Properly handle external debuginfo (.gnu_debuglink) for stripped and

prelinked libraries (patch from L. David Baron).

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@5841

diff --git a/coregrind/m_debuginfo/priv_readdwarf.h b/coregrind/m_debuginfo/priv_readdwarf.h
index b77955e0f0dc11c7b5e8923e73e71a13ac35bd05..6ad589151e56f5eef7b27a02c639331966da707a 100644 (file)
--- a/coregrind/m_debuginfo/priv_readdwarf.h
+++ b/coregrind/m_debuginfo/priv_readdwarf.h
@@ -43,7 +43,7 @@
    -------------------- */
 extern
 void ML_(read_debuginfo_dwarf2)
-        ( struct _SegInfo* si,
+        ( struct _SegInfo* si, OffT debug_offset,
           UChar* debuginfo,   Int debug_info_sz,  /* .debug_info */
           UChar* debugabbrev,                     /* .debug_abbrev */
           UChar* debugline,   Int debug_line_sz,  /* .debug_line */

diff --git a/coregrind/m_debuginfo/priv_readstabs.h b/coregrind/m_debuginfo/priv_readstabs.h
index cc83de3227a08d15ec54e511b9231d1040e8bf1a..5f2ebc40899f0cfb98d295abc25c754780152e8e 100644 (file)
--- a/coregrind/m_debuginfo/priv_readstabs.h
+++ b/coregrind/m_debuginfo/priv_readstabs.h
@@ -41,7 +41,7 @@
    Stabs reader
    -------------------- */
 extern
-void ML_(read_debuginfo_stabs) ( struct _SegInfo* si,
+void ML_(read_debuginfo_stabs) ( struct _SegInfo* si, OffT debug_offset,
                                  UChar* stabC,   Int stab_sz,
                                  UChar* stabstr, Int stabstr_sz );
 

diff --git a/coregrind/m_debuginfo/priv_storage.h b/coregrind/m_debuginfo/priv_storage.h
index 396520927965e60cdb8bc7e97ba04e916136560d..d4e0eadecee66a9ac7e05b7ca4f5d351e4f9bb86 100644 (file)
--- a/coregrind/m_debuginfo/priv_storage.h
+++ b/coregrind/m_debuginfo/priv_storage.h
@@ -170,8 +170,10 @@ struct _SegInfo {
       UChar  strtab[SEGINFO_STRCHUNKSIZE];
    } *strchunks;
 
-   /* 'offset' is what we need to add to symbol table entries to get
-      the location of that symbol in the running image. */
+   /* 'offset' is what needs to be added to an address in the address
+      space of the library as stored on disk (which is not 0-based for
+      executables or prelinked libraries) to get an address in memory
+      for the object loaded at 'start' */
    OffT   offset;
 
