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      1 //===- PPCCallingConv.td - Calling Conventions for PowerPC -*- 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 PowerPC 32- and 64-bit
     11 // architectures.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 /// CCIfSubtarget - Match if the current subtarget has a feature F.
     16 class CCIfSubtarget<string F, CCAction A>
     17  : CCIf<!strconcat("State.getTarget().getSubtarget<PPCSubtarget>().", F), A>;
     18 
     19 //===----------------------------------------------------------------------===//
     20 // Return Value Calling Convention
     21 //===----------------------------------------------------------------------===//
     22 
     23 // Return-value convention for PowerPC
     24 def RetCC_PPC : CallingConv<[
     25   CCIfType<[i32], CCAssignToReg<[R3, R4, R5, R6, R7, R8, R9, R10]>>,
     26   CCIfType<[i64], CCAssignToReg<[X3, X4, X5, X6]>>,
     27   
     28   CCIfType<[f32], CCAssignToReg<[F1]>>,
     29   CCIfType<[f64], CCAssignToReg<[F1, F2]>>,
     30   
     31   // Vector types are always returned in V2.
     32   CCIfType<[v16i8, v8i16, v4i32, v4f32], CCAssignToReg<[V2]>>
     33 ]>;
     34 
     35 
     36 //===----------------------------------------------------------------------===//
     37 // PowerPC Argument Calling Conventions
     38 //===----------------------------------------------------------------------===//
     39 /*
     40 def CC_PPC : CallingConv<[
     41   // The first 8 integer arguments are passed in integer registers.
     42   CCIfType<[i32], CCAssignToReg<[R3, R4, R5, R6, R7, R8, R9, R10]>>,
     43   CCIfType<[i64], CCAssignToReg<[X3, X4, X5, X6, X7, X8, X9, X10]>>,
     44   
     45   // Common sub-targets passes FP values in F1 - F13
     46   CCIfType<[f32, f64], 
     47            CCAssignToReg<[F1, F2, F3, F4, F5, F6, F7, F8,F9,F10,F11,F12,F13]>>,
     48            
     49   // The first 12 Vector arguments are passed in altivec registers.
     50   CCIfType<[v16i8, v8i16, v4i32, v4f32],
     51               CCAssignToReg<[V2, V3, V4, V5, V6, V7, V8, V9, V10,V11,V12,V13]>>
     52 
     53 /*
     54   // Integer/FP values get stored in stack slots that are 8 bytes in size and
     55   // 8-byte aligned if there are no more registers to hold them.
     56   CCIfType<[i32, i64, f32, f64], CCAssignToStack<8, 8>>,
     57   
     58   // Vectors get 16-byte stack slots that are 16-byte aligned.
     59   CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64],
     60               CCAssignToStack<16, 16>>*/
     61 ]>;
     62 
     63 */
     64 
     65 //===----------------------------------------------------------------------===//
     66 // PowerPC System V Release 4 ABI
     67 //===----------------------------------------------------------------------===//
     68 
     69 def CC_PPC_SVR4_Common : CallingConv<[
     70   // The ABI requires i64 to be passed in two adjacent registers with the first
     71   // register having an odd register number.
     72   CCIfType<[i32], CCIfSplit<CCCustom<"CC_PPC_SVR4_Custom_AlignArgRegs">>>,
     73 
     74   // The first 8 integer arguments are passed in integer registers.
     75   CCIfType<[i32], CCAssignToReg<[R3, R4, R5, R6, R7, R8, R9, R10]>>,
     76 
     77   // Make sure the i64 words from a long double are either both passed in
     78   // registers or both passed on the stack.
     79   CCIfType<[f64], CCIfSplit<CCCustom<"CC_PPC_SVR4_Custom_AlignFPArgRegs">>>,
     80   
     81   // FP values are passed in F1 - F8.
     82   CCIfType<[f32, f64], CCAssignToReg<[F1, F2, F3, F4, F5, F6, F7, F8]>>,
     83 
     84   // Split arguments have an alignment of 8 bytes on the stack.
     85   CCIfType<[i32], CCIfSplit<CCAssignToStack<4, 8>>>,
     86   
     87   CCIfType<[i32], CCAssignToStack<4, 4>>,
     88   
     89   // Floats are stored in double precision format, thus they have the same
     90   // alignment and size as doubles.
     91   CCIfType<[f32,f64], CCAssignToStack<8, 8>>,  
     92 
     93   // Vectors get 16-byte stack slots that are 16-byte aligned.
     94   CCIfType<[v16i8, v8i16, v4i32, v4f32], CCAssignToStack<16, 16>>
     95 ]>;
     96 
     97 // This calling convention puts vector arguments always on the stack. It is used
     98 // to assign vector arguments which belong to the variable portion of the
     99 // parameter list of a variable argument function.
    100 def CC_PPC_SVR4_VarArg : CallingConv<[
    101   CCDelegateTo<CC_PPC_SVR4_Common>
    102 ]>;
    103 
    104 // In contrast to CC_PPC_SVR4_VarArg, this calling convention first tries to put
    105 // vector arguments in vector registers before putting them on the stack.
    106 def CC_PPC_SVR4 : CallingConv<[
    107   // The first 12 Vector arguments are passed in AltiVec registers.
    108   CCIfType<[v16i8, v8i16, v4i32, v4f32],
    109            CCAssignToReg<[V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13]>>,
    110            
    111   CCDelegateTo<CC_PPC_SVR4_Common>
    112 ]>;  
    113 
    114 // Helper "calling convention" to handle aggregate by value arguments.
    115 // Aggregate by value arguments are always placed in the local variable space
    116 // of the caller. This calling convention is only used to assign those stack
    117 // offsets in the callers stack frame.
    118 //
    119 // Still, the address of the aggregate copy in the callers stack frame is passed
    120 // in a GPR (or in the parameter list area if all GPRs are allocated) from the
    121 // caller to the callee. The location for the address argument is assigned by
    122 // the CC_PPC_SVR4 calling convention.
    123 //
    124 // The only purpose of CC_PPC_SVR4_Custom_Dummy is to skip arguments which are
    125 // not passed by value.
    126  
    127 def CC_PPC_SVR4_ByVal : CallingConv<[
    128   CCIfByVal<CCPassByVal<4, 4>>,
    129   
    130   CCCustom<"CC_PPC_SVR4_Custom_Dummy">
    131 ]>;
    132 
    133