[clang] [SystemZ] Add -mbackchain option.

[• koriakin]

Summary

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

Depends on D19889.

[uweigand]

LGTM.

cfe/trunk/include/clang/Driver/Options.td

 
 def fzvector : Flag<["-"], "fzvector">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Enable System z vector language extension">;
 def fno_zvector : Flag<["-"], "fno-zvector">, Group<f_Group>,
   Flags<[CC1Option]>;
 def mzvector : Flag<["-"], "mzvector">, Alias<fzvector>;
 def mno_zvector : Flag<["-"], "mno-zvector">, Alias<fno_zvector>;
 
+def mbackchain : Flag<["-"], "mbackchain">, Group<m_Group>, Flags<[DriverOption,CC1Option]>,
+  HelpText<"Link stack frames through backchain on System Z">;
+def mno_backchain : Flag<["-"], "mno-backchain">, Group<m_Group>, Flags<[DriverOption,CC1Option]>;
+
 def mno_warn_nonportable_cfstrings : Flag<["-"], "mno-warn-nonportable-cfstrings">, Group<m_Group>;
 def mno_omit_leaf_frame_pointer : Flag<["-"], "mno-omit-leaf-frame-pointer">, Group<m_Group>;
 def momit_leaf_frame_pointer : Flag<["-"], "momit-leaf-frame-pointer">, Group<m_Group>,
   HelpText<"Omit frame pointer setup for leaf functions">, Flags<[CC1Option]>;
 def moslib_EQ : Joined<["-"], "moslib=">, Group<m_Group>;
 def mpascal_strings : Flag<["-"], "mpascal-strings">, Alias<fpascal_strings>;
 def mred_zone : Flag<["-"], "mred-zone">, Group<m_Group>;
 def mregparm_EQ : Joined<["-"], "mregparm=">, Group<m_Group>;

cfe/trunk/include/clang/Frontend/CodeGenOptions.def

 #endif
 
 CODEGENOPT(DisableIntegratedAS, 1, 0) ///< -no-integrated-as
 CODEGENOPT(CompressDebugSections, 1, 0) ///< -Wa,-compress-debug-sections
 CODEGENOPT(AsmVerbose        , 1, 0) ///< -dA, -fverbose-asm.
 CODEGENOPT(AssumeSaneOperatorNew , 1, 1) ///< implicit __attribute__((malloc)) operator new
 CODEGENOPT(Autolink          , 1, 1) ///< -fno-autolink
 CODEGENOPT(ObjCAutoRefCountExceptions , 1, 0) ///< Whether ARC should be EH-safe.
+CODEGENOPT(Backchain         , 1, 0) ///< -mbackchain
 CODEGENOPT(CoverageExtraChecksum, 1, 0) ///< Whether we need a second checksum for functions in GCNO files.
 CODEGENOPT(CoverageNoFunctionNamesInData, 1, 0) ///< Do not include function names in GCDA files.
 CODEGENOPT(CoverageExitBlockBeforeBody, 1, 0) ///< Whether to emit the exit block before the body blocks in GCNO files.
 CODEGENOPT(CXAAtExit         , 1, 1) ///< Use __cxa_atexit for calling destructors.
 CODEGENOPT(CXXCtorDtorAliases, 1, 0) ///< Emit complete ctors/dtors as linker
                                      ///< aliases to base ctors when possible.
 CODEGENOPT(DataSections      , 1, 0) ///< Set when -fdata-sections is enabled.
 CODEGENOPT(UniqueSectionNames, 1, 1) ///< Set for -funique-section-names.

cfe/trunk/lib/CodeGen/CGCall.cpp

FuncAttrs.addAttribute("unsafe-fp-math",
                            llvm::toStringRef(CodeGenOpts.UnsafeFPMath));
     FuncAttrs.addAttribute("use-soft-float",
                            llvm::toStringRef(CodeGenOpts.SoftFloat));
     FuncAttrs.addAttribute("stack-protector-buffer-size",
                            llvm::utostr(CodeGenOpts.SSPBufferSize));
 
     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
     // parse that and add it to the feature set.
     StringRef TargetCPU = getTarget().getTargetOpts().CPU;
     const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl);
     if (FD && FD->hasAttr<TargetAttr>()) {
       llvm::StringMap<bool> FeatureMap;

cfe/trunk/lib/Driver/Tools.cpp

void Clang::AddSparcTargetArgs(const ArgList &Args,
   // currently does not support Sparc soft-float, at all, display an
   // error if it's requested.
   if (SoftFloatABI) {
     D.Diag(diag::err_drv_unsupported_opt_for_target) << "-msoft-float"
                                                      << Triple;
   }
 }
 
+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();
   return "z10";
 }
 
 static void getSystemZTargetFeatures(const ArgList &Args,
                                      std::vector<const char *> &Features) {
case llvm::Triple::ppc64le:
     break;
 
   case llvm::Triple::sparc:
   case llvm::Triple::sparcel:
   case llvm::Triple::sparcv9:
     AddSparcTargetArgs(Args, CmdArgs);
     break;
 
+  case llvm::Triple::systemz:
+    AddSystemZTargetArgs(Args, CmdArgs);
+    break;
+
   case llvm::Triple::x86:
   case llvm::Triple::x86_64:
     AddX86TargetArgs(Args, CmdArgs);
     break;
 
   case llvm::Triple::lanai:
     AddLanaiTargetArgs(Args, CmdArgs);
     break;

cfe/trunk/lib/Frontend/CompilerInvocation.cpp

parseSanitizerKinds("-fsanitize-recover=",
                       Opts.SanitizeRecover);
   parseSanitizerKinds("-fsanitize-trap=",
                       Args.getAllArgValues(OPT_fsanitize_trap_EQ), Diags,
                       Opts.SanitizeTrap);
 
   Opts.CudaGpuBinaryFileNames =
       Args.getAllArgValues(OPT_fcuda_include_gpubinary);
 
+  Opts.Backchain = Args.hasArg(OPT_mbackchain);
+
   return Success;
 }
 
 static void ParseDependencyOutputArgs(DependencyOutputOptions &Opts,
                                       ArgList &Args) {
   using namespace options;
   Opts.OutputFile = Args.getLastArgValue(OPT_dependency_file);
   Opts.Targets = Args.getAllArgValues(OPT_MT);

cfe/trunk/test/CodeGen/mbackchain-2.c

+// RUN: %clang -mbackchain --target=s390x-linux -S -emit-llvm -o - %s | FileCheck %s
+
+// CHECK: define void @foo() [[NUW:#[0-9]+]]
+void foo(void) {
+}
+
+// CHECK: attributes [[NUW]] = { {{.*}} "backchain" {{.*}} }

cfe/trunk/test/CodeGen/mbackchain-3.c

+// RUN: %clang -mno-backchain --target=s390x-linux -S -emit-llvm -o - %s | FileCheck %s
+
+// CHECK: define void @foo() [[NUW:#[0-9]+]]
+void foo(void) {
+}
+
+// CHECK-NOT: "backchain"

cfe/trunk/test/CodeGen/mbackchain.c

+// RUN: %clang_cc1 -mbackchain -triple s390x-linux -emit-llvm -o - %s | FileCheck %s
+
+// CHECK: define void @foo() [[NUW:#[0-9]+]]
+void foo(void) {
+}
+
+// CHECK: attributes [[NUW]] = { {{.*}} "backchain" {{.*}} }