[IRGen] [DebugInfo] Ignore autogenerated flag for variables

Author: Snowy1803

include/swift/SIL/SILLocation.h

@@ -391,6 +391,16 @@ class SILLocation {
   /// Check is this location is part of a function's implicit prologue.
   bool isInPrologue() const { return kindAndFlags.fields.inPrologue; }
 
+  /// Returns this location with the auto-generated and prologue bits stripped.
+  /// These bits only make sense for instructions, and should be stripped for
+  /// variables.
+  SILLocation strippedForDebugVariable() const {
+    SILLocation loc = *this;
+    loc.kindAndFlags.fields.autoGenerated = false;
+    loc.kindAndFlags.fields.inPrologue = false;
+    return loc;
+  }
+
   /// Check if the corresponding source code location definitely points
   ///  to the end of the AST node.
   bool pointsToEnd() const;

lib/IRGen/IRGenDebugInfo.cpp

@@ -3186,10 +3186,14 @@ void IRGenDebugInfoImpl::emitVariableDeclaration(
   // Create the descriptor for the variable.
   unsigned DVarLine = DInstLine;
   uint16_t DVarCol = DInstLoc.Column;
-  if (VarInfo.Loc) {
-    auto DVarLoc = getStartLocation(VarInfo.Loc);
-    DVarLine = DVarLoc.Line;
-    DVarCol = DVarLoc.Column;
+  auto VarInfoLoc = VarInfo.Loc ? VarInfo.Loc : DbgInstLoc;
+  if (VarInfoLoc) {
+    auto VarLoc = VarInfoLoc->strippedForDebugVariable();
+    if (VarLoc != DbgInstLoc) {
+      auto DVarLoc = getStartLocation(VarLoc);
+      DVarLine = DVarLoc.Line;
+      DVarCol = DVarLoc.Column;
+    }
   }
   llvm::DIScope *VarScope = Scope;
   if (ArgNo == 0 && VarInfo.Scope) {