diff --git a/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test b/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test --- a/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test +++ b/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test @@ -1,9 +1,21 @@ -# RUN: yaml2obj %s -o %t -# RUN: llvm-objcopy -O binary %t %t2 -# RUN: od -t x2 %t2 | FileCheck %s --ignore-case -# RUN: wc -c < %t2 | FileCheck %s --check-prefix=SIZE +## The computed LMA of a section in a PT_LOAD equals sh_offset-p_offset+p_paddr. +## The byte offset difference between two sections equals the difference between their LMAs. -!ELF +## Corollary: if two sections are in the same PT_LOAD, the byte offset +## difference equals the difference between their sh_addr fields. + +# RUN: yaml2obj --docnum=1 %s -o %t1 +# RUN: llvm-objcopy -O binary %t1 %t1.out +# RUN: od -A x -t x2 %t1.out | FileCheck %s --check-prefix=CHECK1 --ignore-case +# RUN: wc -c %t1.out | FileCheck %s --check-prefix=SIZE1 + +# CHECK1: 000000 c3c3 c3c3 0000 0000 0000 0000 0000 0000 +# CHECK1-NEXT: 000010 0000 0000 0000 0000 0000 0000 0000 0000 +# CHECK1-NEXT: * +# CHECK1-NEXT: 001000 3232 +# SIZE1: 4098 + +--- !ELF FileHeader: Class: ELFCLASS64 Data: ELFDATA2LSB @@ -14,32 +26,107 @@ Type: SHT_PROGBITS Flags: [ SHF_ALLOC, SHF_EXECINSTR ] Address: 0x1000 - AddressAlign: 0x0000000000001000 + AddressAlign: 0x1000 Content: "c3c3c3c3" - Name: .data Type: SHT_PROGBITS - Flags: [ SHF_ALLOC ] + Flags: [ SHF_ALLOC, SHF_WRITE ] Address: 0x2000 - AddressAlign: 0x0000000000001000 + AddressAlign: 0x1000 Content: "3232" ProgramHeaders: - Type: PT_LOAD - Flags: [ PF_X, PF_R ] - VAddr: 0x1000 - PAddr: 0x1000 - Align: 0x1000 + Flags: [ PF_R, PF_W ] Sections: - Section: .text + - Section: .data + +## The computed LMA of a section not in a PT_LOAD equals its sh_addr. + +# RUN: yaml2obj --docnum=2 %s -o %t2 +# RUN: llvm-objcopy -O binary %t2 %t2.out +# RUN: od -A x -t x2 %t2.out | FileCheck %s --check-prefix=CHECK2 --ignore-case +# RUN: wc -c %t2.out | FileCheck %s --check-prefix=SIZE2 + +## The computed LMA of .data is 0x4000. The minimum LMA of all sections is 0x1000. +## The content of .data will be written at 0x4000-0x1000 = 0x3000. +# CHECK2: 000000 c3c3 c3c3 0000 0000 0000 0000 0000 0000 +# CHECK2-NEXT: 000010 0000 0000 0000 0000 0000 0000 0000 0000 +# CHECK2-NEXT: * +# CHECK2-NEXT: 003000 3232 +# SIZE2: 12290 + +--- !ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_EXEC + Machine: EM_X86_64 +Sections: + - Name: .text + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_EXECINSTR ] + ## Not in a PT_LOAD. LMA = sh_addr = 0x1000. + Address: 0x1000 + AddressAlign: 0x1000 + Content: "c3c3c3c3" + - Name: .data + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_WRITE ] + ## LMA = sh_offset-p_offset+p_paddr = 0x2000-0x2000+0x4000 = 0x4000. + Address: 0x2000 + AddressAlign: 0x1000 + Content: "3232" +ProgramHeaders: - Type: PT_LOAD Flags: [ PF_R, PF_W ] VAddr: 0x2000 + ## p_vaddr is increased from 0x2000 to 0x4000. PAddr: 0x4000 - Align: 0x1000 Sections: - Section: .data -# CHECK: 0000000 c3c3 c3c3 0000 0000 0000 0000 0000 0000 -# CHECK-NEXT: 0000020 0000 0000 0000 0000 0000 0000 0000 0000 -# CHECK-NEXT: * -# CHECK-NEXT: 0030000 3232 -# SIZE: 12290 +## Check that we use sh_offset instead of sh_addr to decide where to write section contents. + +# RUN: yaml2obj --docnum=3 %s -o %t3 +# RUN: llvm-objcopy -O binary %t3 %t3.out +# RUN: od -A x -t x2 %t3.out | FileCheck %s --check-prefix=CHECK3 --ignore-case +# RUN: wc -c %t3.out | FileCheck %s --check-prefix=SIZE3 + +## The minimum LMA of all sections is 0x1000. +## The content of .data will be written at 0x3000-0x1000 = 0x2000. +# CHECK3: 000000 c3c3 c3c3 0000 0000 0000 0000 0000 0000 +# CHECK3-NEXT: 000010 0000 0000 0000 0000 0000 0000 0000 0000 +# CHECK3-NEXT: * +# CHECK3-NEXT: 002000 3232 +# SIZE3: 8194 + +--- !ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_EXEC + Machine: EM_X86_64 +Sections: + - Name: .text + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_EXECINSTR ] + ## Not in a PT_LOAD. LMA = sh_addr = 0x1000. + Address: 0x1000 + AddressAlign: 0x1000 + Content: "c3c3c3c3" + - Name: .data + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_WRITE ] + ## sh_addr is increased from 0x2000 to 0x3000, but it is ignored. + ## LMA = sh_offset-p_offset+p_paddr = 0x2000-0x2000+0x3000 = 0x3000. + Address: 0x3000 + AddressAlign: 0x1000 + Content: "3232" +ProgramHeaders: + - Type: PT_LOAD + Flags: [ PF_R, PF_W ] + VAddr: 0x3000 + PAddr: 0x3000 + Sections: + - Section: .data diff --git a/llvm/tools/llvm-objcopy/ELF/Object.cpp b/llvm/tools/llvm-objcopy/ELF/Object.cpp --- a/llvm/tools/llvm-objcopy/ELF/Object.cpp +++ b/llvm/tools/llvm-objcopy/ELF/Object.cpp @@ -2253,38 +2253,28 @@ std::unique(std::begin(OrderedSegments), std::end(OrderedSegments)); OrderedSegments.erase(End, std::end(OrderedSegments)); - uint64_t Offset = 0; - - // Modify the first segment so that there is no gap at the start. This allows - // our layout algorithm to proceed as expected while not writing out the gap - // at the start. - if (!OrderedSegments.empty()) { - Segment *Seg = OrderedSegments[0]; - const SectionBase *Sec = Seg->firstSection(); - auto Diff = Sec->OriginalOffset - Seg->OriginalOffset; - Seg->OriginalOffset += Diff; - // The size needs to be shrunk as well. - Seg->FileSize -= Diff; - // The PAddr needs to be increased to remove the gap before the first - // section. - Seg->PAddr += Diff; - uint64_t LowestPAddr = Seg->PAddr; - for (Segment *Segment : OrderedSegments) { - Segment->Offset = Segment->PAddr - LowestPAddr; - Offset = std::max(Offset, Segment->Offset + Segment->FileSize); - } + // Compute the section LMA based on its sh_offset and the containing segment's + // p_offset and p_paddr. Also compute the minimum LMA of all sections as + // MinAddr. In the output, the contents between address 0 and MinAddr will be + // skipped. + uint64_t MinAddr = UINT64_MAX; + for (SectionBase &Sec : Obj.allocSections()) { + if (Sec.ParentSegment != nullptr) + Sec.Addr = + Sec.Offset - Sec.ParentSegment->Offset + Sec.ParentSegment->PAddr; + MinAddr = std::min(MinAddr, Sec.Addr); } - layoutSections(Obj.allocSections(), Offset); - // Now that every section has been laid out we just need to compute the total // file size. This might not be the same as the offset returned by // layoutSections, because we want to truncate the last segment to the end of // its last section, to match GNU objcopy's behaviour. TotalSize = 0; - for (const SectionBase &Sec : Obj.allocSections()) + for (SectionBase &Sec : Obj.allocSections()) { + Sec.Offset = Sec.Addr - MinAddr; if (Sec.Type != SHT_NOBITS) TotalSize = std::max(TotalSize, Sec.Offset + Sec.Size); + } if (Error E = Buf.allocate(TotalSize)) return E;