PR4941: Add support for -fno-builtin-foo options.

[mcrosier]

Summary

The changes adds support for -fno-builtin-foo options.

This addresses PR4941 and rdar://6756912.

Please take a look.

Chad

[mcrosier]

Ping.

[hfinkel]

Can you use a StringSet instead of a vector and avoid all (most) of the code iterating over the vector of builtins being disabled?

lib/Frontend/CompilerInvocation.cpp

147

I'd remove this; there's no need for Clang to know about all functions that the optimizer knows about, and thus for which adding the nobuiltin attribute might be useful.

[mcrosier]

In D15195#307136, @hfinkel wrote:

Can you use a StringSet instead of a vector and avoid all (most) of the code iterating over the vector of builtins being disabled?

Hi Hal,
I began converting the code to use StringSets, but I soon realized this wasn't as trivial of a change as one would hope. There are number of places where the LangOptions and CodeGenOptions are copied (e.g., Lexer.cpp:133, PrettyPrinter.h:38, ModuleBuilder.cpp:66) . Unfortunately, this copying requires a copy constructor for the StringSets. I'd prefer to stick with a simple string vector as any code saved by not iterating over the vector is lost on the copy constructor implementation. FWIW, I also don't believe this to be performance critical code.. Please let me know your thoughts.

Chad

Chad

[hfinkel]

In D15195#310395, @mcrosier wrote:

In D15195#307136, @hfinkel wrote:

Can you use a StringSet instead of a vector and avoid all (most) of the code iterating over the vector of builtins being disabled?

Hi Hal,
I began converting the code to use StringSets, but I soon realized this wasn't as trivial of a change as one would hope. There are number of places where the LangOptions and CodeGenOptions are copied (e.g., Lexer.cpp:133, PrettyPrinter.h:38, ModuleBuilder.cpp:66) . Unfortunately, this copying requires a copy constructor for the StringSets. I'd prefer to stick with a simple string vector as any code saved by not iterating over the vector is lost on the copy constructor implementation. FWIW, I also don't believe this to be performance critical code.. Please let me know your thoughts.

In that case, let's stick with the vector for now. We can always improve things later if we'd like.

[bob.wilson]

Regarding the FIXME in lib/Frontend/CompilerInvocation.cpp: I agree with Hal that you can remove that. We used to complain about unsupported -fno-builtin-* options (and until now they have *all* been unsupported), but in r191434, Rafael changed clang to silently ignore those options, with the explanation that it matches gcc's behavior. Assuming that gcc has not changed in that regard, it makes sense that we should continue to ignore -fno-builtin-* for unsupported options.

[mcrosier]

Remove the FIXME, per Hal and Bob's request. I confirmed that gcc does not warn for invalid -fno-builtin-foo options.
Also, pass the vector by reference and insert, rather than making an unnecessary copy on the return in CompilerInvocation.

[mcrosier]

Ping. I promise this is fairly straight forward. :)

[mcrosier]

Ping.

[bob.wilson]

This looks good to me. Thanks for working on this!

[mcrosier]

Committed in r256937. Thanks, Bob.

include/clang/Basic/Builtins.h

public:
   bool isAuxBuiltinID(unsigned ID) const {
     return ID >= (Builtin::FirstTSBuiltin + TSRecords.size());
   }
 
   /// Return real buitin ID (i.e. ID it would have furing compilation
   /// for AuxTarget).
   unsigned getAuxBuiltinID(unsigned ID) const { return ID - TSRecords.size(); }
 
+  /// Returns true if this is a libc/libm function without the '__builtin_'
+  /// prefix.
+  static bool isBuiltinFunc(const char *Name);
+
 private:
   const Info &getRecord(unsigned ID) const;
 
   /// \brief Is this builtin supported according to the given language options?
   bool builtinIsSupported(const Builtin::Info &BuiltinInfo,
                           const LangOptions &LangOpts);
 
   /// \brief Helper function for isPrintfLike and isScanfLike.

include/clang/Basic/LangOptions.h

public:
   /// \brief The names of any features to enable in module 'requires' decls
   /// in addition to the hard-coded list in Module.cpp and the target features.
   ///
   /// This list is sorted.
   std::vector<std::string> ModuleFeatures;
 
