[patch] fix unwind handling on hppa elf targets

[Randolph Chung <randolph at tausq dot org>]

This patch adds some infrastructure to make the generic hppa-tdep code
more sharable with hppa-linux. The unwind offset calculation is
applicable to all hppa-elf targets and not only on 64-bit targets. 

2004-04-10  Randolph Chung  <tausq@debian.org>

	* hppa-tdep.h (gdbarch_tdep): Add is_elf flag.
	* hppa-hpux-tdep.c (hppa_hpux_elf_init_abi): Set is_elf flag.
	* hppa-tdep.c (record_text_segment_lowaddr): Calculate text segment
	address using file offset.
	(internalize_unwinds): Predicate unwind offset calculation on is_elf
	flag rather than on width of binary. Remove "hokey" text segment
	masking (it is indeed wrong).

Index: hppa-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.h,v
retrieving revision 1.1
diff -u -p -r1.1 hppa-tdep.h
--- hppa-tdep.h	15 Aug 2003 23:02:03 -0000	1.1
+++ hppa-tdep.h	10 Apr 2004 08:50:20 -0000
@@ -21,10 +21,13 @@
 #ifndef HPPA_TDEP_H
 #define HPPA_TDEP_H
 
 /* Target-dependent structure in gdbarch.  */
 struct gdbarch_tdep
 {
   /* The number of bytes in an address.  For now, this field is designed
      to allow us to differentiate hppa32 from hppa64 targets.  */
   int bytes_per_address;
+
+  /* Is this an ELF target? This can be 64-bit HP-UX, or 32/64-bit Linux */
+  int is_elf;
 };
Index: hppa-hpux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-hpux-tdep.c,v
retrieving revision 1.14
diff -u -p -r1.14 hppa-hpux-tdep.c
--- hppa-hpux-tdep.c	8 Apr 2004 21:18:12 -0000	1.14
+++ hppa-hpux-tdep.c	10 Apr 2004 08:50:20 -0000
@@ -727,6 +727,9 @@ hppa_hpux_som_init_abi (struct gdbarch_i
 static void
 hppa_hpux_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  tdep->is_elf = 1;
   hppa_hpux_init_abi (info, gdbarch);
 }
 
Index: hppa-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.c,v
retrieving revision 1.142
diff -u -p -r1.142 hppa-tdep.c
--- hppa-tdep.c	6 Apr 2004 16:11:02 -0000	1.142
+++ hppa-tdep.c	10 Apr 2004 08:50:20 -0000
@@ -360,10 +360,14 @@ static CORE_ADDR low_text_segment_addres
 static void
 record_text_segment_lowaddr (bfd *abfd, asection *section, void *ignored)
 {
-  if (((section->flags & (SEC_ALLOC | SEC_LOAD | SEC_READONLY))
+  if ((section->flags & (SEC_ALLOC | SEC_LOAD | SEC_READONLY))
        == (SEC_ALLOC | SEC_LOAD | SEC_READONLY))
-      && section->vma < low_text_segment_address)
-    low_text_segment_address = section->vma;
+    {
+      bfd_vma value = section->vma - section->filepos;
+
+      if (value < low_text_segment_address)
+          low_text_segment_address = value;
+    }
 }
 
 static void
@@ -381,22 +385,18 @@ internalize_unwinds (struct objfile *obj
 
       low_text_segment_address = -1;
 
-      /* If addresses are 64 bits wide, then unwinds are supposed to
+      /* For ELF targets, then unwinds are supposed to
 	 be segment relative offsets instead of absolute addresses. 
 
 	 Note that when loading a shared library (text_offset != 0) the
 	 unwinds are already relative to the text_offset that will be
 	 passed in.  */
-      if (TARGET_PTR_BIT == 64 && text_offset == 0)
+      if (gdbarch_tdep (current_gdbarch)->is_elf && text_offset == 0)
 	{
 	  bfd_map_over_sections (objfile->obfd,
 				 record_text_segment_lowaddr, NULL);
 
-	  /* ?!? Mask off some low bits.  Should this instead subtract
-	     out the lowest section's filepos or something like that?
-	     This looks very hokey to me.  */
-	  low_text_segment_address &= ~0xfff;
-	  text_offset += low_text_segment_address;
+	  text_offset = low_text_segment_address;
 	}
 
       bfd_get_section_contents (objfile->obfd, section, buf, 0, size);
-- 
Randolph Chung
Debian GNU/Linux Developer, hppa/ia64 ports
http://www.tausq.org/