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)
43 , HasLazyResolverStubs(false)
44 , IsJITCodeModel(false)
47 // Determine default and user specified characteristics
48 std::string CPUName = CPU;
51 #if (defined(__APPLE__) || defined(__linux__)) && \
52 (defined(__ppc__) || defined(__powerpc__))
53 if (CPUName == "generic")
54 CPUName = sys::getHostCPUName();
57 // Parse features string.
58 ParseSubtargetFeatures(CPUName, FS);
60 // Initialize scheduling itinerary for the specified CPU.
61 InstrItins = getInstrItineraryForCPU(CPUName);
63 // If we are generating code for ppc64, verify that options make sense.
65 Has64BitSupport = true;
66 // Silently force 64-bit register use on ppc64.
70 // If the user requested use of 64-bit regs, but the cpu selected doesn't
71 // support it, ignore.
72 if (use64BitRegs() && !has64BitSupport())
75 // Set up darwin-specific properties.
77 HasLazyResolverStubs = true;
80 /// SetJITMode - This is called to inform the subtarget info that we are
81 /// producing code for the JIT.
82 void PPCSubtarget::SetJITMode() {
83 // JIT mode doesn't want lazy resolver stubs, it knows exactly where
84 // everything is. This matters for PPC64, which codegens in PIC mode without
86 HasLazyResolverStubs = false;
88 // Calls to external functions need to use indirect calls
89 IsJITCodeModel = true;
93 /// hasLazyResolverStub - Return true if accesses to the specified global have
94 /// to go through a dyld lazy resolution stub. This means that an extra load
95 /// is required to get the address of the global.
96 bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV,
97 const TargetMachine &TM) const {
98 // We never have stubs if HasLazyResolverStubs=false or if in static mode.
99 if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
101 // If symbol visibility is hidden, the extra load is not needed if
102 // the symbol is definitely defined in the current translation unit.
103 bool isDecl = GV->isDeclaration() && !GV->isMaterializable();
104 if (GV->hasHiddenVisibility() && !isDecl && !GV->hasCommonLinkage())
106 return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
107 GV->hasCommonLinkage() || isDecl;
110 bool PPCSubtarget::enablePostRAScheduler(
111 CodeGenOpt::Level OptLevel,
112 TargetSubtargetInfo::AntiDepBreakMode& Mode,
113 RegClassVector& CriticalPathRCs) const {
114 // FIXME: It would be best to use TargetSubtargetInfo::ANTIDEP_ALL here,
115 // but we can't because we can't reassign the cr registers. There is a
116 // dependence between the cr register and the RLWINM instruction used
117 // to extract its value which the anti-dependency breaker can't currently
118 // see. Maybe we should make a late-expanded pseudo to encode this dependency.
119 // (the relevant code is in PPCDAGToDAGISel::SelectSETCC)
121 Mode = TargetSubtargetInfo::ANTIDEP_CRITICAL;
123 CriticalPathRCs.clear();
126 CriticalPathRCs.push_back(&PPC::G8RCRegClass);
128 CriticalPathRCs.push_back(&PPC::GPRCRegClass);
130 CriticalPathRCs.push_back(&PPC::F8RCRegClass);
131 CriticalPathRCs.push_back(&PPC::VRRCRegClass);
133 return OptLevel >= CodeGenOpt::Default;