   /// \brief Options for parsing comments.
   CommentOptions CommentOpts;
-  
+  /// \brief A list of all -fno-builtin-* function names (e.g., memset).
+  std::vector<std::string> NoBuiltinFuncs;
+
   LangOptions();
 
   // Define accessors/mutators for language options of enumeration type.
 #define LANGOPT(Name, Bits, Default, Description) 
 #define ENUM_LANGOPT(Name, Type, Bits, Default, Description) \
   Type get##Name() const { return static_cast<Type>(Name); } \
   void set##Name(Type Value) { Name = static_cast<unsigned>(Value); }  
 #include "clang/Basic/LangOptions.def"
#include "clang/Basic/LangOptions.def"
 
   bool isCompatibleWithMSVC(MSVCMajorVersion MajorVersion) const {
     return MSCompatibilityVersion >= MajorVersion * 10000000U;
   }
 
   /// \brief Reset all of the options that are not considered when building a
   /// module.
   void resetNonModularOptions();
+
+  /// \brief Is this a libc/libm function that is no longer recognized as a
+  /// builtin because a -fno-builtin-* option has been specified?
+  bool isNoBuiltinFunc(const char *Name) const;
 };
 
 /// \brief Floating point control options
 class FPOptions {
 public:
   unsigned fp_contract : 1;
 
   FPOptions() : fp_contract(0) {}

include/clang/Driver/Options.td

 def fno_asynchronous_unwind_tables : Flag<["-"], "fno-asynchronous-unwind-tables">, Group<f_Group>;
 def fno_assume_sane_operator_new : Flag<["-"], "fno-assume-sane-operator-new">, Group<f_Group>,
   HelpText<"Don't assume that C++'s global operator new can't alias any pointer">,
   Flags<[CC1Option]>;
 def fno_blocks : Flag<["-"], "fno-blocks">, Group<f_Group>;
 def fno_borland_extensions : Flag<["-"], "fno-borland-extensions">, Group<f_Group>;
 def fno_builtin : Flag<["-"], "fno-builtin">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Disable implicit builtin knowledge of functions">;
-def fno_builtin_ : Joined<["-"], "fno-builtin-">, Group<clang_ignored_f_Group>,
+def fno_builtin_ : Joined<["-"], "fno-builtin-">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Disable implicit builtin knowledge of a specific function">;
 def fno_math_builtin : Flag<["-"], "fno-math-builtin">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Disable implicit builtin knowledge of math functions">;
 def fno_caret_diagnostics : Flag<["-"], "fno-caret-diagnostics">, Group<f_Group>,
  Flags<[CC1Option]>;
 def fno_color_diagnostics : Flag<["-"], "fno-color-diagnostics">, Group<f_Group>,
   Flags<[CoreOption, CC1Option]>;
 def fno_diagnostics_color : Flag<["-"], "fno-diagnostics-color">, Group<f_Group>,

include/clang/Frontend/CodeGenOptions.h

public:
 
   /// Set of sanitizer checks that are non-fatal (i.e. execution should be
   /// continued when possible).
   SanitizerSet SanitizeRecover;
 
   /// Set of sanitizer checks that trap rather than diagnose.
   SanitizerSet SanitizeTrap;
 
+  /// \brief A list of all -fno-builtin-* function names (e.g., memset).
+  std::vector<std::string> NoBuiltinFuncs;
+
 public:
   // Define accessors/mutators for code generation options of enumeration type.
 #define CODEGENOPT(Name, Bits, Default)
 #define ENUM_CODEGENOPT(Name, Type, Bits, Default) \
   Type get##Name() const { return static_cast<Type>(Name); } \
   void set##Name(Type Value) { Name = static_cast<unsigned>(Value); }
 #include "clang/Frontend/CodeGenOptions.def"
 
   CodeGenOptions();
+
+  /// \brief Is this a libc/libm function that is no longer recognized as a
+  /// builtin because a -fno-builtin-* option has been specified?
+  bool isNoBuiltinFunc(const char *Name) const;
+
+  const std::vector<std::string> &getNoBuiltinFuncs() const {
+    return NoBuiltinFuncs;
+  }
 };
 
