Switch <elf.h> over to linux uapi under the covers.

Remove the linker's reliance on BSD cruft and use the glibc-style
ElfW macro. (Other code too, but the linker contains the majority
of the code that needs to work for Elf32 and Elf64.)

All platforms need dl_iterate_phdr_static, so it doesn't make sense
to have that part of the per-architecture configuration.

Bug: 12476126
Change-Id: I1d7f918f1303a392794a6cd8b3512ff56bd6e487

5 files changed, 405 insertions, 437 deletions

diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp
index 1e9d9bc..14ce113 100644
--- a/linker/dlfcn.cpp
+++ b/linker/dlfcn.cpp
@@ -87,7 +87,7 @@ void* dlsym(void* handle, const char* symbol) {
   }
 
   soinfo* found = NULL;
-  Elf_Sym* sym = NULL;
+  ElfW(Sym)* sym = NULL;
   if (handle == RTLD_DEFAULT) {
     sym = dlsym_linear_lookup(symbol, &found, NULL);
   } else if (handle == RTLD_NEXT) {
@@ -134,7 +134,7 @@ int dladdr(const void* addr, Dl_info* info) {
   info->dli_fbase = (void*) si->base;
 
   // Determine if any symbol in the library contains the specified address.
-  Elf_Sym *sym = dladdr_find_symbol(si, addr);
+  ElfW(Sym)* sym = dladdr_find_symbol(si, addr);
   if (sym != NULL) {
     info->dli_sname = si->strtab + sym->st_name;
     info->dli_saddr = (void*)(si->load_bias + sym->st_value);
@@ -167,12 +167,6 @@ int dlclose(void* handle) {
       /* st_size */ 0, \
     }
 
-#if defined(__LP64__)
-#  define ELF_SYM_INITIALIZER ELF64_SYM_INITIALIZER
-#else
-#  define ELF_SYM_INITIALIZER ELF32_SYM_INITIALIZER
-#endif
-
 #if defined(__arm__)
   // 0000000 00011111 111112 22222222 2333333 3333444444444455555555556666666 6667777777777888888888899999 9999900000000001 1
   // 0123456 78901234 567890 12345678 9012345 6789012345678901234567890123456 7890123456789012345678901234 5678901234567890 1
@@ -187,22 +181,22 @@ int dlclose(void* handle) {
 #  error Unsupported architecture. Only arm, arm64, mips, x86, and x86_64 are presently supported.
 #endif
 
-static Elf_Sym gLibDlSymtab[] = {
+static ElfW(Sym) gLibDlSymtab[] = {
   // Total length of libdl_info.strtab, including trailing 0.
   // This is actually the STH_UNDEF entry. Technically, it's
   // supposed to have st_name == 0, but instead, it points to an index
   // in the strtab with a \0 to make iterating through the symtab easier.
-  ELF_SYM_INITIALIZER(sizeof(ANDROID_LIBDL_STRTAB) - 1, NULL, 0),
-  ELF_SYM_INITIALIZER(  0, &dlopen, 1),
-  ELF_SYM_INITIALIZER(  7, &dlclose, 1),
-  ELF_SYM_INITIALIZER( 15, &dlsym, 1),
-  ELF_SYM_INITIALIZER( 21, &dlerror, 1),
-  ELF_SYM_INITIALIZER( 29, &dladdr, 1),
-  ELF_SYM_INITIALIZER( 36, &android_update_LD_LIBRARY_PATH, 1),
-  ELF_SYM_INITIALIZER( 67, &android_get_LD_LIBRARY_PATH, 1),
-  ELF_SYM_INITIALIZER( 95, &dl_iterate_phdr, 1),
+  ELFW(SYM_INITIALIZER)(sizeof(ANDROID_LIBDL_STRTAB) - 1, NULL, 0),
+  ELFW(SYM_INITIALIZER)(  0, &dlopen, 1),
+  ELFW(SYM_INITIALIZER)(  7, &dlclose, 1),
+  ELFW(SYM_INITIALIZER)( 15, &dlsym, 1),
+  ELFW(SYM_INITIALIZER)( 21, &dlerror, 1),
+  ELFW(SYM_INITIALIZER)( 29, &dladdr, 1),
+  ELFW(SYM_INITIALIZER)( 36, &android_update_LD_LIBRARY_PATH, 1),
+  ELFW(SYM_INITIALIZER)( 67, &android_get_LD_LIBRARY_PATH, 1),
+  ELFW(SYM_INITIALIZER)( 95, &dl_iterate_phdr, 1),
 #if defined(__arm__)
-  ELF_SYM_INITIALIZER(111, &dl_unwind_find_exidx, 1),
+  ELFW(SYM_INITIALIZER)(111, &dl_unwind_find_exidx, 1),
 #endif
 };
 
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 2058050..a133d1b 100755
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -29,9 +29,8 @@
 #include <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <linux/auxvec.h>
+#include <inttypes.h>
 #include <pthread.h>
-#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -67,7 +66,7 @@
  */
 
 static bool soinfo_link_image(soinfo* si);
-static Elf_Addr get_elf_exec_load_bias(const Elf_Ehdr* elf);
+static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf);
 
 // We can't use malloc(3) in the dynamic linker. We use a linked list of anonymous
 // maps, each a single page in size. The pages are broken up into as many struct soinfo
@@ -451,33 +450,33 @@ dl_iterate_phdr(int (*cb)(dl_phdr_info *info, size_t size, void *data),
     return rv;
 }
 
-static Elf_Sym* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name) {
-    Elf_Sym* symtab = si->symtab;
-    const char* strtab = si->strtab;
+static ElfW(Sym)* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name) {
+  ElfW(Sym)* symtab = si->symtab;
+  const char* strtab = si->strtab;
 
-    TRACE_TYPE(LOOKUP, "SEARCH %s in %s@%p %x %zd",
-               name, si->name, reinterpret_cast<void*>(si->base), hash, hash % si->nbucket);
+  TRACE_TYPE(LOOKUP, "SEARCH %s in %s@%p %x %zd",
+             name, si->name, reinterpret_cast<void*>(si->base), hash, hash % si->nbucket);
 
-    for (unsigned n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]) {
-        Elf_Sym* s = symtab + n;
-        if (strcmp(strtab + s->st_name, name)) continue;
+  for (unsigned n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]) {
+    ElfW(Sym)* s = symtab + n;
+    if (strcmp(strtab + s->st_name, name)) continue;
 
-            /* only concern ourselves with global and weak symbol definitions */
-        switch (ELF_ST_BIND(s->st_info)) {
-        case STB_GLOBAL:
-        case STB_WEAK:
-            if (s->st_shndx == SHN_UNDEF) {
-                continue;
-            }
+    /* only concern ourselves with global and weak symbol definitions */
+    switch (ELF_ST_BIND(s->st_info)) {
+      case STB_GLOBAL:
+      case STB_WEAK:
+        if (s->st_shndx == SHN_UNDEF) {
+        continue;
+      }
 
-            TRACE_TYPE(LOOKUP, "FOUND %s in %s (%p) %zd",
-                       name, si->name, reinterpret_cast<void*>(s->st_value),
-                       static_cast<size_t>(s->st_size));
-            return s;
-        }
+      TRACE_TYPE(LOOKUP, "FOUND %s in %s (%p) %zd",
+                 name, si->name, reinterpret_cast<void*>(s->st_value),
+                 static_cast<size_t>(s->st_size));
+      return s;
     }
+  }
 
-    return NULL;
+  return NULL;
 }
 
 static unsigned elfhash(const char* _name) {
@@ -493,9 +492,9 @@ static unsigned elfhash(const char* _name) {
     return h;
 }
 
-static Elf_Sym* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, soinfo* needed[]) {
+static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, soinfo* needed[]) {
     unsigned elf_hash = elfhash(name);
-    Elf_Sym* s = NULL;
+    ElfW(Sym)* s = NULL;
 
     if (si != NULL && somain != NULL) {
 
@@ -603,7 +602,7 @@ done:
    Binary Interface) where in Chapter 5 it discuss resolving "Shared
    Object Dependencies" in breadth first search order.
  */
-Elf_Sym* dlsym_handle_lookup(soinfo* si, const char* name) {
+ElfW(Sym)* dlsym_handle_lookup(soinfo* si, const char* name) {
     return soinfo_elf_lookup(si, elfhash(name), name);
 }
 
@@ -612,14 +611,14 @@ Elf_Sym* dlsym_handle_lookup(soinfo* si, const char* name) {
    beginning of the global solist. Otherwise the search starts at the
    specified soinfo (for RTLD_NEXT).
  */
-Elf_Sym* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start) {
+ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start) {
   unsigned elf_hash = elfhash(name);
 
   if (start == NULL) {
     start = solist;
   }
 
-  Elf_Sym* s = NULL;
+  ElfW(Sym)* s = NULL;
   for (soinfo* si = start; (s == NULL) && (si != NULL); si = si->next) {
     s = soinfo_elf_lookup(si, elf_hash, name);
     if (s != NULL) {
@@ -637,7 +636,7 @@ Elf_Sym* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start) {
 }
 
 soinfo* find_containing_library(const void* p) {
-  Elf_Addr address = reinterpret_cast<Elf_Addr>(p);
+  ElfW(Addr) address = reinterpret_cast<ElfW(Addr)>(p);
   for (soinfo* si = solist; si != NULL; si = si->next) {
     if (address >= si->base && address - si->base < si->size) {
       return si;
@@ -646,13 +645,13 @@ soinfo* find_containing_library(const void* p) {
   return NULL;
 }
 
-Elf_Sym* dladdr_find_symbol(soinfo* si, const void* addr) {
-  Elf_Addr soaddr = reinterpret_cast<Elf_Addr>(addr) - si->base;
+ElfW(Sym)* dladdr_find_symbol(soinfo* si, const void* addr) {
+  ElfW(Addr) soaddr = reinterpret_cast<ElfW(Addr)>(addr) - si->base;
 
