[SystemZ] Add -mbackchain option.

This option, like the corresponding gcc option, is SystemZ-specific and
enables storing frame backchain links, as specified in the ABI.

Differential Revision: http://reviews.llvm.org/D19891

llvm-svn: 268575

3 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 50ea7f7cc33..8a26db2116d 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1714,6 +1714,8 @@ void CodeGenModule::ConstructAttributeList(
 
     if (CodeGenOpts.StackRealignment)
       FuncAttrs.addAttribute("stackrealign");
+    if (CodeGenOpts.Backchain)
+      FuncAttrs.addAttribute("backchain");
 
     // Add target-cpu and target-features attributes to functions. If
     // we have a decl for the function and it has a target attribute then
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 1cc1369f330..c688763e69d 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1655,6 +1655,12 @@ void Clang::AddSparcTargetArgs(const ArgList &Args,
   }
 }
 
+void Clang::AddSystemZTargetArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  if (Args.hasFlag(options::OPT_mbackchain, options::OPT_mno_backchain, false))
+    CmdArgs.push_back("-mbackchain");
+}
+
 static const char *getSystemZTargetCPU(const ArgList &Args) {
   if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
     return A->getValue();
@@ -4241,6 +4247,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     AddSparcTargetArgs(Args, CmdArgs);
     break;
 
+  case llvm::Triple::systemz:
+    AddSystemZTargetArgs(Args, CmdArgs);
+    break;
+
   case llvm::Triple::x86:
   case llvm::Triple::x86_64:
     AddX86TargetArgs(Args, CmdArgs);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 2091ec4af32..0b154b6743c 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -782,6 +782,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.CudaGpuBinaryFileNames =
       Args.getAllArgValues(OPT_fcuda_include_gpubinary);
 
+  Opts.Backchain = Args.hasArg(OPT_mbackchain);
+
   return Success;
 }