1 files changed, 45 insertions, 8 deletions
diff --git a/llvm/lib/DebugInfo/GSYM/MergedFunctionsInfo.cpp b/llvm/lib/DebugInfo/GSYM/MergedFunctionsInfo.cpp
index 4efae22..d2c28f3 100644
--- a/llvm/lib/DebugInfo/GSYM/MergedFunctionsInfo.cpp
+++ b/llvm/lib/DebugInfo/GSYM/MergedFunctionsInfo.cpp
@@ -35,22 +35,59 @@ llvm::Error MergedFunctionsInfo::encode(FileWriter &Out) const {
 llvm::Expected<MergedFunctionsInfo>
 MergedFunctionsInfo::decode(DataExtractor &Data, uint64_t BaseAddr) {
   MergedFunctionsInfo MFI;
+  auto FuncExtractorsOrError = MFI.getFuncsDataExtractors(Data);
+
+  if (!FuncExtractorsOrError)
+    return FuncExtractorsOrError.takeError();
+
+  for (DataExtractor &FuncData : *FuncExtractorsOrError) {
+    llvm::Expected<FunctionInfo> FI = FunctionInfo::decode(FuncData, BaseAddr);
+    if (!FI)
+      return FI.takeError();
+    MFI.MergedFunctions.push_back(std::move(*FI));
+  }
+
+  return MFI;
+}
+
+llvm::Expected<std::vector<DataExtractor>>
+MergedFunctionsInfo::getFuncsDataExtractors(DataExtractor &Data) {
+  std::vector<DataExtractor> Results;
   uint64_t Offset = 0;
+
+  // Ensure there is enough data to read the function count.
+  if (!Data.isValidOffsetForDataOfSize(Offset, 4))
+    return createStringError(
+        std::errc::io_error,
+        "unable to read the function count at offset 0x%8.8" PRIx64, Offset);
+
   uint32_t Count = Data.getU32(&Offset);
 
   for (uint32_t i = 0; i < Count; ++i) {
+    // Ensure there is enough data to read the function size.
+    if (!Data.isValidOffsetForDataOfSize(Offset, 4))
+      return createStringError(
+          std::errc::io_error,
+          "unable to read size of function %u at offset 0x%8.8" PRIx64, i,
+          Offset);
+
     uint32_t FnSize = Data.getU32(&Offset);
-    DataExtractor FnData(Data.getData().substr(Offset, FnSize),
+
+    // Ensure there is enough data for the function content.
+    if (!Data.isValidOffsetForDataOfSize(Offset, FnSize))
+      return createStringError(
+          std::errc::io_error,
+          "function data is truncated for function %u at offset 0x%8.8" PRIx64
+          ", expected size %u",
+          i, Offset, FnSize);
+
+    // Extract the function data.
+    Results.emplace_back(Data.getData().substr(Offset, FnSize),
                          Data.isLittleEndian(), Data.getAddressSize());
-    llvm::Expected<FunctionInfo> FI =
-        FunctionInfo::decode(FnData, BaseAddr + Offset);
-    if (!FI)
-      return FI.takeError();
-    MFI.MergedFunctions.push_back(std::move(*FI));
+
     Offset += FnSize;
   }
-
-  return MFI;
+  return Results;
 }
 
 bool operator==(const MergedFunctionsInfo &LHS,