StackTrie {
314 // Avoid the magic number of 4 propagated through the code with an alias.
315 // We use this SmallVector to track the root nodes in a call graph.
316 using RootVector = SmallVector<StackTrieNode *, 4>;
317
318 // We maintain pointers to the roots of the tries we see.
319 DenseMap<uint32_t, RootVector> Roots;
320
321 // We make sure all the nodes are accounted for in this list.
322 std::forward_list<StackTrieNode> NodeStore;
323
324 // A map of thread ids to pairs call stack trie nodes and their start times.
325 DenseMap<uint32_t, SmallVector<std::pair<StackTrieNode *, uint64_t>, 8>>
326 ThreadStackMap;
327
328 StackTrieNode *createTrieNode(uint32_t ThreadId, int32_t FuncId,
329 StackTrieNode *Parent) {
330 NodeStore.push_front(val: StackTrieNode{.FuncId: FuncId, .Parent: Parent, .Callees: {}, .ExtraData: {.TerminalDurations: {}, .IntermediateDurations: {}}});
331 auto I = NodeStore.begin();
332 auto *Node = &*I;
333 if (!Parent)
334 Roots[ThreadId].push_back(Elt: Node);
335 return Node;
336 }
337
338 StackTrieNode *findRootNode(uint32_t ThreadId, int32_t FuncId) {
339 const auto &RootsByThread = Roots[ThreadId];
340 auto I = find_if(Range: RootsByThread,
341 P: [&](StackTrieNode *N) { return N->FuncId == FuncId; });
342 return (I == RootsByThread.end()) ? nullptr : *I;
343 }
344
345public:
346 enum class AccountRecordStatus {
347 OK, // Successfully processed
348 ENTRY_NOT_FOUND, // An exit record had no matching call stack entry
349 UNKNOWN_RECORD_TYPE
350 };
351
352 struct AccountRecordState {
353 // We keep track of whether the call stack is currently unwinding.
354 bool wasLastRecordExit;
355
356 static AccountRecordState CreateInitialState() { return {.wasLastRecordExit: false}; }
357 };
358
359 AccountRecordStatus accountRecord(const XRayRecord &R,
360 AccountRecordState *state) {
361 auto &TS = ThreadStackMap[R.TId];
362 switch (R.Type) {
363 case RecordTypes::CUSTOM_EVENT:
364 case RecordTypes::TYPED_EVENT:
365 return AccountRecordStatus::OK;
366 case RecordTypes::ENTER:
367 case RecordTypes::ENTER_ARG: {
368 state->wasLastRecordExit = false;
369 // When we encounter a new function entry, we want to record the TSC for
370 // that entry, and the function id. Before doing so we check the top of
371 // the stack to see if there are callees that already represent this
372 // function.
373 if (TS.empty()) {
374 auto *Root = findRootNode(ThreadId: R.TId, FuncId: R.FuncId);
375 TS.emplace_back(Args: Root ? Root : createTrieNode(ThreadId: R.TId, FuncId: R.FuncId, Parent: nullptr),
376 Args: R.TSC);
377 return AccountRecordStatus::OK;
378 }
379
380 auto &Top = TS.back();
381 auto I = find_if(Range&: Top.first->Callees,
382 P: [&](StackTrieNode *N) { return N->FuncId == R.FuncId; });
383 if (I == Top.first->Callees.end()) {
384 // We didn't find the callee in the stack trie, so we're going to
385 // add to the stack then set up the pointers properly.
386 auto N = createTrieNode(ThreadId: R.TId, FuncId: R.FuncId, Parent: Top.first);
387 Top.first->Callees.emplace_back(Args&: N);
388
389 // Top may be invalidated after this statement.
390 TS.emplace_back(Args&: N, Args: R.TSC);
391 } else {
392 // We found the callee in the stack trie, so we'll use that pointer
393 // instead, add it to the stack associated with the TSC.
394 TS.emplace_back(Args&: *I, Args: R.TSC);
395 }
396 return AccountRecordStatus::OK;
397 }
398 case RecordTypes::EXIT:
399 case RecordTypes::TAIL_EXIT: {
400 bool wasLastRecordExit = state->wasLastRecordExit;
401 state->wasLastRecordExit = true;
402 // The exit case is more interesting, since we want to be able to deduce
403 // missing exit records. To do that properly, we need to look up the stack
404 // and see whether the exit record matches any of the entry records. If it
405 // does match, we attempt to record the durations as we pop the stack to
406 // where we see the parent.
