Drop non-cfi assembly support from clang.

After this patch clang will ignore -fdwarf2-cfi-asm and -ffno-dwarf2-cfi-asm and
always print assembly that uses cfi directives.

In llvm, MC itself supports cfi since the end of 2010 (support started
in r119972, is reported in the 2.9 release notes).

In binutils the support has been around for much longer. It looks like
support started to be added in May 2003. It is available in 2.15
(31-Aug-2011, 2.14 is from 12-Jun-2003).

llvm-svn: 207602

Author: espindola

clang/include/clang/Driver/Options.td

@@ -441,8 +441,8 @@ def fdiagnostics_show_template_tree : Flag<["-"], "fdiagnostics-show-template-tr
     HelpText<"Print a template comparison tree for differing templates">;
 def fdollars_in_identifiers : Flag<["-"], "fdollars-in-identifiers">, Group<f_Group>,
   HelpText<"Allow '$' in identifiers">, Flags<[CC1Option]>;
-def fdwarf2_cfi_asm : Flag<["-"], "fdwarf2-cfi-asm">, Group<f_Group>;
-def fno_dwarf2_cfi_asm : Flag<["-"], "fno-dwarf2-cfi-asm">, Group<f_Group>,  Flags<[CC1Option]>;
+def fdwarf2_cfi_asm : Flag<["-"], "fdwarf2-cfi-asm">, Group<clang_ignored_f_Group>;
+def fno_dwarf2_cfi_asm : Flag<["-"], "fno-dwarf2-cfi-asm">, Group<clang_ignored_f_Group>;
 def fdwarf_directory_asm : Flag<["-"], "fdwarf-directory-asm">, Group<f_Group>;
 def fno_dwarf_directory_asm : Flag<["-"], "fno-dwarf-directory-asm">, Group<f_Group>, Flags<[CC1Option]>;
 def felide_constructors : Flag<["-"], "felide-constructors">, Group<f_Group>;

clang/include/clang/Frontend/CodeGenOptions.def

@@ -68,7 +68,6 @@ CODEGENOPT(LessPreciseFPMAD  , 1, 0) ///< Enable less precise MAD instructions t
                                      ///< be generated.
 CODEGENOPT(MergeAllConstants , 1, 1) ///< Merge identical constants.
 CODEGENOPT(NoCommon          , 1, 0) ///< Set when -fno-common or C++ is enabled.
-CODEGENOPT(NoDwarf2CFIAsm    , 1, 0) ///< Set when -fno-dwarf2-cfi-asm is enabled.
 CODEGENOPT(NoDwarfDirectoryAsm , 1, 0) ///< Set when -fno-dwarf-directory-asm is
                                        ///< enabled.
 CODEGENOPT(NoExecStack       , 1, 0) ///< Set when -Wa,--noexecstack is enabled.

clang/lib/CodeGen/BackendUtil.cpp

@@ -503,8 +503,6 @@ TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
     TM->setMCRelaxAll(true);
   if (CodeGenOpts.SaveTempLabels)
     TM->setMCSaveTempLabels(true);
-  if (CodeGenOpts.NoDwarf2CFIAsm)
-    TM->setMCUseCFI(false);
   if (!CodeGenOpts.NoDwarfDirectoryAsm)
     TM->setMCUseDwarfDirectory(true);
   if (CodeGenOpts.NoExecStack)

clang/lib/Driver/Tools.cpp

@@ -1733,19 +1733,6 @@ static bool ShouldDisableAutolink(const ArgList &Args,
                        Default);
 }
 
-static bool ShouldDisableCFI(const ArgList &Args,
-                             const ToolChain &TC) {
-  bool Default = true;
-  if (TC.getTriple().isOSDarwin()) {
-    // The native darwin assembler doesn't support cfi directives, so
-    // we disable them if we think the .s file will be passed to it.
-    Default = TC.useIntegratedAs();
-  }
-  return !Args.hasFlag(options::OPT_fdwarf2_cfi_asm,
-                       options::OPT_fno_dwarf2_cfi_asm,
-                       Default);
-}
-
 static bool ShouldDisableDwarfDirectory(const ArgList &Args,
                                         const ToolChain &TC) {
   bool UseDwarfDirectory = Args.hasFlag(options::OPT_fdwarf_directory_asm,
@@ -3138,9 +3125,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-fno-gnu-keywords");
   }
 
-  if (ShouldDisableCFI(Args, getToolChain()))
-    CmdArgs.push_back("-fno-dwarf2-cfi-asm");
-
   if (ShouldDisableDwarfDirectory(Args, getToolChain()))
     CmdArgs.push_back("-fno-dwarf-directory-asm");
 

clang/lib/Frontend/CompilerInvocation.cpp

@@ -399,7 +399,6 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
   Opts.OmitLeafFramePointer = Args.hasArg(OPT_momit_leaf_frame_pointer);
   Opts.SaveTempLabels = Args.hasArg(OPT_msave_temp_labels);
-  Opts.NoDwarf2CFIAsm = Args.hasArg(OPT_fno_dwarf2_cfi_asm);
   Opts.NoDwarfDirectoryAsm = Args.hasArg(OPT_fno_dwarf_directory_asm);
   Opts.SoftFloat = Args.hasArg(OPT_msoft_float);
   Opts.StrictEnums = Args.hasArg(OPT_fstrict_enums);