Add validity bits for psymtab high and low fields

Right now some psymtab code checks whether a psymtab's textlow or
texthigh fields are valid by comparing against 0.

I imagine this is mildly wrong in the current environment, but once
psymtabs are relocated dynamically, it will no longer be correct,
because it will be much more normal to see a psymtab with a textlow of
zero -- this will just mean it appears at the start of the text
section.

This patch introduces validity bits to handle this situation more
nicely, and changes users of the code to follow.

gdb/ChangeLog
2018-07-26  Tom Tromey  <tromey@redhat.com>

	* dbxread.c (end_psymtab): Use text_high_valid and
	text_low_valid.
	* mdebugread.c (parse_partial_symbols): Use text_low_valid.
	(psymtab_to_symtab_1): Use text_high_valid and text_low_valid.
	* psympriv.h (struct partial_symtab) <m_text_low, m_text_high>:
	Update comment.
	<text_low_valid, text_high_valid>: New fields.
	<set_text_low, set_text_high>: Update.
	* xcoffread.c (scan_xcoff_symtab): Use text_low_valid.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e6972c29505ab845dc192e80d854f83dd40b8db0..b4ab4ff63604779ce72f5ee66e9e059fbbbaea7c 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,15 @@
+2018-07-26  Tom Tromey  <tromey@redhat.com>
+
+       * dbxread.c (end_psymtab): Use text_high_valid and
+       text_low_valid.
+       * mdebugread.c (parse_partial_symbols): Use text_low_valid.
+       (psymtab_to_symtab_1): Use text_high_valid and text_low_valid.
+       * psympriv.h (struct partial_symtab) <m_text_low, m_text_high>:
+       Update comment.
+       <text_low_valid, text_high_valid>: New fields.
+       <set_text_low, set_text_high>: Update.
+       * xcoffread.c (scan_xcoff_symtab): Use text_low_valid.
+
 2018-07-26  Tom Tromey  <tom@tromey.com>
 
        * dbxread.c (read_dbx_symtab, end_psymtab, read_ofile_symtab):

diff --git a/gdb/dbxread.c b/gdb/dbxread.c
index d5d4e083c5a6383c82361bfabbb9eca422da3ada..5409a727467756048aa4580dd6212698578fb873 100644 (file)
--- a/gdb/dbxread.c
+++ b/gdb/dbxread.c
@@ -2002,7 +2002,7 @@ dbx_end_psymtab (struct objfile *objfile, struct partial_symtab *pst,
      a reliable texthigh by taking the address plus size of the
      last function in the file.  */
 
-  if (pst->text_high () == 0 && last_function_name
+  if (!pst->text_high_valid && last_function_name
       && gdbarch_sofun_address_maybe_missing (gdbarch))
     {
       int n;
@@ -2047,13 +2047,11 @@ dbx_end_psymtab (struct objfile *objfile, struct partial_symtab *pst,
       /* If we know our own starting text address, then walk through all other
          psymtabs for this objfile, and if any didn't know their ending text
          address, set it to our starting address.  Take care to not set our
-         own ending address to our starting address, nor to set addresses on
-         `dependency' files that have both textlow and texthigh zero.  */
+         own ending address to our starting address.  */
 
       ALL_OBJFILE_PSYMTABS (objfile, p1)
       {
-       if (p1->text_high () == 0 && p1->text_low () != 0
-           && p1 != pst)
+       if (!p1->text_high_valid && p1->text_low_valid && p1 != pst)
          p1->set_text_high (pst->text_low ());
       }
     }

diff --git a/gdb/mdebugread.c b/gdb/mdebugread.c
index 262c619d4019b535f16ea81fddb34f3c09e417e7..436ef95dd3211143b5d834399dbdf273cee4a132 100644 (file)
--- a/gdb/mdebugread.c
+++ b/gdb/mdebugread.c
@@ -2736,7 +2736,7 @@ parse_partial_symbols (minimal_symbol_reader &reader,
 
