[clang][PowerPC] Add flag to enable compatibility with GNU for comple…

…x arguments

Fixes : #56023

https://godbolt.org/z/1bsW1sKMs

newFlag : -fcomplex-ppc-gnu-abi

GNU uses GPRs for complex parameters and return values storing for PowerPC-32bit,
which can be enabled which above flag.
Intent of this patch is to make clang compatible with GNU libraries of complex.

clang/include/clang/Basic/CodeGenOptions.def

@@ -213,6 +213,8 @@ CODEGENOPT(MCDCCoverage , 1, 0) ///< Enable MC/DC code coverage criteria.
 
   /// If -fpcc-struct-return or -freg-struct-return is specified.
 ENUM_CODEGENOPT(StructReturnConvention, StructReturnConventionKind, 2, SRCK_Default)
+  /// If -fcomplex-ppc-gnu-abi for ppc32
+ENUM_CODEGENOPT(ComplexInRegABI, ComplexArgumentConventionKind, 2, CMPLX_Default)
 
 CODEGENOPT(RelaxAll          , 1, 0) ///< Relax all machine code instructions.
 CODEGENOPT(RelaxedAliasing   , 1, 0) ///< Set when -fno-strict-aliasing is enabled.

clang/include/clang/Basic/CodeGenOptions.h

@@ -78,6 +78,13 @@ class CodeGenOptions : public CodeGenOptionsBase {
     SRCK_InRegs    // Small structs in registers (-freg-struct-return).
   };
 
+  enum ComplexArgumentConventionKind {
+    CMPLX_Default,
+    CMPLX_OnStack,
+    CMPLX_OnGPR, // if ppc32 -fcomplex-ppc-gnu-abi
+    CMPLX_OnFPR
+  };
+
   enum ProfileInstrKind {
     ProfileNone,       // Profile instrumentation is turned off.
     ProfileClangInstr, // Clang instrumentation to generate execution counts

clang/include/clang/Driver/Options.td

@@ -2540,6 +2540,10 @@ def ffp_contract : Joined<["-"], "ffp-contract=">, Group<f_Group>,
   HelpText<"Form fused FP ops (e.g. FMAs)">,
   Values<"fast,on,off,fast-honor-pragmas">;
 
+def fcomplex_ppc_gnu_abi : Flag<["-"], "fcomplex-ppc-gnu-abi">, Group<f_Group>, Visibility<[ClangOption, CC1Option]>,
+  DocBrief<"Follow the GNU ABI, store Complex values in GPR instead of stack for PowerPC-32">,
+  HelpText<"Store Complex values in GPR instead of stack for PowerPC-32">;
+
 defm strict_float_cast_overflow : BoolFOption<"strict-float-cast-overflow",
   CodeGenOpts<"StrictFloatCastOverflow">, DefaultTrue,
   NegFlag<SetFalse, [], [ClangOption, CC1Option],

clang/lib/CodeGen/CodeGenModule.cpp

@@ -184,11 +184,13 @@ createTargetCodeGenInfo(CodeGenModule &CGM) {
 
     bool IsSoftFloat =
         CodeGenOpts.FloatABI == "soft" || Target.hasFeature("spe");
-    return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
+    unsigned RLen = Target.getPointerWidth(LangAS::Default);
+    return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat, RLen);
   }
   case llvm::Triple::ppcle: {
     bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
-    return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
+    unsigned RLen = Target.getPointerWidth(LangAS::Default);
+    return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat, RLen);
   }
   case llvm::Triple::ppc64:
     if (Triple.isOSAIX())

clang/lib/CodeGen/TargetInfo.h

@@ -486,7 +486,8 @@ std::unique_ptr<TargetCodeGenInfo>
 createAIXTargetCodeGenInfo(CodeGenModule &CGM, bool Is64Bit);
 
 std::unique_ptr<TargetCodeGenInfo>
-createPPC32TargetCodeGenInfo(CodeGenModule &CGM, bool SoftFloatABI);
+createPPC32TargetCodeGenInfo(CodeGenModule &CGM, bool SoftFloatABI,
+                             unsigned RLen);
 
 std::unique_ptr<TargetCodeGenInfo>
 createPPC64TargetCodeGenInfo(CodeGenModule &CGM);

clang/lib/CodeGen/Targets/PPC.cpp

@@ -271,22 +271,33 @@ namespace {
 class PPC32_SVR4_ABIInfo : public DefaultABIInfo {
   bool IsSoftFloatABI;
   bool IsRetSmallStructInRegABI;
+  bool isComplexInRegABI;
+  // Size of GPR in bits
+  unsigned RLen;
+  static const int NumArgGPRs = 8;
 
