if (Config->Optimize == 0)
return false;
+ // Do not merge sections if generating a relocatable object. It makes
+ // the code simpler because we do not need to update relocation addends
+ // to reflect changes introduced by merging. Instead of that we write
+ // such "merge" sections into separate OutputSections and keep SHF_MERGE
+ // / SHF_STRINGS flags and sh_entsize value to be able to perform merging
+ // later during a final linking.
+ if (Config->Relocatable)
+ return false;
+
// A mergeable section with size 0 is useless because they don't have
// any data to merge. A mergeable string section with size 0 can be
// argued as invalid because it doesn't end with a null character.
Sections.push_back(S);
S->OutSec = this;
this->updateAlignment(S->Alignment);
+ // Keep sh_entsize value of the input section to be able to perform merging
+ // later during a final linking using the generated relocatable object.
+ if (Config->Relocatable && (S->getSectionHdr()->sh_flags & SHF_MERGE))
+ this->Header.sh_entsize = S->getSectionHdr()->sh_entsize;
}
// This function is called after we sort input sections
// For SHF_MERGE we create different output sections for each alignment.
// This makes each output section simple and keeps a single level mapping from
// input to output.
+ // In case of relocatable object generation we do not try to perform merging
+ // and treat SHF_MERGE sections as regular ones, but also create different
+ // output sections for them to allow merging at final linking stage.
uintX_t Alignment = 0;
- if (isa<MergeInputSection<ELFT>>(C))
+ if (isa<MergeInputSection<ELFT>>(C) ||
+ (Config->Relocatable && (H->sh_flags & SHF_MERGE)))
Alignment = std::max(H->sh_addralign, H->sh_entsize);
uint32_t Type = H->sh_type;
--- /dev/null
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: ld.lld %t.o -r -o %t-rel
+# RUN: llvm-readobj -s -section-data %t-rel | FileCheck %s
+
+# When linker generates a relocatable object it should keep "merge"
+# sections as-is: do not merge content, do not join regular and
+# "merge" sections, do not joint "merge" sections with different
+# entry size.
+
+# CHECK: Section {
+# CHECK: Index:
+# CHECK: Name: .data
+# CHECK-NEXT: Type: SHT_PROGBITS
+# CHECK-NEXT: Flags [
+# CHECK-NEXT: SHF_ALLOC
+# CHECK-NEXT: SHF_MERGE
+# CHECK-NEXT: ]
+# CHECK-NEXT: Address:
+# CHECK-NEXT: Offset:
+# CHECK-NEXT: Size: 12
+# CHECK-NEXT: Link: 0
+# CHECK-NEXT: Info: 0
+# CHECK-NEXT: AddressAlignment: 4
+# CHECK-NEXT: EntrySize: 4
+# CHECK-NEXT: SectionData (
+# CHECK-NEXT: 0000: 42000000 42000000 42000000
+# CHECK-NEXT: )
+# CHECK-NEXT: }
+# CHECK: Section {
+# CHECK: Index:
+# CHECK: Name: .data
+# CHECK-NEXT: Type: SHT_PROGBITS
+# CHECK-NEXT: Flags [
+# CHECK-NEXT: SHF_ALLOC
+# CHECK-NEXT: SHF_MERGE
+# CHECK-NEXT: ]
+# CHECK-NEXT: Address:
+# CHECK-NEXT: Offset:
+# CHECK-NEXT: Size: 16
+# CHECK-NEXT: Link: 0
+# CHECK-NEXT: Info: 0
+# CHECK-NEXT: AddressAlignment: 8
+# CHECK-NEXT: EntrySize: 8
+# CHECK-NEXT: SectionData (
+# CHECK-NEXT: 0000: 42000000 42000000 42000000 42000000
+# CHECK-NEXT: )
+# CHECK-NEXT: }
+# CHECK: Section {
+# CHECK: Index:
+# CHECK: Name: .data
+# CHECK-NEXT: Type: SHT_PROGBITS
+# CHECK-NEXT: Flags [
+# CHECK-NEXT: SHF_ALLOC
+# CHECK-NEXT: SHF_WRITE
+# CHECK-NEXT: ]
+# CHECK-NEXT: Address:
+# CHECK-NEXT: Offset:
+# CHECK-NEXT: Size: 16
+# CHECK-NEXT: Link: 0
+# CHECK-NEXT: Info: 0
+# CHECK-NEXT: AddressAlignment: 1
+# CHECK-NEXT: EntrySize: 0
+# CHECK-NEXT: SectionData (
+# CHECK-NEXT: 0000: 42000000 42000000 42000000 42000000
+# CHECK-NEXT: )
+# CHECK-NEXT: }
+
+ .section .data.1,"aM",@progbits,4
+ .align 4
+ .global foo
+foo:
+ .long 0x42
+ .long 0x42
+ .long 0x42
+
+ .section .data.2,"aM",@progbits,8
+ .align 8
+ .global bar
+bar:
+ .long 0x42
+ .long 0x42
+ .long 0x42
+ .long 0x42
+
+ .data
+ .global gar
+zed:
+ .long 0x42
+ .long 0x42
+ .long 0x42
+ .long 0x42