[llvm-rc] Add .rc scripts parser.

[mnbvmar]

Summary

This adds the parsing ability to the llvm-rc tool. Currently, it can parse a limited amount of RC statements/resources, but the other ones can be easily added to the tool.

Note that this revision is build on top of D35957.

[mnbvmar]

Style fixes.

[zturner]

llvm/test/tools/llvm-rc/Inputs/parser1.rc

1 ↗

(On Diff #109828)

Can you choose some more descriptive file names for the rc files? Maybe a short 1-3 word filename that briefly explains what's interesting about this input file. For example, test-parse-error.rc or test-everything.rc or test-stringtable.rc, etc.

llvm/tools/llvm-rc/ResourceScriptParser.h

68

node is a strange name for a namespace. Is this used anywhere else? What about rc?

77

Should these be passed by reference?

102

I think this can just be passed by value. I don't think there's anything to be gained by moving StringRefs since they're trivially copyable.

105

Might as well just use a bool here?

128

Same here, I think this can be passed by const& and just assigned.

129–132

The semicolons aren't necessary after the function body.

152–153

I think the heavy use of templates and metaprogramming here is making it hard to understand the code, while not really adding much benefit. The rc language is probably not going to be extended much in the future, so we don't have to worry about being generic to adapt to future extensions, and there also are not very many statement types to handle. I feel like it would be much easier to understand the code if there less magic hidden behind the various template classes.

Maybe someone else will weigh in though.

166

Making an rvalue reference on the stack seems a little unusual. Is this correct?

297–301

I don't really follow this comment. Can't we use the stuff in llvm/Casting.h to maintain dynamic polymorphism?

llvm/tools/llvm-rc/ResourceScriptStmt.h

100

Why do these need to be rvalue references? Passing by value seems to be more appropriate.

115–116

Same here. Do we need rvalue references here? You could probably just accept ArrayRef<BasePtr> or ArrayRef<StringTableStmt>

[mnbvmar]

llvm/tools/llvm-rc/ResourceScriptParser.h

152–153

The metaprogramming here was meant to make it easier to encode the language grammar - in case I do something in a wrong way, it should probably result in a compilation failure, not in a weird parsing error.

However, if the others also say this is really unnecessary, I'll be able rewrite the code.

297–301

Sorry for not noticing you. I locally rewrote Either as I found it counter-intuitive, too. However, new patch was not ready yet and I didn't submit it here.

[rnk]

llvm/tools/llvm-rc/ResourceScriptParser.h

152–153

I'd prefer it if this were a normal, single parser class, recursive descent parser. I'm pretty sure the resource language is LL(1), so we can pretty much look at each token in sequence, switch on it, and decide how to proceed.

166

It's the universal reference pattern, it binds to anything without making copies.

297–301

+1, the usual thing of switching on the token kind and contents is probably more readable than TMP that tries to parse template arguments in sequence.

[mnbvmar]

llvm/tools/llvm-rc/ResourceScriptParser.h

152–153

I think it's actually LL(2) as resource declarations usually follow the "[resource name] [resource type] [arguments]" convention, e.g. "1 ICON ...". (Of course, some resources don't have their names and then its type is the first token to be read.)

However, it doesn't hurt us very much and a single-class implementation is possible.

[mnbvmar]

Code rewritten a little bit.

Now, functions return objects instead of pointers to them. This will make the code more readable.

Either now takes also a base result class T and returns unique_ptr<T> (possibly upcasted from the created object). This way, we get dynamic polymorphism "for free."

[mnbvmar]

Parser rewritten to a single non-templated class. The new patch supports the same set of resources as before.

[mnbvmar]

Some comments stopped being relevant to the current patch.

[ecbeckmann]

llvm/tools/llvm-rc/ResourceScriptParser.cpp

72

nit: Name could be clearer, such as "doesNextTokenMatchKind()" or "isNextTokenKind()".

[kuhar]

llvm/tools/llvm-rc/ResourceScriptStmt.h

38

nit: Is there a point moving StringRefs here? I think that internally StringRef is something like a pointer and length.

[mnbvmar]

Small style fixes according to the suggestions.