 }  // end namespace clang
 
 #endif

lib/Basic/Builtins.cpp

 void Builtin::Context::InitializeTarget(const TargetInfo &Target,
                                         const TargetInfo *AuxTarget) {
   assert(TSRecords.empty() && "Already initialized target?");
   TSRecords = Target.getTargetBuiltins();
   if (AuxTarget)
     AuxTSRecords = AuxTarget->getTargetBuiltins();
 }
 
+bool Builtin::Context::isBuiltinFunc(const char *Name) {
+  StringRef FuncName(Name);
+  for (unsigned i = Builtin::NotBuiltin + 1; i != Builtin::FirstTSBuiltin; ++i)
+    if (FuncName.equals(BuiltinInfo[i].Name))
+      return strchr(BuiltinInfo[i].Attributes, 'f') != nullptr;
+
+  return false;
+}
+
 bool Builtin::Context::builtinIsSupported(const Builtin::Info &BuiltinInfo,
                                           const LangOptions &LangOpts) {
-  bool BuiltinsUnsupported = LangOpts.NoBuiltin &&
-                             strchr(BuiltinInfo.Attributes, 'f');
+  bool BuiltinsUnsupported =
+      (LangOpts.NoBuiltin || LangOpts.isNoBuiltinFunc(BuiltinInfo.Name)) &&
   bool MathBuiltinsUnsupported =
     LangOpts.NoMathBuiltin && BuiltinInfo.HeaderName &&
     llvm::StringRef(BuiltinInfo.HeaderName).equals("math.h");
   bool GnuModeUnsupported = !LangOpts.GNUMode && (BuiltinInfo.Langs & GNU_LANG);
   bool MSModeUnsupported =
       !LangOpts.MicrosoftExt && (BuiltinInfo.Langs & MS_LANG);
   bool ObjCUnsupported = !LangOpts.ObjC1 && BuiltinInfo.Langs == OBJC_LANG;
   return !BuiltinsUnsupported && !MathBuiltinsUnsupported &&

lib/Basic/LangOptions.cpp

 //===--- LangOptions.cpp - C Language Family Language Options ---*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file defines the LangOptions class.
 //
 //===----------------------------------------------------------------------===//
 #include "clang/Basic/LangOptions.h"
+#include "llvm/ADT/StringRef.h"
 
 using namespace clang;
 
 LangOptions::LangOptions() {
 #define LANGOPT(Name, Bits, Default, Description) Name = Default;
 #define ENUM_LANGOPT(Name, Type, Bits, Default, Description) set##Name(Default);
 #include "clang/Basic/LangOptions.def"
 }
#include "clang/Basic/LangOptions.def"
   // sanitizer options (this affects __has_feature(address_sanitizer) etc).
   Sanitize.clear();
   SanitizerBlacklistFiles.clear();
 
   CurrentModule.clear();
   ImplementationOfModule.clear();
 }
 
+bool LangOptions::isNoBuiltinFunc(const char *Name) const {
+  StringRef FuncName(Name);
+  for (unsigned i = 0, e = NoBuiltinFuncs.size(); i != e; ++i)
+    if (FuncName.equals(NoBuiltinFuncs[i]))
+      return true;
+  return false;
+}

lib/CodeGen/BackendUtil.cpp

static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
 }
 
 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
                                          const CodeGenOptions &CodeGenOpts) {
   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
   if (!CodeGenOpts.SimplifyLibCalls)
     TLII->disableAllFunctions();
+  else {
+    // Disable individual libc/libm calls in TargetLibraryInfo.
+    LibFunc::Func F;
+    for (auto &FuncName : CodeGenOpts.getNoBuiltinFuncs())
+      if (TLII->getLibFunc(FuncName, F))
+        TLII->setUnavailable(F);
+  }
 
   switch (CodeGenOpts.getVecLib()) {
   case CodeGenOptions::Accelerate:
     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
     break;
   default:
     break;
   }

lib/CodeGen/CGCall.cpp

static void AddAttributesFromFunctionProtoType(ASTContext &Ctx,
   if (!FPT)
     return;
 
   if (!isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) &&
       FPT->isNothrow(Ctx))
     FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
 }
 
-void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
-                                           CGCalleeInfo CalleeInfo,
-                                           AttributeListType &PAL,
-                                           unsigned &CallingConv,
-                                           bool AttrOnCallSite) {
+void CodeGenModule::ConstructAttributeList(
+    StringRef Name, const CGFunctionInfo &FI, CGCalleeInfo CalleeInfo,
+    AttributeListType &PAL, unsigned &CallingConv, bool AttrOnCallSite) {
   llvm::AttrBuilder FuncAttrs;
   llvm::AttrBuilder RetAttrs;
   bool HasOptnone = false;
 
