llvm-6502/lib/Target/XCore/XCoreTargetAsmInfo.cpp
Duncan Sands 667d4b8de6 Introduce new linkage types linkonce_odr, weak_odr, common_odr
and extern_weak_odr.  These are the same as the non-odr versions,
except that they indicate that the global will only be overridden
by an *equivalent* global.  In C, a function with weak linkage can
be overridden by a function which behaves completely differently.
This means that IP passes have to skip weak functions, since any
deductions made from the function definition might be wrong, since
the definition could be replaced by something completely different
at link time.   This is not allowed in C++, thanks to the ODR
(One-Definition-Rule): if a function is replaced by another at
link-time, then the new function must be the same as the original
function.  If a language knows that a function or other global can
only be overridden by an equivalent global, it can give it the
weak_odr linkage type, and the optimizers will understand that it
is alright to make deductions based on the function body.  The
code generators on the other hand map weak and weak_odr linkage
to the same thing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66339 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-07 15:45:40 +00:00

202 lines
6.4 KiB
C++

//===-- XCoreTargetAsmInfo.cpp - XCore asm properties -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declarations of the XCoreTargetAsmInfo properties.
// We use the small section flag for the CP relative and DP relative
// flags. If a section is small and writable then it is DP relative. If a
// section is small and not writable then it is CP relative.
//
//===----------------------------------------------------------------------===//
#include "XCoreTargetAsmInfo.h"
#include "XCoreTargetMachine.h"
#include "llvm/GlobalVariable.h"
#include "llvm/ADT/StringExtras.h"
using namespace llvm;
XCoreTargetAsmInfo::XCoreTargetAsmInfo(const XCoreTargetMachine &TM)
: ELFTargetAsmInfo(TM),
Subtarget(TM.getSubtargetImpl()) {
TextSection = getUnnamedSection("\t.text", SectionFlags::Code);
DataSection = getNamedSection("\t.dp.data", SectionFlags::Writeable |
SectionFlags::Small);
BSSSection_ = getNamedSection("\t.dp.bss", SectionFlags::Writeable |
SectionFlags::BSS | SectionFlags::Small);
if (Subtarget->isXS1A()) {
ReadOnlySection = getNamedSection("\t.dp.rodata", SectionFlags::None |
SectionFlags::Writeable |
SectionFlags::Small);
} else {
ReadOnlySection = getNamedSection("\t.cp.rodata", SectionFlags::None |
SectionFlags::Small);
}
Data16bitsDirective = "\t.short\t";
Data32bitsDirective = "\t.long\t";
Data64bitsDirective = 0;
ZeroDirective = "\t.space\t";
CommentString = "#";
ConstantPoolSection = "\t.section\t.cp.rodata,\"ac\",@progbits";
JumpTableDataSection = "\t.section\t.dp.data,\"awd\",@progbits";
PrivateGlobalPrefix = ".L";
AscizDirective = ".asciiz";
WeakDefDirective = "\t.weak\t";
WeakRefDirective = "\t.weak\t";
SetDirective = "\t.set\t";
// Debug
HasLEB128 = true;
AbsoluteDebugSectionOffsets = true;
DwarfAbbrevSection = "\t.section\t.debug_abbrev,\"\",@progbits";
DwarfInfoSection = "\t.section\t.debug_info,\"\",@progbits";
DwarfLineSection = "\t.section\t.debug_line,\"\",@progbits";
DwarfFrameSection = "\t.section\t.debug_frame,\"\",@progbits";
DwarfPubNamesSection = "\t.section\t.debug_pubnames,\"\",@progbits";
DwarfPubTypesSection = "\t.section\t.debug_pubtypes,\"\",@progbits";
DwarfStrSection = "\t.section\t.debug_str,\"\",@progbits";
DwarfLocSection = "\t.section\t.debug_loc,\"\",@progbits";
DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
DwarfRangesSection = "\t.section\t.debug_ranges,\"\",@progbits";
DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
}
const Section*
XCoreTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
SectionKind::Kind Kind = SectionKindForGlobal(GV);
if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
{
if (!GVar->isWeakForLinker()) {
switch (Kind) {
case SectionKind::RODataMergeStr:
return MergeableStringSection(GVar);
case SectionKind::RODataMergeConst:
return getReadOnlySection();
case SectionKind::ThreadData:
return DataSection;
case SectionKind::ThreadBSS:
return getBSSSection_();
default:
break;
}
}
}
return ELFTargetAsmInfo::SelectSectionForGlobal(GV);
}
const Section*
XCoreTargetAsmInfo::SelectSectionForMachineConst(const Type *Ty) const {
return MergeableConstSection(Ty);
}
const Section*
XCoreTargetAsmInfo::MergeableConstSection(const GlobalVariable *GV) const {
Constant *C = GV->getInitializer();
return MergeableConstSection(C->getType());
}
inline const Section*
XCoreTargetAsmInfo::MergeableConstSection(const Type *Ty) const {
const TargetData *TD = TM.getTargetData();
unsigned Size = TD->getTypePaddedSize(Ty);
if (Size == 4 || Size == 8 || Size == 16) {
std::string Name = ".cp.const" + utostr(Size);
return getNamedSection(Name.c_str(),
SectionFlags::setEntitySize(SectionFlags::Mergeable |
SectionFlags::Small,
Size));
}
return getReadOnlySection();
}
const Section* XCoreTargetAsmInfo::
MergeableStringSection(const GlobalVariable *GV) const {
// FIXME insert in correct mergable section
return getReadOnlySection();
}
unsigned XCoreTargetAsmInfo::
SectionFlagsForGlobal(const GlobalValue *GV,
const char* Name) const {
unsigned Flags = ELFTargetAsmInfo::SectionFlagsForGlobal(GV, Name);
// Mask out unsupported flags
Flags &= ~(SectionFlags::Small | SectionFlags::TLS);
// Set CP / DP relative flags
if (GV) {
SectionKind::Kind Kind = SectionKindForGlobal(GV);
switch (Kind) {
case SectionKind::ThreadData:
case SectionKind::ThreadBSS:
case SectionKind::Data:
case SectionKind::BSS:
case SectionKind::SmallData:
case SectionKind::SmallBSS:
Flags |= SectionFlags::Small;
break;
case SectionKind::ROData:
case SectionKind::RODataMergeStr:
case SectionKind::SmallROData:
if (Subtarget->isXS1A()) {
Flags |= SectionFlags::Writeable;
}
Flags |=SectionFlags::Small;
break;
case SectionKind::RODataMergeConst:
Flags |=SectionFlags::Small;
default:
break;
}
}
return Flags;
}
std::string XCoreTargetAsmInfo::
printSectionFlags(unsigned flags) const {
std::string Flags = ",\"";
if (!(flags & SectionFlags::Debug))
Flags += 'a';
if (flags & SectionFlags::Code)
Flags += 'x';
if (flags & SectionFlags::Writeable)
Flags += 'w';
if (flags & SectionFlags::Mergeable)
Flags += 'M';
if (flags & SectionFlags::Strings)
Flags += 'S';
if (flags & SectionFlags::TLS)
Flags += 'T';
if (flags & SectionFlags::Small) {
if (flags & SectionFlags::Writeable)
Flags += 'd'; // DP relative
else
Flags += 'c'; // CP relative
}
Flags += "\",";
Flags += '@';
if (flags & SectionFlags::BSS)
Flags += "nobits";
else
Flags += "progbits";
if (unsigned entitySize = SectionFlags::getEntitySize(flags))
Flags += "," + utostr(entitySize);
return Flags;
}