Re: [patch] Add debug_frame parsing

[Mark Wielaard <mark@klomp.org>]

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Hi,

On Thu, 2008-01-17 at 12:12 +0100, Mark Wielaard wrote:
> Although it does find the right fde covering the ip ranges, it doesn't
> always run the cfi program correctly.

Because it was using the wrong address space... duh.
So this small patch records and makes sure the right one is always used
(debug_frame lives in our, not in the inferior address space).

frysk-imports/libunwind/ChangeLog
2008-01-18  Mark Wielaard  <mwielaard@redhat.com>
    
       * include/dwarf.h (dwarf_cie_info): Add as and as_arg members.
       * src/dwarf/Gfde.c (dwarf_extract_proc_info_from_fde): Set dci
       as and as_arg when not local only.
       * src/dwarf/Gparser.c (run_cfi_program): Use dci as and as_arg
       when not local only.
    
frysk-sys/lib/unwind/ChangeLog
2008-01-18  Mark Wielaard  <mwielaard@redhat.com>
    
       * cni/UnwindH.hxx (get_eh_frame_hdr_addr): Prefer debug_frame.

The patch is small, but it does enable using debug_frame in preference
to eh_frame when found (but currently only in the main executable, a
follow up patch should make sure that libdwfl is always used to get at
the debug_frame). All tests now PASS with this enabled.

Cheers,

Mark

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diff --git a/frysk-imports/libunwind/include/dwarf.h b/frysk-imports/libunwind/include/dwarf.h
index cf8a74a..3a17c87 100644
--- a/frysk-imports/libunwind/include/dwarf.h
+++ b/frysk-imports/libunwind/include/dwarf.h
@@ -252,6 +252,10 @@ dwarf_reg_state_t;
 
 typedef struct dwarf_cie_info
   {
+#ifndef UNW_LOCAL_ONLY
+    unw_addr_space_t as;        /* reference to frame address-space */
+    void *as_arg;               /* argument to address-space callbacks */
+#endif
     unw_word_t cie_instr_start;	/* start addr. of CIE "initial_instructions" */
     unw_word_t cie_instr_end;	/* end addr. of CIE "initial_instructions" */
     unw_word_t fde_instr_start;	/* start addr. of FDE "instructions" */
diff --git a/frysk-imports/libunwind/src/dwarf/Gfde.c b/frysk-imports/libunwind/src/dwarf/Gfde.c
index de2b193..a9c36f4 100644
--- a/frysk-imports/libunwind/src/dwarf/Gfde.c
+++ b/frysk-imports/libunwind/src/dwarf/Gfde.c
@@ -351,7 +351,10 @@ dwarf_extract_proc_info_from_fde (unw_addr_space_t as, unw_accessors_t *a,
       else
 	dci.fde_instr_start = addr;
       dci.fde_instr_end = fde_end_addr;
-
+#ifndef UNW_LOCAL_ONLY
+      dci.as = as;
+      dci.as_arg = arg;
+#endif
       memcpy (pi->unwind_info, &dci, sizeof (dci));
     }
   return 0;
diff --git a/frysk-imports/libunwind/src/dwarf/Gparser.c b/frysk-imports/libunwind/src/dwarf/Gparser.c
index ada82d9..441cf9b 100644
--- a/frysk-imports/libunwind/src/dwarf/Gparser.c
+++ b/frysk-imports/libunwind/src/dwarf/Gparser.c
@@ -71,8 +71,13 @@ run_cfi_program (struct dwarf_cursor *c, dwarf_state_record_t *sr,
   void *arg;
   int ret;
 
+#ifndef UNW_LOCAL_ONLY
+  as = dci->as;
+  arg = dci->as_arg;
+#else
   as = c->as;
   arg = c->as_arg;
+#endif
   a = unw_get_accessors (as);
   curr_ip = c->pi.start_ip;
 
diff --git a/frysk-sys/lib/unwind/cni/UnwindH.hxx b/frysk-sys/lib/unwind/cni/UnwindH.hxx
index 08c8ce1..f56d16b 100644
--- a/frysk-sys/lib/unwind/cni/UnwindH.hxx
+++ b/frysk-sys/lib/unwind/cni/UnwindH.hxx
@@ -567,11 +567,7 @@ get_eh_frame_hdr_addr(unw_proc_info_t *pi, char *image, size_t size,
   *peh_vaddr = peh_hdr.p_vaddr;
 
   char *hdr;
-  // FIXME. Currently we prefer eh_frame, but we should switch to
-  // prefer debug_frame when all bugs have been squashed out of that
-  // in libunwind.
-  if (peh_hdr_ndx == -1
-      && debug_frame_data != NULL && debug_frame_data->d_buf != NULL
+  if (debug_frame_data != NULL && debug_frame_data->d_buf != NULL
       && debug_frame_data->d_size != 0)
     {
       pi->format = UNW_INFO_FORMAT_TABLE;