1 files changed, 71 insertions, 30 deletions

diff --git a/include/llvm/Object/ELF.h b/include/llvm/Object/ELF.h
index 3b0c548..cc27185 100644
--- a/include/llvm/Object/ELF.h
+++ b/include/llvm/Object/ELF.h
@@ -16,6 +16,7 @@
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/IntervalMap.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -139,6 +140,7 @@ public:
   typedef Elf_Verneed_Impl<ELFT> Elf_Verneed;
   typedef Elf_Vernaux_Impl<ELFT> Elf_Vernaux;
   typedef Elf_Versym_Impl<ELFT> Elf_Versym;
+  typedef Elf_Hash_Impl<ELFT> Elf_Hash;
   typedef ELFEntityIterator<const Elf_Dyn> Elf_Dyn_Iter;
   typedef iterator_range<Elf_Dyn_Iter> Elf_Dyn_Range;
   typedef ELFEntityIterator<const Elf_Rela> Elf_Rela_Iter;
@@ -174,8 +176,8 @@ private:
   StringRef DotShstrtab;                    // Section header string table.
   StringRef DotStrtab;                      // Symbol header string table.
   const Elf_Shdr *dot_symtab_sec = nullptr; // Symbol table section.
-  StringRef DynSymStrTab;                   // Dynnamic symbol string table.
   const Elf_Shdr *DotDynSymSec = nullptr;   // Dynamic symbol table section.
+  const Elf_Hash *HashTable = nullptr;
 
   const Elf_Shdr *SymbolTableSectionHeaderIndex = nullptr;
   DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
@@ -197,6 +199,7 @@ private:
 
   DynRegionInfo DynamicRegion;
   DynRegionInfo DynHashRegion;
+  DynRegionInfo DynStrRegion;
   DynRegionInfo DynRelaRegion;
 
   // Pointer to SONAME entry in dynamic string table
@@ -229,6 +232,8 @@ private:
   void LoadVersionNeeds(const Elf_Shdr *ec) const;
   void LoadVersionMap() const;
 
+  void scanDynamicTable();
+
 public:
   template<typename T>
   const T        *getEntry(uint32_t Section, uint32_t Entry) const;
@@ -237,6 +242,7 @@ public:
 
   const Elf_Shdr *getDotSymtabSec() const { return dot_symtab_sec; }
   const Elf_Shdr *getDotDynSymSec() const { return DotDynSymSec; }
+  const Elf_Hash *getHashTable() const { return HashTable; }
 
   ErrorOr<StringRef> getStringTable(const Elf_Shdr *Section) const;
   const char *getDynamicString(uintX_t Offset) const;
@@ -578,8 +584,10 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
 
   Header = reinterpret_cast<const Elf_Ehdr *>(base());
 
-  if (Header->e_shoff == 0)
+  if (Header->e_shoff == 0) {
+    scanDynamicTable();
     return;
+  }
 
   const uint64_t SectionTableOffset = Header->e_shoff;
 
@@ -604,6 +612,13 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
 
   for (const Elf_Shdr &Sec : sections()) {
     switch (Sec.sh_type) {
+    case ELF::SHT_HASH:
+      if (HashTable) {
+        EC = object_error::parse_failed;
+        return;
+      }
+      HashTable = reinterpret_cast<const Elf_Hash *>(base() + Sec.sh_offset);
+      break;
     case ELF::SHT_SYMTAB_SHNDX:
       if (SymbolTableSectionHeaderIndex) {
         // More than one .symtab_shndx!
@@ -640,7 +655,9 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
       ErrorOr<StringRef> SymtabOrErr = getStringTable(*SectionOrErr);
       if ((EC = SymtabOrErr.getError()))
         return;
-      DynSymStrTab = *SymtabOrErr;
+      DynStrRegion.Addr = SymtabOrErr->data();
+      DynStrRegion.Size = SymtabOrErr->size();
+      DynStrRegion.EntSize = 1;
       break;
     }
     case ELF::SHT_DYNAMIC:
@@ -701,7 +718,23 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
     }
   }
 
