[PING] Deal with intermixed 32-bit and 64-bit DWARF sections]

[PING] Deal with intermixed 32-bit and 64-bit DWARF sections]

[Mark Kettenis]

[ Elena, I never saw a reaction of you on this.  Could you please
  review it? ]

Date: Wed, 10 Nov 2004 22:28:46 +0100 (CET)
From: Mark Kettenis <kettenis@gnu.org>

Currently GDB crashes hard when we encounter both 32-bit anbd 64-bit
DWARF sections within the same compilation unit.  Keeping the mantra
"Be liberal what you accept, but complain loudly", this patch fixes
that.

Mark


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* dwarf2read.c (dwarf2_build_psymtabs_easy): Initailize initial
	length size of compilation header to zero.
	(dwarf2_build_psymtabs_hard): Adjust info_ptr before building
	psymtabs for included files.
	(create_all_comp_units): Initailize initial length size of
	compilation header to zero.
	(read_initial_length): Complain if both 32-bit and 64-bit DWARF
	sections are encountered within the same compilation header.
	(dwarf_decode_line_header): Pass compilation header in call to
	read_initial_length.

Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.169
diff -u -p -r1.169 dwarf2read.c
- --- dwarf2read.c 10 Nov 2004 20:40:33 -0000 1.169
+++ dwarf2read.c 10 Nov 2004 21:19:41 -0000
@@ -1243,6 +1243,7 @@ dwarf2_build_psymtabs_easy (struct objfi
       struct comp_unit_head cu_header;
       int bytes_read;
 
+      cu_header.initial_length_size = 0;
       entry_length = read_initial_length (abfd, pubnames_ptr, &cu_header,
                                          &bytes_read);
       pubnames_ptr += bytes_read;
@@ -1269,6 +1270,7 @@ read_comp_unit_head (struct comp_unit_he
 {
   int signed_addr;
   int bytes_read;
+
   cu_header->length = read_initial_length (abfd, info_ptr, cu_header,
                                            &bytes_read);
   info_ptr += bytes_read;
@@ -1533,6 +1535,9 @@ dwarf2_build_psymtabs_hard (struct objfi
          also happen.) This happens in VxWorks.  */
       free_named_symtabs (pst->filename);
 
+      info_ptr = beg_of_comp_unit + cu.header.length
+                                  + cu.header.initial_length_size;
+
       if (comp_unit_die.has_stmt_list)
         {
           /* Get the list of files included in the current compilation unit,
@@ -1540,9 +1545,6 @@ dwarf2_build_psymtabs_hard (struct objfi
           dwarf2_build_include_psymtabs (&cu, &comp_unit_die, pst);
         }
 
- -      info_ptr = beg_of_comp_unit + cu.header.length
- -                                  + cu.header.initial_length_size;
- -
       do_cleanups (back_to_inner);
     }
   do_cleanups (back_to);
@@ -1632,6 +1634,7 @@ create_all_comp_units (struct objfile *o
 
       /* Read just enough information to find out where the next
 	 compilation unit is.  */
+      cu_header.initial_length_size = 0;
       cu_header.length = read_initial_length (objfile->obfd, info_ptr,
 					      &cu_header, &bytes_read);
 
@@ -5850,7 +5853,7 @@ read_address (bfd *abfd, char *buf, stru
    As a side effect, this function sets the fields initial_length_size
    and offset_size in cu_header to the values appropriate for the
    length field.  (The format of the initial length field determines
- -   the width of file offsets to be fetched later with fetch_offset().)
+   the width of file offsets to be fetched later with read_offset().)
    
