[LLVMdev] The system library is gone for a long time.

Sat May 25 23:19:09 PDT 2013

OK, I'll resubmit it.

2013/5/26 David Majnemer <david.majnemer at gmail.com>:
> This patch has changed "System V IPC" to "Support V IPC". This seems to be an accident caused by some sort of automation.
>
> Sent from my iPhone
>
> On May 25, 2013, at 7:27 AM, 罗勇刚(Yonggang Luo)  <luoyonggang at gmail.com> wrote:
>
>> 0b5c0c9c868213fee1a8e3b571a96e2e099e8e1e
>> docs/SupportLibrary.rst | 247 ++++++++++++++++++++++++++++++++++++++++++++++++
>> docs/SystemLibrary.rst  | 247 ------------------------------------------------
>> docs/index.rst          |   6 +-
>> 3 files changed, 250 insertions(+), 250 deletions(-)
>>
>> diff --git a/docs/SupportLibrary.rst b/docs/SupportLibrary.rst
>> new file mode 100644
>> index 0000000..36ab49a
>> --- /dev/null
>> +++ b/docs/SupportLibrary.rst
>> @@ -0,0 +1,247 @@
>> +==============
>> +Support Library
>> +==============
>> +
>> +Abstract
>> +========
>> +
>> +This document provides some details on LLVM's Support Library, located in the
>> +source at ``lib/Support`` and ``include/llvm/Support``. The library's
>> purpose is
>> +to shield LLVM from the differences between operating systems for the few
>> +services LLVM needs from the operating system. Much of LLVM is written using
>> +portability features of standard C++. However, in a few areas, system dependent
>> +facilities are needed and the Support Library is the wrapper around
>> those system
>> +calls.
>> +
>> +By centralizing LLVM's use of operating system interfaces, we make it possible
>> +for the LLVM tool chain and runtime libraries to be more easily ported to new
>> +platforms since (theoretically) only ``lib/Support`` needs to be ported.  This
>> +library also unclutters the rest of LLVM from #ifdef use and special cases for
>> +specific operating systems. Such uses are replaced with simple calls to the
>> +interfaces provided in ``include/llvm/Support``.
>> +
>> +Note that the Support Library is not intended to be a complete operating system
>> +wrapper (such as the Adaptive Communications Environment (ACE) or Apache
>> +Portable Runtime (APR)), but only provides the functionality necessary to
>> +support LLVM.
>> +
>> +The Support Library was written by Reid Spencer who formulated the design based
>> +on similar work originating from the eXtensible Programming Support (XPS).
>> +Several people helped with the effort; especially, Jeff Cohen and Henrik Bach
>> +on the Win32 port.
>> +
>> +Keeping LLVM Portable
>> +=====================
>> +
>> +In order to keep LLVM portable, LLVM developers should adhere to a set of
>> +portability rules associated with the Support Library. Adherence to these rules
>> +should help the Support Library achieve its goal of shielding LLVM from the
>> +variations in operating system interfaces and doing so efficiently.  The
>> +following sections define the rules needed to fulfill this objective.
>> +
>> +Don't Include Support Headers
>> +----------------------------
>> +
>> +Except in ``lib/Support``, no LLVM source code should directly ``#include`` a
>> +system header. Care has been taken to remove all such ``#includes`` from LLVM
>> +while ``lib/Support`` was being developed.  Specifically this means that header
>> +files like "``unistd.h``", "``windows.h``", "``stdio.h``", and "``string.h``"
>> +are forbidden to be included by LLVM source code outside the implementation of
>> +``lib/Support``.
>> +
>> +To obtain system-dependent functionality, existing interfaces to the system
>> +found in ``include/llvm/Support`` should be used. If an appropriate
>> interface is
>> +not available, it should be added to ``include/llvm/Support`` and
>> implemented in
>> +``lib/Support`` for all supported platforms.
>> +
>> +Don't Expose Support Headers
>> +---------------------------
>> +
>> +The Support Library must shield LLVM from **all** system headers. To obtain
>> +system level functionality, LLVM source must ``#include
>> "llvm/Support/Thing.h"``
>> +and nothing else. This means that ``Thing.h`` cannot expose any system header
>> +files. This protects LLVM from accidentally using system specific functionality
>> +and only allows it via the ``lib/Support`` interface.
