Batch merge

1 files changed, 55 insertions, 57 deletions

diff --git a/rts/linker/Elf.c b/rts/linker/Elf.c
index 9ea10d443f..b647d207cb 100644
--- a/rts/linker/Elf.c
+++ b/rts/linker/Elf.c
@@ -53,11 +53,13 @@
  * SILENTLY generate crashing code for data references.  This hack is
  * enabled by X86_64_ELF_NONPIC_HACK.
  *
- * One workaround is to use shared Haskell libraries.  This is
- * coming.  Another workaround is to keep the static libraries but
- * compile them with -fPIC, because that will generate PIC references
- * to data which can be relocated.  The PIC code is still too green to
- * do this systematically, though.
+ * One workaround is to use shared Haskell libraries. This is the case
+ * when dynamically-linked GHCi is used.
+ *
+ * Another workaround is to keep the static libraries but compile them
+ * with -fPIC -fexternal-dynamic-refs, because that will generate PIC
+ * references to data which can be relocated. This is the case when
+ * +RTS -xp is passed.
  *
  * See bug #781
  * See thread http://www.haskell.org/pipermail/cvs-ghc/2007-September/038458.html
@@ -74,7 +76,7 @@
  * Sym*_NeedsProto: the symbol is undefined and we add a dummy
  *                  default proto extern void sym(void);
  */
-#define X86_64_ELF_NONPIC_HACK 1
+#define X86_64_ELF_NONPIC_HACK (!RtsFlags.MiscFlags.linkerAlwaysPic)
 
 #if defined(sparc_HOST_ARCH)
 #  define ELF_TARGET_SPARC  /* Used inside <elf.h> */
@@ -169,6 +171,8 @@ 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)");
@@ -318,6 +322,7 @@ ocDeinit_ELF(ObjectCode * oc)
         }
 
         stgFree(oc->info);
+        oc->info = NULL;
     }
 }
 
@@ -576,7 +581,7 @@ ocVerifyImage_ELF ( ObjectCode* oc )
 /* Figure out what kind of section it is.  Logic derived from
    Figure 1.14 ("Special Sections") of the ELF document
    ("Portable Formats Specification, Version 1.1"). */
-static int getSectionKind_ELF( Elf_Shdr *hdr, int *is_bss )
+static SectionKind getSectionKind_ELF( Elf_Shdr *hdr, int *is_bss )
 {
     *is_bss = false;
 
@@ -678,23 +683,31 @@ ocGetNames_ELF ( ObjectCode* oc )
       StgWord mapped_size = 0, mapped_offset = 0;
       StgWord size = shdr[i].sh_size;
       StgWord offset = shdr[i].sh_offset;
+      StgWord align = shdr[i].sh_addralign;
 
       if (is_bss && size > 0) {
          /* This is a non-empty .bss section.  Allocate zeroed space for
             it, and set its .sh_offset field such that
             ehdrC + .sh_offset == addr_of_zeroed_space.  */
-#if defined(NEED_GOT)
-          /* always use mmap if we use GOT slots.  Otherwise the malloced
-           * address might be out of range for sections that are mmaped.
-           */
-          alloc = SECTION_MMAP;
-          start = mmap(NULL, size,
-                       PROT_READ | PROT_WRITE | PROT_EXEC,
-                       MAP_ANON | MAP_PRIVATE,
-                       -1, 0);
-          mapped_start = start;
-          mapped_offset = 0;
-          mapped_size = roundUpToPage(size);
+#if defined(NEED_GOT) || RTS_LINKER_USE_MMAP
+          if (USE_CONTIGUOUS_MMAP || RtsFlags.MiscFlags.linkerAlwaysPic) {
+              /* The space for bss sections is already preallocated */
+              ASSERT(oc->bssBegin != NULL);
+              alloc = SECTION_NOMEM;
+              start =
+                oc->image + roundUpToAlign(oc->bssBegin - oc->image, align);
+              oc->bssBegin = (char*)start + size;
+              ASSERT(oc->bssBegin <= oc->bssEnd);
+          } else {
+              /* Use mmapForLinker to allocate .bss, otherwise the malloced
+               * address might be out of range for sections that are mmaped.
+               */
+              alloc = SECTION_MMAP;
+              start = mmapForLinker(size, MAP_ANONYMOUS, -1, 0);
+              mapped_start = start;
+              mapped_offset = 0;
+              mapped_size = roundUpToPage(size);
+          }
 #else
           alloc = SECTION_MALLOC;
           start = stgCallocBytes(1, size, "ocGetNames_ELF(BSS)");
@@ -754,7 +767,7 @@ ocGetNames_ELF ( ObjectCode* oc )
           start = mem;
           mapped_start = mem;
 #else
-          if (USE_CONTIGUOUS_MMAP) {
+          if (USE_CONTIGUOUS_MMAP || RtsFlags.MiscFlags.linkerAlwaysPic) {
               // already mapped.
               start = oc->image + offset;
               alloc = SECTION_NOMEM;
@@ -1585,9 +1598,6 @@ 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 =
@@ -1604,7 +1614,6 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
           }
           Elf64_Sword payload = off;
           memcpy((void*)P, &payload, sizeof(payload));
-#endif
           break;
       }
 