   CharUnits getParamTypeAlignment(QualType Ty) const;
+  ABIArgInfo handleComplex(QualType Ty, uint64_t &TypeSize) const;
 
 public:
   PPC32_SVR4_ABIInfo(CodeGen::CodeGenTypes &CGT, bool SoftFloatABI,
-                     bool RetSmallStructInRegABI)
+                     bool RetSmallStructInRegABI, unsigned RLen,
+                     bool ComplexInRegABI)
       : DefaultABIInfo(CGT), IsSoftFloatABI(SoftFloatABI),
-        IsRetSmallStructInRegABI(RetSmallStructInRegABI) {}
+        IsRetSmallStructInRegABI(RetSmallStructInRegABI),
+        isComplexInRegABI(ComplexInRegABI), RLen(RLen) {}
 
   ABIArgInfo classifyReturnType(QualType RetTy) const;
+  ABIArgInfo classifyArgumentType(QualType Ty, int &ArgGPRsLeft) const;
 
   void computeInfo(CGFunctionInfo &FI) const override {
+
+    int ArgGPRsLeft = NumArgGPRs;
+
     if (!getCXXABI().classifyReturnType(FI))
       FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
     for (auto &I : FI.arguments())
-      I.info = classifyArgumentType(I.type);
+      I.info = classifyArgumentType(I.type, ArgGPRsLeft);
   }
 
   Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
@@ -296,9 +307,11 @@ class PPC32_SVR4_ABIInfo : public DefaultABIInfo {
 class PPC32TargetCodeGenInfo : public TargetCodeGenInfo {
 public:
   PPC32TargetCodeGenInfo(CodeGenTypes &CGT, bool SoftFloatABI,
-                         bool RetSmallStructInRegABI)
+                         bool RetSmallStructInRegABI, unsigned RLen,
+                         bool ComplexInRegABI)
       : TargetCodeGenInfo(std::make_unique<PPC32_SVR4_ABIInfo>(
-            CGT, SoftFloatABI, RetSmallStructInRegABI)) {}
+            CGT, SoftFloatABI, RetSmallStructInRegABI, RLen, ComplexInRegABI)) {
+  }
 
   static bool isStructReturnInRegABI(const llvm::Triple &Triple,
                                      const CodeGenOptions &Opts);
@@ -337,12 +350,77 @@ CharUnits PPC32_SVR4_ABIInfo::getParamTypeAlignment(QualType Ty) const {
   return CharUnits::fromQuantity(4);
 }
 
+ABIArgInfo PPC32_SVR4_ABIInfo::handleComplex(QualType Ty,
+                                             uint64_t &TypeSize) const {
+
+  assert(Ty->isAnyComplexType());
+  llvm::Type *ElemTy;
+  unsigned SizeRegs;
+
+  if (TypeSize == 64) {
+    ElemTy = llvm::Type::getInt64Ty(getVMContext());
+    SizeRegs = 1;
+  } else {
+    ElemTy = llvm::Type::getInt32Ty(getVMContext());
+    SizeRegs = (TypeSize + 31) / 32;
+  }
+  return ABIArgInfo::getDirect(llvm::ArrayType::get(ElemTy, SizeRegs));
+}
+
+ABIArgInfo PPC32_SVR4_ABIInfo::classifyArgumentType(QualType Ty,
+                                                    int &ArgGPRsLeft) const {
+
+  assert(ArgGPRsLeft <= NumArgGPRs && "Arg GPR tracking underflow");
+  Ty = useFirstFieldIfTransparentUnion(Ty);
+
+  ASTContext &Context = getContext();
+
+  uint64_t TypeSize = Context.getTypeSize(Ty);
+
+  if (isComplexInRegABI && Ty->isAnyComplexType() &&
+      TypeSize <= RLen * ArgGPRsLeft) {
+    ArgGPRsLeft -= TypeSize / RLen;
+    return handleComplex(Ty, TypeSize);
+  }
+
+  if (isAggregateTypeForABI(Ty)) {
+    if (ArgGPRsLeft)
+      ArgGPRsLeft -= 1;
+    // Records with non-trivial destructors/copy-constructors should not be
+    // passed by value.
+    if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI())) {
+      return getNaturalAlignIndirect(Ty, RAA == CGCXXABI::RAA_DirectInMemory);
+    }
+    return getNaturalAlignIndirect(Ty);
+  }
+
+  if (!Ty->isFloatingType()) {
+    if (TypeSize > RLen && TypeSize <= 2 * RLen)
+      ArgGPRsLeft -= 2;
+    else
+      ArgGPRsLeft--;
+  }
+
+  // Treat an enum type as its underlying type.
+  if (const EnumType *EnumTy = Ty->getAs<EnumType>())
+    Ty = EnumTy->getDecl()->getIntegerType();
+
+  if (const auto *EIT = Ty->getAs<BitIntType>())
+    if (EIT->getNumBits() >
+        Context.getTypeSize(Context.getTargetInfo().hasInt128Type()
+                                ? Context.Int128Ty
+                                : Context.LongLongTy))
+      return getNaturalAlignIndirect(Ty);
+
+  return (isPromotableIntegerTypeForABI(Ty) ? ABIArgInfo::getExtend(Ty)
+                                            : ABIArgInfo::getDirect());
+}
+
 ABIArgInfo PPC32_SVR4_ABIInfo::classifyReturnType(QualType RetTy) const {
-  uint64_t Size;
+  uint64_t Size = getContext().getTypeSize(RetTy);
 