   // Search the library's symbol table for any defined symbol which
   // contains this address.
   for (size_t i = 0; i < si->nchain; ++i) {
-    Elf_Sym* sym = &si->symtab[i];
+    ElfW(Sym)* sym = &si->symtab[i];
     if (sym->st_shndx != SHN_UNDEF &&
         soaddr >= sym->st_value &&
         soaddr < sym->st_value + sym->st_size) {
@@ -666,13 +665,13 @@ Elf_Sym* dladdr_find_symbol(soinfo* si, const void* addr) {
 #if 0
 static void dump(soinfo* si)
 {
-    Elf_Sym* s = si->symtab;
-    for (unsigned n = 0; n < si->nchain; n++) {
-        TRACE("%04d> %08x: %02x %04x %08x %08x %s", n, s,
-               s->st_info, s->st_shndx, s->st_value, s->st_size,
-               si->strtab + s->st_name);
-        s++;
-    }
+  ElfW(Sym)* s = si->symtab;
+  for (unsigned n = 0; n < si->nchain; n++) {
+    TRACE("%04d> %08x: %02x %04x %08x %08x %s", n, s,
+          s->st_info, s->st_shndx, s->st_value, s->st_size,
+          si->strtab + s->st_name);
+    s++;
+  }
 }
 #endif
 
@@ -808,7 +807,7 @@ static int soinfo_unload(soinfo* si) {
     TRACE("unloading '%s'", si->name);
     si->CallDestructors();
 
-    for (Elf_Dyn* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
+    for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
       if (d->d_tag == DT_NEEDED) {
         const char* library_name = si->strtab + d->d_un.d_val;
         TRACE("%s needs to unload %s", si->name, library_name);
@@ -859,18 +858,18 @@ int do_dlclose(soinfo* si) {
 }
 
 #if defined(USE_RELA)
-static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo* needed[]) {
-  Elf_Sym* symtab = si->symtab;
+static int soinfo_relocate_a(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo* needed[]) {
+  ElfW(Sym)* symtab = si->symtab;
   const char* strtab = si->strtab;
-  Elf_Sym* s;
-  Elf_Rela* start = rela;
+  ElfW(Sym)* s;
+  ElfW(Rela)* start = rela;
   soinfo* lsi;
 
   for (size_t idx = 0; idx < count; ++idx, ++rela) {
-    unsigned type = ELF_R_TYPE(rela->r_info);
-    unsigned sym = ELF_R_SYM(rela->r_info);
-    Elf_Addr reloc = static_cast<Elf_Addr>(rela->r_offset + si->load_bias);
-    Elf_Addr sym_addr = 0;
+    unsigned type = ELFW(R_TYPE)(rela->r_info);
+    unsigned sym = ELFW(R_SYM)(rela->r_info);
+    ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rela->r_offset + si->load_bias);
+    ElfW(Addr) sym_addr = 0;
     char* sym_name = NULL;
 
     DEBUG("Processing '%s' relocation at index %zd", si->name, idx);
@@ -931,7 +930,7 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
         }
       } else {
         // We got a definition.
-        sym_addr = static_cast<Elf_Addr>(s->st_value + lsi->load_bias);
+        sym_addr = static_cast<ElfW(Addr)>(s->st_value + lsi->load_bias);
       }
       count_relocation(kRelocSymbol);
     } else {
@@ -943,117 +942,92 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
     case R_AARCH64_JUMP_SLOT:
         count_relocation(kRelocAbsolute);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO JMP_SLOT %16lx <- %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    sym_name);
-        *reinterpret_cast<Elf_Addr*>(reloc) = (sym_addr + rela->r_addend);
+        TRACE_TYPE(RELO, "RELO JMP_SLOT %16llx <- %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), sym_name);
+        *reinterpret_cast<ElfW(Addr)*>(reloc) = (sym_addr + rela->r_addend);
         break;
     case R_AARCH64_GLOB_DAT:
         count_relocation(kRelocAbsolute);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO GLOB_DAT %16lx <- %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    sym_name);
-        *reinterpret_cast<Elf_Addr*>(reloc) = (sym_addr + rela->r_addend);
+        TRACE_TYPE(RELO, "RELO GLOB_DAT %16llx <- %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), sym_name);
+        *reinterpret_cast<ElfW(Addr)*>(reloc) = (sym_addr + rela->r_addend);
         break;
     case R_AARCH64_ABS64:
         count_relocation(kRelocAbsolute);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO ABS64 %16lx <- %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    sym_name);
-        *reinterpret_cast<Elf_Addr*>(reloc) += (sym_addr + rela->r_addend);
+        TRACE_TYPE(RELO, "RELO ABS64 %16llx <- %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), sym_name);
+        *reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend);
         break;
     case R_AARCH64_ABS32:
         count_relocation(kRelocAbsolute);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO ABS32 %16lx <- %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    sym_name);
-        if ((static_cast<Elf_Addr>(INT32_MIN) <=
-          (*reinterpret_cast<Elf_Addr*>(reloc) + (sym_addr + rela->r_addend))) &&
-          ((*reinterpret_cast<Elf_Addr*>(reloc) + (sym_addr + rela->r_addend)) <=
-          static_cast<Elf_Addr>(UINT32_MAX))) {
-            *reinterpret_cast<Elf_Addr*>(reloc) += (sym_addr + rela->r_addend);
+        TRACE_TYPE(RELO, "RELO ABS32 %16llx <- %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), sym_name);
+        if ((static_cast<ElfW(Addr)>(INT32_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend))) &&
+            ((*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)) <= static_cast<ElfW(Addr)>(UINT32_MAX))) {
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend);
         } else {
-            DL_ERR("0x%016lx out of range 0x%016lx to 0x%016lx",
-                    (*reinterpret_cast<Elf_Addr*>(reloc) + (sym_addr + rela->r_addend)),
-                    static_cast<Elf_Addr>(INT32_MIN),
-                    static_cast<Elf_Addr>(UINT32_MAX));
+            DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
+                   (*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)),
+                   static_cast<ElfW(Addr)>(INT32_MIN),
+                   static_cast<ElfW(Addr)>(UINT32_MAX));
             return -1;
         }
         break;
     case R_AARCH64_ABS16:
         count_relocation(kRelocAbsolute);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO ABS16 %16lx <- %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    sym_name);
-        if ((static_cast<Elf_Addr>(INT16_MIN) <=
-          (*reinterpret_cast<Elf_Addr*>(reloc) + (sym_addr + rela->r_addend))) &&
-          ((*reinterpret_cast<Elf_Addr*>(reloc) + (sym_addr + rela->r_addend)) <=
-          static_cast<Elf_Addr>(UINT16_MAX))) {
-            *reinterpret_cast<Elf_Addr*>(reloc) += (sym_addr + rela->r_addend);
+        TRACE_TYPE(RELO, "RELO ABS16 %16llx <- %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), sym_name);
+        if ((static_cast<ElfW(Addr)>(INT16_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend))) &&
+            ((*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)) <= static_cast<ElfW(Addr)>(UINT16_MAX))) {
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend);
         } else {
-            DL_ERR("0x%016lx out of range 0x%016lx to 0x%016lx",
-                    (*reinterpret_cast<Elf_Addr*>(reloc) + (sym_addr + rela->r_addend)),
-                    static_cast<Elf_Addr>(INT16_MIN),
-                    static_cast<Elf_Addr>(UINT16_MAX));
+            DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
+                   (*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)),
+                   static_cast<ElfW(Addr)>(INT16_MIN),
+                   static_cast<ElfW(Addr)>(UINT16_MAX));
             return -1;
         }
         break;
     case R_AARCH64_PREL64:
         count_relocation(kRelocRelative);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO REL64 %16lx <- %16lx - %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    rela->r_offset,
-                    sym_name);
-        *reinterpret_cast<Elf_Addr*>(reloc) += (sym_addr + rela->r_addend) - rela->r_offset;
+        TRACE_TYPE(RELO, "RELO REL64 %16llx <- %16llx - %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), rela->r_offset, sym_name);
+        *reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend) - rela->r_offset;
         break;
     case R_AARCH64_PREL32:
         count_relocation(kRelocRelative);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO REL32 %16lx <- %16lx - %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    rela->r_offset, sym_name);
-        if ((static_cast<Elf_Addr>(INT32_MIN) <=
-          (*reinterpret_cast<Elf_Addr*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset))) &&
-          ((*reinterpret_cast<Elf_Addr*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)) <=
-          static_cast<Elf_Addr>(UINT32_MAX))) {
-            *reinterpret_cast<Elf_Addr*>(reloc) += ((sym_addr + rela->r_addend) - rela->r_offset);
+        TRACE_TYPE(RELO, "RELO REL32 %16llx <- %16llx - %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), rela->r_offset, sym_name);
+        if ((static_cast<ElfW(Addr)>(INT32_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset))) &&
+            ((*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)) <= static_cast<ElfW(Addr)>(UINT32_MAX))) {
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += ((sym_addr + rela->r_addend) - rela->r_offset);
         } else {
-            DL_ERR("0x%016lx out of range 0x%016lx to 0x%016lx",
-                    (*reinterpret_cast<Elf_Addr*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)),
-                    static_cast<Elf_Addr>(INT32_MIN),
-                    static_cast<Elf_Addr>(UINT32_MAX));
+            DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
+                   (*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)),
+                   static_cast<ElfW(Addr)>(INT32_MIN),
+                   static_cast<ElfW(Addr)>(UINT32_MAX));
             return -1;
         }
         break;
     case R_AARCH64_PREL16:
         count_relocation(kRelocRelative);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO REL16 %16lx <- %16lx - %16lx %s\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    rela->r_offset, sym_name);
-        if ((static_cast<Elf_Addr>(INT16_MIN) <=
-          (*reinterpret_cast<Elf_Addr*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset))) &&
-          ((*reinterpret_cast<Elf_Addr*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)) <=
-          static_cast<Elf_Addr>(UINT16_MAX))) {
-            *reinterpret_cast<Elf_Addr*>(reloc) += ((sym_addr + rela->r_addend) - rela->r_offset);
+        TRACE_TYPE(RELO, "RELO REL16 %16llx <- %16llx - %16llx %s\n",
+                   reloc, (sym_addr + rela->r_addend), rela->r_offset, sym_name);
+        if ((static_cast<ElfW(Addr)>(INT16_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset))) &&
+            ((*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)) <= static_cast<ElfW(Addr)>(UINT16_MAX))) {
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += ((sym_addr + rela->r_addend) - rela->r_offset);
         } else {
-            DL_ERR("0x%016lx out of range 0x%016lx to 0x%016lx",
-                    (*reinterpret_cast<Elf_Addr*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)),
-                    static_cast<Elf_Addr>(INT16_MIN),
-                    static_cast<Elf_Addr>(UINT16_MAX));
+            DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
+                   (*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)),
+                   static_cast<ElfW(Addr)>(INT16_MIN),
+                   static_cast<ElfW(Addr)>(UINT16_MAX));
             return -1;
         }
         break;
@@ -1065,10 +1039,9 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
             DL_ERR("odd RELATIVE form...");
             return -1;
         }
-        TRACE_TYPE(RELO, "RELO RELATIVE %16lx <- %16lx\n",
-                    reloc,
-                    (si->base + rela->r_addend));
-        *reinterpret_cast<Elf_Addr*>(reloc) = (si->base + rela->r_addend);
+        TRACE_TYPE(RELO, "RELO RELATIVE %16llx <- %16llx\n",
+                   reloc, (si->base + rela->r_addend));
+        *reinterpret_cast<ElfW(Addr)*>(reloc) = (si->base + rela->r_addend);
         break;
 
