1 files changed, 303 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/ExecutionEngine/Orc/Debugging/PerfSupportPlugin.cpp b/contrib/llvm-project/llvm/lib/ExecutionEngine/Orc/Debugging/PerfSupportPlugin.cpp
new file mode 100644
index 000000000000..fffecfc97814
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/ExecutionEngine/Orc/Debugging/PerfSupportPlugin.cpp
@@ -0,0 +1,303 @@
+//===----- PerfSupportPlugin.cpp --- Utils for perf support -----*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Handles support for registering code with perf
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ExecutionEngine/Orc/Debugging/PerfSupportPlugin.h"
+
+#include "llvm/ExecutionEngine/JITLink/x86_64.h"
+#include "llvm/ExecutionEngine/Orc/Debugging/DebugInfoSupport.h"
+#include "llvm/ExecutionEngine/Orc/LookupAndRecordAddrs.h"
+#include "llvm/ExecutionEngine/Orc/Shared/WrapperFunctionUtils.h"
+
+#define DEBUG_TYPE "orc"
+
+using namespace llvm;
+using namespace llvm::orc;
+using namespace llvm::jitlink;
+
+namespace {
+
+// Creates an EH frame header prepared for a 32-bit relative relocation
+// to the start of the .eh_frame section. Absolute injects a 64-bit absolute
+// address space offset 4 bytes from the start instead of 4 bytes
+Expected<std::string> createX64EHFrameHeader(Section &EHFrame,
+                                             llvm::endianness endianness,
+                                             bool absolute) {
+  uint8_t Version = 1;
+  uint8_t EhFramePtrEnc = 0;
+  if (absolute) {
+    EhFramePtrEnc |= dwarf::DW_EH_PE_sdata8 | dwarf::DW_EH_PE_absptr;
+  } else {
+    EhFramePtrEnc |= dwarf::DW_EH_PE_sdata4 | dwarf::DW_EH_PE_datarel;
+  }
+  uint8_t FDECountEnc = dwarf::DW_EH_PE_omit;
+  uint8_t TableEnc = dwarf::DW_EH_PE_omit;
+  // X86_64_64 relocation to the start of the .eh_frame section
+  uint32_t EHFrameRelocation = 0;
+  // uint32_t FDECount = 0;
+  // Skip the FDE binary search table
+  // We'd have to reprocess the CIEs to get this information,
+  // which seems like more trouble than it's worth
+  // TODO consider implementing this.
+  // binary search table goes here
+
+  size_t HeaderSize =
+      (sizeof(Version) + sizeof(EhFramePtrEnc) + sizeof(FDECountEnc) +
+       sizeof(TableEnc) +
+       (absolute ? sizeof(uint64_t) : sizeof(EHFrameRelocation)));
+  std::string HeaderContent(HeaderSize, '\0');
+  BinaryStreamWriter Writer(
+      MutableArrayRef<uint8_t>(
+          reinterpret_cast<uint8_t *>(HeaderContent.data()), HeaderSize),
+      endianness);
+  if (auto Err = Writer.writeInteger(Version))
+    return std::move(Err);
+  if (auto Err = Writer.writeInteger(EhFramePtrEnc))
+    return std::move(Err);
+  if (auto Err = Writer.writeInteger(FDECountEnc))
+    return std::move(Err);
+  if (auto Err = Writer.writeInteger(TableEnc))
+    return std::move(Err);
+  if (absolute) {
+    uint64_t EHFrameAddr = SectionRange(EHFrame).getStart().getValue();
+    if (auto Err = Writer.writeInteger(EHFrameAddr))
+      return std::move(Err);
+  } else {
+    if (auto Err = Writer.writeInteger(EHFrameRelocation))
+      return std::move(Err);
+  }
+  return HeaderContent;
+}
+
+constexpr StringRef RegisterPerfStartSymbolName =
+    "llvm_orc_registerJITLoaderPerfStart";
+constexpr StringRef RegisterPerfEndSymbolName =
+    "llvm_orc_registerJITLoaderPerfEnd";
+constexpr StringRef RegisterPerfImplSymbolName =
+    "llvm_orc_registerJITLoaderPerfImpl";
+
+static PerfJITCodeLoadRecord
+getCodeLoadRecord(const Symbol &Sym, std::atomic<uint64_t> &CodeIndex) {
+  PerfJITCodeLoadRecord Record;
+  auto Name = Sym.getName();
+  auto Addr = Sym.getAddress();
+  auto Size = Sym.getSize();
+  Record.Prefix.Id = PerfJITRecordType::JIT_CODE_LOAD;
+  // Runtime sets PID
+  Record.Pid = 0;
+  // Runtime sets TID
+  Record.Tid = 0;
+  Record.Vma = Addr.getValue();
+  Record.CodeAddr = Addr.getValue();
+  Record.CodeSize = Size;
+  Record.CodeIndex = CodeIndex++;
+  Record.Name = Name.str();
+  // Initialize last, once all the other fields are filled
+  Record.Prefix.TotalSize =
+      (2 * sizeof(uint32_t)   // id, total_size
