1//===-- SparcCallingConv.td - Calling Conventions Sparc ----*- tablegen -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This describes the calling conventions for the Sparc architectures. 11// 12//===----------------------------------------------------------------------===// 13 14//===----------------------------------------------------------------------===// 15// SPARC v8 32-bit. 16//===----------------------------------------------------------------------===// 17 18def CC_Sparc32 : CallingConv<[ 19 // Custom assign SRet to [sp+64]. 20 CCIfSRet<CCCustom<"CC_Sparc_Assign_SRet">>, 21 // i32 f32 arguments get passed in integer registers if there is space. 22 CCIfType<[i32, f32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>, 23 // f64 arguments are split and passed through registers or through stack. 24 CCIfType<[f64], CCCustom<"CC_Sparc_Assign_Split_64">>, 25 // As are v2i32 arguments (this would be the default behavior for 26 // v2i32 if it wasn't allocated to the IntPair register-class) 27 CCIfType<[v2i32], CCCustom<"CC_Sparc_Assign_Split_64">>, 28 29 30 // Alternatively, they are assigned to the stack in 4-byte aligned units. 31 CCAssignToStack<4, 4> 32]>; 33 34def RetCC_Sparc32 : CallingConv<[ 35 CCIfType<[i32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>, 36 CCIfType<[f32], CCAssignToReg<[F0, F1, F2, F3]>>, 37 CCIfType<[f64], CCAssignToReg<[D0, D1]>>, 38 CCIfType<[v2i32], CCCustom<"CC_Sparc_Assign_Ret_Split_64">> 39]>; 40 41 42//===----------------------------------------------------------------------===// 43// SPARC v9 64-bit. 44//===----------------------------------------------------------------------===// 45// 46// The 64-bit ABI conceptually assigns all function arguments to a parameter 47// array starting at [%fp+BIAS+128] in the callee's stack frame. All arguments 48// occupy a multiple of 8 bytes in the array. Integer arguments are extended to 49// 64 bits by the caller. Floats are right-aligned in their 8-byte slot, the 50// first 4 bytes in the slot are undefined. 51// 52// The integer registers %i0 to %i5 shadow the first 48 bytes of the parameter 53// array at fixed offsets. Integer arguments are promoted to registers when 54// possible. 55// 56// The floating point registers %f0 to %f31 shadow the first 128 bytes of the 57// parameter array at fixed offsets. Float and double parameters are promoted 58// to these registers when possible. 59// 60// Structs up to 16 bytes in size are passed by value. They are right-aligned 61// in one or two 8-byte slots in the parameter array. Struct members are 62// promoted to both floating point and integer registers when possible. A 63// struct containing two floats would thus be passed in %f0 and %f1, while two 64// float function arguments would occupy 8 bytes each, and be passed in %f1 and 65// %f3. 66// 67// When a struct { int, float } is passed by value, the int goes in the high 68// bits of an integer register while the float goes in a floating point 69// register. 70// 71// The difference is encoded in LLVM IR using the inreg atttribute on function 72// arguments: 73// 74// C: void f(float, float); 75// IR: declare void f(float %f1, float %f3) 76// 77// C: void f(struct { float f0, f1; }); 78// IR: declare void f(float inreg %f0, float inreg %f1) 79// 80// C: void f(int, float); 81// IR: declare void f(int signext %i0, float %f3) 82// 83// C: void f(struct { int i0high; float f1; }); 84// IR: declare void f(i32 inreg %i0high, float inreg %f1) 85// 86// Two ints in a struct are simply coerced to i64: 87// 88// C: void f(struct { int i0high, i0low; }); 89// IR: declare void f(i64 %i0.coerced) 90// 91// The frontend and backend divide the task of producing ABI compliant code for 92// C functions. The C frontend will: 93// 94// - Annotate integer arguments with zeroext or signext attributes. 95// 96// - Split structs into one or two 64-bit sized chunks, or 32-bit chunks with 97// inreg attributes. 98// 99// - Pass structs larger than 16 bytes indirectly with an explicit pointer 100// argument. The byval attribute is not used. 101// 102// The backend will: 103// 104// - Assign all arguments to 64-bit aligned stack slots, 32-bits for inreg. 105// 106// - Promote to integer or floating point registers depending on type. 107// 108// Function return values are passed exactly like function arguments, except a 109// struct up to 32 bytes in size can be returned in registers. 110 111// Function arguments AND most return values. 112def CC_Sparc64 : CallingConv<[ 113 // The frontend uses the inreg flag to indicate i32 and float arguments from 114 // structs. These arguments are not promoted to 64 bits, but they can still 115 // be assigned to integer and float registers. 116 CCIfInReg<CCIfType<[i32, f32], CCCustom<"CC_Sparc64_Half">>>, 117 118 // All integers are promoted to i64 by the caller. 119 CCIfType<[i32], CCPromoteToType<i64>>, 120 121 // Custom assignment is required because stack space is reserved for all 122 // arguments whether they are passed in registers or not. 123 CCCustom<"CC_Sparc64_Full"> 124]>; 125 126def RetCC_Sparc64 : CallingConv<[ 127 // A single f32 return value always goes in %f0. The ABI doesn't specify what 128 // happens to multiple f32 return values outside a struct. 129 CCIfType<[f32], CCCustom<"CC_Sparc64_Half">>, 130 131 // Otherwise, return values are passed exactly like arguments. 132 CCDelegateTo<CC_Sparc64> 133]>; 134 135// Callee-saved registers are handled by the register window mechanism. 136def CSR : CalleeSavedRegs<(add)> { 137 let OtherPreserved = (add (sequence "I%u", 0, 7), 138 (sequence "L%u", 0, 7)); 139} 140 141// Callee-saved registers for calls with ReturnsTwice attribute. 142def RTCSR : CalleeSavedRegs<(add)> { 143 let OtherPreserved = (add I6, I7); 144} 145