[llvm-objcopy] Support the rest of the ELF formats

[jakehehrlich]

Summary

We haven't been supporting anything but ELF64LE since the start. Luckily this was always accounted for and the change is pretty trivial. B35281 requests this change for ELF32LE. This change adds support for ELF32LE, ELF64BE, and ELF32BE with all supported features that already existed for ELF64LE.

[davide]

tools/llvm-objcopy/llvm-objcopy.cpp

253

auto *

[jakehehrlich]

Replaced explicit types with auto as recommended. Thanks Davide!

[jhenderson]

LGTM.

I don't see any sensible way of doing this, but it would be really nice if every single one of our test cases could be run for all 4 forms, as I believe the same behaviour should be present in all of them. The test coverage for this change though is good enough though. Thanks.

test/tools/llvm-objcopy/elf32be.test

+# RUN: yaml2obj %s > %t
+# RUN: llvm-objcopy %t %t2
+# RUN: llvm-readobj -file-headers -sections %t2 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS32
+  Data:            ELFDATA2MSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .bss
+    Type:            SHT_NOBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000000010
+    Size:            64
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x0000000000000010
+    Content:         "00000000"
+
+# CHECK: Class: 32-bit
+# CHECK: DataEncoding: BigEndian
+
+# CHECK:      Name: .bss
+# CHECK:      Name: .text
+# CHECK:      Name: .shstrtab

test/tools/llvm-objcopy/elf32le.test

+# RUN: yaml2obj %s > %t
+# RUN: llvm-objcopy %t %t2
+# RUN: llvm-readobj -file-headers -sections %t2 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS32
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .bss
+    Type:            SHT_NOBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000000010
+    Size:            64
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x0000000000000010
+    Content:         "00000000"
+
+# CHECK: Class: 32-bit
+# CHECK: DataEncoding: LittleEndian
+
+# CHECK:      Name: .bss
+# CHECK:      Name: .text
+# CHECK:      Name: .shstrtab

test/tools/llvm-objcopy/elf64be.test

+# RUN: yaml2obj %s > %t
+# RUN: llvm-objcopy %t %t2
+# RUN: llvm-readobj -file-headers -sections %t2 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2MSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .bss
+    Type:            SHT_NOBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000000010
+    Size:            64
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x0000000000000010
+    Content:         "00000000"
+
+# CHECK: Class: 64-bit
+# CHECK: DataEncoding: BigEndian
+
+# CHECK:      Name: .bss
+# CHECK:      Name: .text
+# CHECK:      Name: .shstrtab

tools/llvm-objcopy/llvm-objcopy.cpp

void SplitDWOToFile(const ELFObjectFile<ELFT> &ObjFile, StringRef File) {
 
   DWOFile.removeSections([&](const SectionBase &Sec) {
     return OnlyKeepDWOPred<ELFT>(DWOFile, Sec);
   });
   DWOFile.finalize();
   WriteObjectFile(DWOFile, File);
 }
 
-void CopyBinary(const ELFObjectFile<ELF64LE> &ObjFile) {
-  std::unique_ptr<Object<ELF64LE>> Obj;
+template <class ELFT>
+void CopyBinary(const ELFObjectFile<ELFT> &ObjFile) {
+  std::unique_ptr<Object<ELFT>> Obj;
 
   if (!OutputFormat.empty() && OutputFormat != "binary")
     error("invalid output format '" + OutputFormat + "'");
   if (!OutputFormat.empty() && OutputFormat == "binary")
-    Obj = llvm::make_unique<BinaryObject<ELF64LE>>(ObjFile);
+    Obj = llvm::make_unique<BinaryObject<ELFT>>(ObjFile);
   else
-    Obj = llvm::make_unique<ELFObject<ELF64LE>>(ObjFile);
+    Obj = llvm::make_unique<ELFObject<ELFT>>(ObjFile);
 
   if (!SplitDWO.empty())
-    SplitDWOToFile<ELF64LE>(ObjFile, SplitDWO.getValue());
+    SplitDWOToFile<ELFT>(ObjFile, SplitDWO.getValue());
 
   SectionPred RemovePred = [](const SectionBase &) { return false; };
 
   if (!ToRemove.empty()) {
     RemovePred = [&](const SectionBase &Sec) {
       return std::find(std::begin(ToRemove), std::end(ToRemove), Sec.Name) !=
              std::end(ToRemove);
     };
int main(int argc, char **argv) {
   if (InputFilename.empty()) {
     cl::PrintHelpMessage();
     return 2;
   }
   Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(InputFilename);
   if (!BinaryOrErr)
     reportError(InputFilename, BinaryOrErr.takeError());
   Binary &Binary = *BinaryOrErr.get().getBinary();
-  if (ELFObjectFile<ELF64LE> *o = dyn_cast<ELFObjectFile<ELF64LE>>(&Binary)) {
+  if (auto *o = dyn_cast<ELFObjectFile<ELF64LE>>(&Binary)) {
+    CopyBinary(*o);
+    return 0;
+  }
+  if (auto *o = dyn_cast<ELFObjectFile<ELF32LE>>(&Binary)) {
+    CopyBinary(*o);
+    return 0;
+  }
+  if (auto *o = dyn_cast<ELFObjectFile<ELF64BE>>(&Binary)) {
+    CopyBinary(*o);
+    return 0;
+  }
+  if (auto *o = dyn_cast<ELFObjectFile<ELF32BE>>(&Binary)) {
     CopyBinary(*o);
     return 0;
   }
   reportError(InputFilename, object_error::invalid_file_type);
 }