libdw: Recognize .debug_[ct]u_index sections in dwarf_elf_begin

DWARF package (.dwp) files have a .debug_cu_index section and,
optionally, a .debug_tu_index section.  Add them to the list of DWARF
sections.

Unfortunately, it's not that simple: the other debug sections in a dwp
file have names ending with .dwo, which confuses the checks introduced
by commit 5b21e70216b8 ("libdw: dwarf_elf_begin should use either plain,
dwo or lto DWARF sections.").  So, we also have to special case
.debug_cu_index and .debug_tu_index in scn_dwarf_type and check_section
to treat them as TYPE_DWO sections.

Signed-off-by: Omar Sandoval <osandov@fb.com>

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index be1e40bc190d50147d5aa46b1d3301cc7caff6f0..52327688451604c3279000debeffebbc86259fcd 100644 (file)
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -20,6 +20,14 @@
        instead of dbg parameter, which is now unused.
        * libdwP.h (Dwarf_Macro_Op_Table): Replace is_64bit with address_size
        and offset_size.  Add dbg.
+       Add IDX_debug_cu_index and IDX_debug_tu_index.
+       * dwarf_begin_elf.c (dwarf_scnnames): Add IDX_debug_cu_index and
+       IDX_debug_tu_index.
+       (scn_to_string_section_idx): Ditto.
+       (scn_dwarf_type): Check for .debug_cu_index, .debug_tu_index,
+       .zdebug_cu_index, and .zdebug_tu_index.
+       (check_section): Change .dwo suffix matching to account for
+       .debug_cu_index and .debug_tu_index.
 
 2023-02-22  Mark Wielaard  <mark@klomp.org>
 

diff --git a/libdw/dwarf_begin_elf.c b/libdw/dwarf_begin_elf.c
index 92d76d240585e4a9ef16674fe5fbdcc7ac53b97b..7936d343219fe226dd55f169d5822307c63b3a6a 100644 (file)
--- a/libdw/dwarf_begin_elf.c
+++ b/libdw/dwarf_begin_elf.c
@@ -67,6 +67,8 @@ static const char dwarf_scnnames[IDX_last][19] =
   [IDX_debug_macro] = ".debug_macro",
   [IDX_debug_ranges] = ".debug_ranges",
   [IDX_debug_rnglists] = ".debug_rnglists",
+  [IDX_debug_cu_index] = ".debug_cu_index",
+  [IDX_debug_tu_index] = ".debug_tu_index",
   [IDX_gnu_debugaltlink] = ".gnu_debugaltlink"
 };
 #define ndwarf_scnnames (sizeof (dwarf_scnnames) / sizeof (dwarf_scnnames[0]))
@@ -92,6 +94,8 @@ static const enum string_section_index scn_to_string_section_idx[IDX_last] =
   [IDX_debug_macro] = STR_SCN_IDX_last,
   [IDX_debug_ranges] = STR_SCN_IDX_last,
   [IDX_debug_rnglists] = STR_SCN_IDX_last,
+  [IDX_debug_cu_index] = STR_SCN_IDX_last,
+  [IDX_debug_tu_index] = STR_SCN_IDX_last,
   [IDX_gnu_debugaltlink] = STR_SCN_IDX_last
 };
 
@@ -109,6 +113,11 @@ scn_dwarf_type (Dwarf *result, size_t shstrndx, Elf_Scn *scn)
     {
       if (startswith (scnname, ".gnu.debuglto_.debug"))
        return TYPE_GNU_LTO;
+      else if (strcmp (scnname, ".debug_cu_index") == 0
+              || strcmp (scnname, ".debug_tu_index") == 0
+              || strcmp (scnname, ".zdebug_cu_index") == 0
+              || strcmp (scnname, ".zdebug_tu_index") == 0)
+       return TYPE_DWO;
       else if (startswith (scnname, ".debug_") || startswith (scnname, ".zdebug_"))
        {
          size_t len = strlen (scnname);
@@ -173,42 +182,34 @@ check_section (Dwarf *result, size_t shstrndx, Elf_Scn *scn, bool inscngrp)
   bool gnu_compressed = false;
   for (cnt = 0; cnt < ndwarf_scnnames; ++cnt)
     {
+      /* .debug_cu_index and .debug_tu_index don't have a .dwo suffix,
+        but they are for DWO.  */
+      if (result->type != TYPE_DWO
+         && (cnt == IDX_debug_cu_index || cnt == IDX_debug_tu_index))
+       continue;
+      bool need_dot_dwo =
+       (result->type == TYPE_DWO
+        && cnt != IDX_debug_cu_index
+        && cnt != IDX_debug_tu_index);
       size_t dbglen = strlen (dwarf_scnnames[cnt]);
       size_t scnlen = strlen (scnname);
       if (strncmp (scnname, dwarf_scnnames[cnt], dbglen) == 0
-         && (dbglen == scnlen
-             || (scnlen == dbglen + 4
+         && ((!need_dot_dwo && dbglen == scnlen)
+             || (need_dot_dwo
+                 && scnlen == dbglen + 4
                  && strstr (scnname, ".dwo") == scnname + dbglen)))
-       {
-         if (dbglen == scnlen)
-           {
-             if (result->type == TYPE_PLAIN)
-               break;
-           }
-         else if (result->type == TYPE_DWO)
-           break;
-       }
+       break;
       else if (scnname[0] == '.' && scnname[1] == 'z'
               && (strncmp (&scnname[2], &dwarf_scnnames[cnt][1],
                            dbglen - 1) == 0
-                  && (scnlen == dbglen + 1
-                      || (scnlen == dbglen + 5
+                  && ((!need_dot_dwo && scnlen == dbglen + 1)
+                      || (need_dot_dwo
+                          && scnlen == dbglen + 5
                           && strstr (scnname,
                                      ".dwo") == scnname + dbglen + 1))))
        {
-         if (scnlen == dbglen + 1)
-           {
-             if (result->type == TYPE_PLAIN)
-               {
-                 gnu_compressed = true;
-                 break;
-               }
-           }
-         else if (result->type <= TYPE_DWO)
-           {
-             gnu_compressed = true;
-             break;
-           }
+         gnu_compressed = true;
+         break;
        }
       else if (scnlen > 14 /* .gnu.debuglto_ prefix. */
               && startswith (scnname, ".gnu.debuglto_")

diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index 77959b3bd3d68e168c2739a7afbbbe988708aee0..0c44d40c910a1865811c69fcb7bec3c880dd9032 100644 (file)
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -82,6 +82,8 @@ enum
     IDX_debug_macro,
     IDX_debug_ranges,
     IDX_debug_rnglists,
+    IDX_debug_cu_index,
+    IDX_debug_tu_index,
     IDX_gnu_debugaltlink,
     IDX_last
   };