81 lines · cpp
1//===- CodeExpander.cpp - Expand variables in a string --------------------===//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-exception6//7//===----------------------------------------------------------------------===//8//9/// \file Expand the variables in a string.10//11//===----------------------------------------------------------------------===//12 13#include "CodeExpander.h"14#include "CodeExpansions.h"15#include "llvm/Support/raw_ostream.h"16#include "llvm/TableGen/Error.h"17 18using namespace llvm;19 20void CodeExpander::emit(raw_ostream &OS) const {21 StringRef Current = Code;22 23 while (!Current.empty()) {24 size_t Pos = Current.find_first_of("$\n\\");25 if (Pos == StringRef::npos) {26 OS << Current;27 Current = "";28 continue;29 }30 31 OS << Current.substr(0, Pos);32 Current = Current.substr(Pos);33 34 if (Current.consume_front("\n")) {35 OS << "\n" << Indent;36 continue;37 }38 39 if (Current.starts_with("\\$") || Current.starts_with("\\\\")) {40 OS << Current[1];41 Current = Current.drop_front(2);42 continue;43 }44 45 if (Current.consume_front("\\"))46 continue;47 48 if (Current.starts_with("${")) {49 StringRef StartVar = Current;50 Current = Current.drop_front(2);51 StringRef Var;52 std::tie(Var, Current) = Current.split("}");53 54 // Warn if we split because no terminator was found.55 StringRef EndVar = StartVar.drop_front(2 /* ${ */ + Var.size());56 if (EndVar.empty()) {57 PrintWarning(Loc, "Unterminated expansion '${" + Var + "'");58 PrintNote("Code: [{" + Code + "}]");59 }60 61 auto ValueI = Expansions.find(Var);62 if (ValueI == Expansions.end()) {63 PrintError(Loc,64 "Attempt to expand an undeclared variable '" + Var + "'");65 PrintNote("Code: [{" + Code + "}]");66 }67 if (ShowExpansions)68 OS << "/*$" << Var << "{*/";69 OS << Expansions.lookup(Var);70 if (ShowExpansions)71 OS << "/*}*/";72 continue;73 }74 75 PrintWarning(Loc, "Assuming missing escape character: \\$");76 PrintNote("Code: [{" + Code + "}]");77 OS << "$";78 Current = Current.drop_front(1);79 }80}81