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D56437.diff
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Mon, Jul 22, 1:17 PM

D56437.diff

Index: lld/trunk/ELF/InputFiles.cpp
===================================================================
--- lld/trunk/ELF/InputFiles.cpp
+++ lld/trunk/ELF/InputFiles.cpp
@@ -319,17 +319,6 @@
return Signature;
}
-template <class ELFT>
-ArrayRef<typename ObjFile<ELFT>::Elf_Word>
-ObjFile<ELFT>::getShtGroupEntries(const Elf_Shdr &Sec) {
- const ELFFile<ELFT> &Obj = this->getObj();
- ArrayRef<Elf_Word> Entries =
- CHECK(Obj.template getSectionContentsAsArray<Elf_Word>(&Sec), this);
- if (Entries.empty() || Entries[0] != GRP_COMDAT)
- fatal(toString(this) + ": unsupported SHT_GROUP format");
- return Entries.slice(1);
-}
-
template <class ELFT> bool ObjFile<ELFT>::shouldMerge(const Elf_Shdr &Sec) {
// On a regular link we don't merge sections if -O0 (default is -O1). This
// sometimes makes the linker significantly faster, although the output will
@@ -439,26 +428,34 @@
case SHT_GROUP: {
// De-duplicate section groups by their signatures.
StringRef Signature = getShtGroupSignature(ObjSections, Sec);
- bool IsNew = ComdatGroups.insert(CachedHashStringRef(Signature)).second;
this->Sections[I] = &InputSection::Discarded;
- // We only support GRP_COMDAT type of group. Get the all entries of the
- // section here to let getShtGroupEntries to check the type early for us.
- ArrayRef<Elf_Word> Entries = getShtGroupEntries(Sec);
-
- // If it is a new section group, we want to keep group members.
- // Group leader sections, which contain indices of group members, are
- // discarded because they are useless beyond this point. The only
- // exception is the -r option because in order to produce re-linkable
- // object files, we want to pass through basically everything.
+
+ ArrayRef<Elf_Word> Entries =
+ CHECK(Obj.template getSectionContentsAsArray<Elf_Word>(&Sec), this);
+ if (Entries.empty())
+ fatal(toString(this) + ": empty SHT_GROUP");
+
+ // The first word of a SHT_GROUP section contains flags. Currently,
+ // the standard defines only "GRP_COMDAT" flag for the COMDAT group.
+ // An group with the empty flag doesn't define anything; such sections
+ // are just skipped.
+ if (Entries[0] == 0)
+ continue;
+
+ if (Entries[0] != GRP_COMDAT)
+ fatal(toString(this) + ": unsupported SHT_GROUP format");
+
+ bool IsNew = ComdatGroups.insert(CachedHashStringRef(Signature)).second;
if (IsNew) {
if (Config->Relocatable)
this->Sections[I] = createInputSection(Sec);
- continue;
+ continue;
}
+
// Otherwise, discard group members.
- for (uint32_t SecIndex : Entries) {
+ for (uint32_t SecIndex : Entries.slice(1)) {
if (SecIndex >= Size)
fatal(toString(this) +
": invalid section index in group: " + Twine(SecIndex));
Index: lld/trunk/test/ELF/sht-group-empty.test
===================================================================
--- lld/trunk/test/ELF/sht-group-empty.test
+++ lld/trunk/test/ELF/sht-group-empty.test
@@ -0,0 +1,55 @@
+# RUN: yaml2obj %s -o %t.o
+# RUN: ld.lld %t.o %t.o -o %t -r
+# RUN: llvm-readobj -s %t | FileCheck %s
+
+# CHECK: Name: .text.foo
+# CHECK: Name: .rela.text.foo
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_X86_64
+Sections:
+ - Name: .group
+ Type: SHT_GROUP
+ Link: .symtab
+ Info: foo
+ Members:
+ - SectionOrType: GRP_COMDAT
+ - SectionOrType: .text.foo
+ - SectionOrType: .text.bar
+ - SectionOrType: .note
+ - Name: .note
+ Type: SHT_NOTE
+ Flags: [ SHF_GROUP ]
+ - Name: .text.foo
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]
+ - Name: .text.bar
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]
+ - Name: .rela.text.foo
+ Type: SHT_RELA
+ Flags: [ SHF_INFO_LINK, SHF_GROUP ]
+ Link: .symtab
+ Info: .text.foo
+ Relocations:
+ - Offset: 0x0000000000000000
+ Symbol: foo
+ Type: R_X86_64_64
+ - Name: .rela.text.bar
+ Type: SHT_RELA
+ Flags: [ SHF_INFO_LINK, SHF_GROUP ]
+ Link: .symtab
+ Info: .text.bar
+ Relocations:
+ - Offset: 0x0000000000000000
+ Symbol: bar
+ Type: R_X86_64_64
+Symbols:
+ Global:
+ - Name: foo
+ - Name: bar
+

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