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      1 //===-- MipsCallingConv.td - Calling Conventions for Mips --*- 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 // This describes the calling conventions for Mips architecture.
     10 //===----------------------------------------------------------------------===//
     11 
     12 /// CCIfSubtarget - Match if the current subtarget has a feature F.
     13 class CCIfSubtarget<string F, CCAction A, string Invert = "">
     14     : CCIf<!strconcat(Invert,
     15                       "static_cast<const MipsSubtarget&>"
     16 			"(State.getMachineFunction().getSubtarget()).",
     17                       F),
     18            A>;
     19 
     20 // The inverse of CCIfSubtarget
     21 class CCIfSubtargetNot<string F, CCAction A> : CCIfSubtarget<F, A, "!">;
     22 
     23 /// Match if the original argument (before lowering) was a float.
     24 /// For example, this is true for i32's that were lowered from soft-float.
     25 class CCIfOrigArgWasNotFloat<CCAction A>
     26     : CCIf<"!static_cast<MipsCCState *>(&State)->WasOriginalArgFloat(ValNo)",
     27            A>;
     28 
     29 /// Match if the original argument (before lowering) was a 128-bit float (i.e.
     30 /// long double).
     31 class CCIfOrigArgWasF128<CCAction A>
     32     : CCIf<"static_cast<MipsCCState *>(&State)->WasOriginalArgF128(ValNo)", A>;
     33 
     34 /// Match if this specific argument is a vararg.
     35 /// This is slightly different fro CCIfIsVarArg which matches if any argument is
     36 /// a vararg.
     37 class CCIfArgIsVarArg<CCAction A>
     38     : CCIf<"!static_cast<MipsCCState *>(&State)->IsCallOperandFixed(ValNo)", A>;
     39 
     40 /// Match if the return was a floating point vector.
     41 class CCIfOrigArgWasNotVectorFloat<CCAction A>
     42     : CCIf<"!static_cast<MipsCCState *>(&State)"
     43                 "->WasOriginalRetVectorFloat(ValNo)", A>;
     44 
     45 /// Match if the special calling conv is the specified value.
     46 class CCIfSpecialCallingConv<string CC, CCAction A>
     47     : CCIf<"static_cast<MipsCCState *>(&State)->getSpecialCallingConv() == "
     48                "MipsCCState::" # CC, A>;
     49 
     50 // For soft-float, f128 values are returned in A0_64 rather than V1_64.
     51 def RetCC_F128SoftFloat : CallingConv<[
     52   CCAssignToReg<[V0_64, A0_64]>
     53 ]>;
     54 
     55 // For hard-float, f128 values are returned as a pair of f64's rather than a
     56 // pair of i64's.
     57 def RetCC_F128HardFloat : CallingConv<[
     58   CCBitConvertToType<f64>,
     59 
     60   // Contrary to the ABI documentation, a struct containing a long double is
     61   // returned in $f0, and $f1 instead of the usual $f0, and $f2. This is to
     62   // match the de facto ABI as implemented by GCC.
     63   CCIfInReg<CCAssignToReg<[D0_64, D1_64]>>,
     64 
     65   CCAssignToReg<[D0_64, D2_64]>
     66 ]>;
     67 
     68 // Handle F128 specially since we can't identify the original type during the
     69 // tablegen-erated code.
     70 def RetCC_F128 : CallingConv<[
     71   CCIfSubtarget<"useSoftFloat()",
     72       CCIfType<[i64], CCDelegateTo<RetCC_F128SoftFloat>>>,
     73   CCIfSubtargetNot<"useSoftFloat()",
     74       CCIfType<[i64], CCDelegateTo<RetCC_F128HardFloat>>>
     75 ]>;
     76 
     77 //===----------------------------------------------------------------------===//
     78 // Mips O32 Calling Convention
     79 //===----------------------------------------------------------------------===//
     80 
     81 def CC_MipsO32 : CallingConv<[
     82   // Promote i8/i16 arguments to i32.