-  // Scan program headers.
+  scanDynamicTable();
+
+  EC = std::error_code();
+}
+
+template <class ELFT>
+void ELFFile<ELFT>::scanDynamicTable() {
+  // Build load-address to file-offset map.
+  typedef IntervalMap<
+      uintX_t, uintptr_t,
+      IntervalMapImpl::NodeSizer<uintX_t, uintptr_t>::LeafSize,
+      IntervalMapHalfOpenInfo<uintX_t>> LoadMapT;
+  typename LoadMapT::Allocator Alloc;
+  // Allocate the IntervalMap on the heap to work around MSVC bug where the
+  // stack doesn't get realigned despite LoadMap having alignment 8 (PR24113).
+  std::unique_ptr<LoadMapT> LoadMap(new LoadMapT(Alloc));
+
   for (Elf_Phdr_Iter PhdrI = program_header_begin(),
                      PhdrE = program_header_end();
        PhdrI != PhdrE; ++PhdrI) {
@@ -709,34 +742,44 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
       DynamicRegion.Addr = base() + PhdrI->p_offset;
       DynamicRegion.Size = PhdrI->p_filesz;
       DynamicRegion.EntSize = sizeof(Elf_Dyn);
-      break;
+      continue;
     }
+    if (PhdrI->p_type != ELF::PT_LOAD)
+      continue;
+    if (PhdrI->p_filesz == 0)
+      continue;
+    LoadMap->insert(PhdrI->p_vaddr, PhdrI->p_vaddr + PhdrI->p_filesz,
+                    PhdrI->p_offset);
   }
 
-  // Scan dynamic table.
+  auto toMappedAddr = [&](uint64_t VAddr) -> const uint8_t * {
+    auto I = LoadMap->find(VAddr);
+    if (I == LoadMap->end())
+      return nullptr;
+    return this->base() + I.value() + (VAddr - I.start());
+  };
+
   for (Elf_Dyn_Iter DynI = dynamic_table_begin(), DynE = dynamic_table_end();
        DynI != DynE; ++DynI) {
     switch (DynI->d_tag) {
-    case ELF::DT_RELA: {
-      uint64_t VBase = 0;
-      const uint8_t *FBase = nullptr;
-      for (Elf_Phdr_Iter PhdrI = program_header_begin(),
-                         PhdrE = program_header_end();
-           PhdrI != PhdrE; ++PhdrI) {
-        if (PhdrI->p_type != ELF::PT_LOAD)
-          continue;
-        if (DynI->getPtr() >= PhdrI->p_vaddr &&
-            DynI->getPtr() < PhdrI->p_vaddr + PhdrI->p_memsz) {
-          VBase = PhdrI->p_vaddr;
-          FBase = base() + PhdrI->p_offset;
-          break;
-        }
-      }
-      if (!VBase)
-        return;
-      DynRelaRegion.Addr = FBase + DynI->getPtr() - VBase;
+    case ELF::DT_HASH:
+      if (HashTable)
+        continue;
+      HashTable =
+          reinterpret_cast<const Elf_Hash *>(toMappedAddr(DynI->getPtr()));
+      break;
+    case ELF::DT_STRTAB:
+      if (!DynStrRegion.Addr)
+        DynStrRegion.Addr = toMappedAddr(DynI->getPtr());
+      break;
+    case ELF::DT_STRSZ:
+      if (!DynStrRegion.Size)
+        DynStrRegion.Size = DynI->getVal();
+      break;
+    case ELF::DT_RELA:
+      if (!DynRelaRegion.Addr)
+        DynRelaRegion.Addr = toMappedAddr(DynI->getPtr());
       break;
-    }
     case ELF::DT_RELASZ:
       DynRelaRegion.Size = DynI->getVal();
       break;
@@ -744,8 +787,6 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
       DynRelaRegion.EntSize = DynI->getVal();
     }
   }
-
-  EC = std::error_code();
 }
 
 template <class ELFT>
@@ -868,9 +909,9 @@ ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
 
 template <class ELFT>
 const char *ELFFile<ELFT>::getDynamicString(uintX_t Offset) const {
-  if (!DotDynSymSec || Offset >= DynSymStrTab.size())
+  if (Offset >= DynStrRegion.Size)
     return nullptr;
-  return (const char *)DynSymStrTab.begin() + Offset;
+  return (const char *)DynStrRegion.Addr + Offset;
 }
 
 template <class ELFT>
@@ -983,7 +1024,7 @@ ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
     IsDefault = false;
   }
 
-  if (name_offset >= DynSymStrTab.size())
+  if (name_offset >= DynStrRegion.Size)
     return object_error::parse_failed;
   return StringRef(getDynamicString(name_offset));
 }