[llvm] [DebugInfo] Add DW_OP_LLVM_extract_bits (PR #93990)

[Adrian Prantl via llvm-commits]

================
@@ -0,0 +1,99 @@
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu %s -o %t -filetype=obj
+; RUN: llvm-dwarfdump --debug-info %t | FileCheck %s
+
+%struct.struct_t = type { i8 }
+
+ at g = dso_local global %struct.struct_t zeroinitializer, align 1, !dbg !0
+
+; CHECK-LABEL: DW_TAG_subprogram
+; CHECK: DW_AT_name ("test1")
+; CHECK: DW_TAG_variable
+; CHECK: DW_AT_location (DW_OP_fbreg -1, DW_OP_deref, DW_OP_constu 0x3d, DW_OP_shl, DW_OP_constu 0x3d, DW_OP_shr, DW_OP_stack_value)
+; CHECK: DW_AT_name ("x")
+; CHECK: DW_TAG_variable
+; CHECK: DW_AT_location (DW_OP_fbreg -1, DW_OP_deref, DW_OP_constu 0x39, DW_OP_shl, DW_OP_constu 0x3c, DW_OP_shra, DW_OP_stack_value)
+; CHECK: DW_AT_name ("y")
+
+define i32 @test1() !dbg !13 {
+entry:
+  %0 = alloca %struct.struct_t, align 1
+  tail call void @llvm.dbg.declare(metadata ptr %0, metadata !17, metadata !DIExpression(DW_OP_LLVM_extract_bits, 0, 3, DW_ATE_unsigned)), !dbg !18
+  tail call void @llvm.dbg.declare(metadata ptr %0, metadata !19, metadata !DIExpression(DW_OP_LLVM_extract_bits, 3, 4, DW_ATE_signed)), !dbg !21
+  ret i32 0, !dbg !22
+}
+
+; CHECK-LABEL: DW_TAG_subprogram
+; CHECK: DW_AT_name ("test2")
+; CHECK: DW_TAG_variable
+; CHECK: DW_AT_location (DW_OP_breg0 RAX+0, DW_OP_constu 0xff, DW_OP_and, DW_OP_constu 0x3d, DW_OP_shl, DW_OP_constu 0x3d, DW_OP_shr, DW_OP_stack_value)
+; CHECK: DW_AT_name ("x")
+; CHECK: DW_TAG_variable
+; CHECK: DW_AT_location (DW_OP_breg0 RAX+0, DW_OP_constu 0xff, DW_OP_and, DW_OP_constu 0x39, DW_OP_shl, DW_OP_constu 0x3c, DW_OP_shra, DW_OP_stack_value)
+; CHECK: DW_AT_name ("y")
+
+define i8 @test2() !dbg !23 {
+entry:
+  %0 = load i8, ptr @g, align 1
+  tail call void @llvm.dbg.value(metadata i8 %0, metadata !24, metadata !DIExpression(DW_OP_LLVM_extract_bits, 0, 3, DW_ATE_unsigned)), !dbg !25
+  tail call void @llvm.dbg.value(metadata i8 %0, metadata !26, metadata !DIExpression(DW_OP_LLVM_extract_bits, 3, 4, DW_ATE_signed)), !dbg !27
+  ret i8 %0, !dbg !28
+}
+
+; CHECK-LABEL: DW_TAG_subprogram
+; CHECK: DW_AT_name ("test3")
+; CHECK: DW_TAG_variable
+; CHECK: DW_AT_location (DW_OP_breg0 RAX+0, DW_OP_constu 0x3f, DW_OP_shr, DW_OP_stack_value)
+; CHECK: DW_AT_name ("x")
+; CHECK: DW_TAG_variable
+; CHECK: DW_AT_location (DW_OP_breg0 RAX+0, DW_OP_constu 0x3f, DW_OP_shra, DW_OP_stack_value)
+; CHECK: DW_AT_name ("y")
+
+define i64 @test3(ptr %p) !dbg !29 {
+entry:
+  %0 = load i64, ptr %p, align 8
+  tail call void @llvm.dbg.value(metadata i64 %0, metadata !33, metadata !DIExpression(DW_OP_LLVM_extract_bits, 63, 1, DW_ATE_unsigned)), !dbg !30
+  tail call void @llvm.dbg.value(metadata i64 %0, metadata !34, metadata !DIExpression(DW_OP_LLVM_extract_bits, 63, 1, DW_ATE_signed)), !dbg !31
+  ret i64 %0, !dbg !32
+}
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!11, !12}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 6, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "DW_OP_bit_piece.cpp", directory: "./")
+!4 = !{!0}
+!5 = !DIDerivedType(tag: DW_TAG_typedef, name: "struct_t", file: !3, line: 4, baseType: !6)
+!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, file: !3, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTS8struct_t")
+!7 = !{!8, !10}
+!8 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !6, file: !3, line: 2, baseType: !9, size: 3, flags: DIFlagBitField, extraData: i64 0)
+!9 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!10 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !6, file: !3, line: 3, baseType: !9, size: 4, offset: 3, flags: DIFlagBitField, extraData: i64 0)
+!11 = !{i32 7, !"Dwarf Version", i32 5}
+!12 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = distinct !DISubprogram(name: "test1", linkageName: "test1", scope: !3, file: !3, line: 8, type: !14, scopeLine: 8, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !16)
+!14 = !DISubroutineType(types: !15)
+!15 = !{!9}
+!16 = !{}
+!17 = !DILocalVariable(name: "x", scope: !13, file: !3, line: 9, type: !9)
+!18 = !DILocation(line: 9, column: 9, scope: !13)
+!19 = !DILocalVariable(name: "y", scope: !13, file: !3, line: 9, type: !20)
+!20 = !DIBasicType(name: "signed int", size: 32, encoding: DW_ATE_signed)
+!21 = !DILocation(line: 9, column: 12, scope: !13)
----------------
adrian-prantl wrote:

You an probably collapse most of the DILocations to a single line 0 one to make the example more focussed.

https://github.com/llvm/llvm-project/pull/93990