   CallingConv = FI.getEffectiveCallingConvention();
 
   if (FI.isNoReturn())
     FuncAttrs.addAttribute(llvm::Attribute::NoReturn);
void CodeGenModule::ConstructAttributeList(
   if (CodeGenOpts.NoImplicitFloat)
     FuncAttrs.addAttribute(llvm::Attribute::NoImplicitFloat);
   if (CodeGenOpts.EnableSegmentedStacks &&
       !(TargetDecl && TargetDecl->hasAttr<NoSplitStackAttr>()))
     FuncAttrs.addAttribute("split-stack");
 
   if (AttrOnCallSite) {
     // Attributes that should go on the call site only.
-    if (!CodeGenOpts.SimplifyLibCalls)
+    if (!CodeGenOpts.SimplifyLibCalls ||
+        CodeGenOpts.isNoBuiltinFunc(Name.data()))
       FuncAttrs.addAttribute(llvm::Attribute::NoBuiltin);
     if (!CodeGenOpts.TrapFuncName.empty())
       FuncAttrs.addAttribute("trap-func-name", CodeGenOpts.TrapFuncName);
   } else {
     // Attributes that should go on the function, but not the call site.
     if (!CodeGenOpts.DisableFPElim) {
       FuncAttrs.addAttribute("no-frame-pointer-elim", "false");
     } else if (CodeGenOpts.OmitLeafFramePointer) {
if (IRFunctionArgs.hasInallocaArg() &&
         i == IRFunctionArgs.getInallocaArgNo())
       continue;
     if (i < IRFuncTy->getNumParams())
       assert(IRCallArgs[i]->getType() == IRFuncTy->getParamType(i));
   }
 
   unsigned CallingConv;
   CodeGen::AttributeListType AttributeList;
-  CGM.ConstructAttributeList(CallInfo, CalleeInfo, AttributeList, CallingConv,
-                             true);
+  CGM.ConstructAttributeList(Callee->getName(), CallInfo, CalleeInfo,
+                             AttributeList, CallingConv,
+                             /*AttrOnCallSite=*/true);
   llvm::AttributeSet Attrs = llvm::AttributeSet::get(getLLVMContext(),
                                                      AttributeList);
 
   bool CannotThrow;
   if (currentFunctionUsesSEHTry()) {
     // SEH cares about asynchronous exceptions, everything can "throw."
     CannotThrow = false;
   } else if (isCleanupPadScope() &&

lib/CodeGen/CGVTables.cpp

void CodeGenFunction::EmitMustTailThunk(const CXXMethodDecl *MD,
   // Emit the musttail call manually.  Even if the prologue pushed cleanups, we
   // don't actually want to run them.
   llvm::CallInst *Call = Builder.CreateCall(Callee, Args);
   Call->setTailCallKind(llvm::CallInst::TCK_MustTail);
 
   // Apply the standard set of call attributes.
   unsigned CallingConv;
   CodeGen::AttributeListType AttributeList;
-  CGM.ConstructAttributeList(*CurFnInfo, MD, AttributeList, CallingConv,
-                             /*AttrOnCallSite=*/true);
+  CGM.ConstructAttributeList(Callee->getName(), *CurFnInfo, MD, AttributeList,
+                             CallingConv, /*AttrOnCallSite=*/true);
   llvm::AttributeSet Attrs =
       llvm::AttributeSet::get(getLLVMContext(), AttributeList);
   Call->setAttributes(Attrs);
   Call->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
 
   if (Call->getType()->isVoidTy())
     Builder.CreateRetVoid();
   else

lib/CodeGen/CodeGenModule.h

public:
   bool ReturnTypeUsesFPRet(QualType ResultType);
 
   /// Return true iff the given type uses 'fp2ret' when used as a return type.
   bool ReturnTypeUsesFP2Ret(QualType ResultType);
 
