[CodeView] Implement support for bitfields in LLVM

CodeView need to know the offset of the storage allocation for a
bitfield.  Encode this via the "extraData" field in DIDerivedType and
introduced a new flag, DIFlagBitField, to indicate whether or not a
member is a bitfield.

This fixes PR28162.

Differential Revision: http://reviews.llvm.org/D21782

llvm-svn: 274200

1 files changed, 215 insertions, 0 deletions

diff --git a/llvm/test/DebugInfo/COFF/bitfields.ll b/llvm/test/DebugInfo/COFF/bitfields.ll
new file mode 100644
index 00000000000..b6fe2b3d706
--- /dev/null
+++ b/llvm/test/DebugInfo/COFF/bitfields.ll
@@ -0,0 +1,215 @@
+; RUN: llc < %s -filetype=obj | llvm-readobj - -codeview | FileCheck %s
+
+; C++ source to regenerate:
+; $ cat t.cpp
+; #pragma pack(1)
+; struct S0 {
+;   char : 8;
+;   short   : 8;
+;   short x : 8;
+; } s0;
+;
+; #pragma pack(1)
+; struct S1 {
+;   char x1[2];
+;   char x2;
+;   int y : 23;
+;   int z : 23;
+;   int w : 2;
+;   struct { char c; short s; } v;
+;   short u : 3;
+; } s1;
+;
+; #pragma pack(1)
+; struct S2 {
+;   char : 0;
+;   int y : 1;
+; } s2;
+; $ clang t.cpp -S -emit-llvm -g -gcodeview -o t.ll
+
+; CHECK: CodeViewTypes [
+; CHECK:  BitField ([[S0_x:.*]]) {
+; CHECK:    TypeLeafKind: LF_BITFIELD (0x1205)
+; CHECK:    Type: short (0x11)
+; CHECK:    BitSize: 8
+; CHECK:    BitOffset: 8
+; CHECK:  }
+; CHECK:  FieldList ([[S0_fl:.*]]) {
+; CHECK:    TypeLeafKind: LF_FIELDLIST (0x1203)
+; CHECK:    DataMember {
+; CHECK:      Type: [[S0_x:.*]]
+; CHECK:      FieldOffset: 0x1
+; CHECK:      Name: x
+; CHECK:    }
+; CHECK:  }
+; CHECK:  Struct ({{.*}}) {
+; CHECK:    TypeLeafKind: LF_STRUCTURE (0x1505)
+; CHECK:    MemberCount: 1
+; CHECK:    Properties [ (0x0)
+; CHECK:    ]
+; CHECK:    FieldList: <field list> ([[S0_fl]])
+; CHECK:    SizeOf: 3
+; CHECK:    Name: S0
+; CHECK:  }
+; CHECK:  BitField ([[S1_y_z:.*]]) {
+; CHECK:    TypeLeafKind: LF_BITFIELD (0x1205)
+; CHECK:    Type: int (0x74)
+; CHECK:    BitSize: 23
+; CHECK:    BitOffset: 0
+; CHECK:  }
+; CHECK:  BitField ([[S1_w:.*]]) {
+; CHECK:    TypeLeafKind: LF_BITFIELD (0x1205)
+; CHECK:    Type: int (0x74)
+; CHECK:    BitSize: 2
+; CHECK:    BitOffset: 23
+; CHECK:  }
+; CHECK:  BitField ([[S1_u:.*]]) {
+; CHECK:    TypeLeafKind: LF_BITFIELD (0x1205)
+; CHECK:    Type: short (0x11)
+; CHECK:    BitSize: 3
+; CHECK:    BitOffset: 0
+; CHECK:  }
+; CHECK:  FieldList ([[S1_fl:.*]]) {
+; CHECK:    TypeLeafKind: LF_FIELDLIST (0x1203)
+; CHECK:    DataMember {
+; CHECK:      FieldOffset: 0x0
+; CHECK:      Name: x1
+; CHECK:    }
+; CHECK:    DataMember {
+; CHECK:      Type: char (0x70)
+; CHECK:      FieldOffset: 0x2
+; CHECK:      Name: x2
+; CHECK:    }
+; CHECK:    DataMember {
+; CHECK:      Type: [[S1_y_z]]
+; CHECK:      FieldOffset: 0x3
+; CHECK:      Name: y
+; CHECK:    }
+; CHECK:    DataMember {
+; CHECK:      Type: [[S1_y_z]]
+; CHECK:      FieldOffset: 0x7
+; CHECK:      Name: z
+; CHECK:    }
