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      1 //===- TableGenBackends.h - Declarations for LLVM TableGen Backends -------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file contains the declarations for all of the LLVM TableGen
     11 // backends. A "TableGen backend" is just a function. See below for a
     12 // precise description.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 
     17 // A TableGen backend is a function that looks like
     18 //
     19 //    EmitFoo(RecordKeeper &RK, raw_ostream &OS /*, anything else you need */ )
     20 //
     21 // What you do inside of that function is up to you, but it will usually
     22 // involve generating C++ code to the provided raw_ostream.
     23 //
     24 // The RecordKeeper is just a top-level container for an in-memory
     25 // representation of the data encoded in the TableGen file. What a TableGen
     26 // backend does is walk around that in-memory representation and generate
     27 // stuff based on the information it contains.
     28 //
     29 // The in-memory representation is a node-graph (think of it like JSON but
     30 // with a richer ontology of types), where the nodes are subclasses of
     31 // Record. The methods `getClass`, `getDef` are the basic interface to
     32 // access the node-graph.  RecordKeeper also provides a handy method
     33 // `getAllDerivedDefinitions`. Consult "include/llvm/TableGen/Record.h" for
     34 // the exact interfaces provided by Record's and RecordKeeper.
     35 //
     36 // A common pattern for TableGen backends is for the EmitFoo function to
     37 // instantiate a class which holds some context for the generation process,
     38 // and then have most of the work happen in that class's methods. This
     39 // pattern partly has historical roots in the previous TableGen backend API
     40 // that involved a class and an invocation like `FooEmitter(RK).run(OS)`.
     41 //
     42 // Remember to wrap private things in an anonymous namespace. For most
     43 // backends, this means that the EmitFoo function is the only thing not in
     44 // the anonymous namespace.
     45 
     46 
     47 // FIXME: Reorganize TableGen so that build dependencies can be more
     48 // accurately expressed. Currently, touching any of the emitters (or
     49 // anything that they transitively depend on) causes everything dependent
     50 // on TableGen to be rebuilt (this includes all the targets!). Perhaps have
     51 // a standalone TableGen binary and have the backends be loadable modules
     52 // of some sort; then the dependency could be expressed as being on the
     53 // module, and all the modules would have a common dependency on the
     54 // TableGen binary with as few dependencies as possible on the rest of
     55 // LLVM.
     56 
     57 
     58 namespace llvm {
     59 
     60 class raw_ostream;
     61 class RecordKeeper;
     62 
     63 void EmitIntrinsics(RecordKeeper &RK, raw_ostream &OS, bool TargetOnly = false);
     64 void EmitAsmMatcher(RecordKeeper &RK, raw_ostream &OS);
     65 void EmitAsmWriter(RecordKeeper &RK, raw_ostream &OS);
     66 void EmitCallingConv(RecordKeeper &RK, raw_ostream &OS);
     67 void EmitCodeEmitter(RecordKeeper &RK, raw_ostream &OS);
     68 void EmitDAGISel(RecordKeeper &RK, raw_ostream &OS);
     69 void EmitDFAPacketizer(RecordKeeper &RK, raw_ostream &OS);
     70 void EmitDisassembler(RecordKeeper &RK, raw_ostream &OS);
     71 void EmitFastISel(RecordKeeper &RK, raw_ostream &OS);
     72 void EmitInstrInfo(RecordKeeper &RK, raw_ostream &OS);
     73 void EmitPseudoLowering(RecordKeeper &RK, raw_ostream &OS);
     74 void EmitRegisterInfo(RecordKeeper &RK, raw_ostream &OS);
     75 void EmitSubtarget(RecordKeeper &RK, raw_ostream &OS);
     76 void EmitMapTable(RecordKeeper &RK, raw_ostream &OS);
     77 void EmitOptParser(RecordKeeper &RK, raw_ostream &OS);
     78 
     79 } // End llvm namespace
     80