[project @ 2003-10-29 16:12:00 by wolfgang]

Add support for .bss (zero-initialized) sections on Mac OS X

Merge to stable.

diff --git a/ghc/rts/Linker.c b/ghc/rts/Linker.c
index 7a9e363..73f69e2 100644 (file)
--- a/ghc/rts/Linker.c
+++ b/ghc/rts/Linker.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: Linker.c,v 1.137 2003/10/08 10:37:25 wolfgang Exp $
+ * $Id: Linker.c,v 1.138 2003/10/29 16:12:00 wolfgang Exp $
  *
  * (c) The GHC Team, 2000-2003
  *
@@ -3000,13 +3000,11 @@ ia64_reloc_pcrel21(Elf_Addr target, Elf_Addr value, ObjectCode *oc)
 #if defined(OBJFORMAT_MACHO)
 
 /*
-  Initial support for MachO linking on Darwin/MacOS X on PowerPC chips
+  Support for MachO linking on Darwin/MacOS X on PowerPC chips
   by Wolfgang Thaller (wolfgang.thaller@gmx.net)
   
   I hereby formally apologize for the hackish nature of this code.
   Things that need to be done:
-  *) handle uninitialized data sections ("__common").
-       Normal common definitions work, but beware if you pass -fno-common to gcc.
   *) implement ocVerifyImage_MachO
   *) add still more sanity checks.
 */
@@ -3134,11 +3132,31 @@ static void* makeJumpIsland(
     return (void*) island;
 }
 
+static char* relocateAddress(
+    ObjectCode* oc,
+    int nSections,
+    struct section* sections,
+    unsigned long address)
+{  
+    int i;
+    for(i = 0; i < nSections; i++)
+    {
+        if(sections[i].addr <= address
+            && address < sections[i].addr + sections[i].size)
+        {
+            return oc->image + sections[i].offset + address - sections[i].addr;
+        }
+    }
+    barf("Invalid Mach-O file:"
+         "Address out of bounds while relocating object file");
+    return NULL;
+}
+
 static int relocateSection(
     ObjectCode* oc,
     char *image, 
     struct symtab_command *symLC, struct nlist *nlist,
-    struct section* sections, struct section *sect)
+    int nSections, struct section* sections, struct section *sect)
 {
     struct relocation_info *relocs;
     int i,n;
@@ -3160,12 +3178,55 @@ static int relocateSection(
            
            if(!scat->r_pcrel)
            {
-               if(scat->r_length == 2 && scat->r_type == GENERIC_RELOC_VANILLA)
+               if(scat->r_length == 2)
                {
-                   unsigned long* word = (unsigned long*) (image + sect->offset + scat->r_address);
+                   unsigned long word = 0;
+                   unsigned long* wordPtr = (unsigned long*) (image + sect->offset + scat->r_address);
+                   checkProddableBlock(oc,wordPtr);
                    
-                   checkProddableBlock(oc,word);
-                   *word = scat->r_value + sect->offset + ((long) image);
+                   // Step 1: Figure out what the relocated value should be
+                   if(scat->r_type == GENERIC_RELOC_VANILLA)
+                   {
+                       word = scat->r_value + sect->offset + ((long) image);
+                   }
+                   else if(scat->r_type == PPC_RELOC_SECTDIFF
+                       || scat->r_type == PPC_RELOC_LO16_SECTDIFF
+                       || scat->r_type == PPC_RELOC_HI16_SECTDIFF
+                       || scat->r_type == PPC_RELOC_HA16_SECTDIFF)
+                   {
+                       struct scattered_relocation_info *pair =
+                               (struct scattered_relocation_info*) &relocs[i+1];
+                               
+                       if(!pair->r_scattered || pair->r_type != PPC_RELOC_PAIR)
+                           barf("Invalid Mach-O file: "
+                                "PPC_RELOC_*_SECTDIFF not followed by PPC_RELOC_PAIR");
+                       
+                       word = (unsigned long)
+                              (relocateAddress(oc, nSections, sections, scat->r_value)
+                             - relocateAddress(oc, nSections, sections, pair->r_value));
+                       i++;
+                   }
+                   else
+                       continue;  // ignore the others
+
+                    if(scat->r_type == GENERIC_RELOC_VANILLA
+                        || scat->r_type == PPC_RELOC_SECTDIFF)
+                    {
+                        *wordPtr = word;
+                    }
+                    else if(scat->r_type == PPC_RELOC_LO16_SECTDIFF)
+                    {
+                        ((unsigned short*) wordPtr)[1] = word & 0xFFFF;
+                    }
+                    else if(scat->r_type == PPC_RELOC_HI16_SECTDIFF)
+                    {
+                        ((unsigned short*) wordPtr)[1] = (word >> 16) & 0xFFFF;
+                    }
+                    else if(scat->r_type == PPC_RELOC_HA16_SECTDIFF)
+                    {
+                        ((unsigned short*) wordPtr)[1] = ((word >> 16) & 0xFFFF)
+                            + ((word & (1<<15)) ? 1 : 0);
+                    }
                }
            }
            
