CodeExpander.cpp
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//===- CodeExpander.cpp - Expand variables in a string --------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
/// \file Expand the variables in a string.
//
//===----------------------------------------------------------------------===//
#include "CodeExpander.h"
#include "CodeExpansions.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Error.h"
using namespace llvm;
void CodeExpander::emit(raw_ostream &OS) const {
StringRef Current = Code;
while (!Current.empty()) {
size_t Pos = Current.find_first_of("$\n\\");
if (Pos == StringRef::npos) {
OS << Current;
Current = "";
continue;
}
OS << Current.substr(0, Pos);
Current = Current.substr(Pos);
if (Current.startswith("\n")) {
OS << "\n" << Indent;
Current = Current.drop_front(1);
continue;
}
if (Current.startswith("\\$") || Current.startswith("\\\\")) {
OS << Current[1];
Current = Current.drop_front(2);
continue;
}
if (Current.startswith("\\")) {
Current = Current.drop_front(1);
continue;
}
if (Current.startswith("${")) {
StringRef StartVar = Current;
Current = Current.drop_front(2);
StringRef Var;
std::tie(Var, Current) = Current.split("}");
// Warn if we split because no terminator was found.
StringRef EndVar = StartVar.drop_front(2 /* ${ */ + Var.size());
if (EndVar.empty()) {
size_t LocOffset = StartVar.data() - Code.data();
PrintWarning(
Loc.size() > 0 && Loc[0].isValid()
? SMLoc::getFromPointer(Loc[0].getPointer() + LocOffset)
: SMLoc(),
"Unterminated expansion");
}
auto ValueI = Expansions.find(Var);
if (ValueI == Expansions.end()) {
size_t LocOffset = StartVar.data() - Code.data();
PrintError(Loc.size() > 0 && Loc[0].isValid()
? SMLoc::getFromPointer(Loc[0].getPointer() + LocOffset)
: SMLoc(),
"Attempting to expand an undeclared variable " + Var);
}
if (ShowExpansions)
OS << "/*$" << Var << "{*/";
OS << Expansions.lookup(Var);
if (ShowExpansions)
OS << "/*}*/";
continue;
}
size_t LocOffset = Current.data() - Code.data();
PrintWarning(Loc.size() > 0 && Loc[0].isValid()
? SMLoc::getFromPointer(Loc[0].getPointer() + LocOffset)
: SMLoc(),
"Assuming missing escape character");
OS << "$";
Current = Current.drop_front(1);
}
}