[yaml2obj] - Add a support for changing EntSize.

I was trying to add a test case for LLD and found that it
is impossible to set sh_entsize via yaml.
The patch implements the missing part.

Differential revision: https://reviews.llvm.org/D50235

llvm-svn: 339113

llvm/include/llvm/ObjectYAML/ELFYAML.h

@@ -123,6 +123,7 @@ struct Section {
   StringRef Link;
   StringRef Info;
   llvm::yaml::Hex64 AddressAlign;
+  Optional<llvm::yaml::Hex64> EntSize;
 
   Section(SectionKind Kind) : Kind(Kind) {}
   virtual ~Section();

llvm/lib/ObjectYAML/ELFYAML.cpp

@@ -816,6 +816,7 @@ static void commonSectionMapping(IO &IO, ELFYAML::Section &Section) {
   IO.mapOptional("Address", Section.Address, Hex64(0));
   IO.mapOptional("Link", Section.Link, StringRef());
   IO.mapOptional("AddressAlign", Section.AddressAlign, Hex64(0));
+  IO.mapOptional("EntSize", Section.EntSize);
   IO.mapOptional("Info", Section.Info, StringRef());
 }
 

llvm/test/tools/yaml2obj/elf-ent-size.yaml

+# RUN: yaml2obj %s -o %t
+# RUN: llvm-readobj -sections %t | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  OSABI:           ELFOSABI_FREEBSD
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Type:            SHT_PROGBITS
+    Name:            .strings
+    Flags:           [ SHF_ALLOC, SHF_MERGE, SHF_STRINGS ]
+    AddressAlign:    0x04
+    Content:         "FFFFFFFFFFFFFFFF"
+    EntSize:         0x1
+  - Name:            .mydynamic
+    Type:            SHT_DYNAMIC
+    EntSize:         0x0
+
+
+## Check we were able to set entry size for .strings and .mydynamic
+# CHECK:       Name: .strings
+# CHECK-NEXT:   Type: SHT_PROGBITS
+# CHECK-NEXT:   Flags [
+# CHECK-NEXT:     SHF_ALLOC
+# CHECK-NEXT:     SHF_MERGE
+# CHECK-NEXT:     SHF_STRINGS
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Address:
+# CHECK-NEXT:   Offset:
+# CHECK-NEXT:   Size:
+# CHECK-NEXT:   Link:
+# CHECK-NEXT:   Info:
+# CHECK-NEXT:   AddressAlignment:
+# CHECK-NEXT:   EntrySize: 1
+# CHECK-NEXT: }
+# CHECK:        Name: .mydynamic
+# CHECK-NEXT:   Type: SHT_DYNAMIC
+# CHECK-NEXT:   Flags [
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Address:
+# CHECK-NEXT:   Offset:
+# CHECK-NEXT:   Size:
+# CHECK-NEXT:   Link:
+# CHECK-NEXT:   Info:
+# CHECK-NEXT:   AddressAlignment:
+# CHECK-NEXT:   EntrySize: 0
+# CHECK-NEXT: }

llvm/tools/yaml2obj/yaml2elf.cpp

@@ -461,7 +461,9 @@ ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
   Section.Content.writeAsBinary(OS);
   for (auto i = Section.Content.binary_size(); i < Section.Size; ++i)
     OS.write(0);
-  if (Section.Type == llvm::ELF::SHT_RELR)
+  if (Section.EntSize)
+    SHeader.sh_entsize = *Section.EntSize;
+  else if (Section.Type == llvm::ELF::SHT_RELR)
     SHeader.sh_entsize = sizeof(Elf_Relr);
   else if (Section.Type == llvm::ELF::SHT_DYNAMIC)
     SHeader.sh_entsize = sizeof(Elf_Dyn);