--- /dev/null
+//===-- llvm-mcmarkup.cpp - Parse the MC assembly markup tags -------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Example simple parser implementation for the MC assembly markup language.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/system_error.h"
+using namespace llvm;
+
+static cl::list<std::string>
+ InputFilenames(cl::Positional, cl::desc("<input files>"),
+ cl::ZeroOrMore);
+static cl::opt<bool>
+DumpTags("dump-tags", cl::desc("List all tags encountered in input"));
+
+static StringRef ToolName;
+
+/// Trivial lexer for the markup parser. Input is always handled a character
+/// at a time. The lexer just encapsulates EOF and lookahead handling.
+class MarkupLexer {
+ StringRef::const_iterator Start;
+ StringRef::const_iterator CurPtr;
+ StringRef::const_iterator End;
+public:
+ MarkupLexer(StringRef Source)
+ : Start(Source.begin()), CurPtr(Source.begin()), End(Source.end()) {}
+ // When processing non-markup, input is consumed a character at a time.
+ bool isEOF() { return CurPtr == End; }
+ int getNextChar() {
+ if (CurPtr == End) return EOF;
+ return *CurPtr++;
+ }
+ int peekNextChar() {
+ if (CurPtr == End) return EOF;
+ return *CurPtr;
+ }
+ StringRef::const_iterator getPosition() const { return CurPtr; }
+};
+
+/// A markup tag is a name and a (usually empty) list of modifiers.
+class MarkupTag {
+ StringRef Name;
+ StringRef Modifiers;
+ SMLoc StartLoc;
+public:
+ MarkupTag(StringRef n, StringRef m, SMLoc Loc)
+ : Name(n), Modifiers(m), StartLoc(Loc) {}
+ StringRef getName() const { return Name; }
+ StringRef getModifiers() const { return Modifiers; }
+ SMLoc getLoc() const { return StartLoc; }
+};
+
+/// A simple parser implementation for creating MarkupTags from input text.
+class MarkupParser {
+ MarkupLexer &Lex;
+ SourceMgr &SM;
+public:
+ MarkupParser(MarkupLexer &lex, SourceMgr &SrcMgr) : Lex(lex), SM(SrcMgr) {}
+ /// Create a MarkupTag from the current position in the MarkupLexer.
+ /// The parseTag() method should be called when the lexer has processed
+ /// the opening '<' character. Input will be consumed up to and including
+ /// the ':' which terminates the tag open.
+ MarkupTag parseTag();
+ /// Issue a diagnostic and terminate program execution.
+ void FatalError(SMLoc Loc, StringRef Msg);
+};
+
+void MarkupParser::FatalError(SMLoc Loc, StringRef Msg) {
+ SM.PrintMessage(Loc, SourceMgr::DK_Error, Msg);
+ exit(1);
+}
+
+// Example handler for when a tag is recognized.
+static void processStartTag(MarkupTag &Tag) {
+ // If we're just printing the tags, do that, otherwise do some simple
+ // colorization.
+ if (DumpTags) {
+ outs() << Tag.getName();
+ if (Tag.getModifiers().size())
+ outs() << " " << Tag.getModifiers();
+ outs() << "\n";
+ return;
+ }
+
+ if (!outs().has_colors())
+ return;
+ // Color registers as red and immediates as cyan. Those don't have nested
+ // tags, so don't bother keeping a stack of colors to reset to.
+ if (Tag.getName() == "reg")
+ outs().changeColor(raw_ostream::RED);
+ else if (Tag.getName() == "imm")
+ outs().changeColor(raw_ostream::CYAN);
+}
+
+// Example handler for when the end of a tag is recognized.
+static void processEndTag(MarkupTag &Tag) {
+ // If we're printing the tags, there's nothing more to do here. Otherwise,
+ // set the color back the normal.
+ if (DumpTags)
+ return;
+ if (!outs().has_colors())
+ return;
+ // Just reset to basic white.
