1 files changed, 138 insertions, 0 deletions
diff --git a/third_party/llvm-project/DWARFDebugAbbrev.cpp b/third_party/llvm-project/DWARFDebugAbbrev.cpp
new file mode 100644
index 000000000..4afac2f99
--- /dev/null
+++ b/third_party/llvm-project/DWARFDebugAbbrev.cpp
@@ -0,0 +1,138 @@
+//===- DWARFDebugAbbrev.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/DWARFDebugAbbrev.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cinttypes>
+#include <cstdint>
+
+using namespace llvm;
+
+DWARFAbbreviationDeclarationSet::DWARFAbbreviationDeclarationSet() {
+  clear();
+}
+
+void DWARFAbbreviationDeclarationSet::clear() {
+  Offset = 0;
+  FirstAbbrCode = 0;
+  Decls.clear();
+}
+
+bool DWARFAbbreviationDeclarationSet::extract(DataExtractor Data,
+                                              uint64_t *OffsetPtr) {
+  clear();
+  const uint64_t BeginOffset = *OffsetPtr;
+  Offset = BeginOffset;
+  DWARFAbbreviationDeclaration AbbrDecl;
+  uint32_t PrevAbbrCode = 0;
+  while (AbbrDecl.extract(Data, OffsetPtr)) {
+    if (FirstAbbrCode == 0) {
+      FirstAbbrCode = AbbrDecl.getCode();
+    } else {
+      if (PrevAbbrCode + 1 != AbbrDecl.getCode()) {
+        // Codes are not consecutive, can't do O(1) lookups.
+        FirstAbbrCode = UINT32_MAX;
+      }
+    }
+    PrevAbbrCode = AbbrDecl.getCode();
+    Decls.push_back(std::move(AbbrDecl));
+  }
+  return BeginOffset != *OffsetPtr;
+}
+
+void DWARFAbbreviationDeclarationSet::dump(raw_ostream &OS) const {
+  for (const auto &Decl : Decls)
+    Decl.dump(OS);
+}
+
+const DWARFAbbreviationDeclaration *
+DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(
+    uint32_t AbbrCode) const {
+  if (FirstAbbrCode == UINT32_MAX) {
+    for (const auto &Decl : Decls) {
+      if (Decl.getCode() == AbbrCode)
+        return &Decl;
+    }
+    return nullptr;
+  }
+  if (AbbrCode < FirstAbbrCode || AbbrCode >= FirstAbbrCode + Decls.size())
+    return nullptr;
+  return &Decls[AbbrCode - FirstAbbrCode];
+}
+
+DWARFDebugAbbrev::DWARFDebugAbbrev() { clear(); }
+
+void DWARFDebugAbbrev::clear() {
+  AbbrDeclSets.clear();
+  PrevAbbrOffsetPos = AbbrDeclSets.end();
+}
+
+void DWARFDebugAbbrev::extract(DataExtractor Data) {
+  clear();
+  this->Data = Data;
+}
+
+void DWARFDebugAbbrev::parse() const {
+  if (!Data)
+    return;
+  uint64_t Offset = 0;
+  auto I = AbbrDeclSets.begin();
+  while (Data->isValidOffset(Offset)) {
+    while (I != AbbrDeclSets.end() && I->first < Offset)
+      ++I;
+    uint64_t CUAbbrOffset = Offset;
+    DWARFAbbreviationDeclarationSet AbbrDecls;
+    if (!AbbrDecls.extract(*Data, &Offset))
+      break;
+    AbbrDeclSets.insert(I, std::make_pair(CUAbbrOffset, std::move(AbbrDecls)));
+  }
+  Data = None;
+}
+
+void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
+  parse();
+
+  if (AbbrDeclSets.empty()) {
+    OS << "< EMPTY >\n";
+    return;
+  }
+
+  for (const auto &I : AbbrDeclSets) {
+    OS << format("Abbrev table for offset: 0x%8.8" PRIx64 "\n", I.first);
+    I.second.dump(OS);
+  }
+}
+
+const DWARFAbbreviationDeclarationSet*
+DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const {
+  const auto End = AbbrDeclSets.end();
+  if (PrevAbbrOffsetPos != End && PrevAbbrOffsetPos->first == CUAbbrOffset) {
+    return &(PrevAbbrOffsetPos->second);
+  }
+
+  const auto Pos = AbbrDeclSets.find(CUAbbrOffset);
+  if (Pos != End) {
+    PrevAbbrOffsetPos = Pos;
+    return &(Pos->second);
+  }
+
+  if (Data && CUAbbrOffset < Data->getData().size()) {
+    uint64_t Offset = CUAbbrOffset;
+    DWARFAbbreviationDeclarationSet AbbrDecls;
+    if (!AbbrDecls.extract(*Data, &Offset))
+      return nullptr;
+    PrevAbbrOffsetPos =
+        AbbrDeclSets.insert(std::make_pair(CUAbbrOffset, std::move(AbbrDecls)))
+            .first;
+    return &PrevAbbrOffsetPos->second;
+  }
+
+  return nullptr;
+}