407 if (TS.empty()) {
408 // Short circuit, and say we can't find it.
409
410 return AccountRecordStatus::ENTRY_NOT_FOUND;
411 }
412
413 auto FunctionEntryMatch = find_if(
414 Range: reverse(C&: TS), P: [&](const std::pair<StackTrieNode *, uint64_t> &E) {
415 return E.first->FuncId == R.FuncId;
416 });
417 auto status = AccountRecordStatus::OK;
418 if (FunctionEntryMatch == TS.rend()) {
419 status = AccountRecordStatus::ENTRY_NOT_FOUND;
420 } else {
421 // Account for offset of 1 between reverse and forward iterators. We
422 // want the forward iterator to include the function that is exited.
423 ++FunctionEntryMatch;
424 }
425 auto I = FunctionEntryMatch.base();
426 for (auto &E : make_range(x: I, y: TS.end() - 1))
427 E.first->ExtraData.IntermediateDurations.push_back(
428 Elt: std::max(a: E.second, b: R.TSC) - std::min(a: E.second, b: R.TSC));
429 auto &Deepest = TS.back();
430 if (wasLastRecordExit)
431 Deepest.first->ExtraData.IntermediateDurations.push_back(
432 Elt: std::max(a: Deepest.second, b: R.TSC) - std::min(a: Deepest.second, b: R.TSC));
433 else
434 Deepest.first->ExtraData.TerminalDurations.push_back(
435 Elt: std::max(a: Deepest.second, b: R.TSC) - std::min(a: Deepest.second, b: R.TSC));
436 TS.erase(CS: I, CE: TS.end());
437 return status;
438 }
439 }
440 return AccountRecordStatus::UNKNOWN_RECORD_TYPE;
441 }
442
443 bool isEmpty() const { return Roots.empty(); }
444
445 void printStack(raw_ostream &OS, const StackTrieNode *Top,
446 FuncIdConversionHelper &FN) {
447 // Traverse the pointers up to the parent, noting the sums, then print
448 // in reverse order (callers at top, callees down bottom).
449 SmallVector<const StackTrieNode *, 8> CurrentStack;
450 for (auto *F = Top; F != nullptr; F = F->Parent)
451 CurrentStack.push_back(Elt: F);
452 int Level = 0;
453 OS << formatv(Fmt: "{0,-5} {1,-60} {2,+12} {3,+16}\n", Vals: "lvl", Vals: "function",
454 Vals: "count", Vals: "sum");
455 for (auto *F : reverse(C: drop_begin(RangeOrContainer&: CurrentStack))) {
456 auto Sum = std::accumulate(first: F->ExtraData.IntermediateDurations.begin(),
457 last: F->ExtraData.IntermediateDurations.end(), init: 0LL);
458 auto FuncId = FN.SymbolOrNumber(FuncId: F->FuncId);
459 OS << formatv(Fmt: "#{0,-4} {1,-60} {2,+12} {3,+16}\n", Vals: Level++,
460 Vals: FuncId.size() > 60 ? FuncId.substr(pos: 0, n: 57) + "..." : FuncId,
461 Vals: F->ExtraData.IntermediateDurations.size(), Vals&: Sum);
462 }
463 auto *Leaf = *CurrentStack.begin();
464 auto LeafSum =
465 std::accumulate(first: Leaf->ExtraData.TerminalDurations.begin(),
466 last: Leaf->ExtraData.TerminalDurations.end(), init: 0LL);
467 auto LeafFuncId = FN.SymbolOrNumber(FuncId: Leaf->FuncId);
468 OS << formatv(Fmt: "#{0,-4} {1,-60} {2,+12} {3,+16}\n", Vals: Level++,
469 Vals: LeafFuncId.size() > 60 ? LeafFuncId.substr(pos: 0, n: 57) + "..."
470 : LeafFuncId,
471 Vals: Leaf->ExtraData.TerminalDurations.size(), Vals&: LeafSum);
472 OS << "\n";
473 }
474
475 /// Prints top stacks for each thread.
476 void printPerThread(raw_ostream &OS, FuncIdConversionHelper &FN) {
477 for (const auto &iter : Roots) {
478 OS << "Thread " << iter.first << ":\n";
479 print(OS, FN, RootValues: iter.second);
480 OS << "\n";
481 }
482 }
483
484 /// Prints timing sums for each stack in each threads.