+; CHECK:    DataMember {
+; CHECK:      Type: [[S1_w]]
+; CHECK:      FieldOffset: 0x7
+; CHECK:      Name: w
+; CHECK:    }
+; CHECK:    DataMember {
+; CHECK:      FieldOffset: 0xB
+; CHECK:      Name: v
+; CHECK:    }
+; CHECK:    DataMember {
+; CHECK:      Type: [[S1_u]]
+; CHECK:      FieldOffset: 0xE
+; CHECK:      Name: u
+; CHECK:    }
+; CHECK:  }
+; CHECK:  Struct ({{.*}}) {
+; CHECK:    TypeLeafKind: LF_STRUCTURE (0x1505)
+; CHECK:    MemberCount: 7
+; CHECK:    Properties [ (0x0)
+; CHECK:    ]
+; CHECK:    FieldList: <field list> ([[S1_fl]])
+; CHECK:    SizeOf: 16
+; CHECK:    Name: S1
+; CHECK:  }
+; CHECK:  FieldList ([[anon_fl:.*]]) {
+; CHECK:    TypeLeafKind: LF_FIELDLIST (0x1203)
+; CHECK:    DataMember {
+; CHECK:      Type: char (0x70)
+; CHECK:      FieldOffset: 0x0
+; CHECK:      Name: c
+; CHECK:    }
+; CHECK:    DataMember {
+; CHECK:      Type: short (0x11)
+; CHECK:      FieldOffset: 0x1
+; CHECK:      Name: s
+; CHECK:    }
+; CHECK:  }
+; CHECK:  Struct ({{.*}}) {
+; CHECK:    TypeLeafKind: LF_STRUCTURE (0x1505)
+; CHECK:    MemberCount: 2
+; CHECK:    Properties [ (0x0)
+; CHECK:    ]
+; CHECK:    FieldList: <field list> ([[anon_fl]])
+; CHECK:    SizeOf: 3
+; CHECK:    Name: S1::
+; CHECK:  }
+; CHECK:  BitField ([[S2_y:.*]]) {
+; CHECK:    TypeLeafKind: LF_BITFIELD (0x1205)
+; CHECK:    Type: int (0x74)
+; CHECK:    BitSize: 1
+; CHECK:    BitOffset: 0
+; CHECK:  }
+; CHECK:  FieldList ([[S2_fl:.*]]) {
+; CHECK:    TypeLeafKind: LF_FIELDLIST (0x1203)
+; CHECK:    DataMember {
+; CHECK:      Type: [[S2_y]]
+; CHECK:      FieldOffset: 0x0
+; CHECK:      Name: y
+; CHECK:    }
+; CHECK:  }
+; CHECK:  Struct ({{.*}}) {
+; CHECK:    TypeLeafKind: LF_STRUCTURE (0x1505)
+; CHECK:    MemberCount: 1
+; CHECK:    Properties [ (0x0)
+; CHECK:    ]
+; CHECK:    FieldList: <field list> ([[S2_fl]])
+; CHECK:    SizeOf: 4
+; CHECK:    Name: S2
+; CHECK:  }
+
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "x86_64-pc-windows-msvc18.0.0"
+
+%struct.S0 = type <{ i8, i16 }>
+%struct.S1 = type <{ [2 x i8], i8, i32, i32, %struct.anon, i16 }>
+%struct.anon = type <{ i8, i16 }>
+%struct.S2 = type { i32 }
+
+@s0 = common global %struct.S0 zeroinitializer, align 1
+@s1 = common global %struct.S1 zeroinitializer, align 1
+@s2 = common global %struct.S2 zeroinitializer, align 1
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!33, !34, !35}
+!llvm.ident = !{!36}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 273812) (llvm/trunk 273843)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3)
+!1 = !DIFile(filename: "-", directory: "/usr/local/google/home/majnemer/llvm/src")
+!2 = !{}
+!3 = !{!4, !10, !29}
+!4 = distinct !DIGlobalVariable(name: "s0", scope: !0, file: !5, line: 7, type: !6, isLocal: false, isDefinition: true, variable: %struct.S0* @s0)
+!5 = !DIFile(filename: "<stdin>", directory: "/usr/local/google/home/majnemer/llvm/src")
+!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S0", file: !5, line: 3, size: 24, align: 8, elements: !7)
