[llvm-xray] Store offset pointers in temporaries

DataExtractor::getU64 modifies the OffsetPtr which also pass to
RelocateOrElse which breaks on Windows. This addresses the issue
introduced in r349120.

Differential Revision: https://reviews.llvm.org/D55689

llvm-svn: 349129
diff --git a/llvm/lib/XRay/InstrumentationMap.cpp b/llvm/lib/XRay/InstrumentationMap.cpp
index d33fb4a..e90446c 100644
--- a/llvm/lib/XRay/InstrumentationMap.cpp
+++ b/llvm/lib/XRay/InstrumentationMap.cpp
@@ -137,8 +137,10 @@
     Sleds.push_back({});
     auto &Entry = Sleds.back();
     uint32_t OffsetPtr = 0;
-    Entry.Address = RelocateOrElse(OffsetPtr, Extractor.getU64(&OffsetPtr));
-    Entry.Function = RelocateOrElse(OffsetPtr, Extractor.getU64(&OffsetPtr));
+    uint32_t AddrPtr = OffsetPtr;
+    Entry.Address = RelocateOrElse(AddrOff, Extractor.getU64(&OffsetPtr));
+    uint32_t FuncPtr = OffsetPtr;
+    Entry.Function = RelocateOrElse(FuncOff, Extractor.getU64(&OffsetPtr));
     auto Kind = Extractor.getU8(&OffsetPtr);
     static constexpr SledEntry::FunctionKinds Kinds[] = {
         SledEntry::FunctionKinds::ENTRY, SledEntry::FunctionKinds::EXIT,