[mnbvmar]

llvm/tools/llvm-rc/ResourceScriptParser.cpp

44

The pattern above:

auto Something = tryGetSomething(); // returns Expected<T>
if (!Something)
  return Something.takeError();
// Now we can use *Something to get the value of type T.

occurs in many parts of the parser. Maybe it is better to replace this pattern with a macro creating variable Something or fails, that is:

#define ASSIGN_OR_RETURN(var, expr)                                            \
  auto var = (expr);                                                           \
  if (!var)                                                                    \
    return var.takeError();

// ...
ASSIGN_OR_RETURN(Something, tryGetSomething());
// Now, use *Something.

Do you think it'd be more readable?

[zturner]

This looks MUCH better. Thanks

llvm/tools/llvm-rc/ResourceScriptParser.cpp

189–200

Do we need this to be a lambda? It will construct one of these on the stack every iteration of the loop. It seems like it should just be a global static function

llvm/tools/llvm-rc/ResourceScriptParser.h

88

Why is it returning an empty tuple? What's the point of the return value if it contains no information?

llvm/tools/llvm-rc/ResourceScriptStmt.h

74

I think it can just take this argument by value.

[ecbeckmann]

llvm/tools/llvm-rc/ResourceScriptParser.cpp

44

I think a macro is valid here, I've done it in other parts of the codebase, see RETURN_IF_ERROR in COFFObjectFile.cpp

[mnbvmar]

llvm/tools/llvm-rc/ResourceScriptParser.h

88

It returns nothing or an error message. Error might be better here.

[mnbvmar]

Style fixes, added macro-based error handling.

[zturner]

lgtm

[mnbvmar]

Tests failed locally on Windows; fixed their invocation.

llvm/test/tools/llvm-rc/Inputs/parser-correct-everything.rc

+meh IcOn "hello.bmp"
+Icon Icon "Icon"
+
+LANGUAGE 5, 12
+
+STRINGTABLE
+LANGUAGE 1, 1
+CHARACTERISTICS 500
+LANGUAGE 3, 4
+VERSION 14
+{
+  1 "hello"
+  2 "world"
+}
+STRINGTABLE BEGIN END

llvm/test/tools/llvm-rc/Inputs/parser-eof.rc

+LANGUAGE

llvm/test/tools/llvm-rc/Inputs/parser-language-no-comma.rc

+LANGUAGE 5 7

llvm/test/tools/llvm-rc/Inputs/parser-language-too-many-commas.rc

+LANGUAGE 5,, 7

llvm/test/tools/llvm-rc/Inputs/parser-no-characteristics-arg.rc

+STRINGTABLE
+CHARACTERISTICS
+BEGIN
+  100 "No integer after CHARACTERISTICS."
+END

llvm/test/tools/llvm-rc/Inputs/parser-nonsense-token.rc

+& ICON "WeirdResourceName.ico"