    /* Bounds of data, BSS, PLT, GOT and OPD (for ppc64-linux) so that

diff --git a/coregrind/m_debuginfo/readdwarf.c b/coregrind/m_debuginfo/readdwarf.c
index 7b10ffff97fdccfda247b30f4c628b1e25c80707..94b95dd7779e0473ff93fc73e6cb9d3fbea598bb 100644 (file)
--- a/coregrind/m_debuginfo/readdwarf.c
+++ b/coregrind/m_debuginfo/readdwarf.c
@@ -301,7 +301,7 @@ Char* lookupDir ( Int filename_index,
 /* Handled an extend line op.  Returns true if this is the end
    of sequence.  */
 static 
-Int process_extended_line_op( struct _SegInfo* si, 
+Int process_extended_line_op( struct _SegInfo* si, OffT debug_offset,
                               WordArray* filenames, 
                               WordArray* dirnames, 
                               WordArray* fnidx2dir, 
@@ -330,7 +330,7 @@ Int process_extended_line_op( struct _SegInfo* si,
    switch (op_code) {
       case DW_LNE_end_sequence:
          if (0) VG_(printf)("1001: si->o %p, smr.a %p\n", 
-                            si->offset, state_machine_regs.address );
+                            debug_offset, state_machine_regs.address );
          /* JRS: added for compliance with spec; is pointless due to
             reset_state_machine below */
          state_machine_regs.end_sequence = 1; 
@@ -343,8 +343,8 @@ Int process_extended_line_op( struct _SegInfo* si,
                                          state_machine_regs.last_file), 
                   lookupDir( state_machine_regs.last_file,
                              fnidx2dir, dirnames ),
-                  si->offset + state_machine_regs.last_address, 
-                  si->offset + state_machine_regs.address, 
+                  debug_offset + state_machine_regs.last_address, 
+                  debug_offset + state_machine_regs.address, 
                   state_machine_regs.last_line, 0
                );
          }
@@ -388,7 +388,7 @@ Int process_extended_line_op( struct _SegInfo* si,
  * Output: - si debug info structures get updated
  */
 static 
-void read_dwarf2_lineblock ( struct _SegInfo*  si, 
+void read_dwarf2_lineblock ( struct _SegInfo*  si, OffT debug_offset,
                              UnitInfo* ui, 
                              UChar*    theBlock, 
                              Int       noLargerThan )
@@ -606,7 +606,7 @@ void read_dwarf2_lineblock ( struct _SegInfo*  si,
          if (0) VG_(printf)("smr.a += %p\n", adv );
          adv = (op_code % info.li_line_range) + info.li_line_base;
          if (0) VG_(printf)("1002: si->o %p, smr.a %p\n", 
-                            si->offset, state_machine_regs.address );
+                            debug_offset, state_machine_regs.address );
          state_machine_regs.line += adv;
 
          if (state_machine_regs.is_stmt) {
@@ -618,8 +618,8 @@ void read_dwarf2_lineblock ( struct _SegInfo*  si,
                                           state_machine_regs.last_file ),
                   lookupDir( state_machine_regs.last_file,
                              &fnidx2dir, &dirnames ),
-                  si->offset + state_machine_regs.last_address, 
-                  si->offset + state_machine_regs.address, 
+                  debug_offset + state_machine_regs.last_address, 
+                  debug_offset + state_machine_regs.address, 
                   state_machine_regs.last_line, 
                   0
                );
@@ -634,13 +634,13 @@ void read_dwarf2_lineblock ( struct _SegInfo*  si,
       switch (op_code) {
          case DW_LNS_extended_op:
             data += process_extended_line_op (
-                       si, &filenames, &dirnames, &fnidx2dir,
+                       si, debug_offset, &filenames, &dirnames, &fnidx2dir,
                        data, info.li_default_is_stmt);
             break;
 
          case DW_LNS_copy:
             if (0) VG_(printf)("1002: si->o %p, smr.a %p\n", 
-                               si->offset, state_machine_regs.address );
+                               debug_offset, state_machine_regs.address );
             if (state_machine_regs.is_stmt) {
                /* only add a statement if there was a previous boundary */
                if (state_machine_regs.last_address) 
@@ -650,8 +650,8 @@ void read_dwarf2_lineblock ( struct _SegInfo*  si,
                                              state_machine_regs.last_file ),
                      lookupDir( state_machine_regs.last_file,
                                 &fnidx2dir, &dirnames ),
-                     si->offset + state_machine_regs.last_address, 
-                     si->offset + state_machine_regs.address,
+                     debug_offset + state_machine_regs.last_address, 
+                     debug_offset + state_machine_regs.address,
                      state_machine_regs.last_line, 
                      0
                   );
@@ -950,7 +950,7 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
  * Output: update si to contain all the dwarf2 debug infos
  */
 void ML_(read_debuginfo_dwarf2) 
-        ( struct _SegInfo* si,
+        ( struct _SegInfo* si, OffT debug_offset,
           UChar* debuginfo,   Int debug_info_sz,  /* .debug_info */
           UChar* debugabbrev,                     /* .debug_abbrev */
           UChar* debugline,   Int debug_line_sz,  /* .debug_line */
@@ -1006,7 +1006,7 @@ void ML_(read_debuginfo_dwarf2)
          VG_(printf)("debug_line_sz %d, ui.stmt_list %lld  %s\n", 
                      debug_line_sz, ui.stmt_list, ui.name );
       /* Read the .debug_line block for this compile unit */
-      read_dwarf2_lineblock( si, &ui, debugline + ui.stmt_list, 
+      read_dwarf2_lineblock( si, debug_offset, &ui, debugline + ui.stmt_list, 
                                       debug_line_sz - ui.stmt_list );
    }
 }

