diff --git a/lib/Target/BPF/BTFDebug.cpp b/lib/Target/BPF/BTFDebug.cpp
index 3f55313..5d1d96f 100644
--- a/lib/Target/BPF/BTFDebug.cpp
+++ b/lib/Target/BPF/BTFDebug.cpp
@@ -658,12 +658,12 @@
   std::unordered_map<uint32_t, StringRef> FuncArgNames;
   for (const DINode *DN : SP->getRetainedNodes()) {
     if (const auto *DV = dyn_cast<DILocalVariable>(DN)) {
-      visitTypeEntry(DV->getType().resolve());
-
       // Collect function arguments for subprogram func type.
       uint32_t Arg = DV->getArg();
-      if (Arg)
+      if (Arg) {
+        visitTypeEntry(DV->getType().resolve());
         FuncArgNames[Arg] = DV->getName();
+      }
     }
   }
 
@@ -749,10 +749,15 @@
 void BTFDebug::endModule() {
   // Collect all types referenced by globals.
   const Module *M = MMI->getModule();
-  for (const DICompileUnit *CUNode : M->debug_compile_units()) {
-    for (const auto *GVE : CUNode->getGlobalVariables()) {
-      DIGlobalVariable *GV = GVE->getVariable();
-      visitTypeEntry(GV->getType().resolve());
+  for (const GlobalVariable &Global : M->globals()) {
+    // Ignore external globals for now.
+    if (Global.hasExternalLinkage())
+      continue;
+
+    SmallVector<DIGlobalVariableExpression *, 1> GVs;
+    Global.getDebugInfo(GVs);
+    for (auto *GVE : GVs) {
+      visitTypeEntry(GVE->getVariable()->getType().resolve());
     }
   }
 
diff --git a/test/CodeGen/BPF/BTF/extern-global-var.ll b/test/CodeGen/BPF/BTF/extern-global-var.ll
new file mode 100644
index 0000000..ad81d28
--- /dev/null
+++ b/test/CodeGen/BPF/BTF/extern-global-var.ll
@@ -0,0 +1,69 @@
+; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
+; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
+
+; Source code:
+;   extern char a;
+;   int foo() { return a; }
+; Compilation flag:
+;   clang -target bpf -O2 -g -S -emit-llvm test.c
+
+@a = external dso_local local_unnamed_addr global i8, align 1
+
+; Function Attrs: norecurse nounwind readonly
+define dso_local i32 @foo() local_unnamed_addr #0 !dbg !7 {
+  %1 = load i8, i8* @a, align 1, !dbg !11, !tbaa !12
+  %2 = sext i8 %1 to i32, !dbg !11
+  ret i32 %2, !dbg !15
+}
+
+; CHECK:             .section        .BTF,"",@progbits
+; CHECK-NEXT:        .short  60319                   # 0xeb9f
+; CHECK-NEXT:        .byte   1
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .long   24
+; CHECK-NEXT:        .long   0
+; CHECK-NEXT:        .long   40
+; CHECK-NEXT:        .long   40
+; CHECK-NEXT:        .long   52
+; CHECK-NEXT:        .long   0                       # BTF_KIND_FUNC_PROTO(id = 1)
+; CHECK-NEXT:        .long   218103808               # 0xd000000
+; CHECK-NEXT:        .long   2
+; CHECK-NEXT:        .long   44                      # BTF_KIND_INT(id = 2)
+; CHECK-NEXT:        .long   16777216                # 0x1000000
+; CHECK-NEXT:        .long   4
+; CHECK-NEXT:        .long   16777248                # 0x1000020
+; CHECK-NEXT:        .long   48                      # BTF_KIND_FUNC(id = 3)
+; CHECK-NEXT:        .long   201326592               # 0xc000000
+; CHECK-NEXT:        .long   1
+; CHECK-NEXT:        .byte   0                       # string offset=0
+; CHECK-NEXT:        .ascii  ".text"                 # string offset=1
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "/home/yhs/work/tests/llvm/bug/test.c" # string offset=7
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "int"                   # string offset=44
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "foo"                   # string offset=48
+; CHECK-NEXT:        .byte   0
+
+attributes #0 = { norecurse nounwind readonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 8.0.20181009 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "test.c", directory: "/home/yhs/work/tests/llvm/bug")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 8.0.20181009 "}
+!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, type: !8, isLocal: false, isDefinition: true, scopeLine: 2, isOptimized: true, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DILocation(line: 2, column: 20, scope: !7)
+!12 = !{!13, !13, i64 0}
+!13 = !{!"omnipotent char", !14, i64 0}
+!14 = !{!"Simple C/C++ TBAA"}
+!15 = !DILocation(line: 2, column: 13, scope: !7)
diff --git a/test/CodeGen/BPF/BTF/local-var.ll b/test/CodeGen/BPF/BTF/local-var.ll
new file mode 100644
index 0000000..4eb498a
--- /dev/null
+++ b/test/CodeGen/BPF/BTF/local-var.ll
@@ -0,0 +1,108 @@
+; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
+; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
+
+; Source code:
+;   int foo(char a) { volatile short b = 0;  return b; }