>> +
>> +Use Standard C Headers
>> +----------------------
>> +
>> +The **standard** C headers (the ones beginning with "c") are allowed to be
>> +exposed through the ``lib/Support`` interface. These headers and the
>> things they
>> +declare are considered to be platform agnostic. LLVM source files may include
>> +them directly or obtain their inclusion through ``lib/Support`` interfaces.
>> +
>> +Use Standard C++ Headers
>> +------------------------
>> +
>> +The **standard** C++ headers from the standard C++ library and standard
>> +template library may be exposed through the ``lib/Support`` interface. These
>> +headers and the things they declare are considered to be platform agnostic.
>> +LLVM source files may include them or obtain their inclusion through
>> +``lib/Support`` interfaces.
>> +
>> +High Level Interface
>> +--------------------
>> +
>> +The entry points specified in the interface of ``lib/Support`` must be aimed at
>> +completing some reasonably high level task needed by LLVM. We do not want to
>> +simply wrap each operating system call. It would be preferable to wrap several
>> +operating system calls that are always used in conjunction with one another by
>> +LLVM.
>> +
>> +For example, consider what is needed to execute a program, wait for it to
>> +complete, and return its result code. On Unix, this involves the following
>> +operating system calls: ``getenv``, ``fork``, ``execve``, and ``wait``. The
>> +correct thing for ``lib/Support`` to provide is a function, say
>> +``ExecuteProgramAndWait``, that implements the functionality completely.  what
>> +we don't want is wrappers for the operating system calls involved.
>> +
>> +There must **not** be a one-to-one relationship between operating system
>> +calls and the Support library's interface. Any such interface function will be
>> +suspicious.
>> +
>> +No Unused Functionality
>> +-----------------------
>> +
>> +There must be no functionality specified in the interface of ``lib/Support``
>> +that isn't actually used by LLVM. We're not writing a general purpose operating
>> +system wrapper here, just enough to satisfy LLVM's needs. And, LLVM doesn't
>> +need much. This design goal aims to keep the ``lib/Support``
>> interface small and
>> +understandable which should foster its actual use and adoption.
>> +
>> +No Duplicate Implementations
>> +----------------------------
>> +
>> +The implementation of a function for a given platform must be written exactly
>> +once. This implies that it must be possible to apply a function's
>> +implementation to multiple operating systems if those operating systems can
>> +share the same implementation. This rule applies to the set of operating
>> +systems supported for a given class of operating system (e.g. Unix, Win32).
>> +
>> +No Virtual Methods
>> +------------------
>> +
>> +The Support Library interfaces can be called quite frequently by LLVM. In order
>> +to make those calls as efficient as possible, we discourage the use of virtual
>> +methods. There is no need to use inheritance for implementation differences, it
>> +just adds complexity. The ``#include`` mechanism works just fine.
>> +
>> +No Exposed Functions
>> +--------------------
>> +
>> +Any functions defined by system libraries (i.e. not defined by ``lib/Support``)
>> +must not be exposed through the ``lib/Support`` interface, even if the header
>> +file for that function is not exposed. This prevents inadvertent use of system
>> +specific functionality.
>> +
>> +For example, the ``stat`` system call is notorious for having variations in the
>> +data it provides. ``lib/Support`` must not declare ``stat`` nor allow it to be
>> +declared. Instead it should provide its own interface to discovering
>> +information about files and directories. Those interfaces may be implemented in
>> +terms of ``stat`` but that is strictly an implementation detail. The interface
>> +provided by the Support Library must be implemented on all platforms
>> (even those
>> +without ``stat``).
>> +
>> +No Exposed Data
>> +---------------
>> +
>> +Any data defined by system libraries (i.e. not defined by ``lib/Support``) must
>> +not be exposed through the ``lib/Support`` interface, even if the header file
>> +for that function is not exposed. As with functions, this prevents inadvertent
>> +use of data that might not exist on all platforms.
>> +
>> +Minimize Soft Errors
>> +--------------------
>> +
>> +Operating system interfaces will generally provide error results for every
>> +little thing that could go wrong. In almost all cases, you can divide these
>> +error results into two groups: normal/good/soft and abnormal/bad/hard. That is,
>> +some of the errors are simply information like "file not found", "insufficient
>> +privileges", etc. while other errors are much harder like "out of space", "bad
>> +disk sector", or "system call interrupted". We'll call the first group "*soft*"
>> +errors and the second group "*hard*" errors.
