From 6f36fa981a59461466e12e5056ba209d289b81b1 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Mon, 11 Jun 2012 15:37:55 +0000 Subject: Write llvm-tblgen backends as functions instead of sub-classes. The TableGenBackend base class doesn't do much, and will be removed completely soon. Patch by Sean Silva! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158311 91177308-0d34-0410-b5e6-96231b3b80d8 --- utils/TableGen/TableGenBackends.h | 78 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 utils/TableGen/TableGenBackends.h (limited to 'utils/TableGen/TableGenBackends.h') diff --git a/utils/TableGen/TableGenBackends.h b/utils/TableGen/TableGenBackends.h new file mode 100644 index 0000000000..2c00c40cfe --- /dev/null +++ b/utils/TableGen/TableGenBackends.h @@ -0,0 +1,78 @@ +//===- TableGenBackends.h - Declarations for LLVM TableGen Backends -------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains the declarations for all of the LLVM TableGen +// backends. A "TableGen backend" is just a function. See below for a +// precise description. +// +//===----------------------------------------------------------------------===// + + +// A TableGen backend is a function that looks like +// +// EmitFoo(RecordKeeper &RK, raw_ostream &OS /*, anything else you need */ ) +// +// What you do inside of that function is up to you, but it will usually +// involve generating C++ code to the provided raw_ostream. +// +// The RecordKeeper is just a top-level container for an in-memory +// representation of the data encoded in the TableGen file. What a TableGen +// backend does is walk around that in-memory representation and generate +// stuff based on the information it contains. +// +// The in-memory representation is a node-graph (think of it like JSON but +// with a richer ontology of types), where the nodes are subclasses of +// Record. The methods `getClass`, `getDef` are the basic interface to +// access the node-graph. RecordKeeper also provides a handy method +// `getAllDerivedDefinitions`. Consult "include/llvm/TableGen/Record.h" for +// the exact interfaces provided by Record's and RecordKeeper. +// +// A common pattern for TableGen backends is for the EmitFoo function to +// instantiate a class which holds some context for the generation process, +// and then have most of the work happen in that class's methods. This +// pattern partly has historical roots in the previous TableGen backend API +// that involved a class and an invocation like `FooEmitter(RK).run(OS)`. +// +// Remember to wrap private things in an anonymous namespace. For most +// backends, this means that the EmitFoo function is the only thing not in +// the anonymous namespace. + + +// FIXME: Reorganize TableGen so that build dependencies can be more +// accurately expressed. Currently, touching any of the emitters (or +// anything that they transitively depend on) causes everything dependent +// on TableGen to be rebuilt (this includes all the targets!). Perhaps have +// a standalone TableGen binary and have the backends be loadable modules +// of some sort; then the dependency could be expressed as being on the +// module, and all the modules would have a common dependency on the +// TableGen binary with as few dependencies as possible on the rest of +// LLVM. + + +namespace llvm { + +class raw_ostream; +class RecordKeeper; + +void EmitIntrinsics(RecordKeeper &RK, raw_ostream &OS, bool TargetOnly = false); +void EmitAsmMatcher(RecordKeeper &RK, raw_ostream &OS); +void EmitAsmWriter(RecordKeeper &RK, raw_ostream &OS); +void EmitCallingConv(RecordKeeper &RK, raw_ostream &OS); +void EmitCodeEmitter(RecordKeeper &RK, raw_ostream &OS); +void EmitDAGISel(RecordKeeper &RK, raw_ostream &OS); +void EmitDFAPacketizer(RecordKeeper &RK, raw_ostream &OS); +void EmitDisassembler(RecordKeeper &RK, raw_ostream &OS); +void EmitEnhancedDisassemblerInfo(RecordKeeper &RK, raw_ostream &OS); +void EmitFastISel(RecordKeeper &RK, raw_ostream &OS); +void EmitInstrInfo(RecordKeeper &RK, raw_ostream &OS); +void EmitPseudoLowering(RecordKeeper &RK, raw_ostream &OS); +void EmitRegisterInfo(RecordKeeper &RK, raw_ostream &OS); +void EmitSubtarget(RecordKeeper &RK, raw_ostream &OS); + +} // End llvm namespace -- cgit v1.2.3