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llvm-mirror/lib/Target/MBlaze/MBlazeTargetObjectFile.cpp
Wesley Peck 94cdac52e5 Adding the MicroBlaze backend.
The MicroBlaze is a highly configurable 32-bit soft-microprocessor for
use on Xilinx FPGAs. For more information see:
http://www.xilinx.com/tools/microblaze.htm
http://en.wikipedia.org/wiki/MicroBlaze

The current LLVM MicroBlaze backend generates assembly which can be
compiled using the an appropriate binutils assembler.

llvm-svn: 96969
2010-02-23 19:15:24 +00:00

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3.0 KiB
C++

//===-- MBlazeTargetObjectFile.cpp - MBlaze object files ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "MBlazeTargetObjectFile.h"
#include "MBlazeSubtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalVariable.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
void MBlazeTargetObjectFile::
Initialize(MCContext &Ctx, const TargetMachine &TM) {
TargetLoweringObjectFileELF::Initialize(Ctx, TM);
SmallDataSection =
getELFSection(".sdata", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
SectionKind::getDataRel());
SmallBSSSection =
getELFSection(".sbss", MCSectionELF::SHT_NOBITS,
MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
SectionKind::getBSS());
}
// A address must be loaded from a small section if its size is less than the
// small section size threshold. Data in this section must be addressed using
// gp_rel operator.
static bool IsInSmallSection(uint64_t Size) {
return Size > 0 && Size <= 8;
}
bool MBlazeTargetObjectFile::
IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM) const {
if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
return false;
return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM));
}
/// IsGlobalInSmallSection - Return true if this global address should be
/// placed into small data/bss section.
bool MBlazeTargetObjectFile::
IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM,
SectionKind Kind) const {
// Only global variables, not functions.
const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
if (!GVA)
return false;
// We can only do this for datarel or BSS objects for now.
if (!Kind.isBSS() && !Kind.isDataRel())
return false;
// If this is a internal constant string, there is a special
// section for it, but not in small data/bss.
if (Kind.isMergeable1ByteCString())
return false;
const Type *Ty = GV->getType()->getElementType();
return IsInSmallSection(TM.getTargetData()->getTypeAllocSize(Ty));
}
const MCSection *MBlazeTargetObjectFile::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
// TODO: Could also support "weak" symbols as well with ".gnu.linkonce.s.*"
// sections?
// Handle Small Section classification here.
if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind))
return SmallBSSSection;
if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind))
return SmallDataSection;
// Otherwise, we work the same as ELF.
return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM);
}