1 //===- TableGenBackend.cpp - Utilities for TableGen Backends ----*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file provides useful services for TableGen backends... 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/TableGen/TableGenBackend.h" 14 #include "llvm/ADT/Twine.h" 15 #include "llvm/Support/CommandLine.h" 16 #include "llvm/Support/ManagedStatic.h" 17 #include "llvm/Support/Path.h" 18 #include "llvm/Support/raw_ostream.h" 19 #include <algorithm> 20 #include <cassert> 21 #include <cstddef> 22 23 using namespace llvm; 24 using namespace TableGen::Emitter; 25 26 const size_t MAX_LINE_LEN = 80U; 27 28 // CommandLine options of class type are not directly supported with some 29 // specific exceptions like std::string which are safe to copy. In our case, 30 // the `FnT` function_ref object is also safe to copy. So provide a 31 // specialization of `OptionValue` for `FnT` type that stores it as a copy. 32 // This is essentially similar to OptionValue<std::string> specialization for 33 // strings. 34 template <> struct cl::OptionValue<FnT> final : cl::OptionValueCopy<FnT> { 35 OptionValue() = default; 36 37 OptionValue(const FnT &V) { this->setValue(V); } 38 39 OptionValue<FnT> &operator=(const FnT &V) { 40 setValue(V); 41 return *this; 42 } 43 }; 44 45 namespace { 46 struct OptCreatorT { 47 static void *call() { 48 return new cl::opt<FnT>(cl::desc("Action to perform:")); 49 } 50 }; 51 } // namespace 52 53 static ManagedStatic<cl::opt<FnT>, OptCreatorT> CallbackFunction; 54 55 Opt::Opt(StringRef Name, FnT CB, StringRef Desc, bool ByDefault) { 56 if (ByDefault) 57 CallbackFunction->setInitialValue(CB); 58 CallbackFunction->getParser().addLiteralOption(Name, CB, Desc); 59 } 60 61 /// Apply callback specified on the command line. Returns true if no callback 62 /// was applied. 63 bool llvm::TableGen::Emitter::ApplyCallback(const RecordKeeper &Records, 64 raw_ostream &OS) { 65 FnT Fn = CallbackFunction->getValue(); 66 if (!Fn) 67 return true; 68 Fn(Records, OS); 69 return false; 70 } 71 72 static void printLine(raw_ostream &OS, const Twine &Prefix, char Fill, 73 StringRef Suffix) { 74 size_t Pos = (size_t)OS.tell(); 75 assert((Prefix.str().size() + Suffix.size() <= MAX_LINE_LEN) && 76 "header line exceeds max limit"); 77 OS << Prefix; 78 for (size_t i = (size_t)OS.tell() - Pos, e = MAX_LINE_LEN - Suffix.size(); 79 i < e; ++i) 80 OS << Fill; 81 OS << Suffix << '\n'; 82 } 83 84 void llvm::emitSourceFileHeader(StringRef Desc, raw_ostream &OS, 85 const RecordKeeper &Record) { 86 printLine(OS, "/*===- TableGen'erated file ", '-', "*- C++ -*-===*\\"); 87 StringRef Prefix("|* "); 88 StringRef Suffix(" *|"); 89 printLine(OS, Prefix, ' ', Suffix); 90 size_t PSLen = Prefix.size() + Suffix.size(); 91 assert(PSLen < MAX_LINE_LEN); 92 size_t Pos = 0U; 93 do { 94 size_t Length = std::min(Desc.size() - Pos, MAX_LINE_LEN - PSLen); 95 printLine(OS, Prefix + Desc.substr(Pos, Length), ' ', Suffix); 96 Pos += Length; 97 } while (Pos < Desc.size()); 98 printLine(OS, Prefix, ' ', Suffix); 99 printLine(OS, Prefix + "Automatically generated file, do not edit!", ' ', 100 Suffix); 101 102 // Print the filename of source file. 103 if (!Record.getInputFilename().empty()) 104 printLine( 105 OS, Prefix + "From: " + sys::path::filename(Record.getInputFilename()), 106 ' ', Suffix); 107 printLine(OS, Prefix, ' ', Suffix); 108 printLine(OS, "\\*===", '-', "===*/"); 109 OS << '\n'; 110 } 111