@@ -3298,7 +3359,7 @@ static int ocGetNames_MachO(ObjectCode* oc)
     struct load_command *lc = (struct load_command*) (image + sizeof(struct mach_header));
     unsigned i,curSymbol;
     struct segment_command *segLC = NULL;
-    struct section *sections, *la_ptrs = NULL, *nl_ptrs = NULL;
+    struct section *sections;
     struct symtab_command *symLC = NULL;
     struct dysymtab_command *dsymLC = NULL;
     struct nlist *nlist;
@@ -3322,13 +3383,17 @@ static int ocGetNames_MachO(ObjectCode* oc)
 
     for(i=0;i<segLC->nsects;i++)
     {
-       if(!strcmp(sections[i].sectname,"__la_symbol_ptr"))
-           la_ptrs = &sections[i];
-       else if(!strcmp(sections[i].sectname,"__nl_symbol_ptr"))
-           nl_ptrs = &sections[i];
-           
-           // for now, only add __text and __const to the sections table
-       else if(!strcmp(sections[i].sectname,"__text"))
+        if(sections[i].size == 0)
+            continue;
+        
+        if((sections[i].flags & SECTION_TYPE) == S_ZEROFILL)
+        {
+            char * zeroFillArea = stgCallocBytes(1,sections[i].size,
+                                      "ocGetNames_MachO(common symbols)");
+            sections[i].offset = zeroFillArea - image;
+        }
+    
+       if(!strcmp(sections[i].sectname,"__text"))
            addSection(oc, SECTIONKIND_CODE_OR_RODATA, 
                (void*) (image + sections[i].offset),
                (void*) (image + sections[i].offset + sections[i].size));
@@ -3340,10 +3405,14 @@ static int ocGetNames_MachO(ObjectCode* oc)
            addSection(oc, SECTIONKIND_RWDATA, 
                (void*) (image + sections[i].offset),
                (void*) (image + sections[i].offset + sections[i].size));
-               
-       if(sections[i].size > 0)    // size 0 segments do exist
-           addProddableBlock(oc, (void*) (image + sections[i].offset),
-                                           sections[i].size);
+       else if(!strcmp(sections[i].sectname,"__bss")
+               || !strcmp(sections[i].sectname,"__common"))
+           addSection(oc, SECTIONKIND_RWDATA, 
+               (void*) (image + sections[i].offset),
+               (void*) (image + sections[i].offset + sections[i].size));
+
+        addProddableBlock(oc, (void*) (image + sections[i].offset),
+                                        sections[i].size);
     }
 
        // count external symbols defined here
@@ -3460,7 +3529,7 @@ static int ocResolve_MachO(ObjectCode* oc)
     
     for(i=0;i<segLC->nsects;i++)
     {
-       if(!relocateSection(oc,image,symLC,nlist,sections,&sections[i]))
+       if(!relocateSection(oc,image,symLC,nlist,segLC->nsects,sections,&sections[i]))
            return 0;
     }