[llvm] Add initial support for SPE brstack format (PR #129231)

[Paschalis Mpeis via llvm-commits]

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@@ -0,0 +1,144 @@
+//===- bolt/unittests/Profile/PerfSpeEvents.cpp ---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifdef AARCH64_AVAILABLE
+
+#include "bolt/Core/BinaryContext.h"
+#include "bolt/Profile/DataAggregator.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/TargetSelect.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace llvm::bolt;
+using namespace llvm::object;
+using namespace llvm::ELF;
+
+namespace opts {
+extern cl::opt<std::string> ReadPerfEvents;
+extern cl::opt<bool> ArmSPE;
+} // namespace opts
+
+namespace llvm {
+namespace bolt {
+
+/// Perform checks on perf SPE branch events combined with other SPE or perf
+/// events.
+struct PerfSpeEventsTestHelper : public testing::Test {
+  void SetUp() override {
+    initalizeLLVM();
+    prepareElf();
+    initializeBOLT();
+  }
+
+protected:
+  void initalizeLLVM() {
+    llvm::InitializeAllTargetInfos();
+    llvm::InitializeAllTargetMCs();
+    llvm::InitializeAllAsmParsers();
+    llvm::InitializeAllDisassemblers();
+    llvm::InitializeAllTargets();
+    llvm::InitializeAllAsmPrinters();
+  }
+
+  void prepareElf() {
+    memcpy(ElfBuf, "\177ELF", 4);
+    ELF64LE::Ehdr *EHdr = reinterpret_cast<typename ELF64LE::Ehdr *>(ElfBuf);
+    EHdr->e_ident[llvm::ELF::EI_CLASS] = llvm::ELF::ELFCLASS64;
+    EHdr->e_ident[llvm::ELF::EI_DATA] = llvm::ELF::ELFDATA2LSB;
+    EHdr->e_machine = llvm::ELF::EM_AARCH64;
+    MemoryBufferRef Source(StringRef(ElfBuf, sizeof(ElfBuf)), "ELF");
+    ObjFile = cantFail(ObjectFile::createObjectFile(Source));
+  }
+
+  void initializeBOLT() {
+    Relocation::Arch = ObjFile->makeTriple().getArch();
+    BC = cantFail(BinaryContext::createBinaryContext(
+        ObjFile->makeTriple(), std::make_shared<orc::SymbolStringPool>(),
+        ObjFile->getFileName(), nullptr, /*IsPIC*/ false,
+        DWARFContext::create(*ObjFile.get()), {llvm::outs(), llvm::errs()}));
+    ASSERT_FALSE(!BC);
+  }
+
+  char ElfBuf[sizeof(typename ELF64LE::Ehdr)] = {};
+  std::unique_ptr<ObjectFile> ObjFile;
+  std::unique_ptr<BinaryContext> BC;
+
+  /// Compare LBREntries
+  bool checkLBREntry(const LBREntry &Lhs, const LBREntry &Rhs) {
+    return Lhs.From == Rhs.From && Lhs.To == Rhs.To &&
+           Lhs.Mispred == Rhs.Mispred;
+  }
+
+  /// Parse and check SPE brstack as LBR
+  void parseAndCheckBrstackEvents(
+      uint64_t PID,
+      const std::vector<SmallVector<LBREntry, 2>> &ExpectedSamples) {
+    int NumSamples = 0;
+
+    DataAggregator DA("<pseudo input>");
+    DA.ParsingBuf = opts::ReadPerfEvents;
+    DA.BC = BC.get();
+    DataAggregator::MMapInfo MMap;
+    DA.BinaryMMapInfo.insert(std::make_pair(PID, MMap));
+
+    // Process buffer.
+    while (DA.hasData()) {
+      ErrorOr<DataAggregator::PerfBranchSample> SampleRes =
+          DA.parseBranchSample();
+      if (std::error_code EC = SampleRes.getError())
+        EXPECT_NE(EC, std::errc::no_such_process);
+
+      DataAggregator::PerfBranchSample &Sample = SampleRes.get();
+      EXPECT_EQ(Sample.LBR.size(), ExpectedSamples[NumSamples].size());
+
+      // Check the parsed LBREntries.
+      const auto *ActualIter = Sample.LBR.begin();
+      const auto *ExpectIter = ExpectedSamples[NumSamples].begin();
+      while (ActualIter != Sample.LBR.end() &&
+             ExpectIter != ExpectedSamples[NumSamples].end())
----------------
paschalis-mpeis wrote:

nit/tip: may be able to use [zip_equal](https://llvm.org/docs/ProgrammersManual.html#the-zip-functions) with structured binding here.

https://github.com/llvm/llvm-project/pull/129231