llvm/lib/Support
Mehdi Amini 22706dc4c0 Add Cache Pruning support
Incremental LTO will usea cache to store object files.
This patch handles the pruning part of the cache, exposing
a few knobs:

- Pruning interval: the implementation keeps a "timestamp" file in the
  directory and will scan it only after a given interval since the
  last modification of the timestamp file. This is for performance
  purpose, we don't want to scan continuously the folder.
- Entry expiration: this is the time after which a file that hasn't
  been used is remove from the cache.
- Maximum size: expressed in percentage of the available disk space,
  it helps to avoid that we blow up the disk space.

http://reviews.llvm.org/D18422

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265209 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-02 03:28:26 +00:00
..
Unix Add disk_space() to llvm::fs 2016-04-01 00:18:08 +00:00
Windows Fix Windows build (typo in disk_space() implementation) 2016-04-01 00:52:05 +00:00
Allocator.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
APFloat.cpp APFloat: Fix signalling nans for scalbn 2016-03-23 23:51:45 +00:00
APInt.cpp Implement constant folding for bitreverse 2016-03-21 15:00:35 +00:00
APSInt.cpp ADT: Add a string APSInt constructor. 2015-06-23 18:22:10 +00:00
ARMBuildAttrs.cpp [ARM] Add DSP build attribute and extension targeting 2016-01-25 11:26:11 +00:00
ARMWinEH.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
Atomic.cpp
BlockFrequency.cpp Add - and -= operators to BlockFrequency using saturating arithmetic. 2015-10-12 18:34:00 +00:00
BranchProbability.cpp Annotate dump() methods with LLVM_DUMP_METHOD, addressing Richard Smith r259192 post commit comment. 2016-01-29 20:50:44 +00:00
CachePruning.cpp Add Cache Pruning support 2016-04-02 03:28:26 +00:00
circular_raw_ostream.cpp
CMakeLists.txt Add Cache Pruning support 2016-04-02 03:28:26 +00:00
COM.cpp
CommandLine.cpp [CMake] Add PACKAGE_VENDOR for customizing version output 2016-03-15 18:07:46 +00:00
Compression.cpp
ConvertUTF.c
ConvertUTFWrapper.cpp More UTF string conversion wrappers 2016-03-11 15:59:32 +00:00
COPYRIGHT.regex
CrashRecoveryContext.cpp Remove useless and unused CrashRecoveryContext::getBacktrace(). This function always returned an empty string. 2016-03-25 20:30:10 +00:00
DAGDeltaAlgorithm.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
DataExtractor.cpp
DataStream.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
Debug.cpp The --debug-only option now takes a comma separated list of debug types. 2016-01-12 10:23:13 +00:00
DeltaAlgorithm.cpp
Dwarf.cpp Macro debug info support in LLVM IR 2015-12-10 12:56:35 +00:00
DynamicLibrary.cpp Add more wrappers for symbol APIs to the C API. 2015-06-09 15:57:30 +00:00
Errno.cpp
Error.cpp Try to fix ODR violation of ErrorInfo::ID 2016-03-24 23:49:34 +00:00
ErrorHandling.cpp [Support] Make all Errors convertible to std::error_code. 2016-03-23 23:57:28 +00:00
FileOutputBuffer.cpp Remove temporary file on signal. 2015-09-18 15:17:53 +00:00
FileUtilities.cpp Remove uses of builtin comma operator. 2016-02-18 22:09:30 +00:00
FoldingSet.cpp [ADT] Teach FoldingSet to be movable. 2015-08-16 23:17:27 +00:00
FormattedStream.cpp
GraphWriter.cpp [Support] Reapply r245289 "Always wait for GraphViz before opening the viewer" 2015-09-18 10:56:30 +00:00
Hashing.cpp
Host.cpp Fix LLVM's handling and detection of skylake and cannonlake CPUs 2016-02-21 17:12:03 +00:00
IntEqClasses.cpp Remove uses of builtin comma operator. 2016-02-18 22:09:30 +00:00
IntervalMap.cpp
IntrusiveRefCntPtr.cpp
JamCRC.cpp [MC] Add support for generating COFF CRCs 2015-09-01 21:23:58 +00:00