     83   CCIfType<[i1, i8, i16], CCPromoteToType<i32>>,
     84 
     85   // Integer values get stored in stack slots that are 4 bytes in
     86   // size and 4-byte aligned.
     87   CCIfType<[i32, f32], CCAssignToStack<4, 4>>,
     88 
     89   // Integer values get stored in stack slots that are 8 bytes in
     90   // size and 8-byte aligned.
     91   CCIfType<[f64], CCAssignToStack<8, 8>>
     92 ]>;
     93 
     94 // Only the return rules are defined here for O32. The rules for argument
     95 // passing are defined in MipsISelLowering.cpp.
     96 def RetCC_MipsO32 : CallingConv<[
     97   // Promote i1/i8/i16 return values to i32.
     98   CCIfType<[i1, i8, i16], CCPromoteToType<i32>>,
     99 
    100   // i32 are returned in registers V0, V1, A0, A1, unless the original return
    101   // type was a vector of floats.
    102   CCIfOrigArgWasNotVectorFloat<CCIfType<[i32],
    103                                         CCAssignToReg<[V0, V1, A0, A1]>>>,
    104 
    105   // f32 are returned in registers F0, F2
    106   CCIfType<[f32], CCAssignToReg<[F0, F2]>>,
    107 
    108   // f64 arguments are returned in D0_64 and D2_64 in FP64bit mode or
    109   // in D0 and D1 in FP32bit mode.
    110   CCIfType<[f64], CCIfSubtarget<"isFP64bit()", CCAssignToReg<[D0_64, D2_64]>>>,
    111   CCIfType<[f64], CCIfSubtargetNot<"isFP64bit()", CCAssignToReg<[D0, D1]>>>
    112 ]>;
    113 
    114 def CC_MipsO32_FP32 : CustomCallingConv;
    115 def CC_MipsO32_FP64 : CustomCallingConv;
    116 
    117 def CC_MipsO32_FP : CallingConv<[
    118   CCIfSubtargetNot<"isFP64bit()", CCDelegateTo<CC_MipsO32_FP32>>,
    119   CCIfSubtarget<"isFP64bit()", CCDelegateTo<CC_MipsO32_FP64>>
    120 ]>;
    121 
    122 //===----------------------------------------------------------------------===//
    123 // Mips N32/64 Calling Convention
    124 //===----------------------------------------------------------------------===//
    125 
    126 def CC_MipsN_SoftFloat : CallingConv<[
    127   CCAssignToRegWithShadow<[A0, A1, A2, A3,
    128                            T0, T1, T2, T3],
    129                           [D12_64, D13_64, D14_64, D15_64,
    130                            D16_64, D17_64, D18_64, D19_64]>,
    131   CCAssignToStack<4, 8>
    132 ]>;
    133 
    134 def CC_MipsN : CallingConv<[
    135   CCIfType<[i8, i16, i32, i64],
    136       CCIfSubtargetNot<"isLittle()",
    137           CCIfInReg<CCPromoteToUpperBitsInType<i64>>>>,
    138 
    139   // All integers (except soft-float integers) are promoted to 64-bit.
    140   CCIfType<[i8, i16, i32], CCIfOrigArgWasNotFloat<CCPromoteToType<i64>>>,
    141 
    142   // The only i32's we have left are soft-float arguments.
    143   CCIfSubtarget<"useSoftFloat()", CCIfType<[i32], CCDelegateTo<CC_MipsN_SoftFloat>>>,
    144 
    145   // Integer arguments are passed in integer registers.
    146   CCIfType<[i64], CCAssignToRegWithShadow<[A0_64, A1_64, A2_64, A3_64,
    147                                            T0_64, T1_64, T2_64, T3_64],
    148                                           [D12_64, D13_64, D14_64, D15_64,
    149                                            D16_64, D17_64, D18_64, D19_64]>>,
    150 
    151   // f32 arguments are passed in single precision FP registers.
