PPCSubtarget.cpp revision 203954
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> 20using 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. 29static 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 60PPCSubtarget::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. 115void 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. 126bool 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->isMaterializable(); 134 if (GV->hasHiddenVisibility() && !isDecl && !GV->hasCommonLinkage()) 135 return false; 136 return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() || 137 GV->hasCommonLinkage() || isDecl; 138} 139