1 //===- llvm/CallingConv.h - LLVM Calling Conventions ------------*- 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 defines LLVM's set of calling conventions.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_IR_CALLINGCONV_H
14 #define LLVM_IR_CALLINGCONV_H
15 
16 namespace llvm {
17 
18 /// CallingConv Namespace - This namespace contains an enum with a value for
19 /// the well-known calling conventions.
20 ///
21 namespace CallingConv {
22 
23   /// LLVM IR allows to use arbitrary numbers as calling convention identifiers.
24   using ID = unsigned;
25 
26   /// A set of enums which specify the assigned numeric values for known llvm
27   /// calling conventions.
28   /// LLVM Calling Convention Representation
29   enum {
30     /// C - The default llvm calling convention, compatible with C.  This
31     /// convention is the only calling convention that supports varargs calls.
32     /// As with typical C calling conventions, the callee/caller have to
33     /// tolerate certain amounts of prototype mismatch.
34     C = 0,
35 
36     // Generic LLVM calling conventions.  None of these calling conventions
37     // support varargs calls, and all assume that the caller and callee
38     // prototype exactly match.
39 
40     /// Fast - This calling convention attempts to make calls as fast as
41     /// possible (e.g. by passing things in registers).
42     Fast = 8,
43 
44     // Cold - This calling convention attempts to make code in the caller as
45     // efficient as possible under the assumption that the call is not commonly
46     // executed.  As such, these calls often preserve all registers so that the
47     // call does not break any live ranges in the caller side.
48     Cold = 9,
49 
50     // GHC - Calling convention used by the Glasgow Haskell Compiler (GHC).
51     GHC = 10,
52 
53     // HiPE - Calling convention used by the High-Performance Erlang Compiler
54     // (HiPE).
55     HiPE = 11,
56 
57     // WebKit JS - Calling convention for stack based JavaScript calls
58     WebKit_JS = 12,
59 
60     // AnyReg - Calling convention for dynamic register based calls (e.g.
61     // stackmap and patchpoint intrinsics).
62     AnyReg = 13,
63 
64     // PreserveMost - Calling convention for runtime calls that preserves most
65     // registers.
66     PreserveMost = 14,
67 
68     // PreserveAll - Calling convention for runtime calls that preserves
69     // (almost) all registers.
70     PreserveAll = 15,
71 
72     // Swift - Calling convention for Swift.
73     Swift = 16,
74 
75     // CXX_FAST_TLS - Calling convention for access functions.
76     CXX_FAST_TLS = 17,
77 
78     /// Tail - This calling convention attemps to make calls as fast as
79     /// possible while guaranteeing that tail call optimization can always
80     /// be performed.
81     Tail = 18,
82 
83     /// Special calling convention on Windows for calling the Control
84     /// Guard Check ICall funtion. The function takes exactly one argument
85     /// (address of the target function) passed in the first argument register,
86     /// and has no return value. All register values are preserved.
87     CFGuard_Check = 19,
88 
89     /// SwiftTail - This follows the Swift calling convention in how arguments
90     /// are passed but guarantees tail calls will be made by making the callee
91     /// clean up their stack.
92     SwiftTail = 20,
93 
94     // Target - This is the start of the target-specific calling conventions,
95     // e.g. fastcall and thiscall on X86.
96     FirstTargetCC = 64,
97 
98     /// X86_StdCall - stdcall is the calling conventions mostly used by the
99     /// Win32 API. It is basically the same as the C convention with the
100     /// difference in that the callee is responsible for popping the arguments
101     /// from the stack.
102     X86_StdCall = 64,
103 
104     /// X86_FastCall - 'fast' analog of X86_StdCall. Passes first two arguments
105     /// in ECX:EDX registers, others - via stack. Callee is responsible for
106     /// stack cleaning.
107     X86_FastCall = 65,
108 
109     /// ARM_APCS - ARM Procedure Calling Standard calling convention (obsolete,
110     /// but still used on some targets).
111     ARM_APCS = 66,
112 
113     /// ARM_AAPCS - ARM Architecture Procedure Calling Standard calling
114     /// convention (aka EABI). Soft float variant.
115     ARM_AAPCS = 67,
116 
117     /// ARM_AAPCS_VFP - Same as ARM_AAPCS, but uses hard floating point ABI.
118     ARM_AAPCS_VFP = 68,
119 
120     /// MSP430_INTR - Calling convention used for MSP430 interrupt routines.
121     MSP430_INTR = 69,
122 
123     /// X86_ThisCall - Similar to X86_StdCall. Passes first argument in ECX,
124     /// others via stack. Callee is responsible for stack cleaning. MSVC uses
125     /// this by default for methods in its ABI.
126     X86_ThisCall = 70,
127 
128     /// PTX_Kernel - Call to a PTX kernel.
129     /// Passes all arguments in parameter space.
130     PTX_Kernel = 71,
131 
132     /// PTX_Device - Call to a PTX device function.
133     /// Passes all arguments in register or parameter space.
134     PTX_Device = 72,
135 
136     /// SPIR_FUNC - Calling convention for SPIR non-kernel device functions.
137     /// No lowering or expansion of arguments.
138     /// Structures are passed as a pointer to a struct with the byval attribute.
