Revert "Add a RTS option -xp to load PIC object anywhere in address space"

This reverts commit 5403a8636fe82f971234873564f3a05393b89b7a.

9 files changed, 94 insertions, 151 deletions

diff --git a/docs/users_guide/8.8.1-notes.rst b/docs/users_guide/8.8.1-notes.rst
index 75645e4690..37bad13b5b 100644
--- a/docs/users_guide/8.8.1-notes.rst
+++ b/docs/users_guide/8.8.1-notes.rst
@@ -80,10 +80,6 @@ Runtime system
   alignment, lower the amount of wasted memory and lower the amount of in use memory.
   See :ghc-ticket:`13617`. Note that committed memory may be slightly higher.
 
-- A new flag ``-xp`` is added on x86_64. When it is passed, the runtime linker
-  can load object files compiled with ``-fPIC -fexternal-dynamic-refs``
-  anywhere in the address space. This used to be restricted to the low 2Gb.
-
 
 Template Haskell
 ~~~~~~~~~~~~~~~~
diff --git a/docs/users_guide/runtime_control.rst b/docs/users_guide/runtime_control.rst
index 674b8f73ac..0c38ac5919 100644
--- a/docs/users_guide/runtime_control.rst
+++ b/docs/users_guide/runtime_control.rst
@@ -241,28 +241,6 @@ Miscellaneous RTS options
     crashes if exception handling are enabled. In order to get more information
     in compiled executables, C code or DLLs symbols need to be available.
 
-
-.. rts-flag:: -xp
-
-    On 64-bit machines, the runtime linker usually needs to map object code
-    into the low 2Gb of the address space, due to the x86_64 small memory model
-    where most symbol references are 32 bits. The problem is that this 2Gb of
-    address space can fill up, especially if you're loading a very large number
-    of object files into GHCi.
-
-    This flag offers a workaround, albeit a slightly convoluted one. To be able
-    to load an object file outside of the low 2Gb, the object code needs to be
-    compiled with ``-fPIC -fexternal-dynamic-refs``. When the ``+RTS -xp`` flag
-    is passed, the linker will assume that all object files were compiled with
-    ``-fPIC -fexternal-dynamic-refs`` and load them anywhere in the address
-    space. It's up to you to arrange that the object files you load (including
-    all packages) were compiled in the right way. If this is not the case for
-    an object, the linker will probably fail with an error message when the
-    problem is detected.
-
-    On some platforms where PIC is always the case, e.g. x86_64 MacOS X, this
-    flag is enabled by default.
-
 .. rts-flag:: -xm ⟨address⟩
 
     .. index::
@@ -272,10 +250,8 @@ Miscellaneous RTS options
 
         This option is for working around memory allocation
         problems only. Do not use unless GHCi fails with a message like
-        “\ ``failed to mmap() memory below 2Gb``\ ”. Consider recompiling
-        the objects with ``-fPIC -fexternal-dynamic-refs`` and using the
-        ``-xp`` flag instead. If you need to use this option to get GHCi
-        working on your machine, please file a bug.
+        “\ ``failed to mmap() memory below 2Gb``\ ”. If you need to use this
+        option to get GHCi working on your machine, please file a bug.
 
     On 64-bit machines, the RTS needs to allocate memory in the low 2Gb
     of the address space. Support for this across different operating
diff --git a/includes/rts/Flags.h b/includes/rts/Flags.h
index 723d8d0c17..6487947749 100644
--- a/includes/rts/Flags.h
+++ b/includes/rts/Flags.h
@@ -187,17 +187,6 @@ typedef struct _CONCURRENT_FLAGS {
  */
 #define DEFAULT_TICK_INTERVAL USToTime(10000)
 
-/*
- * When linkerAlwaysPic is true, the runtime linker assume that all object
- * files were compiled with -fPIC -fexternal-dynamic-refs and load them
- * anywhere in the address space.