   /// Get the LLVM attributes and calling convention to use for a particular
   /// function type.
   ///
+  /// \param Name - The function name.
   /// \param Info - The function type information.
   /// \param CalleeInfo - The callee information these attributes are being
   /// constructed for. If valid, the attributes applied to this decl may
   /// contribute to the function attributes and calling convention.
   /// \param PAL [out] - On return, the attribute list to use.
   /// \param CallingConv [out] - On return, the LLVM calling convention to use.
-  void ConstructAttributeList(const CGFunctionInfo &Info,
+  void ConstructAttributeList(StringRef Name, const CGFunctionInfo &Info,
                               CGCalleeInfo CalleeInfo, AttributeListType &PAL,
                               unsigned &CallingConv, bool AttrOnCallSite);
 
   // Fills in the supplied string map with the set of target features for the
   // passed in function.
   void getFunctionFeatureMap(llvm::StringMap<bool> &FeatureMap,
                              const FunctionDecl *FD);
 

lib/CodeGen/CodeGenModule.cpp

void CodeGenModule::setFunctionDefinitionAttributes(const FunctionDecl *D,
   setNonAliasAttributes(D, F);
 }
 
 void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D,
                                               const CGFunctionInfo &Info,
                                               llvm::Function *F) {
   unsigned CallingConv;
   AttributeListType AttributeList;
-  ConstructAttributeList(Info, D, AttributeList, CallingConv, false);
+  ConstructAttributeList(F->getName(), Info, D, AttributeList, CallingConv,
+                         false);
   F->setAttributes(llvm::AttributeSet::get(getLLVMContext(), AttributeList));
   F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
 }
 
 /// Determines whether the language options require us to model
 /// unwind exceptions.  We treat -fexceptions as mandating this
 /// except under the fragile ObjC ABI with only ObjC exceptions
 /// enabled.  This means, for example, that C with -fexceptions

lib/Driver/Tools.cpp

   if (Arg *A = Args.getLastArg(options::OPT_fprofile_sample_use_EQ)) {
     StringRef fname = A->getValue();
     if (!llvm::sys::fs::exists(fname))
       D.Diag(diag::err_drv_no_such_file) << fname;
     else
       A->render(Args, CmdArgs);
   }
 
-  // -fbuiltin is default unless -mkernel is used
-  if (!Args.hasFlag(options::OPT_fbuiltin, options::OPT_fno_builtin,
-                    !Args.hasArg(options::OPT_mkernel)))
+  // -fbuiltin is default unless -mkernel is used.
+  bool UseBuiltins =
+      Args.hasFlag(options::OPT_fbuiltin, options::OPT_fno_builtin,
+                   !Args.hasArg(options::OPT_mkernel));
+  if (!UseBuiltins)
     CmdArgs.push_back("-fno-builtin");
 
+  // -ffreestanding implies -fno-builtin.
+  if (Args.hasArg(options::OPT_ffreestanding))
+    UseBuiltins = false;
+
+  // Process the -fno-builtin-* options.
+  for (const auto &Arg : Args) {
+    const Option &O = Arg->getOption();
+    if (!O.matches(options::OPT_fno_builtin_))
+      continue;
+
+    Arg->claim();
+    // If -fno-builtin is specified, then there's no need to pass the option to
+    // the frontend.
+    if (!UseBuiltins)
+      continue;
+
+    StringRef FuncName = Arg->getValue();
+    CmdArgs.push_back(Args.MakeArgString("-fno-builtin-" + FuncName));
+  }
+
   if (!Args.hasFlag(options::OPT_fassume_sane_operator_new,
                     options::OPT_fno_assume_sane_operator_new))
     CmdArgs.push_back("-fno-assume-sane-operator-new");
 
   // -fblocks=0 is default.
   if (Args.hasFlag(options::OPT_fblocks, options::OPT_fno_blocks,
                    getToolChain().IsBlocksDefault()) ||
       (Args.hasArg(options::OPT_fgnu_runtime) &&

lib/Frontend/CodeGenOptions.cpp

 #define CODEGENOPT(Name, Bits, Default) Name = Default;
 #define ENUM_CODEGENOPT(Name, Type, Bits, Default) set##Name(Default);
 #include "clang/Frontend/CodeGenOptions.def"
 
