[lld] [llvm] [Hexagon] Add support for decoding PLT symbols (PR #123425)

[via llvm-commits]

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@@ -734,8 +734,42 @@ class HexagonMCInstrAnalysis : public MCInstrAnalysis {
     Target = Value;
     return true;
   }
+
+  uint32_t getValueFromMask(uint32_t Instruction, uint32_t Mask) const {
+    uint32_t Result = 0;
+    uint32_t Offset = 0;
+    while (Mask) {
+      if (Instruction & (Mask & -Mask))
+        Result |= (1 << Offset);
+      Mask &= (Mask - 1);
+      ++Offset;
+    }
+    return Result;
+  }
+
+  std::vector<std::pair<uint64_t, uint64_t>>
+  findPltEntries(uint64_t PltSectionVA, ArrayRef<uint8_t> PltContents,
+                 const Triple &TargetTriple) const override {
+    // Do a lightweight parsing of PLT entries.
+    std::vector<std::pair<uint64_t, uint64_t>> Result;
+    for (uint64_t Byte = 0x0, End = PltContents.size(); Byte < End; Byte += 4) {
+      // Recognize immext(##gotpltn)
+      uint32_t ImmExt = support::endian::read32le(PltContents.data() + Byte);
+      if ((ImmExt & 0x00004000) != 0x00004000)
+        continue;
+      uint32_t LoadGotPlt =
+          support::endian::read32le(PltContents.data() + Byte + 4);
+      if ((LoadGotPlt & 0x6a49c00c) != 0x6a49c00c)
+        continue;
+      uint32_t Address = (getValueFromMask(ImmExt, 0xfff3fff) << 6) +
+                         getValueFromMask(LoadGotPlt, 0x1f80) + PltSectionVA +
+                         Byte;
+      Result.push_back(std::make_pair(PltSectionVA + Byte, Address));
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quic-areg wrote:

Done

https://github.com/llvm/llvm-project/pull/123425