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   class SwiftABIInfo;
37 
38   // FIXME: All of this stuff should be part of the target interface
39   // somehow. It is currently here because it is not clear how to factor
40   // the targets to support this, since the Targets currently live in a
41   // layer below types n'stuff.
42 
43 
44   /// ABIInfo - Target specific hooks for defining how a type should be
45   /// passed or returned from functions.
46   class ABIInfo {
47   public:
48     CodeGen::CodeGenTypes &CGT;
49   protected:
50     llvm::CallingConv::ID RuntimeCC;
51   public:
52     ABIInfo(CodeGen::CodeGenTypes &cgt)
53         : CGT(cgt), RuntimeCC(llvm::CallingConv::C) {}
54 
55     virtual ~ABIInfo();
56 
57     virtual bool supportsSwift() const { return false; }
58 
59     virtual bool allowBFloatArgsAndRet() const { return false; }
60 
61     CodeGen::CGCXXABI &getCXXABI() const;
62     ASTContext &getContext() const;
63     llvm::LLVMContext &getVMContext() const;
64     const llvm::DataLayout &getDataLayout() const;
65     const TargetInfo &getTarget() const;
66     const CodeGenOptions &getCodeGenOpts() const;
67 
68     /// Return the calling convention to use for system runtime
69     /// functions.
70     llvm::CallingConv::ID getRuntimeCC() const {
71       return RuntimeCC;
72     }
73 
74     virtual void computeInfo(CodeGen::CGFunctionInfo &FI) const = 0;
75 
76     /// EmitVAArg - Emit the target dependent code to load a value of
77     /// \arg Ty from the va_list pointed to by \arg VAListAddr.
78 
79     // FIXME: This is a gaping layering violation if we wanted to drop
80     // the ABI information any lower than CodeGen. Of course, for
81     // VAArg handling it has to be at this level; there is no way to
82     // abstract this out.
83     virtual CodeGen::Address EmitVAArg(CodeGen::CodeGenFunction &CGF,
84                                        CodeGen::Address VAListAddr,
85                                        QualType Ty) const = 0;
86 
87     bool isAndroid() const;
88 
89     /// Emit the target dependent code to load a value of
90     /// \arg Ty from the \c __builtin_ms_va_list pointed to by \arg VAListAddr.
91     virtual CodeGen::Address EmitMSVAArg(CodeGen::CodeGenFunction &CGF,
92                                          CodeGen::Address VAListAddr,
93                                          QualType Ty) const;
94 
95     virtual bool isHomogeneousAggregateBaseType(QualType Ty) const;
96 
97     virtual bool isHomogeneousAggregateSmallEnough(const Type *Base,
98                                                    uint64_t Members) const;
99     virtual bool isZeroLengthBitfieldPermittedInHomogeneousAggregate() const;
100 
101     bool isHomogeneousAggregate(QualType Ty, const Type *&Base,
102                                 uint64_t &Members) const;
103 
104     // Implement the Type::IsPromotableIntegerType for ABI specific needs. The
105     // only difference is that this considers bit-precise integer types as well.
106     bool isPromotableIntegerTypeForABI(QualType Ty) const;
107 
108     /// A convenience method to return an indirect ABIArgInfo with an
109     /// expected alignment equal to the ABI alignment of the given type.
110     CodeGen::ABIArgInfo
111     getNaturalAlignIndirect(QualType Ty, bool ByVal = true,
112                             bool Realign = false,
113                             llvm::Type *Padding = nullptr) const;
114 
115     CodeGen::ABIArgInfo
116     getNaturalAlignIndirectInReg(QualType Ty, bool Realign = false) const;
117 
118 
119   };
120 
121   /// A refining implementation of ABIInfo for targets that support swiftcall.
122   ///
123   /// If we find ourselves wanting multiple such refinements, they'll probably
124   /// be independent refinements, and we should probably find another way
125   /// to do it than simple inheritance.
126   class SwiftABIInfo : public ABIInfo {
127   public:
128     SwiftABIInfo(CodeGen::CodeGenTypes &cgt) : ABIInfo(cgt) {}
129 
130     bool supportsSwift() const final { return true; }
131 
132     virtual bool shouldPassIndirectlyForSwift(ArrayRef<llvm::Type*> types,
133                                               bool asReturnValue) const = 0;
134 
135     virtual bool isLegalVectorTypeForSwift(CharUnits totalSize,
136                                            llvm::Type *eltTy,
137                                            unsigned elts) const;
138 
139     virtual bool isSwiftErrorInRegister() const = 0;
140 
141     static bool classof(const ABIInfo *info) {
142       return info->supportsSwift();
143     }
144   };
145 }  // end namespace CodeGen
146 }  // end namespace clang
147 
148 #endif
149