     case R_AARCH64_COPY:
@@ -1089,13 +1062,13 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
         }
         count_relocation(kRelocCopy);
         MARK(rela->r_offset);
-        TRACE_TYPE(RELO, "RELO COPY %16lx <- %ld @ %16lx %s\n",
-                    reloc,
-                    s->st_size,
-                    (sym_addr + rela->r_addend),
-                    sym_name);
+        TRACE_TYPE(RELO, "RELO COPY %16llx <- %lld @ %16llx %s\n",
+                   reloc,
+                   s->st_size,
+                   (sym_addr + rela->r_addend),
+                   sym_name);
         if (reloc == (sym_addr + rela->r_addend)) {
-            Elf_Sym *src = soinfo_do_lookup(NULL, sym_name, &lsi, needed);
+            ElfW(Sym)* src = soinfo_do_lookup(NULL, sym_name, &lsi, needed);
 
             if (src == NULL) {
                 DL_ERR("%s R_AARCH64_COPY relocation source cannot be resolved", si->name);
@@ -1103,12 +1076,12 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
             }
             if (lsi->has_DT_SYMBOLIC) {
                 DL_ERR("%s invalid R_AARCH64_COPY relocation against DT_SYMBOLIC shared "
-                        "library %s (built with -Bsymbolic?)", si->name, lsi->name);
+                       "library %s (built with -Bsymbolic?)", si->name, lsi->name);
                 return -1;
             }
             if (s->st_size < src->st_size) {
-                DL_ERR("%s R_AARCH64_COPY relocation size mismatch (%ld < %ld)",
-                        si->name, s->st_size, src->st_size);
+                DL_ERR("%s R_AARCH64_COPY relocation size mismatch (%lld < %lld)",
+                       si->name, s->st_size, src->st_size);
                 return -1;
             }
             memcpy((void*)reloc, (void*)(src->st_value + lsi->load_bias), src->st_size);
@@ -1118,16 +1091,12 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
         }
         break;
     case R_AARCH64_TLS_TPREL64:
-        TRACE_TYPE(RELO, "RELO TLS_TPREL64 *** %16lx <- %16lx - %16lx\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    rela->r_offset);
+        TRACE_TYPE(RELO, "RELO TLS_TPREL64 *** %16llx <- %16llx - %16llx\n",
+                   reloc, (sym_addr + rela->r_addend), rela->r_offset);
         break;
     case R_AARCH64_TLS_DTPREL32:
-        TRACE_TYPE(RELO, "RELO TLS_DTPREL32 *** %16lx <- %16lx - %16lx\n",
-                    reloc,
-                    (sym_addr + rela->r_addend),
-                    rela->r_offset);
+        TRACE_TYPE(RELO, "RELO TLS_DTPREL32 *** %16llx <- %16llx - %16llx\n",
+                   reloc, (sym_addr + rela->r_addend), rela->r_offset);
         break;
 #elif defined(__x86_64__)
     case R_X86_64_JUMP_SLOT:
@@ -1135,14 +1104,14 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
       MARK(rela->r_offset);
       TRACE_TYPE(RELO, "RELO JMP_SLOT %08zx <- %08zx %s", static_cast<size_t>(reloc),
                  static_cast<size_t>(sym_addr + rela->r_addend), sym_name);
-      *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr + rela->r_addend;
+      *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
       break;
     case R_X86_64_GLOB_DAT:
       count_relocation(kRelocAbsolute);
       MARK(rela->r_offset);
       TRACE_TYPE(RELO, "RELO GLOB_DAT %08zx <- %08zx %s", static_cast<size_t>(reloc),
                  static_cast<size_t>(sym_addr + rela->r_addend), sym_name);
-      *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr + rela->r_addend;
+      *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
       break;
     case R_X86_64_RELATIVE:
       count_relocation(kRelocRelative);
@@ -1153,21 +1122,21 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
       }
       TRACE_TYPE(RELO, "RELO RELATIVE %08zx <- +%08zx", static_cast<size_t>(reloc),
                  static_cast<size_t>(si->base));
-      *reinterpret_cast<Elf_Addr*>(reloc) = si->base + rela->r_addend;
+      *reinterpret_cast<ElfW(Addr)*>(reloc) = si->base + rela->r_addend;
       break;
     case R_X86_64_32:
       count_relocation(kRelocRelative);
       MARK(rela->r_offset);
       TRACE_TYPE(RELO, "RELO R_X86_64_32 %08zx <- +%08zx %s", static_cast<size_t>(reloc),
                  static_cast<size_t>(sym_addr), sym_name);
-      *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr + rela->r_addend;
+      *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
       break;
     case R_X86_64_64:
       count_relocation(kRelocRelative);
       MARK(rela->r_offset);
       TRACE_TYPE(RELO, "RELO R_X86_64_64 %08zx <- +%08zx %s", static_cast<size_t>(reloc),
                  static_cast<size_t>(sym_addr), sym_name);
-      *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr + rela->r_addend;
+      *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
       break;
     case R_X86_64_PC32:
       count_relocation(kRelocRelative);
@@ -1175,7 +1144,7 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
       TRACE_TYPE(RELO, "RELO R_X86_64_PC32 %08zx <- +%08zx (%08zx - %08zx) %s",
                  static_cast<size_t>(reloc), static_cast<size_t>(sym_addr - reloc),
                  static_cast<size_t>(sym_addr), static_cast<size_t>(reloc), sym_name);
-      *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr + rela->r_addend - reloc;
+      *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend - reloc;
       break;
 #endif
 
@@ -1187,21 +1156,19 @@ static int soinfo_relocate_a(soinfo* si, Elf_Rela* rela, unsigned count, soinfo*
   return 0;
 }
 #else
-static int soinfo_relocate(soinfo* si, Elf_Rel* rel, unsigned count,
-                           soinfo* needed[])
-{
-    Elf_Sym* symtab = si->symtab;
+static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* needed[]) {
+    ElfW(Sym)* symtab = si->symtab;
     const char* strtab = si->strtab;
-    Elf_Sym* s;
-    Elf_Rel* start = rel;
+    ElfW(Sym)* s;
+    ElfW(Rel)* start = rel;
     soinfo* lsi;
 
     for (size_t idx = 0; idx < count; ++idx, ++rel) {
-        unsigned type = ELF_R_TYPE(rel->r_info);
-        // TODO: don't use unsigned for 'sym'. Use uint32_t or Elf_Addr instead.
-        unsigned sym = ELF_R_SYM(rel->r_info);
-        Elf_Addr reloc = static_cast<Elf_Addr>(rel->r_offset + si->load_bias);
-        Elf_Addr sym_addr = 0;
+        unsigned type = ELFW(R_TYPE)(rel->r_info);
+        // TODO: don't use unsigned for 'sym'. Use uint32_t or ElfW(Addr) instead.
+        unsigned sym = ELFW(R_SYM)(rel->r_info);
+        ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rel->r_offset + si->load_bias);
+        ElfW(Addr) sym_addr = 0;
         char* sym_name = NULL;
 
