# Welcome to Flang's documentation
Flang is LLVM's Fortran frontend that can be found
[here](https://github.com/llvm/llvm-project/tree/main/flang). It is often
referred to as "LLVM Flang" to differentiate itself from ["Classic
Flang"](https://github.com/flang-compiler/flang) - these are two separate and
independent Fortran compilers. LLVM Flang is under active development. While it
is capable of generating executables for a number of examples, some
functionality is still missing. See [Getting Involved](GettingInvolved) for tips
on how to get in touch with us and to learn more about the current status.
```{eval-rst}
.. toctree::
:titlesonly:
ReleaseNotes
```
# Contributing to Flang
```{eval-rst}
.. toctree::
:titlesonly:
C++17
C++style
DesignGuideline
FortranForCProgrammers
GettingInvolved
GettingStarted
ImplementingASemanticCheck
PullRequestChecklist
```
# Design Documents
```{eval-rst}
.. toctree::
:titlesonly:
Aliasing
AliasingAnalysisFIR
ArrayComposition
AssumedRank
BijectiveInternalNameUniquing
Calls
Character
ComplexOperations
ControlFlowGraph
DebugGeneration
Directives
DoConcurrent
Extensions
F202X
FIRArrayOperations
FIRLangRef
FlangCommandLineReference
FlangDriver
FortranFeatureHistory
FortranIR
FortranLLVMTestSuite
HighLevelFIR
IORuntimeInternals
InternalProcedureTrampolines
Intrinsics
IntrinsicTypes
LabelResolution
ModFiles
OpenACC
OpenACC-descriptor-management.md
OpenMP-4.5-grammar.md
OpenMP-declare-target
OpenMP-descriptor-management
OpenMP-semantics
OptionComparison
Overview
ParameterizedDerivedTypes
ParserCombinators
Parsing
PolymorphicEntities
Preprocessing
ProcedurePointer
RuntimeDescriptor
RuntimeEnvironment
RuntimeTypeInfo
Semantics
f2018-grammar.md
fstack-arrays
Real16MathSupport
```
# Indices and tables
```{eval-rst}
* :ref:`genindex`
* :ref:`search`
```