clang/lib/CodeGen/ABIInfo.h

   1 //===----- ABIInfo.h - ABI information access & encapsulation ---*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_CLANG_LIB_CODEGEN_ABIINFO_H
  10 #define LLVM_CLANG_LIB_CODEGEN_ABIINFO_H
  11
  12 #include "clang/AST/CharUnits.h"
  13 #include "clang/AST/Type.h"
  14 #include "llvm/IR/CallingConv.h"
  15 #include "llvm/IR/Type.h"
  16
  17 namespace llvm {
  18   class Value;
  19   class LLVMContext;
  20   class DataLayout;
  21   class Type;
  22 }
  23
  24 namespace clang {
  25   class ASTContext;
  26   class CodeGenOptions;
  27   class TargetInfo;
  28
  29 namespace CodeGen {
  30   class ABIArgInfo;
  31   class Address;
  32   class CGCXXABI;
  33   class CGFunctionInfo;
  34   class CodeGenFunction;
  35   class CodeGenTypes;
  36
  37   // FIXME: All of this stuff should be part of the target interface
  38   // somehow. It is currently here because it is not clear how to factor
  39   // the targets to support this, since the Targets currently live in a
  40   // layer below types n'stuff.
  41
  42
  43   /// ABIInfo - Target specific hooks for defining how a type should be
  44   /// passed or returned from functions.
  45   class ABIInfo {
  46   protected:
  47     CodeGen::CodeGenTypes &CGT;
  48     llvm::CallingConv::ID RuntimeCC;
  49   public:
  50     ABIInfo(CodeGen::CodeGenTypes &cgt)
  51         : CGT(cgt), RuntimeCC(llvm::CallingConv::C) {}
  52
  53     virtual ~ABIInfo();
  54
  55     virtual bool allowBFloatArgsAndRet() const { return false; }
  56
  57     CodeGen::CGCXXABI &getCXXABI() const;
  58     ASTContext &getContext() const;
  59     llvm::LLVMContext &getVMContext() const;
  60     const llvm::DataLayout &getDataLayout() const;
  61     const TargetInfo &getTarget() const;
  62     const CodeGenOptions &getCodeGenOpts() const;
  63
  64     /// Return the calling convention to use for system runtime
  65     /// functions.
  66     llvm::CallingConv::ID getRuntimeCC() const {
  67       return RuntimeCC;
  68     }
  69
  70     virtual void computeInfo(CodeGen::CGFunctionInfo &FI) const = 0;
  71
  72     /// EmitVAArg - Emit the target dependent code to load a value of
  73     /// \arg Ty from the va_list pointed to by \arg VAListAddr.
  74
  75     // FIXME: This is a gaping layering violation if we wanted to drop
  76     // the ABI information any lower than CodeGen. Of course, for
  77     // VAArg handling it has to be at this level; there is no way to
  78     // abstract this out.
  79     virtual CodeGen::Address EmitVAArg(CodeGen::CodeGenFunction &CGF,
  80                                        CodeGen::Address VAListAddr,
  81                                        QualType Ty) const = 0;
  82
  83     bool isAndroid() const;
  84
  85     /// Emit the target dependent code to load a value of
  86     /// \arg Ty from the \c __builtin_ms_va_list pointed to by \arg VAListAddr.
  87     virtual CodeGen::Address EmitMSVAArg(CodeGen::CodeGenFunction &CGF,
  88                                          CodeGen::Address VAListAddr,
  89                                          QualType Ty) const;
  90
  91     virtual bool isHomogeneousAggregateBaseType(QualType Ty) const;
  92
  93     virtual bool isHomogeneousAggregateSmallEnough(const Type *Base,
  94                                                    uint64_t Members) const;
  95     virtual bool isZeroLengthBitfieldPermittedInHomogeneousAggregate() const;
  96
  97     bool isHomogeneousAggregate(QualType Ty, const Type *&Base,
  98                                 uint64_t &Members) const;
  99
 100     // Implement the Type::IsPromotableIntegerType for ABI specific needs. The
 101     // only difference is that this considers bit-precise integer types as well.
 102     bool isPromotableIntegerTypeForABI(QualType Ty) const;
 103
 104     /// A convenience method to return an indirect ABIArgInfo with an
 105     /// expected alignment equal to the ABI alignment of the given type.
 106     CodeGen::ABIArgInfo
 107     getNaturalAlignIndirect(QualType Ty, bool ByVal = true,
 108                             bool Realign = false,
 109                             llvm::Type *Padding = nullptr) const;
 110
 111     CodeGen::ABIArgInfo
 112     getNaturalAlignIndirectInReg(QualType Ty, bool Realign = false) const;
 113   };
 114
 115   /// Target specific hooks for defining how a type should be passed or returned
 116   /// from functions with one of the Swift calling conventions.
 117   class SwiftABIInfo {
 118   protected:
 119     CodeGenTypes &CGT;
 120     bool SwiftErrorInRegister;
 121
 122   public:
 123     SwiftABIInfo(CodeGen::CodeGenTypes &CGT, bool SwiftErrorInRegister)
 124         : CGT(CGT), SwiftErrorInRegister(SwiftErrorInRegister) {}
 125
 126     virtual ~SwiftABIInfo();
 127
 128     /// Returns true if an aggregate which expands to the given type sequence
 129     /// should be passed / returned indirectly.
 130     virtual bool shouldPassIndirectly(ArrayRef<llvm::Type *> ComponentTys,
 131                                       bool AsReturnValue) const;
 132
 133     /// Returns true if the given vector type is legal from Swift's calling
 134     /// convention perspective.
 135     virtual bool isLegalVectorType(CharUnits VectorSize, llvm::Type *EltTy,
 136                                    unsigned NumElts) const;
 137
 138     /// Returns true if swifterror is lowered to a register by the target ABI.
 139     bool isSwiftErrorInRegister() const { return SwiftErrorInRegister; };
 140   };
 141 }  // end namespace CodeGen
 142 }  // end namespace clang
 143
 144 #endif