1 files changed, 69 insertions, 0 deletions
diff --git a/third_party/llvm-project/DWARFDebugInfoEntry.cpp b/third_party/llvm-project/DWARFDebugInfoEntry.cpp
new file mode 100644
index 000000000..87eab34d5
--- /dev/null
+++ b/third_party/llvm-project/DWARFDebugInfoEntry.cpp
@@ -0,0 +1,69 @@
+//===- DWARFDebugInfoEntry.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
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
+#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
+#include "llvm/Support/DataExtractor.h"
+#include <cstddef>
+#include <cstdint>
+
+using namespace llvm;
+using namespace dwarf;
+
+bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U,
+                                             uint64_t *OffsetPtr) {
+  DWARFDataExtractor DebugInfoData = U.getDebugInfoExtractor();
+  const uint64_t UEndOffset = U.getNextUnitOffset();
+  return extractFast(U, OffsetPtr, DebugInfoData, UEndOffset, 0);
+}
+
+bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, uint64_t *OffsetPtr,
+                                      const DWARFDataExtractor &DebugInfoData,
+                                      uint64_t UEndOffset, uint32_t D) {
+  Offset = *OffsetPtr;
+  Depth = D;
+  if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
+    return false;
+  uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
+  if (0 == AbbrCode) {
+    // NULL debug tag entry.
+    AbbrevDecl = nullptr;
+    return true;
+  }
+  AbbrevDecl = U.getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
+  if (nullptr == AbbrevDecl) {
+    // Restore the original offset.
+    *OffsetPtr = Offset;
+    return false;
+  }
+  // See if all attributes in this DIE have fixed byte sizes. If so, we can
+  // just add this size to the offset to skip to the next DIE.
+  if (Optional<size_t> FixedSize = AbbrevDecl->getFixedAttributesByteSize(U)) {
+    *OffsetPtr += *FixedSize;
+    return true;
+  }
+
+  // Skip all data in the .debug_info for the attributes
+  for (const auto &AttrSpec : AbbrevDecl->attributes()) {
+    // Check if this attribute has a fixed byte size.
+    if (auto FixedSize = AttrSpec.getByteSize(U)) {
+      // Attribute byte size if fixed, just add the size to the offset.
+      *OffsetPtr += *FixedSize;
+    } else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData,
+                                          OffsetPtr, U.getFormParams())) {
+      // We failed to skip this attribute's value, restore the original offset
+      // and return the failure status.
+      *OffsetPtr = Offset;
+      return false;
+    }
+  }
+  return true;
+}