LEB128.cpp
LineIterator.cpp
LLVMBuild.txt
Locale.cpp Add #include llvm-config.h to Locale.cpp which depends on LLVM_ON_WIN32. 2015-09-11 13:22:47 +00:00
LockFileManager.cpp Reapply "Use gethostuuid() on Mac to identify hosts for LockFileManager" 2015-06-29 22:16:39 +00:00
ManagedStatic.cpp Support: Clean up TSan annotations. 2015-08-18 22:31:24 +00:00
MathExtras.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
MD5.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
Memory.cpp
MemoryBuffer.cpp Fix undefined behavior when compiling in C++14 mode (with sized deletion 2016-02-04 01:21:16 +00:00
MemoryObject.cpp
Mutex.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
Options.cpp
Path.cpp Fix identify_magic() to check that a file that starts with MH_MAGIC is 2016-01-26 23:43:37 +00:00
PluginLoader.cpp
PrettyStackTrace.cpp Reorganize the C API headers to improve build times. 2015-12-18 01:46:52 +00:00
Process.cpp
Program.cpp
RandomNumberGenerator.cpp
raw_os_ostream.cpp
raw_ostream.cpp C++11 is required, remove some preprocessor checks for it 2016-03-28 11:13:03 +00:00
README.txt.system
regcclass.h
regcname.h
regcomp.c
regengine.inc
regerror.c
regex2.h
regex_impl.h
Regex.cpp
regexec.c
regfree.c
regstrlcpy.c
regutils.h
RWMutex.cpp Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) 2015-06-23 09:49:53 +00:00
ScaledNumber.cpp
SearchForAddressOfSpecialSymbol.cpp
SHA1.cpp Fix S390 big endian detection 2016-04-01 05:12:24 +00:00
Signals.cpp Appease hosts without HAVE_BACKTRACE nor ENABLE_BACKTRACES. 2015-11-08 09:45:06 +00:00
SmallPtrSet.cpp SmallPtrSet: Avoid initializing Array in the small case. 2016-02-15 21:38:42 +00:00
SmallVector.cpp [ADT] Assert that SmallVectorBase::grow_pod() successfully reallocates memory. 2015-06-09 09:47:46 +00:00
SourceMgr.cpp MIR Serialization: Connect the machine function analysis pass to the MIR parser. 2015-06-15 20:30:22 +00:00
SpecialCaseList.cpp
Statistic.cpp Simplify memory management with std::unique_ptr. 2015-12-16 22:28:34 +00:00
StreamingMemoryObject.cpp Support: Implement StreamingMemoryObject::getPointer 2016-03-27 23:00:59 +00:00
StringExtras.cpp
StringMap.cpp Adjust initial size in StringMap constructor to guarantee no grow() 2016-03-25 05:57:57 +00:00
StringPool.cpp
StringRef.cpp [MCParser] Accept uppercase radix variants 0X and 0B 2016-03-18 18:22:07 +00:00
StringSaver.cpp There is only one saver of strings. 2015-08-13 01:07:02 +00:00
SystemUtils.cpp
TargetParser.cpp Support: catch invalid accesses 2016-03-05 20:00:44 +00:00
TargetRegistry.cpp Don't mention a command line option in an error. 2016-01-28 22:55:45 +00:00
Threading.cpp
ThreadLocal.cpp
ThreadPool.cpp Fix MSVC build with LLVM_ENABLE_THREADS=OFF 2015-12-15 05:53:41 +00:00
Timer.cpp [Support] Allow multiple paired calls to {start,stop}Timer() 2015-12-22 17:36:17 +00:00
TimeValue.cpp Fix some Clang-tidy modernize warnings, other minor fixes. 2015-11-04 22:32:32 +00:00
ToolOutputFile.cpp
Triple.cpp Add AMDGPU related triple vendors/OSes 2016-02-13 01:56:21 +00:00
Twine.cpp Annotate dump() methods with LLVM_DUMP_METHOD, addressing Richard Smith r259192 post commit comment. 2016-01-29 20:50:44 +00:00
Unicode.cpp
Valgrind.cpp Add a missing include of cstddef needed for size_t. 2015-10-15 19:41:54 +00:00
Watchdog.cpp
YAMLParser.cpp Simplify users of StringRef::{l,r}trim (NFC) 2016-02-16 02:06:01 +00:00
YAMLTraits.cpp [YAMLTraits] Use StringRef::copy. No functionality change. 2015-08-05 14:16:38 +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
 5. Multiple Implementations
 6. Minimize Memory Allocation
 7. No Virtual Methods