lib/Target/PowerPC/PPCSubtarget.cpp

   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 TargetSubtarget.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "PPCSubtarget.h"
  15 #include "PPC.h"
  16 #include "llvm/GlobalValue.h"
  17 #include "llvm/Target/TargetMachine.h"
  18 #include "PPCGenSubtarget.inc"
  19 #include <cstdlib>
  20 using namespace llvm;
  21
  22 #if defined(__APPLE__)
  23 #include <mach/mach.h>
  24 #include <mach/mach_host.h>
  25 #include <mach/host_info.h>
  26 #include <mach/machine.h>
  27
  28 /// GetCurrentPowerPCFeatures - Returns the current CPUs features.
  29 static const char *GetCurrentPowerPCCPU() {
  30   host_basic_info_data_t hostInfo;
  31   mach_msg_type_number_t infoCount;
  32
  33   infoCount = HOST_BASIC_INFO_COUNT;
  34   host_info(mach_host_self(), HOST_BASIC_INFO, (host_info_t)&hostInfo,
  35             &infoCount);
  36
  37   if (hostInfo.cpu_type != CPU_TYPE_POWERPC) return "generic";
  38
  39   switch(hostInfo.cpu_subtype) {
  40   case CPU_SUBTYPE_POWERPC_601:   return "601";
  41   case CPU_SUBTYPE_POWERPC_602:   return "602";
  42   case CPU_SUBTYPE_POWERPC_603:   return "603";
  43   case CPU_SUBTYPE_POWERPC_603e:  return "603e";
  44   case CPU_SUBTYPE_POWERPC_603ev: return "603ev";
  45   case CPU_SUBTYPE_POWERPC_604:   return "604";
  46   case CPU_SUBTYPE_POWERPC_604e:  return "604e";
  47   case CPU_SUBTYPE_POWERPC_620:   return "620";
  48   case CPU_SUBTYPE_POWERPC_750:   return "750";
  49   case CPU_SUBTYPE_POWERPC_7400:  return "7400";
  50   case CPU_SUBTYPE_POWERPC_7450:  return "7450";
  51   case CPU_SUBTYPE_POWERPC_970:   return "970";
  52   default: ;
  53   }
  54
  55   return "generic";
  56 }
  57 #endif
  58
  59
  60 PPCSubtarget::PPCSubtarget(const std::string &TT, const std::string &FS,
  61                            bool is64Bit)
  62   : StackAlignment(16)
  63   , DarwinDirective(PPC::DIR_NONE)
  64   , IsGigaProcessor(false)
  65   , Has64BitSupport(false)
  66   , Use64BitRegs(false)
  67   , IsPPC64(is64Bit)
  68   , HasAltivec(false)
  69   , HasFSQRT(false)
  70   , HasSTFIWX(false)
  71   , HasLazyResolverStubs(false)
  72   , DarwinVers(0) {
  73
  74   // Determine default and user specified characteristics
  75   std::string CPU = "generic";
  76 #if defined(__APPLE__)
  77   CPU = GetCurrentPowerPCCPU();
  78 #endif
  79
  80   // Parse features string.
  81   ParseSubtargetFeatures(FS, CPU);
  82
  83   // If we are generating code for ppc64, verify that options make sense.
  84   if (is64Bit) {
  85     Has64BitSupport = true;
  86     // Silently force 64-bit register use on ppc64.
  87     Use64BitRegs = true;
  88   }
  89
  90   // If the user requested use of 64-bit regs, but the cpu selected doesn't
  91   // support it, ignore.
  92   if (use64BitRegs() && !has64BitSupport())
  93     Use64BitRegs = false;
  94
  95   // Set the boolean corresponding to the current target triple, or the default
  96   // if one cannot be determined, to true.
  97   if (TT.length() > 7) {
  98     // Determine which version of darwin this is.
  99     size_t DarwinPos = TT.find("-darwin");
 100     if (DarwinPos != std::string::npos) {
 101       if (isdigit(TT[DarwinPos+7]))
 102         DarwinVers = atoi(&TT[DarwinPos+7]);
 103       else
 104         DarwinVers = 8;  // Minimum supported darwin is Tiger.
 105     }
 106   }
 107
 108   // Set up darwin-specific properties.
 109   if (isDarwin())
 110     HasLazyResolverStubs = true;
 111 }
 112
 113 /// SetJITMode - This is called to inform the subtarget info that we are
 114 /// producing code for the JIT.
 115 void PPCSubtarget::SetJITMode() {
 116   // JIT mode doesn't want lazy resolver stubs, it knows exactly where
 117   // everything is.  This matters for PPC64, which codegens in PIC mode without
 118   // stubs.
 119   HasLazyResolverStubs = false;
 120 }
 121
 122
 123 /// hasLazyResolverStub - Return true if accesses to the specified global have
 124 /// to go through a dyld lazy resolution stub.  This means that an extra load
 125 /// is required to get the address of the global.
 126 bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV,
 127                                        const TargetMachine &TM) const {
 128   // We never hae stubs if HasLazyResolverStubs=false or if in static mode.
 129   if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
 130     return false;
 131   // If symbol visibility is hidden, the extra load is not needed if
 132   // the symbol is definitely defined in the current translation unit.
 133   bool isDecl = GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode();
 134   if (GV->hasHiddenVisibility() && !isDecl && !GV->hasCommonLinkage())
 135     return false;
 136   return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
 137          GV->hasCommonLinkage() || isDecl;
 138 }