[llvm-readelf] - Allow dumping of the .dynamic section even if there is no PT_DYNAMIC header.

It is now possible after D61937 was landed and was discussed
in it's review comments. It is not consistent with GNU, which
does not output .dynamic section content in this case for
no visible reason.

Differential revision: https://reviews.llvm.org/D62179

llvm-svn: 361943

1 files changed, 83 insertions, 78 deletions

diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index fcadf73110e..047b463582c 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -1346,6 +1346,7 @@ static const char *getElfMipsOptionsOdkType(unsigned Odk) {
 
 template <typename ELFT>
 void ELFDumper<ELFT>::loadDynamicTable(const ELFFile<ELFT> *Obj) {
+  // Try to locate the PT_DYNAMIC header.
   const Elf_Phdr *DynamicPhdr = nullptr;
   for (const Elf_Phdr &Phdr : unwrapOrError(Obj->program_headers())) {
     if (Phdr.p_type != ELF::PT_DYNAMIC)
@@ -1354,11 +1355,6 @@ void ELFDumper<ELFT>::loadDynamicTable(const ELFFile<ELFT> *Obj) {
     break;
   }
 
-  // We do not want to dump dynamic section if we have no PT_DYNAMIC header.
-  // This matches GNU's behavior.
-  if (!DynamicPhdr)
-    return;
-
   // Try to locate the .dynamic section in the sections header table.
   const Elf_Shdr *DynamicSec = nullptr;
   for (const Elf_Shdr &Sec : unwrapOrError(Obj->sections())) {
@@ -1373,9 +1369,16 @@ void ELFDumper<ELFT>::loadDynamicTable(const ELFFile<ELFT> *Obj) {
   // Ignore sh_entsize and use the expected value for entry size explicitly.
   // This allows us to dump the dynamic sections with a broken sh_entsize
   // field.
-  if (DynamicSec)
+  if (DynamicSec) {
     DynamicTable = checkDRI({ObjF->getELFFile()->base() + DynamicSec->sh_offset,
                              DynamicSec->sh_size, sizeof(Elf_Dyn)});
+    parseDynamicTable();
+  }
+
+  // If we have a PT_DYNAMIC header, we will either check the found dynamic
+  // section or take the dynamic table data directly from the header.
+  if (!DynamicPhdr)
+    return;
 
   if (DynamicPhdr->p_offset + DynamicPhdr->p_filesz >
       ObjF->getMemoryBufferRef().getBufferSize())
@@ -1389,7 +1392,6 @@ void ELFDumper<ELFT>::loadDynamicTable(const ELFFile<ELFT> *Obj) {
   }
 
   StringRef Name = unwrapOrError(Obj->getSectionName(DynamicSec));
-
   if (DynamicSec->sh_addr + DynamicSec->sh_size >
           DynamicPhdr->p_vaddr + DynamicPhdr->p_memsz ||
       DynamicSec->sh_addr < DynamicPhdr->p_vaddr)
@@ -1401,8 +1403,6 @@ void ELFDumper<ELFT>::loadDynamicTable(const ELFFile<ELFT> *Obj) {
     reportWarning("The SHT_DYNAMIC section '" + Name +
                   "' is not at the start of "
                   "PT_DYNAMIC segment");
-
-  parseDynamicTable();
 }
 
 template <typename ELFT>
@@ -1460,11 +1460,71 @@ ELFDumper<ELFT>::ELFDumper(const object::ELFObjectFile<ELFT> *ObjF,
     ELFDumperStyle.reset(new LLVMStyle<ELFT>(Writer, this));
 }
 
