HexagonTargetObjectFile.cpp revision 234285
1234285Sdim//===-- HexagonTargetObjectFile.cpp - Hexagon asm properties --------------===//
2234285Sdim//
3234285Sdim//                     The LLVM Compiler Infrastructure
4234285Sdim//
5234285Sdim// This file is distributed under the University of Illinois Open Source
6234285Sdim// License. See LICENSE.TXT for details.
7234285Sdim//
8234285Sdim//===----------------------------------------------------------------------===//
9234285Sdim//
10234285Sdim// This file contains the declarations of the HexagonTargetAsmInfo properties.
11234285Sdim//
12234285Sdim//===----------------------------------------------------------------------===//
13234285Sdim
14234285Sdim#include "HexagonTargetObjectFile.h"
15234285Sdim#include "HexagonSubtarget.h"
16234285Sdim#include "HexagonTargetMachine.h"
17234285Sdim#include "llvm/Function.h"
18234285Sdim#include "llvm/GlobalVariable.h"
19234285Sdim#include "llvm/Target/TargetData.h"
20234285Sdim#include "llvm/DerivedTypes.h"
21234285Sdim#include "llvm/MC/MCContext.h"
22234285Sdim#include "llvm/Support/ELF.h"
23234285Sdim#include "llvm/Support/CommandLine.h"
24234285Sdim
25234285Sdimusing namespace llvm;
26234285Sdim
27234285Sdimstatic cl::opt<int> SmallDataThreshold("hexagon-small-data-threshold",
28234285Sdim                                cl::init(8), cl::Hidden);
29234285Sdim
30234285Sdimvoid HexagonTargetObjectFile::Initialize(MCContext &Ctx,
31234285Sdim                                         const TargetMachine &TM) {
32234285Sdim  TargetLoweringObjectFileELF::Initialize(Ctx, TM);
33234285Sdim
34234285Sdim
35234285Sdim  SmallDataSection =
36234285Sdim    getContext().getELFSection(".sdata", ELF::SHT_PROGBITS,
37234285Sdim                               ELF::SHF_WRITE | ELF::SHF_ALLOC,
38234285Sdim                               SectionKind::getDataRel());
39234285Sdim  SmallBSSSection =
40234285Sdim    getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
41234285Sdim                               ELF::SHF_WRITE | ELF::SHF_ALLOC,
42234285Sdim                               SectionKind::getBSS());
43234285Sdim}
44234285Sdim
45234285Sdim// sdata/sbss support taken largely from the MIPS Backend.
46234285Sdimstatic bool IsInSmallSection(uint64_t Size) {
47234285Sdim  return Size > 0 && Size <= (uint64_t)SmallDataThreshold;
48234285Sdim}
49234285Sdim/// IsGlobalInSmallSection - Return true if this global value should be
50234285Sdim/// placed into small data/bss section.
51234285Sdimbool HexagonTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,
52234285Sdim                                                const TargetMachine &TM) const {
53234285Sdim  // If the primary definition of this global value is outside the current
54234285Sdim  // translation unit or the global value is available for inspection but not
55234285Sdim  // emission, then do nothing.
56234285Sdim  if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
57234285Sdim    return false;
58234285Sdim
59234285Sdim  // Otherwise, Check if GV should be in sdata/sbss, when normally it would end
60234285Sdim  // up in getKindForGlobal(GV, TM).
61234285Sdim  return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM));
62234285Sdim}
63234285Sdim
64234285Sdim/// IsGlobalInSmallSection - Return true if this global value should be
65234285Sdim/// placed into small data/bss section.
66234285Sdimbool HexagonTargetObjectFile::
67234285SdimIsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM,
68234285Sdim                       SectionKind Kind) const {
69234285Sdim  // Only global variables, not functions.
70234285Sdim  const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
71234285Sdim  if (!GVA)
72234285Sdim    return false;
73234285Sdim
74234285Sdim  if (Kind.isBSS() || Kind.isDataNoRel() || Kind.isCommon()) {
75234285Sdim    Type *Ty = GV->getType()->getElementType();
76234285Sdim    return IsInSmallSection(TM.getTargetData()->getTypeAllocSize(Ty));
77234285Sdim  }
78234285Sdim
79234285Sdim  return false;
80234285Sdim}
81234285Sdim
82234285Sdimconst MCSection *HexagonTargetObjectFile::
83234285SdimSelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
84234285Sdim                       Mangler *Mang, const TargetMachine &TM) const {
85234285Sdim
86234285Sdim  // Handle Small Section classification here.
87234285Sdim  if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind))
88234285Sdim    return SmallBSSSection;
89234285Sdim  if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind))
90234285Sdim    return SmallDataSection;
91234285Sdim
92234285Sdim  // Otherwise, we work the same as ELF.
93234285Sdim  return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM);
94234285Sdim}
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