485 template <AggregationType AggType>
486 void printAllPerThread(raw_ostream &OS, FuncIdConversionHelper &FN,
487 StackOutputFormat format) {
488 for (const auto &iter : Roots)
489 printAll<AggType>(OS, FN, iter.second, iter.first, true);
490 }
491
492 /// Prints top stacks from looking at all the leaves and ignoring thread IDs.
493 /// Stacks that consist of the same function IDs but were called in different
494 /// thread IDs are not considered unique in this printout.
495 void printIgnoringThreads(raw_ostream &OS, FuncIdConversionHelper &FN) {
496 RootVector RootValues;
497
498 for (const auto &RootNodeRange : make_second_range(c&: Roots))
499 llvm::append_range(C&: RootValues, R: RootNodeRange);
500
501 print(OS, FN, RootValues);
502 }
503
504 /// Creates a merged list of Tries for unique stacks that disregards their
505 /// thread IDs.
506 RootVector mergeAcrossThreads(std::forward_list<StackTrieNode> &NodeStore) {
507 RootVector MergedByThreadRoots;
508 for (const auto &MapIter : Roots) {
509 const auto &RootNodeVector = MapIter.second;
510 for (auto *Node : RootNodeVector) {
511 auto MaybeFoundIter =
512 find_if(Range&: MergedByThreadRoots, P: [Node](StackTrieNode *elem) {
513 return Node->FuncId == elem->FuncId;
514 });
515 if (MaybeFoundIter == MergedByThreadRoots.end()) {
516 MergedByThreadRoots.push_back(Elt: Node);
517 } else {
518 MergedByThreadRoots.push_back(Elt: mergeTrieNodes(
519 Left: **MaybeFoundIter, Right: *Node, NewParent: nullptr, NodeStore, MergeCallable&: mergeStackDuration));
520 MergedByThreadRoots.erase(CI: MaybeFoundIter);
521 }
522 }
523 }
524 return MergedByThreadRoots;
525 }
526
527 /// Print timing sums for all stacks merged by Thread ID.
528 template <AggregationType AggType>
529 void printAllAggregatingThreads(raw_ostream &OS, FuncIdConversionHelper &FN,
530 StackOutputFormat format) {
531 std::forward_list<StackTrieNode> AggregatedNodeStore;
532 RootVector MergedByThreadRoots = mergeAcrossThreads(NodeStore&: AggregatedNodeStore);
533 bool reportThreadId = false;
534 printAll<AggType>(OS, FN, MergedByThreadRoots,
535 /*threadId*/ 0, reportThreadId);
536 }
537
538 /// Merges the trie by thread id before printing top stacks.
539 void printAggregatingThreads(raw_ostream &OS, FuncIdConversionHelper &FN) {
540 std::forward_list<StackTrieNode> AggregatedNodeStore;
541 RootVector MergedByThreadRoots = mergeAcrossThreads(NodeStore&: AggregatedNodeStore);
542 print(OS, FN, RootValues: MergedByThreadRoots);
543 }
544
545 // TODO: Add a format option when more than one are supported.
546 template <AggregationType AggType>
547 void printAll(raw_ostream &OS, FuncIdConversionHelper &FN,
548 RootVector RootValues, uint32_t ThreadId, bool ReportThread) {
549 SmallVector<const StackTrieNode *, 16> S;
550 for (const auto *N : RootValues) {
551 S.clear();
552 S.push_back(Elt: N);
553 while (!S.empty()) {
554 auto *Top = S.pop_back_val();
555 printSingleStack<AggType>(OS, FN, ReportThread, ThreadId, Top);
556 llvm::append_range(C&: S, R: Top->Callees);
557 }
558 }
559 }
560
561 /// Prints values for stacks in a format consumable for the flamegraph.pl
562 /// tool. This is a line based format that lists each level in the stack
563 /// hierarchy in a semicolon delimited form followed by a space and a numeric
564 /// value. If breaking down by thread, the thread ID will be added as the
565 /// root level of the stack.
