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 } // namespace llvm
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 /// ABIInfo - Target specific hooks for defining how a type should be
43 /// passed or returned from functions.
44 class ABIInfo {
45 protected:
46   CodeGen::CodeGenTypes &CGT;
47   llvm::CallingConv::ID RuntimeCC;
48 
49 public:
ABIInfo(CodeGen::CodeGenTypes & cgt)50   ABIInfo(CodeGen::CodeGenTypes &cgt)
51       : CGT(cgt), RuntimeCC(llvm::CallingConv::C) {}
52 
53   virtual ~ABIInfo();
54 
allowBFloatArgsAndRet()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.
getRuntimeCC()66   llvm::CallingConv::ID getRuntimeCC() const { return RuntimeCC; }
67 
68   virtual void computeInfo(CodeGen::CGFunctionInfo &FI) const = 0;
69 
70   /// EmitVAArg - Emit the target dependent code to load a value of
71   /// \arg Ty from the va_list pointed to by \arg VAListAddr.
72 
73   // FIXME: This is a gaping layering violation if we wanted to drop
74   // the ABI information any lower than CodeGen. Of course, for
75   // VAArg handling it has to be at this level; there is no way to
76   // abstract this out.
77   virtual CodeGen::Address EmitVAArg(CodeGen::CodeGenFunction &CGF,
78                                      CodeGen::Address VAListAddr,
79                                      QualType Ty) const = 0;
80 
81   bool isAndroid() const;
82   bool isOHOSFamily() const;
83 
84   /// Emit the target dependent code to load a value of
85   /// \arg Ty from the \c __builtin_ms_va_list pointed to by \arg VAListAddr.
86   virtual CodeGen::Address EmitMSVAArg(CodeGen::CodeGenFunction &CGF,
87                                        CodeGen::Address VAListAddr,
88                                        QualType Ty) const;
89 
90   virtual bool isHomogeneousAggregateBaseType(QualType Ty) const;
91 
92   virtual bool isHomogeneousAggregateSmallEnough(const Type *Base,
93                                                  uint64_t Members) const;
94   virtual bool isZeroLengthBitfieldPermittedInHomogeneousAggregate() const;
95 
96   /// isHomogeneousAggregate - Return true if a type is an ELFv2 homogeneous
97   /// aggregate.  Base is set to the base element type, and Members is set
98   /// to the number of base elements.
99   bool isHomogeneousAggregate(QualType Ty, const Type *&Base,
100                               uint64_t &Members) const;
101 
102   // Implement the Type::IsPromotableIntegerType for ABI specific needs. The
103   // only difference is that this considers bit-precise integer types as well.
104   bool isPromotableIntegerTypeForABI(QualType Ty) const;
105 
106   /// A convenience method to return an indirect ABIArgInfo with an
107   /// expected alignment equal to the ABI alignment of the given type.
108   CodeGen::ABIArgInfo
109   getNaturalAlignIndirect(QualType Ty, bool ByVal = true, bool Realign = false,
110                           llvm::Type *Padding = nullptr) const;
111 
112   CodeGen::ABIArgInfo getNaturalAlignIndirectInReg(QualType Ty,
113                                                    bool Realign = false) const;
114 };
115 
116 /// Target specific hooks for defining how a type should be passed or returned
117 /// from functions with one of the Swift calling conventions.
118 class SwiftABIInfo {
119 protected:
120   CodeGenTypes &CGT;
121   bool SwiftErrorInRegister;
122 
123   bool occupiesMoreThan(ArrayRef<llvm::Type *> scalarTypes,
124                         unsigned maxAllRegisters) const;
125 
126 public:
SwiftABIInfo(CodeGen::CodeGenTypes & CGT,bool SwiftErrorInRegister)127   SwiftABIInfo(CodeGen::CodeGenTypes &CGT, bool SwiftErrorInRegister)
128       : CGT(CGT), SwiftErrorInRegister(SwiftErrorInRegister) {}
129 
130   virtual ~SwiftABIInfo();
131 
132   /// Returns true if an aggregate which expands to the given type sequence
133   /// should be passed / returned indirectly.
134   virtual bool shouldPassIndirectly(ArrayRef<llvm::Type *> ComponentTys,
135                                     bool AsReturnValue) const;
136 
137   /// Returns true if the given vector type is legal from Swift's calling
138   /// convention perspective.
139   virtual bool isLegalVectorType(CharUnits VectorSize, llvm::Type *EltTy,
140                                  unsigned NumElts) const;
141 
142   /// Returns true if swifterror is lowered to a register by the target ABI.
isSwiftErrorInRegister()143   bool isSwiftErrorInRegister() const { return SwiftErrorInRegister; };
144 };
145 } // end namespace CodeGen
146 } // end namespace clang
147 
148 #endif
149