Windows Native mangles bytecode output using cout

[llvmbot]

Bugzilla Link	787
Resolution	FIXED
Resolved on	Feb 22, 2010 12:45
Version	1.0
OS	Windows XP
Reporter	LLVM Bugzilla Contributor
CC	@lattner

Extended Description

When using the Windows native build of version 1.6 (I've seen no sign this was
fixed in 1.7, although testing that is tricky since the win32 build in 1.7 is
pretty unstable) llvm-as output using cout uses text output, replacing newlines
with CR+LF characters, mangling the output.

Examples of this can be found in test case
Regression/Linker/2002-07-17-GlobalFail.ll where the following line has an error:
llvm-as < 2002-07-17-GlobalFail.ll > %s.bc
because the output is being written to stdout and redirected to %s.bc.
This also occurs when getting input from stdin (cin) in llc, lli, llvm-dis, and opt.

A solution to this has been discussed on the mailing list under the name "Binary
output to cout on Windows", and is reposted below, essentially changing the mode
on stdin and stdout to binary.

The code that needs to be run before input/output is done on stdin/stdout is:
int result = _setmode( _fileno(stdin), _O_BINARY );
if( result == -1 )
{ std::cerr<<"Cannot set input mode to binary."<<std::endl; return 1; }
result = _setmode( _fileno(stdout), _O_BINARY );
if( result == -1 )
{ std::cerr<<"Cannot set output mode to binary."<<std::endl; return 1; }
Error checking included. The files that need to be included for this code are
, <io.h>, and <fcntl.h>.

[llvmbot]

Thanks Michael,

I won't be able to get to this for a few days (probably this weekend). If you'd
like to submit some patches, here's basically what you need to do:

1. Add a function to include/llvm/System/Program.h to set binary mode on a stream
2. Implement that function in lib/System/Win32/Program.inc and
   lib/System/Unix/Program.inc
3. Call that function in lib/Bytecode/Reader/Reader.cpp and
   lib/Bytecode/Writer/Writer.cpp
4. Alternatively, call the function in the various tools//.cpp as appropriate.
   This should go in the main program.

I'm not sure if step 3 will work because of the lateness of the time at which
the reader or writer is invoked. Step 3 is the right place to put this in
because it will automatically affect all programs that read or write bytecode
files. However, it might not be technically feasible depending on the
requirements of the operating system (setting it before any I/O is done).

Thanks for filing this well written PR!

[llvmbot]

Adding the call in Bytecode/Writer/Writer.cpp WriteBytecodeToFile() and
Bytecode/Reader/ReaderWrappers.cpp BytecodeBufferReader::BytecodeBufferReader()
seems to work correctly.

[llvmbot]

Michael,

Since you have it working, could you provide the patch so we can commit the
change and resolve this bug?

Thanks,

Reid.

[llvmbot]

I meant to say BytecodeStdinReader::BytecodeStdinReader() rather than
Bytecode/Reader/ReaderWrappers.cpp BytecodeBufferReader::BytecodeBufferReader()

I downloaded the compressed source rather than getting it with CVS. I'm
retesting the change with a clean version of the source, then I'll submit a patch.

[llvmbot]

Sounds great. I look forward to closing this bug and solving this problem for
all win32 users.

Reid.

[llvmbot]

Patch to fix this bug.

[llvmbot]

Thanks for the patch. The output for the BytecodeWriter isn't quite correct. The
call will change std::cout but the bytecode writer might not be writing to
std::cout, so it needs to check. In any event, I'll use the patch and fix this
myself.

Thanks!

[llvmbot]

That shouldn't be an issue, since whenever you're not writing to std::cout,
you're writing to a stream you've created, and therefore have constructed with
the binary mode flag.

[llvmbot]

Nevermind, I misinterpreted what you were saying.

[llvmbot]

Michael,

Your patch has been applied, tested, and found to work on Unix. This bug is now
resolved. Could you please verify that the patch fixes the issue on your Windows
platform. If so, please mark this PR as "VERIFIED".

Thanks,

Reid.

Patches Applied:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20060605/035455.html
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20060605/035456.html
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20060605/035457.html
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20060605/035458.html
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20060605/035459.html

[llvmbot]

I have the patch working as you've entered it using the base 1.7 release.
However there seem to be errors in the Visual Studio build process in the latest
cvs version that prevent it from building.

[llvmbot]

Yeah, Jeff Cohen usually updates the win32 stuff but I haven't seen him around
lately. I'd do it but I don't have a win32 build environment. If you can update
the build stuff yourself for Visual Studio, we'll accept the patch. Or perhaps
you could get in contact with Jeff to update it.