[clang][Driver] Add -gdwarf-6 option (#162454)

Now that we slowly started adding support for upcoming DWARFv6
attributes add `-gdwarf-6` as a supported flag.

Author: Michael137

clang/include/clang/Driver/Options.td

@@ -4715,6 +4715,10 @@ def gdwarf_4 : Flag<["-"], "gdwarf-4">, Group<g_Group>,
   HelpText<"Generate source-level debug information with dwarf version 4">;
 def gdwarf_5 : Flag<["-"], "gdwarf-5">, Group<g_Group>,
   HelpText<"Generate source-level debug information with dwarf version 5">;
+def gdwarf_6
+    : Flag<["-"], "gdwarf-6">,
+      Group<g_Group>,
+      HelpText<"Generate source-level debug information with dwarf version 6">;
 }
 def gdwarf64 : Flag<["-"], "gdwarf64">, Group<g_Group>,
   Visibility<[ClangOption, CC1Option, CC1AsOption]>,

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -2231,7 +2231,7 @@ static unsigned ParseDebugDefaultVersion(const ToolChain &TC,
     return 0;
 
   unsigned Value = 0;
-  if (StringRef(A->getValue()).getAsInteger(10, Value) || Value > 5 ||
+  if (StringRef(A->getValue()).getAsInteger(10, Value) || Value > 6 ||
       Value < 2)
     TC.getDriver().Diag(diag::err_drv_invalid_int_value)
         << A->getAsString(Args) << A->getValue();
@@ -2244,13 +2244,14 @@ unsigned tools::DwarfVersionNum(StringRef ArgValue) {
       .Case("-gdwarf-3", 3)
       .Case("-gdwarf-4", 4)
       .Case("-gdwarf-5", 5)
+      .Case("-gdwarf-6", 6)
       .Default(0);
 }
 
 const Arg *tools::getDwarfNArg(const ArgList &Args) {
   return Args.getLastArg(options::OPT_gdwarf_2, options::OPT_gdwarf_3,
                          options::OPT_gdwarf_4, options::OPT_gdwarf_5,
-                         options::OPT_gdwarf);
+                         options::OPT_gdwarf_6, options::OPT_gdwarf);
 }
 
 unsigned tools::getDwarfVersion(const ToolChain &TC,

clang/test/CodeGen/dwarf-version.c

@@ -2,6 +2,7 @@
 // RUN: %clang -target x86_64-linux-gnu -gdwarf-3 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER3
 // RUN: %clang -target x86_64-linux-gnu -gdwarf-4 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER4
 // RUN: %clang -target x86_64-linux-gnu -gdwarf-5 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER5
+// RUN: %clang -target x86_64-linux-gnu -gdwarf-6 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER6
 // RUN: %clang -target x86_64-linux-gnu -g -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER5
 // RUN: %clang -target x86_64-linux-gnu -gdwarf -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER5
 // RUN: %clang --target=i386-pc-solaris -g -S -emit-llvm -o - %s | FileCheck %s --check-prefix=VER5
@@ -61,6 +62,7 @@ int main (void) {
 // VER3: !{i32 7, !"Dwarf Version", i32 3}
 // VER4: !{i32 7, !"Dwarf Version", i32 4}
 // VER5: !{i32 7, !"Dwarf Version", i32 5}
+// VER6: !{i32 7, !"Dwarf Version", i32 6}
 // UNSUPPORTED-VER5: error: unsupported option '-gdwarf-5'
 
 // NODWARF-NOT: !"Dwarf Version"