    152   CCIfType<[f32], CCAssignToRegWithShadow<[F12, F13, F14, F15,
    153                                            F16, F17, F18, F19],
    154                                           [A0_64, A1_64, A2_64, A3_64,
    155                                            T0_64, T1_64, T2_64, T3_64]>>,
    156 
    157   // f64 arguments are passed in double precision FP registers.
    158   CCIfType<[f64], CCAssignToRegWithShadow<[D12_64, D13_64, D14_64, D15_64,
    159                                            D16_64, D17_64, D18_64, D19_64],
    160                                           [A0_64, A1_64, A2_64, A3_64,
    161                                            T0_64, T1_64, T2_64, T3_64]>>,
    162 
    163   // All stack parameter slots become 64-bit doublewords and are 8-byte aligned.
    164   CCIfType<[f32], CCAssignToStack<4, 8>>,
    165   CCIfType<[i64, f64], CCAssignToStack<8, 8>>
    166 ]>;
    167 
    168 // N32/64 variable arguments.
    169 // All arguments are passed in integer registers.
    170 def CC_MipsN_VarArg : CallingConv<[
    171   CCIfType<[i8, i16, i32, i64],
    172       CCIfSubtargetNot<"isLittle()",
    173           CCIfInReg<CCPromoteToUpperBitsInType<i64>>>>,
    174 
    175   // All integers are promoted to 64-bit.
    176   CCIfType<[i8, i16, i32], CCPromoteToType<i64>>,
    177 
    178   CCIfType<[f32], CCAssignToReg<[A0, A1, A2, A3, T0, T1, T2, T3]>>,
    179 
    180   CCIfType<[i64, f64], CCAssignToReg<[A0_64, A1_64, A2_64, A3_64,
    181                                       T0_64, T1_64, T2_64, T3_64]>>,
    182 
    183   // All stack parameter slots become 64-bit doublewords and are 8-byte aligned.
    184   CCIfType<[f32], CCAssignToStack<4, 8>>,
    185   CCIfType<[i64, f64], CCAssignToStack<8, 8>>
    186 ]>;
    187 
    188 def RetCC_MipsN : CallingConv<[
    189   // f128 needs to be handled similarly to f32 and f64. However, f128 is not
    190   // legal and is lowered to i128 which is further lowered to a pair of i64's.
    191   // This presents us with a problem for the calling convention since hard-float
    192   // still needs to pass them in FPU registers, and soft-float needs to use $v0,
    193   // and $a0 instead of the usual $v0, and $v1. We therefore resort to a
    194   // pre-analyze (see PreAnalyzeReturnForF128()) step to pass information on
    195   // whether the result was originally an f128 into the tablegen-erated code.
    196   //
    197   // f128 should only occur for the N64 ABI where long double is 128-bit. On
    198   // N32, long double is equivalent to double.
    199   CCIfType<[i64], CCIfOrigArgWasF128<CCDelegateTo<RetCC_F128>>>,
    200 
    201   // Aggregate returns are positioned at the lowest address in the slot for
    202   // both little and big-endian targets. When passing in registers, this
    203   // requires that big-endian targets shift the value into the upper bits.
    204   CCIfSubtarget<"isLittle()",
    205       CCIfType<[i8, i16, i32, i64], CCIfInReg<CCPromoteToType<i64>>>>,
    206   CCIfSubtargetNot<"isLittle()",
    207       CCIfType<[i8, i16, i32, i64],
    208           CCIfInReg<CCPromoteToUpperBitsInType<i64>>>>,
    209 
    210   // i64 are returned in registers V0_64, V1_64
    211   CCIfType<[i64], CCAssignToReg<[V0_64, V1_64]>>,
    212 
    213   // f32 are returned in registers F0, F2
    214   CCIfType<[f32], CCAssignToReg<[F0, F2]>>,
    215 
    216   // f64 are returned in registers D0, D2
    217   CCIfType<[f64], CCAssignToReg<[D0_64, D2_64]>>
    218 ]>;
    219 
    220 //===----------------------------------------------------------------------===//
    221 // Mips FastCC Calling Convention
    222 //===----------------------------------------------------------------------===//
    223 def CC_MipsO32_FastCC : CallingConv<[
    224   // f64 arguments are passed in double-precision floating pointer registers.
