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      1 //===-- SystemZSubtarget.cpp - SystemZ 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 #include "SystemZSubtarget.h"
     11 #include "MCTargetDesc/SystemZMCTargetDesc.h"
     12 #include "llvm/IR/GlobalValue.h"
     13 #include "llvm/Support/Host.h"
     14 
     15 using namespace llvm;
     16 
     17 #define DEBUG_TYPE "systemz-subtarget"
     18 
     19 #define GET_SUBTARGETINFO_TARGET_DESC
     20 #define GET_SUBTARGETINFO_CTOR
     21 #include "SystemZGenSubtargetInfo.inc"
     22 
     23 // Pin the vtable to this file.
     24 void SystemZSubtarget::anchor() {}
     25 
     26 SystemZSubtarget &
     27 SystemZSubtarget::initializeSubtargetDependencies(StringRef CPU, StringRef FS) {
     28   std::string CPUName = CPU;
     29   if (CPUName.empty())
     30     CPUName = "generic";
     31 #if defined(__linux__) && defined(__s390x__)
     32   if (CPUName == "generic")
     33     CPUName = sys::getHostCPUName();
     34 #endif
     35   // Parse features string.
     36   ParseSubtargetFeatures(CPUName, FS);
     37   return *this;
     38 }
     39 
     40 SystemZSubtarget::SystemZSubtarget(const std::string &TT,
     41                                    const std::string &CPU,
     42                                    const std::string &FS,
     43                                    const TargetMachine &TM)
     44     : SystemZGenSubtargetInfo(TT, CPU, FS), HasDistinctOps(false),
     45       HasLoadStoreOnCond(false), HasHighWord(false), HasFPExtension(false),
     46       HasFastSerialization(false), HasInterlockedAccess1(false),
     47       TargetTriple(TT),
     48       // Make sure that global data has at least 16 bits of alignment by
     49       // default, so that we can refer to it using LARL.  We don't have any
     50       // special requirements for stack variables though.
     51       DL("E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-a:8:16-n32:64"),
     52       InstrInfo(initializeSubtargetDependencies(CPU, FS)), TLInfo(TM),
     53       TSInfo(DL), FrameLowering() {}
     54 
     55 // Return true if GV binds locally under reloc model RM.
     56 static bool bindsLocally(const GlobalValue *GV, Reloc::Model RM) {
     57   // For non-PIC, all symbols bind locally.
     58   if (RM == Reloc::Static)
     59     return true;
     60 
     61   return GV->hasLocalLinkage() || !GV->hasDefaultVisibility();
     62 }
     63 
     64 bool SystemZSubtarget::isPC32DBLSymbol(const GlobalValue *GV,
     65                                        Reloc::Model RM,
     66                                        CodeModel::Model CM) const {
     67   // PC32DBL accesses require the low bit to be clear.  Note that a zero
     68   // value selects the default alignment and is therefore OK.
     69   if (GV->getAlignment() == 1)
     70     return false;
     71 
     72   // For the small model, all locally-binding symbols are in range.
     73   if (CM == CodeModel::Small)
     74     return bindsLocally(GV, RM);
     75 
     76   // For Medium and above, assume that the symbol is not within the 4GB range.
     77   // Taking the address of locally-defined text would be OK, but that
     78   // case isn't easy to detect.
     79   return false;
     80 }
     81