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From: manjian2006@gmail.com
To: gdb-patches@sourceware.org
Cc: linzj <linzj@ucweb.com>
Subject: [PATCH] fixed inherit_abstract_dies infinite recursive call
Date: Mon, 20 Jan 2014 06:22:00 -0000	[thread overview]
Message-ID: <1390198908-11691-1-git-send-email-manjian2006@gmail.com> (raw)

From: linzj <linzj@ucweb.com>

The c++ code causing the problem is:

    // Integer variants of certain metrics, used for HTML rendering.
    int ascent(FontBaseline baselineType = AlphabeticBaseline) const
    {
        if (baselineType == AlphabeticBaseline)
            return lroundf(m_ascent);
        return height() - height() / 2;
    }

    int height(FontBaseline baselineType = AlphabeticBaseline) const
    {
        return ascent(baselineType) + descent(baselineType);
    }

As you can see,ascent(0x5816d55) calls height(0x5812c1b),and height calls
ascent(0x5816d55) recursivly.And the compiler  generates these dwarf code
representing this relationship preciously.

A dwarf die may have the following relationship:
564860c<-----------------------------
  |                                 |
  |(abstract origin)                |
  |                                 |
  V                                 |
5816d55                             | (abstract origin)
  |                                 |
  |(child)                          |
  |                                 |
  V                                 |
  ...                               |
5812c34------------------------------
So inherit_abstract_dies may results in infinite recursive call.
A bit field call in_process has been add to struct die_info to fix this problem.
process_die would first check if a die is in processing state, if so,just return.
Then in_process bit is set.Before process_die returns,this bit field is unset.
---
 gdb/dwarf2read.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 7ca527d..c226a52 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -1224,6 +1224,8 @@ struct die_info
     /* True if we're presently building the full type name for the
        type derived from this DIE.  */
     unsigned char building_fullname : 1;
+    /* True if this die is in process.  */
+    unsigned char in_process : 1;
 
     /* Abbrev number */
     unsigned int abbrev;
@@ -8013,6 +8015,10 @@ process_imported_unit_die (struct die_info *die, struct dwarf2_cu *cu)
 static void
 process_die (struct die_info *die, struct dwarf2_cu *cu)
 {
+  /* Only process those who are not in process.  */
+  if (die->in_process)
+    return;
+  die->in_process = 1;
   switch (die->tag)
     {
     case DW_TAG_padding:
@@ -8100,6 +8106,7 @@ process_die (struct die_info *die, struct dwarf2_cu *cu)
       new_symbol (die, NULL, cu);
       break;
     }
+    die->in_process = 0;
 }
 \f
 /* DWARF name computation.  */
-- 
1.8.3.2


             reply	other threads:[~2014-01-20  6:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-20  6:22 manjian2006 [this message]
  -- strict thread matches above, loose matches on Subject: below --
2014-01-20  4:25 manjian2006
2014-01-20  5:53 ` Tom Tromey
2014-01-21  1:43   ` manjian2006
2014-01-21  7:54     ` Joel Brobecker
2014-01-20  6:30 ` manjian2006
2014-01-22  2:45   ` Doug Evans
2014-01-20  3:41 manjian2006

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