566 template <AggregationType AggType>
567 void printSingleStack(raw_ostream &OS, FuncIdConversionHelper &Converter,
568 bool ReportThread, uint32_t ThreadId,
569 const StackTrieNode *Node) {
570 if (ReportThread)
571 OS << "thread_" << ThreadId << ";";
572 SmallVector<const StackTrieNode *, 5> lineage{};
573 lineage.push_back(Elt: Node);
574 while (lineage.back()->Parent != nullptr)
575 lineage.push_back(Elt: lineage.back()->Parent);
576 while (!lineage.empty()) {
577 OS << Converter.SymbolOrNumber(FuncId: lineage.back()->FuncId) << ";";
578 lineage.pop_back();
579 }
580 OS << " " << GetValueForStack<AggType>(Node) << "\n";
581 }
582
583 void print(raw_ostream &OS, FuncIdConversionHelper &FN,
584 RootVector RootValues) {
585 // Go through each of the roots, and traverse the call stack, producing the
586 // aggregates as you go along. Remember these aggregates and stacks, and
587 // show summary statistics about:
588 //
589 // - Total number of unique stacks
590 // - Top 10 stacks by count
591 // - Top 10 stacks by aggregate duration
592 SmallVector<std::pair<const StackTrieNode *, uint64_t>, 11>
593 TopStacksByCount;
594 SmallVector<std::pair<const StackTrieNode *, uint64_t>, 11> TopStacksBySum;
595 auto greater_second =
596 [](const std::pair<const StackTrieNode *, uint64_t> &A,
597 const std::pair<const StackTrieNode *, uint64_t> &B) {
598 return A.second > B.second;
599 };
600 uint64_t UniqueStacks = 0;
601 for (const auto *N : RootValues) {
602 SmallVector<const StackTrieNode *, 16> S;
603 S.emplace_back(Args&: N);
604
605 while (!S.empty()) {
606 auto *Top = S.pop_back_val();
607
608 // We only start printing the stack (by walking up the parent pointers)
609 // when we get to a leaf function.
610 if (!Top->ExtraData.TerminalDurations.empty()) {
611 ++UniqueStacks;
612 auto TopSum =
613 std::accumulate(first: Top->ExtraData.TerminalDurations.begin(),
614 last: Top->ExtraData.TerminalDurations.end(), init: 0uLL);
615 {
616 auto E = std::make_pair(x&: Top, y&: TopSum);
617 TopStacksBySum.insert(
618 I: llvm::lower_bound(Range&: TopStacksBySum, Value&: E, C: greater_second), Elt: E);
619 if (TopStacksBySum.size() == 11)
620 TopStacksBySum.pop_back();
621 }
622 {
623 auto E =
624 std::make_pair(x&: Top, y: Top->ExtraData.TerminalDurations.size());
625 TopStacksByCount.insert(
626 I: llvm::lower_bound(Range&: TopStacksByCount, Value&: E, C: greater_second), Elt: E);
627 if (TopStacksByCount.size() == 11)
628 TopStacksByCount.pop_back();
629 }
630 }
631 llvm::append_range(C&: S, R: Top->Callees);
632 }
633 }
634
635 // Now print the statistics in the end.
636 OS << "\n";
637 OS << "Unique Stacks: " << UniqueStacks << "\n";
638 OS << "Top 10 Stacks by leaf sum:\n\n";
639 for (const auto &P : TopStacksBySum) {
640 OS << "Sum: " << P.second << "\n";
641 printStack(OS, Top: P.first, FN);
642 }
643 OS << "\n";
644 OS << "Top 10 Stacks by leaf count:\n\n";
645 for (const auto &P : TopStacksByCount) {
646 OS << "Count: " << P.second << "\n";
647 printStack(OS, Top: P.first, FN);
648 }
649 OS << "\n";
650 }
651};
652
653static std::string CreateErrorMessage(StackTrie::AccountRecordStatus Error,
654 const XRayRecord &Record,
655 const FuncIdConversionHelper &Converter) {
656 switch (Error) {
657 case StackTrie::AccountRecordStatus::ENTRY_NOT_FOUND:
658 return std::string(
659 formatv(Fmt: "Found record {0} with no matching function entry\n",
660 Vals: format_xray_record(Record, Converter)));
661 default:
662 return std::string(formatv(Fmt: "Unknown error type for record {0}\n",
663 Vals: format_xray_record(Record, Converter)));
664 }
665}
666
667static CommandRegistration Unused(&Stack, []() -> Error {
668 // Load each file provided as a command-line argument. For each one of them
669 // account to a single StackTrie, and just print the whole trie for now.