+static const char *getTypeString(unsigned Arch, uint64_t Type) {
+#define DYNAMIC_TAG(n, v)
+  switch (Arch) {
+  case EM_HEXAGON:
+    switch (Type) {
+#define HEXAGON_DYNAMIC_TAG(name, value)                                       \
+  case DT_##name:                                                              \
+    return #name;
+#include "llvm/BinaryFormat/DynamicTags.def"
+#undef HEXAGON_DYNAMIC_TAG
+    }
+    break;
+
+  case EM_MIPS:
+    switch (Type) {
+#define MIPS_DYNAMIC_TAG(name, value)                                          \
+  case DT_##name:                                                              \
+    return #name;
+#include "llvm/BinaryFormat/DynamicTags.def"
+#undef MIPS_DYNAMIC_TAG
+    }
+    break;
+
+  case EM_PPC64:
+    switch (Type) {
+#define PPC64_DYNAMIC_TAG(name, value)                                         \
+  case DT_##name:                                                              \
+    return #name;
+#include "llvm/BinaryFormat/DynamicTags.def"
+#undef PPC64_DYNAMIC_TAG
+    }
+    break;
+  }
+#undef DYNAMIC_TAG
+  switch (Type) {
+// Now handle all dynamic tags except the architecture specific ones
+#define MIPS_DYNAMIC_TAG(name, value)
+#define HEXAGON_DYNAMIC_TAG(name, value)
+#define PPC64_DYNAMIC_TAG(name, value)
+// Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
+#define DYNAMIC_TAG_MARKER(name, value)
+#define DYNAMIC_TAG(name, value)                                               \
+  case DT_##name:                                                              \
+    return #name;
+#include "llvm/BinaryFormat/DynamicTags.def"
+#undef DYNAMIC_TAG
+#undef MIPS_DYNAMIC_TAG
+#undef HEXAGON_DYNAMIC_TAG
+#undef PPC64_DYNAMIC_TAG
+#undef DYNAMIC_TAG_MARKER
+  default:
+    return "unknown";
+  }
+}
+
 template <typename ELFT> void ELFDumper<ELFT>::parseDynamicTable() {
-  auto toMappedAddr = [&](uint64_t VAddr) -> const uint8_t * {
+  auto toMappedAddr = [&](uint64_t Tag, uint64_t VAddr) -> const uint8_t * {
     auto MappedAddrOrError = ObjF->getELFFile()->toMappedAddr(VAddr);
-    if (!MappedAddrOrError)
-      report_fatal_error(MappedAddrOrError.takeError());
+    if (!MappedAddrOrError) {
+      reportWarning("Unable to parse DT_" +
+                    Twine(getTypeString(
+                        ObjF->getELFFile()->getHeader()->e_machine, Tag)) +
+                    ": " + llvm::toString(MappedAddrOrError.takeError()));
+      return nullptr;
+    }
     return MappedAddrOrError.get();
   };
 
