1 files changed, 198 insertions, 0 deletions
diff --git a/contrib/llvm/lib/XRay/InstrumentationMap.cpp b/contrib/llvm/lib/XRay/InstrumentationMap.cpp
new file mode 100644
index 0000000..d9ce255
--- /dev/null
+++ b/contrib/llvm/lib/XRay/InstrumentationMap.cpp
@@ -0,0 +1,198 @@
+//===- InstrumentationMap.cpp - XRay Instrumentation Map ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implementation of the InstrumentationMap type for XRay sleds.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/XRay/InstrumentationMap.h"
+#include "llvm/ADT/None.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Object/Binary.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/YAMLTraits.h"
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <system_error>
+#include <vector>
+
+using namespace llvm;
+using namespace xray;
+
+Optional<int32_t> InstrumentationMap::getFunctionId(uint64_t Addr) const {
+  auto I = FunctionIds.find(Addr);
+  if (I != FunctionIds.end())
+    return I->second;
+  return None;
+}
+
+Optional<uint64_t> InstrumentationMap::getFunctionAddr(int32_t FuncId) const {
+  auto I = FunctionAddresses.find(FuncId);
+  if (I != FunctionAddresses.end())
+    return I->second;
+  return None;
+}
+
+static Error
+loadELF64(StringRef Filename, object::OwningBinary<object::ObjectFile> &ObjFile,
+          InstrumentationMap::SledContainer &Sleds,
+          InstrumentationMap::FunctionAddressMap &FunctionAddresses,
+          InstrumentationMap::FunctionAddressReverseMap &FunctionIds) {
+  InstrumentationMap Map;
+
+  // Find the section named "xray_instr_map".
+  if (!ObjFile.getBinary()->isELF() ||
+      !(ObjFile.getBinary()->getArch() == Triple::x86_64 ||
+        ObjFile.getBinary()->getArch() == Triple::ppc64le))
+    return make_error<StringError>(
+        "File format not supported (only does ELF little endian 64-bit).",
+        std::make_error_code(std::errc::not_supported));
+
+  StringRef Contents = "";
+  const auto &Sections = ObjFile.getBinary()->sections();
+  auto I = llvm::find_if(Sections, [&](object::SectionRef Section) {
+    StringRef Name = "";
+    if (Section.getName(Name))
+      return false;
+    return Name == "xray_instr_map";
+  });
+
+  if (I == Sections.end())
+    return make_error<StringError>(
+        "Failed to find XRay instrumentation map.",
+        std::make_error_code(std::errc::executable_format_error));
+
+  if (I->getContents(Contents))
+    return errorCodeToError(
+        std::make_error_code(std::errc::executable_format_error));
+
+  // Copy the instrumentation map data into the Sleds data structure.
+  auto C = Contents.bytes_begin();
+  static constexpr size_t ELF64SledEntrySize = 32;
+
+  if ((C - Contents.bytes_end()) % ELF64SledEntrySize != 0)
+    return make_error<StringError>(
+        Twine("Instrumentation map entries not evenly divisible by size of "
+              "an XRay sled entry in ELF64."),
+        std::make_error_code(std::errc::executable_format_error));
+
+  int32_t FuncId = 1;
+  uint64_t CurFn = 0;
+  for (; C != Contents.bytes_end(); C += ELF64SledEntrySize) {
+    DataExtractor Extractor(
+        StringRef(reinterpret_cast<const char *>(C), ELF64SledEntrySize), true,
+        8);
+    Sleds.push_back({});
+    auto &Entry = Sleds.back();
+    uint32_t OffsetPtr = 0;
+    Entry.Address = Extractor.getU64(&OffsetPtr);
+    Entry.Function = Extractor.getU64(&OffsetPtr);
+    auto Kind = Extractor.getU8(&OffsetPtr);
+    static constexpr SledEntry::FunctionKinds Kinds[] = {
+        SledEntry::FunctionKinds::ENTRY, SledEntry::FunctionKinds::EXIT,
+        SledEntry::FunctionKinds::TAIL,
+    };
+    if (Kind >= sizeof(Kinds))
+      return errorCodeToError(
+          std::make_error_code(std::errc::executable_format_error));
+    Entry.Kind = Kinds[Kind];
+    Entry.AlwaysInstrument = Extractor.getU8(&OffsetPtr) != 0;
+
+    // We do replicate the function id generation scheme implemented in the
+    // XRay runtime.