- */
-#if defined(x86_64_HOST_ARCH) && defined(darwin_HOST_OS)
-#define DEFAULT_LINKER_ALWAYS_PIC true
-#else
-#define DEFAULT_LINKER_ALWAYS_PIC false
-#endif
-
 /* See Note [Synchronization of flags and base APIs] */
 typedef struct _MISC_FLAGS {
     Time    tickInterval;        /* units: TIME_RESOLUTION */
@@ -207,7 +196,6 @@ typedef struct _MISC_FLAGS {
     bool generate_stack_trace;
     bool machineReadable;
     bool internalCounters;       /* See Note [Internal Counter Stats] */
-    bool linkerAlwaysPic;        /* Assume the object code is always PIC */
     StgWord linkerMemBase;       /* address to ask the OS for memory
                                   * for the linker, NULL ==> off */
 } MISC_FLAGS;
diff --git a/libraries/base/GHC/RTS/Flags.hsc b/libraries/base/GHC/RTS/Flags.hsc
index 249bcd5a98..12cb828e6a 100644
--- a/libraries/base/GHC/RTS/Flags.hsc
+++ b/libraries/base/GHC/RTS/Flags.hsc
@@ -139,7 +139,6 @@ data MiscFlags = MiscFlags
     , generateStackTrace    :: Bool
     , machineReadable       :: Bool
     , internalCounters      :: Bool
-    , linkerAlwaysPic       :: Bool
     , linkerMemBase         :: Word
       -- ^ address to ask the OS for memory for the linker, 0 ==> off
     } deriving ( Show -- ^ @since 4.8.0.0
@@ -445,8 +444,6 @@ getMiscFlags = do
                   (#{peek MISC_FLAGS, machineReadable} ptr :: IO CBool))
             <*> (toBool <$>
                   (#{peek MISC_FLAGS, internalCounters} ptr :: IO CBool))
-            <*> (toBool <$>
-                  (#{peek MISC_FLAGS, linkerAlwaysPic} ptr :: IO CBool))
             <*> #{peek MISC_FLAGS, linkerMemBase} ptr
 
 getDebugFlags :: IO DebugFlags
diff --git a/rts/Linker.c b/rts/Linker.c
index b42a0de9c3..826269738b 100644
--- a/rts/Linker.c
+++ b/rts/Linker.c
@@ -72,6 +72,10 @@
 #  include <mach-o/fat.h>
 #endif
 
+#if defined(x86_64_HOST_ARCH) && defined(darwin_HOST_OS)
+#define ALWAYS_PIC
+#endif
+
 #if defined(dragonfly_HOST_OS)
 #include <sys/tls.h>
 #endif
@@ -208,7 +212,9 @@ int ocTryLoad( ObjectCode* oc );
  * We pick a default address based on the OS, but also make this
  * configurable via an RTS flag (+RTS -xm)
  */
-#if defined(MAP_32BIT) || DEFAULT_LINKER_ALWAYS_PIC
+#if !defined(ALWAYS_PIC) && defined(x86_64_HOST_ARCH)
+
+#if defined(MAP_32BIT)
 // Try to use MAP_32BIT
 #define MMAP_32BIT_BASE_DEFAULT 0
 #else
@@ -217,6 +223,7 @@ int ocTryLoad( ObjectCode* oc );
 #endif
 
 static void *mmap_32bit_base = (void *)MMAP_32BIT_BASE_DEFAULT;
+#endif
 
 static void ghciRemoveSymbolTable(HashTable *table, const SymbolName* key,
     ObjectCode *owner)
@@ -489,10 +496,12 @@ initLinker_ (int retain_cafs)
     }
 #   endif
 
+#if !defined(ALWAYS_PIC) && defined(x86_64_HOST_ARCH)
     if (RtsFlags.MiscFlags.linkerMemBase != 0) {
         // User-override for mmap_32bit_base
         mmap_32bit_base = (void*)RtsFlags.MiscFlags.linkerMemBase;
     }
+#endif
 
     if (RTS_LINKER_USE_MMAP)
         m32_allocator_init();
@@ -1000,30 +1009,29 @@ mmapForLinker (size_t bytes, uint32_t flags, int fd, int offset)
    void *map_addr = NULL;
    void *result;
    size_t size;
-   uint32_t tryMap32Bit = RtsFlags.MiscFlags.linkerAlwaysPic
-     ? 0
-     : TRY_MAP_32BIT;
    static uint32_t fixed = 0;
 
    IF_DEBUG(linker, debugBelch("mmapForLinker: start\n"));
