llvm-6502/lib/System
2006-05-07 02:51:51 +00:00
..
Unix For PR351: 2005-12-22 20:00:16 +00:00
Win32 Unlike Unix, Windows won't let a file be implicitly replaced via renaming without explicit permission. 2006-05-07 02:51:51 +00:00
Alarm.cpp Implement a generic polled Alarm function. This merely removes the system 2005-12-22 03:23:46 +00:00
DynamicLibrary.cpp Add AddSymbol() method to DynamicLibrary to work around Windows limitation 2006-01-30 04:33:51 +00:00
LICENSE.TXT License for this library. 2004-08-25 00:48:02 +00:00
ltdl.c Fix the llvm bootstrap 2005-02-13 23:37:09 +00:00
ltdl.h Eliminate tabs and trailing spaces. 2005-07-27 05:53:44 +00:00
Makefile Add the README files to the distribution. 2006-04-13 06:39:24 +00:00
MappedFile.cpp Remove vim settings from source code; people should use llvm/utils/vim/vimrc 2005-05-05 22:33:09 +00:00
Memory.cpp Remove vim settings from source code; people should use llvm/utils/vim/vimrc 2005-05-05 22:33:09 +00:00
Mutex.cpp Add checks for __OpenBSD__. 2006-04-17 17:55:41 +00:00
Path.cpp For PR495: 2005-07-07 23:21:43 +00:00
Process.cpp Remove vim settings from source code; people should use llvm/utils/vim/vimrc 2005-05-05 22:33:09 +00:00
Program.cpp Remove vim settings from source code; people should use llvm/utils/vim/vimrc 2005-05-05 22:33:09 +00:00
README.txt Convert llvm.cs.uiuc.edu -> llvm.org 2006-03-14 05:54:52 +00:00
Signals.cpp Remove vim settings from source code; people should use llvm/utils/vim/vimrc 2005-05-05 22:33:09 +00:00
TimeValue.cpp Remove vim settings from source code; people should use llvm/utils/vim/vimrc 2005-05-05 22:33:09 +00:00

Design Of lib/System
====================

The software in this directory is designed to completely shield LLVM from any
and all operating system specific functionality. It is not intended to be a
complete operating system wrapper (such as ACE), but only to provide the
functionality necessary to support LLVM.

The software located here, of necessity, has very specific and stringent design
rules. Violation of these rules means that cracks in the shield could form and
the primary goal of the library is defeated. By consistently using this library,
LLVM becomes more easily ported to new platforms since the only thing requiring 
porting is this library.

Complete documentation for the library can be found in the file:
  llvm/docs/SystemLibrary.html 
or at this URL:
  http://llvm.org/docs/SystemLibrary.html

While we recommend that you read the more detailed documentation, for the 
impatient, here's a high level summary of the library's requirements.

 1. No system header files are to be exposed through the interface.
 2. Std C++ and Std C header files are okay to be exposed through the interface.
 3. No exposed system-specific functions.
 4. No exposed system-specific data.
 5. Data in lib/System classes must use only simple C++ intrinsic types.
 6. Errors are handled by throwing std::string *only*.
 7. Library must not throw any exceptions except std::string.
 8. Interface functions must not have throw() specifications.
 9. No duplicate function impementations are permitted within an operating
    system class.

To accomplish these requirements, the library has numerous design criteria that 
must be satisfied. Here's a high level summary of the library's design criteria:

 1. No unused functionality (only what LLVM needs)
 2. High-Level Interfaces
 3. Use Opaque Classes
 4. Common Implementations</a></li>
 5. Multiple Implementations</a></li>
 6. Minimize Memory Allocation</a></li>
 7. No Virtual Methods