         DEBUG("Processing '%s' relocation at index %zd", si->name, idx);
@@ -1266,7 +1233,7 @@ static int soinfo_relocate(soinfo* si, Elf_Rel* rel, unsigned count,
                 }
             } else {
                 // We got a definition.
-                sym_addr = static_cast<Elf_Addr>(s->st_value + lsi->load_bias);
+                sym_addr = static_cast<ElfW(Addr)>(s->st_value + lsi->load_bias);
             }
             count_relocation(kRelocSymbol);
         } else {
@@ -1279,26 +1246,26 @@ static int soinfo_relocate(soinfo* si, Elf_Rel* rel, unsigned count,
             count_relocation(kRelocAbsolute);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO JMP_SLOT %08x <- %08x %s", reloc, sym_addr, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
             break;
         case R_ARM_GLOB_DAT:
             count_relocation(kRelocAbsolute);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO GLOB_DAT %08x <- %08x %s", reloc, sym_addr, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
             break;
         case R_ARM_ABS32:
             count_relocation(kRelocAbsolute);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO ABS %08x <- %08x %s", reloc, sym_addr, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) += sym_addr;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
             break;
         case R_ARM_REL32:
             count_relocation(kRelocRelative);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO REL32 %08x <- %08x - %08x %s",
                        reloc, sym_addr, rel->r_offset, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) += sym_addr - rel->r_offset;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr - rel->r_offset;
             break;
         case R_ARM_COPY:
             if ((si->flags & FLAG_EXE) == 0) {
@@ -1320,7 +1287,7 @@ static int soinfo_relocate(soinfo* si, Elf_Rel* rel, unsigned count,
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO %08x <- %d @ %08x %s", reloc, s->st_size, sym_addr, sym_name);
             if (reloc == sym_addr) {
-                Elf_Sym *src = soinfo_do_lookup(NULL, sym_name, &lsi, needed);
+                ElfW(Sym)* src = soinfo_do_lookup(NULL, sym_name, &lsi, needed);
 
                 if (src == NULL) {
                     DL_ERR("%s R_ARM_COPY relocation source cannot be resolved", si->name);
@@ -1347,26 +1314,26 @@ static int soinfo_relocate(soinfo* si, Elf_Rel* rel, unsigned count,
             count_relocation(kRelocAbsolute);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO JMP_SLOT %08x <- %08x %s", reloc, sym_addr, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
             break;
         case R_386_GLOB_DAT:
             count_relocation(kRelocAbsolute);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO GLOB_DAT %08x <- %08x %s", reloc, sym_addr, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) = sym_addr;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
             break;
         case R_386_32:
             count_relocation(kRelocRelative);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO R_386_32 %08x <- +%08x %s", reloc, sym_addr, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) += sym_addr;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
             break;
         case R_386_PC32:
             count_relocation(kRelocRelative);
             MARK(rel->r_offset);
             TRACE_TYPE(RELO, "RELO R_386_PC32 %08x <- +%08x (%08x - %08x) %s",
                        reloc, (sym_addr - reloc), sym_addr, reloc, sym_name);
-            *reinterpret_cast<Elf_Addr*>(reloc) += (sym_addr - reloc);
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr - reloc);
             break;
 #elif defined(__mips__)
         case R_MIPS_REL32:
@@ -1375,9 +1342,9 @@ static int soinfo_relocate(soinfo* si, Elf_Rel* rel, unsigned count,
             TRACE_TYPE(RELO, "RELO REL32 %08x <- %08x %s",
                        reloc, sym_addr, (sym_name) ? sym_name : "*SECTIONHDR*");
             if (s) {
-                *reinterpret_cast<Elf_Addr*>(reloc) += sym_addr;
+                *reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
             } else {
-                *reinterpret_cast<Elf_Addr*>(reloc) += si->base;
+                *reinterpret_cast<ElfW(Addr)*>(reloc) += si->base;
             }
             break;
 #endif
@@ -1395,7 +1362,7 @@ static int soinfo_relocate(soinfo* si, Elf_Rel* rel, unsigned count,
             }
             TRACE_TYPE(RELO, "RELO RELATIVE %p <- +%p",
                        reinterpret_cast<void*>(reloc), reinterpret_cast<void*>(si->base));
-            *reinterpret_cast<Elf_Addr*>(reloc) += si->base;
+            *reinterpret_cast<ElfW(Addr)*>(reloc) += si->base;
             break;
 
         default:
@@ -1416,7 +1383,7 @@ static bool mips_relocate_got(soinfo* si, soinfo* needed[]) {
     unsigned local_gotno = si->mips_local_gotno;
     unsigned gotsym = si->mips_gotsym;
     unsigned symtabno = si->mips_symtabno;
-    Elf_Sym* symtab = si->symtab;
+    ElfW(Sym)* symtab = si->symtab;
 
     /*
      * got[0] is address of lazy resolver function
@@ -1441,11 +1408,11 @@ static bool mips_relocate_got(soinfo* si, soinfo* needed[]) {
     }
 
     /* Now for the global GOT entries */
-    Elf_Sym* sym = symtab + gotsym;
+    ElfW(Sym)* sym = symtab + gotsym;
     got = si->plt_got + local_gotno;
     for (size_t g = gotsym; g < symtabno; g++, sym++, got++) {
         const char* sym_name;
-        Elf_Sym* s;
+        ElfW(Sym)* s;
         soinfo* lsi;
 
         /* This is an undefined reference... try to locate it */
@@ -1536,7 +1503,7 @@ void soinfo::CallConstructors() {
   }
 
   if (dynamic != NULL) {
-    for (Elf_Dyn* d = dynamic; d->d_tag != DT_NULL; ++d) {
+    for (ElfW(Dyn)* d = dynamic; d->d_tag != DT_NULL; ++d) {
       if (d->d_tag == DT_NEEDED) {
         const char* library_name = strtab + d->d_un.d_val;
         TRACE("\"%s\": calling constructors in DT_NEEDED \"%s\"", name, library_name);
@@ -1625,8 +1592,8 @@ static int nullify_closed_stdio() {
 
 static bool soinfo_link_image(soinfo* si) {
     /* "base" might wrap around UINT32_MAX. */
-    Elf_Addr base = si->load_bias;
-    const Elf_Phdr *phdr = si->phdr;
+    ElfW(Addr) base = si->load_bias;
+    const ElfW(Phdr)* phdr = si->phdr;
     int phnum = si->phnum;
     bool relocating_linker = (si->flags & FLAG_LINKER) != 0;
 
@@ -1638,7 +1605,7 @@ static bool soinfo_link_image(soinfo* si) {
 
     /* Extract dynamic section */
     size_t dynamic_count;
-    Elf_Word dynamic_flags;
+    ElfW(Word) dynamic_flags;
     phdr_table_get_dynamic_section(phdr, phnum, base, &si->dynamic,
                                    &dynamic_count, &dynamic_flags);
     if (si->dynamic == NULL) {
@@ -1659,7 +1626,7 @@ static bool soinfo_link_image(soinfo* si) {
 
     // Extract useful information from dynamic section.
     uint32_t needed_count = 0;
-    for (Elf_Dyn* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
+    for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
         DEBUG("d = %p, d[0](tag) = %p d[1](val) = %p",
               d, reinterpret_cast<void*>(d->d_tag), reinterpret_cast<void*>(d->d_un.d_val));
         switch (d->d_tag) {
@@ -1673,7 +1640,7 @@ static bool soinfo_link_image(soinfo* si) {
             si->strtab = (const char *) (base + d->d_un.d_ptr);
             break;
         case DT_SYMTAB:
-            si->symtab = (Elf_Sym *) (base + d->d_un.d_ptr);
+            si->symtab = (ElfW(Sym)*) (base + d->d_un.d_ptr);
             break;
 #if !defined(__LP64__)
         case DT_PLTREL:
@@ -1685,16 +1652,16 @@ static bool soinfo_link_image(soinfo* si) {
 #endif
         case DT_JMPREL:
 #if defined(USE_RELA)
-            si->plt_rela = (Elf_Rela*) (base + d->d_un.d_ptr);
+            si->plt_rela = (ElfW(Rela)*) (base + d->d_un.d_ptr);
 #else
-            si->plt_rel = (Elf_Rel*) (base + d->d_un.d_ptr);
+            si->plt_rel = (ElfW(Rel)*) (base + d->d_un.d_ptr);
 #endif
             break;
         case DT_PLTRELSZ:
 #if defined(USE_RELA)
-            si->plt_rela_count = d->d_un.d_val / sizeof(Elf_Rela);
+            si->plt_rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
 #else
-            si->plt_rel_count = d->d_un.d_val / sizeof(Elf_Rel);
+            si->plt_rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
 #endif
             break;
 #if !defined(__LP64__)
@@ -1712,10 +1679,10 @@ static bool soinfo_link_image(soinfo* si) {
             break;
 #if defined(USE_RELA)
          case DT_RELA:
-            si->rela = (Elf_Rela*) (base + d->d_un.d_ptr);
+            si->rela = (ElfW(Rela)*) (base + d->d_un.d_ptr);
             break;
          case DT_RELASZ:
-            si->rela_count = d->d_un.d_val / sizeof(Elf_Rela);
+            si->rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
             break;
         case DT_REL:
             DL_ERR("unsupported DT_REL in \"%s\"", si->name);
@@ -1725,10 +1692,10 @@ static bool soinfo_link_image(soinfo* si) {
             return false;
 #else
         case DT_REL:
-            si->rel = (Elf_Rel*) (base + d->d_un.d_ptr);
+            si->rel = (ElfW(Rel)*) (base + d->d_un.d_ptr);
             break;
         case DT_RELSZ:
-            si->rel_count = d->d_un.d_val / sizeof(Elf_Rel);
+            si->rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
             break;
          case DT_RELA:
             DL_ERR("unsupported DT_RELA in \"%s\"", si->name);
@@ -1747,21 +1714,21 @@ static bool soinfo_link_image(soinfo* si) {
             DEBUG("%s constructors (DT_INIT_ARRAY) found at %p", si->name, si->init_array);
             break;
         case DT_INIT_ARRAYSZ:
-            si->init_array_count = ((unsigned)d->d_un.d_val) / sizeof(Elf_Addr);
+            si->init_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
             break;
         case DT_FINI_ARRAY:
             si->fini_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
             DEBUG("%s destructors (DT_FINI_ARRAY) found at %p", si->name, si->fini_array);
             break;
         case DT_FINI_ARRAYSZ:
-            si->fini_array_count = ((unsigned)d->d_un.d_val) / sizeof(Elf_Addr);
+            si->fini_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
             break;
         case DT_PREINIT_ARRAY:
             si->preinit_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
             DEBUG("%s constructors (DT_PREINIT_ARRAY) found at %p", si->name, si->preinit_array);
             break;
         case DT_PREINIT_ARRAYSZ:
-            si->preinit_array_count = ((unsigned)d->d_un.d_val) / sizeof(Elf_Addr);
+            si->preinit_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
             break;
         case DT_TEXTREL:
 #if defined(__LP64__)
@@ -1868,7 +1835,7 @@ static bool soinfo_link_image(soinfo* si) {
     soinfo** needed = (soinfo**) alloca((1 + needed_count) * sizeof(soinfo*));
     soinfo** pneeded = needed;
 
