[codeview] Use character types for all byte-sized integer types

The VS debugger doesn't appear to understand the 0x68 or 0x69 type
indices, which were probably intended for use on a platform where a C
'int' is 8 bits. So, use the character types instead. Clang was already
using the character types because '[u]int8_t' is usually defined in
terms of 'char'.

See the Rust issue for screenshots of what VS does:
rust-lang/rust#36646

Fixes PR30552

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282739 91177308-0d34-0410-b5e6-96231b3b80d8

Author: rnk

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -1222,20 +1222,20 @@ TypeIndex CodeViewDebug::lowerTypeBasic(const DIBasicType *Ty) {
     break;
   case dwarf::DW_ATE_signed:
     switch (ByteSize) {
-    case 1:  STK = SimpleTypeKind::SByte;      break;
-    case 2:  STK = SimpleTypeKind::Int16Short; break;
-    case 4:  STK = SimpleTypeKind::Int32;      break;
-    case 8:  STK = SimpleTypeKind::Int64Quad;  break;
-    case 16: STK = SimpleTypeKind::Int128Oct;  break;
+    case 1:  STK = SimpleTypeKind::SignedCharacter; break;
+    case 2:  STK = SimpleTypeKind::Int16Short;      break;
+    case 4:  STK = SimpleTypeKind::Int32;           break;
+    case 8:  STK = SimpleTypeKind::Int64Quad;       break;
+    case 16: STK = SimpleTypeKind::Int128Oct;       break;
     }
     break;
   case dwarf::DW_ATE_unsigned:
     switch (ByteSize) {
-    case 1:  STK = SimpleTypeKind::Byte;        break;
-    case 2:  STK = SimpleTypeKind::UInt16Short; break;
-    case 4:  STK = SimpleTypeKind::UInt32;      break;
-    case 8:  STK = SimpleTypeKind::UInt64Quad;  break;
-    case 16: STK = SimpleTypeKind::UInt128Oct;  break;
+    case 1:  STK = SimpleTypeKind::UnsignedCharacter; break;
+    case 2:  STK = SimpleTypeKind::UInt16Short;       break;
+    case 4:  STK = SimpleTypeKind::UInt32;            break;
+    case 8:  STK = SimpleTypeKind::UInt64Quad;        break;
+    case 16: STK = SimpleTypeKind::UInt128Oct;        break;
     }
     break;
   case dwarf::DW_ATE_UTF:

test/DebugInfo/COFF/int8-char-type.ll

@@ -0,0 +1,55 @@
+; RUN: llc < %s -filetype=obj | llvm-readobj - -codeview | FileCheck %s
+
+; Use character types for all 8-bit integers. The VS debugger doesn't cope well
+; with the T_[U]INT1 types. Non-C language frontends are likely use the normal
+; DW_ATE_[un]signed encoding for all integer types if they don't have distinct
+; integer types for characters types. This was PR30552.
+
+; CHECK-LABEL: DataSym {
+; CHECK-NEXT:    Kind: S_GDATA32 (0x110D)
+; CHECK-NEXT:    DataOffset:
+; CHECK-NEXT:    Type: signed char (0x10)
+; CHECK-NEXT:    DisplayName: x
+; CHECK-NEXT:    LinkageName: x
+; CHECK-NEXT:  }
+
+; CHECK-LABEL: DataSym {
+; CHECK-NEXT:    Kind: S_GDATA32 (0x110D)
+; CHECK-NEXT:    DataOffset:
+; CHECK-NEXT:    Type: unsigned char (0x20)
+; CHECK-NEXT:    DisplayName: y
+; CHECK-NEXT:    LinkageName: y
+; CHECK-NEXT:  }
+
+source_filename = "-"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.0.24210"
+
+@x = global i8 0, align 1, !dbg !0
+@y = global i8 0, align 1, !dbg !5
+
+!llvm.dbg.cu = !{!1}
+!llvm.module.flags = !{!11, !12, !13}
+!llvm.ident = !{!14}
+
+!0 = distinct !DIGlobalVariable(name: "x", scope: !1, file: !6, line: 4, type: !9, isLocal: false, isDefinition: true)
+!1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 4.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, globals: !4)
+!2 = !DIFile(filename: "-", directory: "C:\5Csrc\5Cllvm\5Cbuild")
+!3 = !{}
+!4 = !{!0, !5}
+!5 = distinct !DIGlobalVariable(name: "y", scope: !1, file: !6, line: 5, type: !7, isLocal: false, isDefinition: true)
+!6 = !DIFile(filename: "<stdin>", directory: "C:\5Csrc\5Cllvm\5Cbuild")
+!7 = !DIDerivedType(tag: DW_TAG_typedef, name: "uint8_t", file: !6, line: 3, baseType: !8)
+
+; Manually modified to use DW_ATE_unsigned
+!8 = !DIBasicType(size: 8, align: 8, encoding: DW_ATE_unsigned)
+
+!9 = !DIDerivedType(tag: DW_TAG_typedef, name: "int8_t", file: !6, line: 2, baseType: !10)
+
+; Manually modified to use DW_ATE_signed
+!10 = !DIBasicType(size: 8, align: 8, encoding: DW_ATE_signed)
+
+!11 = !{i32 2, !"CodeView", i32 1}
+!12 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = !{i32 1, !"PIC Level", i32 2}
+!14 = !{!"clang version 4.0.0 "}