llvm/test/tools/llvm-rc/Inputs/parser-nonsense-type-eof.rc

+HELLO

llvm/test/tools/llvm-rc/Inputs/parser-nonsense-type.rc

+HELLO WORLD

llvm/test/tools/llvm-rc/Inputs/parser-stringtable-no-string.rc

+STRINGTABLE
+VERSION 8
+{
+  1 "hello"
+  2
+}

llvm/test/tools/llvm-rc/Inputs/parser-stringtable-weird-option.rc

+STRINGTABLE
+NONSENSETYPE 12 34
+BEGIN
+END

llvm/test/tools/llvm-rc/parser.test

+; RUN: llvm-rc /V %p/Inputs/parser-correct-everything.rc | FileCheck %s --check-prefix PGOOD
+
+; PGOOD:  Icon (meh): "hello.bmp"
+; PGOOD-NEXT:  Icon (Icon): "Icon"
+; PGOOD-NEXT:  Language: 5, Sublanguage: 12
+; PGOOD-NEXT:  StringTable:
+; PGOOD-NEXT:    Option: Language: 1, Sublanguage: 1
+; PGOOD-NEXT:    Option: Characteristics: 500
+; PGOOD-NEXT:    Option: Language: 3, Sublanguage: 4
+; PGOOD-NEXT:    Option: Version: 14
+; PGOOD-NEXT:    1 => "hello"
+; PGOOD-NEXT:    2 => "world"
+; PGOOD-NEXT:  StringTable:
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-stringtable-no-string.rc 2> %t2 || true
+; RUN: FileCheck %s --check-prefix PSTRINGTABLE1 --input-file %t2
+
+; PSTRINGTABLE1:  llvm-rc: Error parsing file: expected string, got }
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-stringtable-weird-option.rc 2> %t3 || true
+; RUN: FileCheck %s --check-prefix PSTRINGTABLE2 --input-file %t3
+
+; PSTRINGTABLE2:  llvm-rc: Error parsing file: expected optional statement type, BEGIN or '{', got NONSENSETYPE
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-eof.rc 2> %t4 || true
+; RUN: FileCheck %s --check-prefix PEOF --input-file %t4
+
+; PEOF:  llvm-rc: Error parsing file: expected integer, got <EOF>
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-no-characteristics-arg.rc 2> %t5 || true
+; RUN: FileCheck %s --check-prefix PCHARACTERISTICS1 --input-file %t5
+
+; PCHARACTERISTICS1:  llvm-rc: Error parsing file: expected integer, got BEGIN
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-nonsense-token.rc 2> %t6 || true
+; RUN: FileCheck %s --check-prefix PNONSENSE1 --input-file %t6
+
+; PNONSENSE1:  llvm-rc: Error parsing file: expected int or identifier, got &
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-nonsense-type.rc 2> %t7 || true
+; RUN: FileCheck %s --check-prefix PNONSENSE2 --input-file %t7
+
+; PNONSENSE2:  llvm-rc: Error parsing file: expected resource type, got WORLD
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-nonsense-type-eof.rc 2> %t8 || true
+; RUN: FileCheck %s --check-prefix PNONSENSE3 --input-file %t8
+
+; PNONSENSE3:  llvm-rc: Error parsing file: expected int or identifier, got <EOF>
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-language-no-comma.rc 2> %t9 || true
+; RUN: FileCheck %s --check-prefix PLANGUAGE1 --input-file %t9
+
+; PLANGUAGE1:  llvm-rc: Error parsing file: expected ',', got 7
+
+
+; RUN: llvm-rc /V %p/Inputs/parser-language-too-many-commas.rc 2> %t10 || true
+; RUN: FileCheck %s --check-prefix PLANGUAGE2 --input-file %t10
+
+; PLANGUAGE2:  llvm-rc: Error parsing file: expected integer, got ,

llvm/test/tools/llvm-rc/tokenizer.test

-; RUN: llvm-rc /V %p/Inputs/tokens.rc | FileCheck %s
+; RUN: (llvm-rc /V %p/Inputs/tokens.rc || true) | FileCheck %s
+; llvm-rc fails now on this sample because it is an invalid resource file
+; script. We silence the error message and just analyze the output.
 
 ; CHECK:  Int: 1; int value = 1
 ; CHECK-NEXT:  Plus: +
 ; CHECK-NEXT:  Int: 2; int value = 2
 ; CHECK-NEXT:  Minus: -
 ; CHECK-NEXT:  Int: 3214L; int value = 3214
 ; CHECK-NEXT:  Amp: &
 ; CHECK-NEXT:  Int: 0x120894; int value = 1181844

llvm/tools/llvm-rc/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Option
   Support
   )
 
 set(LLVM_TARGET_DEFINITIONS Opts.td)
 
 tablegen(LLVM Opts.inc -gen-opt-parser-defs)
 add_public_tablegen_target(RcTableGen)
 
 add_llvm_tool(llvm-rc
   llvm-rc.cpp
+  ResourceScriptParser.cpp
+  ResourceScriptStmt.cpp
   ResourceScriptToken.cpp
   )

