llvm-6502/lib/System
Reid Kleckner 10b4fc552f Re-committing r76828 with the JIT memory manager changes now that the build
bots like the BumpPtrAllocator changes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76902 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-23 21:46:56 +00:00
..
Unix Re-committing r76828 with the JIT memory manager changes now that the build 2009-07-23 21:46:56 +00:00
Win32 Re-committing r76828 with the JIT memory manager changes now that the build 2009-07-23 21:46:56 +00:00
Alarm.cpp
Atomic.cpp Add atomic multiply and divide operations, built on top of CompareAndSwap. 2009-06-23 21:19:04 +00:00
CMakeLists.txt Lexically order files in CMakeLists.txt files. 2009-07-15 21:08:16 +00:00
Disassembler.cpp hasDisassembler should return false if disassembler isn't available. 2008-11-04 06:09:38 +00:00
DynamicLibrary.cpp Eliminate the static constructors and locks from DynamicLibrary.cpp. 2009-07-07 18:17:07 +00:00
Errno.cpp Oops, I #included errno.h from inside the llvm::sys namespace. 2009-07-06 16:50:27 +00:00
Host.cpp
IncludeFile.cpp
LICENSE.TXT
Makefile Removed trailing whitespace from Makefiles. 2009-01-09 16:44:42 +00:00
Memory.cpp ARM / Mac OS X also wants to invalidate icache after jitting. 2008-11-14 02:33:17 +00:00
Mutex.cpp Insert a SmartMutex templated class into the class hierarchy, which takes a template parameter specifying whether this mutex 2009-06-18 17:53:17 +00:00
Path.cpp Improve sys::Path::makeAbsolute on Win32. 2009-07-12 20:23:56 +00:00
Process.cpp
Program.cpp Remove duplication in Program::Execute{And,No}Wait. 2009-07-18 21:43:12 +00:00
README.txt
RWMutex.cpp Workaround for an... interesting bug in Darwin's pthread_rwlock_init. 2009-06-20 00:32:27 +00:00
Signals.cpp
Threading.cpp No need to double-include config.h 2009-07-06 21:24:37 +00:00
ThreadLocal.cpp Try again at making this work on OpenBSD. 2009-07-01 16:19:23 +00:00
TimeValue.cpp

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