    225   CCIfType<[f64], CCIfSubtargetNot<"isFP64bit()",
    226                                    CCAssignToReg<[D0, D1, D2, D3, D4, D5, D6,
    227                                                   D7, D8, D9]>>>,
    228   CCIfType<[f64], CCIfSubtarget<"isFP64bit()", CCIfSubtarget<"useOddSPReg()",
    229                                 CCAssignToReg<[D0_64, D1_64, D2_64, D3_64,
    230                                                D4_64, D5_64, D6_64, D7_64,
    231                                                D8_64, D9_64, D10_64, D11_64,
    232                                                D12_64, D13_64, D14_64, D15_64,
    233                                                D16_64, D17_64, D18_64,
    234                                                D19_64]>>>>,
    235   CCIfType<[f64], CCIfSubtarget<"isFP64bit()", CCIfSubtarget<"noOddSPReg()",
    236                                 CCAssignToReg<[D0_64, D2_64, D4_64, D6_64,
    237                                                D8_64, D10_64, D12_64, D14_64,
    238                                                D16_64, D18_64]>>>>,
    239 
    240   // Stack parameter slots for f64 are 64-bit doublewords and 8-byte aligned.
    241   CCIfType<[f64], CCAssignToStack<8, 8>>
    242 ]>;
    243 
    244 def CC_MipsN_FastCC : CallingConv<[
    245   // Integer arguments are passed in integer registers.
    246   CCIfType<[i64], CCAssignToReg<[A0_64, A1_64, A2_64, A3_64, T0_64, T1_64,
    247                                  T2_64, T3_64, T4_64, T5_64, T6_64, T7_64,
    248                                  T8_64, V1_64]>>,
    249 
    250   // f64 arguments are passed in double-precision floating pointer registers.
    251   CCIfType<[f64], CCAssignToReg<[D0_64, D1_64, D2_64, D3_64, D4_64, D5_64,
    252                                  D6_64, D7_64, D8_64, D9_64, D10_64, D11_64,
    253                                  D12_64, D13_64, D14_64, D15_64, D16_64, D17_64,
    254                                  D18_64, D19_64]>>,
    255 
    256   // Stack parameter slots for i64 and f64 are 64-bit doublewords and
    257   // 8-byte aligned.
    258   CCIfType<[i64, f64], CCAssignToStack<8, 8>>
    259 ]>;
    260 
    261 def CC_Mips_FastCC : CallingConv<[
    262   // Handles byval parameters.
    263   CCIfByVal<CCPassByVal<4, 4>>,
    264 
    265   // Promote i8/i16 arguments to i32.
    266   CCIfType<[i8, i16], CCPromoteToType<i32>>,
    267 
    268   // Integer arguments are passed in integer registers. All scratch registers,
    269   // except for AT, V0 and T9, are available to be used as argument registers.
    270   CCIfType<[i32], CCIfSubtargetNot<"isTargetNaCl()",
    271       CCAssignToReg<[A0, A1, A2, A3, T0, T1, T2, T3, T4, T5, T6, T7, T8, V1]>>>,
    272 
    273   // In NaCl, T6, T7 and T8 are reserved and not available as argument
    274   // registers for fastcc.  T6 contains the mask for sandboxing control flow
    275   // (indirect jumps and calls).  T7 contains the mask for sandboxing memory
    276   // accesses (loads and stores).  T8 contains the thread pointer.
