[v2,13/20] Change how reprocessing is done

Message ID 20200404144320.18851-14-tom@tromey.com
State New
Headers show
Series
  • Make DWARF attribute references safe
Related show

Commit Message

Tom Tromey April 4, 2020, 2:43 p.m.
Currently gdb keeps a vector of attributes that require reprocessing.
However, now that there is a reprocessing flag in the attribute, we
can remove the vector and instead simply loop over attributes a second
time.  Normally there are not many attributes, so this should be
reasonably cheap.

gdb/ChangeLog
2020-04-04  Tom Tromey  <tom@tromey.com>

	* dwarf2/read.c (skip_one_die): Update.
	(read_full_die_1): Change how reprocessing is done.
	(partial_die_info::read): Update.
	(read_attribute_value): Remove need_reprocess parameter.
	(read_attribute): Likewise.
	* dwarf2/attribute.h (struct attribute) <requires_reprocessing_p>:
	New method.
---
 gdb/ChangeLog          | 10 +++++++++
 gdb/dwarf2/attribute.h |  6 ++++++
 gdb/dwarf2/read.c      | 49 +++++++++++++++++++-----------------------
 3 files changed, 38 insertions(+), 27 deletions(-)

-- 
2.17.2

Patch

diff --git a/gdb/dwarf2/attribute.h b/gdb/dwarf2/attribute.h
index e2b06294490..63b9a761bf9 100644
--- a/gdb/dwarf2/attribute.h
+++ b/gdb/dwarf2/attribute.h
@@ -220,6 +220,12 @@  struct attribute
     requires_reprocessing = 0;
   }
 
+  /* True if this attribute requires reprocessing.  */
+  bool requires_reprocessing_p () const
+  {
+    return requires_reprocessing;
+  }
+
 
   ENUM_BITFIELD(dwarf_attribute) name : 15;
 
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 725a568c703..a3815a921c9 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -1192,7 +1192,7 @@  static const struct cu_partial_die_info find_partial_die (sect_offset, int,
 
 static const gdb_byte *read_attribute (const struct die_reader_specs *,
 				       struct attribute *, struct attr_abbrev *,
-				       const gdb_byte *, bool *need_reprocess);
+				       const gdb_byte *);
 
 static void read_attribute_reprocess (const struct die_reader_specs *reader,
 				      struct attribute *attr);
@@ -8492,9 +8492,7 @@  skip_one_die (const struct die_reader_specs *reader, const gdb_byte *info_ptr,
       /* The only abbrev we care about is DW_AT_sibling.  */
       if (abbrev->attrs[i].name == DW_AT_sibling)
 	{
-	  bool ignored;
-	  read_attribute (reader, &attr, &abbrev->attrs[i], info_ptr,
-			  &ignored);
+	  read_attribute (reader, &attr, &abbrev->attrs[i], info_ptr);
 	  if (attr.form == DW_FORM_ref_addr)
 	    complaint (_("ignoring absolute DW_AT_sibling"));
 	  else
@@ -17526,15 +17524,13 @@  read_full_die_1 (const struct die_reader_specs *reader,
      attributes.  */
   die->num_attrs = abbrev->num_attrs;
 
-  std::vector<int> indexes_that_need_reprocess;
+  bool any_need_reprocess = false;
   for (i = 0; i < abbrev->num_attrs; ++i)
     {
-      bool need_reprocess;
-      info_ptr =
-        read_attribute (reader, &die->attrs[i], &abbrev->attrs[i],
-			info_ptr, &need_reprocess);
-      if (need_reprocess)
-        indexes_that_need_reprocess.push_back (i);
+      info_ptr = read_attribute (reader, &die->attrs[i], &abbrev->attrs[i],
+				 info_ptr);
+      if (die->attrs[i].requires_reprocessing_p ())
+	any_need_reprocess = true;
     }
 
