[NFC] Rename `FixedLenDecoderEmitter` as `DecoderEmitter`

[0x59616e]

Summary

Since now we are able to handle both fixed length & variable
length instructions.

[0x59616e]

Rename the class name.

[RKSimon]

No objections from me @myhsu ? Just a few minors to address.

There's some clang formatting that needs to be done since you've changed the length :-) of the class name

llvm/utils/TableGen/DecoderEmitter.cpp

2699

clang format

llvm/utils/TableGen/DisassemblerEmitter.cpp

103 ↗

(On Diff #421717)

clang format

130 ↗

(On Diff #421717)

Raise a bug to track this?

147 ↗

(On Diff #421717)

clang format

153 ↗

(On Diff #421717)

clang format

[0x59616e]

Thanks !

I've noticed the clang-format problem. The weird thing is, It happened after I rename this file, before I change anything in it. That makes me confusing. It should have not happened because I only change the file name.

So I want to take some time looking into it.

llvm/utils/TableGen/DisassemblerEmitter.cpp

130 ↗

(On Diff #421717)

I change this TODO just for reflecting the status of this decoder emitter to avoid confusing someone.

Resolving this means we need to deploy our varlen encoding infra onto webassembly backend. I don't know whether this is a good idea since this is a non-trivial work I guess.

[0x59616e]

I know what is going on.

clang-format only modifies the diff part. Since now I rename the file,

the whole file will be checked and modified by clang-format.

[craig.topper]

llvm/utils/TableGen/DecoderEmitter.cpp

485

Please don't reformat lines that aren't affected by your change. Use clang-format-diff.py

[myhsu]

LGTM, please resolve the formatting issues though

llvm/utils/TableGen/DisassemblerEmitter.cpp

130 ↗

(On Diff #421717)

I prefer creating a bug for this (and ping the wasm backend maintainer) but leave the comment unchanged

[0x59616e]

address format issue

[0x59616e]

Revert the TODO suggested my myhsu

[0x59616e]

continue addressing formating issues

llvm/utils/TableGen/CMakeLists.txt

add_tablegen(llvm-tblgen LLVM
   CodeGenRegisters.cpp
   CodeGenSchedule.cpp
   CodeGenTarget.cpp
   DAGISelEmitter.cpp
   DAGISelMatcherEmitter.cpp
   DAGISelMatcherGen.cpp
   DAGISelMatcherOpt.cpp
   DAGISelMatcher.cpp
+  DecoderEmitter.cpp
   DFAEmitter.cpp
   DFAPacketizerEmitter.cpp
   DirectiveEmitter.cpp
   DisassemblerEmitter.cpp
   ExegesisEmitter.cpp
   FastISelEmitter.cpp
-  FixedLenDecoderEmitter.cpp
   GICombinerEmitter.cpp
   GlobalISelEmitter.cpp
   InfoByHwMode.cpp
   InstrInfoEmitter.cpp
   InstrDocsEmitter.cpp
   IntrinsicEmitter.cpp
   OptEmitter.cpp
   OptParserEmitter.cpp

llvm/utils/TableGen/DecoderEmitter.cpp

-//===------------ FixedLenDecoderEmitter.cpp - Decoder Generator ----------===//
+//===------------ DecoderEmitter.cpp - Decoder Generator ----------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // It contains the tablegen backend that emits the decoder functions for
protected:
   // Returns false if there exists any uninitialized bit value in the range.
   // Returns true, otherwise.
   bool fieldFromInsn(uint64_t &Field, insn_t &Insn, unsigned StartBit,
                      unsigned NumBits) const;
 
   /// dumpFilterArray - dumpFilterArray prints out debugging info for the given
   /// filter array as a series of chars.
   void dumpFilterArray(raw_ostream &o,
                        const std::vector<bit_value_t> & filter) const;
 
   /// dumpStack - dumpStack traverses the filter chooser chain and calls
   /// dumpFilterArray on each filter chooser up to the top level one.
   void dumpStack(raw_ostream &o, const char *prefix) const;
 
   Filter &bestFilter() {
     assert(BestIndex != -1 && "BestIndex not set");
     return Filters[BestIndex];

 namespace llvm {
 
 void EmitFixedLenDecoder(RecordKeeper &RK, raw_ostream &OS,
                          const std::string &PredicateNamespace,
                          const std::string &GPrefix,
                          const std::string &GPostfix, const std::string &ROK,
                          const std::string &RFail, const std::string &L) {
   FixedLenDecoderEmitter(RK, PredicateNamespace, GPrefix, GPostfix,
                          ROK, RFail, L).run(OS);
 }
 
 } // end namespace llvm

llvm/utils/gn/secondary/llvm/utils/TableGen/BUILD.gn

sources = [
     "CodeGenSchedule.cpp",
     "CodeGenTarget.cpp",
     "CompressInstEmitter.cpp",
     "DAGISelEmitter.cpp",
     "DAGISelMatcher.cpp",
     "DAGISelMatcherEmitter.cpp",
     "DAGISelMatcherGen.cpp",
     "DAGISelMatcherOpt.cpp",
+    "DecoderEmitter.cpp",
     "DFAEmitter.cpp",
     "DFAPacketizerEmitter.cpp",
     "DirectiveEmitter.cpp",
     "DisassemblerEmitter.cpp",
     "ExegesisEmitter.cpp",
     "FastISelEmitter.cpp",
-    "FixedLenDecoderEmitter.cpp",
     "GICombinerEmitter.cpp",
     "GlobalISelEmitter.cpp",
     "InfoByHwMode.cpp",
     "InstrDocsEmitter.cpp",
     "InstrInfoEmitter.cpp",
     "IntrinsicEmitter.cpp",
     "OptEmitter.cpp",
     "OptParserEmitter.cpp",