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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     // Target - This is the start of the target-specific calling conventions,
90     // e.g. fastcall and thiscall on X86.
91     FirstTargetCC = 64,
92 
93     /// X86_StdCall - stdcall is the calling conventions mostly used by the
94     /// Win32 API. It is basically the same as the C convention with the
95     /// difference in that the callee is responsible for popping the arguments
96     /// from the stack.
97     X86_StdCall = 64,
98 
99     /// X86_FastCall - 'fast' analog of X86_StdCall. Passes first two arguments
100     /// in ECX:EDX registers, others - via stack. Callee is responsible for
101     /// stack cleaning.
102     X86_FastCall = 65,
103 
104     /// ARM_APCS - ARM Procedure Calling Standard calling convention (obsolete,
105     /// but still used on some targets).
106     ARM_APCS = 66,
107 
108     /// ARM_AAPCS - ARM Architecture Procedure Calling Standard calling
109     /// convention (aka EABI). Soft float variant.
110     ARM_AAPCS = 67,
111 
112     /// ARM_AAPCS_VFP - Same as ARM_AAPCS, but uses hard floating point ABI.
113     ARM_AAPCS_VFP = 68,
114 
115     /// MSP430_INTR - Calling convention used for MSP430 interrupt routines.
116     MSP430_INTR = 69,
117 
118     /// X86_ThisCall - Similar to X86_StdCall. Passes first argument in ECX,
119     /// others via stack. Callee is responsible for stack cleaning. MSVC uses
120     /// this by default for methods in its ABI.
121     X86_ThisCall = 70,
122 
123     /// PTX_Kernel - Call to a PTX kernel.
124     /// Passes all arguments in parameter space.
125     PTX_Kernel = 71,
126 
127     /// PTX_Device - Call to a PTX device function.
128     /// Passes all arguments in register or parameter space.
129     PTX_Device = 72,
130 
131     /// SPIR_FUNC - Calling convention for SPIR non-kernel device functions.
132     /// No lowering or expansion of arguments.
133     /// Structures are passed as a pointer to a struct with the byval attribute.
134     /// Functions can only call SPIR_FUNC and SPIR_KERNEL functions.
135     /// Functions can only have zero or one return values.
136     /// Variable arguments are not allowed, except for printf.
137     /// How arguments/return values are lowered are not specified.
138     /// Functions are only visible to the devices.
139     SPIR_FUNC = 75,
140 
141     /// SPIR_KERNEL - Calling convention for SPIR kernel functions.
142     /// Inherits the restrictions of SPIR_FUNC, except
143     /// Cannot have non-void return values.
144     /// Cannot have variable arguments.
145     /// Can also be called by the host.
146     /// Is externally visible.
147     SPIR_KERNEL = 76,
148 
149     /// Intel_OCL_BI - Calling conventions for Intel OpenCL built-ins
150     Intel_OCL_BI = 77,
151 
152     /// The C convention as specified in the x86-64 supplement to the
153     /// System V ABI, used on most non-Windows systems.
154     X86_64_SysV = 78,
155 
156     /// The C convention as implemented on Windows/x86-64 and
157     /// AArch64. This convention differs from the more common
158     /// \c X86_64_SysV convention in a number of ways, most notably in
159     /// that XMM registers used to pass arguments are shadowed by GPRs,
160     /// and vice versa.
161     /// On AArch64, this is identical to the normal C (AAPCS) calling
162     /// convention for normal functions, but floats are passed in integer
163     /// registers to variadic functions.
164     Win64 = 79,
165 
166     /// MSVC calling convention that passes vectors and vector aggregates
167     /// in SSE registers.
168     X86_VectorCall = 80,
169 
170     /// Calling convention used by HipHop Virtual Machine (HHVM) to
171     /// perform calls to and from translation cache, and for calling PHP
172     /// functions.
173     /// HHVM calling convention supports tail/sibling call elimination.
174     HHVM = 81,
175 
176     /// HHVM calling convention for invoking C/C++ helpers.
177     HHVM_C = 82,
178 
179     /// X86_INTR - x86 hardware interrupt context. Callee may take one or two
180     /// parameters, where the 1st represents a pointer to hardware context frame
181     /// and the 2nd represents hardware error code, the presence of the later
182     /// depends on the interrupt vector taken. Valid for both 32- and 64-bit
183     /// subtargets.
184     X86_INTR = 83,
185 
186     /// Used for AVR interrupt routines.
187     AVR_INTR = 84,
188 
189     /// Calling convention used for AVR signal routines.
190     AVR_SIGNAL = 85,
191 
192     /// Calling convention used for special AVR rtlib functions
193     /// which have an "optimized" convention to preserve registers.
194     AVR_BUILTIN = 86,
195 
196     /// Calling convention used for Mesa vertex shaders, or AMDPAL last shader
197     /// stage before rasterization (vertex shader if tessellation and geometry
198     /// are not in use, or otherwise copy shader if one is needed).
199     AMDGPU_VS = 87,
200 
201     /// Calling convention used for Mesa/AMDPAL geometry shaders.
202     AMDGPU_GS = 88,
203 
204     /// Calling convention used for Mesa/AMDPAL pixel shaders.
205     AMDGPU_PS = 89,
206 
207     /// Calling convention used for Mesa/AMDPAL compute shaders.
208     AMDGPU_CS = 90,
209 
210     /// Calling convention for AMDGPU code object kernels.
211     AMDGPU_KERNEL = 91,
212 
213     /// Register calling convention used for parameters transfer optimization
214     X86_RegCall = 92,
215 
216     /// Calling convention used for Mesa/AMDPAL hull shaders (= tessellation
217     /// control shaders).
218     AMDGPU_HS = 93,
219 
220     /// Calling convention used for special MSP430 rtlib functions
221     /// which have an "optimized" convention using additional registers.
222     MSP430_BUILTIN = 94,
223 
224     /// Calling convention used for AMDPAL vertex shader if tessellation is in
225     /// use.
226     AMDGPU_LS = 95,
227 
228     /// Calling convention used for AMDPAL shader stage before geometry shader
229     /// if geometry is in use. So either the domain (= tessellation evaluation)
230     /// shader if tessellation is in use, or otherwise the vertex shader.
231     AMDGPU_ES = 96,
232 
233     // Calling convention between AArch64 Advanced SIMD functions
234     AArch64_VectorCall = 97,
235 
236     /// Calling convention between AArch64 SVE functions
237     AArch64_SVE_VectorCall = 98,
238 
239     /// Calling convention for emscripten __invoke_* functions. The first
240     /// argument is required to be the function ptr being indirectly called.
241     /// The remainder matches the regular calling convention.
242     WASM_EmscriptenInvoke = 99,
243 
244     /// The highest possible calling convention ID. Must be some 2^k - 1.
245     MaxID = 1023
246   };
247 
248 } // end namespace CallingConv
249 
250 } // end namespace llvm
251 
252 #endif // LLVM_IR_CALLINGCONV_H
253