-    for (Elf_Dyn* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
+    for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
         if (d->d_tag == DT_NEEDED) {
             const char* library_name = si->strtab + d->d_un.d_val;
             DEBUG("%s needs %s", si->name, library_name);
@@ -1964,21 +1931,21 @@ static bool soinfo_link_image(soinfo* si) {
  */
 static void add_vdso(KernelArgumentBlock& args UNUSED) {
 #if defined(AT_SYSINFO_EHDR)
-    Elf_Ehdr* ehdr_vdso = reinterpret_cast<Elf_Ehdr*>(args.getauxval(AT_SYSINFO_EHDR));
-    if (ehdr_vdso == NULL) {
-        return;
-    }
+  ElfW(Ehdr)* ehdr_vdso = reinterpret_cast<ElfW(Ehdr)*>(args.getauxval(AT_SYSINFO_EHDR));
+  if (ehdr_vdso == NULL) {
+    return;
+  }
 
-    soinfo* si = soinfo_alloc("[vdso]");
+  soinfo* si = soinfo_alloc("[vdso]");
 
-    si->phdr = reinterpret_cast<Elf_Phdr*>(reinterpret_cast<char*>(ehdr_vdso) + ehdr_vdso->e_phoff);
-    si->phnum = ehdr_vdso->e_phnum;
-    si->base = reinterpret_cast<Elf_Addr>(ehdr_vdso);
-    si->size = phdr_table_get_load_size(si->phdr, si->phnum);
-    si->flags = 0;
-    si->load_bias = get_elf_exec_load_bias(ehdr_vdso);
+  si->phdr = reinterpret_cast<ElfW(Phdr)*>(reinterpret_cast<char*>(ehdr_vdso) + ehdr_vdso->e_phoff);
+  si->phnum = ehdr_vdso->e_phnum;
+  si->base = reinterpret_cast<ElfW(Addr)>(ehdr_vdso);
+  si->size = phdr_table_get_load_size(si->phdr, si->phnum);
+  si->flags = 0;
+  si->load_bias = get_elf_exec_load_bias(ehdr_vdso);
 
-    soinfo_link_image(si);
+  soinfo_link_image(si);
 #endif
 }
 
@@ -1987,7 +1954,7 @@ static void add_vdso(KernelArgumentBlock& args UNUSED) {
  * fixed it's own GOT. It is safe to make references to externs
  * and other non-local data at this point.
  */
-static Elf_Addr __linker_init_post_relocation(KernelArgumentBlock& args, Elf_Addr linker_base) {
+static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(Addr) linker_base) {
     /* NOTE: we store the args pointer on a special location
      *       of the temporary TLS area in order to pass it to
      *       the C Library's runtime initializer.
@@ -2071,15 +2038,15 @@ static Elf_Addr __linker_init_post_relocation(KernelArgumentBlock& args, Elf_Add
          *   warning: .dynamic section for "/system/bin/linker" is not at the
          *   expected address (wrong library or version mismatch?)
          */
-        Elf_Ehdr *elf_hdr = (Elf_Ehdr *) linker_base;
-        Elf_Phdr *phdr = (Elf_Phdr*)((unsigned char*) linker_base + elf_hdr->e_phoff);
+        ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(linker_base);
+        ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr)*>((unsigned char*) linker_base + elf_hdr->e_phoff);
         phdr_table_get_dynamic_section(phdr, elf_hdr->e_phnum, linker_base,
                                        &linker_soinfo.dynamic, NULL, NULL);
         insert_soinfo_into_debug_map(&linker_soinfo);
     }
 
     // Extract information passed from the kernel.
-    si->phdr = reinterpret_cast<Elf_Phdr*>(args.getauxval(AT_PHDR));
+    si->phdr = reinterpret_cast<ElfW(Phdr)*>(args.getauxval(AT_PHDR));
     si->phnum = args.getauxval(AT_PHNUM);
     si->entry = args.getauxval(AT_ENTRY);
 
@@ -2092,8 +2059,8 @@ static Elf_Addr __linker_init_post_relocation(KernelArgumentBlock& args, Elf_Add
     si->load_bias = 0;
     for (size_t i = 0; i < si->phnum; ++i) {
       if (si->phdr[i].p_type == PT_PHDR) {
-        si->load_bias = reinterpret_cast<Elf_Addr>(si->phdr) - si->phdr[i].p_vaddr;
-        si->base = reinterpret_cast<Elf_Addr>(si->phdr) - si->phdr[i].p_offset;
+        si->load_bias = reinterpret_cast<ElfW(Addr)>(si->phdr) - si->phdr[i].p_vaddr;
+        si->base = reinterpret_cast<ElfW(Addr)>(si->phdr) - si->phdr[i].p_offset;
         break;
       }
     }
@@ -2183,14 +2150,14 @@ static Elf_Addr __linker_init_post_relocation(KernelArgumentBlock& args, Elf_Add
  *    load bias, i.e. add the value of any p_vaddr in the file to get
  *    the corresponding address in memory.
  */
-static Elf_Addr get_elf_exec_load_bias(const Elf_Ehdr* elf) {
-  Elf_Addr offset = elf->e_phoff;
-  const Elf_Phdr* phdr_table = (const Elf_Phdr*)((char*)elf + offset);
-  const Elf_Phdr* phdr_end = phdr_table + elf->e_phnum;
+static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf) {
+  ElfW(Addr) offset = elf->e_phoff;
+  const ElfW(Phdr)* phdr_table = reinterpret_cast<const ElfW(Phdr)*>((char*)elf + offset);
+  const ElfW(Phdr)* phdr_end = phdr_table + elf->e_phnum;
 
-  for (const Elf_Phdr* phdr = phdr_table; phdr < phdr_end; phdr++) {
+  for (const ElfW(Phdr)* phdr = phdr_table; phdr < phdr_end; phdr++) {
     if (phdr->p_type == PT_LOAD) {
-      return reinterpret_cast<Elf_Addr>(elf) + phdr->p_offset - phdr->p_vaddr;
+      return reinterpret_cast<ElfW(Addr)>(elf) + phdr->p_offset - phdr->p_vaddr;
     }
   }
   return 0;
@@ -2205,12 +2172,12 @@ static Elf_Addr get_elf_exec_load_bias(const Elf_Ehdr* elf) {
  * relocations, any attempt to reference an extern variable, extern
  * function, or other GOT reference will generate a segfault.
  */
-extern "C" Elf_Addr __linker_init(void* raw_args) {
+extern "C" ElfW(Addr) __linker_init(void* raw_args) {
   KernelArgumentBlock args(raw_args);
 
-  Elf_Addr linker_addr = args.getauxval(AT_BASE);
-  Elf_Ehdr* elf_hdr = reinterpret_cast<Elf_Ehdr*>(linker_addr);
-  Elf_Phdr* phdr = (Elf_Phdr*)((unsigned char*) linker_addr + elf_hdr->e_phoff);
+  ElfW(Addr) linker_addr = args.getauxval(AT_BASE);
+  ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(linker_addr);
+  ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr)*>((unsigned char*) linker_addr + elf_hdr->e_phoff);
 
   soinfo linker_so;
   memset(&linker_so, 0, sizeof(soinfo));
@@ -2239,7 +2206,7 @@ extern "C" Elf_Addr __linker_init(void* raw_args) {
   // We have successfully fixed our own relocations. It's safe to run
   // the main part of the linker now.
   args.abort_message_ptr = &gAbortMessage;
-  Elf_Addr start_address = __linker_init_post_relocation(args, linker_addr);
+  ElfW(Addr) start_address = __linker_init_post_relocation(args, linker_addr);
 
   set_soinfo_pool_protection(PROT_READ);
 
diff --git a/linker/linker.h b/linker/linker.h
index 654ee5f..bb35ffc 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -50,6 +50,11 @@
       __libc_format_fd(2, "\n"); \
     } while (false)
 
+#if defined(__LP64__)
+#define ELFW(what) ELF64_ ## what
+#else
+#define ELFW(what) ELF32_ ## what
+#endif
 
 // Returns the address of the page containing address 'x'.
 #define PAGE_START(x)  ((x) & PAGE_MASK)
@@ -77,17 +82,17 @@ typedef void (*linker_function_t)();
 struct soinfo {
  public:
   char name[SOINFO_NAME_LEN];
-  const Elf_Phdr* phdr;
+  const ElfW(Phdr)* phdr;
   size_t phnum;
-  Elf_Addr entry;
-  Elf_Addr base;
+  ElfW(Addr) entry;
+  ElfW(Addr) base;
   size_t size;
 
 #ifndef __LP64__
   uint32_t unused1;  // DO NOT USE, maintained for compatibility.
 #endif
 
-  Elf_Dyn* dynamic;
+  ElfW(Dyn)* dynamic;
 
