[llvm] [PDB] Add public symbol lookup by address (PR #157361)

[via llvm-commits]

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@@ -96,3 +99,91 @@ Error PublicsStream::reload() {
                                 "Corrupted publics stream.");
   return Error::success();
 }
+
+static uint32_t compareSegmentOffset(uint16_t LhsSegment, uint32_t LhsOffset,
+                                     uint16_t RhsSegment, uint32_t RhsOffset) {
+  if (LhsSegment == RhsSegment)
+    return LhsOffset - RhsOffset;
+  return LhsSegment - RhsSegment;
+}
+
+static uint32_t compareSegmentOffset(uint16_t LhsSegment, uint32_t LhsOffst,
+                                     const codeview::PublicSym32 &Rhs) {
+  return compareSegmentOffset(LhsSegment, LhsOffst, Rhs.Segment, Rhs.Offset);
+}
+
+// This is a reimplementation of NearestSym:
+// https://github.com/microsoft/microsoft-pdb/blob/805655a28bd8198004be2ac27e6e0290121a5e89/PDB/dbi/gsi.cpp#L1492-L1581
+std::optional<std::pair<codeview::PublicSym32, size_t>>
+PublicsStream::findByAddress(const SymbolStream &Symbols, uint16_t Segment,
+                             uint32_t Offset) const {
+  // The address map is sorted by address, so we do binary search.
+  // Each element is an offset into the symbols for a public symbol.
+  auto Lo = AddressMap.begin();
+  auto Hi = AddressMap.end();
+  Hi -= 1;
+
+  while (Lo < Hi) {
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Nerixyz wrote:

Yes, thank you!

https://github.com/llvm/llvm-project/pull/157361