[DebugInfo][AIX] Set target debugger-tune default to dbx

[jsji]

Summary

https://reviews.llvm.org/D99400 set clang DefaultDebuggerTuning for AIX
to dbx. However, we still need to update the target default so that llc
and other tools will get the same default debuggertuning, and avoid
passing extra options in LTO.

[dblaikie]

llvm/test/DebugInfo/PowerPC/debugger-tune.ll

4

Maybe "We use the use of DW_FORM_string (rather than DW_FORM_strp) to distinguish debugger tuning"

15–16

Rather than "not" maybe implicit-check-not and an active check for the positive case (otherwise if we used some futuristic alternative string encoding (like DWARFv5 strx encodings if we change to DWARFv5 by default) this test would still pass accidentally)

[jsji]

llvm/test/DebugInfo/PowerPC/debugger-tune.ll

15–16

Good suggestion. Thanks!

[jsji]

Address review comments.

[dblaikie]

Looks good, thanks!

[shchenz]

This will save the option setting for tuning debugger for components involving llc (for example, LTO) as described in the description.
LGTM too. Thanks for doing this.

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

DwarfDebug::DwarfDebug(AsmPrinter *A)
   // Make sure we know our "debugger tuning".  The target option takes
   // precedence; fall back to triple-based defaults.
   if (Asm->TM.Options.DebuggerTuning != DebuggerKind::Default)
     DebuggerTuning = Asm->TM.Options.DebuggerTuning;
   else if (IsDarwin)
     DebuggerTuning = DebuggerKind::LLDB;
   else if (TT.isPS4CPU())
     DebuggerTuning = DebuggerKind::SCE;
+  else if (TT.isOSAIX())
+    DebuggerTuning = DebuggerKind::DBX;
   else
     DebuggerTuning = DebuggerKind::GDB;
 
   if (DwarfInlinedStrings == Default)
     UseInlineStrings = TT.isNVPTX() || tuneForDBX();
   else
     UseInlineStrings = DwarfInlinedStrings == Enable;
 

llvm/test/DebugInfo/PowerPC/debugger-tune.ll

+; Verify target-based defaults for "debugger tuning," and the ability to
+; override defaults.
+; We use the use of DW_FORM_string (rather than DW_FORM_strp) to distinguish the debugger tuning.
+
+; Verify defaults for various targets.
+; RUN: llc -mtriple=powerpc64le-unknown-linux -filetype=obj < %s | llvm-dwarfdump -debug-info --show-form - | FileCheck --check-prefix=GDB %s --implicit-check-not DW_FORM_string
+; TODO: Use -filetype-obj and llvm-dwarfdump when the obj mode is supported.
+; RUN: llc -mtriple=powerpc64-ibm-aix-xcoff < %s | FileCheck --check-prefix=DBX --implicit-check-not DW_FROM_strp %s
+
+; We can override defaults.
+; RUN: llc -mtriple=powerpc64le-unknown-linux -filetype=obj -debugger-tune=dbx < %s | llvm-dwarfdump -debug-info --show-form - | FileCheck --check-prefix=DBX %s --implicit-check-not DW_FROM_strp
+; RUN: llc -mtriple=powerpc64-ibm-aix-xcoff -debugger-tune=gdb < %s | FileCheck --check-prefix=GDB %s --implicit-check-not DW_FORM_string
+
+; GDB: DW_FORM_strp
+; DBX: DW_FORM_string
+
+; Function Attrs: noinline nounwind optnone
+define i32 @main() #0 !dbg !8 {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval, align 4
+  ret i32 0, !dbg !12
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 12.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "1.c", directory: "debug")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 12.0.0"}
+!8 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 1, type: !9, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !DILocation(line: 3, column: 3, scope: !8)

llvm/test/DebugInfo/XCOFF/empty.ll

 
-; RUN: llc -mtriple powerpc-ibm-aix-xcoff < %s | \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc-ibm-aix-xcoff < %s | \
 ; RUN:   FileCheck %s --check-prefix=ASM32
-; RUN: llc -mtriple powerpc64-ibm-aix-xcoff < %s | \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc64-ibm-aix-xcoff < %s | \
 ; RUN:   FileCheck %s --check-prefix=ASM64
 
 source_filename = "1.c"
 target datalayout = "E-m:a-p:32:32-i64:64-n32"
 
 ; Function Attrs: noinline nounwind optnone
 define i32 @main() #0 !dbg !8 {
 entry:

llvm/test/DebugInfo/XCOFF/explicit-section.ll

 
-; RUN: llc -mtriple powerpc-ibm-aix-xcoff < %s | \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc-ibm-aix-xcoff < %s | \
 ; RUN:   FileCheck %s
 
 source_filename = "2.c"
 target datalayout = "E-m:a-p:32:32-i64:64-n32"
 
 ; Function Attrs: noinline nounwind optnone
 define i32 @bar() #0 !dbg !8 {
 entry:

llvm/test/DebugInfo/XCOFF/function-sections.ll

 
-; RUN: llc -mtriple powerpc-ibm-aix-xcoff -function-sections \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc-ibm-aix-xcoff -function-sections \
 ; RUN:   < %s | FileCheck %s
 
 source_filename = "1.c"
 target datalayout = "E-m:a-p:32:32-i64:64-n32"
 
 ; Function Attrs: noinline nounwind optnone
 define i32 @foo() #0 !dbg !8 {
 entry: