Make -f[no-]split-dwarf-inlining CC1 default align with driver default (no inlining)

[MaskRay]

Summary

This makes CC1 and driver defaults consistent.
In addition, for more common cases (-g is specified without -gsplit-dwarf), users will not see -fno-split-dwarf-inlining in CC1 options.

Verified that the below is still true:

• clang -g => splitDebugInlining: false in DICompileUnit
• clang -g -gsplit-dwarf => splitDebugInlining: false in DICompileUnit
• clang -g -gsplit-dwarf -fsplit-dwarf-inlining => no splitDebugInlining: false

[dblaikie]

Sounds alright - I guess this helps reduce -cc1 command lines when they contain the more common/default value? (might be worth mentioning that in the commit to explain the motivation for the change)

clang/include/clang/Driver/Options.td

 def fdebug_types_section: Flag <["-"], "fdebug-types-section">, Group<f_Group>,
   HelpText<"Place debug types in their own section (ELF Only)">;
 def fno_debug_types_section: Flag<["-"], "fno-debug-types-section">, Group<f_Group>;
 defm debug_ranges_base_address : BoolFOption<"debug-ranges-base-address",
   CodeGenOpts<"DebugRangesBaseAddress">, DefaultFalse,
   PosFlag<SetTrue, [CC1Option], "Use DWARF base address selection entries in .debug_ranges">,
   NegFlag<SetFalse>>;
 defm split_dwarf_inlining : BoolFOption<"split-dwarf-inlining",
-  CodeGenOpts<"SplitDwarfInlining">, DefaultTrue,
-  NegFlag<SetFalse, [CC1Option]>,
-  PosFlag<SetTrue, [], "Provide minimal debug info in the object/executable"
+  CodeGenOpts<"SplitDwarfInlining">, DefaultFalse,
+  NegFlag<SetFalse, []>,
+  PosFlag<SetTrue, [CC1Option], "Provide minimal debug info in the object/executable"
           " to facilitate online symbolication/stack traces in the absence of"
           " .dwo/.dwp files when using Split DWARF">>;
 def fdebug_default_version: Joined<["-"], "fdebug-default-version=">, Group<f_Group>,
   HelpText<"Default DWARF version to use, if a -g option caused DWARF debug info to be produced">;
 def fdebug_prefix_map_EQ
   : Joined<["-"], "fdebug-prefix-map=">, Group<f_Group>,
     Flags<[CC1Option,CC1AsOption]>,
     HelpText<"remap file source paths in debug info">;

clang/lib/Driver/ToolChains/Clang.cpp

if (checkDebugInfoOption(A, Args, D, TC)) {
       if (DebugInfoKind != codegenoptions::DebugLineTablesOnly &&
           DebugInfoKind != codegenoptions::DebugDirectivesOnly) {
         DebugInfoKind = codegenoptions::LimitedDebugInfo;
         CmdArgs.push_back("-dwarf-ext-refs");
         CmdArgs.push_back("-fmodule-format=obj");
       }
     }
 
-  if (T.isOSBinFormatELF() && !SplitDWARFInlining)
-    CmdArgs.push_back("-fno-split-dwarf-inlining");
+  if (T.isOSBinFormatELF() && SplitDWARFInlining)
+    CmdArgs.push_back("-fsplit-dwarf-inlining");
 
   // After we've dealt with all combinations of things that could
   // make DebugInfoKind be other than None or DebugLineTablesOnly,
   // figure out if we need to "upgrade" it to standalone debug info.
   // We parse these two '-f' options whether or not they will be used,
   // to claim them even if you wrote "-fstandalone-debug -gline-tables-only"
   bool NeedFullDebug = Args.hasFlag(
       options::OPT_fstandalone_debug, options::OPT_fno_standalone_debug,

clang/test/CodeGen/split-debug-inlining.c

-// RUN: %clang_cc1 -debug-info-kind=limited -fno-split-dwarf-inlining -S -emit-llvm -o - %s | FileCheck %s
-// RUN: %clang_cc1 -debug-info-kind=limited -S -emit-llvm -o - %s | FileCheck --check-prefix=ABSENT %s
+// RUN: %clang_cc1 -debug-info-kind=limited -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -debug-info-kind=limited -fsplit-dwarf-inlining -S -emit-llvm -o - %s | FileCheck --check-prefix=ABSENT %s
 void f(void) {}
 // Verify that disabling split debug inlining info is propagated to the debug
 // info metadata.
 // CHECK: !DICompileUnit({{.*}}, splitDebugInlining: false
 // ABSENT-NOT: splitDebugInlining

clang/test/Driver/split-debug.c

 /// Test -gsplit-dwarf and -gsplit-dwarf={split,single}.
 
 /// Interaction with -g (-g2).
 // RUN: %clang -### -c -target x86_64 -g -gsplit-dwarf %s 2>&1 | FileCheck %s --check-prefixes=NOINLINE,SPLIT
 // RUN: %clang -### -c -target x86_64 -gsplit-dwarf -g %s 2>&1 | FileCheck %s --check-prefixes=NOINLINE,SPLIT
 // RUN: %clang -### -c -target x86_64 -g2 -gsplit-dwarf %s 2>&1 | FileCheck %s --check-prefixes=NOINLINE,SPLIT
 /// -gsplit-dwarf=split is equivalent to -gsplit-dwarf.
 // RUN: %clang -### -c -target x86_64 -gsplit-dwarf=split -g %s 2>&1 | FileCheck %s --check-prefixes=NOINLINE,SPLIT
 
-// INLINE-NOT: "-fno-split-dwarf-inlining"
-// NOINLINE:   "-fno-split-dwarf-inlining"
+// INLINE:     "-fsplit-dwarf-inlining"
+// NOINLINE-NOT: "-fsplit-dwarf-inlining"
 // SPLIT:      "-debug-info-kind=limited"
 // SPLIT-SAME: "-ggnu-pubnames"
 // SPLIT-SAME: "-split-dwarf-file" "split-debug.dwo" "-split-dwarf-output" "split-debug.dwo"
 
 // RUN: %clang -### -c -target wasm32 -gsplit-dwarf -g %s 2>&1 | FileCheck %s --check-prefix=SPLIT
 // RUN: %clang -### -c -target amdgcn-amd-amdhsa -gsplit-dwarf -g %s 2>&1 | FileCheck %s --check-prefix=SPLIT
 
 /// -gsplit-dwarf is a no-op on a non-ELF platform.