    [ Note:  read_initial_length() and read_offset() are based on the
      document entitled "DWARF Debugging Information Format", revision
@@ -5872,43 +5875,41 @@ static LONGEST
 read_initial_length (bfd *abfd, char *buf, struct comp_unit_head *cu_header,
                      int *bytes_read)
 {
- -  LONGEST retval = 0;
- -
- -  retval = bfd_get_32 (abfd, (bfd_byte *) buf);
+  LONGEST length = bfd_get_32 (abfd, (bfd_byte *) buf);
 
- -  if (retval == 0xffffffff)
+  if (length == 0xffffffff)
     {
- -      retval = bfd_get_64 (abfd, (bfd_byte *) buf + 4);
+      length = bfd_get_64 (abfd, (bfd_byte *) buf + 4);
       *bytes_read = 12;
- -      if (cu_header != NULL)
- -	{
- -	  cu_header->initial_length_size = 12;
- -	  cu_header->offset_size = 8;
- -	}
     }
- -  else if (retval == 0)
+  else if (length == 0)
     {
- -      /* Handle (non-standard) 64-bit DWARF2 formats such as that used
- -         by IRIX.  */
- -      retval = bfd_get_64 (abfd, (bfd_byte *) buf);
+      /* Handle the (non-standard) 64-bit DWARF2 format used by IRIX.  */
+      length = bfd_get_64 (abfd, (bfd_byte *) buf);
       *bytes_read = 8;
- -      if (cu_header != NULL)
- -	{
- -	  cu_header->initial_length_size = 8;
- -	  cu_header->offset_size = 8;
- -	}
     }
   else
     {
       *bytes_read = 4;
- -      if (cu_header != NULL)
- -	{
- -	  cu_header->initial_length_size = 4;
- -	  cu_header->offset_size = 4;
- -	}
     }
 
- -  return retval;
+  if (cu_header)
+    {
+      gdb_assert (cu_header->initial_length_size == 0
+		  || cu_header->initial_length_size == 4
+		  || cu_header->initial_length_size == 8
+		  || cu_header->initial_length_size == 12);
+
+      if (cu_header->initial_length_size != 0
+	  && cu_header->initial_length_size != *bytes_read)
+	complaint (&symfile_complaints,
+		   "intermixed 32-bit and 64-bit DWARF sections");
+
+      cu_header->initial_length_size = *bytes_read;
+      cu_header->offset_size = (*bytes_read == 4) ? 4 : 8;
+    }
+
+  return length;
 }
 
 /* Read an offset from the data stream.  The size of the offset is
@@ -6286,7 +6287,8 @@ dwarf_decode_line_header (unsigned int o
   line_ptr = dwarf2_per_objfile->line_buffer + offset;
 
   /* Read in the header.  */
- -  lh->total_length = read_initial_length (abfd, line_ptr, NULL, &bytes_read);
+  lh->total_length =
+    read_initial_length (abfd, line_ptr, &cu->header, &bytes_read);
   line_ptr += bytes_read;
   if (line_ptr + lh->total_length > (dwarf2_per_objfile->line_buffer
 				     + dwarf2_per_objfile->line_size))
------- End of forwarded message -------

[PING PING] Deal with intermixed 32-bit and 64-bit DWARF sections]

[Mark Kettenis]

[ Second ping ]

[ Elena, I never saw a reaction of you on this.  Could you please
  review it? ]

Date: Wed, 10 Nov 2004 22:28:46 +0100 (CET)
From: Mark Kettenis <kettenis@gnu.org>

Currently GDB crashes hard when we encounter both 32-bit anbd 64-bit
DWARF sections within the same compilation unit.  Keeping the mantra
"Be liberal what you accept, but complain loudly", this patch fixes
that.

Mark


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* dwarf2read.c (dwarf2_build_psymtabs_easy): Initailize initial
	length size of compilation header to zero.
	(dwarf2_build_psymtabs_hard): Adjust info_ptr before building
	psymtabs for included files.
	(create_all_comp_units): Initailize initial length size of
	compilation header to zero.
	(read_initial_length): Complain if both 32-bit and 64-bit DWARF
	sections are encountered within the same compilation header.
	(dwarf_decode_line_header): Pass compilation header in call to
	read_initial_length.

Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.169
diff -u -p -r1.169 dwarf2read.c
- --- dwarf2read.c 10 Nov 2004 20:40:33 -0000 1.169
+++ dwarf2read.c 10 Nov 2004 21:19:41 -0000
@@ -1243,6 +1243,7 @@ dwarf2_build_psymtabs_easy (struct objfi
       struct comp_unit_head cu_header;
       int bytes_read;
 
+      cu_header.initial_length_size = 0;
       entry_length = read_initial_length (abfd, pubnames_ptr, &cu_header,
                                          &bytes_read);
       pubnames_ptr += bytes_read;
@@ -1269,6 +1270,7 @@ read_comp_unit_head (struct comp_unit_he
 {
   int signed_addr;
   int bytes_read;
+
   cu_header->length = read_initial_length (abfd, info_ptr, cu_header,
                                            &bytes_read);
   info_ptr += bytes_read;
@@ -1533,6 +1535,9 @@ dwarf2_build_psymtabs_hard (struct objfi
          also happen.) This happens in VxWorks.  */
       free_named_symtabs (pst->filename);
 
+      info_ptr = beg_of_comp_unit + cu.header.length
+                                  + cu.header.initial_length_size;
+
       if (comp_unit_die.has_stmt_list)
         {
           /* Get the list of files included in the current compilation unit,
@@ -1540,9 +1545,6 @@ dwarf2_build_psymtabs_hard (struct objfi
           dwarf2_build_include_psymtabs (&cu, &comp_unit_die, pst);
         }
 
-      info_ptr = beg_of_comp_unit + cu.header.length
-                                  + cu.header.initial_length_size;
-
       do_cleanups (back_to_inner);
     }
   do_cleanups (back_to);
@@ -1632,6 +1634,7 @@ create_all_comp_units (struct objfile *o
 
       /* Read just enough information to find out where the next
 	 compilation unit is.  */
+      cu_header.initial_length_size = 0;
       cu_header.length = read_initial_length (objfile->obfd, info_ptr,
 					      &cu_header, &bytes_read);
 
@@ -5850,7 +5853,7 @@ read_address (bfd *abfd, char *buf, stru
    As a side effect, this function sets the fields initial_length_size
    and offset_size in cu_header to the values appropriate for the
    length field.  (The format of the initial length field determines
-   the width of file offsets to be fetched later with fetch_offset().)
+   the width of file offsets to be fetched later with read_offset().)
    
    [ Note:  read_initial_length() and read_offset() are based on the
      document entitled "DWARF Debugging Information Format", revision
@@ -5872,43 +5875,41 @@ static LONGEST
 read_initial_length (bfd *abfd, char *buf, struct comp_unit_head *cu_header,
                      int *bytes_read)
 {
-  LONGEST retval = 0;
-
-  retval = bfd_get_32 (abfd, (bfd_byte *) buf);
+  LONGEST length = bfd_get_32 (abfd, (bfd_byte *) buf);
 
-  if (retval == 0xffffffff)
+  if (length == 0xffffffff)
     {
-      retval = bfd_get_64 (abfd, (bfd_byte *) buf + 4);
+      length = bfd_get_64 (abfd, (bfd_byte *) buf + 4);
       *bytes_read = 12;
-      if (cu_header != NULL)
-	{
-	  cu_header->initial_length_size = 12;
-	  cu_header->offset_size = 8;
-	}
     }
-  else if (retval == 0)
+  else if (length == 0)
     {
-      /* Handle (non-standard) 64-bit DWARF2 formats such as that used
-         by IRIX.  */
-      retval = bfd_get_64 (abfd, (bfd_byte *) buf);
+      /* Handle the (non-standard) 64-bit DWARF2 format used by IRIX.  */
+      length = bfd_get_64 (abfd, (bfd_byte *) buf);
       *bytes_read = 8;
-      if (cu_header != NULL)
-	{
-	  cu_header->initial_length_size = 8;
-	  cu_header->offset_size = 8;
-	}
     }
   else
     {
       *bytes_read = 4;
-      if (cu_header != NULL)
-	{
-	  cu_header->initial_length_size = 4;
-	  cu_header->offset_size = 4;
-	}
     }
 
-  return retval;
+  if (cu_header)
+    {
+      gdb_assert (cu_header->initial_length_size == 0
+		  || cu_header->initial_length_size == 4
+		  || cu_header->initial_length_size == 8
+		  || cu_header->initial_length_size == 12);
+
+      if (cu_header->initial_length_size != 0
+	  && cu_header->initial_length_size != *bytes_read)
+	complaint (&symfile_complaints,
+		   "intermixed 32-bit and 64-bit DWARF sections");
+
+      cu_header->initial_length_size = *bytes_read;
+      cu_header->offset_size = (*bytes_read == 4) ? 4 : 8;
+    }
+
+  return length;
 }
 
