Revert "Merging r311823: (+update ClangCommandLineReference.rst)"

This reverts commit 544c436. Revert all changed related to r310983. This introduces an ABI break that we don't want, but it also introduces build issues that we haven't fixed yet. Revert at least until we figure the build issues out.

Author: fredriss

docs/ClangCommandLineReference.rst

@@ -656,10 +656,6 @@ Pass <arg> to the assembler
 
 Pass <arg> to the clang compiler
 
-.. option:: -fclang-abi-compat=<version>
-
-Attempt to match the ABI of Clang <version>
-
 .. option:: -fcomment-block-commands=<arg>,<arg2>...
 
 Treat each comma separated argument in <arg> as a documentation comment block command

include/clang/Driver/Options.td

@@ -716,9 +716,6 @@ def fbuiltin : Flag<["-"], "fbuiltin">, Group<f_Group>;
 def fbuiltin_module_map : Flag <["-"], "fbuiltin-module-map">, Group<f_Group>,
  Flags<[DriverOption]>, HelpText<"Load the clang builtins module map file.">;
 def fcaret_diagnostics : Flag<["-"], "fcaret-diagnostics">, Group<f_Group>;
-def fclang_abi_compat_EQ : Joined<["-"], "fclang-abi-compat=">, Group<f_clang_Group>,
- Flags<[CC1Option]>, MetaVarName<"<version>">, Values<"<major>.<minor>,latest">,
- HelpText<"Attempt to match the ABI of Clang <version>">;
 def fclasspath_EQ : Joined<["-"], "fclasspath=">, Group<f_Group>;
 def fcolor_diagnostics : Flag<["-"], "fcolor-diagnostics">, Group<f_Group>,
  Flags<[CoreOption, CC1Option]>, HelpText<"Use colors in diagnostics">;

include/clang/Frontend/CodeGenOptions.def

@@ -120,10 +120,6 @@ CODEGENOPT(NoZeroInitializedInBSS , 1, 0) ///< -fno-zero-initialized-in-bss.
 ENUM_CODEGENOPT(ObjCDispatchMethod, ObjCDispatchMethodKind, 2, Legacy)
 CODEGENOPT(OmitLeafFramePointer , 1, 0) ///< Set when -momit-leaf-frame-pointer is
  ///< enabled.
-
-/// A version of Clang that we should attempt to be ABI-compatible with.
-ENUM_CODEGENOPT(ClangABICompat, ClangABI, 4, ClangABI::Latest)
-
 VALUE_CODEGENOPT(OptimizationLevel, 2, 0) ///< The -O[0-3] option specified.
 VALUE_CODEGENOPT(OptimizeSize, 2, 0) ///< If -Os (==1) or -Oz (==2) is specified.
 

include/clang/Frontend/CodeGenOptions.h

@@ -69,23 +69,6 @@ class CodeGenOptions : public CodeGenOptionsBase {
  LocalExecTLSModel
  };
 
- /// Clang versions with different platform ABI conformance.
- enum class ClangABI {
- /// Attempt to be ABI-compatible with code generated by Clang 3.8.x
- /// (SVN r257626). This causes <1 x long long> to be passed in an
- /// integer register instead of an SSE register on x64_64.
- Ver3_8,
-
- /// Attempt to be ABI-compatible with code generated by Clang 4.0.x
- /// (SVN r291814). This causes move operations to be ignored when
- /// determining whether a class type can be passed or returned directly.
- Ver4,
-
- /// Conform to the underlying platform's C and C++ ABIs as closely
- /// as we can.
- Latest
- };
-
  enum StructReturnConventionKind {
  SRCK_Default, // No special option was passed.
  SRCK_OnStack, // Small structs on the stack (-fpcc-struct-return).

lib/CodeGen/ABIInfo.h

@@ -24,7 +24,6 @@ namespace llvm {
 
 namespace clang {
  class ASTContext;
- class CodeGenOptions;
  class TargetInfo;
 
 namespace CodeGen {
@@ -69,7 +68,6 @@ namespace swiftcall {
  llvm::LLVMContext &getVMContext() const;
  const llvm::DataLayout &getDataLayout() const;
  const TargetInfo &getTarget() const;
- const CodeGenOptions &getCodeGenOpts() const;
 
  /// Return the calling convention to use for system runtime
  /// functions.

