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Store the sh_link of ARM_EXIDX directly in MCSectionELF. 

This avoids some pretty horrible and broken name based section handling.

llvm-svn: 234142
This commit is contained in:
Rafael Espindola 2015-04-06 04:25:18 +00:00
parent 176efac95b
commit 61e8ce36be
5 changed files with 120 additions and 25 deletions
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6
llvm/include/llvm/MC/MCContext.h
View File

@ -334,6 +334,12 @@ namespace llvm {
StringRef Group, unsigned UniqueID,
const char *BeginSymName);
const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
unsigned Flags, unsigned EntrySize,
const MCSymbol *Group, unsigned UniqueID,
const char *BeginSymName,
const MCSectionELF *Associated);
const MCSectionELF *createELFRelSection(StringRef Name, unsigned Type,
unsigned Flags, unsigned EntrySize,
const MCSymbol *Group,

15
llvm/lib/MC/ELFObjectWriter.cpp
View File

@ -1546,19 +1546,8 @@ void ELFObjectWriter::writeSection(MCAssembler &Asm,
}
if (TargetObjectWriter->getEMachine() == ELF::EM_ARM &&
Section.getType() == ELF::SHT_ARM_EXIDX) {
StringRef SecName(Section.getSectionName());
if (SecName == ".ARM.exidx") {
sh_link = SectionIndexMap.lookup(Asm.getContext().getELFSection(
".text", ELF::SHT_PROGBITS, ELF::SHF_EXECINSTR | ELF::SHF_ALLOC));
} else if (SecName.startswith(".ARM.exidx")) {
StringRef GroupName =
Section.getGroup() ? Section.getGroup()->getName() : "";
sh_link = SectionIndexMap.lookup(Asm.getContext().getELFSection(
SecName.substr(sizeof(".ARM.exidx") - 1), ELF::SHT_PROGBITS,
ELF::SHF_EXECINSTR | ELF::SHF_ALLOC, 0, GroupName));
}
}
Section.getType() == ELF::SHT_ARM_EXIDX)
sh_link = SectionIndexMap.lookup(Section.getAssociatedSection());
WriteSecHdrEntry(ShStrTabBuilder.getOffset(Section.getSectionName()),
Section.getType(),

19
llvm/lib/MC/MCContext.cpp
View File

@ -295,11 +295,22 @@ const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
StringRef Group, unsigned UniqueID,
const char *BeginSymName) {
MCSymbol *GroupSym = nullptr;
if (!Group.empty()) {
if (!Group.empty())
GroupSym = GetOrCreateSymbol(Group);
Group = GroupSym->getName();
}
return getELFSection(Section, Type, Flags, EntrySize, GroupSym, UniqueID,
BeginSymName, nullptr);
}
const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
unsigned Flags, unsigned EntrySize,
const MCSymbol *GroupSym,
unsigned UniqueID,
const char *BeginSymName,
const MCSectionELF *Associated) {
StringRef Group = "";
if (GroupSym)
Group = GroupSym->getName();
// Do the lookup, if we have a hit, return it.
auto IterBool = ELFUniquingMap.insert(
std::make_pair(ELFSectionKey{Section, Group, UniqueID}, nullptr));
@ -321,7 +332,7 @@ const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
MCSectionELF *Result =
new (*this) MCSectionELF(CachedName, Type, Flags, Kind, EntrySize,
GroupSym, UniqueID, Begin, nullptr);
GroupSym, UniqueID, Begin, Associated);
Entry.second = Result;
return Result;
}

15
llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
View File

@ -1083,14 +1083,13 @@ inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
}
// Get .ARM.extab or .ARM.exidx section
const MCSectionELF *EHSection = nullptr;
if (const MCSymbol *Group = FnSection.getGroup()) {
EHSection =
getContext().getELFSection(EHSecName, Type, Flags | ELF::SHF_GROUP,
FnSection.getEntrySize(), Group->getName());
} else {
EHSection = getContext().getELFSection(EHSecName, Type, Flags);
}
const MCSymbol *Group = FnSection.getGroup();
if (Group)
Flags |= ELF::SHF_GROUP;
const MCSectionELF *EHSection =
getContext().getELFSection(EHSecName, Type, Flags, 0, Group,
FnSection.getUniqueID(), nullptr, &FnSection);
assert(EHSection && "Failed to get the required EH section");
// Switch to .ARM.extab or .ARM.exidx section

