Add SystemZ support

This patch then adds all the usual platform-specific pieces for SystemZ:
driver support, basic target info, register names and constraints,
ABI info and vararg support.  It also adds new tests to verify pre-defined
macros and inline asm, and updates a test for the minimum alignment change.

This version of the patch incorporates feedback from reviews by
Eric Christopher and John McCall.  Thanks to all reviewers!

Patch by Richard Sandiford.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181211 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 290 insertions, 0 deletions

diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index 83d1f6d8b5..32b27b3172 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -4117,6 +4117,293 @@ void NVPTXTargetCodeGenInfo::addKernelMetadata(llvm::Function *F) {
 }
 
 //===----------------------------------------------------------------------===//
+// SystemZ ABI Implementation
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+class SystemZABIInfo : public ABIInfo {
+public:
+  SystemZABIInfo(CodeGenTypes &CGT) : ABIInfo(CGT) {}
+
+  bool isPromotableIntegerType(QualType Ty) const;
+  bool isCompoundType(QualType Ty) const;
+  bool isFPArgumentType(QualType Ty) const;
+
+  ABIArgInfo classifyReturnType(QualType RetTy) const;
+  ABIArgInfo classifyArgumentType(QualType ArgTy) const;
+
+  virtual void computeInfo(CGFunctionInfo &FI) const {
+    FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
+    for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
+         it != ie; ++it)
+      it->info = classifyArgumentType(it->type);
+  }
+
+  virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
+                                 CodeGenFunction &CGF) const;
+};
+
+class SystemZTargetCodeGenInfo : public TargetCodeGenInfo {
+public:
+  SystemZTargetCodeGenInfo(CodeGenTypes &CGT)
+    : TargetCodeGenInfo(new SystemZABIInfo(CGT)) {}
+};
+
+}
+
+bool SystemZABIInfo::isPromotableIntegerType(QualType Ty) const {
+  // Treat an enum type as its underlying type.
+  if (const EnumType *EnumTy = Ty->getAs<EnumType>())
+    Ty = EnumTy->getDecl()->getIntegerType();
+
+  // Promotable integer types are required to be promoted by the ABI.
+  if (Ty->isPromotableIntegerType())
+    return true;
+
+  // 32-bit values must also be promoted.
+  if (const BuiltinType *BT = Ty->getAs<BuiltinType>())
+    switch (BT->getKind()) {
+    case BuiltinType::Int:
+    case BuiltinType::UInt:
+      return true;
+    default:
+      return false;
+    }
+  return false;
+}
+
+bool SystemZABIInfo::isCompoundType(QualType Ty) const {
+  return Ty->isAnyComplexType() || isAggregateTypeForABI(Ty);
+}
+
+bool SystemZABIInfo::isFPArgumentType(QualType Ty) const {
+  if (const BuiltinType *BT = Ty->getAs<BuiltinType>())
+    switch (BT->getKind()) {
+    case BuiltinType::Float:
+    case BuiltinType::Double:
+      return true;
+    default:
+      return false;
+    }
+
+  if (const RecordType *RT = Ty->getAsStructureType()) {
+    const RecordDecl *RD = RT->getDecl();
+    bool Found = false;
+
+    // If this is a C++ record, check the bases first.
+    if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD))
+      for (CXXRecordDecl::base_class_const_iterator I = CXXRD->bases_begin(),
+             E = CXXRD->bases_end(); I != E; ++I) {
+        QualType Base = I->getType();
+
+        // Empty bases don't affect things either way.
+        if (isEmptyRecord(getContext(), Base, true))
+          continue;
+
+        if (Found)
+          return false;
+        Found = isFPArgumentType(Base);
+        if (!Found)
+          return false;
+      }
+
+    // Check the fields.
+    for (RecordDecl::field_iterator I = RD->field_begin(),
+           E = RD->field_end(); I != E; ++I) {
+      const FieldDecl *FD = *I;
+
+      // Empty bitfields don't affect things either way.