   RelocationModel = "pic";
   memcpy(CoverageVersion, "402*", 4);
 }
 
+bool CodeGenOptions::isNoBuiltinFunc(const char *Name) const {
+  StringRef FuncName(Name);
+  for (unsigned i = 0, e = NoBuiltinFuncs.size(); i != e; ++i)
+    if (FuncName.equals(NoBuiltinFuncs[i]))
+      return true;
+  return false;
+}
+
 }  // end namespace clang

lib/Frontend/CompilerInvocation.cpp

 //===--- CompilerInvocation.cpp -------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "TestModuleFileExtension.h"
-#include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Basic/Builtins.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/Version.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/Util.h"
+#include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/LangStandard.h"
 #include "clang/Frontend/Utils.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/ModuleFileExtension.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/STLExtras.h"
for (Arg *A : Args.filtered(Group)) {
     } else {
       // Otherwise, add its value (for OPT_W_Joined and similar).
       for (const char *Arg : A->getValues())
         Diagnostics.emplace_back(Arg);
     }
   }
 }
 
+static void getAllNoBuiltinFuncValues(ArgList &Args,
+                                      std::vector<std::string> &Funcs) {
+  SmallVector<const char *, 8> Values;
+  for (const auto &Arg : Args) {
+    const Option &O = Arg->getOption();
+    if (O.matches(options::OPT_fno_builtin_)) {
+      const char *FuncName = Arg->getValue();
+      if (Builtin::Context::isBuiltinFunc(FuncName))
+        Values.push_back(FuncName);
+    }
+  }
+  Funcs.insert(Funcs.end(), Values.begin(), Values.end());
+}
+
 static bool ParseAnalyzerArgs(AnalyzerOptions &Opts, ArgList &Args,
                               DiagnosticsEngine &Diags) {
   using namespace options;
   bool Success = true;
   if (Arg *A = Args.getLastArg(OPT_analyzer_store)) {
     StringRef Name = A->getValue();
     AnalysisStores Value = llvm::StringSwitch<AnalysisStores>(Name)
 #define ANALYSIS_STORE(NAME, CMDFLAG, DESC, CREATFN) \
static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.StructPathTBAA = !Args.hasArg(OPT_no_struct_path_tbaa);
   Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
   Opts.MergeAllConstants = !Args.hasArg(OPT_fno_merge_all_constants);
   Opts.NoCommon = Args.hasArg(OPT_fno_common);
   Opts.NoImplicitFloat = Args.hasArg(OPT_no_implicit_float);
   Opts.OptimizeSize = getOptimizationLevelSize(Args);
   Opts.SimplifyLibCalls = !(Args.hasArg(OPT_fno_builtin) ||
                             Args.hasArg(OPT_ffreestanding));
+  if (Opts.SimplifyLibCalls)
+    getAllNoBuiltinFuncValues(Args, Opts.NoBuiltinFuncs);
   Opts.UnrollLoops =
       Args.hasFlag(OPT_funroll_loops, OPT_fno_unroll_loops,
                    (Opts.OptimizationLevel > 1 && !Opts.OptimizeSize));
   Opts.RerollLoops = Args.hasArg(OPT_freroll_loops);
 
   Opts.DisableIntegratedAS = Args.hasArg(OPT_fno_integrated_as);
   Opts.Autolink = !Args.hasArg(OPT_fno_autolink);
   Opts.SampleProfileFile = Args.getLastArgValue(OPT_fprofile_sample_use_EQ);
#include "clang/Frontend/LangStandards.def"
   Opts.ModulesErrorRecovery = !Args.hasArg(OPT_fno_modules_error_recovery);
   Opts.ImplicitModules = !Args.hasArg(OPT_fno_implicit_modules);
   Opts.CharIsSigned = Opts.OpenCL || !Args.hasArg(OPT_fno_signed_char);
   Opts.WChar = Opts.CPlusPlus && !Args.hasArg(OPT_fno_wchar);
   Opts.ShortWChar = Args.hasFlag(OPT_fshort_wchar, OPT_fno_short_wchar, false);
   Opts.ShortEnums = Args.hasArg(OPT_fshort_enums);
   Opts.Freestanding = Args.hasArg(OPT_ffreestanding);
   Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;
+  if (!Opts.NoBuiltin)
+    getAllNoBuiltinFuncValues(Args, Opts.NoBuiltinFuncs);
   Opts.NoMathBuiltin = Args.hasArg(OPT_fno_math_builtin);
   Opts.AssumeSaneOperatorNew = !Args.hasArg(OPT_fno_assume_sane_operator_new);
   Opts.SizedDeallocation = Args.hasArg(OPT_fsized_deallocation);
   Opts.ConceptsTS = Args.hasArg(OPT_fconcepts_ts);
   Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
   Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
   Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);
   Opts.MathErrno = !Opts.OpenCL && Args.hasArg(OPT_fmath_errno);

