1 //===-- PowerPCSubtarget.cpp - PPC Subtarget Information ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the PPC specific subclass of TargetSubtargetInfo.
12 //===----------------------------------------------------------------------===//
14 #include "PPCSubtarget.h"
15 #include "PPCRegisterInfo.h"
17 #include "llvm/GlobalValue.h"
18 #include "llvm/Target/TargetMachine.h"
19 #include "llvm/Support/Host.h"
20 #include "llvm/Support/TargetRegistry.h"
23 #define GET_SUBTARGETINFO_TARGET_DESC
24 #define GET_SUBTARGETINFO_CTOR
25 #include "PPCGenSubtargetInfo.inc"
29 PPCSubtarget::PPCSubtarget(const std::string &TT, const std::string &CPU,
30 const std::string &FS, bool is64Bit)
31 : PPCGenSubtargetInfo(TT, CPU, FS)
33 , DarwinDirective(PPC::DIR_NONE)
35 , Has64BitSupport(false)
42 , HasLazyResolverStubs(false)
43 , IsJITCodeModel(false)
46 // Determine default and user specified characteristics
47 std::string CPUName = CPU;
50 #if defined(__APPLE__) || \
51 (defined(__linux__) && (defined(__ppc__) || defined(__powerpc__)))
52 if (CPUName == "generic")
53 CPUName = sys::getHostCPUName();
56 // Parse features string.
57 ParseSubtargetFeatures(CPUName, FS);
59 // Initialize scheduling itinerary for the specified CPU.
60 InstrItins = getInstrItineraryForCPU(CPUName);
62 // If we are generating code for ppc64, verify that options make sense.
64 Has64BitSupport = true;
65 // Silently force 64-bit register use on ppc64.
69 // If the user requested use of 64-bit regs, but the cpu selected doesn't
70 // support it, ignore.
71 if (use64BitRegs() && !has64BitSupport())
74 // Set up darwin-specific properties.
76 HasLazyResolverStubs = true;
79 /// SetJITMode - This is called to inform the subtarget info that we are
80 /// producing code for the JIT.
81 void PPCSubtarget::SetJITMode() {
82 // JIT mode doesn't want lazy resolver stubs, it knows exactly where
83 // everything is. This matters for PPC64, which codegens in PIC mode without
85 HasLazyResolverStubs = false;
87 // Calls to external functions need to use indirect calls
88 IsJITCodeModel = true;
92 /// hasLazyResolverStub - Return true if accesses to the specified global have
93 /// to go through a dyld lazy resolution stub. This means that an extra load
94 /// is required to get the address of the global.
95 bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV,
96 const TargetMachine &TM) const {
97 // We never have stubs if HasLazyResolverStubs=false or if in static mode.
98 if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
100 // If symbol visibility is hidden, the extra load is not needed if
101 // the symbol is definitely defined in the current translation unit.
102 bool isDecl = GV->isDeclaration() && !GV->isMaterializable();
103 if (GV->hasHiddenVisibility() && !isDecl && !GV->hasCommonLinkage())
105 return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
106 GV->hasCommonLinkage() || isDecl;
109 bool PPCSubtarget::enablePostRAScheduler(
110 CodeGenOpt::Level OptLevel,
111 TargetSubtargetInfo::AntiDepBreakMode& Mode,
112 RegClassVector& CriticalPathRCs) const {
113 // FIXME: It would be best to use TargetSubtargetInfo::ANTIDEP_ALL here,
114 // but we can't because we can't reassign the cr registers. There is a
115 // dependence between the cr register and the RLWINM instruction used
116 // to extract its value which the anti-dependency breaker can't currently
117 // see. Maybe we should make a late-expanded pseudo to encode this dependency.
118 // (the relevant code is in PPCDAGToDAGISel::SelectSETCC)
120 Mode = TargetSubtargetInfo::ANTIDEP_CRITICAL;
122 CriticalPathRCs.clear();
125 CriticalPathRCs.push_back(&PPC::G8RCRegClass);
127 CriticalPathRCs.push_back(&PPC::GPRCRegClass);
129 CriticalPathRCs.push_back(&PPC::F8RCRegClass);
130 CriticalPathRCs.push_back(&PPC::VRRCRegClass);
132 return OptLevel >= CodeGenOpt::Default;