+       + sizeof(uint64_t)     // timestamp
+       + 2 * sizeof(uint32_t) // pid, tid
+       + 4 * sizeof(uint64_t) // vma, code_addr, code_size, code_index
+       + Name.size() + 1      // symbol name
+       + Record.CodeSize      // code
+      );
+  return Record;
+}
+
+static std::optional<PerfJITDebugInfoRecord>
+getDebugInfoRecord(const Symbol &Sym, DWARFContext &DC) {
+  auto &Section = Sym.getBlock().getSection();
+  auto Addr = Sym.getAddress();
+  auto Size = Sym.getSize();
+  auto SAddr = object::SectionedAddress{Addr.getValue(), Section.getOrdinal()};
+  LLVM_DEBUG(dbgs() << "Getting debug info for symbol " << Sym.getName()
+                    << " at address " << Addr.getValue() << " with size "
+                    << Size << "\n"
+                    << "Section ordinal: " << Section.getOrdinal() << "\n");
+  auto LInfo = DC.getLineInfoForAddressRange(
+      SAddr, Size, DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath);
+  if (LInfo.empty()) {
+    // No line info available
+    LLVM_DEBUG(dbgs() << "No line info available\n");
+    return std::nullopt;
+  }
+  PerfJITDebugInfoRecord Record;
+  Record.Prefix.Id = PerfJITRecordType::JIT_CODE_DEBUG_INFO;
+  Record.CodeAddr = Addr.getValue();
+  for (const auto &Entry : LInfo) {
+    auto Addr = Entry.first;
+    // The function re-created by perf is preceded by a elf
+    // header. Need to adjust for that, otherwise the results are
+    // wrong.
+    Addr += 0x40;
+    Record.Entries.push_back({Addr, Entry.second.Line,
+                              Entry.second.Discriminator,
+                              Entry.second.FileName});
+  }
+  size_t EntriesBytes = (2   // record header
+                         + 2 // record fields
+                         ) *
+                        sizeof(uint64_t);
+  for (const auto &Entry : Record.Entries) {
+    EntriesBytes +=
+        sizeof(uint64_t) + 2 * sizeof(uint32_t); // Addr, Line/Discrim
+    EntriesBytes += Entry.Name.size() + 1;       // Name
+  }
+  Record.Prefix.TotalSize = EntriesBytes;
+  LLVM_DEBUG(dbgs() << "Created debug info record\n"
+                    << "Total size: " << Record.Prefix.TotalSize << "\n"
+                    << "Nr entries: " << Record.Entries.size() << "\n");
+  return Record;
+}
+
+static Expected<PerfJITCodeUnwindingInfoRecord>
+getUnwindingRecord(LinkGraph &G) {
+  PerfJITCodeUnwindingInfoRecord Record;
+  Record.Prefix.Id = PerfJITRecordType::JIT_CODE_UNWINDING_INFO;
+  Record.Prefix.TotalSize = 0;
+  auto Eh_frame = G.findSectionByName(".eh_frame");
+  if (!Eh_frame) {
+    LLVM_DEBUG(dbgs() << "No .eh_frame section found\n");
+    return Record;
+  }
+  if (!G.getTargetTriple().isOSBinFormatELF()) {
+    LLVM_DEBUG(dbgs() << "Not an ELF file, will not emit unwinding info\n");
+    return Record;
+  }
+  auto SR = SectionRange(*Eh_frame);
+  auto EHFrameSize = SR.getSize();
+  auto Eh_frame_hdr = G.findSectionByName(".eh_frame_hdr");
+  if (!Eh_frame_hdr) {
+    if (G.getTargetTriple().getArch() == Triple::x86_64) {
+      auto Hdr = createX64EHFrameHeader(*Eh_frame, G.getEndianness(), true);
+      if (!Hdr)
+        return Hdr.takeError();
+      Record.EHFrameHdr = std::move(*Hdr);
+    } else {
+      LLVM_DEBUG(dbgs() << "No .eh_frame_hdr section found\n");
+      return Record;
+    }
+    Record.EHFrameHdrAddr = 0;
+    Record.EHFrameHdrSize = Record.EHFrameHdr.size();
+    Record.UnwindDataSize = EHFrameSize + Record.EHFrameHdrSize;
+    Record.MappedSize = 0; // Because the EHFrame header was not mapped
+  } else {
+    auto SR = SectionRange(*Eh_frame_hdr);
+    Record.EHFrameHdrAddr = SR.getStart().getValue();
+    Record.EHFrameHdrSize = SR.getSize();
+    Record.UnwindDataSize = EHFrameSize + Record.EHFrameHdrSize;
+    Record.MappedSize = Record.UnwindDataSize;
+  }
+  Record.EHFrameAddr = SR.getStart().getValue();
+  Record.Prefix.TotalSize =
+      (2 * sizeof(uint32_t) // id, total_size
+       + sizeof(uint64_t)   // timestamp
+       +
+       3 * sizeof(uint64_t) // unwind_data_size, eh_frame_hdr_size, mapped_size