test/CodeGen/2007-04-14-FNoBuiltin.c

 // RUN: %clang_cc1 -emit-llvm %s -O2 -fno-builtin -o - | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm %s -O2 -fno-builtin-printf -o - | FileCheck %s
 // Check that -fno-builtin is honored.
 
 extern int printf(const char*, ...);
 
 // CHECK: define {{.*}}void {{.*}}foo(
 void foo(const char *msg) {
   // CHECK: call {{.*}}printf
   printf("%s\n",msg);
 }

test/CodeGen/libcalls-complex.c

 // RUN: %clang_cc1 -fno-builtin -emit-llvm -o - %s -triple i386-unknown-unknown | FileCheck -check-prefix CHECK-YES %s
+// RUN: %clang_cc1 -fno-builtin-crealf -fno-builtin-creal -fno-builtin-creall \
+// RUN:  -fno-builtin-cimagf  -fno-builtin-cimag -fno-builtin-cimagl -emit-llvm \
+// RUN:  -o - %s -triple i386-unknown-unknown | FileCheck -check-prefix CHECK-YES %s
 // RUN: %clang_cc1 -emit-llvm -o - %s -triple i386-unknown-unknown | FileCheck -check-prefix CHECK-NO %s
 
 extern float crealf(float _Complex);
 extern double creal(double _Complex);
 extern long double creall(long double _Complex);
 
 extern float cimagf(float _Complex);
 extern double cimag(double _Complex);

test/CodeGen/libcalls-fno-builtin.c

 // RUN: %clang_cc1 -S -O3 -fno-builtin -o - %s | FileCheck %s
+// RUN: %clang_cc1 -S -O3 -fno-builtin-ceil -fno-builtin-copysign -fno-builtin-cos \
+// RUN:  -fno-builtin-fabs -fno-builtin-floor -fno-builtin-strcat -fno-builtin-strncat \
+// RUN:  -fno-builtin-strchr -fno-builtin-strrchr -fno-builtin-strcmp -fno-builtin-strncmp \
+// RUN:  -fno-builtin-strcpy -fno-builtin-stpcpy -fno-builtin-strncpy -fno-builtin-strlen \
+// RUN:  -fno-builtin-strpbrk -fno-builtin-strspn -fno-builtin-strtod -fno-builtin-strtof \
+// RUN:  -fno-builtin-strtold -fno-builtin-strtol -fno-builtin-strtoll -fno-builtin-strtoul \
+// RUN:  -fno-builtin-strtoull -o - %s | FileCheck %s
 // rdar://10551066
 
 typedef __SIZE_TYPE__ size_t;
 
 double ceil(double x);
 double copysign(double,double);
 double cos(double x);
 double fabs(double x);

test/CodeGen/nobuiltin.c

 // RUN: %clang_cc1 -fno-builtin -O1 -S -o - %s | FileCheck %s
+// RUN: %clang_cc1 -fno-builtin-memset -O1 -S -o - %s | FileCheck -check-prefix=MEMSET %s
 
 void PR13497() {
   char content[2];
   // make sure we don't optimize this call to strcpy()
   // CHECK: __strcpy_chk
   __builtin___strcpy_chk(content, "", 1);
 }
+
+void PR4941(char *s) {
+  // Make sure we don't optimize this loop to a memset().
+  // MEMSET-LABEL: PR4941:
+  // MEMSET-NOT: memset
+  for (unsigned i = 0; i < 8192; ++i)
+    s[i] = 0;
+}

test/Sema/implicit-builtin-freestanding.c

 // RUN: %clang_cc1 -fsyntax-only -verify -ffreestanding %s
+// RUN: %clang_cc1 -fsyntax-only -verify -fno-builtin %s
+// RUN: %clang_cc1 -fsyntax-only -verify -fno-builtin-malloc %s
 // expected-no-diagnostics
 
 int malloc(int a) { return a; }