llvm/tools/llvm-rc/ResourceScriptParser.h

+//===-- ResourceScriptParser.h ----------------------------------*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+//
+// This defines the RC scripts parser. It takes a sequence of RC tokens
+// and then provides the method to parse the resources one by one.
+//
+//===---------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVMRC_RESOURCESCRIPTPARSER_H
+#define LLVM_TOOLS_LLVMRC_RESOURCESCRIPTPARSER_H
+
+#include "ResourceScriptStmt.h"
+#include "ResourceScriptToken.h"
+
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <system_error>
+#include <vector>
+
+namespace llvm {
+namespace rc {
+
+class RCParser {
+public:
+  using LocIter = std::vector<RCToken>::iterator;
+  using ParseType = Expected<std::unique_ptr<RCResource>>;
+  using ParseOptionType = Expected<std::unique_ptr<OptionalStmt>>;
+
+  // Class describing a single failure of parser.
+  class ParserError : public ErrorInfo<ParserError> {
+  public:
+    ParserError(Twine Expected, const LocIter CurLoc, const LocIter End);
+
+    void log(raw_ostream &OS) const override { OS << CurMessage; }
+    std::error_code convertToErrorCode() const override {
+      return std::make_error_code(std::errc::invalid_argument);
+    }
+    const std::string &getMessage() const { return CurMessage; }
+
+    static char ID; // Keep llvm::Error happy.
+
+  private:
+    std::string CurMessage;
+    LocIter ErrorLoc, FileEnd;
+  };
+
+  RCParser(const std::vector<RCToken> &TokenList);
+  RCParser(std::vector<RCToken> &&TokenList);
+
+  // Reads and returns a single resource definition, or error message if any
+  // occurred.
+  ParseType parseSingleResource();
+
+  bool isEof() const;
+
+private:
+  using Kind = RCToken::Kind;
+
+  // Checks if the current parser state points to the token of type TokenKind.
+  bool isNextTokenKind(Kind TokenKind) const;
+
+  // These methods assume that the parser is not in EOF state.
+
+  // Take a look at the current token. Do not fetch it.
+  const RCToken &look() const;
+  // Read the current token and advance the state by one token.
+  const RCToken &read();
+  // Advance the state by one token, discarding the current token.
+  void consume();
+
+  // The following methods try to read a single token, check if it has the
+  // correct type and then parse it.
+  Expected<uint32_t> readInt();           // Parse an integer.
+  Expected<StringRef> readString();       // Parse a string.
+  Expected<StringRef> readIdentifier();   // Parse an identifier.
+  Expected<IntOrString> readTypeOrName(); // Parse an integer or an identifier.
+
+  // Advance the state by one, discarding the current token.
+  // If the discarded token had an incorrect type, fail.
+  Error consumeType(Kind TokenKind);
+
+  // Check the current token type. If it's TokenKind, discard it.
+  // Return true if the parser consumed this token successfully.
+  bool consumeOptionalType(Kind TokenKind);
+
+  // Read at least MinCount, and at most MaxCount integers separated by
+  // commas. The parser stops reading after fetching MaxCount integers
+  // or after an error occurs. Whenever the parser reads a comma, it
+  // expects an integer to follow.
+  Expected<SmallVector<uint32_t, 8>> readIntsWithCommas(size_t MinCount,
+                                                        size_t MaxCount);
+
+  // Reads a set of optional statements. These can change the behavior of
+  // a number of resource types (e.g. STRINGTABLE, MENU or DIALOG) if provided
+  // before the main block with the contents of the resource.
+  // Usually, resources use a basic set of optional statements:
+  //    CHARACTERISTICS, LANGUAGE, VERSION
+  // However, DIALOG and DIALOGEX extend this list by the following items:
+  //    CAPTION, CLASS, EXSTYLE, FONT, MENU, STYLE
+  // UseExtendedStatements flag (off by default) allows the parser to read
+  // the additional types of statements.
+  //
+  // Ref (to the list of all optional statements):
+  //    msdn.microsoft.com/en-us/library/windows/desktop/aa381002(v=vs.85).aspx
+  Expected<OptionalStmtList>
+  parseOptionalStatements(bool UseExtendedStatements = false);
+
+  // Read a single optional statement.
+  Expected<std::unique_ptr<OptionalStmt>>
+  parseSingleOptionalStatement(bool UseExtendedStatements = false);
+
+  // Top-level resource parsers.
+  ParseType parseLanguageResource();
+  ParseType parseIconResource();
+  ParseType parseStringTableResource();
+
+  // Optional statement parsers.
+  ParseOptionType parseLanguageStmt();
+  ParseOptionType parseCharacteristicsStmt();
+  ParseOptionType parseVersionStmt();
+
+  // Raises an error. If IsAlreadyRead = false (default), this complains about
+  // the token that couldn't be parsed. If the flag is on, this complains about
+  // the correctly read token that makes no sense (that is, the current parser
+  // state is beyond the erroneous token.)
+  Error getExpectedError(const Twine Message, bool IsAlreadyRead = false);
+
+  std::vector<RCToken> Tokens;
+  LocIter CurLoc;
+  const LocIter End;
+};
+
+} // namespace rc
+} // namespace llvm
+
+#endif

