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 @@ -48,7 +48,7 @@ # 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 computed LMA of .data is 0x4000. The minimum LMA of all non-empty 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 @@ -93,7 +93,7 @@ # 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 minimum LMA of all non-empty 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 @@ -129,3 +129,78 @@ VAddr: 0x3000 Sections: - Section: .data + +## The first section (.text) is empty. Test that we skip its LMA until the first +## non-empty section, otherwise we would leave a large number of leading zeroes. +# RUN: yaml2obj --docnum=4 %s -o %t4 +# RUN: llvm-objcopy -O binary %t4 %t4.out +# RUN: od -A x -t x2 %t4.out | FileCheck %s --check-prefix=SKIP-EMPTY +# SKIP-EMPTY: 000000 3232 +# SKIP-EMPTY-NEXT: 000002 + +--- !ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_EXEC + Machine: EM_X86_64 +Sections: + - Name: .text + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_EXECINSTR ] + Address: 0x1000 + AddressAlign: 0x1000 + - Name: gap + Type: Fill + Size: 0x1000 + - Name: .data + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_WRITE ] + Content: "3232" +ProgramHeaders: + - Type: PT_LOAD + Flags: [ PF_R, PF_X ] + VAddr: 0x1000 + Sections: + - Section: .text + - Type: PT_LOAD + Flags: [ PF_R, PF_W ] + VAddr: 0x2000 + Sections: + - Section: .data + +## The last section (.data) is empty. Test that we stop dumping after the last +## non-empty section, otherwise we would leave a large number of trailing zeroes. +# RUN: yaml2obj --docnum=5 %s -o %t5 +# RUN: llvm-objcopy -O binary %t5 %t5.out +# RUN: od -A x -t x2 %t5.out | FileCheck %s --check-prefix=SKIP-EMPTY +--- !ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_EXEC + Machine: EM_X86_64 +Sections: + - Name: .text + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_EXECINSTR ] + Address: 0x1000 + AddressAlign: 0x1000 + Content: "3232" + - Name: gap + Type: Fill + Size: 0xffd + - Name: .data + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_WRITE ] +ProgramHeaders: + - Type: PT_LOAD + Flags: [ PF_R, PF_X ] + VAddr: 0x1000 + Sections: + - Section: .text + - Type: PT_LOAD + Flags: [ PF_R, PF_W ] + VAddr: 0x2000 + 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 @@ -2217,25 +2217,26 @@ Error BinaryWriter::finalize() { // 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. + // p_offset and p_paddr. Also compute the minimum LMA of all non-empty + // 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); + if (Sec.Size > 0) + MinAddr = std::min(MinAddr, Sec.Addr); } // 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. + // its last non-empty section, to match GNU objcopy's behaviour. TotalSize = 0; for (SectionBase &Sec : Obj.allocSections()) { Sec.Offset = Sec.Addr - MinAddr; - if (Sec.Type != SHT_NOBITS) + if (Sec.Type != SHT_NOBITS && Sec.Size > 0) TotalSize = std::max(TotalSize, Sec.Offset + Sec.Size); }