    size = roundUpToPage(bytes);
 
+#if !defined(ALWAYS_PIC) && defined(x86_64_HOST_ARCH)
 mmap_again:
 
    if (mmap_32bit_base != 0) {
        map_addr = mmap_32bit_base;
    }
+#endif
 
    IF_DEBUG(linker,
             debugBelch("mmapForLinker: \tprotection %#0x\n",
                        PROT_EXEC | PROT_READ | PROT_WRITE));
    IF_DEBUG(linker,
             debugBelch("mmapForLinker: \tflags      %#0x\n",
-                       MAP_PRIVATE | tryMap32Bit | fixed | flags));
+                       MAP_PRIVATE | TRY_MAP_32BIT | fixed | flags));
 
    result = mmap(map_addr, size,
                  PROT_EXEC|PROT_READ|PROT_WRITE,
-                 MAP_PRIVATE|tryMap32Bit|fixed|flags, fd, offset);
+                 MAP_PRIVATE|TRY_MAP_32BIT|fixed|flags, fd, offset);
 
    if (result == MAP_FAILED) {
        sysErrorBelch("mmap %" FMT_Word " bytes at %p",(W_)size,map_addr);
@@ -1031,9 +1039,8 @@ mmap_again:
        return NULL;
    }
 
-#if defined(x86_64_HOST_ARCH)
-   if (RtsFlags.MiscFlags.linkerAlwaysPic) {
-   } else if (mmap_32bit_base != 0) {
+#if !defined(ALWAYS_PIC) && defined(x86_64_HOST_ARCH)
+   if (mmap_32bit_base != 0) {
        if (result == map_addr) {
            mmap_32bit_base = (StgWord8*)map_addr + size;
        } else {
@@ -1201,10 +1208,10 @@ void freeObjectCode (ObjectCode *oc)
 #if defined(NEED_SYMBOL_EXTRAS) && (!defined(x86_64_HOST_ARCH) \
                                     || !defined(mingw32_HOST_OS))
     if (RTS_LINKER_USE_MMAP) {
-      if (!USE_CONTIGUOUS_MMAP && !RtsFlags.MiscFlags.linkerAlwaysPic &&
-          oc->symbol_extras != NULL) {
-        m32_free(oc->symbol_extras, sizeof(SymbolExtra) * oc->n_symbol_extras);
-      }
+        if (!USE_CONTIGUOUS_MMAP && oc->symbol_extras != NULL) {
+            m32_free(oc->symbol_extras,
+                    sizeof(SymbolExtra) * oc->n_symbol_extras);
+        }
     }
     else {
         stgFree(oc->symbol_extras);
@@ -1497,21 +1504,32 @@ HsInt loadOc (ObjectCode* oc)
    }
 
    /* Note [loadOc orderings]
-      The order of `ocAllocateSymbolExtras` and `ocGetNames` matters. For MachO
-      and ELF, `ocInit` and `ocGetNames` initialize a bunch of pointers based
-      on the offset to `oc->image`, but `ocAllocateSymbolExtras` may relocate
-      the address of `oc->image` and invalidate those pointers. So we must
-      compute or recompute those pointers after `ocAllocateSymbolExtras`.
+      ocAllocateSymbolsExtras has only two pre-requisites, it must run after
+      preloadObjectFile and ocVerify.   Neither have changed.   On most targets
+      allocating the extras is independent on parsing the section data, so the
+      order between these two never mattered.
 
       On Windows, when we have an import library we (for now, as we don't honor
       the lazy loading semantics of the library and instead GHCi is already
       lazy) don't use the library after ocGetNames as it just populates the
       symbol table.  Allocating space for jump tables in ocAllocateSymbolExtras
       would just be a waste then as we'll be stopping further processing of the
-      library in the next few steps. If necessary, the actual allocation
-      happens in `ocGetNames_PEi386` and `ocAllocateSymbolExtras_PEi386` simply
-      set the correct pointers.