diff --git a/coregrind/m_debuginfo/readelf.c b/coregrind/m_debuginfo/readelf.c
index 20ca620783a0eb724a2a85c3de97f8a831ed4429..be0d75fc3cdfe4d3c1dabf5f049b3c0a967f50da 100644 (file)
--- a/coregrind/m_debuginfo/readelf.c
+++ b/coregrind/m_debuginfo/readelf.c
@@ -192,6 +192,7 @@ Bool get_elf_symbol_info (
         Char*      sym_name,  /* name */
         Addr       sym_addr,  /* declared address */
         UChar*     opd_filea, /* oimage of .opd sec (ppc64-linux only) */
+        OffT       opd_offset, /* base address assumed in oimage */
         /* OUTPUTS */
         Char** sym_name_out,   /* name we should record */
         Addr*  sym_addr_out,   /* addr we should record */
@@ -293,8 +294,8 @@ Bool get_elf_symbol_info (
       Int    offset_in_opd;
       ULong* fn_descr;
 
-      if (0) VG_(printf)("opdXXX: si->offset %p, sym_addr %p\n", 
-                         (void*)(si->offset), (void*)sym_addr);
+      if (0) VG_(printf)("opdXXX: opd_offset %p, sym_addr %p\n", 
+                         (void*)(opd_offset), (void*)sym_addr);
 
       if (!VG_IS_8_ALIGNED(sym_addr)) {
          TRACE_SYMTAB("    ignore -- not 8-aligned: %s\n", sym_name);
@@ -323,17 +324,13 @@ Bool get_elf_symbol_info (
                          offset_in_opd, fn_descr);
       if (0) VG_(printf)("opdXXZ: *fn_descr %p\n", (void*)(fn_descr[0]));
 
-      sym_addr = fn_descr[0];
+      /* opd_offset is the difference between si->start (where the
+         library got mapped) and the address space used for addresses
+         within the library file. */
 
-      /* Hopefully sym_addr is now an offset into the text section.
-         Problem is, where did the text section get mapped?  Well,
-         this SegInfo (si) exists because a text section got mapped,
-         and it got mapped to si->start.  Hence add si->start to the
-         sym_addr to get the real vma. */
-
-      sym_addr += si->offset;
+      sym_addr        = fn_descr[0] + opd_offset;
       *sym_addr_out   = sym_addr;
-      *sym_tocptr_out = fn_descr[1] + si->offset;
+      *sym_tocptr_out = fn_descr[1] + opd_offset;
       *from_opd_out   = True;
       is_in_opd = True;
 
@@ -360,7 +357,9 @@ Bool get_elf_symbol_info (
       ignore it. */
    if (*sym_addr_out + *sym_size_out <= si->start
        || *sym_addr_out >= si->start+si->size) {
-      TRACE_SYMTAB( "   ignore -- outside mapped range\n" );
+      TRACE_SYMTAB( "ignore -- %p .. %p outside mapped range %p .. %p\n",
+                    *sym_addr_out, *sym_addr_out + *sym_size_out,
+                    si->start, si->start+si->size);
       return False;
    }
 
@@ -386,9 +385,9 @@ static
 __attribute__((unused)) /* not referred to on all targets */
 void read_elf_symtab__normal( 
         struct _SegInfo* si, UChar* tab_name,
-        ElfXX_Sym* o_symtab, UInt o_symtab_sz,
+        ElfXX_Sym* o_symtab, UInt o_symtab_sz, OffT o_symtab_offset,
         UChar*     o_strtab, UInt o_strtab_sz,
-        UChar*     opd_filea /* ppc64-linux only */ 
+        UChar*     opd_filea, OffT opd_offset /* ppc64-linux only */ 
      )
 {
    Int        i;
@@ -416,12 +415,13 @@ void read_elf_symtab__normal(
    for (i = 1; i < (Int)(o_symtab_sz/sizeof(ElfXX_Sym)); i++) {
       sym      = & o_symtab[i];
       sym_name = (Char*)(o_strtab + sym->st_name);
-      sym_addr = si->offset + sym->st_value;
+      sym_addr = o_symtab_offset + sym->st_value;
 
       if (VG_(clo_trace_symtab))
          show_raw_elf_symbol(i, sym, sym_name, sym_addr, False);
 