@@ -1617,9 +1626,6 @@ 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)
@@ -1635,15 +1641,11 @@ 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)
@@ -1659,7 +1661,6 @@ 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:
@@ -1681,9 +1682,6 @@ 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 */
@@ -1701,16 +1699,12 @@ 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)
@@ -1725,7 +1719,6 @@ do_Elf_Rela_relocations ( ObjectCode* oc, char* ehdrC,
           }
           Elf64_Sword payload = off;
           memcpy((void*)P, &payload, sizeof(payload));
-#endif
           break;
       }
 #endif
@@ -1891,22 +1884,27 @@ int ocRunInit_ELF( ObjectCode *oc )
 
 #if defined(NEED_SYMBOL_EXTRAS)
 
-int ocAllocateSymbolExtras_ELF( ObjectCode *oc )
+int ocAllocateExtras_ELF( ObjectCode *oc )
 {
-  Elf_Ehdr *ehdr;
-  Elf_Shdr* shdr;
-  Elf_Word i, shnum;
-
-  ehdr = (Elf_Ehdr *) oc->image;
-  shdr = (Elf_Shdr *) ( ((char *)oc->image) + ehdr->e_shoff );
-
-  shnum = elf_shnum(ehdr);
-
-  for( i = 0; i < shnum; i++ )
-    if( shdr[i].sh_type == SHT_SYMTAB )
-      break;
+  Elf_Ehdr *ehdr = (Elf_Ehdr *) oc->image;
+  Elf_Shdr* shdr = (Elf_Shdr *) ( ((char *)oc->image) + ehdr->e_shoff );
+  Elf_Shdr* symtab = NULL;
+  Elf_Word shnum = elf_shnum(ehdr);
+  int bssSize = 0;
+
+  for (Elf_Word i = 0; i < shnum; ++i) {
+    if(shdr[i].sh_type == SHT_SYMTAB) {
+      symtab = &shdr[i];
+    } else {
+      int isBss = 0;
+      getSectionKind_ELF(&shdr[i], &isBss);
+      if (isBss && shdr[i].sh_size > 0) {
+        bssSize += roundUpToAlign(shdr[i].sh_size, shdr[i].sh_addralign);
+      }
+    }
+  }
 
-  if( i == shnum )
+  if (symtab == NULL)
   {
     // Not having a symbol table is not in principle a problem.
     // When an object file has no symbols then the 'strip' program
@@ -1916,15 +1914,15 @@ int ocAllocateSymbolExtras_ELF( ObjectCode *oc )
     return 1;
   }
 
-  if( shdr[i].sh_entsize != sizeof( Elf_Sym ) )
+  if( symtab->sh_entsize != sizeof( Elf_Sym ) )
   {
     errorBelch( "The entry size (%d) of the symtab isn't %d\n",
-      (int) shdr[i].sh_entsize, (int) sizeof( Elf_Sym ) );
+      (int) symtab->sh_entsize, (int) sizeof( Elf_Sym ) );
 
     return 0;
   }
 
-  return ocAllocateSymbolExtras( oc, shdr[i].sh_size / sizeof( Elf_Sym ), 0 );
+  return ocAllocateExtras(oc, symtab->sh_size / sizeof( Elf_Sym ), 0, bssSize);
 }
 
 #endif /* NEED_SYMBOL_EXTRAS */