    277   CCIfType<[i32], CCIfSubtarget<"isTargetNaCl()",
    278       CCAssignToReg<[A0, A1, A2, A3, T0, T1, T2, T3, T4, T5, V1]>>>,
    279 
    280   // f32 arguments are passed in single-precision floating pointer registers.
    281   CCIfType<[f32], CCIfSubtarget<"useOddSPReg()",
    282       CCAssignToReg<[F0, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, F13,
    283                      F14, F15, F16, F17, F18, F19]>>>,
    284 
    285   // Don't use odd numbered single-precision registers for -mno-odd-spreg.
    286   CCIfType<[f32], CCIfSubtarget<"noOddSPReg()",
    287       CCAssignToReg<[F0, F2, F4, F6, F8, F10, F12, F14, F16, F18]>>>,
    288 
    289   // Stack parameter slots for i32 and f32 are 32-bit words and 4-byte aligned.
    290   CCIfType<[i32, f32], CCAssignToStack<4, 4>>,
    291 
    292   CCIfSubtarget<"isABI_O32()", CCDelegateTo<CC_MipsO32_FastCC>>,
    293   CCDelegateTo<CC_MipsN_FastCC>
    294 ]>;
    295 
    296 //===----------------------------------------------------------------------===//
    297 // Mips Calling Convention Dispatch
    298 //===----------------------------------------------------------------------===//
    299 
    300 def RetCC_Mips : CallingConv<[
    301   CCIfSubtarget<"isABI_N32()", CCDelegateTo<RetCC_MipsN>>,
    302   CCIfSubtarget<"isABI_N64()", CCDelegateTo<RetCC_MipsN>>,
    303   CCDelegateTo<RetCC_MipsO32>
    304 ]>;
    305 
    306 def CC_Mips_ByVal : CallingConv<[
    307   CCIfSubtarget<"isABI_O32()", CCIfByVal<CCPassByVal<4, 4>>>,
    308   CCIfByVal<CCPassByVal<8, 8>>
    309 ]>;
    310 
    311 def CC_Mips16RetHelper : CallingConv<[
    312   CCIfByVal<CCDelegateTo<CC_Mips_ByVal>>,
    313 
    314   // Integer arguments are passed in integer registers.
    315   CCIfType<[i32], CCAssignToReg<[V0, V1, A0, A1]>>
    316 ]>;
    317 
    318 def CC_Mips_FixedArg : CallingConv<[
    319   // Mips16 needs special handling on some functions.
    320   CCIf<"State.getCallingConv() != CallingConv::Fast",
    321       CCIfSpecialCallingConv<"Mips16RetHelperConv",
    322            CCDelegateTo<CC_Mips16RetHelper>>>,
    323 
    324   CCIfByVal<CCDelegateTo<CC_Mips_ByVal>>,
    325 
    326   // f128 needs to be handled similarly to f32 and f64 on hard-float. However,
    327   // f128 is not legal and is lowered to i128 which is further lowered to a pair
    328   // of i64's.
    329   // This presents us with a problem for the calling convention since hard-float
    330   // still needs to pass them in FPU registers. We therefore resort to a
    331   // pre-analyze (see PreAnalyzeFormalArgsForF128()) step to pass information on
    332   // whether the argument was originally an f128 into the tablegen-erated code.
    333   //
    334   // f128 should only occur for the N64 ABI where long double is 128-bit. On
    335   // N32, long double is equivalent to double.