-      */
+      library in the next few steps.  */
+
+   /* build the symbol list for this image */
+#  if defined(OBJFORMAT_ELF)
+   r = ocGetNames_ELF ( oc );
+#  elif defined(OBJFORMAT_PEi386)
+   r = ocGetNames_PEi386 ( oc );
+#  elif defined(OBJFORMAT_MACHO)
+   r = ocGetNames_MachO ( oc );
+#  else
+   barf("loadObj: no getNames method");
+#  endif
+   if (!r) {
+       IF_DEBUG(linker, debugBelch("loadOc: ocGetNames_* failed\n"));
+       return r;
+   }
 
 #if defined(NEED_SYMBOL_EXTRAS)
 #  if defined(OBJFORMAT_MACHO)
@@ -1528,24 +1546,7 @@ HsInt loadOc (ObjectCode* oc)
                 debugBelch("loadOc: ocAllocateSymbolExtras_ELF failed\n"));
        return r;
    }
-#  endif
-
-   /* build the symbol list for this image */
-#  if defined(OBJFORMAT_ELF)
-   r = ocGetNames_ELF ( oc );
 #  elif defined(OBJFORMAT_PEi386)
-   r = ocGetNames_PEi386 ( oc );
-#  elif defined(OBJFORMAT_MACHO)
-   r = ocGetNames_MachO ( oc );
-#  else
-   barf("loadObj: no getNames method");
-#  endif
-   if (!r) {
-       IF_DEBUG(linker, debugBelch("loadOc: ocGetNames_* failed\n"));
-       return r;
-   }
-
-#  if defined(OBJFORMAT_PEi386)
    ocAllocateSymbolExtras_PEi386 ( oc );
 #  endif
 #endif
@@ -1829,3 +1830,4 @@ addSection (Section *s, SectionKind kind, SectionAlloc alloc,
                        start, (void*)((StgWord)start + size),
                        size, kind ));
 }
+
diff --git a/rts/RtsFlags.c b/rts/RtsFlags.c
index 6aecd90ca4..6a72e67859 100644
--- a/rts/RtsFlags.c
+++ b/rts/RtsFlags.c
@@ -235,7 +235,6 @@ void initRtsFlagsDefaults(void)
     RtsFlags.MiscFlags.generate_dump_file      = false;
     RtsFlags.MiscFlags.machineReadable         = false;
     RtsFlags.MiscFlags.internalCounters        = false;
-    RtsFlags.MiscFlags.linkerAlwaysPic         = DEFAULT_LINKER_ALWAYS_PIC;
     RtsFlags.MiscFlags.linkerMemBase           = 0;
 
 #if defined(THREADED_RTS)
@@ -454,11 +453,6 @@ usage_text[] = {
 "  -e<n>     Maximum number of outstanding local sparks (default: 4096)",
 #endif
 #if defined(x86_64_HOST_ARCH)
-#if !DEFAULT_LINKER_ALWAYS_PIC
-"  -xp       Assume that all object files were compiled with -fPIC",
-"            -fexternal-dynamic-refs and load them anywhere in the address",
-"            space",
-#endif
 "  -xm       Base address to mmap memory in the GHCi linker",
 "            (hex; must be <80000000)",
 #endif
@@ -1481,11 +1475,6 @@ error = true;
                     break;
 
 #if defined(x86_64_HOST_ARCH)
-                case 'p': /* linkerAlwaysPic */
-                    OPTION_UNSAFE;
-                    RtsFlags.MiscFlags.linkerAlwaysPic = true;
-                    break;
-
                 case 'm': /* linkerMemBase */
                     OPTION_UNSAFE;
                     if (rts_argv[arg][3] != '\0') {
diff --git a/rts/linker/Elf.c b/rts/linker/Elf.c
index fe87aed0b0..fd24a92630 100644
--- a/rts/linker/Elf.c
+++ b/rts/linker/Elf.c
@@ -169,8 +169,6 @@ get_shndx_table(Elf_Ehdr* ehdr)
 void
 ocInit_ELF(ObjectCode * oc)
 {
-    ocDeinit_ELF(oc);
-
     oc->info = (struct ObjectCodeFormatInfo*)stgCallocBytes(
             1, sizeof *oc->info,
             "ocInit_Elf(ObjectCodeFormatInfo)");
@@ -320,7 +318,6 @@ ocDeinit_ELF(ObjectCode * oc)
         }
 
         stgFree(oc->info);
-        oc->info = NULL;
     }
 }
 
@@ -757,7 +754,7 @@ ocGetNames_ELF ( ObjectCode* oc )
           start = mem;
           mapped_start = mem;
 #else
-          if (USE_CONTIGUOUS_MMAP || RtsFlags.MiscFlags.linkerAlwaysPic) {
+          if (USE_CONTIGUOUS_MMAP) {
               // already mapped.