+ outs().changeColor(raw_ostream::WHITE, false);
+}
+
+MarkupTag MarkupParser::parseTag() {
+ // First off, extract the tag into it's own StringRef so we can look at it
+ // outside of the context of consuming input.
+ StringRef::const_iterator Start = Lex.getPosition();
+ SMLoc Loc = SMLoc::getFromPointer(Start - 1);
+ while(Lex.getNextChar() != ':') {
+ // EOF is an error.
+ if (Lex.isEOF())
+ FatalError(SMLoc::getFromPointer(Start), "unterminated markup tag");
+ }
+ StringRef RawTag(Start, Lex.getPosition() - Start - 1);
+ std::pair<StringRef, StringRef> SplitTag = RawTag.split(' ');
+ return MarkupTag(SplitTag.first, SplitTag.second, Loc);
+}
+
+static void parseMCMarkup(StringRef Filename) {
+ OwningPtr<MemoryBuffer> BufferPtr;
+ if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, BufferPtr)) {
+ errs() << ToolName << ": " << ec.message() << '\n';
+ return;
+ }
+ MemoryBuffer *Buffer = BufferPtr.take();
+
+ SourceMgr SrcMgr;
+
+ // Tell SrcMgr about this buffer, which is what the parser will pick up.
+ SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
+
+ StringRef InputSource = Buffer->getBuffer();
+ MarkupLexer Lex(InputSource);
+ MarkupParser Parser(Lex, SrcMgr);
+
+ SmallVector<MarkupTag, 4> TagStack;
+
+ for (int CurChar = Lex.getNextChar();
+ CurChar != EOF;
+ CurChar = Lex.getNextChar()) {
+ switch (CurChar) {
+ case '<': {
+ // A "<<" is output as a literal '<' and does not start a markup tag.
+ if (Lex.peekNextChar() == '<') {
+ (void)Lex.getNextChar();
+ break;
+ }
+ // Parse the markup entry.
+ TagStack.push_back(Parser.parseTag());
+
+ // Do any special handling for the start of a tag.
+ processStartTag(TagStack.back());
+ continue;
+ }
+ case '>': {
+ SMLoc Loc = SMLoc::getFromPointer(Lex.getPosition() - 1);
+ // A ">>" is output as a literal '>' and does not end a markup tag.
+ if (Lex.peekNextChar() == '>') {
+ (void)Lex.getNextChar();
+ break;
+ }
+ // Close out the innermost tag.
+ if (TagStack.empty())
+ Parser.FatalError(Loc, "'>' without matching '<'");
+
+ // Do any special handling for the end of a tag.
+ processEndTag(TagStack.back());
+
+ TagStack.pop_back();
+ continue;
+ }
+ default:
+ break;
+ }
+ // For anything else, just echo the character back out.
+ if (!DumpTags && CurChar != EOF)
+ outs() << (char)CurChar;
+ }
+
+ // If there are any unterminated markup tags, issue diagnostics for them.
+ while (!TagStack.empty()) {
+ MarkupTag &Tag = TagStack.back();
+ SrcMgr.PrintMessage(Tag.getLoc(), SourceMgr::DK_Error,
+ "unterminated markup tag");
+ TagStack.pop_back();
+ }
+}
+
+int main(int argc, char **argv) {
+ // Print a stack trace if we signal out.
+ sys::PrintStackTraceOnErrorSignal();
+ PrettyStackTraceProgram X(argc, argv);
+
+ llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
+ cl::ParseCommandLineOptions(argc, argv, "llvm MC markup parser\n");
+
+ ToolName = argv[0];
+
+ // If no input files specified, read from stdin.
+ if (InputFilenames.size() == 0)
+ InputFilenames.push_back("-");
+
+ std::for_each(InputFilenames.begin(), InputFilenames.end(),
+ parseMCMarkup);
+ return 0;
+}
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