>> +
>> +``lib/Support`` must always attempt to minimize soft errors.  This is a design
>> +requirement because the minimization of soft errors can affect the granularity
>> +and the nature of the interface. In general, if you find that you're wanting to
>> +throw soft errors, you must review the granularity of the interface because it
>> +is likely you're trying to implement something that is too low level. The rule
>> +of thumb is to provide interface functions that **can't** fail, except when
>> +faced with hard errors.
>> +
>> +For a trivial example, suppose we wanted to add an "``OpenFileForWriting``"
>> +function. For many operating systems, if the file doesn't exist, attempting to
>> +open the file will produce an error.  However, ``lib/Support`` should
>> not simply
>> +throw that error if it occurs because its a soft error. The problem is that the
>> +interface function, ``OpenFileForWriting`` is too low level. It should be
>> +``OpenOrCreateFileForWriting``. In the case of the soft "doesn't exist" error,
>> +this function would just create it and then open it for writing.
>> +
>> +This design principle needs to be maintained in ``lib/Support`` because it
>> +avoids the propagation of soft error handling throughout the rest of LLVM.
>> +Hard errors will generally just cause a termination for an LLVM tool so don't
>> +be bashful about throwing them.
>> +
>> +Rules of thumb:
>> +
>> +#. Don't throw soft errors, only hard errors.
>> +
>> +#. If you're tempted to throw a soft error, re-think the interface.
>> +
>> +#. Handle internally the most common normal/good/soft error conditions
>> +   so the rest of LLVM doesn't have to.
>> +
>> +No throw Specifications
>> +-----------------------
>> +
>> +None of the ``lib/Support`` interface functions may be declared with C++
>> +``throw()`` specifications on them. This requirement makes sure that the
>> +compiler does not insert additional exception handling code into the interface
>> +functions. This is a performance consideration: ``lib/Support``
>> functions are at
>> +the bottom of many call chains and as such can be frequently called. We need
>> +them to be as efficient as possible.  However, no routines in the system
>> +library should actually throw exceptions.
>> +
>> +Code Organization
>> +-----------------
>> +
>> +Implementations of the Support Library interface are separated by their general
>> +class of operating system. Currently only Unix and Win32 classes are defined
>> +but more could be added for other operating system classifications.  To
>> +distinguish which implementation to compile, the code in ``lib/Support`` uses
>> +the ``LLVM_ON_UNIX`` and ``LLVM_ON_WIN32`` ``#defines`` provided via configure
>> +through the ``llvm/Config/config.h`` file. Each source file in ``lib/Support``,
>> +after implementing the generic (operating system independent) functionality
>> +needs to include the correct implementation using a set of
>> +``#if defined(LLVM_ON_XYZ)`` directives. For example, if we had
>> +``lib/Support/Path.cpp``, we'd expect to see in that file:
>> +
>> +.. code-block:: c++
>> +
>> +  #if defined(LLVM_ON_UNIX)
>> +  #include "Unix/Path.inc"
>> +  #endif
>> +  #if defined(LLVM_ON_WIN32)
>> +  #include "Windows/Path.inc"
>> +  #endif
>> +
>> +The implementation in ``lib/Support/Unix/Path.inc`` should handle all Unix
>> +variants. The implementation in ``lib/Support/Windows/Path.inc``
>> should handle all
>> +Win32 variants.  What this does is quickly differentiate the basic class of
>> +operating system that will provide the implementation. The specific details for
>> +a given platform must still be determined through the use of ``#ifdef``.
>> +
>> +Consistent Semantics
>> +--------------------
>> +
>> +The implementation of a ``lib/Support`` interface can vary drastically between
>> +platforms. That's okay as long as the end result of the interface function is
>> +the same. For example, a function to create a directory is pretty straight
>> +forward on all operating system. Support V IPC on the other hand isn't even
>> +supported on all platforms. Instead of "supporting" Support V IPC,
>> +``lib/Support`` should provide an interface to the basic concept of
>> +inter-process communications. The implementations might use Support V IPC if
>> +that was available or named pipes, or whatever gets the job done effectively
>> +for a given operating system.  In all cases, the interface and the
>> +implementation must be semantically consistent.