+; Compilation flag:
+;   clang -target bpf -O2 -g -S -emit-llvm test.c
+
+; Function Attrs: nounwind
+define dso_local i32 @foo(i8 signext) local_unnamed_addr #0 !dbg !7 {
+  %2 = alloca i16, align 2
+  call void @llvm.dbg.value(metadata i8 %0, metadata !13, metadata !DIExpression()), !dbg !17
+  %3 = bitcast i16* %2 to i8*, !dbg !18
+  call void @llvm.lifetime.start.p0i8(i64 2, i8* nonnull %3), !dbg !18
+  call void @llvm.dbg.declare(metadata i16* %2, metadata !14, metadata !DIExpression()), !dbg !19
+  store volatile i16 0, i16* %2, align 2, !dbg !19, !tbaa !20
+  %4 = load volatile i16, i16* %2, align 2, !dbg !24, !tbaa !20
+  %5 = sext i16 %4 to i32, !dbg !24
+  call void @llvm.lifetime.end.p0i8(i64 2, i8* nonnull %3), !dbg !25
+  ret i32 %5, !dbg !26
+}
+
+; CHECK:             .section        .BTF,"",@progbits
+; CHECK-NEXT:        .short  60319                   # 0xeb9f
+; CHECK-NEXT:        .byte   1
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .long   24
+; CHECK-NEXT:        .long   0
+; CHECK-NEXT:        .long   64
+; CHECK-NEXT:        .long   64
+; CHECK-NEXT:        .long   59
+; CHECK-NEXT:        .long   44                      # BTF_KIND_INT(id = 1)
+; CHECK-NEXT:        .long   16777216                # 0x1000000
+; CHECK-NEXT:        .long   1
+; CHECK-NEXT:        .long   16777224                # 0x1000008
+; CHECK-NEXT:        .long   0                       # BTF_KIND_FUNC_PROTO(id = 2)
+; CHECK-NEXT:        .long   218103809               # 0xd000001
+; CHECK-NEXT:        .long   3
+; CHECK-NEXT:        .long   49
+; CHECK-NEXT:        .long   1
+; CHECK-NEXT:        .long   51                      # BTF_KIND_INT(id = 3)
+; CHECK-NEXT:        .long   16777216                # 0x1000000
+; CHECK-NEXT:        .long   4
+; CHECK-NEXT:        .long   16777248                # 0x1000020
+; CHECK-NEXT:        .long   55                      # BTF_KIND_FUNC(id = 4)
+; CHECK-NEXT:        .long   201326592               # 0xc000000
+; CHECK-NEXT:        .long   2
+; CHECK-NEXT:        .byte   0                       # string offset=0
+; CHECK-NEXT:        .ascii  ".text"                 # string offset=1
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "/home/yhs/work/tests/llvm/bug/test.c" # string offset=7
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "char"                  # string offset=44
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .byte   97                      # string offset=49
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "int"                   # string offset=51
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "foo"                   # string offset=55
+; CHECK-NEXT:        .byte   0
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #2
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #2
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone speculatable }
+attributes #2 = { argmemonly nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 8.0.20181009 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "test.c", directory: "/home/yhs/work/tests/llvm/bug")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 8.0.20181009 "}
+!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !12)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10, !11}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!12 = !{!13, !14}
+!13 = !DILocalVariable(name: "a", arg: 1, scope: !7, file: !1, line: 1, type: !11)
+!14 = !DILocalVariable(name: "b", scope: !7, file: !1, line: 1, type: !15)
+!15 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !16)
+!16 = !DIBasicType(name: "short", size: 16, encoding: DW_ATE_signed)
+!17 = !DILocation(line: 1, column: 14, scope: !7)
+!18 = !DILocation(line: 1, column: 19, scope: !7)
+!19 = !DILocation(line: 1, column: 34, scope: !7)
+!20 = !{!21, !21, i64 0}
+!21 = !{!"short", !22, i64 0}
+!22 = !{!"omnipotent char", !23, i64 0}
+!23 = !{!"Simple C/C++ TBAA"}
+!24 = !DILocation(line: 1, column: 49, scope: !7)
+!25 = !DILocation(line: 1, column: 52, scope: !7)
+!26 = !DILocation(line: 1, column: 42, scope: !7)
diff --git a/test/CodeGen/BPF/BTF/static-var.ll b/test/CodeGen/BPF/BTF/static-var.ll
new file mode 100644
index 0000000..3fff7a2
--- /dev/null
+++ b/test/CodeGen/BPF/BTF/static-var.ll
@@ -0,0 +1,107 @@
+; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
+; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
+
+; Source code:
+;   static volatile char a;
+;   int foo() {
+;     static volatile short b;
+;     return a + b;
+;   }
+; Compilation flag:
+;   clang -target bpf -O2 -g -S -emit-llvm test.c
+
+@foo.b = internal global i16 0, align 2, !dbg !0
