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echristoechristo
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Add support for allowing us to create uniquely identified "COMDAT" or "ELF
Group" sections while lowering. In particular, for ELF sections this is useful for creating function-specific groups that get merged into the same named section. Also use const Twine& instead of StringRef for the getELF functions while we're here. Differential Revision: http://reviews.llvm.org/D21743 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274336 91177308-0d34-0410-b5e6-96231b3b80d8
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3 files changed

+37
-23
lines changed

3 files changed

+37
-23
lines changed

‎include/llvm/MC/MCContext.h

Lines changed: 20 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -339,48 +339,56 @@ namespace llvm {
339339
BeginSymName);
340340
}
341341

342-
MCSectionELF *getELFSection(StringRef Section, unsigned Type,
342+
MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
343343
unsigned Flags) {
344344
return getELFSection(Section, Type, Flags, nullptr);
345345
}
346346

347-
MCSectionELF *getELFSection(StringRef Section, unsigned Type,
347+
MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
348348
unsigned Flags, const char *BeginSymName) {
349349
return getELFSection(Section, Type, Flags, 0, "", BeginSymName);
350350
}
351351

352-
MCSectionELF *getELFSection(StringRef Section, unsigned Type,
352+
MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
353353
unsigned Flags, unsigned EntrySize,
354-
StringRef Group) {
354+
const Twine &Group) {
355355
return getELFSection(Section, Type, Flags, EntrySize, Group, nullptr);
356356
}
357357

358-
MCSectionELF *getELFSection(StringRef Section, unsigned Type,
358+
MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
359359
unsigned Flags, unsigned EntrySize,
360-
StringRef Group, const char *BeginSymName) {
360+
const Twine &Group, const char *BeginSymName) {
361361
return getELFSection(Section, Type, Flags, EntrySize, Group, ~0,
362362
BeginSymName);
363363
}
364364

365-
MCSectionELF *getELFSection(StringRef Section, unsigned Type,
365+
MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
366366
unsigned Flags, unsigned EntrySize,
367-
StringRef Group, unsigned UniqueID) {
367+
const Twine &Group, unsigned UniqueID) {
368368
return getELFSection(Section, Type, Flags, EntrySize, Group, UniqueID,
369369
nullptr);
370370
}
371371

372-
MCSectionELF *getELFSection(StringRef Section, unsigned Type,
372+
MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
373373
unsigned Flags, unsigned EntrySize,
374-
StringRef Group, unsigned UniqueID,
374+
const Twine &Group, unsigned UniqueID,
375375
const char *BeginSymName);
376376

377-
MCSectionELF *getELFSection(StringRef Section, unsigned Type,
377+
MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
378378
unsigned Flags, unsigned EntrySize,
379379
const MCSymbolELF *Group, unsigned UniqueID,
380380
const char *BeginSymName,
381381
const MCSectionELF *Associated);
382382

383-
MCSectionELF *createELFRelSection(StringRef Name, unsigned Type,
383+
/// Get a section with the provided group identifier. This section is
384+
/// named by concatenating \p Prefix with '.' then \p Suffix. The \p Type
385+
/// describes the type of the section and \p Flags are used to further
386+
/// configure this named section.
387+
MCSectionELF *getELFNamedSection(const Twine &Prefix, const Twine &Suffix,
388+
unsigned Type, unsigned Flags,
389+
unsigned EntrySize = 0);
390+
391+
MCSectionELF *createELFRelSection(const Twine &Name, unsigned Type,
384392
unsigned Flags, unsigned EntrySize,
385393
const MCSymbolELF *Group,
386394
const MCSectionELF *Associated);

‎lib/CodeGen/TargetLoweringObjectFileImpl.cpp

Lines changed: 2 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -69,11 +69,9 @@ void TargetLoweringObjectFileELF::emitPersonalityValue(
6969
cast<MCSymbolELF>(getContext().getOrCreateSymbol(NameData));
7070
Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
7171
Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
72-
StringRef Prefix = ".data.";
73-
NameData.insert(NameData.begin(), Prefix.begin(), Prefix.end());
7472
unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
75-
MCSection *Sec = getContext().getELFSection(NameData, ELF::SHT_PROGBITS,
76-
Flags, 0, Label->getName());
73+
MCSection *Sec = getContext().getELFNamedSection(".data", Label->getName(),
74+
ELF::SHT_PROGBITS, Flags, 0);
7775
unsigned Size = DL.getPointerSize();
7876
Streamer.SwitchSection(Sec);
7977
Streamer.EmitValueToAlignment(DL.getPointerABIAlignment());

‎lib/MC/MCContext.cpp

Lines changed: 15 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -309,32 +309,40 @@ void MCContext::renameELFSection(MCSectionELF *Section, StringRef Name) {
309309
const_cast<MCSectionELF *>(Section)->setSectionName(CachedName);
310310
}
311311

312-
MCSectionELF *MCContext::createELFRelSection(StringRef Name, unsigned Type,
312+
MCSectionELF *MCContext::createELFRelSection(const Twine &Name, unsigned Type,
313313
unsigned Flags, unsigned EntrySize,
314314
const MCSymbolELF *Group,
315315
const MCSectionELF *Associated) {
316316
StringMap<bool>::iterator I;
317317
bool Inserted;
318-
std::tie(I, Inserted) = ELFRelSecNames.insert(std::make_pair(Name, true));
318+
std::tie(I, Inserted) =
319+
ELFRelSecNames.insert(std::make_pair(Name.str(), true));
319320

320321
return new (ELFAllocator.Allocate())
321322
MCSectionELF(I->getKey(), Type, Flags, SectionKind::getReadOnly(),
322323
EntrySize, Group, true, nullptr, Associated);
323324
}
324325

325-
MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
326+
MCSectionELF *MCContext::getELFNamedSection(const Twine &Prefix,
327+
const Twine &Suffix, unsigned Type,
328+
unsigned Flags,
329+
unsigned EntrySize) {
330+
return getELFSection(Prefix + "." + Suffix, Type, Flags, EntrySize, Suffix);
331+
}
332+
333+
MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
326334
unsigned Flags, unsigned EntrySize,
327-
StringRef Group, unsigned UniqueID,
335+
const Twine &Group, unsigned UniqueID,
328336
const char *BeginSymName) {
329337
MCSymbolELF *GroupSym = nullptr;
330-
if (!Group.empty())
338+
if (!Group.isTriviallyEmpty() && !Group.str().empty())
331339
GroupSym = cast<MCSymbolELF>(getOrCreateSymbol(Group));
332340

333341
return getELFSection(Section, Type, Flags, EntrySize, GroupSym, UniqueID,
334342
BeginSymName, nullptr);
335343
}
336344

337-
MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
345+
MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
338346
unsigned Flags, unsigned EntrySize,
339347
const MCSymbolELF *GroupSym,
340348
unsigned UniqueID,
@@ -345,7 +353,7 @@ MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
345353
Group = GroupSym->getName();
346354
// Do the lookup, if we have a hit, return it.
347355
auto IterBool = ELFUniquingMap.insert(
348-
std::make_pair(ELFSectionKey{Section, Group, UniqueID}, nullptr));
356+
std::make_pair(ELFSectionKey{Section.str(), Group, UniqueID}, nullptr));
349357
auto &Entry = *IterBool.first;
350358
if (!IterBool.second)
351359
return Entry.second;

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