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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     /// 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