Re: RFC: fix bug when debugging prelink'd library

[Tom Tromey <tromey@redhat.com>]

Jan> Yes, I like the patch this way.

Great.

Jan> The same comment needs to be updated at the function definition in
Jan> dwarf2read.c.
[...]
Jan> Suggesting to extend the comment:
[...]

Here is what I am checking in.

Tom

2010-07-13  Tom Tromey  <tromey@redhat.com>

	* dwarf2loc.h (dwarf2_per_cu_text_offset): Declare.
	* dwarf2loc.c (find_location_expression): Use
	dwarf2_per_cu_text_offset.
	(dwarf2_evaluate_loc_desc): Likewise.
	(dwarf2_loc_desc_needs_frame): Likewise.
	(compile_dwarf_to_ax): Likewise.
	(loclist_describe_location): Likewise.
	* dwarf2read.c (dwarf2_per_cu_text_offset): New function.
	(dwarf2_per_cu_objfile): Update comment.

diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 4106b7f..2a8e557 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -70,8 +70,7 @@ find_location_expression (struct dwarf2_loclist_baton *baton,
   int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
   CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
   /* Adjust base_address for relocatable objects.  */
-  CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets,
-				    SECT_OFF_TEXT (objfile));
+  CORE_ADDR base_offset = dwarf2_per_cu_text_offset (baton->per_cu);
   CORE_ADDR base_address = baton->base_address + base_offset;
 
   loc_ptr = baton->data;
@@ -909,7 +908,7 @@ dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
 
   ctx->gdbarch = get_objfile_arch (objfile);
   ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
-  ctx->offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
+  ctx->offset = dwarf2_per_cu_text_offset (per_cu);
   ctx->baton = &baton;
   ctx->read_reg = dwarf_expr_read_reg;
   ctx->read_mem = dwarf_expr_read_mem;
@@ -1095,7 +1094,7 @@ dwarf2_loc_desc_needs_frame (const gdb_byte *data, unsigned short size,
 
   ctx->gdbarch = get_objfile_arch (objfile);
   ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
-  ctx->offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
+  ctx->offset = dwarf2_per_cu_text_offset (per_cu);
   ctx->baton = &baton;
   ctx->read_reg = needs_frame_read_reg;
   ctx->read_mem = needs_frame_read_mem;
@@ -1304,12 +1303,7 @@ compile_dwarf_to_ax (struct agent_expr *expr, struct axs_value *loc,
 	     index, not an address.  We don't support things like
 	     branching between the address and the TLS op.  */
 	  if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
-	    {
-	      struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
-
-	      uoffset += ANOFFSET (objfile->section_offsets,
-				   SECT_OFF_TEXT (objfile));
-	    }
+	    uoffset += dwarf2_per_cu_text_offset (per_cu);
 	  ax_const_l (expr, uoffset);
 	  break;
 
@@ -2511,8 +2505,7 @@ loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
   int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
   CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
   /* Adjust base_address for relocatable objects.  */
-  CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets,
-				    SECT_OFF_TEXT (objfile));
+  CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu);
   CORE_ADDR base_address = dlbaton->base_address + base_offset;
 
   loc_ptr = dlbaton->data;
diff --git a/gdb/dwarf2loc.h b/gdb/dwarf2loc.h
index 3ff595e..826bc45 100644
--- a/gdb/dwarf2loc.h
+++ b/gdb/dwarf2loc.h
@@ -28,7 +28,9 @@ struct dwarf2_per_cu_data;
 /* This header is private to the DWARF-2 reader.  It is shared between
    dwarf2read.c and dwarf2loc.c.  */
 
-/* Return the OBJFILE associated with the compilation unit CU.  */
+/* Return the OBJFILE associated with the compilation unit CU.  If CU
+   came from a separate debuginfo file, then the master objfile is
+   returned.  */
 struct objfile *dwarf2_per_cu_objfile (struct dwarf2_per_cu_data *cu);
 
 /* Return the address size given in the compilation unit header for CU.  */
@@ -37,6 +39,12 @@ CORE_ADDR dwarf2_per_cu_addr_size (struct dwarf2_per_cu_data *cu);
 /* Return the offset size given in the compilation unit header for CU.  */
 int dwarf2_per_cu_offset_size (struct dwarf2_per_cu_data *cu);
 
+/* Return the text offset of the CU.  The returned offset comes from
+   this CU's objfile.  If this objfile came from a separate debuginfo
+   file, then the offset may be different from the corresponding
+   offset in the parent objfile.  */
+CORE_ADDR dwarf2_per_cu_text_offset (struct dwarf2_per_cu_data *cu);
+
 struct dwarf2_locexpr_baton dwarf2_fetch_die_location_block
   (unsigned int offset, struct dwarf2_per_cu_data *per_cu);
 
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index e4ab034..16381de 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -12047,7 +12047,9 @@ dwarf2_symbol_mark_computed (struct attribute *attr, struct symbol *sym,
     }
 }
 
-/* Return the OBJFILE associated with the compilation unit CU.  */
+/* Return the OBJFILE associated with the compilation unit CU.  If CU
+   came from a separate debuginfo file, then the master objfile is
+   returned.  */
 
 struct objfile *
 dwarf2_per_cu_objfile (struct dwarf2_per_cu_data *per_cu)
@@ -12106,6 +12108,19 @@ dwarf2_per_cu_offset_size (struct dwarf2_per_cu_data *per_cu)
     }
 }
 
+/* Return the text offset of the CU.  The returned offset comes from
+   this CU's objfile.  If this objfile came from a separate debuginfo
+   file, then the offset may be different from the corresponding
+   offset in the parent objfile.  */
+
+CORE_ADDR
+dwarf2_per_cu_text_offset (struct dwarf2_per_cu_data *per_cu)
+{
+  struct objfile *objfile = per_cu->psymtab->objfile;
+
+  return ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
+}
+
 /* Locate the .debug_info compilation unit from CU's objfile which contains
    the DIE at OFFSET.  Raises an error on failure.  */