commit 58d9ce4730d95103c9388be264a170ab852432a9
Author: mjw <mjw@a5019735-40e9-0310-863c-91ae7b9d1cf9>
Date: Thu Apr 11 17:55:39 2013 +0000
read_unitinfo_dwarf2 DW_FORM_ref_addr is address size in DWARF version 2.
Bug #305513 contained a patch for some extra robustness checks. But
the real cause of crashing in the read_unitinfo_dwarf2 DWARF reader
seemed to have been this issue where DWARF version 2 DWZ partial_units
were read and DW_FORM_ref_addr had an unexpected size. This combination
is rare. DWARF version 4 is the current default version of GCC.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13367 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/m_debuginfo/readdwarf.c b/coregrind/m_debuginfo/readdwarf.c
index ce34bc7..52a9099 100644
--- a/coregrind/m_debuginfo/readdwarf.c
+++ b/coregrind/m_debuginfo/readdwarf.c
@@ -991,7 +991,7 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
UInt acode, abcode;
ULong atoffs, blklen;
Int level;
- /* UShort ver; */
+ UShort ver;
UChar addr_size;
UChar* p = unitblock_img;
@@ -1008,7 +1008,7 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
p += ui->dw64 ? 12 : 4;
/* version should be 2, 3 or 4 */
- /* ver = ML_(read_UShort)(p); */
+ ver = ML_(read_UShort)(p);
p += 2;
/* get offset in abbrev */
@@ -1122,7 +1122,7 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
case 0x0c: /* FORM_flag */ p++; break;
case 0x0d: /* FORM_sdata */ read_leb128S( &p ); break;
case 0x0f: /* FORM_udata */ read_leb128U( &p ); break;
- case 0x10: /* FORM_ref_addr */ p += ui->dw64 ? 8 : 4; break;
+ case 0x10: /* FORM_ref_addr */ p += (ver == 2) ? addr_size : (ui->dw64 ? 8 : 4); break;
case 0x11: /* FORM_ref1 */ p++; break;
case 0x12: /* FORM_ref2 */ p += 2; break;
case 0x13: /* FORM_ref4 */ p += 4; break;
commit 4c3b2379fb2cb97f762617df7770b042b1f8a59c
Author: mjw <mjw@a5019735-40e9-0310-863c-91ae7b9d1cf9>
Date: Wed Apr 17 13:48:29 2013 +0000
Simplify read_unitinfo_dwarf2. Only try to read the first DIE.
Bug #305513. We should only read the first DIE of a compilation unit.
Each compilation unit header is followed by a single DW_TAG_compile_unit
(or DW_TAG_partial_unit, but those aren't important here) and its children.
There is no reason to read any of the children at this point. If the first
DIE isn't a DW_TAG_compile_unit we are done, none of the child DIEs will
provide any useful information.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13369 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/m_debuginfo/readdwarf.c b/coregrind/m_debuginfo/readdwarf.c
index 52a9099..764295c 100644
--- a/coregrind/m_debuginfo/readdwarf.c
+++ b/coregrind/m_debuginfo/readdwarf.c
@@ -965,12 +965,14 @@ static UChar* lookup_abbrev( UChar* p, UInt acode )
}
/* Read general information for a particular compile unit block in
- * the .debug_info section.
+ * the .debug_info section. In particular read the name, compdir and
+ * stmt_list needed to parse the line number information.
*
* Input: - unitblock is the start of a compilation
* unit block in .debuginfo section
* - debugabbrev is start of .debug_abbrev section
* - debugstr is start of .debug_str section
+ * - debugstr_alt_img is start of .debug_str section in alt debug file
*
* Output: Fill members of ui pertaining to the compilation unit:
* - ui->name is the name of the compilation unit
@@ -990,7 +992,6 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
{
UInt acode, abcode;
ULong atoffs, blklen;
- Int level;
UShort ver;
UChar addr_size;
@@ -1021,39 +1022,32 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
end_img = unitblock_img
+ blklen + (ui->dw64 ? 12 : 4); /* End of this block */
- level = 0; /* Level in the abbrev tree */
abbrev_img = debugabbrev_img
+ atoffs; /* Abbreviation data for this block */
- /* Read the compilation unit entries */
- while ( p < end_img ) {
- Bool has_child;
+ /* Read the compilation unit entry - this is always the first DIE.
+ * See DWARF4 para 7.5. */
+ if ( p < end_img ) {
UInt tag;
acode = read_leb128U( &p ); /* abbreviation code */
- if ( acode == 0 ) {
- /* NULL entry used for padding - or last child for a sequence
- - see para 7.5.3 */
- level--;
- continue;
- }
/* Read abbreviation header */
abcode = read_leb128U( &abbrev_img ); /* abbreviation code */
if ( acode != abcode ) {
- /* We are in in children list, and must rewind to a
- * previously declared abbrev code. This code works but is
- * not triggered since we shortcut the parsing once we have
- * read the compile_unit block. This should only occur when
- * level > 0 */
+ /* This isn't illegal, but somewhat unlikely. Normally the
+ * first abbrev describes the first DIE, the compile_unit.
+ * But maybe this abbrevation data is shared with another
+ * or it is a NULL entry used for padding. See para 7.5.3. */
abbrev_img = lookup_abbrev( debugabbrev_img + atoffs, acode );
}
tag = read_leb128U( &abbrev_img );
- has_child = *(abbrev_img++) == 1; /* DW_CHILDREN_yes */
- if ( has_child )
- level++;
+ if ( tag != 0x0011 /*TAG_compile_unit*/ )
+ return; /* Not a compile unit (might be partial) or broken DWARF. */
+
+ abbrev_img++; /* DW_CHILDREN_yes or DW_CHILDREN_no */
/* And loop on entries */
for ( ; ; ) {
@@ -1151,16 +1145,9 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
else if ( name == 0x10 ) ui->stmt_list = cval; /* DW_AT_stmt_list */
}
}
- /* Shortcut the parsing once we have read the compile_unit block
- * That's enough info for us, and we are not gdb ! */
- if ( tag == 0x0011 /*TAG_compile_unit*/ )
- break;
- } /* Loop on each sub block */
-
- /* This test would be valid if we were not shortcutting the parsing
- if (level != 0)
- VG_(printf)( "#### Exiting debuginfo block at level %d !!!\n", level );
- */
+ } /* Just read the first DIE, if that wasn't the compile_unit then
+ * this might have been a partial unit or broken DWARF info.
+ * That's enough info for us, and we are not gdb ! */
}