               start = oc->image + offset;
               alloc = SECTION_NOMEM;
@@ -1587,6 +1584,9 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
 
       case COMPAT_R_X86_64_PC32:
       {
+#if defined(ALWAYS_PIC)
+          barf("R_X86_64_PC32 relocation, but ALWAYS_PIC.");
+#else
           StgInt64 off = value - P;
           if (off != (Elf64_Sword)off && X86_64_ELF_NONPIC_HACK) {
               StgInt64 pltAddress =
@@ -1603,6 +1603,7 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
           }
           Elf64_Sword payload = off;
           memcpy((void*)P, &payload, sizeof(payload));
+#endif
           break;
       }
 
@@ -1615,6 +1616,9 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
 
       case COMPAT_R_X86_64_32:
       {
+#if defined(ALWAYS_PIC)
+          barf("R_X86_64_32 relocation, but ALWAYS_PIC.");
+#else
           if (value != (Elf64_Word)value && X86_64_ELF_NONPIC_HACK) {
               StgInt64 pltAddress =
                   (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S)
@@ -1630,11 +1634,15 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
           }
           Elf64_Word payload = value;
           memcpy((void*)P, &payload, sizeof(payload));
+#endif
           break;
       }
 
       case COMPAT_R_X86_64_32S:
       {
+#if defined(ALWAYS_PIC)
+          barf("R_X86_64_32S relocation, but ALWAYS_PIC.");
+#else
           if ((StgInt64)value != (Elf64_Sword)value && X86_64_ELF_NONPIC_HACK) {
               StgInt64 pltAddress =
                   (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S)
@@ -1650,6 +1658,7 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
           }
           Elf64_Sword payload = value;
           memcpy((void*)P, &payload, sizeof(payload));
+#endif
           break;
       }
       case COMPAT_R_X86_64_REX_GOTPCRELX:
@@ -1671,6 +1680,9 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
 #if defined(dragonfly_HOST_OS)
       case COMPAT_R_X86_64_GOTTPOFF:
       {
+#if defined(ALWAYS_PIC)
+          barf("R_X86_64_GOTTPOFF relocation, but ALWAYS_PIC.");
+#else
         /* determine the offset of S to the current thread's tls
            area
            XXX: Move this to the beginning of function */
@@ -1688,12 +1700,16 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
           }
           Elf64_SWord payload = off;
           memcpy((void*)P, &payload, sizeof(payload));
+#endif
           break;
       }
 #endif
 
       case COMPAT_R_X86_64_PLT32:
       {
+#if defined(ALWAYS_PIC)
+          barf("R_X86_64_PLT32 relocation, but ALWAYS_PIC.");
+#else
           StgInt64 off = value - P;
           if (off != (Elf64_Sword)off) {
               StgInt64 pltAddress = (StgInt64) &makeSymbolExtra(oc, ELF_R_SYM(info), S)
@@ -1708,6 +1724,7 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
           }
           Elf64_Sword payload = off;
           memcpy((void*)P, &payload, sizeof(payload));
+#endif
           break;
       }
 #endif
diff --git a/rts/linker/MachO.c b/rts/linker/MachO.c
index ff8ef7a1e4..5812e89cda 100644
--- a/rts/linker/MachO.c
+++ b/rts/linker/MachO.c
@@ -99,8 +99,6 @@ bool ocMprotect_MachO( ObjectCode *oc );
 void
 ocInit_MachO(ObjectCode * oc)
 {
-    ocDeinit_MachO(oc);
-
     oc->info = (struct ObjectCodeFormatInfo*)stgCallocBytes(
                 1, sizeof *oc->info,
                 "ocInit_MachO(ObjectCodeFormatInfo)");
@@ -162,19 +160,16 @@ ocInit_MachO(ObjectCode * oc)
 
 void
 ocDeinit_MachO(ObjectCode * oc) {
-    if (oc->info != NULL) {
-        if(oc->info->n_macho_symbols > 0) {
-            stgFree(oc->info->macho_symbols);
-        }
+    if(oc->info->n_macho_symbols > 0) {
+        stgFree(oc->info->macho_symbols);
