1 files changed, 57 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/BinaryFormat/COFF.cpp b/contrib/llvm-project/llvm/lib/BinaryFormat/COFF.cpp
new file mode 100644
index 000000000000..8fbee0218b79
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/BinaryFormat/COFF.cpp
@@ -0,0 +1,57 @@
+//===- llvm/BinaryFormat/COFF.cpp - The COFF format -----------------------===//
+//
+// 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/BinaryFormat/COFF.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Twine.h"
+
+// Maximum offsets for different string table entry encodings.
+enum : unsigned { Max7DecimalOffset = 9999999U };
+enum : uint64_t { MaxBase64Offset = 0xFFFFFFFFFULL }; // 64^6, including 0
+
+// Encode a string table entry offset in base 64, padded to 6 chars, and
+// prefixed with a double slash: '//AAAAAA', '//AAAAAB', ...
+// Buffer must be at least 8 bytes large. No terminating null appended.
+static void encodeBase64StringEntry(char *Buffer, uint64_t Value) {
+  assert(Value > Max7DecimalOffset && Value <= MaxBase64Offset &&
+         "Illegal section name encoding for value");
+
+  static const char Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                                 "abcdefghijklmnopqrstuvwxyz"
+                                 "0123456789+/";
+
+  Buffer[0] = '/';
+  Buffer[1] = '/';
+
+  char *Ptr = Buffer + 7;
+  for (unsigned i = 0; i < 6; ++i) {
+    unsigned Rem = Value % 64;
+    Value /= 64;
+    *(Ptr--) = Alphabet[Rem];
+  }
+}
+
+bool llvm::COFF::encodeSectionName(char *Out, uint64_t Offset) {
+  if (Offset <= Max7DecimalOffset) {
+    // Offsets of 7 digits or less are encoded in ASCII.
+    SmallVector<char, COFF::NameSize> Buffer;
+    Twine('/').concat(Twine(Offset)).toVector(Buffer);
+    assert(Buffer.size() <= COFF::NameSize && Buffer.size() >= 2);
+    std::memcpy(Out, Buffer.data(), Buffer.size());
+    return true;
+  }
+
+  if (Offset <= MaxBase64Offset) {
+    // Starting with 10,000,000, offsets are encoded as base64.
+    encodeBase64StringEntry(Out, Offset);
+    return true;
+  }
+
+  // The offset is too large to be encoded.
+  return false;
+}