llvm/tools/llvm-rc/ResourceScriptParser.cpp

+//===-- ResourceScriptParser.cpp --------------------------------*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+//
+// This implements the parser defined in ResourceScriptParser.h.
+//
+//===---------------------------------------------------------------------===//
+
+#include "ResourceScriptParser.h"
+
+// Take an expression returning llvm::Error and forward the error if it exists.
+#define RETURN_IF_ERROR(Expr)                                                  \
+  if (auto Err = (Expr))                                                       \
+    return std::move(Err);
+
+// Take an expression returning llvm::Expected<T> and assign it to Var or
+// forward the error out of the function.
+#define ASSIGN_OR_RETURN(Var, Expr)                                            \
+  auto Var = (Expr);                                                           \
+  if (!Var)                                                                    \
+    return Var.takeError();
+
+namespace llvm {
+namespace rc {
+
+RCParser::ParserError::ParserError(const Twine Expected, const LocIter CurLoc,
+                                   const LocIter End)
+    : ErrorLoc(CurLoc), FileEnd(End) {
+  CurMessage = "Error parsing file: expected " + Expected.str() + ", got " +
+               (CurLoc == End ? "<EOF>" : CurLoc->value()).str();
+}
+
+char RCParser::ParserError::ID = 0;
+
+RCParser::RCParser(const std::vector<RCToken> &TokenList)
+    : Tokens(TokenList), CurLoc(Tokens.begin()), End(Tokens.end()) {}
+
+RCParser::RCParser(std::vector<RCToken> &&TokenList)
+    : Tokens(std::move(TokenList)), CurLoc(Tokens.begin()), End(Tokens.end()) {}
+
+bool RCParser::isEof() const { return CurLoc == End; }
+
+RCParser::ParseType RCParser::parseSingleResource() {
+  // The first thing we read is usually a resource's name. However, in some
+  // cases (LANGUAGE and STRINGTABLE) the resources don't have their names
+  // and the first token to be read is the type.
+  ASSIGN_OR_RETURN(NameToken, readTypeOrName());
+
+  if (NameToken->equalsLower("LANGUAGE"))
+    return parseLanguageResource();
+  else if (NameToken->equalsLower("STRINGTABLE"))
+    return parseStringTableResource();
+
+  // If it's not an unnamed resource, what we've just read is a name. Now,
+  // read resource type;
+  ASSIGN_OR_RETURN(TypeToken, readTypeOrName());
+
+  ParseType Result = std::unique_ptr<RCResource>();
+  (void)!Result;
+
+  if (TypeToken->equalsLower("ICON"))
+    Result = parseIconResource();
+  else
+    return getExpectedError("resource type", /* IsAlreadyRead = */ true);
+
+  if (Result)
+    (*Result)->setName(*NameToken);
+
+  return Result;
+}
+
+bool RCParser::isNextTokenKind(Kind TokenKind) const {
+  return !isEof() && look().kind() == TokenKind;
+}
+
+const RCToken &RCParser::look() const {
+  assert(!isEof());
+  return *CurLoc;
+}
+
+const RCToken &RCParser::read() {
+  assert(!isEof());
+  return *CurLoc++;
+}
+
+void RCParser::consume() {
+  assert(!isEof());
+  CurLoc++;
+}
+
+Expected<uint32_t> RCParser::readInt() {
+  if (!isNextTokenKind(Kind::Int))
+    return getExpectedError("integer");
+  return read().intValue();
+}
+
+Expected<StringRef> RCParser::readString() {
+  if (!isNextTokenKind(Kind::String))
+    return getExpectedError("string");
+  return read().value();
+}
+
+Expected<StringRef> RCParser::readIdentifier() {
+  if (!isNextTokenKind(Kind::Identifier))
+    return getExpectedError("identifier");
+  return read().value();
+}
+
+Expected<IntOrString> RCParser::readTypeOrName() {
+  // We suggest that the correct resource name or type should be either an
+  // identifier or an integer. The original RC tool is much more liberal.
+  if (!isNextTokenKind(Kind::Identifier) && !isNextTokenKind(Kind::Int))
+    return getExpectedError("int or identifier");
+
+  const RCToken &Tok = read();
+  if (Tok.kind() == Kind::Int)
+    return IntOrString(Tok.intValue());
+  else
+    return IntOrString(Tok.value());
+}
+
+Error RCParser::consumeType(Kind TokenKind) {
+  if (isNextTokenKind(TokenKind)) {
+    consume();
+    return Error::success();
+  }
+
+  switch (TokenKind) {
+#define TOKEN(TokenName)                                                       \
