DI: Remove DW_TAG_arg_variable and DW_TAG_auto_variable

Remove the fake `DW_TAG_auto_variable` and `DW_TAG_arg_variable` tags,
using `DW_TAG_variable` in their place Stop exposing the `tag:` field at
all in the assembly format for `DILocalVariable`.

Most of the testcase updates were generated by the following sed script:

    find test/ -name "*.ll" -o -name "*.mir" |
    xargs grep -l 'DILocalVariable' |
    xargs sed -i '' \
      -e 's/tag: DW_TAG_arg_variable, //' \
      -e 's/tag: DW_TAG_auto_variable, //'

There were only a handful of tests in `test/Assembly` that I needed to
update by hand.

(Note: a follow-up could change `DILocalVariable::DILocalVariable()` to
set the tag to `DW_TAG_formal_parameter` instead of `DW_TAG_variable`
(as appropriate), instead of having that logic magically in the backend
in `DbgVariable`.  I've added a FIXME to that effect.)

llvm-svn: 243774
diff --git a/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll b/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll
index aff2e60..3cbbbf6 100644
--- a/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll
+++ b/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll
@@ -32,7 +32,7 @@
 
 !llvm.dbg.cu = !{!3}
 !llvm.module.flags = !{!22}
-!0 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "a", line: 8, arg: 1, scope: !1, file: !2, type: !6)
+!0 = !DILocalVariable(name: "a", line: 8, arg: 1, scope: !1, file: !2, type: !6)
 !1 = !DISubprogram(name: "baz", linkageName: "baz", line: 8, isLocal: false, isDefinition: true, virtualIndex: 6, isOptimized: false, scopeLine: 8, file: !20, scope: !2, type: !4, function: void (i32)* @baz)
 !2 = !DIFile(filename: "bar.c", directory: "/tmp/")
 !3 = !DICompileUnit(language: DW_LANG_C89, producer: "4.2.1 (Based on Apple Inc. build 5658) (LLVM build)", isOptimized: true, emissionKind: 0, file: !20, enums: !21, retainedTypes: !21)
@@ -41,15 +41,15 @@
 !6 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !7 = !DILocation(line: 8, scope: !1)
 !8 = !DILocation(line: 9, scope: !1)
-!9 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "x", line: 4, arg: 1, scope: !10, file: !2, type: !6)
+!9 = !DILocalVariable(name: "x", line: 4, arg: 1, scope: !10, file: !2, type: !6)
 !10 = !DISubprogram(name: "bar", linkageName: "bar", line: 4, isLocal: true, isDefinition: true, virtualIndex: 6, isOptimized: false, scopeLine: 4, file: !20, scope: !2, type: !11)
 !11 = !DISubroutineType(types: !12)
 !12 = !{null, !6, !13, !14}
 !13 = !DIBasicType(tag: DW_TAG_base_type, name: "long int", size: 64, align: 64, encoding: DW_ATE_signed)
 !14 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, file: !20, scope: !2, baseType: null)
 !15 = !DILocation(line: 4, scope: !10, inlinedAt: !8)
-!16 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "y", line: 4, arg: 2, scope: !10, file: !2, type: !13)
-!17 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "z", line: 4, arg: 3, scope: !10, file: !2, type: !14)
+!16 = !DILocalVariable(name: "y", line: 4, arg: 2, scope: !10, file: !2, type: !13)
+!17 = !DILocalVariable(name: "z", line: 4, arg: 3, scope: !10, file: !2, type: !14)
 !18 = !DILocation(line: 5, scope: !10, inlinedAt: !8)
 !19 = !DILocation(line: 10, scope: !1)
 !20 = !DIFile(filename: "bar.c", directory: "/tmp/")