Change libunwind-ptrace to also look for .debug_frame if nothing found in .eh_frame.

This changes the behavior of libunwind-ptrace to what we do for local
unwinding.

Signed-off-by: Ken Werner <ken.werner@linaro.org>

src/ptrace/_UPT_create.c

@@ -37,5 +37,10 @@ _UPT_create (pid_t pid)
 
   memset (ui, 0, sizeof (*ui));
   ui->pid = pid;
+  ui->di_cache.format = -1;
+  ui->di_debug.format = -1;
+#if UNW_TARGET_IA64
+  ui->ktab.format = -1;;
+#endif
   return ui;
 }

src/ptrace/_UPT_find_proc_info.c

@@ -164,7 +164,7 @@ dwarf_read_encoded_pointer (unw_addr_space_t as, unw_accessors_t *a,
 					     pi, valp, arg);
 }
 
-HIDDEN unw_dyn_info_t *
+HIDDEN int
 _UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
 			 char *path, unw_word_t segbase, unw_word_t mapoff,
 			 unw_word_t ip)
@@ -176,12 +176,12 @@ _UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
   unw_proc_info_t pi;
   unw_accessors_t *a;
   Elf_W(Ehdr) *ehdr;
-  int i, ret;
+  int i, ret, found = 0;
 
   /* XXX: Much of this code is Linux/LSB-specific.  */
 
   if (!elf_w(valid_object) (&ui->ei))
-    return NULL;
+    return -UNW_ENOINFO;
 
   ehdr = ui->ei.image;
   phdr = (Elf_W(Phdr) *) ((char *) ui->ei.image + ehdr->e_phoff);
@@ -209,37 +209,12 @@ _UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
 	  break;
 	}
     }
-  if (!ptxt || !peh_hdr)
+
-#ifdef CONFIG_DEBUG_FRAME
+  if (!ptxt)
+    return 0;
+
+  if (peh_hdr)
     {
-      /* No .eh_frame found, try .debug_frame. */
-      struct dl_phdr_info info;
-
-      info.dlpi_name = path;
-      info.dlpi_phdr = phdr;
-      info.dlpi_phnum = ehdr->e_phnum;
-
-      /* Fixup segbase to match correct base address. */
-      for (i = 0; i < info.dlpi_phnum; i++)
-       {
-         if (info.dlpi_phdr[i].p_type == PT_LOAD &&
-           info.dlpi_phdr[i].p_offset == 0)
-             {
-               segbase -= info.dlpi_phdr[i].p_vaddr;
-               break;
-             }
-       }
-      info.dlpi_addr = segbase;
-
-      if (dwarf_find_debug_frame (0, &ui->di_cache, &info, ip))
-       return &ui->di_cache;
-      else
-       return NULL;
-    }
-#else
-    return NULL;
-#endif
-
       if (pdyn)
 	{
 	  /* For dynamicly linked executables and shared libraries,
@@ -268,7 +243,7 @@ _UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
 	{
 	  Debug (1, "table `%s' has unexpected version %d\n",
 		 path, hdr->version);
-      return 0;
+	  return -UNW_ENOINFO;
 	}
 
       a = unw_get_accessors (unw_local_addr_space);
@@ -285,19 +260,19 @@ _UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
       if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a,
 					     &addr, hdr->eh_frame_ptr_enc, &pi,
 					     &eh_frame_start, NULL)) < 0)
-    return NULL;
+	return -UNW_ENOINFO;
 
       /* (Optionally) read fde_count: */
       if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a,
 					     &addr, hdr->fde_count_enc, &pi,
 					     &fde_count, NULL)) < 0)
-    return NULL;
+	return -UNW_ENOINFO;
 
       if (hdr->table_enc != (DW_EH_PE_datarel | DW_EH_PE_sdata4))
 	{
-#if 1
+    #if 1
 	  abort ();
-#else
+    #else
 	  unw_word_t eh_frame_end;
 
 	  /* If there is no search table or it has an unsupported
@@ -318,7 +293,7 @@ _UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
 	  return linear_search (unw_local_addr_space, ip,
 				eh_frame_start, eh_frame_end, fde_count,
 				pi, need_unwind_info, NULL);
-#endif
+    #endif
 	}
 
       load_base = segbase - ptxt->p_vaddr;
@@ -338,29 +313,58 @@ _UPTi_find_unwind_table (struct UPT_info *ui, unw_addr_space_t as,
       ui->di_cache.u.rti.segbase = ((load_base + peh_hdr->p_vaddr)
 				    + ((unw_word_t) hdr - (unw_word_t) ui->ei.image
 				       - peh_hdr->p_offset));
+      found = 1;
+    }
 
-  return &ui->di_cache;
+#ifdef CONFIG_DEBUG_FRAME
+  {
+      /* Try .debug_frame. */
+      struct dl_phdr_info info;
+
+      info.dlpi_name = path;
+      info.dlpi_phdr = phdr;
+      info.dlpi_phnum = ehdr->e_phnum;
+
+      /* Fixup segbase to match correct base address. */
+      for (i = 0; i < info.dlpi_phnum; i++)
+       {
+         if (info.dlpi_phdr[i].p_type == PT_LOAD &&
+           info.dlpi_phdr[i].p_offset == 0)
+             {
+               segbase -= info.dlpi_phdr[i].p_vaddr;
+               break;
+             }
+       }
+      info.dlpi_addr = segbase;
+
+      found = dwarf_find_debug_frame (found, &ui->di_debug, &info, ip);
+  }
+#endif
+
+  return found;
 }
 