+      // Unlike isSingleElementStruct(), empty structure and array fields
+      // do count.  So do anonymous bitfields that aren't zero-sized.
+      if (FD->isBitField() && FD->getBitWidthValue(getContext()) == 0)
+        return true;
+
+      // Unlike isSingleElementStruct(), arrays do not count.
+      // Nested isFPArgumentType structures still do though.
+      if (Found)
+        return false;
+      Found = isFPArgumentType(FD->getType());
+      if (!Found)
+        return false;
+    }
+
+    // Unlike isSingleElementStruct(), trailing padding is allowed.
+    // An 8-byte aligned struct s { float f; } is passed as a double.
+    return Found;
+  }
+
+  return false;
+}
+
+llvm::Value *SystemZABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
+                                       CodeGenFunction &CGF) const {
+  // Assume that va_list type is correct; should be pointer to LLVM type:
+  // struct {
+  //   i64 __gpr;
+  //   i64 __fpr;
+  //   i8 *__overflow_arg_area;
+  //   i8 *__reg_save_area;
+  // };
+
+  // Every argument occupies 8 bytes and is passed by preference in either
+  // GPRs or FPRs.
+  Ty = CGF.getContext().getCanonicalType(Ty);
+  ABIArgInfo AI = classifyArgumentType(Ty);
+  bool InFPRs = isFPArgumentType(Ty);
+
+  llvm::Type *APTy = llvm::PointerType::getUnqual(CGF.ConvertTypeForMem(Ty));
+  bool IsIndirect = AI.isIndirect();
+  unsigned UnpaddedBitSize;
+  if (IsIndirect) {
+    APTy = llvm::PointerType::getUnqual(APTy);
+    UnpaddedBitSize = 64;
+  } else
+    UnpaddedBitSize = getContext().getTypeSize(Ty);
+  unsigned PaddedBitSize = 64;
+  assert((UnpaddedBitSize <= PaddedBitSize) && "Invalid argument size.");
+
+  unsigned PaddedSize = PaddedBitSize / 8;
+  unsigned Padding = (PaddedBitSize - UnpaddedBitSize) / 8;
+
+  unsigned MaxRegs, RegCountField, RegSaveIndex, RegPadding;
+  if (InFPRs) {
+    MaxRegs = 4; // Maximum of 4 FPR arguments
+    RegCountField = 1; // __fpr
+    RegSaveIndex = 16; // save offset for f0
+    RegPadding = 0; // floats are passed in the high bits of an FPR
+  } else {
+    MaxRegs = 5; // Maximum of 5 GPR arguments
+    RegCountField = 0; // __gpr
+    RegSaveIndex = 2; // save offset for r2
+    RegPadding = Padding; // values are passed in the low bits of a GPR
+  }
+
+  llvm::Value *RegCountPtr =
+    CGF.Builder.CreateStructGEP(VAListAddr, RegCountField, "reg_count_ptr");
+  llvm::Value *RegCount = CGF.Builder.CreateLoad(RegCountPtr, "reg_count");
+  llvm::Type *IndexTy = RegCount->getType();
+  llvm::Value *MaxRegsV = llvm::ConstantInt::get(IndexTy, MaxRegs);
+  llvm::Value *InRegs = CGF.Builder.CreateICmpULT(RegCount, MaxRegsV,
+						  "fits_in_regs");
+
+  llvm::BasicBlock *InRegBlock = CGF.createBasicBlock("vaarg.in_reg");
+  llvm::BasicBlock *InMemBlock = CGF.createBasicBlock("vaarg.in_mem");
+  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("vaarg.end");
+  CGF.Builder.CreateCondBr(InRegs, InRegBlock, InMemBlock);
+
+  // Emit code to load the value if it was passed in registers.
+  CGF.EmitBlock(InRegBlock);
+
+  // Work out the address of an argument register.
+  llvm::Value *PaddedSizeV = llvm::ConstantInt::get(IndexTy, PaddedSize);
+  llvm::Value *ScaledRegCount =
+    CGF.Builder.CreateMul(RegCount, PaddedSizeV, "scaled_reg_count");
+  llvm::Value *RegBase =
+    llvm::ConstantInt::get(IndexTy, RegSaveIndex * PaddedSize + RegPadding);
+  llvm::Value *RegOffset =
+    CGF.Builder.CreateAdd(ScaledRegCount, RegBase, "reg_offset");
+  llvm::Value *RegSaveAreaPtr =
+    CGF.Builder.CreateStructGEP(VAListAddr, 3, "reg_save_area_ptr");
+  llvm::Value *RegSaveArea =
+    CGF.Builder.CreateLoad(RegSaveAreaPtr, "reg_save_area");
+  llvm::Value *RawRegAddr =
+    CGF.Builder.CreateGEP(RegSaveArea, RegOffset, "raw_reg_addr");
+  llvm::Value *RegAddr =
+    CGF.Builder.CreateBitCast(RawRegAddr, APTy, "reg_addr");
+
+  // Update the register count
+  llvm::Value *One = llvm::ConstantInt::get(IndexTy, 1);