-      if (get_elf_symbol_info(si, sym, sym_name, sym_addr, opd_filea,
+      if (get_elf_symbol_info(si, sym, sym_name, sym_addr,
+                              opd_filea, opd_offset,
                               &sym_name_really, 
                               &sym_addr_really,
                               &sym_size,
@@ -484,9 +484,9 @@ static
 __attribute__((unused)) /* not referred to on all targets */
 void read_elf_symtab__ppc64_linux( 
         struct _SegInfo* si, UChar* tab_name,
-        ElfXX_Sym* o_symtab, UInt o_symtab_sz,
+        ElfXX_Sym* o_symtab, UInt o_symtab_sz, OffT o_symtab_offset,
         UChar*     o_strtab, UInt o_strtab_sz,
-        UChar*     opd_filea /* ppc64-linux only */ 
+        UChar*     opd_filea, OffT opd_offset /* ppc64-linux only */ 
      )
 {
    Int         i, old_size;
@@ -523,12 +523,13 @@ void read_elf_symtab__ppc64_linux(
    for (i = 1; i < (Int)(o_symtab_sz/sizeof(ElfXX_Sym)); i++) {
       sym      = & o_symtab[i];
       sym_name = (Char*)(o_strtab + sym->st_name);
-      sym_addr = si->offset + sym->st_value;
+      sym_addr = o_symtab_offset + sym->st_value;
 
       if (VG_(clo_trace_symtab))
          show_raw_elf_symbol(i, sym, sym_name, sym_addr, True);
 
-      if (get_elf_symbol_info(si, sym, sym_name, sym_addr, opd_filea,
+      if (get_elf_symbol_info(si, sym, sym_name, sym_addr,
+                              opd_filea, opd_offset,
                               &sym_name_really, 
                               &sym_addr_really,
                               &sym_size,
@@ -816,8 +817,10 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
    Bool          ok;
    Addr          oimage;
    UInt          n_oimage;
+   OffT          offset_oimage = 0;
    Addr          dimage = 0;
    UInt          n_dimage = 0;
+   OffT          offset_dimage = 0;
    struct vki_stat stat_buf;
 
    oimage = (Addr)NULL;
@@ -883,8 +886,6 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
       ElfXX_Addr prev_addr = 0;
       Addr baseaddr = 0;
 
-      si->offset = 0;
-
       vg_assert(si->soname == NULL);
 
       for (i = 0; i < ehdr->e_phnum; i++) {
@@ -926,7 +927,7 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
 
         if (!offset_set) {
            offset_set = True;
-           si->offset = si->start - o_phdr->p_vaddr;
+           offset_oimage = si->start - o_phdr->p_vaddr;
            baseaddr = o_phdr->p_vaddr;
         }
 
@@ -938,7 +939,7 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
         prev_addr = o_phdr->p_vaddr;
 
          // Get the data and bss start/size if appropriate
-        mapped = o_phdr->p_vaddr + si->offset;
+        mapped = o_phdr->p_vaddr + offset_oimage;
         mapped_end = mapped + o_phdr->p_memsz;
         if (si->data_start_vma == 0 &&
             (o_phdr->p_flags & (PF_R|PF_W|PF_X)) == (PF_R|PF_W)) {
@@ -970,6 +971,8 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
       }
    }
 
+   si->offset = offset_oimage;
+
    /* If, after looking at all the program headers, we still didn't 
       find a soname, add a fake one. */
    if (si->soname == NULL) {
@@ -1010,6 +1013,11 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
       UChar*     opd_filea    = NULL; /* .opd          (dwarf2, ppc64-linux) */
       UChar*     dummy_filea  = NULL;
 