    336   CCIfType<[i64],
    337       CCIfSubtargetNot<"useSoftFloat()",
    338           CCIfOrigArgWasF128<CCBitConvertToType<f64>>>>,
    339 
    340   CCIfCC<"CallingConv::Fast", CCDelegateTo<CC_Mips_FastCC>>,
    341 
    342   CCIfSubtarget<"isABI_O32()", CCDelegateTo<CC_MipsO32_FP>>,
    343   CCDelegateTo<CC_MipsN>
    344 ]>;
    345 
    346 def CC_Mips_VarArg : CallingConv<[
    347   CCIfByVal<CCDelegateTo<CC_Mips_ByVal>>,
    348 
    349   CCIfSubtarget<"isABI_O32()", CCDelegateTo<CC_MipsO32_FP>>,
    350   CCDelegateTo<CC_MipsN_VarArg>
    351 ]>;
    352 
    353 def CC_Mips : CallingConv<[
    354   CCIfVarArg<CCIfArgIsVarArg<CCDelegateTo<CC_Mips_VarArg>>>,
    355   CCDelegateTo<CC_Mips_FixedArg>
    356 ]>;
    357 
    358 //===----------------------------------------------------------------------===//
    359 // Callee-saved register lists.
    360 //===----------------------------------------------------------------------===//
    361 
    362 def CSR_SingleFloatOnly : CalleeSavedRegs<(add (sequence "F%u", 31, 20), RA, FP,
    363                                                (sequence "S%u", 7, 0))>;
    364 
    365 def CSR_O32_FPXX : CalleeSavedRegs<(add (sequence "D%u", 15, 10), RA, FP,
    366                                         (sequence "S%u", 7, 0))> {
    367   let OtherPreserved = (add (decimate (sequence "F%u", 30, 20), 2));
    368 }
    369 
    370 def CSR_O32 : CalleeSavedRegs<(add (sequence "D%u", 15, 10), RA, FP,
    371                                    (sequence "S%u", 7, 0))>;
    372 
    373 def CSR_O32_FP64 :
    374   CalleeSavedRegs<(add (decimate (sequence "D%u_64", 30, 20), 2), RA, FP,
    375                        (sequence "S%u", 7, 0))>;
    376 
    377 def CSR_N32 : CalleeSavedRegs<(add D20_64, D22_64, D24_64, D26_64, D28_64,
    378                                    D30_64, RA_64, FP_64, GP_64,
    379                                    (sequence "S%u_64", 7, 0))>;
    380 
    381 def CSR_N64 : CalleeSavedRegs<(add (sequence "D%u_64", 31, 24), RA_64, FP_64,
    382                                    GP_64, (sequence "S%u_64", 7, 0))>;
    383 
    384 def CSR_Mips16RetHelper :
    385   CalleeSavedRegs<(add V0, V1, FP,
    386                    (sequence "A%u", 3, 0), (sequence "S%u", 7, 0),
    387                    (sequence "D%u", 15, 10))>;
    388 
    389 def CSR_Interrupt_32R6 : CalleeSavedRegs<(add (sequence "A%u", 3, 0),
    390                                               (sequence "S%u", 7, 0),
    391                                               (sequence "V%u", 1, 0),
    392                                               (sequence "T%u", 9, 0),
    393                                               RA, FP, GP, AT)>;
    394 
    395 def CSR_Interrupt_32 : CalleeSavedRegs<(add (sequence "A%u", 3, 0),
    396                                             (sequence "S%u", 7, 0),
    397                                             (sequence "V%u", 1, 0),
    398                                             (sequence "T%u", 9, 0),
    399                                             RA, FP, GP, AT, LO0, HI0)>;
    400 
    401 def CSR_Interrupt_64R6 : CalleeSavedRegs<(add (sequence "A%u_64", 3, 0),
    402                                               (sequence "V%u_64", 1, 0),
    403                                               (sequence "S%u_64", 7, 0),
    404                                               (sequence "T%u_64", 9, 0),
    405                                               RA_64, FP_64, GP_64, AT_64)>;
    406 
    407 def CSR_Interrupt_64 : CalleeSavedRegs<(add (sequence "A%u_64", 3, 0),
    408                                             (sequence "S%u_64", 7, 0),
    409                                             (sequence "T%u_64", 9, 0),
    410                                             (sequence "V%u_64", 1, 0),
    411                                             RA_64, FP_64, GP_64, AT_64,
    412                                             LO0_64, HI0_64)>;
    413