>> +
>> diff --git a/docs/SystemLibrary.rst b/docs/SystemLibrary.rst
>> deleted file mode 100644
>> index 0d0f4fa..0000000
>> --- a/docs/SystemLibrary.rst
>> +++ /dev/null
>> @@ -1,247 +0,0 @@
>> -==============
>> -System Library
>> -==============
>> -
>> -Abstract
>> -========
>> -
>> -This document provides some details on LLVM's System Library, located in the
>> -source at ``lib/System`` and ``include/llvm/System``. The library's purpose is
>> -to shield LLVM from the differences between operating systems for the few
>> -services LLVM needs from the operating system. Much of LLVM is written using
>> -portability features of standard C++. However, in a few areas, system dependent
>> -facilities are needed and the System Library is the wrapper around those system
>> -calls.
>> -
>> -By centralizing LLVM's use of operating system interfaces, we make it possible
>> -for the LLVM tool chain and runtime libraries to be more easily ported to new
>> -platforms since (theoretically) only ``lib/System`` needs to be ported.  This
>> -library also unclutters the rest of LLVM from #ifdef use and special cases for
>> -specific operating systems. Such uses are replaced with simple calls to the
>> -interfaces provided in ``include/llvm/System``.
>> -
>> -Note that the System Library is not intended to be a complete operating system
>> -wrapper (such as the Adaptive Communications Environment (ACE) or Apache
>> -Portable Runtime (APR)), but only provides the functionality necessary to
>> -support LLVM.
>> -
>> -The System Library was written by Reid Spencer who formulated the design based
>> -on similar work originating from the eXtensible Programming System (XPS).
>> -Several people helped with the effort; especially, Jeff Cohen and Henrik Bach
>> -on the Win32 port.
>> -
>> -Keeping LLVM Portable
>> -=====================
>> -
>> -In order to keep LLVM portable, LLVM developers should adhere to a set of
>> -portability rules associated with the System Library. Adherence to these rules
>> -should help the System Library achieve its goal of shielding LLVM from the
>> -variations in operating system interfaces and doing so efficiently.  The
>> -following sections define the rules needed to fulfill this objective.
>> -
>> -Don't Include System Headers
>> -----------------------------
>> -
>> -Except in ``lib/System``, no LLVM source code should directly ``#include`` a
>> -system header. Care has been taken to remove all such ``#includes`` from LLVM
>> -while ``lib/System`` was being developed.  Specifically this means that header
>> -files like "``unistd.h``", "``windows.h``", "``stdio.h``", and "``string.h``"
>> -are forbidden to be included by LLVM source code outside the implementation of
>> -``lib/System``.
>> -
>> -To obtain system-dependent functionality, existing interfaces to the system
>> -found in ``include/llvm/System`` should be used. If an appropriate interface is
>> -not available, it should be added to ``include/llvm/System`` and implemented in
>> -``lib/System`` for all supported platforms.
>> -
>> -Don't Expose System Headers
>> ----------------------------
>> -
>> -The System Library must shield LLVM from **all** system headers. To obtain
>> -system level functionality, LLVM source must ``#include "llvm/System/Thing.h"``
>> -and nothing else. This means that ``Thing.h`` cannot expose any system header
>> -files. This protects LLVM from accidentally using system specific functionality
>> -and only allows it via the ``lib/System`` interface.
>> -
>> -Use Standard C Headers
>> -----------------------
>> -
>> -The **standard** C headers (the ones beginning with "c") are allowed to be
>> -exposed through the ``lib/System`` interface. These headers and the things they
>> -declare are considered to be platform agnostic. LLVM source files may include
>> -them directly or obtain their inclusion through ``lib/System`` interfaces.
>> -
>> -Use Standard C++ Headers
>> -------------------------
>> -
>> -The **standard** C++ headers from the standard C++ library and standard
>> -template library may be exposed through the ``lib/System`` interface. These
>> -headers and the things they declare are considered to be platform agnostic.
>> -LLVM source files may include them or obtain their inclusion through
>> -``lib/System`` interfaces.
>> -
>> -High Level Interface
>> ---------------------
>> -
>> -The entry points specified in the interface of ``lib/System`` must be aimed at
>> -completing some reasonably high level task needed by LLVM. We do not want to
>> -simply wrap each operating system call. It would be preferable to wrap several
>> -operating system calls that are always used in conjunction with one another by
>> -LLVM.
