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

[Paschalis Mpeis via llvm-commits]

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@@ -0,0 +1,119 @@
+//===- 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:
+  using Trace = DataAggregator::Trace;
+
+  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;
+
+  // Parse and check SPE brstack as LBR.
+  void parseAndCheckBrstackEvents(uint64_t PID, uint64_t From, uint64_t To,
+                                  uint64_t Count, size_t SampleSize) {
+    DataAggregator DA("<pseudo input>");
+    DA.ParsingBuf = opts::ReadPerfEvents;
+    DA.BC = BC.get();
+    DataAggregator::MMapInfo MMap;
+    DA.BinaryMMapInfo.insert(std::make_pair(PID, MMap));
+
+    DA.parseBranchEvents();
+
+    EXPECT_EQ(DA.BranchLBRs.size(), SampleSize);
----------------
paschalis-mpeis wrote:

Thanks for simplifying the tests! 🙂 

Recent changes in bolt profile structures have now enabled this [previous comment](https://github.com/llvm/llvm-project/pull/129231#discussion_r2037463440).

I think we can re-introduce the loop, checking on each entry the mispreds and the taken counts. Just like what is done here for a particular entry (`1234, 0xd001, 0xd002`), but instead do it in a loop, for all `ExpectedSamples`.

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