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Diffstat (limited to 'utils/TableGen/StringMatcher.cpp')
-rw-r--r-- | utils/TableGen/StringMatcher.cpp | 149 |
1 files changed, 0 insertions, 149 deletions
diff --git a/utils/TableGen/StringMatcher.cpp b/utils/TableGen/StringMatcher.cpp deleted file mode 100644 index 6aedcbf..0000000 --- a/utils/TableGen/StringMatcher.cpp +++ /dev/null @@ -1,149 +0,0 @@ -//===- StringMatcher.cpp - Generate a matcher for input strings -----------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements the StringMatcher class. -// -//===----------------------------------------------------------------------===// - -#include "StringMatcher.h" -#include "llvm/Support/raw_ostream.h" -#include <map> -using namespace llvm; - -/// FindFirstNonCommonLetter - Find the first character in the keys of the -/// string pairs that is not shared across the whole set of strings. All -/// strings are assumed to have the same length. -static unsigned -FindFirstNonCommonLetter(const std::vector<const - StringMatcher::StringPair*> &Matches) { - assert(!Matches.empty()); - for (unsigned i = 0, e = Matches[0]->first.size(); i != e; ++i) { - // Check to see if letter i is the same across the set. - char Letter = Matches[0]->first[i]; - - for (unsigned str = 0, e = Matches.size(); str != e; ++str) - if (Matches[str]->first[i] != Letter) - return i; - } - - return Matches[0]->first.size(); -} - -/// EmitStringMatcherForChar - Given a set of strings that are known to be the -/// same length and whose characters leading up to CharNo are the same, emit -/// code to verify that CharNo and later are the same. -/// -/// \return - True if control can leave the emitted code fragment. -bool StringMatcher:: -EmitStringMatcherForChar(const std::vector<const StringPair*> &Matches, - unsigned CharNo, unsigned IndentCount) const { - assert(!Matches.empty() && "Must have at least one string to match!"); - std::string Indent(IndentCount*2+4, ' '); - - // If we have verified that the entire string matches, we're done: output the - // matching code. - if (CharNo == Matches[0]->first.size()) { - assert(Matches.size() == 1 && "Had duplicate keys to match on"); - - // If the to-execute code has \n's in it, indent each subsequent line. - StringRef Code = Matches[0]->second; - - std::pair<StringRef, StringRef> Split = Code.split('\n'); - OS << Indent << Split.first << "\t // \"" << Matches[0]->first << "\"\n"; - - Code = Split.second; - while (!Code.empty()) { - Split = Code.split('\n'); - OS << Indent << Split.first << "\n"; - Code = Split.second; - } - return false; - } - - // Bucket the matches by the character we are comparing. - std::map<char, std::vector<const StringPair*> > MatchesByLetter; - - for (unsigned i = 0, e = Matches.size(); i != e; ++i) - MatchesByLetter[Matches[i]->first[CharNo]].push_back(Matches[i]); - - - // If we have exactly one bucket to match, see how many characters are common - // across the whole set and match all of them at once. - if (MatchesByLetter.size() == 1) { - unsigned FirstNonCommonLetter = FindFirstNonCommonLetter(Matches); - unsigned NumChars = FirstNonCommonLetter-CharNo; - - // Emit code to break out if the prefix doesn't match. - if (NumChars == 1) { - // Do the comparison with if (Str[1] != 'f') - // FIXME: Need to escape general characters. - OS << Indent << "if (" << StrVariableName << "[" << CharNo << "] != '" - << Matches[0]->first[CharNo] << "')\n"; - OS << Indent << " break;\n"; - } else { - // Do the comparison with if (Str.substr(1, 3) != "foo"). - // FIXME: Need to escape general strings. - OS << Indent << "if (" << StrVariableName << ".substr(" << CharNo << ", " - << NumChars << ") != \""; - OS << Matches[0]->first.substr(CharNo, NumChars) << "\")\n"; - OS << Indent << " break;\n"; - } - - return EmitStringMatcherForChar(Matches, FirstNonCommonLetter, IndentCount); - } - - // Otherwise, we have multiple possible things, emit a switch on the - // character. - OS << Indent << "switch (" << StrVariableName << "[" << CharNo << "]) {\n"; - OS << Indent << "default: break;\n"; - - for (std::map<char, std::vector<const StringPair*> >::iterator LI = - MatchesByLetter.begin(), E = MatchesByLetter.end(); LI != E; ++LI) { - // TODO: escape hard stuff (like \n) if we ever care about it. - OS << Indent << "case '" << LI->first << "':\t // " - << LI->second.size() << " string"; - if (LI->second.size() != 1) OS << 's'; - OS << " to match.\n"; - if (EmitStringMatcherForChar(LI->second, CharNo+1, IndentCount+1)) - OS << Indent << " break;\n"; - } - - OS << Indent << "}\n"; - return true; -} - - -/// Emit - Top level entry point. -/// -void StringMatcher::Emit(unsigned Indent) const { - // If nothing to match, just fall through. - if (Matches.empty()) return; - - // First level categorization: group strings by length. - std::map<unsigned, std::vector<const StringPair*> > MatchesByLength; - - for (unsigned i = 0, e = Matches.size(); i != e; ++i) - MatchesByLength[Matches[i].first.size()].push_back(&Matches[i]); - - // Output a switch statement on length and categorize the elements within each - // bin. - OS.indent(Indent*2+2) << "switch (" << StrVariableName << ".size()) {\n"; - OS.indent(Indent*2+2) << "default: break;\n"; - - for (std::map<unsigned, std::vector<const StringPair*> >::iterator LI = - MatchesByLength.begin(), E = MatchesByLength.end(); LI != E; ++LI) { - OS.indent(Indent*2+2) << "case " << LI->first << ":\t // " - << LI->second.size() - << " string" << (LI->second.size() == 1 ? "" : "s") << " to match.\n"; - if (EmitStringMatcherForChar(LI->second, 0, Indent)) - OS.indent(Indent*2+4) << "break;\n"; - } - - OS.indent(Indent*2+2) << "}\n"; -} |