>> -
>> -For example, consider what is needed to execute a program, wait for it to
>> -complete, and return its result code. On Unix, this involves the following
>> -operating system calls: ``getenv``, ``fork``, ``execve``, and ``wait``. The
>> -correct thing for ``lib/System`` to provide is a function, say
>> -``ExecuteProgramAndWait``, that implements the functionality completely.  what
>> -we don't want is wrappers for the operating system calls involved.
>> -
>> -There must **not** be a one-to-one relationship between operating system
>> -calls and the System library's interface. Any such interface function will be
>> -suspicious.
>> -
>> -No Unused Functionality
>> ------------------------
>> -
>> -There must be no functionality specified in the interface of ``lib/System``
>> -that isn't actually used by LLVM. We're not writing a general purpose operating
>> -system wrapper here, just enough to satisfy LLVM's needs. And, LLVM doesn't
>> -need much. This design goal aims to keep the ``lib/System`` interface small and
>> -understandable which should foster its actual use and adoption.
>> -
>> -No Duplicate Implementations
>> -----------------------------
>> -
>> -The implementation of a function for a given platform must be written exactly
>> -once. This implies that it must be possible to apply a function's
>> -implementation to multiple operating systems if those operating systems can
>> -share the same implementation. This rule applies to the set of operating
>> -systems supported for a given class of operating system (e.g. Unix, Win32).
>> -
>> -No Virtual Methods
>> -------------------
>> -
>> -The System Library interfaces can be called quite frequently by LLVM. In order
>> -to make those calls as efficient as possible, we discourage the use of virtual
>> -methods. There is no need to use inheritance for implementation differences, it
>> -just adds complexity. The ``#include`` mechanism works just fine.
>> -
>> -No Exposed Functions
>> ---------------------
>> -
>> -Any functions defined by system libraries (i.e. not defined by ``lib/System``)
>> -must not be exposed through the ``lib/System`` interface, even if the header
>> -file for that function is not exposed. This prevents inadvertent use of system
>> -specific functionality.
>> -
>> -For example, the ``stat`` system call is notorious for having variations in the
>> -data it provides. ``lib/System`` must not declare ``stat`` nor allow it to be
>> -declared. Instead it should provide its own interface to discovering
>> -information about files and directories. Those interfaces may be implemented in
>> -terms of ``stat`` but that is strictly an implementation detail. The interface
>> -provided by the System Library must be implemented on all platforms (even those
>> -without ``stat``).
>> -
>> -No Exposed Data
>> ----------------
>> -
>> -Any data defined by system libraries (i.e. not defined by ``lib/System``) must
>> -not be exposed through the ``lib/System`` interface, even if the header file
>> -for that function is not exposed. As with functions, this prevents inadvertent
>> -use of data that might not exist on all platforms.
>> -
>> -Minimize Soft Errors
>> ---------------------
>> -
>> -Operating system interfaces will generally provide error results for every
>> -little thing that could go wrong. In almost all cases, you can divide these
>> -error results into two groups: normal/good/soft and abnormal/bad/hard. That is,
>> -some of the errors are simply information like "file not found", "insufficient
>> -privileges", etc. while other errors are much harder like "out of space", "bad
>> -disk sector", or "system call interrupted". We'll call the first group "*soft*"
>> -errors and the second group "*hard*" errors.
>> -
>> -``lib/System`` must always attempt to minimize soft errors.  This is a design
>> -requirement because the minimization of soft errors can affect the granularity
>> -and the nature of the interface. In general, if you find that you're wanting to
>> -throw soft errors, you must review the granularity of the interface because it
>> -is likely you're trying to implement something that is too low level. The rule
>> -of thumb is to provide interface functions that **can't** fail, except when
>> -faced with hard errors.
>> -
>> -For a trivial example, suppose we wanted to add an "``OpenFileForWriting``"
>> -function. For many operating systems, if the file doesn't exist, attempting to
>> -open the file will produce an error.  However, ``lib/System`` should not simply
>> -throw that error if it occurs because its a soft error. The problem is that the
>> -interface function, ``OpenFileForWriting`` is too low level. It should be
>> -``OpenOrCreateFileForWriting``. In the case of the soft "doesn't exist" error,
>> -this function would just create it and then open it for writing.
