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Tony Linthicumb4b54152011-12-12 21:14:40 +00001//===-- HexagonTargetObjectFile.cpp - Hexagon asm properties ----*- C++ -*-===//
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// This file contains the declarations of the HexagonTargetAsmInfo properties.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Function.h"
15#include "llvm/GlobalVariable.h"
16#include "llvm/Target/TargetData.h"
17#include "llvm/DerivedTypes.h"
18#include "llvm/MC/MCContext.h"
19#include "llvm/Support/ELF.h"
20#include "llvm/Support/CommandLine.h"
21#include "HexagonSubtarget.h"
22#include "HexagonTargetObjectFile.h"
23#include "HexagonTargetMachine.h"
24
25using namespace llvm;
26
27static cl::opt<int> SmallDataThreshold("hexagon-small-data-threshold",
28 cl::init(8), cl::Hidden);
29
30void HexagonTargetObjectFile::Initialize(MCContext &Ctx,
31 const TargetMachine &TM) {
32 TargetLoweringObjectFileELF::Initialize(Ctx, TM);
33
34
35 SmallDataSection =
36 getContext().getELFSection(".sdata", ELF::SHT_PROGBITS,
37 ELF::SHF_WRITE | ELF::SHF_ALLOC,
38 SectionKind::getDataRel());
39 SmallBSSSection =
40 getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
41 ELF::SHF_WRITE | ELF::SHF_ALLOC,
42 SectionKind::getBSS());
43}
44
45// sdata/sbss support taken largely from the MIPS Backend.
46static bool IsInSmallSection(uint64_t Size) {
47 return Size > 0 && Size <= (uint64_t)SmallDataThreshold;
48}
49/// IsGlobalInSmallSection - Return true if this global value should be
50/// placed into small data/bss section.
51bool HexagonTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,
52 const TargetMachine &TM) const {
53 // If the primary definition of this global value is outside the current
54 // translation unit or the global value is available for inspection but not
55 // emission, then do nothing.
56 if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
57 return false;
58
59 // Otherwise, Check if GV should be in sdata/sbss, when normally it would end
60 // up in getKindForGlobal(GV, TM).
61 return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM));
62}
63
64/// IsGlobalInSmallSection - Return true if this global value should be
65/// placed into small data/bss section.
66bool HexagonTargetObjectFile::
67IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM,
68 SectionKind Kind) const {
69 // Only global variables, not functions.
70 const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
71 if (!GVA)
72 return false;
73
74 if (Kind.isBSS() || Kind.isDataNoRel() || Kind.isCommon()) {
75 Type *Ty = GV->getType()->getElementType();
76 return IsInSmallSection(TM.getTargetData()->getTypeAllocSize(Ty));
77 }
78
79 return false;
80}
81
82const MCSection *HexagonTargetObjectFile::
83SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
84 Mangler *Mang, const TargetMachine &TM) const {
85
86 // Handle Small Section classification here.
87 if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind))
88 return SmallBSSSection;
89 if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind))
90 return SmallDataSection;
91
92 // Otherwise, we work the same as ELF.
93 return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM);
94}