llvm-project/llvm/lib/Support
Ben Dunbobbin ac6a5aab45 [Support] env vars with empty values on windows
An environment variable can be in one of three states:

1. undefined.
2. defined with a non-empty value.
3. defined but with an empty value.

The windows implementation did not support case 3
(it was not handling errors). The Linux implementation
is already correct.

Differential Revision: https://reviews.llvm.org/D36394

llvm-svn: 311174
2017-08-18 16:55:44 +00:00
..
Unix [Support] Remove getPathFromOpenFD, it was unused 2017-08-04 17:43:49 +00:00
Windows [Support] env vars with empty values on windows 2017-08-18 16:55:44 +00:00
AMDGPUCodeObjectMetadata.cpp Fix ODR violations due to abuse of LLVM_YAML_IS_(FLOW_)?SEQUENCE_VECTOR 2017-06-30 20:56:57 +00:00
APFloat.cpp [APFloat] Move the integerPartWidth constant into APFloatBase. Remove integerPart typedef at file scope and just use the one in APFloatBase everywhere. NFC 2017-06-18 18:15:41 +00:00
APInt.cpp [APInt] Move the single word cases of countTrailingZeros and countLeadingOnes inline for consistency with countTrailingOnes and countLeadingZeros. NFCI 2017-06-23 20:28:45 +00:00
APSInt.cpp
ARMAttributeParser.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ARMBuildAttrs.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ARMWinEH.cpp
Allocator.cpp
Atomic.cpp Fix llvm-for-windows-on-linux build after LLVM r272701. 2017-08-03 20:10:47 +00:00
BinaryStreamError.cpp [Support] Move Stream library from MSF -> Support. 2017-03-02 20:52:51 +00:00
BinaryStreamReader.cpp Add a BinarySubstreamRef, and a method to read one. 2017-06-23 16:38:40 +00:00
BinaryStreamRef.cpp [BinaryStream] Reduce the amount of boiler plate needed to use. 2017-05-17 20:23:31 +00:00
BinaryStreamWriter.cpp Fix buildbots. 2017-06-16 02:42:33 +00:00
BlockFrequency.cpp
BranchProbability.cpp Cleanup dump() functions. 2017-01-28 02:02:38 +00:00
CMakeLists.txt [KnownBits][ValueTracking] Move the math for calculating known bits for add/sub into a static method in KnownBits object 2017-08-08 16:29:35 +00:00
COM.cpp
COPYRIGHT.regex
CachePruning.cpp Fix a misleading indentation warning. 2017-06-23 17:17:47 +00:00
Chrono.cpp Make naming in Host.h in line with coding standards. 2017-03-31 13:06:40 +00:00
CommandLine.cpp Fix minor typo introduced in r276404 2017-07-12 01:15:46 +00:00
Compression.cpp Recommit r292214 "[Support/Compression] - Change zlib API to return Error instead of custom status" 2017-01-17 15:45:07 +00:00
ConvertUTF.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ConvertUTFWrapper.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
CrashRecoveryContext.cpp Re-land r303274: "[CrashRecovery] Use SEH __try instead of VEH when available" 2017-05-17 18:16:17 +00:00
DAGDeltaAlgorithm.cpp
DataExtractor.cpp [DWARF] Support for DW_FORM_strx3 and complete support for DW_FORM_strx{1,2,4} 2017-06-21 19:37:44 +00:00
Debug.cpp Attempt to fix build bot after r290597 2016-12-27 10:24:58 +00:00
DebugCounter.cpp Hide dbgs() stream for when built with -fmodules. 2017-06-14 19:16:22 +00:00
DeltaAlgorithm.cpp
DynamicLibrary.cpp Allow clients to specify search order of DynamicLibraries. 2017-07-12 21:22:45 +00:00
Errno.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
Error.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ErrorHandling.cpp Defeat a GCC -Wunused-result warning 2017-07-19 15:03:38 +00:00
FileOutputBuffer.cpp Make FileOutputBuffer fail early if you pass a directory. 2017-03-13 22:19:05 +00:00
FileUtilities.cpp
FoldingSet.cpp Support, IR, ADT: Check nullptr after allocation with malloc/realloc or calloc 2017-07-20 01:30:39 +00:00
FormatVariadic.cpp [Support] Introduce llvm::formatv() function. 2016-11-11 23:57:40 +00:00
FormattedStream.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
GlobPattern.cpp [Support/GlobPattern] - Do not crash when pattern has characters with int value < 0. 2017-07-31 09:26:50 +00:00
GraphWriter.cpp [ProfileData, Support] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC). 2017-06-21 23:19:47 +00:00
Hashing.cpp
Host.cpp [X86] Improve the unknown stepping support for Intel CPUs in getHostCPUName 2017-07-27 03:26:52 +00:00
