llvm-mirror/lib/System
2010-05-08 02:10:34 +00:00
..
Unix Add llvm::sys::RunInterruptHandlers(), which runs the registered SIGINT cleanup 2010-05-08 02:10:34 +00:00
Win32 Add llvm::sys::RunInterruptHandlers(), which runs the registered SIGINT cleanup 2010-05-08 02:10:34 +00:00
Alarm.cpp
Atomic.cpp Fixes the Atomic implementation if compiled by MSVC compiler. 2009-12-07 05:29:59 +00:00
CMakeLists.txt Tell Valgrind when we modify already-executed machine code so it knows 2010-03-15 04:57:55 +00:00
Disassembler.cpp
DynamicLibrary.cpp Fix a bunch of namespace polution. 2010-04-15 17:08:50 +00:00
Errno.cpp
Host.cpp Stubs for getHostCPUFeatures API. This implements part of PR5389. 2010-01-19 21:26:05 +00:00
IncludeFile.cpp
Makefile mark some libraries that currently require RTTI. 2010-01-24 20:22:08 +00:00
Memory.cpp Tell Valgrind when we modify already-executed machine code so it knows 2010-03-15 04:57:55 +00:00
Mutex.cpp
Path.cpp Make Path use StringRef instead of std::string where possible. 2009-12-17 21:02:39 +00:00
Process.cpp
Program.cpp unnest from namespace. 2010-04-18 03:33:55 +00:00
README.txt
RWMutex.cpp
SearchForAddressOfSpecialSymbol.cpp Make clang bootstrap happier on OSX 10.5 by reducing the number of headers 2010-03-11 06:14:32 +00:00
Signals.cpp
Threading.cpp
ThreadLocal.cpp
TimeValue.cpp
Valgrind.cpp Tell Valgrind when we modify already-executed machine code so it knows 2010-03-15 04:57:55 +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 returning "true" and setting an optional std::string
 7. Library must not throw any exceptions, period.
 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