+  case Kind::TokenName:                                                        \
+    return getExpectedError(#TokenName);
+#define SHORT_TOKEN(TokenName, TokenCh)                                        \
+  case Kind::TokenName:                                                        \
+    return getExpectedError(#TokenCh);
+#include "ResourceScriptTokenList.h"
+#undef SHORT_TOKEN
+#undef TOKEN
+  }
+}
+
+bool RCParser::consumeOptionalType(Kind TokenKind) {
+  if (isNextTokenKind(TokenKind)) {
+    consume();
+    return true;
+  }
+
+  return false;
+}
+
+Expected<SmallVector<uint32_t, 8>>
+RCParser::readIntsWithCommas(size_t MinCount, size_t MaxCount) {
+  assert(MinCount <= MaxCount);
+
+  SmallVector<uint32_t, 8> Result;
+
+  auto FailureHandler =
+      [&](llvm::Error Err) -> Expected<SmallVector<uint32_t, 8>> {
+    if (Result.size() < MinCount)
+      return std::move(Err);
+    consumeError(std::move(Err));
+    return Result;
+  };
+
+  for (size_t i = 0; i < MaxCount; ++i) {
+    // Try to read a comma unless we read the first token.
+    // Sometimes RC tool requires them and sometimes not. We decide to
+    // always require them.
+    if (i >= 1) {
+      if (auto CommaError = consumeType(Kind::Comma))
+        return FailureHandler(std::move(CommaError));
+    }
+
+    if (auto IntResult = readInt())
+      Result.push_back(*IntResult);
+    else
+      return FailureHandler(IntResult.takeError());
+  }
+
+  return Result;
+}
+
+// As for now, we ignore the extended set of statements.
+Expected<OptionalStmtList> RCParser::parseOptionalStatements(bool IsExtended) {
+  OptionalStmtList Result;
+
+  // The last statement is always followed by the start of the block.
+  while (!isNextTokenKind(Kind::BlockBegin)) {
+    ASSIGN_OR_RETURN(SingleParse, parseSingleOptionalStatement(IsExtended));
+    Result.addStmt(std::move(*SingleParse));
+  }
+
+  return Result;
+}
+
+Expected<std::unique_ptr<OptionalStmt>>
+RCParser::parseSingleOptionalStatement(bool) {
+  ASSIGN_OR_RETURN(TypeToken, readIdentifier());
+  if (TypeToken->equals_lower("CHARACTERISTICS"))
+    return parseCharacteristicsStmt();
+  else if (TypeToken->equals_lower("LANGUAGE"))
+    return parseLanguageStmt();
+  else if (TypeToken->equals_lower("VERSION"))
+    return parseVersionStmt();
+  else
+    return getExpectedError("optional statement type, BEGIN or '{'",
+                            /* IsAlreadyRead = */ true);
+}
+
+RCParser::ParseType RCParser::parseLanguageResource() {
+  // Read LANGUAGE as an optional statement. If it's read correctly, we can
+  // upcast it to RCResource.
+  return parseLanguageStmt();
+}
+
+RCParser::ParseType RCParser::parseIconResource() {
+  ASSIGN_OR_RETURN(Arg, readString());
+  return make_unique<IconResource>(*Arg);
+}
+
+RCParser::ParseType RCParser::parseStringTableResource() {
+  ASSIGN_OR_RETURN(OptStatements, parseOptionalStatements());
+  RETURN_IF_ERROR(consumeType(Kind::BlockBegin));
+
+  auto Table = make_unique<StringTableResource>(std::move(*OptStatements));
+
+  // Read strings until we reach the end of the block.
+  while (!consumeOptionalType(Kind::BlockEnd)) {
+    // Each definition consists of string's ID (an integer) and a string.
+    // Some examples in documentation suggest that there might be a comma in
+    // between, however we strictly adhere to the single statement definition.
+    ASSIGN_OR_RETURN(IDResult, readInt());
+    ASSIGN_OR_RETURN(StrResult, readString());
+    Table->addString(*IDResult, *StrResult);
+  }
+
+  return Table;
+}
+
+RCParser::ParseOptionType RCParser::parseLanguageStmt() {
+  ASSIGN_OR_RETURN(Args, readIntsWithCommas(/* min = */ 2, /* max = */ 2));
+  return make_unique<LanguageResource>((*Args)[0], (*Args)[1]);
+}
+
+RCParser::ParseOptionType RCParser::parseCharacteristicsStmt() {
+  ASSIGN_OR_RETURN(Arg, readInt());
+  return make_unique<CharacteristicsStmt>(*Arg);
+}
+
+RCParser::ParseOptionType RCParser::parseVersionStmt() {
+  ASSIGN_OR_RETURN(Arg, readInt());
+  return make_unique<VersionStmt>(*Arg);
+}
+
+Error RCParser::getExpectedError(const Twine Message, bool IsAlreadyRead) {
+  return make_error<ParserError>(
+      Message, IsAlreadyRead ? std::prev(CurLoc) : CurLoc, End);
+}
+
+} // namespace rc
+} // namespace llvm