+!7 = !{!8}
+!8 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !6, file: !5, line: 6, baseType: !9, size: 8, align: 16, offset: 16, flags: DIFlagBitField, extraData: i64 8)
+!9 = !DIBasicType(name: "short", size: 16, align: 16, encoding: DW_ATE_signed)
+!10 = distinct !DIGlobalVariable(name: "s1", scope: !0, file: !5, line: 18, type: !11, isLocal: false, isDefinition: true, variable: %struct.S1* @s1)
+!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S1", file: !5, line: 10, size: 128, align: 8, elements: !12)
+!12 = !{!13, !18, !19, !21, !22, !23, !28}
+!13 = !DIDerivedType(tag: DW_TAG_member, name: "x1", scope: !11, file: !5, line: 11, baseType: !14, size: 16, align: 8)
+!14 = !DICompositeType(tag: DW_TAG_array_type, baseType: !15, size: 16, align: 8, elements: !16)
+!15 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
+!16 = !{!17}
+!17 = !DISubrange(count: 2)
+!18 = !DIDerivedType(tag: DW_TAG_member, name: "x2", scope: !11, file: !5, line: 12, baseType: !15, size: 8, align: 8, offset: 16)
+!19 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !11, file: !5, line: 13, baseType: !20, size: 23, align: 32, offset: 24, flags: DIFlagBitField, extraData: i64 24)
+!20 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!21 = !DIDerivedType(tag: DW_TAG_member, name: "z", scope: !11, file: !5, line: 14, baseType: !20, size: 23, align: 32, offset: 56, flags: DIFlagBitField, extraData: i64 56)
+!22 = !DIDerivedType(tag: DW_TAG_member, name: "w", scope: !11, file: !5, line: 15, baseType: !20, size: 2, align: 32, offset: 79, flags: DIFlagBitField, extraData: i64 56)
+!23 = !DIDerivedType(tag: DW_TAG_member, name: "v", scope: !11, file: !5, line: 16, baseType: !24, size: 24, align: 8, offset: 88)
+!24 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !11, file: !5, line: 16, size: 24, align: 8, elements: !25)
+!25 = !{!26, !27}
+!26 = !DIDerivedType(tag: DW_TAG_member, name: "c", scope: !24, file: !5, line: 16, baseType: !15, size: 8, align: 8)
+!27 = !DIDerivedType(tag: DW_TAG_member, name: "s", scope: !24, file: !5, line: 16, baseType: !9, size: 16, align: 16, offset: 8)
+!28 = !DIDerivedType(tag: DW_TAG_member, name: "u", scope: !11, file: !5, line: 17, baseType: !9, size: 3, align: 16, offset: 112, flags: DIFlagBitField, extraData: i64 112)
+!29 = distinct !DIGlobalVariable(name: "s2", scope: !0, file: !5, line: 24, type: !30, isLocal: false, isDefinition: true, variable: %struct.S2* @s2)
+!30 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S2", file: !5, line: 21, size: 32, align: 8, elements: !31)
+!31 = !{!32}
+!32 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !30, file: !5, line: 23, baseType: !20, size: 1, align: 32, flags: DIFlagBitField, extraData: i64 0)
+!33 = !{i32 2, !"CodeView", i32 1}
+!34 = !{i32 2, !"Debug Info Version", i32 3}
+!35 = !{i32 1, !"PIC Level", i32 2}
+!36 = !{!"clang version 3.9.0 (trunk 273812) (llvm/trunk 273843)"}