[DebugInfo] Introduce DW_OP_LLVM_convert
Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.
The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.
For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.
Differential Revision: https://reviews.llvm.org/D56587
llvm-svn: 356442
diff --git a/llvm/test/DebugInfo/Generic/convert-linked.ll b/llvm/test/DebugInfo/Generic/convert-linked.ll
new file mode 100644
index 0000000..8d277d8
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/convert-linked.ll
@@ -0,0 +1,72 @@
+; RUN: llc -filetype=obj -O0 < %s | llvm-dwarfdump - | FileCheck %s
+
+; CHECK: DW_TAG_compile_unit
+; CHECK: [[CU0BT0:0x[0-9a-f]+]]: DW_TAG_base_type
+; CHECK-NEXT: DW_ATE_signed_8
+; CHECK: [[CU0BT1:0x[0-9a-f]+]]: DW_TAG_base_type
+; CHECK-NEXT: DW_ATE_signed_32
+; CHECK: DW_TAG_variable
+; CHECK: DW_OP_convert ([[CU0BT0]]) "DW_ATE_signed_8", DW_OP_convert ([[CU0BT1]]) "DW_ATE_signed_32"
+
+; CHECK: DW_TAG_compile_unit
+; CHECK: [[CU1BT0:0x[0-9a-f]+]]: DW_TAG_base_type
+; CHECK-NEXT: DW_ATE_signed_8
+; CHECK: [[CU1BT1:0x[0-9a-f]+]]: DW_TAG_base_type
+; CHECK-NEXT: DW_ATE_signed_16
+; CHECK: DW_TAG_variable
+; CHECK: DW_OP_convert ([[CU1BT0]]) "DW_ATE_signed_8", DW_OP_convert ([[CU1BT1]]) "DW_ATE_signed_16"
+
+; ModuleID = 'llvm-link'
+source_filename = "llvm-link"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define dso_local signext i8 @foo(i8 signext %x) !dbg !9 {
+entry:
+ call void @llvm.dbg.value(metadata i8 %x, metadata !13, metadata !DIExpression()), !dbg !14
+ call void @llvm.dbg.value(metadata i8 %x, metadata !15, metadata !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value)), !dbg !17
+ ret i8 %x, !dbg !18
+}
+
+define dso_local signext i8 @bar(i8 signext %x) !dbg !19 {
+entry:
+ call void @llvm.dbg.value(metadata i8 %x, metadata !20, metadata !DIExpression()), !dbg !21
+ call void @llvm.dbg.value(metadata i8 %x, metadata !22, metadata !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed, DW_OP_LLVM_convert, 16, DW_ATE_signed, DW_OP_stack_value)), !dbg !24
+ ret i8 %x, !dbg !25
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+attributes #1 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!0, !3}
+!llvm.ident = !{!5, !5}
+!llvm.module.flags = !{!6, !7, !8}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 9.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "dbg-foo.c", directory: "/tmp", checksumkind: CSK_MD5, checksum: "b35f80a032deb2a30bc187d564b5a775")
+!2 = !{}
+!3 = distinct !DICompileUnit(language: DW_LANG_C99, file: !4, producer: "clang version 9.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!4 = !DIFile(filename: "dbg-bar.c", directory: "/tmp", checksumkind: CSK_MD5, checksum: "9836bb594260d883960455e7d8bc51ea")
+!5 = !{!"clang version 9.0.0 "}
+!6 = !{i32 2, !"Dwarf Version", i32 5}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = !{i32 1, !"wchar_size", i32 4}
+!9 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 7, type: !10, scopeLine: 8, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!10 = !DISubroutineType(types: !11)
+!11 = !{!12, !12}
+!12 = !DIBasicType(name: "signed char", size: 8, encoding: DW_ATE_signed_char)
+!13 = !DILocalVariable(name: "x", arg: 1, scope: !9, file: !1, line: 7, type: !12)
+!14 = !DILocation(line: 7, column: 29, scope: !9)
+!15 = !DILocalVariable(name: "y", scope: !9, file: !1, line: 9, type: !16)
+!16 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!17 = !DILocation(line: 9, column: 14, scope: !9)
+!18 = !DILocation(line: 10, column: 3, scope: !9)
+!19 = distinct !DISubprogram(name: "bar", scope: !4, file: !4, line: 1, type: !10, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !3, retainedNodes: !2)
+!20 = !DILocalVariable(name: "x", arg: 1, scope: !19, file: !4, line: 1, type: !12)
+!21 = !DILocation(line: 1, column: 29, scope: !19)
+!22 = !DILocalVariable(name: "z", scope: !19, file: !4, line: 3, type: !23)
+!23 = !DIBasicType(name: "short", size: 16, encoding: DW_ATE_signed)
+!24 = !DILocation(line: 3, column: 16, scope: !19)
+!25 = !DILocation(line: 4, column: 3, scope: !19)