                          /* Kludge for Irix 5.2 zero fh->adr.  */
                          if (!relocatable
-                             && (pst->text_low () == 0
+                             && (!pst->text_low_valid
                                  || procaddr < pst->text_low ()))
                            pst->set_text_low (procaddr);
                          if (high > pst->text_high ())
@@ -3512,7 +3512,7 @@ parse_partial_symbols (minimal_symbol_reader &reader,
 
                  /* Kludge for Irix 5.2 zero fh->adr.  */
                  if (!relocatable
-                     && (pst->text_low () == 0
+                     && (!pst->text_low_valid
                          || procaddr < pst->text_low ()))
                    pst->set_text_low (procaddr);
 
@@ -3711,7 +3711,7 @@ parse_partial_symbols (minimal_symbol_reader &reader,
          other cases.  */
       save_pst = fdr_to_pst[f_idx].pst;
       if (save_pst != NULL
-         && save_pst->text_low () != 0
+         && save_pst->text_low_valid
          && !(objfile->flags & OBJF_REORDERED))
        {
          ALL_OBJFILE_PSYMTABS (objfile, pst)
@@ -3922,7 +3922,7 @@ psymtab_to_symtab_1 (struct objfile *objfile,
   /* Do nothing if this is a dummy psymtab.  */
 
   if (pst->n_global_syms == 0 && pst->n_static_syms == 0
-      && pst->text_low () == 0 && pst->text_high () == 0)
+      && !pst->text_low_valid && !pst->text_high_valid)
     return;
 
   /* Now read the symbols for this symtab.  */

diff --git a/gdb/psympriv.h b/gdb/psympriv.h
index 7116a1a59579f21730a0138dff303a2acaf545a7..b3bda82b7b3c2c89c23870eb7c0e5138bdaa5d57 100644 (file)
--- a/gdb/psympriv.h
+++ b/gdb/psympriv.h
@@ -114,12 +114,14 @@ struct partial_symtab
   void set_text_low (CORE_ADDR addr)
   {
     m_text_low = addr;
+    text_low_valid = 1;
   }
 
   /* Set the hight text address of this partial_symtab.  */
   void set_text_high (CORE_ADDR addr)
   {
     m_text_high = addr;
+    text_high_valid = 1;
   }
 
 
@@ -144,7 +146,9 @@ struct partial_symtab
   /* Range of text addresses covered by this file; texthigh is the
      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
      is set.  Do not refer directly to these fields.  Instead, use the
-     accessors.  */
+     accessors.  The validity of these fields is determined by the
+     text_low_valid and text_high_valid fields; these are located later
+     in this structure for better packing.  */
 
   CORE_ADDR m_text_low;
   CORE_ADDR m_text_high;
@@ -230,6 +234,11 @@ struct partial_symtab
 
   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 
+  /* Validity of the m_text_low and m_text_high fields.  */
+
+  unsigned int text_low_valid : 1;
+  unsigned int text_high_valid : 1;
+
   /* Pointer to compunit eventually allocated for this source file, 0 if
      !readin or if we haven't looked for the symtab after it was readin.  */
 

diff --git a/gdb/xcoffread.c b/gdb/xcoffread.c
index 1aa2e523db26d5ebd2b8af228560b85966fdb9e4..7ca4b3ef3b26e25fbca43bfd2095677a822e6aee 100644 (file)
--- a/gdb/xcoffread.c
+++ b/gdb/xcoffread.c
@@ -2344,7 +2344,7 @@ scan_xcoff_symtab (minimal_symbol_reader &reader,
 
                        if (highval > pst->text_high ())
                          pst->set_text_high (highval);
-                       if (pst->text_low () == 0
+                       if (!pst->text_low_valid
                            || symbol.n_value < pst->text_low ())
                          pst->set_text_low (symbol.n_value);
                      }