[DWARF5][SplitDwarf] Set default state for -fsplit-dwarf-inlining to be false.

[avl]

Summary

This patch is extracted from D71244. The -fsplit-dwarf-inlining option does
not conform to DWARF5 standard. It creates children for Skeleton compilation
unit. We need default behavior to be DWARF5 compatible. Thus, set default
state for -fsplit-dwarf-inlining into "false".

[dblaikie]

We need default behavior to be DWARF5 compatible.

I don't think that's actually a huge issue - gdb certainly didn't seem to have a problem with this extra DWARF (& was the only implementation of Split DWARF For a while) - I don't imagine lldb has any problem with it either (because it's been the default for a while, etc).

But, yeah, seems fair to me.

clang/lib/Driver/ToolChains/Clang.cpp

static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
   //  * what debugger tuning to use
   // This avoids having to monkey around further in cc1 other than to disable
   // codeview if not running in a Windows environment. Perhaps even that
   // decision should be made in the driver as well though.
   llvm::DebuggerKind DebuggerTuning = TC.getDefaultDebuggerTuning();
 
   bool SplitDWARFInlining =
       Args.hasFlag(options::OPT_fsplit_dwarf_inlining,
-                   options::OPT_fno_split_dwarf_inlining, true);
+                   options::OPT_fno_split_dwarf_inlining, false);
 
   Args.ClaimAllArgs(options::OPT_g_Group);
 
   Arg* SplitDWARFArg;
   DwarfFission = getDebugFissionKind(D, Args, SplitDWARFArg);
 
   if (DwarfFission != DwarfFissionKind::None &&
       !checkDebugInfoOption(SplitDWARFArg, Args, D, TC)) {

clang/test/Driver/split-debug.c

 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -gmlt -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-GMLT-WITH-SPLIT < %t %s
 //
 // CHECK-GMLT-WITH-SPLIT: "-debug-info-kind=line-tables-only"
 // CHECK-GMLT-WITH-SPLIT: "-split-dwarf-file"
 // CHECK-GMLT-WITH-SPLIT: "-split-dwarf-output"
 
+// RUN: %clang -target x86_64-unknown-linux-gnu -g -S -### %s 2> %t
+// RUN: FileCheck -check-prefix=CHECK-NOINLINE-WITHOUT-SPLIT < %t %s
+//
 // RUN: %clang -target x86_64-unknown-linux-gnu -g -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-NOINLINE-WITHOUT-SPLIT < %t %s
 //
 // CHECK-NOINLINE-WITHOUT-SPLIT: "-fno-split-dwarf-inlining"
 // CHECK-NOINLINE-WITHOUT-SPLIT: "-debug-info-kind=limited"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gmlt -gsplit-dwarf -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-WITH-GMLT < %t %s
 //
 // CHECK-SPLIT-WITH-GMLT: "-debug-info-kind=limited"
 // CHECK-SPLIT-WITH-GMLT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-WITH-NOINL < %t %s
 //
 // CHECK-SPLIT-WITH-NOINL: "-debug-info-kind=limited"
 // CHECK-SPLIT-WITH-NOINL: "-split-dwarf-output"
 
-// RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -gmlt -S -### %s 2> %t
+// RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -gmlt -fsplit-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-GMLT-OVER-SPLIT < %t %s
 //
 // CHECK-GMLT-OVER-SPLIT: "-debug-info-kind=line-tables-only"
 // CHECK-GMLT-OVER-SPLIT-NOT: "-split-dwarf-file"
 // CHECK-GMLT-OVER-SPLIT-NOT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gmlt -gsplit-dwarf -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-OVER-GMLT < %t %s