PPCSubtarget.cpp revision c60f9b752381baa6c4b80c0739034660f1748c84 
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/Target/TargetRegistry.h"
19#include <cstdlib>
20
21#define GET_SUBTARGETINFO_TARGET_DESC
22#define GET_SUBTARGETINFO_CTOR
23#include "PPCGenSubtargetInfo.inc"
24
25using 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.
34static 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
65PPCSubtarget::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  , HasLazyResolverStubs(false)
78  , IsJITCodeModel(false)
79  , TargetTriple(TT) {
80
81  // Determine default and user specified characteristics
82  std::string CPUName = CPU;
83  if (CPUName.empty())
84    CPUName = "generic";
85#if defined(__APPLE__)
86  if (CPUName == "generic")
87    CPUName = GetCurrentPowerPCCPU();
88#endif
89
90  // Parse features string.
91  ParseSubtargetFeatures(CPUName, FS);
92
93  // Initialize scheduling itinerary for the specified CPU.
94  InstrItins = getInstrItineraryForCPU(CPUName);
95
96  // If we are generating code for ppc64, verify that options make sense.
97  if (is64Bit) {
98    Has64BitSupport = true;
99    // Silently force 64-bit register use on ppc64.
100    Use64BitRegs = true;
101  }
102
103  // If the user requested use of 64-bit regs, but the cpu selected doesn't
104  // support it, ignore.
105  if (use64BitRegs() && !has64BitSupport())
106    Use64BitRegs = false;
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  // Calls to external functions need to use indirect calls
122  IsJITCodeModel = true;
123}
124
125
126/// hasLazyResolverStub - Return true if accesses to the specified global have
127/// to go through a dyld lazy resolution stub.  This means that an extra load
128/// is required to get the address of the global.
129bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV,
130                                       const TargetMachine &TM) const {
131  // We never have stubs if HasLazyResolverStubs=false or if in static mode.
132  if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
133    return false;
134  // If symbol visibility is hidden, the extra load is not needed if
135  // the symbol is definitely defined in the current translation unit.
136  bool isDecl = GV->isDeclaration() && !GV->isMaterializable();
137  if (GV->hasHiddenVisibility() && !isDecl && !GV->hasCommonLinkage())
138    return false;
139  return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
140         GV->hasCommonLinkage() || isDecl;
141}
142