llvm/tools/llvm-rc/ResourceScriptStmt.h

+//===-- ResourceScriptStmt.h ------------------------------------*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+//
+// This lists all the resource and statement types occurring in RC scripts.
+//
+//===---------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVMRC_RESOURCESCRIPTSTMT_H
+#define LLVM_TOOLS_LLVMRC_RESOURCESCRIPTSTMT_H
+
+#include "ResourceScriptToken.h"
+
+namespace llvm {
+namespace rc {
+
+// A class holding a name - either an integer or a reference to the string.
+class IntOrString {
+private:
+  union Data {
+    uint32_t Int;
+    StringRef String;
+    Data(uint32_t Value) : Int(Value) {}
+    Data(const StringRef Value) : String(Value) {}
+    Data(const RCToken &Token);
+  } Data;
+  bool IsInt;
+
+public:
+  IntOrString() : IntOrString(0) {}
+  IntOrString(uint32_t Value) : Data(Value), IsInt(1) {}
+  IntOrString(StringRef Value) : Data(Value), IsInt(0) {}
+  IntOrString(const RCToken &Token)
+      : Data(Token), IsInt(Token.kind() == RCToken::Kind::Int) {}
+
+  bool equalsLower(const char *Str) {
+    return !IsInt && Data.String.equals_lower(Str);
+  }
+
+  friend raw_ostream &operator<<(raw_ostream &, const IntOrString &);
+};
+
+// Base resource. All the resources should derive from this base.
+class RCResource {
+protected:
+  IntOrString ResName;
+
+public:
+  RCResource() = default;
+  RCResource(RCResource &&) = default;
+  void setName(const IntOrString &Name) { ResName = Name; }
+  virtual raw_ostream &log(raw_ostream &OS) const {
+    return OS << "Base statement\n";
+  };
+  virtual ~RCResource() {}
+};
+
+// Optional statement base. All such statements should derive from this base.
+class OptionalStmt : public RCResource {};
+
+class OptionalStmtList : public OptionalStmt {
+  std::vector<std::unique_ptr<OptionalStmt>> Statements;
+
+public:
+  OptionalStmtList() {}
+  virtual raw_ostream &log(raw_ostream &OS) const;
+
+  void addStmt(std::unique_ptr<OptionalStmt> Stmt) {
+    Statements.push_back(std::move(Stmt));
+  }
+};
+
+// LANGUAGE statement. It can occur both as a top-level statement (in such
+// a situation, it changes the default language until the end of the file)
+// and as an optional resource statement (then it changes the language
+// of a single resource).
+//
+// Ref: msdn.microsoft.com/en-us/library/windows/desktop/aa381019(v=vs.85).aspx
+class LanguageResource : public OptionalStmt {
+  uint32_t Lang, SubLang;
+
+public:
+  LanguageResource(uint32_t LangId, uint32_t SubLangId)
+      : Lang(LangId), SubLang(SubLangId) {}
+  raw_ostream &log(raw_ostream &) const override;
+};
+
+// ICON resource. Represents a single ".ico" file containing a group of icons.
+//
+// Ref: msdn.microsoft.com/en-us/library/windows/desktop/aa381018(v=vs.85).aspx
+class IconResource : public RCResource {
+  StringRef IconLoc;
+
+public:
+  IconResource(StringRef Location) : IconLoc(Location) {}
+  raw_ostream &log(raw_ostream &) const override;
+};
+
+// STRINGTABLE resource. Contains a list of strings, each having its unique ID.
+//
+// Ref: msdn.microsoft.com/en-us/library/windows/desktop/aa381050(v=vs.85).aspx
+class StringTableResource : public RCResource {
+  OptionalStmtList OptStatements;
+  std::vector<std::pair<uint32_t, StringRef>> Table;
+
+public:
+  StringTableResource(OptionalStmtList &&OptStmts)
+      : OptStatements(std::move(OptStmts)) {}
+  void addString(uint32_t ID, StringRef String) {
+    Table.emplace_back(ID, String);
+  }
+  raw_ostream &log(raw_ostream &) const override;
+};
+
+// CHARACTERISTICS optional statement.
+//
+// Ref: msdn.microsoft.com/en-us/library/windows/desktop/aa380872(v=vs.85).aspx
+class CharacteristicsStmt : public OptionalStmt {
+  uint32_t Value;
+
+public:
+  CharacteristicsStmt(uint32_t Characteristic) : Value(Characteristic) {}
+  raw_ostream &log(raw_ostream &) const override;
+};
+
+// VERSION optional statement.
+//
+// Ref: msdn.microsoft.com/en-us/library/windows/desktop/aa381059(v=vs.85).aspx
+class VersionStmt : public OptionalStmt {
+  uint32_t Value;
+
+public:
+  VersionStmt(uint32_t Version) : Value(Version) {}
+  raw_ostream &log(raw_ostream &) const override;
+};
+
+} // namespace rc
+} // namespace llvm
+
+#endif