   struct attribute *attr = die->attr (DW_AT_str_offsets_base);
@@ -17544,8 +17540,14 @@  read_full_die_1 (const struct die_reader_specs *reader,
   auto maybe_addr_base = die->addr_base ();
   if (maybe_addr_base.has_value ())
     cu->addr_base = *maybe_addr_base;
-  for (int index : indexes_that_need_reprocess)
-    read_attribute_reprocess (reader, &die->attrs[index]);
+  if (any_need_reprocess)
+    {
+      for (i = 0; i < abbrev->num_attrs; ++i)
+	{
+	  if (die->attrs[i].requires_reprocessing_p ())
+	    read_attribute_reprocess (reader, &die->attrs[i]);
+	}
+    }
   *diep = die;
   return info_ptr;
 }
@@ -17899,13 +17901,11 @@  partial_die_info::read (const struct die_reader_specs *reader,
   for (i = 0; i < abbrev.num_attrs; ++i)
     {
       attribute attr;
-      bool need_reprocess;
-      info_ptr = read_attribute (reader, &attr, &abbrev.attrs[i],
-				 info_ptr, &need_reprocess);
+      info_ptr = read_attribute (reader, &attr, &abbrev.attrs[i], info_ptr);
       /* String and address offsets that need to do the reprocessing have
          already been read at this point, so there is no need to wait until
 	 the loop terminates to do the reprocessing.  */
-      if (need_reprocess)
+      if (attr.requires_reprocessing_p ())
 	read_attribute_reprocess (reader, &attr);
       /* Store the data if it is of an attribute we want to keep in a
          partial symbol table.  */
@@ -18385,8 +18385,7 @@  read_attribute_reprocess (const struct die_reader_specs *reader,
 static const gdb_byte *
 read_attribute_value (const struct die_reader_specs *reader,
 		      struct attribute *attr, unsigned form,
-		      LONGEST implicit_const, const gdb_byte *info_ptr,
-		      bool *need_reprocess)
+		      LONGEST implicit_const, const gdb_byte *info_ptr)
 {
   struct dwarf2_cu *cu = reader->cu;
   struct dwarf2_per_objfile *dwarf2_per_objfile
@@ -18397,7 +18396,6 @@  read_attribute_value (const struct die_reader_specs *reader,
   struct comp_unit_head *cu_header = &cu->header;
   unsigned int bytes_read;
   struct dwarf_block *blk;
-  *need_reprocess = false;
 
   attr->form = (enum dwarf_form) form;
   switch (form)
@@ -18574,14 +18572,13 @@  read_attribute_value (const struct die_reader_specs *reader,
 	  info_ptr += bytes_read;
 	}
       info_ptr = read_attribute_value (reader, attr, form, implicit_const,
-				       info_ptr, need_reprocess);
+				       info_ptr);
       break;
     case DW_FORM_implicit_const:
       attr->set_signed (implicit_const);
       break;
     case DW_FORM_addrx:
     case DW_FORM_GNU_addr_index:
-      *need_reprocess = true;
       attr->set_unsigned_reprocess (read_unsigned_leb128 (abfd, info_ptr,
 							  &bytes_read));
       info_ptr += bytes_read;
@@ -18619,9 +18616,8 @@  read_attribute_value (const struct die_reader_specs *reader,
 	    str_index = read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
 	    info_ptr += bytes_read;
 	  }
-	*need_reprocess = true;
 	attr->set_unsigned_reprocess (str_index);
-	}
+      }
       break;
     default:
       error (_("Dwarf Error: Cannot handle %s in DWARF reader [in module %s]"),
@@ -18657,14 +18653,13 @@  read_attribute_value (const struct die_reader_specs *reader,
 static const gdb_byte *
 read_attribute (const struct die_reader_specs *reader,
 		struct attribute *attr, struct attr_abbrev *abbrev,
-		const gdb_byte *info_ptr, bool *need_reprocess)
+		const gdb_byte *info_ptr)
 {
   attr->name = abbrev->name;
   attr->string_is_canonical = 0;
   attr->requires_reprocessing = 0;
   return read_attribute_value (reader, attr, abbrev->form,
-			       abbrev->implicit_const, info_ptr,
-			       need_reprocess);
+			       abbrev->implicit_const, info_ptr);
 }
 
 /* Return pointer to string at .debug_str offset STR_OFFSET.  */