Index: include/llvm/CodeGen/DIE.h
===================================================================
--- include/llvm/CodeGen/DIE.h
+++ include/llvm/CodeGen/DIE.h
@@ -759,7 +759,7 @@
   ///
   /// \returns the DIEUnit that represents the compile or type unit that owns
   /// this DIE, or NULL if this DIE hasn't been added to a unit DIE.
-  const DIEUnit *getUnit() const;
+  DIEUnit *getUnit() const;
 
   void setOffset(unsigned O) { Offset = O; }
   void setSize(unsigned S) { Size = S; }
Index: lib/CodeGen/AsmPrinter/DIE.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DIE.cpp
+++ lib/CodeGen/AsmPrinter/DIE.cpp
@@ -211,7 +211,7 @@
   return nullptr;
 }
 
-const DIEUnit *DIE::getUnit() const {
+DIEUnit *DIE::getUnit() const {
   const DIE *UnitDie = getUnitDie();
   if (UnitDie)
     return UnitDie->Owner.dyn_cast<DIEUnit*>();
Index: lib/CodeGen/AsmPrinter/DwarfUnit.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1106,7 +1106,8 @@
   if (SP->isDefinition())
     return &SPDie;
 
-  applySubprogramAttributes(SP, SPDie);
+  static_cast<DwarfUnit *>(SPDie.getUnit())
+      ->applySubprogramAttributes(SP, SPDie);
   return &SPDie;
 }
 
