Plumb through the -fsplit-stack option using the existing backend

support.

Caveat: Other than the existing segmented stacks support, no
claims are made of this working.

llvm-svn: 178744

clang/include/clang/Driver/CC1Options.td

@@ -184,6 +184,8 @@ def mlimit_float_precision : Separate<["-"], "mlimit-float-precision">,
   HelpText<"Limit float precision to the given value">;
 def mno_exec_stack : Flag<["-"], "mnoexecstack">,
   HelpText<"Mark the file as not needing an executable stack">;
+def split_stacks : Flag<["-"], "split-stacks">,
+  HelpText<"Try to use a split stack if possible.">;
 def mno_zero_initialized_in_bss : Flag<["-"], "mno-zero-initialized-in-bss">,
   HelpText<"Do not put zero initialized data in the BSS">;
 def backend_option : Separate<["-"], "backend-option">,

clang/include/clang/Driver/Options.td

@@ -675,6 +675,7 @@ def fshow_source_location : Flag<["-"], "fshow-source-location">, Group<f_Group>
 def fspell_checking : Flag<["-"], "fspell-checking">, Group<f_Group>;
 def fsigned_bitfields : Flag<["-"], "fsigned-bitfields">, Group<f_Group>;
 def fsigned_char : Flag<["-"], "fsigned-char">, Group<f_Group>;
+def fsplit_stack : Flag<["-"], "fsplit-stack">, Group<f_Group>;
 def fstack_protector_all : Flag<["-"], "fstack-protector-all">, Group<f_Group>;
 def fstack_protector : Flag<["-"], "fstack-protector">, Group<f_Group>;
 def fstrict_aliasing : Flag<["-"], "fstrict-aliasing">, Group<f_Group>;

clang/include/clang/Frontend/CodeGenOptions.def

@@ -70,6 +70,7 @@ CODEGENOPT(NoDwarf2CFIAsm    , 1, 0) ///< Set when -fno-dwarf2-cfi-asm is enable
 CODEGENOPT(NoDwarfDirectoryAsm , 1, 0) ///< Set when -fno-dwarf-directory-asm is
                                        ///< enabled.
 CODEGENOPT(NoExecStack       , 1, 0) ///< Set when -Wa,--noexecstack is enabled.
+CODEGENOPT(EnableSegmentedStacks , 1, 0) ///< Set when -fsplit-stack is enabled.
 CODEGENOPT(NoGlobalMerge     , 1, 0) ///< Set when -mno-global-merge is enabled.
 CODEGENOPT(NoImplicitFloat   , 1, 0) ///< Set when -mno-implicit-float is enabled.
 CODEGENOPT(NoInfsFPMath      , 1, 0) ///< Assume FP arguments, results not +-Inf.

clang/lib/CodeGen/BackendUtil.cpp

@@ -457,6 +457,7 @@ TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
   Options.TrapFuncName = CodeGenOpts.TrapFuncName;
   Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
   Options.SSPBufferSize = CodeGenOpts.SSPBufferSize;
+  Options.EnableSegmentedStacks = CodeGenOpts.EnableSegmentedStacks;
 
   TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
                                                      FeaturesStr, Options,

clang/lib/Driver/Tools.cpp

@@ -2112,6 +2112,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                     options::OPT_fno_optimize_sibling_calls))
     CmdArgs.push_back("-mdisable-tail-calls");
 
+  // Handle segmented stacks.
+  if (Args.hasArg(options::OPT_fsplit_stack))
+    CmdArgs.push_back("-split-stacks");
+  
   // Handle various floating point optimization flags, mapping them to the
   // appropriate LLVM code generation flags. The pattern for all of these is to
   // default off the codegen optimizations, and if any flag enables them and no

clang/lib/Frontend/CompilerInvocation.cpp

@@ -358,6 +358,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.NumRegisterParameters = Args.getLastArgIntValue(OPT_mregparm, 0, Diags);
   Opts.NoGlobalMerge = Args.hasArg(OPT_mno_global_merge);
   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
+  Opts.EnableSegmentedStacks = Args.hasArg(OPT_split_stacks);
   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
   Opts.OmitLeafFramePointer = Args.hasArg(OPT_momit_leaf_frame_pointer);
   Opts.SaveTempLabels = Args.hasArg(OPT_msave_temp_labels);

clang/test/Driver/clang_f_opts.c

@@ -1,6 +1,7 @@
-// RUN: %clang -### -S -fasm -fblocks -fbuiltin -fno-math-errno -fcommon -fpascal-strings -fno-blocks -fno-builtin -fmath-errno -fno-common -fno-pascal-strings -fblocks -fbuiltin -fmath-errno -fcommon -fpascal-strings %s 2>&1 | FileCheck -check-prefix=CHECK-OPTIONS1 %s
+// RUN: %clang -### -S -fasm -fblocks -fbuiltin -fno-math-errno -fcommon -fpascal-strings -fno-blocks -fno-builtin -fmath-errno -fno-common -fno-pascal-strings -fblocks -fbuiltin -fmath-errno -fcommon -fpascal-strings -fsplit-stack %s 2>&1 | FileCheck -check-prefix=CHECK-OPTIONS1 %s
 // RUN: %clang -### -S -fasm -fblocks -fbuiltin -fno-math-errno -fcommon -fpascal-strings -fno-asm -fno-blocks -fno-builtin -fmath-errno -fno-common -fno-pascal-strings -fno-show-source-location -fshort-enums -fshort-wchar %s 2>&1 | FileCheck -check-prefix=CHECK-OPTIONS2 %s
 
+// CHECK-OPTIONS1: -split-stacks
 // CHECK-OPTIONS1: -fgnu-keywords
 // CHECK-OPTIONS1: -fblocks
 // CHECK-OPTIONS1: -fpascal-strings