   // -msvr4-struct-return puts small aggregates in GPR3 and GPR4.
-  if (isAggregateTypeForABI(RetTy) && IsRetSmallStructInRegABI &&
-      (Size = getContext().getTypeSize(RetTy)) <= 64) {
+  if (isAggregateTypeForABI(RetTy) && IsRetSmallStructInRegABI && Size <= 64) {
     // System V ABI (1995), page 3-22, specified:
     // > A structure or union whose size is less than or equal to 8 bytes
     // > shall be returned in r3 and r4, as if it were first stored in the
@@ -361,6 +439,9 @@ ABIArgInfo PPC32_SVR4_ABIInfo::classifyReturnType(QualType RetTy) const {
       return ABIArgInfo::getDirect(CoerceTy);
     }
   }
+  if (isComplexInRegABI && RetTy->isAnyComplexType()) {
+    return handleComplex(RetTy, Size);
+  }
 
   return DefaultABIInfo::classifyReturnType(RetTy);
 }
@@ -372,11 +453,12 @@ Address PPC32_SVR4_ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAList,
   if (getTarget().getTriple().isOSDarwin()) {
     auto TI = getContext().getTypeInfoInChars(Ty);
     TI.Align = getParamTypeAlignment(Ty);
+    int ArgGPRs = NumArgGPRs;
 
     CharUnits SlotSize = CharUnits::fromQuantity(4);
     return emitVoidPtrVAArg(CGF, VAList, Ty,
-                            classifyArgumentType(Ty).isIndirect(), TI, SlotSize,
-                            /*AllowHigherAlign=*/true);
+                            classifyArgumentType(Ty, ArgGPRs).isIndirect(), TI,
+                            SlotSize, /*AllowHigherAlign=*/true);
   }
 
   const unsigned OverflowLimit = 8;
@@ -974,11 +1056,15 @@ CodeGen::createAIXTargetCodeGenInfo(CodeGenModule &CGM, bool Is64Bit) {
 }
 
 std::unique_ptr<TargetCodeGenInfo>
-CodeGen::createPPC32TargetCodeGenInfo(CodeGenModule &CGM, bool SoftFloatABI) {
+CodeGen::createPPC32TargetCodeGenInfo(CodeGenModule &CGM, bool SoftFloatABI,
+                                      unsigned RLen) {
   bool RetSmallStructInRegABI = PPC32TargetCodeGenInfo::isStructReturnInRegABI(
       CGM.getTriple(), CGM.getCodeGenOpts());
+  bool isComplexInRegABI = (CGM.getCodeGenOpts().getComplexInRegABI() ==
+                            CodeGenOptions::CMPLX_OnGPR);
   return std::make_unique<PPC32TargetCodeGenInfo>(CGM.getTypes(), SoftFloatABI,
-                                                  RetSmallStructInRegABI);
+                                                  RetSmallStructInRegABI, RLen,
+                                                  isComplexInRegABI);
 }
 
 std::unique_ptr<TargetCodeGenInfo>

clang/lib/Driver/ToolChains/Clang.cpp

@@ -5470,6 +5470,15 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_fcomplex_ppc_gnu_abi)) {
+    if (!TC.getTriple().isPPC32() || !TC.getTriple().isOSBinFormatELF()) {
+      D.Diag(diag::err_drv_unsupported_opt_for_target)
+          << A->getSpelling() << RawTriple.str();
+    } else {
+      CmdArgs.push_back("-fcomplex-ppc-gnu-abi");
+    }
+  }
+
   if (Args.hasFlag(options::OPT_mrtd, options::OPT_mno_rtd, false)) {
     if (Triple.getArch() == llvm::Triple::m68k)
       CmdArgs.push_back("-fdefault-calling-conv=rtdcall");

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1640,6 +1640,10 @@ void CompilerInvocationBase::GenerateCodeGenArgs(const CodeGenOptions &Opts,
     GenerateArg(Consumer, Opt);
   }
 
+  if (T.isPPC32() && Opts.ComplexInRegABI == CodeGenOptions::CMPLX_OnGPR) {
+    GenerateArg(Consumer, OPT_fcomplex_ppc_gnu_abi);
+  }
+
   if (Opts.EnableAIXExtendedAltivecABI)
     GenerateArg(Consumer, OPT_mabi_EQ_vec_extabi);
 
@@ -2034,6 +2038,10 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
     }
   }
 
+  if (Args.getLastArg(OPT_fcomplex_ppc_gnu_abi)) {
+    Opts.setComplexInRegABI(CodeGenOptions::CMPLX_OnGPR);
+  }
+
   if (Arg *A = Args.getLastArg(OPT_mxcoff_roptr)) {
     if (!T.isOSAIX())
       Diags.Report(diag::err_drv_unsupported_opt_for_target)