Index: test/DebugInfo/X86/template_function_decl.ll
===================================================================
--- test/DebugInfo/X86/template_function_decl.ll
+++ test/DebugInfo/X86/template_function_decl.ll
@@ -0,0 +1,153 @@
+; Checks that we correctly set DW_AT_decl_file attribute for
+; template function declaration. When using full LTO we likely
+; end up having multiple CUs in a single DWARF file, and it is
+; possible that we add template function declaration DIE from
+; CU#1 to structure type DIE from CU#2. In such case we should
+; add source line attributes on behalf of CU#2, not CU#1
+
+; Example source code used to generate this sample (C++)
+; // File: inc1.h
+; struct S {
+;   int foo;
+;   template <class T> T squared(T val) { return val * val; }
+; };
+;
+; // File: inc2.h
+; struct S2 { int q, v; };
+;
+; // File: foo.cpp
+; #include "inc1.h"
+; S s_foo;
+; extern int bar(int);
+; int main() {
+;    return bar(s_foo.foo);
+; }
+; 
+; // File: bar.cpp
+; #include "inc2.h"
+; #include "inc1.h"
+; struct S gs_bar;
+; struct S2 gs2_bar;
+; int bar(int v) {
+;   return gs_bar.squared(v);
+; }
+
+; RUN: llc -filetype=obj %s -o %t
+; RUN: llvm-dwarfdump %t -o - | FileCheck %s
+
+; CHECK:       DW_AT_linkage_name ("_ZN1S7squaredIiEET_S1_")
+; CHECK-NEXT:  DW_AT_name ("squared<int>")
+; CHECK-NEXT:  DW_AT_decl_file ("{{.*}}inc1.h")
+; CHECK-NEXT:  DW_AT_decl_line (3)
+
+source_filename = "ld-temp.o"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.S = type { i32 }
+
+$_ZN1S7squaredIiEET_S1_ = comdat any
+
+@s_foo = internal global %struct.S zeroinitializer, align 4, !dbg !0
+@gs_bar = internal global %struct.S zeroinitializer, align 4, !dbg !11
+
+; Function Attrs: noinline norecurse optnone uwtable
+define dso_local i32 @main() !dbg !29 {
+  %1 = alloca i32, align 4
+  store i32 0, i32* %1, align 4
+  %2 = load i32, i32* getelementptr inbounds (%struct.S, %struct.S* @s_foo, i32 0, i32 0), align 4, !dbg !32
+  %3 = call i32 @_Z3bari(i32 %2), !dbg !33
+  ret i32 %3, !dbg !34
+}
+
+; Function Attrs: noinline optnone uwtable
+define internal i32 @_Z3bari(i32) !dbg !35 {
+  %2 = alloca i32, align 4
+  store i32 %0, i32* %2, align 4
+  call void @llvm.dbg.declare(metadata i32* %2, metadata !38, metadata !DIExpression()), !dbg !39
+  %3 = load i32, i32* %2, align 4, !dbg !40
+  %4 = call i32 @_ZN1S7squaredIiEET_S1_(%struct.S* @gs_bar, i32 %3), !dbg !41
+  ret i32 %4, !dbg !42
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+; Function Attrs: noinline nounwind optnone uwtable
+define internal i32 @_ZN1S7squaredIiEET_S1_(%struct.S*, i32) comdat align 2 !dbg !43 {
+  %3 = alloca %struct.S*, align 8
+  %4 = alloca i32, align 4
+  store %struct.S* %0, %struct.S** %3, align 8
+  call void @llvm.dbg.declare(metadata %struct.S** %3, metadata !50, metadata !DIExpression()), !dbg !52
+  store i32 %1, i32* %4, align 4
+  call void @llvm.dbg.declare(metadata i32* %4, metadata !53, metadata !DIExpression()), !dbg !54
+  %5 = load %struct.S*, %struct.S** %3, align 8
+  %6 = load i32, i32* %4, align 4, !dbg !55
+  %7 = load i32, i32* %4, align 4, !dbg !56
+  %8 = mul nsw i32 %6, %7, !dbg !57
+  ret i32 %8, !dbg !58
+}
+
+!llvm.dbg.cu = !{!2, !13}
+!llvm.ident = !{!23, !23}
+!llvm.module.flags = !{!24, !25, !26, !27, !28}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "s_foo", scope: !2, file: !3, line: 3, type: !6, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 9.0.0 (trunk 353925)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
+!3 = !DIFile(filename: "foo.cpp", directory: "/home/evgeny/work/cpp_lexer/sample2")
+!4 = !{}
+!5 = !{!0}
+!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !7, line: 1, size: 32, flags: DIFlagTypePassByValue | DIFlagTrivial, elements: !8, identifier: "_ZTS1S")
+!7 = !DIFile(filename: "./inc1.h", directory: "/home/evgeny/work/cpp_lexer/sample2")
+!8 = !{!9}
+!9 = !DIDerivedType(tag: DW_TAG_member, name: "foo", scope: !6, file: !7, line: 2, baseType: !10, size: 32)
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DIGlobalVariableExpression(var: !12, expr: !DIExpression())
+!12 = distinct !DIGlobalVariable(name: "gs_bar", scope: !13, file: !14, line: 4, type: !6, isLocal: false, isDefinition: true)
+!13 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !14, producer: "clang version 9.0.0 (trunk 353925)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !15, nameTableKind: None)
+!14 = !DIFile(filename: "bar.cpp", directory: "/home/evgeny/work/cpp_lexer/sample2")
+!15 = !{!11, !16}
+!16 = !DIGlobalVariableExpression(var: !17, expr: !DIExpression())
+!17 = distinct !DIGlobalVariable(name: "gs2_bar", scope: !13, file: !14, line: 5, type: !18, isLocal: false, isDefinition: true)
+!18 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S2", file: !19, line: 1, size: 64, flags: DIFlagTypePassByValue | DIFlagTrivial, elements: !20, identifier: "_ZTS2S2")
+!19 = !DIFile(filename: "./inc2.h", directory: "/home/evgeny/work/cpp_lexer/sample2")
+!20 = !{!21, !22}
+!21 = !DIDerivedType(tag: DW_TAG_member, name: "q", scope: !18, file: !19, line: 2, baseType: !10, size: 32)
+!22 = !DIDerivedType(tag: DW_TAG_member, name: "v", scope: !18, file: !19, line: 2, baseType: !10, size: 32, offset: 32)
+!23 = !{!"clang version 9.0.0 (trunk 353925)"}
+!24 = !{i32 2, !"Dwarf Version", i32 4}
+!25 = !{i32 2, !"Debug Info Version", i32 3}
+!26 = !{i32 1, !"wchar_size", i32 4}
+!27 = !{i32 1, !"ThinLTO", i32 0}
+!28 = !{i32 1, !"EnableSplitLTOUnit", i32 0}
+!29 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 6, type: !30, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !4)
+!30 = !DISubroutineType(types: !31)
+!31 = !{!10}
+!32 = !DILocation(line: 7, column: 20, scope: !29)
+!33 = !DILocation(line: 7, column: 10, scope: !29)
+!34 = !DILocation(line: 7, column: 3, scope: !29)
+!35 = distinct !DISubprogram(name: "bar", linkageName: "_Z3bari", scope: !14, file: !14, line: 7, type: !36, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !13, retainedNodes: !4)
+!36 = !DISubroutineType(types: !37)
+!37 = !{!10, !10}
+!38 = !DILocalVariable(name: "v", arg: 1, scope: !35, file: !14, line: 7, type: !10)
+!39 = !DILocation(line: 7, column: 13, scope: !35)
+!40 = !DILocation(line: 8, column: 25, scope: !35)
+!41 = !DILocation(line: 8, column: 17, scope: !35)
+!42 = !DILocation(line: 8, column: 3, scope: !35)
+!43 = distinct !DISubprogram(name: "squared<int>", linkageName: "_ZN1S7squaredIiEET_S1_", scope: !6, file: !7, line: 3, type: !44, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !13, templateParams: !48, declaration: !47, retainedNodes: !4)
+!44 = !DISubroutineType(types: !45)
+!45 = !{!10, !46, !10}
+!46 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
+!47 = !DISubprogram(name: "squared<int>", linkageName: "_ZN1S7squaredIiEET_S1_", scope: !6, file: !7, line: 3, type: !44, scopeLine: 3, flags: DIFlagPrototyped, spFlags: 0, templateParams: !48)
+!48 = !{!49}
+!49 = !DITemplateTypeParameter(name: "T", type: !10)
+!50 = !DILocalVariable(name: "this", arg: 1, scope: !43, type: !51, flags: DIFlagArtificial | DIFlagObjectPointer)
+!51 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64)
+!52 = !DILocation(line: 0, scope: !43)
+!53 = !DILocalVariable(name: "val", arg: 2, scope: !43, file: !7, line: 3, type: !10)
+!54 = !DILocation(line: 3, column: 34, scope: !43)
+!55 = !DILocation(line: 3, column: 48, scope: !43)
+!56 = !DILocation(line: 3, column: 54, scope: !43)
+!57 = !DILocation(line: 3, column: 52, scope: !43)
+!58 = !DILocation(line: 3, column: 41, scope: !43)