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), InstrInfo(initializeSubtargetDependencies(CPU, FS)),
48       TLInfo(TM, *this), TSInfo(*TM.getDataLayout()), FrameLowering() {}
49 
50 // Return true if GV binds locally under reloc model RM.
51 static bool bindsLocally(const GlobalValue *GV, Reloc::Model RM) {
52   // For non-PIC, all symbols bind locally.
53   if (RM == Reloc::Static)
54     return true;
55 
56   return GV->hasLocalLinkage() || !GV->hasDefaultVisibility();
57 }
58 
59 bool SystemZSubtarget::isPC32DBLSymbol(const GlobalValue *GV,
60                                        Reloc::Model RM,
61                                        CodeModel::Model CM) const {
62   // PC32DBL accesses require the low bit to be clear.  Note that a zero
63   // value selects the default alignment and is therefore OK.
64   if (GV->getAlignment() == 1)
65     return false;
66 
67   // For the small model, all locally-binding symbols are in range.
68   if (CM == CodeModel::Small)
69     return bindsLocally(GV, RM);
70 
71   // For Medium and above, assume that the symbol is not within the 4GB range.
72   // Taking the address of locally-defined text would be OK, but that
73   // case isn't easy to detect.
74   return false;
75 }
76