139     /// Functions can only call SPIR_FUNC and SPIR_KERNEL functions.
140     /// Functions can only have zero or one return values.
141     /// Variable arguments are not allowed, except for printf.
142     /// How arguments/return values are lowered are not specified.
143     /// Functions are only visible to the devices.
144     SPIR_FUNC = 75,
145 
146     /// SPIR_KERNEL - Calling convention for SPIR kernel functions.
147     /// Inherits the restrictions of SPIR_FUNC, except
148     /// Cannot have non-void return values.
149     /// Cannot have variable arguments.
150     /// Can also be called by the host.
151     /// Is externally visible.
152     SPIR_KERNEL = 76,
153 
154     /// Intel_OCL_BI - Calling conventions for Intel OpenCL built-ins
155     Intel_OCL_BI = 77,
156 
157     /// The C convention as specified in the x86-64 supplement to the
158     /// System V ABI, used on most non-Windows systems.
159     X86_64_SysV = 78,
160 
161     /// The C convention as implemented on Windows/x86-64 and
162     /// AArch64. This convention differs from the more common
163     /// \c X86_64_SysV convention in a number of ways, most notably in
164     /// that XMM registers used to pass arguments are shadowed by GPRs,
165     /// and vice versa.
166     /// On AArch64, this is identical to the normal C (AAPCS) calling
167     /// convention for normal functions, but floats are passed in integer
168     /// registers to variadic functions.
169     Win64 = 79,
170 
171     /// MSVC calling convention that passes vectors and vector aggregates
172     /// in SSE registers.
173     X86_VectorCall = 80,
174 
175     /// Calling convention used by HipHop Virtual Machine (HHVM) to
176     /// perform calls to and from translation cache, and for calling PHP
177     /// functions.
178     /// HHVM calling convention supports tail/sibling call elimination.
179     HHVM = 81,
180 
181     /// HHVM calling convention for invoking C/C++ helpers.
182     HHVM_C = 82,
183 
184     /// X86_INTR - x86 hardware interrupt context. Callee may take one or two
185     /// parameters, where the 1st represents a pointer to hardware context frame
186     /// and the 2nd represents hardware error code, the presence of the later
187     /// depends on the interrupt vector taken. Valid for both 32- and 64-bit
188     /// subtargets.
189     X86_INTR = 83,
190 
191     /// Used for AVR interrupt routines.
192     AVR_INTR = 84,
193 
194     /// Calling convention used for AVR signal routines.
195     AVR_SIGNAL = 85,
196 
197     /// Calling convention used for special AVR rtlib functions
198     /// which have an "optimized" convention to preserve registers.
199     AVR_BUILTIN = 86,
200 
201     /// Calling convention used for Mesa vertex shaders, or AMDPAL last shader
202     /// stage before rasterization (vertex shader if tessellation and geometry
203     /// are not in use, or otherwise copy shader if one is needed).
204     AMDGPU_VS = 87,
205 
206     /// Calling convention used for Mesa/AMDPAL geometry shaders.
207     AMDGPU_GS = 88,
208 
209     /// Calling convention used for Mesa/AMDPAL pixel shaders.
210     AMDGPU_PS = 89,
211 
212     /// Calling convention used for Mesa/AMDPAL compute shaders.
213     AMDGPU_CS = 90,
214 
215     /// Calling convention for AMDGPU code object kernels.
216     AMDGPU_KERNEL = 91,
217 
218     /// Register calling convention used for parameters transfer optimization
219     X86_RegCall = 92,
220 
221     /// Calling convention used for Mesa/AMDPAL hull shaders (= tessellation
222     /// control shaders).
223     AMDGPU_HS = 93,
224 
225     /// Calling convention used for special MSP430 rtlib functions
226     /// which have an "optimized" convention using additional registers.
227     MSP430_BUILTIN = 94,
228 
229     /// Calling convention used for AMDPAL vertex shader if tessellation is in
230     /// use.
231     AMDGPU_LS = 95,
232 
233     /// Calling convention used for AMDPAL shader stage before geometry shader
234     /// if geometry is in use. So either the domain (= tessellation evaluation)
235     /// shader if tessellation is in use, or otherwise the vertex shader.
236     AMDGPU_ES = 96,
237 
238     // Calling convention between AArch64 Advanced SIMD functions
239     AArch64_VectorCall = 97,
240 
241     /// Calling convention between AArch64 SVE functions
242     AArch64_SVE_VectorCall = 98,
243 
244     /// Calling convention for emscripten __invoke_* functions. The first
245     /// argument is required to be the function ptr being indirectly called.
246     /// The remainder matches the regular calling convention.
247     WASM_EmscriptenInvoke = 99,
248 
249     /// Calling convention used for AMD graphics targets.
250     AMDGPU_Gfx = 100,
251 
252     /// M68k_INTR - Calling convention used for M68k interrupt routines.
253     M68k_INTR = 101,
254 
255     /// The highest possible calling convention ID. Must be some 2^k - 1.
256     MaxID = 1023
257   };
258 
259 } // end namespace CallingConv
260 
261 } // end namespace llvm
262 
263 #endif // LLVM_IR_CALLINGCONV_H
264