Add support for -Wa,--noexecstack when building from a non-assembly file. For

an assembly file it worked correctly, while for a .c file it would given an
error about how --noexecstack is not a supported argument to -Wa.

llvm-svn: 133489

Author: nlewycky

clang/include/clang/Driver/CC1Options.td

@@ -157,6 +157,8 @@ def mfloat_abi : Separate<"-mfloat-abi">,
   HelpText<"The float ABI to use">;
 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 mno_zero_initialized_in_bss : Flag<"-mno-zero-initialized-in-bss">,
   HelpText<"Do not put zero initialized data in the BSS">;
 def momit_leaf_frame_pointer : Flag<"-momit-leaf-frame-pointer">,

clang/include/clang/Frontend/CodeGenOptions.h

@@ -70,6 +70,7 @@ class CodeGenOptions {
   unsigned MergeAllConstants : 1; /// Merge identical constants.
   unsigned NoCommon          : 1; /// Set when -fno-common or C++ is enabled.
   unsigned NoDwarf2CFIAsm    : 1; /// Set when -fno-dwarf2-cfi-asm is enabled.
+  unsigned NoExecStack       : 1; /// Set when -Wa,--noexecstack is enabled.
   unsigned NoImplicitFloat   : 1; /// Set when -mno-implicit-float is enabled.
   unsigned NoInfsFPMath      : 1; /// Assume FP arguments, results not +-Inf.
   unsigned NoNaNsFPMath      : 1; /// Assume FP arguments, results not NaN.

clang/lib/CodeGen/BackendUtil.cpp

@@ -275,6 +275,8 @@ bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
     TM->setMCSaveTempLabels(true);
   if (CodeGenOpts.NoDwarf2CFIAsm)
     TM->setMCUseCFI(false);
+  if (CodeGenOpts.NoExecStack)
+    TM->setMCNoExecStack(true);
 
   // Create the code generator passes.
   PassManager *PM = getCodeGenPasses();

clang/lib/Driver/Tools.cpp

@@ -1051,6 +1051,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
         } else if (Value == "--fatal-warnings") {
           CmdArgs.push_back("-mllvm");
           CmdArgs.push_back("-fatal-assembler-warnings");
+        } else if (Value == "--noexecstack") {
+          CmdArgs.push_back("-mnoexecstack");
         } else {
           D.Diag(clang::diag::err_drv_unsupported_option_argument)
             << A->getOption().getName() << Value;

clang/lib/Frontend/CompilerInvocation.cpp

@@ -201,6 +201,8 @@ static void CodeGenOptsToArgs(const CodeGenOptions &Opts,
     Res.push_back("-mregparm");
     Res.push_back(llvm::utostr(Opts.NumRegisterParameters));
   }
+  if (Opts.NoExecStack)
+    Res.push_back("-mnoexecstack");
   if (Opts.RelaxAll)
     Res.push_back("-mrelax-all");
   if (Opts.SaveTempLabels)
@@ -982,6 +984,7 @@ static void ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.NoZeroInitializedInBSS = Args.hasArg(OPT_mno_zero_initialized_in_bss);
   Opts.BackendOptions = Args.getAllArgValues(OPT_backend_option);
   Opts.NumRegisterParameters = Args.getLastArgIntValue(OPT_mregparm, 0, Diags);
+  Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
   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/noexecstack.c

@@ -0,0 +1 @@
+// RUN: clang -### %s -c -o tmp.o -Wa,--noexecstack | grep "-mnoexecstack"