@@ -1474,26 +1534,26 @@ template <typename ELFT> void ELFDumper<ELFT>::parseDynamicTable() {
   for (const Elf_Dyn &Dyn : dynamic_table()) {
     switch (Dyn.d_tag) {
     case ELF::DT_HASH:
-      HashTable =
-          reinterpret_cast<const Elf_Hash *>(toMappedAddr(Dyn.getPtr()));
+      HashTable = reinterpret_cast<const Elf_Hash *>(
+          toMappedAddr(Dyn.getTag(), Dyn.getPtr()));
       break;
     case ELF::DT_GNU_HASH:
-      GnuHashTable =
-          reinterpret_cast<const Elf_GnuHash *>(toMappedAddr(Dyn.getPtr()));
+      GnuHashTable = reinterpret_cast<const Elf_GnuHash *>(
+          toMappedAddr(Dyn.getTag(), Dyn.getPtr()));
       break;
     case ELF::DT_STRTAB:
-      StringTableBegin =
-          reinterpret_cast<const char *>(toMappedAddr(Dyn.getPtr()));
+      StringTableBegin = reinterpret_cast<const char *>(
+          toMappedAddr(Dyn.getTag(), Dyn.getPtr()));
       break;
     case ELF::DT_STRSZ:
       StringTableSize = Dyn.getVal();
       break;
     case ELF::DT_SYMTAB:
-      DynSymRegion.Addr = toMappedAddr(Dyn.getPtr());
+      DynSymRegion.Addr = toMappedAddr(Dyn.getTag(), Dyn.getPtr());
       DynSymRegion.EntSize = sizeof(Elf_Sym);
       break;
     case ELF::DT_RELA:
-      DynRelaRegion.Addr = toMappedAddr(Dyn.getPtr());
+      DynRelaRegion.Addr = toMappedAddr(Dyn.getTag(), Dyn.getPtr());
       break;
     case ELF::DT_RELASZ:
       DynRelaRegion.Size = Dyn.getVal();
@@ -1505,7 +1565,7 @@ template <typename ELFT> void ELFDumper<ELFT>::parseDynamicTable() {
       SONameOffset = Dyn.getVal();
       break;
     case ELF::DT_REL:
-      DynRelRegion.Addr = toMappedAddr(Dyn.getPtr());
+      DynRelRegion.Addr = toMappedAddr(Dyn.getTag(), Dyn.getPtr());
       break;
     case ELF::DT_RELSZ:
       DynRelRegion.Size = Dyn.getVal();
@@ -1515,7 +1575,7 @@ template <typename ELFT> void ELFDumper<ELFT>::parseDynamicTable() {
       break;
     case ELF::DT_RELR:
     case ELF::DT_ANDROID_RELR:
-      DynRelrRegion.Addr = toMappedAddr(Dyn.getPtr());
+      DynRelrRegion.Addr = toMappedAddr(Dyn.getTag(), Dyn.getPtr());
       break;
     case ELF::DT_RELRSZ:
     case ELF::DT_ANDROID_RELRSZ:
@@ -1535,7 +1595,7 @@ template <typename ELFT> void ELFDumper<ELFT>::parseDynamicTable() {
                     Twine((uint64_t)Dyn.getVal()));
       break;
     case ELF::DT_JMPREL:
-      DynPLTRelRegion.Addr = toMappedAddr(Dyn.getPtr());
+      DynPLTRelRegion.Addr = toMappedAddr(Dyn.getTag(), Dyn.getPtr());
       break;
     case ELF::DT_PLTRELSZ:
       DynPLTRelRegion.Size = Dyn.getVal();
@@ -1627,61 +1687,6 @@ template <class ELFT> void ELFDumper<ELFT>::printELFLinkerOptions() {
   ELFDumperStyle->printELFLinkerOptions(ObjF->getELFFile());
 }
 
-static const char *getTypeString(unsigned Arch, uint64_t Type) {
-#define DYNAMIC_TAG(n, v)
-  switch (Arch) {
-  case EM_HEXAGON:
-    switch (Type) {
-#define HEXAGON_DYNAMIC_TAG(name, value)                                       \
-    case DT_##name:                                                            \
-      return #name;
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef HEXAGON_DYNAMIC_TAG
-    }
-    break;
-
-  case EM_MIPS:
-    switch (Type) {
-#define MIPS_DYNAMIC_TAG(name, value)                                          \
-    case DT_##name:                                                            \
-      return #name;
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef MIPS_DYNAMIC_TAG
-    }
-    break;
-
-  case EM_PPC64:
-    switch(Type) {
-#define PPC64_DYNAMIC_TAG(name, value)                                         \
-    case DT_##name:                                                            \
-      return #name;
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef PPC64_DYNAMIC_TAG
-    }
-    break;
-  }
-#undef DYNAMIC_TAG
-  switch (Type) {
-// Now handle all dynamic tags except the architecture specific ones
-#define MIPS_DYNAMIC_TAG(name, value)
-#define HEXAGON_DYNAMIC_TAG(name, value)
-#define PPC64_DYNAMIC_TAG(name, value)
-// Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
-#define DYNAMIC_TAG_MARKER(name, value)
-#define DYNAMIC_TAG(name, value)                                               \
-  case DT_##name:                                                              \
-    return #name;
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef DYNAMIC_TAG
-#undef MIPS_DYNAMIC_TAG
-#undef HEXAGON_DYNAMIC_TAG
-#undef PPC64_DYNAMIC_TAG
-#undef DYNAMIC_TAG_MARKER
-  default:
-    return "unknown";
-  }
-}
-
 #define LLVM_READOBJ_DT_FLAG_ENT(prefix, enum)                                 \
   { #enum, prefix##_##enum }