IntEqClasses.cpp
IntervalMap.cpp
JamCRC.cpp
KnownBits.cpp [KnownBits][ValueTracking] Move the math for calculating known bits for add/sub into a static method in KnownBits object 2017-08-08 16:29:35 +00:00
LEB128.cpp
LLVMBuild.txt
LineIterator.cpp
Locale.cpp
LockFileManager.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
LowLevelType.cpp [GlobalISel] Support vector-of-pointers in LLT 2017-04-19 07:23:57 +00:00
MD5.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ManagedStatic.cpp Revamp llvm::once_flag to be closer to std::once_flag 2017-02-05 21:13:06 +00:00
MathExtras.cpp
Memory.cpp
MemoryBuffer.cpp Recommit "[Support] Add RetryAfterSignal helper function" 2017-06-29 13:15:31 +00:00
Mutex.cpp [Support] - Add bad alloc error handler for handling allocation malfunctions 2017-07-11 16:45:30 +00:00
NativeFormatting.cpp Remove dead variable Len. 2017-01-04 19:47:10 +00:00
Options.cpp
Parallel.cpp Fix -DLLVM_ENABLE_THREADS=OFF build after r302748 2017-05-11 15:32:47 +00:00
Path.cpp [Path] Sink predicate computations to their uses. NFCI. 2017-08-09 22:06:32 +00:00
PluginLoader.cpp
PrettyStackTrace.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
Process.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
Program.cpp
README.txt.system
RWMutex.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
RandomNumberGenerator.cpp
Regex.cpp Add const to a const method. NFC 2017-04-18 01:04:05 +00:00
SHA1.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ScaledNumber.cpp Replace APFloatBase static fltSemantics data members with getter functions 2016-12-14 11:57:17 +00:00
ScopedPrinter.cpp [llvm-pdbdump] Allow printing only a portion of a stream. 2017-04-28 00:43:38 +00:00
Signals.cpp bugpoint: disabling symbolication of bugpoint-executed programs 2017-06-09 07:29:03 +00:00
SmallPtrSet.cpp Support, IR, ADT: Check nullptr after allocation with malloc/realloc or calloc 2017-07-20 01:30:39 +00:00
SmallVector.cpp Support, IR, ADT: Check nullptr after allocation with malloc/realloc or calloc 2017-07-20 01:30:39 +00:00
SourceMgr.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
SpecialCaseList.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
Statistic.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
StringExtras.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
StringMap.cpp Support, IR, ADT: Check nullptr after allocation with malloc/realloc or calloc 2017-07-20 01:30:39 +00:00
StringPool.cpp
StringRef.cpp [Support] Add StringRef::getAsDouble. 2017-02-14 19:06:37 +00:00
StringSaver.cpp
SystemUtils.cpp
TarWriter.cpp TarWriter: Fix a bug in Ustar header. 2017-01-09 22:55:00 +00:00
TargetParser.cpp [ARM][AArch64] ARMv8.3-A enablement 2017-08-10 09:41:00 +00:00
TargetRegistry.cpp Allow VersionPrinter to print to arbitrary raw_ostreams 2017-06-06 21:54:04 +00:00
ThreadLocal.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ThreadPool.cpp Support: Remove MSVC 2013 workarounds in ThreadPool class. 2017-06-14 00:36:21 +00:00
Threading.cpp Try to fix thread name truncation on non-Windows. 2017-03-04 18:53:09 +00:00
Timer.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
ToolOutputFile.cpp
TrigramIndex.cpp Sort the remaining #include lines in include/... and lib/.... 2017-06-06 11:49:48 +00:00
Triple.cpp [ARM][AArch64] ARMv8.3-A enablement 2017-08-10 09:41:00 +00:00
Twine.cpp Cleanup dump() functions. 2017-01-28 02:02:38 +00:00
Unicode.cpp
Valgrind.cpp
Watchdog.cpp
YAMLParser.cpp [ProfileData, Support] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC). 2017-06-21 23:19:47 +00:00
YAMLTraits.cpp [YAMLTraits] Add filename support to yaml::Input 2017-07-17 11:41:30 +00:00
circular_raw_ostream.cpp
raw_os_ostream.cpp
raw_ostream.cpp [Support] Update comments about stdout, raw_fd_ostream, and outs() 2017-08-04 01:39:23 +00:00
regcclass.h
regcname.h
regcomp.c
regengine.inc
regerror.c
regex2.h
regex_impl.h
regexec.c
regfree.c
regstrlcpy.c
regutils.h
xxhash.cpp Revert r301487: Replace HashString algorithm with xxHash64 2017-04-26 23:15:10 +00:00

README.txt.system

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