+    }
 #if defined(aarch64_HOST_ARCH)
-        freeGot(oc);
-        for(int i = 0; i < oc->n_sections; i++) {
-            freeStubs(&oc->sections[i]);
-        }
-#endif
-        stgFree(oc->info);
-        oc->info = NULL;
+    freeGot(oc);
+    for(int i = 0; i < oc->n_sections; i++) {
+        freeStubs(&oc->sections[i]);
     }
+#endif
+    stgFree(oc->info);
 }
 
 static int
diff --git a/rts/linker/SymbolExtras.c b/rts/linker/SymbolExtras.c
index 4c40b10877..88541f44d0 100644
--- a/rts/linker/SymbolExtras.c
+++ b/rts/linker/SymbolExtras.c
@@ -19,12 +19,6 @@
 #include "linker/SymbolExtras.h"
 #include "linker/M32Alloc.h"
 
-#if defined(OBJFORMAT_ELF)
-#  include "linker/Elf.h"
-#elif defined(OBJFORMAT_MACHO)
-#  include "linker/MachO.h"
-#endif
-
 #include <string.h>
 #if RTS_LINKER_USE_MMAP
 #include <sys/mman.h>
@@ -52,24 +46,8 @@
 int ocAllocateSymbolExtras( ObjectCode* oc, int count, int first )
 {
   size_t n;
-  void* oldImage = oc->image;
-
-  if (count > 0) {
-    if (!RTS_LINKER_USE_MMAP) {
-
-      // round up to the nearest 4
-      int aligned = (oc->fileSize + 3) & ~3;
-      int misalignment = oc->misalignment;
 
-      oc->image -= misalignment;
-      oc->image = stgReallocBytes( oc->image,
-                               misalignment +
-                               aligned + sizeof (SymbolExtra) * count,
-                               "ocAllocateSymbolExtras" );
-      oc->image += misalignment;
-
-      oc->symbol_extras = (SymbolExtra *) (oc->image + aligned);
-    } else if (USE_CONTIGUOUS_MMAP || RtsFlags.MiscFlags.linkerAlwaysPic) {
+  if (RTS_LINKER_USE_MMAP && USE_CONTIGUOUS_MMAP) {
       n = roundUpToPage(oc->fileSize);
 
       /* Keep image and symbol_extras contiguous */
@@ -85,37 +63,42 @@ int ocAllocateSymbolExtras( ObjectCode* oc, int count, int first )
           oc->imageMapped = true;
           oc->fileSize = n + (sizeof(SymbolExtra) * count);
           oc->symbol_extras = (SymbolExtra *) (oc->image + n);
-          if (mprotect(new, allocated_size,
-                       PROT_READ | PROT_WRITE | PROT_EXEC) != 0) {
-            sysErrorBelch("unable to protect memory");
+          if(mprotect(new, allocated_size, PROT_READ | PROT_EXEC) != 0) {
+              sysErrorBelch("unable to protect memory");
           }
       }
       else {
           oc->symbol_extras = NULL;
           return 0;
       }
-    } else {
+  }
+  else if( count > 0 ) {
+    if (RTS_LINKER_USE_MMAP) {
+        n = roundUpToPage(oc->fileSize);
+
         oc->symbol_extras = m32_alloc(sizeof(SymbolExtra) * count, 8);
         if (oc->symbol_extras == NULL) return 0;
     }
+    else {
+        // round up to the nearest 4
+        int aligned = (oc->fileSize + 3) & ~3;
+        int misalignment = oc->misalignment;
+
+        oc->image -= misalignment;
+        oc->image = stgReallocBytes( oc->image,
+                                 misalignment +
+                                 aligned + sizeof (SymbolExtra) * count,
+                                 "ocAllocateSymbolExtras" );
+        oc->image += misalignment;
+
+        oc->symbol_extras = (SymbolExtra *) (oc->image + aligned);
+    }
   }
 
   if (oc->symbol_extras != NULL) {
       memset( oc->symbol_extras, 0, sizeof (SymbolExtra) * count );
   }
 
-  // ObjectCodeFormatInfo contains computed addresses based on offset to
-  // image, if the address of image changes, we need to invalidate
-  // the ObjectCodeFormatInfo and recompute it.
-  if (oc->image != oldImage) {
-#if defined(OBJFORMAT_MACHO)
-    ocInit_MachO( oc );
-#endif
-#if defined(OBJFORMAT_ELF)
-    ocInit_ELF( oc );
-#endif
-  }
-
   oc->first_symbol_extra = first;
   oc->n_symbol_extras = count;