+@a = internal global i8 0, align 1, !dbg !10
+
+; Function Attrs: norecurse nounwind
+define dso_local i32 @foo() local_unnamed_addr #0 !dbg !2 {
+  %1 = load volatile i8, i8* @a, align 1, !dbg !20, !tbaa !21
+  %2 = sext i8 %1 to i32, !dbg !20
+  %3 = load volatile i16, i16* @foo.b, align 2, !dbg !24, !tbaa !25
+  %4 = sext i16 %3 to i32, !dbg !24
+  %5 = add nsw i32 %4, %2, !dbg !27
+  ret i32 %5, !dbg !28
+}
+
+; CHECK:             .section        .BTF,"",@progbits
+; CHECK-NEXT:        .short  60319                   # 0xeb9f
+; CHECK-NEXT:        .byte   1
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .long   24
+; CHECK-NEXT:        .long   0
+; CHECK-NEXT:        .long   96
+; CHECK-NEXT:        .long   96
+; CHECK-NEXT:        .long   63
+; CHECK-NEXT:        .long   0                       # BTF_KIND_FUNC_PROTO(id = 1)
+; CHECK-NEXT:        .long   218103808               # 0xd000000
+; CHECK-NEXT:        .long   2
+; CHECK-NEXT:        .long   44                      # BTF_KIND_INT(id = 2)
+; CHECK-NEXT:        .long   16777216                # 0x1000000
+; CHECK-NEXT:        .long   4
+; CHECK-NEXT:        .long   16777248                # 0x1000020
+; CHECK-NEXT:        .long   48                      # BTF_KIND_FUNC(id = 3)
+; CHECK-NEXT:        .long   201326592               # 0xc000000
+; CHECK-NEXT:        .long   1
+; CHECK-NEXT:        .long   0                       # BTF_KIND_VOLATILE(id = 4)
+; CHECK-NEXT:        .long   150994944               # 0x9000000
+; CHECK-NEXT:        .long   5
+; CHECK-NEXT:        .long   52                      # BTF_KIND_INT(id = 5)
+; CHECK-NEXT:        .long   16777216                # 0x1000000
+; CHECK-NEXT:        .long   2
+; CHECK-NEXT:        .long   16777232                # 0x1000010
+; CHECK-NEXT:        .long   0                       # BTF_KIND_VOLATILE(id = 6)
+; CHECK-NEXT:        .long   150994944               # 0x9000000
+; CHECK-NEXT:        .long   7
+; CHECK-NEXT:        .long   58                      # BTF_KIND_INT(id = 7)
+; CHECK-NEXT:        .long   16777216                # 0x1000000
+; CHECK-NEXT:        .long   1
+; CHECK-NEXT:        .long   16777224                # 0x1000008
+; CHECK-NEXT:        .byte   0                       # string offset=0
+; CHECK-NEXT:        .ascii  ".text"                 # string offset=1
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "/home/yhs/work/tests/llvm/bug/test.c" # string offset=7
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "int"                   # string offset=44
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "foo"                   # string offset=48
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "short"                 # string offset=52
+; CHECK-NEXT:        .byte   0
+; CHECK-NEXT:        .ascii  "char"                  # string offset=58
+; CHECK-NEXT:        .byte   0
+
+attributes #0 = { norecurse nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!7}
+!llvm.module.flags = !{!16, !17, !18}
+!llvm.ident = !{!19}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !3, line: 3, type: !14, isLocal: true, isDefinition: true)
+!2 = distinct !DISubprogram(name: "foo", scope: !3, file: !3, line: 2, type: !4, isLocal: false, isDefinition: true, scopeLine: 2, isOptimized: true, unit: !7, retainedNodes: !8)
+!3 = !DIFile(filename: "test.c", directory: "/home/yhs/work/tests/llvm/bug")
+!4 = !DISubroutineType(types: !5)
+!5 = !{!6}
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 8.0.20181009 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !8, globals: !9, nameTableKind: None)
+!8 = !{}
+!9 = !{!0, !10}
+!10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression())
+!11 = distinct !DIGlobalVariable(name: "a", scope: !7, file: !3, line: 1, type: !12, isLocal: true, isDefinition: true)
+!12 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !13)
+!13 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!14 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !15)
+!15 = !DIBasicType(name: "short", size: 16, encoding: DW_ATE_signed)
+!16 = !{i32 2, !"Dwarf Version", i32 4}
+!17 = !{i32 2, !"Debug Info Version", i32 3}
+!18 = !{i32 1, !"wchar_size", i32 4}
+!19 = !{!"clang version 8.0.20181009 "}
+!20 = !DILocation(line: 4, column: 10, scope: !2)
+!21 = !{!22, !22, i64 0}
+!22 = !{!"omnipotent char", !23, i64 0}
+!23 = !{!"Simple C/C++ TBAA"}
+!24 = !DILocation(line: 4, column: 14, scope: !2)
+!25 = !{!26, !26, i64 0}
+!26 = !{!"short", !22, i64 0}
+!27 = !DILocation(line: 4, column: 12, scope: !2)
+!28 = !DILocation(line: 4, column: 3, scope: !2)