llvm/tools/llvm-rc/ResourceScriptStmt.cpp

+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+//
+// This implements methods defined in ResourceScriptStmt.h.
+//
+// Ref: msdn.microsoft.com/en-us/library/windows/desktop/aa380599(v=vs.85).aspx
+//
+//===---------------------------------------------------------------------===//
+
+#include "ResourceScriptStmt.h"
+
+namespace llvm {
+namespace rc {
+
+raw_ostream &operator<<(raw_ostream &OS, const IntOrString &Item) {
+  if (Item.IsInt)
+    return OS << Item.Data.Int;
+  else
+    return OS << Item.Data.String;
+}
+
+raw_ostream &OptionalStmtList::log(raw_ostream &OS) const {
+  for (const auto &Stmt : Statements) {
+    OS << "  Option: ";
+    Stmt->log(OS);
+  }
+  return OS;
+}
+
+raw_ostream &LanguageResource::log(raw_ostream &OS) const {
+  return OS << "Language: " << Lang << ", Sublanguage: " << SubLang << "\n";
+}
+
+raw_ostream &IconResource::log(raw_ostream &OS) const {
+  return OS << "Icon (" << ResName << "): " << IconLoc << "\n";
+}
+
+raw_ostream &StringTableResource::log(raw_ostream &OS) const {
+  OS << "StringTable:\n";
+  OptStatements.log(OS);
+  for (const auto &String : Table)
+    OS << "  " << String.first << " => " << String.second << "\n";
+  return OS;
+}
+
+raw_ostream &CharacteristicsStmt::log(raw_ostream &OS) const {
+  return OS << "Characteristics: " << Value << "\n";
+}
+
+raw_ostream &VersionStmt::log(raw_ostream &OS) const {
+  return OS << "Version: " << Value << "\n";
+}
+
+} // namespace rc
+} // namespace llvm

llvm/tools/llvm-rc/llvm-rc.cpp

 //===-- llvm-rc.cpp - Compile .rc scripts into .res -------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Compile .rc scripts into .res files. This is intended to be a
 // platform-independent port of Microsoft's rc.exe tool.
 //
 //===----------------------------------------------------------------------===//
 
 #include "ResourceScriptToken.h"
+#include "ResourceScriptParser.h"
 
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Signals.h"
for (const RCToken &Token : Tokens) {
              << Token.value();
       if (Token.kind() == RCToken::Kind::Int)
         outs() << "; int value = " << Token.intValue();
 
       outs() << "\n";
     }
   }
 
+  rc::RCParser Parser{std::move(Tokens)};
+  while (!Parser.isEof()) {
+    auto Resource = ExitOnErr(Parser.parseSingleResource());
+    if (BeVerbose)
+      Resource->log(outs());
+  }
+
   return 0;
 }