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/Support/TargetRegistry.h"
19 #include <cstdlib>
20
21 #define GET_SUBTARGETINFO_TARGET_DESC
22 #define GET_SUBTARGETINFO_CTOR
23 #include "PPCGenSubtargetInfo.inc"
24
25 using 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.
GetCurrentPowerPCCPU()34 static 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
PPCSubtarget(const std::string & TT,const std::string & CPU,const std::string & FS,bool is64Bit)65 PPCSubtarget::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.
SetJITMode()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 // 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.
hasLazyResolverStub(const GlobalValue * GV,const TargetMachine & TM) const129 bool 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