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   /// Code generation optimization level.
54   enum class CodeGenOptLevel {
55     None = 0,      ///< -O0
56     Less = 1,      ///< -O1
57     Default = 2,   ///< -O2, -Os
58     Aggressive = 3 ///< -O3
59   };
60 
61   namespace CodeGenOpt {
62   /// Get the \c Level identified by the integer \p OL.
63   ///
64   /// Returns std::nullopt if \p OL is invalid.
65   inline std::optional<CodeGenOptLevel> getLevel(int OL) {
66     if (OL < 0 || OL > 3)
67       return std::nullopt;
68     return static_cast<CodeGenOptLevel>(OL);
69   }
70   /// Parse \p C as a single digit integer and get matching \c CodeGenLevel.
71   ///
72   /// Returns std::nullopt if the input is not a valid optimization level.
73   inline std::optional<CodeGenOptLevel> parseLevel(char C) {
74     if (C < '0')
75       return std::nullopt;
76     return getLevel(static_cast<int>(C - '0'));
77   }
78   } // namespace CodeGenOpt
79 
80   /// These enums are meant to be passed into addPassesToEmitFile to indicate
81   /// what type of file to emit, and returned by it to indicate what type of
82   /// file could actually be made.
83   enum class CodeGenFileType {
84     AssemblyFile,
85     ObjectFile,
86     Null // Do not emit any output.
87   };
88 
89   // Specify what functions should keep the frame pointer.
90   enum class FramePointerKind { None, NonLeaf, All };
91 
92   // Specify what type of zeroing callee-used registers.
93   namespace ZeroCallUsedRegs {
94   const unsigned ONLY_USED = 1U << 1;
95   const unsigned ONLY_GPR = 1U << 2;
96   const unsigned ONLY_ARG = 1U << 3;
97 
98   enum class ZeroCallUsedRegsKind : unsigned int {
99     // Don't zero any call-used regs.
100     Skip = 1U << 0,
101     // Only zeros call-used GPRs used in the fn and pass args.
102     UsedGPRArg = ONLY_USED | ONLY_GPR | ONLY_ARG,
103     // Only zeros call-used GPRs used in the fn.
104     UsedGPR = ONLY_USED | ONLY_GPR,
105     // Only zeros call-used regs used in the fn and pass args.
106     UsedArg = ONLY_USED | ONLY_ARG,
107     // Only zeros call-used regs used in the fn.
108     Used = ONLY_USED,
109     // Zeros all call-used GPRs that pass args.
110     AllGPRArg = ONLY_GPR | ONLY_ARG,
111     // Zeros all call-used GPRs.
112     AllGPR = ONLY_GPR,
113     // Zeros all call-used regs that pass args.
114     AllArg = ONLY_ARG,
115     // Zeros all call-used regs.
116     All = 0,
117   };
118   } // namespace ZeroCallUsedRegs
119 
120   enum class UWTableKind {
121     None = 0,  ///< No unwind table requested
122     Sync = 1,  ///< "Synchronous" unwind tables
123     Async = 2, ///< "Asynchronous" unwind tables (instr precise)
124     Default = 2,
125   };
126 
127   enum class FunctionReturnThunksKind : unsigned int {
128     Keep = 0,    ///< No function return thunk.
129     Extern = 1,  ///< Replace returns with jump to thunk, don't emit thunk.
130     Invalid = 2, ///< Not used.
131   };
132 
133   } // namespace llvm
134 
135 #endif
136