diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp --- a/lld/ELF/Writer.cpp +++ b/lld/ELF/Writer.cpp @@ -2547,11 +2547,24 @@ } template void Writer::assignFileOffsetsBinary() { - uint64_t off = 0; + // Compute the minimum LMA of all non-empty non-NOBITS sections as minAddr. + auto needsOffset = [](OutputSection &sec) { + return sec.type != SHT_NOBITS && (sec.flags & SHF_ALLOC) && sec.size > 0; + }; + uint64_t minAddr = UINT64_MAX; for (OutputSection *sec : outputSections) - if (sec->flags & SHF_ALLOC) - off = setFileOffset(sec, off); - fileSize = alignTo(off, config->wordsize); + if (needsOffset(*sec)) { + sec->offset = sec->getLMA(); + minAddr = std::min(minAddr, sec->offset); + } + + // Sections are laid out at LMA minus minAddr. + fileSize = 0; + for (OutputSection *sec : outputSections) + if (needsOffset(*sec)) { + sec->offset -= minAddr; + fileSize = std::max(fileSize, sec->offset + sec->size); + } } static std::string rangeToString(uint64_t addr, uint64_t len) { diff --git a/lld/test/ELF/oformat-binary-ttext.s b/lld/test/ELF/oformat-binary-ttext.s --- a/lld/test/ELF/oformat-binary-ttext.s +++ b/lld/test/ELF/oformat-binary-ttext.s @@ -4,9 +4,8 @@ # RUN: ld.lld -N -Ttext 0x100 -o %t.out %t --oformat binary # RUN: od -t x1 -v %t.out | FileCheck %s --check-prefix=BIN -# BIN: 0000000 90 00 00 00 00 00 00 00 -# BIN-NEXT: 0000010 -# BIN-NOT: 0000020 +# BIN: 0000000 90 +# BIN-NEXT: 0000001 ## The same but without OMAGIC. # RUN: ld.lld -Ttext 0x100 -o %t.out %t --oformat binary diff --git a/lld/test/ELF/oformat-binary.s b/lld/test/ELF/oformat-binary.s --- a/lld/test/ELF/oformat-binary.s +++ b/lld/test/ELF/oformat-binary.s @@ -3,8 +3,8 @@ # RUN: ld.lld -o %t.out %t --oformat binary # RUN: od -t x1 -v %t.out | FileCheck %s -# CHECK: 000000 90 11 22 00 00 00 00 00 -# CHECK-NOT: 00000010 +# CHECK: 0000000 90 11 22 +# CHECK-NEXT: 0000003 ## Check case when linkerscript is used. # RUN: echo "SECTIONS { . = 0x1000; }" > %t.script @@ -15,6 +15,31 @@ # RUN: ld.lld -o %t2.out --script %t.script %t --oformat binary # RUN: od -t x1 -v %t2.out | FileCheck %s +## LMA(.text)=0x100, LMA(.mysec)=0x108. The minimum LMA of all non-empty sections is 0x100. +## We place an output section at its LMA minus 0x100. +# RUN: echo 'SECTIONS { .text 0x100 : {*(.text)} .mysec ALIGN(8) : {*(.mysec*)} }' > %talign.lds +# RUN: ld.lld -T %talign.lds %t --oformat binary -o %talign +# RUN: od -Ax -t x1 %talign | FileCheck %s --check-prefix=ALIGN --ignore-case + +# ALIGN: 000000 90 00 00 00 00 00 00 00 11 22 +# ALIGN-NEXT: 00000a + +## The empty section .data is ignored when computing the file size. +# RUN: echo 'SECTIONS { .text : {*(.text .mysec*)} .data 0x100 : {keep = .;}}' > %tempty.lds +# RUN: ld.lld -T %tempty.lds %t --oformat binary -o %tempty +# RUN: od -t x1 %tempty | FileCheck %s + +## NOBITS sections are ignored as well. +# RUN: echo 'SECTIONS { .text : {*(.text .mysec*)} .data 0x100 (NOLOAD) : {BYTE(0)}}' > %tnobits.lds +# RUN: ld.lld -T %tnobits.lds %t --oformat binary -o %tnobits +# RUN: od -t x1 %tnobits | FileCheck %s + +## FIXME .mysec should be placed at file offset 1. +## This does not work because for a section without PT_LOAD, we consider LMA = VMA. +# RUN: echo 'SECTIONS { .text : {*(.text)} .mysec 0x8 : AT(1) {*(.mysec*)} }' > %tlma.lds +# RUN: ld.lld -T %tlma.lds %t --oformat binary -o %tlma +# RUN: od -Ax -t x1 %tlma | FileCheck %s --check-prefix=ALIGN --ignore-case + # RUN: not ld.lld -o /dev/null %t --oformat foo 2>&1 \ # RUN: | FileCheck %s --check-prefix ERR # ERR: unknown --oformat value: foo