670 StackTrie ST;
671 InstrumentationMap Map;
672 if (!StacksInstrMap.empty()) {
673 auto InstrumentationMapOrError = loadInstrumentationMap(Filename: StacksInstrMap);
674 if (!InstrumentationMapOrError)
675 return joinErrors(
676 E1: make_error<StringError>(
677 Args: Twine("Cannot open instrumentation map: ") + StacksInstrMap,
678 Args: std::make_error_code(e: std::errc::invalid_argument)),
679 E2: InstrumentationMapOrError.takeError());
680 Map = std::move(*InstrumentationMapOrError);
681 }
682
683 if (SeparateThreadStacks && AggregateThreads)
684 return make_error<StringError>(
685 Args: Twine("Can't specify options for per thread reporting and reporting "
686 "that aggregates threads."),
687 Args: std::make_error_code(e: std::errc::invalid_argument));
688
689 if (!DumpAllStacks && StacksOutputFormat != HUMAN)
690 return make_error<StringError>(
691 Args: Twine("Can't specify a non-human format without -all-stacks."),
692 Args: std::make_error_code(e: std::errc::invalid_argument));
693
694 if (DumpAllStacks && StacksOutputFormat == HUMAN)
695 return make_error<StringError>(
696 Args: Twine("You must specify a non-human format when reporting with "
697 "-all-stacks."),
698 Args: std::make_error_code(e: std::errc::invalid_argument));
699
700 symbolize::LLVMSymbolizer Symbolizer;
701 FuncIdConversionHelper FuncIdHelper(StacksInstrMap, Symbolizer,
702 Map.getFunctionAddresses());
703 // TODO: Someday, support output to files instead of just directly to
704 // standard output.
705 for (const auto &Filename : StackInputs) {
706 auto TraceOrErr = loadTraceFile(Filename);
707 if (!TraceOrErr) {
708 if (!StackKeepGoing)
709 return joinErrors(
710 E1: make_error<StringError>(
711 Args: Twine("Failed loading input file '") + Filename + "'",
712 Args: std::make_error_code(e: std::errc::invalid_argument)),
713 E2: TraceOrErr.takeError());
714 logAllUnhandledErrors(E: TraceOrErr.takeError(), OS&: errs());
715 continue;
716 }
717 auto &T = *TraceOrErr;
718 StackTrie::AccountRecordState AccountRecordState =
719 StackTrie::AccountRecordState::CreateInitialState();
720 for (const auto &Record : T) {
721 auto error = ST.accountRecord(R: Record, state: &AccountRecordState);
722 if (error != StackTrie::AccountRecordStatus::OK) {
723 if (!StackKeepGoing)
724 return make_error<StringError>(
725 Args: CreateErrorMessage(Error: error, Record, Converter: FuncIdHelper),
726 Args: make_error_code(E: errc::illegal_byte_sequence));
727 errs() << CreateErrorMessage(Error: error, Record, Converter: FuncIdHelper);
728 }
729 }
730 }
731 if (ST.isEmpty()) {
732 return make_error<StringError>(
733 Args: "No instrumented calls were accounted in the input file.",
734 Args: make_error_code(E: errc::result_out_of_range));
735 }
736
737 // Report the stacks in a long form mode for another tool to analyze.
738 if (DumpAllStacks) {
739 if (AggregateThreads) {
740 switch (RequestedAggregation) {
741 case AggregationType::TOTAL_TIME:
742 ST.printAllAggregatingThreads<AggregationType::TOTAL_TIME>(
743 OS&: outs(), FN&: FuncIdHelper, format: StacksOutputFormat);
744 break;
745 case AggregationType::INVOCATION_COUNT:
746 ST.printAllAggregatingThreads<AggregationType::INVOCATION_COUNT>(
747 OS&: outs(), FN&: FuncIdHelper, format: StacksOutputFormat);
748 break;
749 }
750 } else {
751 switch (RequestedAggregation) {
752 case AggregationType::TOTAL_TIME:
753 ST.printAllPerThread<AggregationType::TOTAL_TIME>(OS&: outs(), FN&: FuncIdHelper,
754 format: StacksOutputFormat);
755 break;
756 case AggregationType::INVOCATION_COUNT:
757 ST.printAllPerThread<AggregationType::INVOCATION_COUNT>(
758 OS&: outs(), FN&: FuncIdHelper, format: StacksOutputFormat);
759 break;
760 }
761 }
762 return Error::success();
763 }
764
765 // We're only outputting top stacks.
766 if (AggregateThreads) {
767 ST.printAggregatingThreads(OS&: outs(), FN&: FuncIdHelper);
768 } else if (SeparateThreadStacks) {
769 ST.printPerThread(OS&: outs(), FN&: FuncIdHelper);
770 } else {
771 ST.printIgnoringThreads(OS&: outs(), FN&: FuncIdHelper);
772 }
773 return Error::success();
774});
775