 #ifndef __LP64__
   uint32_t unused2; // DO NOT USE, maintained for compatibility
@@ -98,7 +103,7 @@ struct soinfo {
   unsigned flags;
 
   const char* strtab;
-  Elf_Sym* symtab;
+  ElfW(Sym)* symtab;
 
   size_t nbucket;
   size_t nchain;
@@ -112,16 +117,16 @@ struct soinfo {
 #endif
 
 #if defined(USE_RELA)
-  Elf_Rela* plt_rela;
+  ElfW(Rela)* plt_rela;
   size_t plt_rela_count;
 
-  Elf_Rela* rela;
+  ElfW(Rela)* rela;
   size_t rela_count;
 #else
-  Elf_Rel* plt_rel;
+  ElfW(Rel)* plt_rel;
   size_t plt_rel_count;
 
-  Elf_Rel* rel;
+  ElfW(Rel)* rel;
   size_t rel_count;
 #endif
 
@@ -153,7 +158,7 @@ struct soinfo {
 
   // When you read a virtual address from the ELF file, add this
   // value to get the corresponding address in the process' address space.
-  Elf_Addr load_bias;
+  ElfW(Addr) load_bias;
 
 #if !defined(__LP64__)
   bool has_text_relocations;
@@ -176,11 +181,11 @@ void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path);
 soinfo* do_dlopen(const char* name, int flags);
 int do_dlclose(soinfo* si);
 
-Elf_Sym* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start);
+ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start);
 soinfo* find_containing_library(const void* addr);
 
-Elf_Sym* dladdr_find_symbol(soinfo* si, const void* addr);
-Elf_Sym* dlsym_handle_lookup(soinfo* si, const char* name);
+ElfW(Sym)* dladdr_find_symbol(soinfo* si, const void* addr);
+ElfW(Sym)* dlsym_handle_lookup(soinfo* si, const char* name);
 
 void debuggerd_init();
 extern "C" abort_msg_t* gAbortMessage;
diff --git a/linker/linker_phdr.cpp b/linker/linker_phdr.cpp
index 3101511..391e4cf 100644
--- a/linker/linker_phdr.cpp
+++ b/linker/linker_phdr.cpp
@@ -50,7 +50,7 @@
     p_vaddr   -> segment's virtual address
     p_flags   -> segment flags (e.g. readable, writable, executable)
 
-  We will ignore the p_paddr and p_align fields of Elf_Phdr for now.
+  We will ignore the p_paddr and p_align fields of ElfW(Phdr) for now.
 
   The loadable segments can be seen as a list of [p_vaddr ... p_vaddr+p_memsz)
   ranges of virtual addresses. A few rules apply:
@@ -217,14 +217,14 @@ bool ElfReader::ReadProgramHeader() {
 
   // Like the kernel, we only accept program header tables that
   // are smaller than 64KiB.
-  if (phdr_num_ < 1 || phdr_num_ > 65536/sizeof(Elf_Phdr)) {
+  if (phdr_num_ < 1 || phdr_num_ > 65536/sizeof(ElfW(Phdr))) {
     DL_ERR("\"%s\" has invalid e_phnum: %zd", name_, phdr_num_);
     return false;
   }
 
-  Elf_Addr page_min = PAGE_START(header_.e_phoff);
-  Elf_Addr page_max = PAGE_END(header_.e_phoff + (phdr_num_ * sizeof(Elf_Phdr)));
-  Elf_Addr page_offset = PAGE_OFFSET(header_.e_phoff);
+  ElfW(Addr) page_min = PAGE_START(header_.e_phoff);
+  ElfW(Addr) page_max = PAGE_END(header_.e_phoff + (phdr_num_ * sizeof(ElfW(Phdr))));
+  ElfW(Addr) page_offset = PAGE_OFFSET(header_.e_phoff);
 
   phdr_size_ = page_max - page_min;
 
@@ -235,7 +235,7 @@ bool ElfReader::ReadProgramHeader() {
   }
 
   phdr_mmap_ = mmap_result;
-  phdr_table_ = reinterpret_cast<Elf_Phdr*>(reinterpret_cast<char*>(mmap_result) + page_offset);
+  phdr_table_ = reinterpret_cast<ElfW(Phdr)*>(reinterpret_cast<char*>(mmap_result) + page_offset);
   return true;
 }
 
@@ -249,50 +249,50 @@ bool ElfReader::ReadProgramHeader() {
  * set to the minimum and maximum addresses of pages to be reserved,
  * or 0 if there is nothing to load.
  */
-size_t phdr_table_get_load_size(const Elf_Phdr* phdr_table, size_t phdr_count,
-                                Elf_Addr* out_min_vaddr,
-                                Elf_Addr* out_max_vaddr) {
-    Elf_Addr min_vaddr = UINTPTR_MAX;
-    Elf_Addr max_vaddr = 0;
-
-    bool found_pt_load = false;
-    for (size_t i = 0; i < phdr_count; ++i) {
-        const Elf_Phdr* phdr = &phdr_table[i];
-
-        if (phdr->p_type != PT_LOAD) {
-            continue;
-        }
-        found_pt_load = true;
-
-        if (phdr->p_vaddr < min_vaddr) {
-            min_vaddr = phdr->p_vaddr;
-        }
-
-        if (phdr->p_vaddr + phdr->p_memsz > max_vaddr) {
-            max_vaddr = phdr->p_vaddr + phdr->p_memsz;
-        }
-    }
-    if (!found_pt_load) {
-        min_vaddr = 0;
-    }
+size_t phdr_table_get_load_size(const ElfW(Phdr)* phdr_table, size_t phdr_count,
+                                ElfW(Addr)* out_min_vaddr,
+                                ElfW(Addr)* out_max_vaddr) {
+  ElfW(Addr) min_vaddr = UINTPTR_MAX;
+  ElfW(Addr) max_vaddr = 0;
 
-    min_vaddr = PAGE_START(min_vaddr);
-    max_vaddr = PAGE_END(max_vaddr);
+  bool found_pt_load = false;
+  for (size_t i = 0; i < phdr_count; ++i) {
+    const ElfW(Phdr)* phdr = &phdr_table[i];
 
-    if (out_min_vaddr != NULL) {
-        *out_min_vaddr = min_vaddr;
+    if (phdr->p_type != PT_LOAD) {
+      continue;
     }
-    if (out_max_vaddr != NULL) {
-        *out_max_vaddr = max_vaddr;
+    found_pt_load = true;
+
+    if (phdr->p_vaddr < min_vaddr) {
+      min_vaddr = phdr->p_vaddr;
     }
-    return max_vaddr - min_vaddr;
+
+    if (phdr->p_vaddr + phdr->p_memsz > max_vaddr) {
+      max_vaddr = phdr->p_vaddr + phdr->p_memsz;
+    }
+  }
+  if (!found_pt_load) {
+    min_vaddr = 0;
+  }
+
+  min_vaddr = PAGE_START(min_vaddr);
+  max_vaddr = PAGE_END(max_vaddr);
+
+  if (out_min_vaddr != NULL) {
+    *out_min_vaddr = min_vaddr;
+  }
+  if (out_max_vaddr != NULL) {
+    *out_max_vaddr = max_vaddr;
+  }
+  return max_vaddr - min_vaddr;
 }
 
 // Reserve a virtual address range big enough to hold all loadable
 // segments of a program header table. This is done by creating a
 // private anonymous mmap() with PROT_NONE.
 bool ElfReader::ReserveAddressSpace() {
-  Elf_Addr min_vaddr;
+  ElfW(Addr) min_vaddr;
   load_size_ = phdr_table_get_load_size(phdr_table_, phdr_num_, &min_vaddr);
   if (load_size_ == 0) {
     DL_ERR("\"%s\" has no loadable segments", name_);
@@ -314,27 +314,27 @@ bool ElfReader::ReserveAddressSpace() {
 
 bool ElfReader::LoadSegments() {
   for (size_t i = 0; i < phdr_num_; ++i) {
-    const Elf_Phdr* phdr = &phdr_table_[i];
+    const ElfW(Phdr)* phdr = &phdr_table_[i];
 
     if (phdr->p_type != PT_LOAD) {
       continue;
     }
 
     // Segment addresses in memory.
-    Elf_Addr seg_start = phdr->p_vaddr + load_bias_;
-    Elf_Addr seg_end   = seg_start + phdr->p_memsz;
+    ElfW(Addr) seg_start = phdr->p_vaddr + load_bias_;
+    ElfW(Addr) seg_end   = seg_start + phdr->p_memsz;
 
-    Elf_Addr seg_page_start = PAGE_START(seg_start);
-    Elf_Addr seg_page_end   = PAGE_END(seg_end);
+    ElfW(Addr) seg_page_start = PAGE_START(seg_start);
+    ElfW(Addr) seg_page_end   = PAGE_END(seg_end);
 
-    Elf_Addr seg_file_end   = seg_start + phdr->p_filesz;
+    ElfW(Addr) seg_file_end   = seg_start + phdr->p_filesz;
 
     // File offsets.
-    Elf_Addr file_start = phdr->p_offset;
-    Elf_Addr file_end   = file_start + phdr->p_filesz;
+    ElfW(Addr) file_start = phdr->p_offset;
+    ElfW(Addr) file_end   = file_start + phdr->p_filesz;
 