>> -
>> -This design principle needs to be maintained in ``lib/System`` because it
>> -avoids the propagation of soft error handling throughout the rest of LLVM.
>> -Hard errors will generally just cause a termination for an LLVM tool so don't
>> -be bashful about throwing them.
>> -
>> -Rules of thumb:
>> -
>> -#. Don't throw soft errors, only hard errors.
>> -
>> -#. If you're tempted to throw a soft error, re-think the interface.
>> -
>> -#. Handle internally the most common normal/good/soft error conditions
>> -   so the rest of LLVM doesn't have to.
>> -
>> -No throw Specifications
>> ------------------------
>> -
>> -None of the ``lib/System`` interface functions may be declared with C++
>> -``throw()`` specifications on them. This requirement makes sure that the
>> -compiler does not insert additional exception handling code into the interface
>> -functions. This is a performance consideration: ``lib/System`` functions are at
>> -the bottom of many call chains and as such can be frequently called. We need
>> -them to be as efficient as possible.  However, no routines in the system
>> -library should actually throw exceptions.
>> -
>> -Code Organization
>> ------------------
>> -
>> -Implementations of the System Library interface are separated by their general
>> -class of operating system. Currently only Unix and Win32 classes are defined
>> -but more could be added for other operating system classifications.  To
>> -distinguish which implementation to compile, the code in ``lib/System`` uses
>> -the ``LLVM_ON_UNIX`` and ``LLVM_ON_WIN32`` ``#defines`` provided via configure
>> -through the ``llvm/Config/config.h`` file. Each source file in ``lib/System``,
>> -after implementing the generic (operating system independent) functionality
>> -needs to include the correct implementation using a set of
>> -``#if defined(LLVM_ON_XYZ)`` directives. For example, if we had
>> -``lib/System/File.cpp``, we'd expect to see in that file:
>> -
>> -.. code-block:: c++
>> -
>> -  #if defined(LLVM_ON_UNIX)
>> -  #include "Unix/File.cpp"
>> -  #endif
>> -  #if defined(LLVM_ON_WIN32)
>> -  #include "Win32/File.cpp"
>> -  #endif
>> -
>> -The implementation in ``lib/System/Unix/File.cpp`` should handle all Unix
>> -variants. The implementation in ``lib/System/Win32/File.cpp`` should handle all
>> -Win32 variants.  What this does is quickly differentiate the basic class of
>> -operating system that will provide the implementation. The specific details for
>> -a given platform must still be determined through the use of ``#ifdef``.
>> -
>> -Consistent Semantics
>> ---------------------
>> -
>> -The implementation of a ``lib/System`` interface can vary drastically between
>> -platforms. That's okay as long as the end result of the interface function is
>> -the same. For example, a function to create a directory is pretty straight
>> -forward on all operating system. System V IPC on the other hand isn't even
>> -supported on all platforms. Instead of "supporting" System V IPC,
>> -``lib/System`` should provide an interface to the basic concept of
>> -inter-process communications. The implementations might use System V IPC if
>> -that was available or named pipes, or whatever gets the job done effectively
>> -for a given operating system.  In all cases, the interface and the
>> -implementation must be semantically consistent.
>> -
>> diff --git a/docs/index.rst b/docs/index.rst
>> index 6b182da..65dc126 100644
>> --- a/docs/index.rst
>> +++ b/docs/index.rst
>> @@ -220,7 +220,7 @@ For API clients and LLVM developers.
>>    DebuggingJITedCode
>>    GoldPlugin
>>    MarkedUpDisassembly
>> -   SystemLibrary
>> +   SupportLibrary
>>    SourceLevelDebugging
>>    Vectorizers
>>    WritingAnLLVMBackend
>> @@ -271,8 +271,8 @@ For API clients and LLVM developers.
>> :doc:`BitCodeFormat`
>>    This describes the file format and encoding used for LLVM "bc" files.
>>
>> -:doc:`System Library <SystemLibrary>`
>> -   This document describes the LLVM System Library (``lib/System``) and
>> +:doc:`Support Library <SupportLibrary>`
>> +   This document describes the LLVM Support Library (``lib/Support``) and
>>    how to keep LLVM source code portable
>>
>> :doc:`LinkTimeOptimization`
>>
>> --
>>         此致
>> 礼
>> 罗勇刚
>> Yours
>>    sincerely,
>> Yonggang Luo
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits

-- 
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo