MySQL Bugs: #36703: Unknown symbol EncodedDataStream::decode when linking mysqld with Sun Studio

Bug #36703	Unknown symbol EncodedDataStream::decode when linking mysqld with Sun Studio
Submitted:	13 May 2008 23:52	Modified:	9 Oct 2008 12:54
Reporter:	Olav Sandstaa	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Falcon storage engine	Severity:	S3 (Non-critical)
Version:	6.0.6	OS:	Solaris
Assigned to:	Olav Sandstå	CPU Architecture:	Any
Tags:	Sun Studio

Description:
When compiling MySQL based on the mysql-6.0-falcon-team tree I get the following linking error when linking mysqld:

Undefined                       first referenced
 symbol                             in file
const unsigned char*EncodedDataStream::decode(const unsigned char*,Value*,bool) ../storage/falcon/libfalcon.a(libhafalcon_a-TableSpaceManager.o)
ld: fatal: Symbol referencing errors. No output written to mysqld

How to repeat:
Check out the source from mysql-6.0-falcon-team tree and compile it using Sun Studio compiler on Solaris.

Suggested fix:
Fix the source code that produces this problem.

Using nm to get the symbol information from the libhafalcon_a-EncodedDataStream.o I get the following for the "undefined" function:

[69]    |      8472|    3024|FUNC |GLOB |0    |2      |const unsigned char*EncodedDataStream::decode(const unsigned char*,Value*,bool)
                                                       [__1cREncodedDataStreamGdecode6FpkCpnFValue_b_p1_]

Doing the same on the libhafalcon_a-TableSpaceManager.o file I see:

[56]    |         0|       0|FUNC |GLOB |0    |UNDEF  |const unsigned char*EncodedDataStream::decode(const unsigned char*,Value*,bool)
                                                       [__1cREncodedDataStreamGdecode6FpkCpnFValue_b_2_]

Based on this it seems like the function is included in the correct object file and the demangled versions seems identical but the "non-mangled"(?) name seems to differ on the last 2-3 characters.

Thank you for a problem report. What exact versions of Solaris and Sun Studio were used?

Solaris version used: Solaris 10 update 5:

                         Solaris 10 5/08 s10s_u5wos_10 SPARC
           Copyright 2008 Sun Microsystems, Inc.  All Rights Reserved.
                        Use is subject to license terms.
                             Assembled 24 March 2008

Compiler version used: Sun Studio 12:

os136802@techra29:> /opt/studio12/SUNWspro/bin/CC -V
CC: Sun C++ 5.9 SunOS_sparc Patch 124863-02 2007/12/18

In EncodedDataStream.h the decode() method have the following signature:

    static const unsigned char* decode (const unsigned char *ptr, Value *value, bool copyFlag);

In the implementation in EncodedDataStream.cpp the decode() method have the following signature:

   const UCHAR* EncodedDataStream::decode(const UCHAR *ptr, Value *value, bool copyFlag)

Given that UCHAR has the following definition (in storage/falcon/Engine.h):

   typedef unsigned char  UCHAR;

the compiler is not complaining about this "difference". Still the Sun Studio 12 compiler gives this method a different symbol name in the object file compared the what it expects in the file that is calling the method.

Replacing the UCHAR with "unsigned char" in the signature for the decode() method in storage/falcon/DecodedDataStream.cpp above solves the linking problem. 

Unless anyone objects I will make a patch with this change. I am considering whether this should be reported as a Sun Studio compiler bug or not?

Olav,

what about rewriting the signature to:

   static const UCHAR* decode (const unsigned char *ptr, Value *value, bool copyFlag);

With the help from Wlad and Google this seems to be a known problem with the Sun Studio 12 C++ compiler. See:

  http://docs.sun.com/source/820-4155/c++.html#cNameMangling

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/47247

2683 Olav Sandstaa	2008-05-30
      A fix for Bug#36703: Unknown symbol EncodedDataStream::decode when linking mysqld with Sun Studio
      
      The problem was due to Sun Studio compiler produced a different symbol names in the object files for the decode()
      method for the implementation of the method and when it was called.
      This was triggered due to that the declartion of the method used "unsigned char" while the definition of the method used a UCHAR (which is typedef unsigned char). 
      
      Fixed this problem by using UCHAR in both declaration and definition.

Hakan,

Thanks for the suggestion to rewrite the declaration to use UCHAR instead of changing the definition to use "unsigned char". I have submitted a patch which does this. The "drawback" of this was that I also needed to include a new .h file (Engine.h) in the EncodedDataStream.h file.

Fix is in version 6.0.7

Documented in the 6.0.7 changelog as follows:

        mysqld failed to build using the Sun Studio compiler.