 #endif /* UNW_TARGET_X86 || UNW_TARGET_X86_64 || UNW_TARGET_HPPA*/
 
-static unw_dyn_info_t *
+static int
 get_unwind_info (struct UPT_info *ui, unw_addr_space_t as, unw_word_t ip)
 {
   unsigned long segbase, mapoff;
   char path[PATH_MAX];
-  unw_dyn_info_t *di;
 
 #if UNW_TARGET_IA64 && defined(__linux)
   if (!ui->ktab.start_ip && _Uia64_get_kernel_table (&ui->ktab) < 0)
-    return NULL;
+    return -UNW_ENOINFO;
 
-  if (ip >= ui->ktab.start_ip && ip < ui->ktab.end_ip)
+  if (ui->ktab.format != -1 && ip >= ui->ktab.start_ip && ip < ui->ktab.end_ip)
-    return &ui->ktab;
+    return 0;
 #endif
 
-  if (ip >= ui->di_cache.start_ip && ip < ui->di_cache.end_ip)
+  if ((ui->di_cache.format != -1
-    return &ui->di_cache;
+       && ip >= ui->di_cache.start_ip && ip < ui->di_cache.end_ip)
+      || (ui->di_debug.format != -1
+       && ip >= ui->di_debug.start_ip && ip < ui->di_debug.end_ip))
+    return 0;
 
   if (ui->ei.image)
     {
@@ -370,24 +374,36 @@ get_unwind_info (struct UPT_info *ui, unw_addr_space_t as, unw_word_t ip)
 
       /* invalidate the cache: */
       ui->di_cache.start_ip = ui->di_cache.end_ip = 0;
+      ui->di_debug.start_ip = ui->di_debug.end_ip = 0;
+      ui->di_cache.format = -1;
+      ui->di_debug.format = -1;
     }
 
   if (tdep_get_elf_image (&ui->ei, ui->pid, ip, &segbase, &mapoff, path,
                           sizeof(path)) < 0)
-    return NULL;
+    return -UNW_ENOINFO;
 
   /* Here, SEGBASE is the starting-address of the (mmap'ped) segment
      which covers the IP we're looking for.  */
-  di = _UPTi_find_unwind_table (ui, as, path, segbase, mapoff, ip);
+  if (_UPTi_find_unwind_table (ui, as, path, segbase, mapoff, ip) < 0)
-  if (!di
+    return -UNW_ENOINFO;
+
   /* This can happen in corner cases where dynamically generated
      code falls into the same page that contains the data-segment
      and the page-offset of the code is within the first page of
      the executable.  */
-      || ip < di->start_ip || ip >= di->end_ip)
+  if (ui->di_cache.format != -1
-    return NULL;
+      && (ip < ui->di_cache.start_ip || ip >= ui->di_cache.end_ip))
+     ui->di_cache.format = -1;
 
-  return di;
+  if (ui->di_debug.format != -1
+      && (ip < ui->di_debug.start_ip || ip >= ui->di_debug.end_ip))
+     ui->di_debug.format = -1;
+
+  if (ui->di_cache.format == -1 && ui->di_debug.format == -1)
+    return -UNW_ENOINFO;
+
+  return 0;
 }
 
 int
@@ -395,14 +411,13 @@ _UPT_find_proc_info (unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
 		     int need_unwind_info, void *arg)
 {
   struct UPT_info *ui = arg;
-  unw_dyn_info_t *di;
+  int ret = -UNW_ENOINFO;
 
-  di = get_unwind_info (ui, as, ip);
+  if (get_unwind_info (ui, as, ip) < 0)
-  if (!di)
     return -UNW_ENOINFO;
 
 #if UNW_TARGET_IA64
-  if (di == &ui->ktab)
+  if (ui->ktab.format != -1)
     {
       /* The kernel unwind table resides in local memory, so we have
 	 to use the local address space to search it.  Since
@@ -410,7 +425,7 @@ _UPT_find_proc_info (unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
 	 case, we simply make a copy of the unwind-info, so
 	 _UPT_put_unwind_info() can always free() the unwind-info
 	 without ill effects.  */
-      int ret = tdep_search_unwind_table (unw_local_addr_space, ip, di, pi,
+      ret = tdep_search_unwind_table (unw_local_addr_space, ip, &ui->ktab, pi,
 				      need_unwind_info, arg);
       if (ret >= 0)
 	{
@@ -426,9 +441,16 @@ _UPT_find_proc_info (unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
 	      pi->unwind_info = mem;
 	    }
 	}
-      return ret;
     }
-  else
 #endif
-  return tdep_search_unwind_table (as, ip, di, pi, need_unwind_info, arg);
+
+  if (ret == -UNW_ENOINFO && ui->di_cache.format == -1)
+    ret = tdep_search_unwind_table (as, ip, &ui->di_cache,
+				    pi, need_unwind_info, arg);
+
+  if (ret == -UNW_ENOINFO && ui->di_debug.format != -1)
+    ret = tdep_search_unwind_table (as, ip, &ui->di_debug, pi,
+				    need_unwind_info, arg);
+
+  return ret;
 }

src/ptrace/_UPT_internal.h

@@ -53,6 +53,7 @@ struct UPT_info
     pid_t pid;		/* the process-id of the child we're unwinding */
     struct elf_image ei;
     unw_dyn_info_t di_cache;
+    unw_dyn_info_t di_debug;	/* additional table info for .debug_frame */
 #if UNW_TARGET_IA64
     unw_dyn_info_t ktab;
 #endif
@@ -60,7 +61,7 @@ struct UPT_info
 
 extern int _UPT_reg_offset[UNW_REG_LAST + 1];
 
-extern unw_dyn_info_t *_UPTi_find_unwind_table (struct UPT_info *ui,
+extern int _UPTi_find_unwind_table (struct UPT_info *ui,
 				    unw_addr_space_t as,
 				    char *path,
 				    unw_word_t segbase,