 /* Read an offset from the data stream.  The size of the offset is
@@ -6286,7 +6287,8 @@ dwarf_decode_line_header (unsigned int o
   line_ptr = dwarf2_per_objfile->line_buffer + offset;
 
   /* Read in the header.  */
-  lh->total_length = read_initial_length (abfd, line_ptr, NULL, &bytes_read);
+  lh->total_length =
+    read_initial_length (abfd, line_ptr, &cu->header, &bytes_read);
   line_ptr += bytes_read;
   if (line_ptr + lh->total_length > (dwarf2_per_objfile->line_buffer
 				     + dwarf2_per_objfile->line_size))

Re: [PING PING] Deal with intermixed 32-bit and 64-bit DWARF sections]

[Daniel Jacobowitz]

On Tue, Jan 25, 2005 at 10:06:53PM +0100, Mark Kettenis wrote:
> [ Second ping ]
> 
> [ Elena, I never saw a reaction of you on this.  Could you please
>   review it? ]
> 
> Date: Wed, 10 Nov 2004 22:28:46 +0100 (CET)
> From: Mark Kettenis <kettenis@gnu.org>
> 
> Currently GDB crashes hard when we encounter both 32-bit anbd 64-bit
> DWARF sections within the same compilation unit.  Keeping the mantra
> "Be liberal what you accept, but complain loudly", this patch fixes
> that.

Mark,

Did you mean to check in the test case without the fix?  Not only does
it fail, it divides by zero, triggering the "infinite SIGFPE" bug
elsewhere reported in our bug database, and adding about ten minutes to
all of my testsuite runs.

-- 
Daniel Jacobowitz
CodeSourcery, LLC

Re: [PING PING] Deal with intermixed 32-bit and 64-bit DWARF sections]

[Elena Zannoni]

M.M. Kettenis writes:
 > Daniel Jacobowitz <drow@false.org> wrote: 
 > 
 > > On Tue, Jan 25, 2005 at 10:06:53PM +0100, Mark Kettenis wrote:
 > > > [ Second ping ]
 > > > 
 > > > [ Elena, I never saw a reaction of you on this.  Could you please
 > > >   review it? ]
 > > > 
 > > > Date: Wed, 10 Nov 2004 22:28:46 +0100 (CET)
 > > > From: Mark Kettenis <kettenis@gnu.org>
 > > > 
 > > > Currently GDB crashes hard when we encounter both 32-bit anbd 64-bit
 > > > DWARF sections within the same compilation unit.  Keeping the mantra
 > > > "Be liberal what you accept, but complain loudly", this patch fixes
 > > > that.
 > > 
 > > Mark,
 > > 
 > > Did you mean to check in the test case without the fix?  Not only does
 > > it fail, it divides by zero, triggering the "infinite SIGFPE" bug
 > > elsewhere reported in our bug database, and adding about ten minutes to
 > > all of my testsuite runs.
 > 
 > Sorry 'bout that.  But Elena didn't review it yet.  Fix is sitting at
 > home so I'll probably (ab)use my global maintainer rights to check this
 > in when I get back this weekend.
 > 

I asked Mark, in response to a private e-mail, to provide a testcase
as a necessary condition for his patch to go in.  No need for
threats.

I fixed the patch for internationalization and changes to an ifdeffed
out function and checked it in.

Re: [PING PING] Deal with intermixed 32-bit and 64-bit DWARF sections]

[Daniel Jacobowitz]

On Fri, Feb 25, 2005 at 11:23:49PM -0500, Elena Zannoni wrote:
> I asked Mark, in response to a private e-mail, to provide a testcase
> as a necessary condition for his patch to go in.  No need for
> threats.
> 
> I fixed the patch for internationalization and changes to an ifdeffed
> out function and checked it in.

Thanks!

-- 
Daniel Jacobowitz
CodeSourcery, LLC