1 files changed, 17 insertions, 6 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index ea836469771..b3dabca0a8a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -2633,6 +2633,17 @@ void CodeViewDebug::emitLocalVariableList(const FunctionInfo &FI,
       emitLocalVariable(FI, L);
 }
 
+/// Only call this on endian-specific types like ulittle16_t and little32_t, or
+/// structs composed of them.
+template <typename T>
+static void copyBytesForDefRange(SmallString<20> &BytePrefix,
+                                 SymbolKind SymKind, const T &DefRangeHeader) {
+  BytePrefix.resize(2 + sizeof(T));
+  ulittle16_t SymKindLE = ulittle16_t(SymKind);
+  memcpy(&BytePrefix[0], &SymKindLE, 2);
+  memcpy(&BytePrefix[2], &DefRangeHeader, sizeof(T));
+}
+
 void CodeViewDebug::emitLocalVariable(const FunctionInfo &FI,
                                       const LocalVariable &Var) {
   // LocalSym record, see SymbolRecord.h for more info.
@@ -2681,9 +2692,8 @@ void CodeViewDebug::emitLocalVariable(const FunctionInfo &FI,
           (bool(Flags & LocalSymFlags::IsParameter)
                ? (EncFP == FI.EncodedParamFramePtrReg)
                : (EncFP == FI.EncodedLocalFramePtrReg))) {
-        DefRangeFramePointerRelSym::Header DRHdr;
-        DRHdr.Offset = Offset;
-        OS.EmitCVDefRangeDirective(DefRange.Ranges, DRHdr);
+        little32_t FPOffset = little32_t(Offset);
+        copyBytesForDefRange(BytePrefix, S_DEFRANGE_FRAMEPOINTER_REL, FPOffset);
       } else {
         uint16_t RegRelFlags = 0;
         if (DefRange.IsSubfield) {
@@ -2695,7 +2705,7 @@ void CodeViewDebug::emitLocalVariable(const FunctionInfo &FI,
         DRHdr.Register = Reg;
         DRHdr.Flags = RegRelFlags;
         DRHdr.BasePointerOffset = Offset;
-        OS.EmitCVDefRangeDirective(DefRange.Ranges, DRHdr);
+        copyBytesForDefRange(BytePrefix, S_DEFRANGE_REGISTER_REL, DRHdr);
       }
     } else {
       assert(DefRange.DataOffset == 0 && "unexpected offset into register");
@@ -2704,14 +2714,15 @@ void CodeViewDebug::emitLocalVariable(const FunctionInfo &FI,
         DRHdr.Register = DefRange.CVRegister;
         DRHdr.MayHaveNoName = 0;
         DRHdr.OffsetInParent = DefRange.StructOffset;
-        OS.EmitCVDefRangeDirective(DefRange.Ranges, DRHdr);
+        copyBytesForDefRange(BytePrefix, S_DEFRANGE_SUBFIELD_REGISTER, DRHdr);
       } else {
         DefRangeRegisterSym::Header DRHdr;
         DRHdr.Register = DefRange.CVRegister;
         DRHdr.MayHaveNoName = 0;
-        OS.EmitCVDefRangeDirective(DefRange.Ranges, DRHdr);
+        copyBytesForDefRange(BytePrefix, S_DEFRANGE_REGISTER, DRHdr);
       }
     }
+    OS.EmitCVDefRangeDirective(DefRange.Ranges, BytePrefix);
   }
 }