+    // FIXME: Figure out how to keep this consistent with the XRay runtime.
+    if (CurFn == 0) {
+      CurFn = Entry.Function;
+      FunctionAddresses[FuncId] = Entry.Function;
+      FunctionIds[Entry.Function] = FuncId;
+    }
+    if (Entry.Function != CurFn) {
+      ++FuncId;
+      CurFn = Entry.Function;
+      FunctionAddresses[FuncId] = Entry.Function;
+      FunctionIds[Entry.Function] = FuncId;
+    }
+  }
+  return Error::success();
+}
+
+static Error
+loadYAML(int Fd, size_t FileSize, StringRef Filename,
+         InstrumentationMap::SledContainer &Sleds,
+         InstrumentationMap::FunctionAddressMap &FunctionAddresses,
+         InstrumentationMap::FunctionAddressReverseMap &FunctionIds) {
+  std::error_code EC;
+  sys::fs::mapped_file_region MappedFile(
+      Fd, sys::fs::mapped_file_region::mapmode::readonly, FileSize, 0, EC);
+  if (EC)
+    return make_error<StringError>(
+        Twine("Failed memory-mapping file '") + Filename + "'.", EC);
+
+  std::vector<YAMLXRaySledEntry> YAMLSleds;
+  yaml::Input In(StringRef(MappedFile.data(), MappedFile.size()));
+  In >> YAMLSleds;
+  if (In.error())
+    return make_error<StringError>(
+        Twine("Failed loading YAML document from '") + Filename + "'.",
+        In.error());
+
+  Sleds.reserve(YAMLSleds.size());
+  for (const auto &Y : YAMLSleds) {
+    FunctionAddresses[Y.FuncId] = Y.Function;
+    FunctionIds[Y.Function] = Y.FuncId;
+    Sleds.push_back(
+        SledEntry{Y.Address, Y.Function, Y.Kind, Y.AlwaysInstrument});
+  }
+  return Error::success();
+}
+
+// FIXME: Create error types that encapsulate a bit more information than what
+// StringError instances contain.
+Expected<InstrumentationMap>
+llvm::xray::loadInstrumentationMap(StringRef Filename) {
+  // At this point we assume the file is an object file -- and if that doesn't
+  // work, we treat it as YAML.
+  // FIXME: Extend to support non-ELF and non-x86_64 binaries.
+
+  InstrumentationMap Map;
+  auto ObjectFileOrError = object::ObjectFile::createObjectFile(Filename);
+  if (!ObjectFileOrError) {
+    auto E = ObjectFileOrError.takeError();
+    // We try to load it as YAML if the ELF load didn't work.
+    int Fd;
+    if (sys::fs::openFileForRead(Filename, Fd))
+      return std::move(E);
+
+    uint64_t FileSize;
+    if (sys::fs::file_size(Filename, FileSize))
+      return std::move(E);
+
+    // If the file is empty, we return the original error.
+    if (FileSize == 0)
+      return std::move(E);
+
+    // From this point on the errors will be only for the YAML parts, so we
+    // consume the errors at this point.
+    consumeError(std::move(E));
+    if (auto E = loadYAML(Fd, FileSize, Filename, Map.Sleds,
+                          Map.FunctionAddresses, Map.FunctionIds))
+      return std::move(E);
+  } else if (auto E = loadELF64(Filename, *ObjectFileOrError, Map.Sleds,
+                                Map.FunctionAddresses, Map.FunctionIds)) {
+    return std::move(E);
+  }
+  return Map;
+}