lib/CodeGen/CodeGenTypes.cpp

@@ -44,10 +44,6 @@ CodeGenTypes::~CodeGenTypes() {
  delete &*I++;
 }
 
-const CodeGenOptions &CodeGenTypes::getCodeGenOpts() const {
- return CGM.getCodeGenOpts();
-}
-
 void CodeGenTypes::addRecordTypeName(const RecordDecl *RD,
  llvm::StructType *Ty,
  StringRef suffix) {

lib/CodeGen/CodeGenTypes.h

@@ -178,7 +178,6 @@ class CodeGenTypes {
  const TargetInfo &getTarget() const { return Target; }
  CGCXXABI &getCXXABI() const { return TheCXXABI; }
  llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
- const CodeGenOptions &getCodeGenOpts() const;
 
  /// ConvertType - Convert type T into a llvm::Type.
  llvm::Type *ConvertType(QualType T);

lib/CodeGen/ItaniumCXXABI.cpp

@@ -62,20 +62,9 @@ class ItaniumCXXABI : public CodeGen::CGCXXABI {
 
  bool classifyReturnType(CGFunctionInfo &FI) const override;
 
- bool passClassIndirect(const CXXRecordDecl *RD) const {
- // Clang <= 4 used the pre-C++11 rule, which ignores move operations.
- // The PS4 platform ABI follows the behavior of Clang 3.2.
- if (CGM.getCodeGenOpts().getClangABICompat() <=
- CodeGenOptions::ClangABI::Ver4 ||
- CGM.getTriple().getOS() == llvm::Triple::PS4)
- return RD->hasNonTrivialDestructor() ||
- RD->hasNonTrivialCopyConstructor();
- return !canCopyArgument(RD);
- }
-
  RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override {
  // If C++ prohibits us from making a copy, pass by address.
- if (passClassIndirect(RD))
+ if (!canCopyArgument(RD))
  return RAA_Indirect;
  return RAA_Default;
  }
@@ -1007,7 +996,7 @@ bool ItaniumCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
  return false;
 
  // If C++ prohibits us from making a copy, return by address.
- if (passClassIndirect(RD)) {
+ if (!canCopyArgument(RD)) {
  auto Align = CGM.getContext().getTypeAlignInChars(FI.getReturnType());
  FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
  return true;

lib/CodeGen/TargetInfo.cpp

@@ -183,11 +183,7 @@ const TargetInfo &ABIInfo::getTarget() const {
  return CGT.getTarget();
 }
 
-const CodeGenOptions &ABIInfo::getCodeGenOpts() const {
- return CGT.getCodeGenOpts();
-}
-
-bool ABIInfo::isAndroid() const { return getTarget().getTriple().isAndroid(); }
+bool ABIInfo:: isAndroid() const { return getTarget().getTriple().isAndroid(); }
 
 bool ABIInfo::isHomogeneousAggregateBaseType(QualType Ty) const {
  return false;
@@ -2099,14 +2095,9 @@ class X86_64ABIInfo : public SwiftABIInfo {
  return !getTarget().getTriple().isOSDarwin();
  }
 
- /// GCC classifies <1 x long long> as SSE but some platform ABIs choose to
- /// classify it as INTEGER (for compatibility with older clang compilers).
+ /// GCC classifies <1 x long long> as SSE but compatibility with older clang
+ // compilers require us to classify it as INTEGER.
  bool classifyIntegerMMXAsSSE() const {
- // Clang <= 3.8 did not do this.
- if (getCodeGenOpts().getClangABICompat() <=
- CodeGenOptions::ClangABI::Ver3_8)
- return false;
-
  const llvm::Triple &Triple = getTarget().getTriple();
  if (Triple.isOSDarwin() || Triple.getOS() == llvm::Triple::PS4)
  return false;

lib/Driver/ToolChains/Clang.cpp

@@ -2864,9 +2864,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
  addPGOAndCoverageFlags(C, D, Output, Args, CmdArgs);
 
- if (auto *ABICompatArg = Args.getLastArg(options::OPT_fclang_abi_compat_EQ))
- ABICompatArg->render(Args, CmdArgs);
-
  // Add runtime flag for PS4 when PGO or Coverage are enabled.
  if (getToolChain().getTriple().isPS4CPU())
  PS4cpu::addProfileRTArgs(getToolChain(), Args, CmdArgs);