+      OffT       o_symtab_offset = offset_oimage;
+      OffT       o_dynsym_offset = offset_oimage;
+      OffT       debug_offset    = offset_oimage;
+      OffT       opd_offset      = offset_oimage;
+
       /* Section sizes, in bytes */
       UInt       o_strtab_sz     = 0;
       UInt       o_symtab_sz     = 0;
@@ -1049,7 +1057,7 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
 #        define FIND(sec_name, sec_size, sec_filea, sec_vma) \
          if (0 == VG_(strcmp)(sec_name, sh_strtab + shdr[i].sh_name)) { \
             Bool nobits; \
-            sec_vma   = (Addr)(si->offset + shdr[i].sh_addr); \
+            sec_vma   = (Addr)(offset_oimage + shdr[i].sh_addr); \
             sec_filea = (void*)(oimage + shdr[i].sh_offset); \
             sec_size  = shdr[i].sh_size; \
             nobits = shdr[i].sh_type == SHT_NOBITS; \
@@ -1093,10 +1101,6 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
 #        undef FIND
       }
          
-      /* Check some sizes */
-      vg_assert((o_dynsym_sz % sizeof(ElfXX_Sym)) == 0);
-      vg_assert((o_symtab_sz % sizeof(ElfXX_Sym)) == 0);
-
       /* Did we find a debuglink section? */
       if (debuglink != NULL) {
          UInt crc_offset = VG_ROUNDUP(VG_(strlen)(debuglink)+1, 4);
@@ -1112,7 +1116,24 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
             ehdr = (ElfXX_Ehdr*)dimage;
 
             if (n_dimage >= sizeof(ElfXX_Ehdr) 
-                && ML_(is_elf_object_file(ehdr))) {
+                && ML_(is_elf_object_file(ehdr))
+                && ehdr->e_phoff + ehdr->e_phnum*sizeof(ElfXX_Phdr) <= n_dimage
+                && ehdr->e_shoff + ehdr->e_shnum*sizeof(ElfXX_Shdr) <= n_dimage)
+            {
+               Bool need_symtab = (NULL == o_symtab);
+
+               for (i = 0; i < ehdr->e_phnum; i++) {
+                  ElfXX_Phdr *o_phdr = &((ElfXX_Phdr *)(dimage + ehdr->e_phoff))[i];
+                  if (o_phdr->p_type == PT_LOAD) {
+                     offset_dimage = si->start - o_phdr->p_vaddr;
+                     break;
+                  }
+               }
+
+               debug_offset = offset_dimage;
+               if (need_symtab)
+                  o_symtab_offset = offset_dimage;
+
                shdr = (ElfXX_Shdr*)(dimage + ehdr->e_shoff);
                sh_strtab = (UChar*)(dimage + shdr[ehdr->e_shstrndx].sh_offset);
 
@@ -1122,8 +1143,9 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
                /* Find all interesting sections */
                for (i = 0; i < ehdr->e_shnum; i++) {
 
-#                 define FIND(sec_name, sec_size, sec_filea)   \
-                  if (0 == VG_(strcmp)(sec_name, sh_strtab + shdr[i].sh_name)) { \
+#                 define FIND(condition, sec_name, sec_size, sec_filea)        \
+                  if (condition \
+                      && 0 == VG_(strcmp)(sec_name, sh_strtab + shdr[i].sh_name)) { \
                      Bool nobits; \
                      if (0 != sec_filea) \
                         VG_(core_panic)("repeated section!\n"); \
@@ -1140,14 +1162,16 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
                      } \
                   }
 
-                  FIND(".stab",         stab_sz,         stab)
-                  FIND(".stabstr",      stabstr_sz,      stabstr)
-                  FIND(".debug_line",   debug_line_sz,   debug_line)
-                  FIND(".debug_info",   debug_info_sz,   debug_info)
-                  FIND(".debug_abbrev", debug_abbv_sz,   debug_abbv)
-                  FIND(".debug_str",    debug_str_sz,    debug_str)
-                  FIND(".debug",        dwarf1d_sz,      dwarf1d)
-                  FIND(".line",         dwarf1l_sz,      dwarf1l)
+                  FIND(need_symtab, ".symtab",       o_symtab_sz,   o_symtab)
+                  FIND(need_symtab, ".strtab",       o_strtab_sz,   o_strtab)
+                  FIND(1,           ".stab",         stab_sz,       stab)
+                  FIND(1,           ".stabstr",      stabstr_sz,    stabstr)
+                  FIND(1,           ".debug_line",   debug_line_sz, debug_line)
+                  FIND(1,           ".debug_info",   debug_info_sz, debug_info)
+                  FIND(1,           ".debug_abbrev", debug_abbv_sz, debug_abbv)
+                  FIND(1,           ".debug_str",    debug_str_sz,  debug_str)
+                  FIND(1,           ".debug",        dwarf1d_sz,    dwarf1d)
+                  FIND(1,           ".line",         dwarf1l_sz,    dwarf1l)
 
