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      1 //===-- MipsBaseInfo.h - Top level definitions for MIPS MC ------*- C++ -*-===//
      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 file contains small standalone helper functions and enum definitions for
     11 // the Mips target useful for the compiler back-end and the MC libraries.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 #ifndef MIPSBASEINFO_H
     15 #define MIPSBASEINFO_H
     16 
     17 #include "MipsFixupKinds.h"
     18 #include "MipsMCTargetDesc.h"
     19 #include "llvm/MC/MCExpr.h"
     20 #include "llvm/Support/DataTypes.h"
     21 #include "llvm/Support/ErrorHandling.h"
     22 
     23 namespace llvm {
     24 
     25 /// MipsII - This namespace holds all of the target specific flags that
     26 /// instruction info tracks.
     27 ///
     28 namespace MipsII {
     29   /// Target Operand Flag enum.
     30   enum TOF {
     31     //===------------------------------------------------------------------===//
     32     // Mips Specific MachineOperand flags.
     33 
     34     MO_NO_FLAG,
     35 
     36     /// MO_GOT16 - Represents the offset into the global offset table at which
     37     /// the address the relocation entry symbol resides during execution.
     38     MO_GOT16,
     39     MO_GOT,
     40 
     41     /// MO_GOT_CALL - Represents the offset into the global offset table at
     42     /// which the address of a call site relocation entry symbol resides
     43     /// during execution. This is different from the above since this flag
     44     /// can only be present in call instructions.
     45     MO_GOT_CALL,
     46 
     47     /// MO_GPREL - Represents the offset from the current gp value to be used
     48     /// for the relocatable object file being produced.
     49     MO_GPREL,
     50 
     51     /// MO_ABS_HI/LO - Represents the hi or low part of an absolute symbol
     52     /// address.
     53     MO_ABS_HI,
     54     MO_ABS_LO,
     55 
     56     /// MO_TLSGD - Represents the offset into the global offset table at which
     57     // the module ID and TSL block offset reside during execution (General
     58     // Dynamic TLS).
     59     MO_TLSGD,
     60 
     61     /// MO_TLSLDM - Represents the offset into the global offset table at which
     62     // the module ID and TSL block offset reside during execution (Local
     63     // Dynamic TLS).
     64     MO_TLSLDM,
     65     MO_DTPREL_HI,
     66     MO_DTPREL_LO,
     67 
     68     /// MO_GOTTPREL - Represents the offset from the thread pointer (Initial
     69     // Exec TLS).
     70     MO_GOTTPREL,
     71 
     72     /// MO_TPREL_HI/LO - Represents the hi and low part of the offset from
     73     // the thread pointer (Local Exec TLS).
     74     MO_TPREL_HI,
     75     MO_TPREL_LO,
     76 
     77     // N32/64 Flags.
     78     MO_GPOFF_HI,
     79     MO_GPOFF_LO,
     80     MO_GOT_DISP,
     81     MO_GOT_PAGE,
     82     MO_GOT_OFST,
     83 
     84     /// MO_HIGHER/HIGHEST - Represents the highest or higher half word of a
     85     /// 64-bit symbol address.
     86     MO_HIGHER,
     87     MO_HIGHEST,
     88 
     89     /// MO_GOT_HI16/LO16, MO_CALL_HI16/LO16 - Relocations used for large GOTs.
     90     MO_GOT_HI16,
     91     MO_GOT_LO16,
     92     MO_CALL_HI16,
     93     MO_CALL_LO16
     94   };
     95 
     96   enum {
     97     //===------------------------------------------------------------------===//
     98     // Instruction encodings.  These are the standard/most common forms for
     99     // Mips instructions.
    100     //
    101 
    102     // Pseudo - This represents an instruction that is a pseudo instruction
    103     // or one that has not been implemented yet.  It is illegal to code generate
    104     // it, but tolerated for intermediate implementation stages.
    105     Pseudo   = 0,
    106 
    107     /// FrmR - This form is for instructions of the format R.
    108     FrmR  = 1,
    109     /// FrmI - This form is for instructions of the format I.
    110     FrmI  = 2,
    111     /// FrmJ - This form is for instructions of the format J.
    112     FrmJ  = 3,
    113     /// FrmFR - This form is for instructions of the format FR.
    114     FrmFR = 4,
    115     /// FrmFI - This form is for instructions of the format FI.
    116     FrmFI = 5,
    117     /// FrmOther - This form is for instructions that have no specific format.
    118     FrmOther = 6,
    119 
    120     FormMask = 15
    121   };
    122 }
    123 
    124 inline static std::pair<const MCSymbolRefExpr*, int64_t>
    125 MipsGetSymAndOffset(const MCFixup &Fixup) {
    126   MCFixupKind FixupKind = Fixup.getKind();
    127 
    128   if ((FixupKind < FirstTargetFixupKind) ||
    129       (FixupKind >= MCFixupKind(Mips::LastTargetFixupKind)))
    130     return std::make_pair((const MCSymbolRefExpr*)0, (int64_t)0);
    131 
    132   const MCExpr *Expr = Fixup.getValue();
    133   MCExpr::ExprKind Kind = Expr->getKind();
    134 
    135   if (Kind == MCExpr::Binary) {
    136     const MCBinaryExpr *BE = static_cast<const MCBinaryExpr*>(Expr);
    137     const MCExpr *LHS = BE->getLHS();
    138     const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(BE->getRHS());
    139 
    140     if ((LHS->getKind() != MCExpr::SymbolRef) || !CE)
    141       return std::make_pair((const MCSymbolRefExpr*)0, (int64_t)0);
    142 
    143     return std::make_pair(cast<MCSymbolRefExpr>(LHS), CE->getValue());
    144   }
    145 
    146   if (Kind != MCExpr::SymbolRef)
    147     return std::make_pair((const MCSymbolRefExpr*)0, (int64_t)0);
    148 
    149   return std::make_pair(cast<MCSymbolRefExpr>(Expr), 0);
    150 }
    151 }
    152 
    153 #endif
    154