1 files changed, 30 insertions, 1 deletions
diff --git a/llvm/include/llvm/DebugInfo/GSYM/FunctionInfo.h b/llvm/include/llvm/DebugInfo/GSYM/FunctionInfo.h
index 63e18bb2ecd5..893cfc1eb07c 100644
--- a/llvm/include/llvm/DebugInfo/GSYM/FunctionInfo.h
+++ b/llvm/include/llvm/DebugInfo/GSYM/FunctionInfo.h
@@ -12,6 +12,7 @@
 #include "llvm/ADT/Optional.h"
 #include "llvm/DebugInfo/GSYM/InlineInfo.h"
 #include "llvm/DebugInfo/GSYM/LineTable.h"
+#include "llvm/DebugInfo/GSYM/LookupResult.h"
 #include "llvm/DebugInfo/GSYM/Range.h"
 #include "llvm/DebugInfo/GSYM/StringTable.h"
 #include <tuple>
@@ -21,6 +22,7 @@ namespace llvm {
 class raw_ostream;
 namespace gsym {
 
+class GsymReader;
 /// Function information in GSYM files encodes information for one contiguous
 /// address range. If a function has discontiguous address ranges, they will
 /// need to be encoded using multiple FunctionInfo objects.
@@ -30,7 +32,7 @@ namespace gsym {
 /// The function information gets the function start address as an argument
 /// to the FunctionInfo::decode(...) function. This information is calculated
 /// from the GSYM header and an address offset from the GSYM address offsets
-/// table. The encoded FunctionInfo information must be alinged to a 4 byte
+/// table. The encoded FunctionInfo information must be aligned to a 4 byte
 /// boundary.
 ///
 /// The encoded data for a FunctionInfo starts with fixed data that all
@@ -140,6 +142,33 @@ struct FunctionInfo {
   /// function info that was successfully written into the stream.
   llvm::Expected<uint64_t> encode(FileWriter &O) const;
 
+
+  /// Lookup an address within a FunctionInfo object's data stream.
+  ///
+  /// Instead of decoding an entire FunctionInfo object when doing lookups,
+  /// we can decode only the information we need from the FunctionInfo's data
+  /// for the specific address. The lookup result information is returned as
+  /// a LookupResult.
+  ///
+  /// \param Data The binary stream to read the data from. This object must
+  /// have the data for the object starting at offset zero. The data
+  /// can contain more data than needed.
+  ///
+  /// \param GR The GSYM reader that contains the string and file table that
+  /// will be used to fill in information in the returned result.
+  ///
+  /// \param FuncAddr The function start address decoded from the GsymReader.
+  ///
+  /// \param Addr The address to lookup.
+  ///
+  /// \returns An LookupResult or an error describing the issue that was
+  /// encountered during decoding. An error should only be returned if the
+  /// address is not contained in the FunctionInfo or if the data is corrupted.
+  static llvm::Expected<LookupResult> lookup(DataExtractor &Data,
+                                             const GsymReader &GR,
+                                             uint64_t FuncAddr,
+                                             uint64_t Addr);
+
   uint64_t startAddress() const { return Range.Start; }
   uint64_t endAddress() const { return Range.End; }
   uint64_t size() const { return Range.size(); }