 #                 undef FIND
                }
@@ -1155,22 +1179,26 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
          }
       }
 
+      /* Check some sizes */
+      vg_assert((o_dynsym_sz % sizeof(ElfXX_Sym)) == 0);
+      vg_assert((o_symtab_sz % sizeof(ElfXX_Sym)) == 0);
+
       /* Read symbols */
       {
          void (*read_elf_symtab)(struct _SegInfo*,UChar*,ElfXX_Sym*,
-                                 UInt,UChar*,UInt,UChar*);
+                                 UInt,OffT,UChar*,UInt,UChar*,OffT);
 #        if defined(VGP_ppc64_linux)
          read_elf_symtab = read_elf_symtab__ppc64_linux;
 #        else
          read_elf_symtab = read_elf_symtab__normal;
 #        endif
          read_elf_symtab(si, "symbol table",
-                         o_symtab, o_symtab_sz,
-                         o_strtab, o_strtab_sz, opd_filea);
+                         o_symtab, o_symtab_sz, o_symtab_offset,
+                         o_strtab, o_strtab_sz, opd_filea, opd_offset);
 
          read_elf_symtab(si, "dynamic symbol table",
-                         o_dynsym, o_dynsym_sz,
-                         o_dynstr, o_dynstr_sz, opd_filea);
+                         o_dynsym, o_dynsym_sz, o_dynsym_offset,
+                         o_dynstr, o_dynstr_sz, opd_filea, opd_offset);
       }
 
       /* Read .eh_frame (call-frame-info) if any */
@@ -1183,7 +1211,7 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
          we ignore it. */
 #     if !defined(VGP_amd64_linux)
       if (stab && stabstr) {
-         ML_(read_debuginfo_stabs) ( si, stab, stab_sz, 
+         ML_(read_debuginfo_stabs) ( si, debug_offset, stab, stab_sz, 
                                          stabstr, stabstr_sz );
       }
 #     endif
@@ -1193,7 +1221,7 @@ Bool ML_(read_elf_debug_info) ( struct _SegInfo* si )
          read_unitinfo_dwarf2, do check that debugstr is non-NULL
          before using it. */
       if (debug_info && debug_abbv && debug_line /* && debug_str */) {
-         ML_(read_debuginfo_dwarf2) ( si, 
+         ML_(read_debuginfo_dwarf2) ( si, debug_offset, 
                                       debug_info,   debug_info_sz,
                                       debug_abbv,
                                       debug_line,   debug_line_sz,

diff --git a/coregrind/m_debuginfo/readstabs.c b/coregrind/m_debuginfo/readstabs.c
index b82a7d31de74bdb2d8269d47bc575a833fdc175b..1874cbd99c6e7e7c9443df4c2b32b37893953991 100644 (file)
--- a/coregrind/m_debuginfo/readstabs.c
+++ b/coregrind/m_debuginfo/readstabs.c
@@ -77,7 +77,7 @@ typedef enum { N_UNDEF = 0,   /* undefined symbol, new stringtab  */
 /* Read stabs-format debug info.  This is all rather horrible because
    stabs is a underspecified, kludgy hack.
 */
-void ML_(read_debuginfo_stabs) ( SegInfo* si,
+void ML_(read_debuginfo_stabs) ( SegInfo* si,    OffT debug_offset,
                                  UChar* stabC,   Int stab_sz, 
                                  UChar* stabstr, Int stabstr_sz )
 {
@@ -333,7 +333,7 @@ void ML_(read_debuginfo_stabs) ( SegInfo* si,
                line.first = True;
 
                /* line ends at start of next function */
-               addr = si->offset + st->n_value;
+               addr = debug_offset + st->n_value;
 
                func.start = addr;
             }