+  llvm::Value *NewRegCount =
+    CGF.Builder.CreateAdd(RegCount, One, "reg_count");
+  CGF.Builder.CreateStore(NewRegCount, RegCountPtr);
+  CGF.EmitBranch(ContBlock);
+
+  // Emit code to load the value if it was passed in memory.
+  CGF.EmitBlock(InMemBlock);
+
+  // Work out the address of a stack argument.
+  llvm::Value *OverflowArgAreaPtr =
+    CGF.Builder.CreateStructGEP(VAListAddr, 2, "overflow_arg_area_ptr");
+  llvm::Value *OverflowArgArea =
+    CGF.Builder.CreateLoad(OverflowArgAreaPtr, "overflow_arg_area");
+  llvm::Value *PaddingV = llvm::ConstantInt::get(IndexTy, Padding);
+  llvm::Value *RawMemAddr =
+    CGF.Builder.CreateGEP(OverflowArgArea, PaddingV, "raw_mem_addr");
+  llvm::Value *MemAddr =
+    CGF.Builder.CreateBitCast(RawMemAddr, APTy, "mem_addr");
+
+  // Update overflow_arg_area_ptr pointer
+  llvm::Value *NewOverflowArgArea =
+    CGF.Builder.CreateGEP(OverflowArgArea, PaddedSizeV, "overflow_arg_area");
+  CGF.Builder.CreateStore(NewOverflowArgArea, OverflowArgAreaPtr);
+  CGF.EmitBranch(ContBlock);
+
+  // Return the appropriate result.
+  CGF.EmitBlock(ContBlock);
+  llvm::PHINode *ResAddr = CGF.Builder.CreatePHI(APTy, 2, "va_arg.addr");
+  ResAddr->addIncoming(RegAddr, InRegBlock);
+  ResAddr->addIncoming(MemAddr, InMemBlock);
+
+  if (IsIndirect)
+    return CGF.Builder.CreateLoad(ResAddr, "indirect_arg");
+
+  return ResAddr;
+}
+
+
+ABIArgInfo SystemZABIInfo::classifyReturnType(QualType RetTy) const {
+  if (RetTy->isVoidType())
+    return ABIArgInfo::getIgnore();
+  if (isCompoundType(RetTy) || getContext().getTypeSize(RetTy) > 64)
+    return ABIArgInfo::getIndirect(0);
+  return (isPromotableIntegerType(RetTy) ?
+          ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
+}
+
+ABIArgInfo SystemZABIInfo::classifyArgumentType(QualType Ty) const {
+  // Handle the generic C++ ABI.
+  if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, CGT))
+    return ABIArgInfo::getIndirect(0, RAA == CGCXXABI::RAA_DirectInMemory);
+
+  // Integers and enums are extended to full register width.
+  if (isPromotableIntegerType(Ty))
+    return ABIArgInfo::getExtend();
+
+  // Values that are not 1, 2, 4 or 8 bytes in size are passed indirectly.
+  uint64_t Size = getContext().getTypeSize(Ty);
+  if (Size != 8 && Size != 16 && Size != 32 && Size != 64)
+    return ABIArgInfo::getIndirect(0);
+
+  // Handle small structures.
+  if (const RecordType *RT = Ty->getAs<RecordType>()) {
+    // Structures with flexible arrays have variable length, so really
+    // fail the size test above.
+    const RecordDecl *RD = RT->getDecl();
+    if (RD->hasFlexibleArrayMember())
+      return ABIArgInfo::getIndirect(0);
+
+    // The structure is passed as an unextended integer, a float, or a double.
+    llvm::Type *PassTy;
+    if (isFPArgumentType(Ty)) {
+      assert(Size == 32 || Size == 64);
+      if (Size == 32)
+        PassTy = llvm::Type::getFloatTy(getVMContext());
+      else
+        PassTy = llvm::Type::getDoubleTy(getVMContext());
+    } else
+      PassTy = llvm::IntegerType::get(getVMContext(), Size);
+    return ABIArgInfo::getDirect(PassTy);
+  }
+
+  // Non-structure compounds are passed indirectly.
+  if (isCompoundType(Ty))
+    return ABIArgInfo::getIndirect(0);
+
+  return ABIArgInfo::getDirect(0);
+}
+
+//===----------------------------------------------------------------------===//
 // MBlaze ABI Implementation
 //===----------------------------------------------------------------------===//
 
@@ -4860,6 +5147,9 @@ const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
   case llvm::Triple::msp430:
     return *(TheTargetCodeGenInfo = new MSP430TargetCodeGenInfo(Types));
 
+  case llvm::Triple::systemz:
+    return *(TheTargetCodeGenInfo = new SystemZTargetCodeGenInfo(Types));
+
   case llvm::Triple::tce:
     return *(TheTargetCodeGenInfo = new TCETargetCodeGenInfo(Types));