90
llvm/test/MC/ARM/eh-link.s Normal file
View File

@ -0,0 +1,90 @@
@ RUN: llvm-mc %s -triple=armv7-unknown-linux-gnueabi -filetype=obj -o - \
@ RUN: | llvm-readobj -s | FileCheck %s
@ Test that the ARM_EXIDX sections point (Link) to the corresponding text
@ sections.
@ FIXME: The section numbers are not important. If llvm-readobj printed the
@ name first we could use a FileCheck variable.
@ CHECK: Section {
@ CHECK: Index: 6
@ CHECK-NEXT: Name: .text
@ CHECK-NEXT: Type: SHT_PROGBITS
@ CHECK-NEXT: Flags [
@ CHECK-NEXT: SHF_ALLOC
@ CHECK-NEXT: SHF_EXECINSTR
@ CHECK-NEXT: SHF_GROUP
@ CHECK-NEXT: ]
@ CHECK-NEXT: Address: 0x0
@ CHECK-NEXT: Offset: 0x54
@ CHECK-NEXT: Size: 4
@ CHECK-NEXT: Link: 0
@ CHECK-NEXT: Info: 0
@ CHECK-NEXT: AddressAlignment: 1
@ CHECK-NEXT: EntrySize: 0
@ CHECK-NEXT: }
@ CHECK-NEXT: Section {
@ CHECK-NEXT: Index: 7
@ CHECK-NEXT: Name: .ARM.exidx
@ CHECK-NEXT: Type: SHT_ARM_EXIDX
@ CHECK-NEXT: Flags [
@ CHECK-NEXT: SHF_ALLOC
@ CHECK-NEXT: SHF_GROUP
@ CHECK-NEXT: SHF_LINK_ORDER
@ CHECK-NEXT: ]
@ CHECK-NEXT: Address: 0x0
@ CHECK-NEXT: Offset: 0x58
@ CHECK-NEXT: Size: 8
@ CHECK-NEXT: Link: 6
@ CHECK-NEXT: Info: 0
@ CHECK-NEXT: AddressAlignment: 4
@ CHECK-NEXT: EntrySize: 0
@ CHECK-NEXT: }
@ CHECK: Section {
@ CHECK: Index: 9
@ CHECK-NEXT: Name: .text
@ CHECK-NEXT: Type: SHT_PROGBITS
@ CHECK-NEXT: Flags [
@ CHECK-NEXT: SHF_ALLOC
@ CHECK-NEXT: SHF_EXECINSTR
@ CHECK-NEXT: SHF_GROUP
@ CHECK-NEXT: ]
@ CHECK-NEXT: Address: 0x0
@ CHECK-NEXT: Offset: 0x60
@ CHECK-NEXT: Size: 4
@ CHECK-NEXT: Link: 0
@ CHECK-NEXT: Info: 0
@ CHECK-NEXT: AddressAlignment: 1
@ CHECK-NEXT: EntrySize: 0
@ CHECK-NEXT: }
@ CHECK-NEXT: Section {
@ CHECK-NEXT: Index: 10
@ CHECK-NEXT: Name: .ARM.exidx
@ CHECK-NEXT: Type: SHT_ARM_EXIDX
@ CHECK-NEXT: Flags [
@ CHECK-NEXT: SHF_ALLOC
@ CHECK-NEXT: SHF_GROUP
@ CHECK-NEXT: SHF_LINK_ORDER
@ CHECK-NEXT: ]
@ CHECK-NEXT: Address: 0x0
@ CHECK-NEXT: Offset: 0x64
@ CHECK-NEXT: Size: 8
@ CHECK-NEXT: Link: 9
@ CHECK-NEXT: Info: 0
@ CHECK-NEXT: AddressAlignment: 4
@ CHECK-NEXT: EntrySize: 0
@ CHECK-NEXT: }
.section .text,"axG",%progbits,f,comdat
f:
.fnstart
mov pc, lr
.fnend
.section .text,"axG",%progbits,g,comdat
g:
.fnstart
mov pc, lr
.fnend