+       + Record.UnwindDataSize // eh_frame_hdr, eh_frame
+      );
+  LLVM_DEBUG(dbgs() << "Created unwind record\n"
+                    << "Total size: " << Record.Prefix.TotalSize << "\n"
+                    << "Unwind size: " << Record.UnwindDataSize << "\n"
+                    << "EHFrame size: " << EHFrameSize << "\n"
+                    << "EHFrameHdr size: " << Record.EHFrameHdrSize << "\n");
+  return Record;
+}
+
+static PerfJITRecordBatch getRecords(ExecutionSession &ES, LinkGraph &G,
+                                     std::atomic<uint64_t> &CodeIndex,
+                                     bool EmitDebugInfo, bool EmitUnwindInfo) {
+  std::unique_ptr<DWARFContext> DC;
+  StringMap<std::unique_ptr<MemoryBuffer>> DCBacking;
+  if (EmitDebugInfo) {
+    auto EDC = createDWARFContext(G);
+    if (!EDC) {
+      ES.reportError(EDC.takeError());
+      EmitDebugInfo = false;
+    } else {
+      DC = std::move(EDC->first);
+      DCBacking = std::move(EDC->second);
+    }
+  }
+  PerfJITRecordBatch Batch;
+  for (auto Sym : G.defined_symbols()) {
+    if (!Sym->hasName() || !Sym->isCallable())
+      continue;
+    if (EmitDebugInfo) {
+      auto DebugInfo = getDebugInfoRecord(*Sym, *DC);
+      if (DebugInfo)
+        Batch.DebugInfoRecords.push_back(std::move(*DebugInfo));
+    }
+    Batch.CodeLoadRecords.push_back(getCodeLoadRecord(*Sym, CodeIndex));
+  }
+  if (EmitUnwindInfo) {
+    auto UWR = getUnwindingRecord(G);
+    if (!UWR) {
+      ES.reportError(UWR.takeError());
+    } else {
+      Batch.UnwindingRecord = std::move(*UWR);
+    }
+  } else {
+    Batch.UnwindingRecord.Prefix.TotalSize = 0;
+  }
+  return Batch;
+}
+} // namespace
+
+PerfSupportPlugin::PerfSupportPlugin(ExecutorProcessControl &EPC,
+                                     ExecutorAddr RegisterPerfStartAddr,
+                                     ExecutorAddr RegisterPerfEndAddr,
+                                     ExecutorAddr RegisterPerfImplAddr,
+                                     bool EmitDebugInfo, bool EmitUnwindInfo)
+    : EPC(EPC), RegisterPerfStartAddr(RegisterPerfStartAddr),
+      RegisterPerfEndAddr(RegisterPerfEndAddr),
+      RegisterPerfImplAddr(RegisterPerfImplAddr), CodeIndex(0),
+      EmitDebugInfo(EmitDebugInfo), EmitUnwindInfo(EmitUnwindInfo) {
+  cantFail(EPC.callSPSWrapper<void()>(RegisterPerfStartAddr));
+}
+PerfSupportPlugin::~PerfSupportPlugin() {
+  cantFail(EPC.callSPSWrapper<void()>(RegisterPerfEndAddr));
+}
+
+void PerfSupportPlugin::modifyPassConfig(MaterializationResponsibility &MR,
+                                         LinkGraph &G,
+                                         PassConfiguration &Config) {
+  Config.PostFixupPasses.push_back([this](LinkGraph &G) {
+    auto Batch = getRecords(EPC.getExecutionSession(), G, CodeIndex,
+                            EmitDebugInfo, EmitUnwindInfo);
+    G.allocActions().push_back(
+        {cantFail(shared::WrapperFunctionCall::Create<
+                  shared::SPSArgList<shared::SPSPerfJITRecordBatch>>(
+             RegisterPerfImplAddr, Batch)),
+         {}});
+    return Error::success();
+  });
+}
+
+Expected<std::unique_ptr<PerfSupportPlugin>>
+PerfSupportPlugin::Create(ExecutorProcessControl &EPC, JITDylib &JD,
+                          bool EmitDebugInfo, bool EmitUnwindInfo) {
+  if (!EPC.getTargetTriple().isOSBinFormatELF()) {
+    return make_error<StringError>(
+        "Perf support only available for ELF LinkGraphs!",
+        inconvertibleErrorCode());
+  }
+  auto &ES = EPC.getExecutionSession();
+  ExecutorAddr StartAddr, EndAddr, ImplAddr;
+  if (auto Err = lookupAndRecordAddrs(
+          ES, LookupKind::Static, makeJITDylibSearchOrder({&JD}),
+          {{ES.intern(RegisterPerfStartSymbolName), &StartAddr},
+           {ES.intern(RegisterPerfEndSymbolName), &EndAddr},
+           {ES.intern(RegisterPerfImplSymbolName), &ImplAddr}}))
+    return std::move(Err);
+  return std::make_unique<PerfSupportPlugin>(EPC, StartAddr, EndAddr, ImplAddr,
+                                             EmitDebugInfo, EmitUnwindInfo);
+}