LLVM API Documentation

PPCSubtarget.cpp

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00001 //===- PowerPCSubtarget.cpp - PPC Subtarget Information -------------------===//
00002 //
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by Nate Begeman and is distributed under the
00006 // University of Illinois Open Source License. See LICENSE.TXT for details.
00007 //
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file implements the PPC specific subclass of TargetSubtarget.
00011 //
00012 //===----------------------------------------------------------------------===//
00013 
00014 #include "PPCSubtarget.h"
00015 #include "PPC.h"
00016 #include "llvm/Module.h"
00017 #include "PPCGenSubtarget.inc"
00018 #include <iostream>
00019 using namespace llvm;
00020 
00021 #if defined(__APPLE__)
00022 #include <mach/mach.h>
00023 #include <mach/mach_host.h>
00024 #include <mach/host_info.h>
00025 #include <mach/machine.h>
00026 
00027 /// GetCurrentPowerPCFeatures - Returns the current CPUs features.
00028 static const char *GetCurrentPowerPCCPU() {
00029   host_basic_info_data_t hostInfo;
00030   mach_msg_type_number_t infoCount;
00031 
00032   infoCount = HOST_BASIC_INFO_COUNT;
00033   host_info(mach_host_self(), HOST_BASIC_INFO, (host_info_t)&hostInfo, 
00034             &infoCount);
00035             
00036   if (hostInfo.cpu_type != CPU_TYPE_POWERPC) return "generic";
00037 
00038   switch(hostInfo.cpu_subtype) {
00039   case CPU_SUBTYPE_POWERPC_601:   return "601";
00040   case CPU_SUBTYPE_POWERPC_602:   return "602";
00041   case CPU_SUBTYPE_POWERPC_603:   return "603";
00042   case CPU_SUBTYPE_POWERPC_603e:  return "603e";
00043   case CPU_SUBTYPE_POWERPC_603ev: return "603ev";
00044   case CPU_SUBTYPE_POWERPC_604:   return "604";
00045   case CPU_SUBTYPE_POWERPC_604e:  return "604e";
00046   case CPU_SUBTYPE_POWERPC_620:   return "620";
00047   case CPU_SUBTYPE_POWERPC_750:   return "750";
00048   case CPU_SUBTYPE_POWERPC_7400:  return "7400";
00049   case CPU_SUBTYPE_POWERPC_7450:  return "7450";
00050   case CPU_SUBTYPE_POWERPC_970:   return "970";
00051   default: ;
00052   }
00053   
00054   return "generic";
00055 }
00056 #endif
00057 
00058 
00059 PPCSubtarget::PPCSubtarget(const Module &M, const std::string &FS, bool is64Bit)
00060   : StackAlignment(16)
00061   , InstrItins()
00062   , IsGigaProcessor(false)
00063   , Has64BitSupport(false)
00064   , Use64BitRegs(false)
00065   , IsPPC64(is64Bit)
00066   , HasAltivec(false)
00067   , HasFSQRT(false)
00068   , HasSTFIWX(false)
00069   , IsDarwin(false) {
00070 
00071   // Determine default and user specified characteristics
00072   std::string CPU = "generic";
00073 #if defined(__APPLE__)
00074   CPU = GetCurrentPowerPCCPU();
00075 #endif
00076 
00077   // Parse features string.
00078   ParseSubtargetFeatures(FS, CPU);
00079 
00080   // If we are generating code for ppc64, verify that options make sense.
00081   if (is64Bit) {
00082     if (!has64BitSupport()) {
00083       std::cerr << "PPC: Generation of 64-bit code for a 32-bit processor "
00084                    "requested.  Ignoring 32-bit processor feature.\n";
00085       Has64BitSupport = true;
00086     }
00087     // Silently force 64-bit register use on ppc64.
00088     Use64BitRegs = true;
00089   }
00090   
00091   // If the user requested use of 64-bit regs, but the cpu selected doesn't
00092   // support it, warn and ignore.
00093   if (use64BitRegs() && !has64BitSupport()) {
00094     std::cerr << "PPC: 64-bit registers requested on CPU without support.  "
00095                  "Disabling 64-bit register use.\n";
00096     Use64BitRegs = false;
00097   }
00098   
00099   // Set the boolean corresponding to the current target triple, or the default
00100   // if one cannot be determined, to true.
00101   const std::string& TT = M.getTargetTriple();
00102   if (TT.length() > 5) {
00103     IsDarwin = TT.find("-darwin") != std::string::npos;
00104   } else if (TT.empty()) {
00105 #if defined(__APPLE__)
00106     IsDarwin = true;
00107 #endif
00108   }
00109 }