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 namespace swiftcall {
39   class SwiftAggLowering;
40 }
41 
42   // FIXME: All of this stuff should be part of the target interface
43   // somehow. It is currently here because it is not clear how to factor
44   // the targets to support this, since the Targets currently live in a
45   // layer below types n'stuff.
46 
47 
48   /// ABIInfo - Target specific hooks for defining how a type should be
49   /// passed or returned from functions.
50   class ABIInfo {
51   public:
52     CodeGen::CodeGenTypes &CGT;
53   protected:
54     llvm::CallingConv::ID RuntimeCC;
55   public:
56     ABIInfo(CodeGen::CodeGenTypes &cgt)
57         : CGT(cgt), RuntimeCC(llvm::CallingConv::C) {}
58 
59     virtual ~ABIInfo();
60 
61     virtual bool supportsSwift() const { return false; }
62 
63     virtual bool allowBFloatArgsAndRet() const { return false; }
64 
65     CodeGen::CGCXXABI &getCXXABI() const;
66     ASTContext &getContext() const;
67     llvm::LLVMContext &getVMContext() const;
68     const llvm::DataLayout &getDataLayout() const;
69     const TargetInfo &getTarget() const;
70     const CodeGenOptions &getCodeGenOpts() const;
71 
72     /// Return the calling convention to use for system runtime
73     /// functions.
74     llvm::CallingConv::ID getRuntimeCC() const {
75       return RuntimeCC;
76     }
77 
78     virtual void computeInfo(CodeGen::CGFunctionInfo &FI) const = 0;
79 
80     /// EmitVAArg - Emit the target dependent code to load a value of
81     /// \arg Ty from the va_list pointed to by \arg VAListAddr.
82 
83     // FIXME: This is a gaping layering violation if we wanted to drop
84     // the ABI information any lower than CodeGen. Of course, for
85     // VAArg handling it has to be at this level; there is no way to
86     // abstract this out.
87     virtual CodeGen::Address EmitVAArg(CodeGen::CodeGenFunction &CGF,
88                                        CodeGen::Address VAListAddr,
89                                        QualType Ty) const = 0;
90 
91     bool isAndroid() const;
92 
93     /// Emit the target dependent code to load a value of
94     /// \arg Ty from the \c __builtin_ms_va_list pointed to by \arg VAListAddr.
95     virtual CodeGen::Address EmitMSVAArg(CodeGen::CodeGenFunction &CGF,
96                                          CodeGen::Address VAListAddr,
97                                          QualType Ty) const;
98 
99     virtual bool isHomogeneousAggregateBaseType(QualType Ty) const;
100 
101     virtual bool isHomogeneousAggregateSmallEnough(const Type *Base,
102                                                    uint64_t Members) const;
103 
104     bool isHomogeneousAggregate(QualType Ty, const Type *&Base,
105                                 uint64_t &Members) const;
106 
107     // Implement the Type::IsPromotableIntegerType for ABI specific needs. The
108     // only difference is that this considers _ExtInt as well.
109     bool isPromotableIntegerTypeForABI(QualType Ty) const;
110 
111     /// A convenience method to return an indirect ABIArgInfo with an
112     /// expected alignment equal to the ABI alignment of the given type.
113     CodeGen::ABIArgInfo
114     getNaturalAlignIndirect(QualType Ty, bool ByVal = true,
115                             bool Realign = false,
116                             llvm::Type *Padding = nullptr) const;
117 
118     CodeGen::ABIArgInfo
119     getNaturalAlignIndirectInReg(QualType Ty, bool Realign = false) const;
120 
121 
122   };
123 
124   /// A refining implementation of ABIInfo for targets that support swiftcall.
125   ///
126   /// If we find ourselves wanting multiple such refinements, they'll probably
127   /// be independent refinements, and we should probably find another way
128   /// to do it than simple inheritance.
129   class SwiftABIInfo : public ABIInfo {
130   public:
131     SwiftABIInfo(CodeGen::CodeGenTypes &cgt) : ABIInfo(cgt) {}
132 
133     bool supportsSwift() const final override { return true; }
134 
135     virtual bool shouldPassIndirectlyForSwift(ArrayRef<llvm::Type*> types,
136                                               bool asReturnValue) const = 0;
137 
138     virtual bool isLegalVectorTypeForSwift(CharUnits totalSize,
139                                            llvm::Type *eltTy,
140                                            unsigned elts) const;
141 
142     virtual bool isSwiftErrorInRegister() const = 0;
143 
144     static bool classof(const ABIInfo *info) {
145       return info->supportsSwift();
146     }
147   };
148 }  // end namespace CodeGen
149 }  // end namespace clang
150 
151 #endif
152