From badb15e1da683f56cf6db52541d44ec296633a33 Mon Sep 17 00:00:00 2001
From: Xing GUO <higuoxing@gmail.com>
Date: Sat, 2 Mar 2019 04:20:28 +0000
Subject: [PATCH] [llvm-objdump] Should print unknown d_tag in hex format

Summary:
Currently, `llvm-objdump` prints "unknown" instead of d_tag value in hex format. Because getDynamicTagAsString returns "unknown" rather than empty
string.

Reviewers: grimar, jhenderson

Reviewed By: jhenderson

Subscribers: rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58763

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355262 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Object/ELF.h                        |  4 ++--
 lib/Object/ELF.cpp                               |  6 +++---
 test/tools/llvm-objdump/elf-dynamic-section.test |  3 +++
 tools/llvm-objdump/ELFDump.cpp                   | 11 ++---------
 4 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/include/llvm/Object/ELF.h b/include/llvm/Object/ELF.h
index 1ba32b4875c..a49f7128c64 100644
--- a/include/llvm/Object/ELF.h
+++ b/include/llvm/Object/ELF.h
@@ -114,8 +114,8 @@ public:
                              SmallVectorImpl<char> &Result) const;
   uint32_t getRelativeRelocationType() const;
 
-  const char *getDynamicTagAsString(unsigned Arch, uint64_t Type) const;
-  const char *getDynamicTagAsString(uint64_t Type) const;
+  std::string getDynamicTagAsString(unsigned Arch, uint64_t Type) const;
+  std::string getDynamicTagAsString(uint64_t Type) const;
 
   /// Get the symbol for a given relocation.
   Expected<const Elf_Sym *> getRelocationSymbol(const Elf_Rel *Rel,
diff --git a/lib/Object/ELF.cpp b/lib/Object/ELF.cpp
index 314be34ef59..dd8f3a9f331 100644
--- a/lib/Object/ELF.cpp
+++ b/lib/Object/ELF.cpp
@@ -424,7 +424,7 @@ ELFFile<ELFT>::android_relas(const Elf_Shdr *Sec) const {
 }
 
 template <class ELFT>
-const char *ELFFile<ELFT>::getDynamicTagAsString(unsigned Arch,
+std::string ELFFile<ELFT>::getDynamicTagAsString(unsigned Arch,
                                                  uint64_t Type) const {
 #define DYNAMIC_STRINGIFY_ENUM(tag, value)                                     \
   case value:                                                                  \
@@ -470,12 +470,12 @@ const char *ELFFile<ELFT>::getDynamicTagAsString(unsigned Arch,
 #undef DYNAMIC_TAG_MARKER
 #undef DYNAMIC_STRINGIFY_ENUM
   default:
-    return "unknown";
+    return "<unknown:>0x" + utohexstr(Type, true);
   }
 }
 
 template <class ELFT>
-const char *ELFFile<ELFT>::getDynamicTagAsString(uint64_t Type) const {
+std::string ELFFile<ELFT>::getDynamicTagAsString(uint64_t Type) const {
   return getDynamicTagAsString(getHeader()->e_machine, Type);
 }
 
diff --git a/test/tools/llvm-objdump/elf-dynamic-section.test b/test/tools/llvm-objdump/elf-dynamic-section.test
index 0391ac719f3..b2154170941 100644
--- a/test/tools/llvm-objdump/elf-dynamic-section.test
+++ b/test/tools/llvm-objdump/elf-dynamic-section.test
@@ -58,6 +58,7 @@
 # CHECK-NEXT:   VERNEEDNUM           0x0000000000000000
 # CHECK-NEXT:   AUXILIARY            D
 # CHECK-NEXT:   FILTER               U
+# CHECK-NEXT:   <unknown:>0x1234abcd 0x0000000000000001
 
 --- !ELF
 FileHeader:
@@ -188,6 +189,8 @@ Sections:
        Value: 0x1
      - Tag:   DT_FILTER
        Value: 0x3
+     - Tag:   0x1234abcd
+       Value: 0x1
      - Tag:   DT_NULL
        Value: 0x0
 ProgramHeaders:
diff --git a/tools/llvm-objdump/ELFDump.cpp b/tools/llvm-objdump/ELFDump.cpp
index 6734f7618e4..c358b428e47 100644
--- a/tools/llvm-objdump/ELFDump.cpp
+++ b/tools/llvm-objdump/ELFDump.cpp
@@ -176,15 +176,8 @@ void printDynamicSection(const ELFFile<ELFT> *Elf, StringRef Filename) {
     if (Dyn.d_tag == ELF::DT_NULL)
       continue;
 
-    StringRef Str = StringRef(Elf->getDynamicTagAsString(Dyn.d_tag));
-
-    if (Str.empty()) {
-      std::string HexStr = utohexstr(static_cast<uint64_t>(Dyn.d_tag), true);
-      outs() << format("  0x%-19s", HexStr.c_str());
-    } else {
-      // We use "-21" in order to match GNU objdump's output.
-      outs() << format("  %-21s", Str.data());
-    }
+    std::string Str = Elf->getDynamicTagAsString(Dyn.d_tag);
+    outs() << format("  %-21s", Str.c_str());
 
     const char *Fmt =
         ELFT::Is64Bits ? "0x%016" PRIx64 "\n" : "0x%08" PRIx64 "\n";
-- 
2.11.0