[llvm-objdump] Add Version Definitions dumper

Summary: `llvm-objdump` needs a `Version Definitions` dumper.

Reviewers: grimar, jhenderson

Reviewed By: grimar, jhenderson

Subscribers: rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58615

llvm-svn: 354871

Author: higuoxing

llvm/test/tools/llvm-objdump/verdef-elf.test

@@ -0,0 +1,41 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-objdump -p %t | FileCheck --strict-whitespace %s
+
+# CHECK:      Version definitions:
+# CHECK-NEXT: 1 0x01 0x075bcd15 foo
+# CHECK-NEXT: 2 0x02 0x3ade68b1 VERSION_1
+# CHECK-NEXT: 	                VERSION_2 
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+  Entry:           0x0000000000001000
+Sections:
+  - Name:            .gnu.version_d
+    Type:            SHT_GNU_verdef
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000000000000230
+    Link:            .dynstr
+    AddressAlign:    0x0000000000000004
+    Info:            0x0000000000000003
+    Entries:
+      - Version:         1
+        Flags:           1
+        VersionNdx:      1
+        Hash:            123456789
+        Names:
+          - foo
+      - Version:         1
+        Flags:           2
+        VersionNdx:      2
+        Hash:            987654321
+        Names:
+          - VERSION_1
+          - VERSION_2
+DynamicSymbols:
+  Global:
+    - Name:            bar
+...

llvm/tools/llvm-objdump/ELFDump.cpp

@@ -297,6 +297,43 @@ void printSymbolVersionDependency(ArrayRef<uint8_t> Contents,
   }
 }
 
+template <class ELFT>
+void printSymbolVersionDefinition(const typename ELFT::Shdr &Shdr,
+                                  ArrayRef<uint8_t> Contents,
+                                  StringRef StrTab) {
+  typedef ELFFile<ELFT> ELFO;
+  typedef typename ELFO::Elf_Verdef Elf_Verdef;
+  typedef typename ELFO::Elf_Verdaux Elf_Verdaux;
+
+  outs() << "Version definitions:\n";
+
+  const uint8_t *Buf = Contents.data();
+  uint32_t VerdefIndex = 1;
+  // sh_info contains the number of entries in the SHT_GNU_verdef section. To
+  // make the index column have consistent width, we should insert blank spaces
+  // according to sh_info.
+  uint16_t VerdefIndexWidth = std::to_string(Shdr.sh_info).size();
+  while (Buf) {
+    const Elf_Verdef *Verdef = reinterpret_cast<const Elf_Verdef *>(Buf);
+    outs() << format_decimal(VerdefIndex++, VerdefIndexWidth) << " "
+           << format("0x%02" PRIx16 " ", (uint16_t)Verdef->vd_flags)
+           << format("0x%08" PRIx32 " ", (uint32_t)Verdef->vd_hash);
+
+    const uint8_t *BufAux = Buf + Verdef->vd_aux;
+    uint16_t VerdauxIndex = 0;
+    while (BufAux) {
+      const Elf_Verdaux *Verdaux =
+          reinterpret_cast<const Elf_Verdaux *>(BufAux);
+      if (VerdauxIndex)
+        outs() << std::string(VerdefIndexWidth + 17, ' ');
+      outs() << StringRef(StrTab.drop_front(Verdaux->vda_name).data()) << '\n';
+      BufAux = Verdaux->vda_next ? BufAux + Verdaux->vda_next : nullptr;
+      ++VerdauxIndex;
+    }
+    Buf = Verdef->vd_next ? Buf + Verdef->vd_next : nullptr;
+  }
+}
+
 template <class ELFT>
 void printSymbolVersionInfo(const ELFFile<ELFT> *Elf, StringRef FileName) {
   typedef typename ELFT::Shdr Elf_Shdr;
@@ -306,7 +343,8 @@ void printSymbolVersionInfo(const ELFFile<ELFT> *Elf, StringRef FileName) {
     report_error(FileName, SectionsOrError.takeError());
 
   for (const Elf_Shdr &Shdr : *SectionsOrError) {
-    if (Shdr.sh_type != ELF::SHT_GNU_verneed)
+    if (Shdr.sh_type != ELF::SHT_GNU_verneed &&
+        Shdr.sh_type != ELF::SHT_GNU_verdef)
       continue;
 
     auto ContentsOrError = Elf->getSectionContents(&Shdr);
@@ -321,8 +359,11 @@ void printSymbolVersionInfo(const ELFFile<ELFT> *Elf, StringRef FileName) {
     if (!StrTabOrError)
       report_error(FileName, StrTabOrError.takeError());
 
-    printSymbolVersionDependency<ELFT>(*ContentsOrError, *StrTabOrError);
-    // TODO: Implement symbol version definitions dumper.
+    if (Shdr.sh_type == ELF::SHT_GNU_verneed)
+      printSymbolVersionDependency<ELFT>(*ContentsOrError, *StrTabOrError);
+    else
+      printSymbolVersionDefinition<ELFT>(Shdr, *ContentsOrError,
+                                         *StrTabOrError);
   }
 }