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/Module.h"
  17 #include "llvm/Target/TargetMachine.h"
  18 #include "PPCGenSubtarget.inc"
  19 using namespace llvm;
  20
  21 #if defined(__APPLE__)
  22 #include <mach/mach.h>
  23 #include <mach/mach_host.h>
  24 #include <mach/host_info.h>
  25 #include <mach/machine.h>
  26
  27 /// GetCurrentPowerPCFeatures - Returns the current CPUs features.
  28 static const char *GetCurrentPowerPCCPU() {
  29   host_basic_info_data_t hostInfo;
  30   mach_msg_type_number_t infoCount;
  31
  32   infoCount = HOST_BASIC_INFO_COUNT;
  33   host_info(mach_host_self(), HOST_BASIC_INFO, (host_info_t)&hostInfo,
  34             &infoCount);
  35
  36   if (hostInfo.cpu_type != CPU_TYPE_POWERPC) return "generic";
  37
  38   switch(hostInfo.cpu_subtype) {
  39   case CPU_SUBTYPE_POWERPC_601:   return "601";
  40   case CPU_SUBTYPE_POWERPC_602:   return "602";
  41   case CPU_SUBTYPE_POWERPC_603:   return "603";
  42   case CPU_SUBTYPE_POWERPC_603e:  return "603e";
  43   case CPU_SUBTYPE_POWERPC_603ev: return "603ev";
  44   case CPU_SUBTYPE_POWERPC_604:   return "604";
  45   case CPU_SUBTYPE_POWERPC_604e:  return "604e";
  46   case CPU_SUBTYPE_POWERPC_620:   return "620";
  47   case CPU_SUBTYPE_POWERPC_750:   return "750";
  48   case CPU_SUBTYPE_POWERPC_7400:  return "7400";
  49   case CPU_SUBTYPE_POWERPC_7450:  return "7450";
  50   case CPU_SUBTYPE_POWERPC_970:   return "970";
  51   default: ;
  52   }
  53
  54   return "generic";
  55 }
  56 #endif
  57
  58
  59 PPCSubtarget::PPCSubtarget(const TargetMachine &tm, const Module &M,
  60                            const std::string &FS, bool is64Bit)
  61   : TM(tm)
  62   , StackAlignment(16)
  63   , IsGigaProcessor(false)
  64   , Has64BitSupport(false)
  65   , Use64BitRegs(false)
  66   , IsPPC64(is64Bit)
  67   , HasAltivec(false)
  68   , HasFSQRT(false)
  69   , HasSTFIWX(false)
  70   , HasLazyResolverStubs(false)
  71   , DarwinVers(0) {
  72
  73   // Determine default and user specified characteristics
  74   std::string CPU = "generic";
  75 #if defined(__APPLE__)
  76   CPU = GetCurrentPowerPCCPU();
  77 #endif
  78
  79   // Parse features string.
  80   ParseSubtargetFeatures(FS, CPU);
  81
  82   // If we are generating code for ppc64, verify that options make sense.
  83   if (is64Bit) {
  84     if (!has64BitSupport()) {
  85       cerr << "PPC: Generation of 64-bit code for a 32-bit processor "
  86            << "requested.  Ignoring 32-bit processor feature.\n";
  87       Has64BitSupport = true;
  88     }
  89     // Silently force 64-bit register use on ppc64.
  90     Use64BitRegs = true;
  91   }
  92
  93   // If the user requested use of 64-bit regs, but the cpu selected doesn't
  94   // support it, warn and ignore.
  95   if (use64BitRegs() && !has64BitSupport()) {
  96     cerr << "PPC: 64-bit registers requested on CPU without support.  "
  97          << "Disabling 64-bit register use.\n";
  98     Use64BitRegs = false;
  99   }
 100
 101   // Set the boolean corresponding to the current target triple, or the default
 102   // if one cannot be determined, to true.
 103   const std::string &TT = M.getTargetTriple();
 104   if (TT.length() > 7) {
 105     // Determine which version of darwin this is.
 106     size_t DarwinPos = TT.find("-darwin");
 107     if (DarwinPos != std::string::npos) {
 108       if (isdigit(TT[DarwinPos+7]))
 109         DarwinVers = atoi(&TT[DarwinPos+7]);
 110       else
 111         DarwinVers = 8;  // Minimum supported darwin is Tiger.
 112     }
 113   } else if (TT.empty()) {
 114     // Try to autosense the subtarget from the host compiler.
 115 #if defined(__APPLE__)
 116 #if __APPLE_CC__ > 5400
 117     DarwinVers = 9;  // GCC 5400+ is Leopard.
 118 #else
 119     DarwinVers = 8;  // Minimum supported darwin is Tiger.
 120 #endif
 121 #endif
 122   }
 123
 124   // Set up darwin-specific properties.
 125   if (isDarwin()) {
 126     HasLazyResolverStubs = true;
 127     AsmFlavor = NewMnemonic;
 128   } else {
 129     AsmFlavor = OldMnemonic;
 130   }
 131 }
 132
 133 /// SetJITMode - This is called to inform the subtarget info that we are
 134 /// producing code for the JIT.
 135 void PPCSubtarget::SetJITMode() {
 136   // JIT mode doesn't want lazy resolver stubs, it knows exactly where
 137   // everything is.  This matters for PPC64, which codegens in PIC mode without
 138   // stubs.
 139   HasLazyResolverStubs = false;
 140 }
 141
 142
 143 /// hasLazyResolverStub - Return true if accesses to the specified global have
 144 /// to go through a dyld lazy resolution stub.  This means that an extra load
 145 /// is required to get the address of the global.
 146 bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV) const {
 147   // We never hae stubs if HasLazyResolverStubs=false or if in static mode.
 148   if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
 149     return false;
 150
 151   return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
 152          (GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode());
 153 }