Index: ELF/SyntheticSections.cpp =================================================================== --- ELF/SyntheticSections.cpp +++ ELF/SyntheticSections.cpp @@ -2919,6 +2919,7 @@ void MergeSyntheticSection::addSection(MergeInputSection *MS) { MS->Parent = this; Sections.push_back(MS); + Alignment = std::max(Alignment, MS->Alignment); } MergeTailSection::MergeTailSection(StringRef Name, uint32_t Type, @@ -3062,8 +3063,11 @@ // // Using Entsize in here also allows us to propagate it to the synthetic // section. + // + // SHF_STRINGS section with different alignments should not be merged. return Sec->Name == OutsecName && Sec->Flags == MS->Flags && - Sec->Entsize == MS->Entsize && Sec->Alignment == MS->Alignment; + Sec->Entsize == MS->Entsize && + (Sec->Alignment == MS->Alignment || !(Sec->Flags & SHF_STRINGS)); }); if (I == MergeSections.end()) { MergeSyntheticSection *Syn = Index: test/ELF/merge-align2.s =================================================================== --- /dev/null +++ test/ELF/merge-align2.s @@ -0,0 +1,35 @@ +# REQUIRES: x86 +# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o + +# RUN: ld.lld %t.o -o %t +# RUN: llvm-readelf -S %t | FileCheck --check-prefix=SEC %s +# RUN: llvm-readelf -x .cst8 %t | FileCheck %s + +# RUN: ld.lld -O0 -r %t.o -o %t1.o +# RUN: llvm-readelf -S %t1.o | FileCheck --check-prefix=SEC %s +# RUN: llvm-readelf -x .cst8 %t1.o | FileCheck %s + +## Check that if we have SHF_MERGE sections with the same name, flags and +## entsize, but different alignments, we combine them with the maximum input +## alignment as the output alignment. + +# SEC: Name Type {{.*}} Size ES Flg Lk Inf Al +# SEC: .cst8 PROGBITS {{.*}} 000018 08 AM 0 0 8 + +# CHECK: 0x{{[0-9a-f]+}} 02000000 00000000 01000000 00000000 +# CHECK-NEXT: 0x{{[0-9a-f]+}} 03000000 00000000 + +.section .cst8,"aM",@progbits,8,unique,0 +.align 4 +.quad 1 +.quad 1 + +.section .cst8,"aM",@progbits,8,unique,1 +.align 4 +.quad 1 +.quad 2 + +.section .cst8,"aM",@progbits,8,unique,2 +.align 8 +.quad 1 +.quad 3 Index: test/ELF/merge-entsize2.s =================================================================== --- /dev/null +++ test/ELF/merge-entsize2.s @@ -0,0 +1,49 @@ +# REQUIRES: x86 +# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o + +# RUN: ld.lld %t.o -o %t +# RUN: llvm-readelf -S %t | FileCheck --check-prefix=SEC %s +# RUN: llvm-readelf -x .cst %t | FileCheck --check-prefix=HEX %s + +# RUN: ld.lld -O0 -r %t.o -o %t1.o +# RUN: llvm-readelf -S %t1.o | FileCheck --check-prefix=SEC-R %s +# RUN: llvm-readelf -x .cst %t1.o | FileCheck --check-prefix=HEX-R %s + +## Check that SHF_MERGE sections with the same name, sh_flags and sh_entsize +## are grouped together and can be merged within the group. + +## .cst 0 and .cst 1 are merged (sh_entsize=4). The result and .cst 2 and +## combined (sh_entsize=8). The output sh_entsize is 0. +# SEC: Name Type {{.*}} Size ES Flg Lk Inf Al +# SEC: .cst PROGBITS {{.*}} 000020 00 AM 0 0 8 + +## .cst 0 and .cst 1 are merged, but emitted as a separate output section. +# SEC-R: .cst PROGBITS {{.*}} 00000c 04 AM 0 0 4 +# SEC-R: .cst PROGBITS {{.*}} 000010 08 AM 0 0 8 + +# HEX: Hex dump of section '.cst': +# HEX-NEXT: 0x{{[0-9a-f]+}} 01000000 00000000 02000000 00000000 +# HEX-NEXT: 0x{{[0-9a-f]+}} 01000000 00000000 03000000 00000000 + +# HEX-R: Hex dump of section '.cst': +# HEX-R-NEXT: 0x00000000 01000000 00000000 02000000 +# HEX-R-EMPTY: +# HEX-R-NEXT: Hex dump of section '.cst': +# HEX-R-NEXT: 0x00000000 01000000 00000000 03000000 00000000 + +.section .cst,"aM",@progbits,4,unique,0 +.align 2 +.long 1 +.long 0 +.long 2 + +.section .cst,"aM",@progbits,4,unique,1 +.align 4 +.long 1 +.long 0 +.long 2 + +.section .cst,"aM",@progbits,8,unique,2 +.align 8 +.quad 1 +.quad 3 Index: test/ELF/merge-reloc-O0.s =================================================================== --- test/ELF/merge-reloc-O0.s +++ /dev/null @@ -1,48 +0,0 @@ -# REQUIRES: x86 -# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o -# RUN: ld.lld %t.o -r -o %t2.o -O0 -# RUN: llvm-readobj -S --section-data %t2.o | FileCheck %s - -# We combine just the sections with the same name and sh_entsize. - -# CHECK: Name: .foo -# 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: -# CHECK-NEXT: Info: -# CHECK-NEXT: AddressAlignment: 1 -# CHECK-NEXT: EntrySize: 8 -# CHECK-NEXT: SectionData ( -# CHECK-NEXT: 0000: 41000000 00000000 42000000 00000000 -# CHECK-NEXT: ) - -# CHECK: Name: .foo -# 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: 8 -# CHECK-NEXT: Link: -# CHECK-NEXT: Info: -# CHECK-NEXT: AddressAlignment: 1 -# CHECK-NEXT: EntrySize: 4 -# CHECK-NEXT: SectionData ( -# CHECK-NEXT: 0000: 41000000 42000000 -# CHECK-NEXT: ) - - .section .foo, "aM",@progbits,8,unique,0 - .quad 0x41 - .section .foo, "aM",@progbits,8,unique,1 - .quad 0x42 - .section .foo, "aM",@progbits,4,unique,2 - .long 0x41 - .long 0x42 Index: test/ELF/tail-merge-string-align2.s =================================================================== --- /dev/null +++ test/ELF/tail-merge-string-align2.s @@ -0,0 +1,23 @@ +# REQUIRES: x86 +# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o + +# RUN: ld.lld %t.o -o %t +# RUN: llvm-readelf -S %t | FileCheck --check-prefix=SEC %s +# RUN: llvm-readelf -x .rodata %t | FileCheck %s + +# SEC: Name Type {{.*}} Size ES Flg Lk Inf Al +# SEC: .rodata PROGBITS {{.*}} 000006 01 AMS 0 0 8 + +# CHECK: a.b.c. + +.section .rodata.str1.8,"aMS",@progbits,1 +.align 8 +.asciz "a" + +.section .rodata.str1.2,"aMS",@progbits,1 +.align 2 +.asciz "b" + +.section .rodata.str1.1,"aMS",@progbits,1 +.align 1 +.asciz "c"