-    Elf_Addr file_page_start = PAGE_START(file_start);
-    Elf_Addr file_length = file_end - file_page_start;
+    ElfW(Addr) file_page_start = PAGE_START(file_start);
+    ElfW(Addr) file_length = file_end - file_page_start;
 
     if (file_length != 0) {
       void* seg_addr = mmap((void*)seg_page_start,
@@ -381,26 +381,27 @@ bool ElfReader::LoadSegments() {
  * with optional extra flags (i.e. really PROT_WRITE). Used by
  * phdr_table_protect_segments and phdr_table_unprotect_segments.
  */
-static int _phdr_table_set_load_prot(const Elf_Phdr* phdr_table, size_t phdr_count,
-                                     Elf_Addr load_bias, int extra_prot_flags) {
-    const Elf_Phdr* phdr = phdr_table;
-    const Elf_Phdr* phdr_limit = phdr + phdr_count;
-
-    for (; phdr < phdr_limit; phdr++) {
-        if (phdr->p_type != PT_LOAD || (phdr->p_flags & PF_W) != 0)
-            continue;
-
-        Elf_Addr seg_page_start = PAGE_START(phdr->p_vaddr) + load_bias;
-        Elf_Addr seg_page_end   = PAGE_END(phdr->p_vaddr + phdr->p_memsz) + load_bias;
-
-        int ret = mprotect((void*)seg_page_start,
-                           seg_page_end - seg_page_start,
-                           PFLAGS_TO_PROT(phdr->p_flags) | extra_prot_flags);
-        if (ret < 0) {
-            return -1;
-        }
+static int _phdr_table_set_load_prot(const ElfW(Phdr)* phdr_table, size_t phdr_count,
+                                     ElfW(Addr) load_bias, int extra_prot_flags) {
+  const ElfW(Phdr)* phdr = phdr_table;
+  const ElfW(Phdr)* phdr_limit = phdr + phdr_count;
+
+  for (; phdr < phdr_limit; phdr++) {
+    if (phdr->p_type != PT_LOAD || (phdr->p_flags & PF_W) != 0) {
+      continue;
     }
-    return 0;
+
+    ElfW(Addr) seg_page_start = PAGE_START(phdr->p_vaddr) + load_bias;
+    ElfW(Addr) seg_page_end   = PAGE_END(phdr->p_vaddr + phdr->p_memsz) + load_bias;
+
+    int ret = mprotect((void*)seg_page_start,
+                       seg_page_end - seg_page_start,
+                       PFLAGS_TO_PROT(phdr->p_flags) | extra_prot_flags);
+    if (ret < 0) {
+      return -1;
+    }
+  }
+  return 0;
 }
 
 /* Restore the original protection modes for all loadable segments.
@@ -414,8 +415,8 @@ static int _phdr_table_set_load_prot(const Elf_Phdr* phdr_table, size_t phdr_cou
  * Return:
  *   0 on error, -1 on failure (error code in errno).
  */
-int phdr_table_protect_segments(const Elf_Phdr* phdr_table, size_t phdr_count, Elf_Addr load_bias) {
-    return _phdr_table_set_load_prot(phdr_table, phdr_count, load_bias, 0);
+int phdr_table_protect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias) {
+  return _phdr_table_set_load_prot(phdr_table, phdr_count, load_bias, 0);
 }
 
 /* Change the protection of all loaded segments in memory to writable.
@@ -434,50 +435,50 @@ int phdr_table_protect_segments(const Elf_Phdr* phdr_table, size_t phdr_count, E
  * Return:
  *   0 on error, -1 on failure (error code in errno).
  */
-int phdr_table_unprotect_segments(const Elf_Phdr* phdr_table, size_t phdr_count, Elf_Addr load_bias) {
-    return _phdr_table_set_load_prot(phdr_table, phdr_count, load_bias, PROT_WRITE);
+int phdr_table_unprotect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias) {
+  return _phdr_table_set_load_prot(phdr_table, phdr_count, load_bias, PROT_WRITE);
 }
 
 /* Used internally by phdr_table_protect_gnu_relro and
  * phdr_table_unprotect_gnu_relro.
  */
-static int _phdr_table_set_gnu_relro_prot(const Elf_Phdr* phdr_table, size_t phdr_count,
-                                          Elf_Addr load_bias, int prot_flags) {
-    const Elf_Phdr* phdr = phdr_table;
-    const Elf_Phdr* phdr_limit = phdr + phdr_count;
-
-    for (phdr = phdr_table; phdr < phdr_limit; phdr++) {
-        if (phdr->p_type != PT_GNU_RELRO)
-            continue;
-
-        /* Tricky: what happens when the relro segment does not start
-         * or end at page boundaries?. We're going to be over-protective
-         * here and put every page touched by the segment as read-only.
-         *
-         * This seems to match Ian Lance Taylor's description of the
-         * feature at http://www.airs.com/blog/archives/189.
-         *
-         * Extract:
-         *    Note that the current dynamic linker code will only work
-         *    correctly if the PT_GNU_RELRO segment starts on a page
-         *    boundary. This is because the dynamic linker rounds the
-         *    p_vaddr field down to the previous page boundary. If
-         *    there is anything on the page which should not be read-only,
-         *    the program is likely to fail at runtime. So in effect the
-         *    linker must only emit a PT_GNU_RELRO segment if it ensures
-         *    that it starts on a page boundary.
-         */
-        Elf_Addr seg_page_start = PAGE_START(phdr->p_vaddr) + load_bias;
-        Elf_Addr seg_page_end   = PAGE_END(phdr->p_vaddr + phdr->p_memsz) + load_bias;
-
-        int ret = mprotect((void*)seg_page_start,
-                           seg_page_end - seg_page_start,
-                           prot_flags);
-        if (ret < 0) {
-            return -1;
-        }
+static int _phdr_table_set_gnu_relro_prot(const ElfW(Phdr)* phdr_table, size_t phdr_count,
+                                          ElfW(Addr) load_bias, int prot_flags) {
+  const ElfW(Phdr)* phdr = phdr_table;
+  const ElfW(Phdr)* phdr_limit = phdr + phdr_count;
+
+  for (phdr = phdr_table; phdr < phdr_limit; phdr++) {
+    if (phdr->p_type != PT_GNU_RELRO) {
+      continue;
     }
-    return 0;
+
+    // Tricky: what happens when the relro segment does not start
+    // or end at page boundaries? We're going to be over-protective
+    // here and put every page touched by the segment as read-only.
+
+    // This seems to match Ian Lance Taylor's description of the
+    // feature at http://www.airs.com/blog/archives/189.
+
+    //    Extract:
+    //       Note that the current dynamic linker code will only work
+    //       correctly if the PT_GNU_RELRO segment starts on a page
+    //       boundary. This is because the dynamic linker rounds the
+    //       p_vaddr field down to the previous page boundary. If
+    //       there is anything on the page which should not be read-only,
+    //       the program is likely to fail at runtime. So in effect the
+    //       linker must only emit a PT_GNU_RELRO segment if it ensures
+    //       that it starts on a page boundary.
+    ElfW(Addr) seg_page_start = PAGE_START(phdr->p_vaddr) + load_bias;
+    ElfW(Addr) seg_page_end   = PAGE_END(phdr->p_vaddr + phdr->p_memsz) + load_bias;
+
+    int ret = mprotect((void*)seg_page_start,
+                       seg_page_end - seg_page_start,
+                       prot_flags);
+    if (ret < 0) {
+      return -1;
+    }
+  }
+  return 0;
 }
 
 /* Apply GNU relro protection if specified by the program header. This will
@@ -496,8 +497,8 @@ static int _phdr_table_set_gnu_relro_prot(const Elf_Phdr* phdr_table, size_t phd
  * Return:
  *   0 on error, -1 on failure (error code in errno).
  */
-int phdr_table_protect_gnu_relro(const Elf_Phdr* phdr_table, size_t phdr_count, Elf_Addr load_bias) {
-    return _phdr_table_set_gnu_relro_prot(phdr_table, phdr_count, load_bias, PROT_READ);
+int phdr_table_protect_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias) {
+  return _phdr_table_set_gnu_relro_prot(phdr_table, phdr_count, load_bias, PROT_READ);
 }
 
 #if defined(__arm__)
@@ -519,23 +520,24 @@ int phdr_table_protect_gnu_relro(const Elf_Phdr* phdr_table, size_t phdr_count,
  * Return:
  *   0 on error, -1 on failure (_no_ error code in errno)
  */
-int phdr_table_get_arm_exidx(const Elf_Phdr* phdr_table, size_t phdr_count,
-                             Elf_Addr load_bias,
-                             Elf_Addr** arm_exidx, unsigned* arm_exidx_count) {
-    const Elf_Phdr* phdr = phdr_table;
-    const Elf_Phdr* phdr_limit = phdr + phdr_count;
-
-    for (phdr = phdr_table; phdr < phdr_limit; phdr++) {
-        if (phdr->p_type != PT_ARM_EXIDX)
-            continue;
-
-        *arm_exidx = (Elf_Addr*)(load_bias + phdr->p_vaddr);
-        *arm_exidx_count = (unsigned)(phdr->p_memsz / 8);
-        return 0;
+int phdr_table_get_arm_exidx(const ElfW(Phdr)* phdr_table, size_t phdr_count,
+                             ElfW(Addr) load_bias,
+                             ElfW(Addr)** arm_exidx, unsigned* arm_exidx_count) {
+  const ElfW(Phdr)* phdr = phdr_table;
+  const ElfW(Phdr)* phdr_limit = phdr + phdr_count;
+
+  for (phdr = phdr_table; phdr < phdr_limit; phdr++) {
+    if (phdr->p_type != PT_ARM_EXIDX) {
+      continue;
     }
-    *arm_exidx = NULL;
-    *arm_exidx_count = 0;
-    return -1;
+
+    *arm_exidx = reinterpret_cast<ElfW(Addr)*>(load_bias + phdr->p_vaddr);
+    *arm_exidx_count = (unsigned)(phdr->p_memsz / 8);
+    return 0;
+  }
+  *arm_exidx = NULL;
+  *arm_exidx_count = 0;
+  return -1;
 }
 #endif
 
