1 //===-- llvm/Support/CodeGen.h - CodeGen Concepts ---------------*- 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 // This file define some types which define code generation concepts. For
10 // example, relocation model.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_SUPPORT_CODEGEN_H
15 #define LLVM_SUPPORT_CODEGEN_H
16 
17 #include <cstdint>
18 #include <optional>
19 
20 namespace llvm {
21 
22   // Relocation model types.
23   namespace Reloc {
24     // Cannot be named PIC due to collision with -DPIC
25     enum Model { Static, PIC_, DynamicNoPIC, ROPI, RWPI, ROPI_RWPI };
26   }
27 
28   // Code model types.
29   namespace CodeModel {
30     // Sync changes with CodeGenCWrappers.h.
31     enum Model { Tiny, Small, Kernel, Medium, Large };
32   }
33 
34   namespace PICLevel {
35     // This is used to map -fpic/-fPIC.
36     enum Level { NotPIC=0, SmallPIC=1, BigPIC=2 };
37   }
38 
39   namespace PIELevel {
40     enum Level { Default=0, Small=1, Large=2 };
41   }
42 
43   // TLS models.
44   namespace TLSModel {
45     enum Model {
46       GeneralDynamic,
47       LocalDynamic,
48       InitialExec,
49       LocalExec
50     };
51   }
52 
53   namespace CodeGenOpt {
54   /// Type for the unique integer IDs of code generation optimization levels.
55   using IDType = int;
56   /// Code generation optimization level.
57   enum Level : IDType {
58     None = 0,      ///< -O0
59     Less = 1,      ///< -O1
60     Default = 2,   ///< -O2, -Os
61     Aggressive = 3 ///< -O3
62   };
63   /// Get the \c Level identified by the integer \p ID.
64   ///
65   /// Returns std::nullopt if \p ID is invalid.
66   inline std::optional<Level> getLevel(IDType ID) {
67     if (ID < 0 || ID > 3)
68       return std::nullopt;
69     return static_cast<Level>(ID);
70   }
71   /// Parse \p C as a single digit integer ID and get matching \c Level.
72   ///
73   /// Returns std::nullopt if the input is not a valid digit or not a valid ID.
74   inline std::optional<Level> parseLevel(char C) {
75     if (C < '0')
76       return std::nullopt;
77     return getLevel(static_cast<IDType>(C - '0'));
78   }
79   } // namespace CodeGenOpt
80 
81   /// These enums are meant to be passed into addPassesToEmitFile to indicate
82   /// what type of file to emit, and returned by it to indicate what type of
83   /// file could actually be made.
84   enum CodeGenFileType {
85     CGFT_AssemblyFile,
86     CGFT_ObjectFile,
87     CGFT_Null         // Do not emit any output.
88   };
89 
90   // Specify what functions should keep the frame pointer.
91   enum class FramePointerKind { None, NonLeaf, All };
92 
93   // Specify what type of zeroing callee-used registers.
94   namespace ZeroCallUsedRegs {
95   const unsigned ONLY_USED = 1U << 1;
96   const unsigned ONLY_GPR = 1U << 2;
97   const unsigned ONLY_ARG = 1U << 3;
98 
99   enum class ZeroCallUsedRegsKind : unsigned int {
100     // Don't zero any call-used regs.
101     Skip = 1U << 0,
102     // Only zeros call-used GPRs used in the fn and pass args.
103     UsedGPRArg = ONLY_USED | ONLY_GPR | ONLY_ARG,
104     // Only zeros call-used GPRs used in the fn.
105     UsedGPR = ONLY_USED | ONLY_GPR,
106     // Only zeros call-used regs used in the fn and pass args.
107     UsedArg = ONLY_USED | ONLY_ARG,
108     // Only zeros call-used regs used in the fn.
109     Used = ONLY_USED,
110     // Zeros all call-used GPRs that pass args.
111     AllGPRArg = ONLY_GPR | ONLY_ARG,
112     // Zeros all call-used GPRs.
113     AllGPR = ONLY_GPR,
114     // Zeros all call-used regs that pass args.
115     AllArg = ONLY_ARG,
116     // Zeros all call-used regs.
117     All = 0,
118   };
119   } // namespace ZeroCallUsedRegs
120 
121   enum class UWTableKind {
122     None = 0,  ///< No unwind table requested
123     Sync = 1,  ///< "Synchronous" unwind tables
124     Async = 2, ///< "Asynchronous" unwind tables (instr precise)
125     Default = 2,
126   };
127 
128   enum class FunctionReturnThunksKind : unsigned int {
129     Keep = 0,    ///< No function return thunk.
130     Extern = 1,  ///< Replace returns with jump to thunk, don't emit thunk.
131     Invalid = 2, ///< Not used.
132   };
133 
134   } // namespace llvm
135 
136 #endif
137