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      1 //===- PowerPCSubtarget.cpp - PPC Subtarget Information -------------------===//
      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 implements the PPC specific subclass of TargetSubtargetInfo.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "PPCSubtarget.h"
     15 #include "PPC.h"
     16 #include "llvm/GlobalValue.h"
     17 #include "llvm/Target/TargetMachine.h"
     18 #include "llvm/Support/TargetRegistry.h"
     19 #include <cstdlib>
     20 
     21 #define GET_SUBTARGETINFO_TARGET_DESC
     22 #define GET_SUBTARGETINFO_CTOR
     23 #include "PPCGenSubtargetInfo.inc"
     24 
     25 using namespace llvm;
     26 
     27 #if defined(__APPLE__)
     28 #include <mach/mach.h>
     29 #include <mach/mach_host.h>
     30 #include <mach/host_info.h>
     31 #include <mach/machine.h>
     32 
     33 /// GetCurrentPowerPCFeatures - Returns the current CPUs features.
     34 static const char *GetCurrentPowerPCCPU() {
     35   host_basic_info_data_t hostInfo;
     36   mach_msg_type_number_t infoCount;
     37 
     38   infoCount = HOST_BASIC_INFO_COUNT;
     39   host_info(mach_host_self(), HOST_BASIC_INFO, (host_info_t)&hostInfo,
     40             &infoCount);
     41 
     42   if (hostInfo.cpu_type != CPU_TYPE_POWERPC) return "generic";
     43 
     44   switch(hostInfo.cpu_subtype) {
     45   case CPU_SUBTYPE_POWERPC_601:   return "601";
     46   case CPU_SUBTYPE_POWERPC_602:   return "602";
     47   case CPU_SUBTYPE_POWERPC_603:   return "603";
     48   case CPU_SUBTYPE_POWERPC_603e:  return "603e";
     49   case CPU_SUBTYPE_POWERPC_603ev: return "603ev";
     50   case CPU_SUBTYPE_POWERPC_604:   return "604";
     51   case CPU_SUBTYPE_POWERPC_604e:  return "604e";
     52   case CPU_SUBTYPE_POWERPC_620:   return "620";
     53   case CPU_SUBTYPE_POWERPC_750:   return "750";
     54   case CPU_SUBTYPE_POWERPC_7400:  return "7400";
     55   case CPU_SUBTYPE_POWERPC_7450:  return "7450";
     56   case CPU_SUBTYPE_POWERPC_970:   return "970";
     57   default: ;
     58   }
     59 
     60   return "generic";
     61 }
     62 #endif
     63 
     64 
     65 PPCSubtarget::PPCSubtarget(const std::string &TT, const std::string &CPU,
     66                            const std::string &FS, bool is64Bit)
     67   : PPCGenSubtargetInfo(TT, CPU, FS)
     68   , StackAlignment(16)
     69   , DarwinDirective(PPC::DIR_NONE)
     70   , IsGigaProcessor(false)
     71   , Has64BitSupport(false)
     72   , Use64BitRegs(false)
     73   , IsPPC64(is64Bit)
     74   , HasAltivec(false)
     75   , HasFSQRT(false)
     76   , HasSTFIWX(false)
     77   , IsBookE(false)
     78   , HasLazyResolverStubs(false)
     79   , IsJITCodeModel(false)
     80   , TargetTriple(TT) {
     81 
     82   // Determine default and user specified characteristics
     83   std::string CPUName = CPU;
     84   if (CPUName.empty())
     85     CPUName = "generic";
     86 #if defined(__APPLE__)
     87   if (CPUName == "generic")
     88     CPUName = GetCurrentPowerPCCPU();
     89 #endif
     90 
     91   // Parse features string.
     92   ParseSubtargetFeatures(CPUName, FS);
     93 
     94   // Initialize scheduling itinerary for the specified CPU.
     95   InstrItins = getInstrItineraryForCPU(CPUName);
     96 
     97   // If we are generating code for ppc64, verify that options make sense.
     98   if (is64Bit) {
     99     Has64BitSupport = true;
    100     // Silently force 64-bit register use on ppc64.
    101     Use64BitRegs = true;
    102   }
    103 
    104   // If the user requested use of 64-bit regs, but the cpu selected doesn't
    105   // support it, ignore.
    106   if (use64BitRegs() && !has64BitSupport())
    107     Use64BitRegs = false;
    108 
    109   // Set up darwin-specific properties.
    110   if (isDarwin())
    111     HasLazyResolverStubs = true;
    112 }
    113 
    114 /// SetJITMode - This is called to inform the subtarget info that we are
    115 /// producing code for the JIT.
    116 void PPCSubtarget::SetJITMode() {
    117   // JIT mode doesn't want lazy resolver stubs, it knows exactly where
    118   // everything is.  This matters for PPC64, which codegens in PIC mode without
    119   // stubs.
    120   HasLazyResolverStubs = false;
    121 
    122   // Calls to external functions need to use indirect calls
    123   IsJITCodeModel = true;
    124 }
    125 
    126 
    127 /// hasLazyResolverStub - Return true if accesses to the specified global have
    128 /// to go through a dyld lazy resolution stub.  This means that an extra load
    129 /// is required to get the address of the global.
    130 bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV,
    131                                        const TargetMachine &TM) const {
    132   // We never have stubs if HasLazyResolverStubs=false or if in static mode.
    133   if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
    134     return false;
    135   // If symbol visibility is hidden, the extra load is not needed if
    136   // the symbol is definitely defined in the current translation unit.
    137   bool isDecl = GV->isDeclaration() && !GV->isMaterializable();
    138   if (GV->hasHiddenVisibility() && !isDecl && !GV->hasCommonLinkage())
    139     return false;
    140   return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
    141          GV->hasCommonLinkage() || isDecl;
    142 }
    143