@@ -553,40 +555,40 @@ int phdr_table_get_arm_exidx(const Elf_Phdr* phdr_table, size_t phdr_count,
  * Return:
  *   void
  */
-void phdr_table_get_dynamic_section(const Elf_Phdr* phdr_table, size_t phdr_count,
-                                    Elf_Addr load_bias,
-                                    Elf_Dyn** dynamic, size_t* dynamic_count, Elf_Word* dynamic_flags) {
-    const Elf_Phdr* phdr = phdr_table;
-    const Elf_Phdr* phdr_limit = phdr + phdr_count;
-
-    for (phdr = phdr_table; phdr < phdr_limit; phdr++) {
-        if (phdr->p_type != PT_DYNAMIC) {
-            continue;
-        }
-
-        *dynamic = reinterpret_cast<Elf_Dyn*>(load_bias + phdr->p_vaddr);
-        if (dynamic_count) {
-            *dynamic_count = (unsigned)(phdr->p_memsz / 8);
-        }
-        if (dynamic_flags) {
-            *dynamic_flags = phdr->p_flags;
-        }
-        return;
+void phdr_table_get_dynamic_section(const ElfW(Phdr)* phdr_table, size_t phdr_count,
+                                    ElfW(Addr) load_bias,
+                                    ElfW(Dyn)** dynamic, size_t* dynamic_count, ElfW(Word)* dynamic_flags) {
+  const ElfW(Phdr)* phdr = phdr_table;
+  const ElfW(Phdr)* phdr_limit = phdr + phdr_count;
+
+  for (phdr = phdr_table; phdr < phdr_limit; phdr++) {
+    if (phdr->p_type != PT_DYNAMIC) {
+      continue;
     }
-    *dynamic = NULL;
+
+    *dynamic = reinterpret_cast<ElfW(Dyn)*>(load_bias + phdr->p_vaddr);
     if (dynamic_count) {
-        *dynamic_count = 0;
+      *dynamic_count = (unsigned)(phdr->p_memsz / 8);
+    }
+    if (dynamic_flags) {
+      *dynamic_flags = phdr->p_flags;
     }
+    return;
+  }
+  *dynamic = NULL;
+  if (dynamic_count) {
+    *dynamic_count = 0;
+  }
 }
 
 // Returns the address of the program header table as it appears in the loaded
 // segments in memory. This is in contrast with 'phdr_table_' which
 // is temporary and will be released before the library is relocated.
 bool ElfReader::FindPhdr() {
-  const Elf_Phdr* phdr_limit = phdr_table_ + phdr_num_;
+  const ElfW(Phdr)* phdr_limit = phdr_table_ + phdr_num_;
 
   // If there is a PT_PHDR, use it directly.
-  for (const Elf_Phdr* phdr = phdr_table_; phdr < phdr_limit; ++phdr) {
+  for (const ElfW(Phdr)* phdr = phdr_table_; phdr < phdr_limit; ++phdr) {
     if (phdr->p_type == PT_PHDR) {
       return CheckPhdr(load_bias_ + phdr->p_vaddr);
     }
@@ -595,13 +597,13 @@ bool ElfReader::FindPhdr() {
   // Otherwise, check the first loadable segment. If its file offset
   // is 0, it starts with the ELF header, and we can trivially find the
   // loaded program header from it.
-  for (const Elf_Phdr* phdr = phdr_table_; phdr < phdr_limit; ++phdr) {
+  for (const ElfW(Phdr)* phdr = phdr_table_; phdr < phdr_limit; ++phdr) {
     if (phdr->p_type == PT_LOAD) {
       if (phdr->p_offset == 0) {
-        Elf_Addr  elf_addr = load_bias_ + phdr->p_vaddr;
-        const Elf_Ehdr* ehdr = (const Elf_Ehdr*)(void*)elf_addr;
-        Elf_Addr  offset = ehdr->e_phoff;
-        return CheckPhdr((Elf_Addr)ehdr + offset);
+        ElfW(Addr)  elf_addr = load_bias_ + phdr->p_vaddr;
+        const ElfW(Ehdr)* ehdr = (const ElfW(Ehdr)*)(void*)elf_addr;
+        ElfW(Addr)  offset = ehdr->e_phoff;
+        return CheckPhdr((ElfW(Addr))ehdr + offset);
       }
       break;
     }
@@ -614,17 +616,17 @@ bool ElfReader::FindPhdr() {
 // Ensures that our program header is actually within a loadable
 // segment. This should help catch badly-formed ELF files that
 // would cause the linker to crash later when trying to access it.
-bool ElfReader::CheckPhdr(Elf_Addr loaded) {
-  const Elf_Phdr* phdr_limit = phdr_table_ + phdr_num_;
-  Elf_Addr loaded_end = loaded + (phdr_num_ * sizeof(Elf_Phdr));
-  for (Elf_Phdr* phdr = phdr_table_; phdr < phdr_limit; ++phdr) {
+bool ElfReader::CheckPhdr(ElfW(Addr) loaded) {
+  const ElfW(Phdr)* phdr_limit = phdr_table_ + phdr_num_;
+  ElfW(Addr) loaded_end = loaded + (phdr_num_ * sizeof(ElfW(Phdr)));
+  for (ElfW(Phdr)* phdr = phdr_table_; phdr < phdr_limit; ++phdr) {
     if (phdr->p_type != PT_LOAD) {
       continue;
     }
-    Elf_Addr seg_start = phdr->p_vaddr + load_bias_;
-    Elf_Addr seg_end = phdr->p_filesz + seg_start;
+    ElfW(Addr) seg_start = phdr->p_vaddr + load_bias_;
+    ElfW(Addr) seg_end = phdr->p_filesz + seg_start;
     if (seg_start <= loaded && loaded_end <= seg_end) {
-      loaded_phdr_ = reinterpret_cast<const Elf_Phdr*>(loaded);
+      loaded_phdr_ = reinterpret_cast<const ElfW(Phdr)*>(loaded);
       return true;
     }
   }
diff --git a/linker/linker_phdr.h b/linker/linker_phdr.h
index db15ac9..6b72caf 100644
--- a/linker/linker_phdr.h
+++ b/linker/linker_phdr.h
@@ -45,10 +45,10 @@ class ElfReader {
   bool Load();
 
   size_t phdr_count() { return phdr_num_; }
-  Elf_Addr load_start() { return reinterpret_cast<Elf_Addr>(load_start_); }
+  ElfW(Addr) load_start() { return reinterpret_cast<ElfW(Addr)>(load_start_); }
   size_t load_size() { return load_size_; }
-  Elf_Addr load_bias() { return load_bias_; }
-  const Elf_Phdr* loaded_phdr() { return loaded_phdr_; }
+  ElfW(Addr) load_bias() { return load_bias_; }
+  const ElfW(Phdr)* loaded_phdr() { return loaded_phdr_; }
 
  private:
   bool ReadElfHeader();
@@ -57,46 +57,46 @@ class ElfReader {
   bool ReserveAddressSpace();
   bool LoadSegments();
   bool FindPhdr();
-  bool CheckPhdr(Elf_Addr);
+  bool CheckPhdr(ElfW(Addr));
 
   const char* name_;
   int fd_;
 
-  Elf_Ehdr header_;
+  ElfW(Ehdr) header_;
   size_t phdr_num_;
 
   void* phdr_mmap_;
-  Elf_Phdr* phdr_table_;
-  Elf_Addr phdr_size_;
+  ElfW(Phdr)* phdr_table_;
+  ElfW(Addr) phdr_size_;
 
   // First page of reserved address space.
   void* load_start_;
   // Size in bytes of reserved address space.
   size_t load_size_;
   // Load bias.
-  Elf_Addr load_bias_;
+  ElfW(Addr) load_bias_;
 
   // Loaded phdr.
-  const Elf_Phdr* loaded_phdr_;
+  const ElfW(Phdr)* loaded_phdr_;
 };
 
-size_t phdr_table_get_load_size(const Elf_Phdr* phdr_table, size_t phdr_count,
-                                Elf_Addr* min_vaddr = NULL, Elf_Addr* max_vaddr = NULL);
+size_t phdr_table_get_load_size(const ElfW(Phdr)* phdr_table, size_t phdr_count,
+                                ElfW(Addr)* min_vaddr = NULL, ElfW(Addr)* max_vaddr = NULL);
 
-int phdr_table_protect_segments(const Elf_Phdr* phdr_table, size_t phdr_count, Elf_Addr load_bias);
+int phdr_table_protect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
 
-int phdr_table_unprotect_segments(const Elf_Phdr* phdr_table, size_t phdr_count, Elf_Addr load_bias);
+int phdr_table_unprotect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
 
-int phdr_table_protect_gnu_relro(const Elf_Phdr* phdr_table, size_t phdr_count, Elf_Addr load_bias);
+int phdr_table_protect_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
 
 
 #if defined(__arm__)
-int phdr_table_get_arm_exidx(const Elf_Phdr* phdr_table, size_t phdr_count, Elf_Addr load_bias,
-                             Elf_Addr** arm_exidx, unsigned* arm_exidix_count);
+int phdr_table_get_arm_exidx(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
+                             ElfW(Addr)** arm_exidx, unsigned* arm_exidix_count);
 #endif
 
-void phdr_table_get_dynamic_section(const Elf_Phdr* phdr_table, size_t phdr_count,
-                                    Elf_Addr load_bias,
-                                    Elf_Dyn** dynamic, size_t* dynamic_count, Elf_Word* dynamic_flags);
+void phdr_table_get_dynamic_section(const ElfW(Phdr)* phdr_table, size_t phdr_count,
+                                    ElfW(Addr) load_bias,
+                                    ElfW(Dyn)** dynamic, size_t* dynamic_count, ElfW(Word)* dynamic_flags);
 
 #endif /* LINKER_PHDR_H */