1 files changed, 272 insertions, 0 deletions
diff --git a/clang/lib/Lex/TokenConcatenation.cpp b/clang/lib/Lex/TokenConcatenation.cpp
new file mode 100644
index 0000000..84a46ed
--- /dev/null
+++ b/clang/lib/Lex/TokenConcatenation.cpp
@@ -0,0 +1,272 @@
+//===--- TokenConcatenation.cpp - Token Concatenation Avoidance -----------===//
+//
+//                     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 TokenConcatenation class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Lex/TokenConcatenation.h"
+#include "clang/Lex/Preprocessor.h"
+#include "llvm/Support/ErrorHandling.h"
+using namespace clang;
+
+
+/// IsStringPrefix - Return true if Str is a string prefix.
+/// 'L', 'u', 'U', or 'u8'. Including raw versions.
+static bool IsStringPrefix(StringRef Str, bool CPlusPlus0x) {
+
+  if (Str[0] == 'L' ||
+      (CPlusPlus0x && (Str[0] == 'u' || Str[0] == 'U' || Str[0] == 'R'))) {
+
+    if (Str.size() == 1)
+      return true; // "L", "u", "U", and "R"
+
+    // Check for raw flavors. Need to make sure the first character wasn't
+    // already R. Need CPlusPlus0x check for "LR".
+    if (Str[1] == 'R' && Str[0] != 'R' && Str.size() == 2 && CPlusPlus0x)
+      return true; // "LR", "uR", "UR"
+
+    // Check for "u8" and "u8R"
+    if (Str[0] == 'u' && Str[1] == '8') {
+      if (Str.size() == 2) return true; // "u8"
+      if (Str.size() == 3 && Str[2] == 'R') return true; // "u8R"
+    }
+  }
+
+  return false;
+}
+
+/// IsIdentifierStringPrefix - Return true if the spelling of the token
+/// is literally 'L', 'u', 'U', or 'u8'. Including raw versions.
+bool TokenConcatenation::IsIdentifierStringPrefix(const Token &Tok) const {
+  const LangOptions &LangOpts = PP.getLangOpts();
+
+  if (!Tok.needsCleaning()) {
+    if (Tok.getLength() < 1 || Tok.getLength() > 3)
+      return false;
+    SourceManager &SM = PP.getSourceManager();
+    const char *Ptr = SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation()));
+    return IsStringPrefix(StringRef(Ptr, Tok.getLength()),
+                          LangOpts.CPlusPlus0x);
+  }
+
+  if (Tok.getLength() < 256) {
+    char Buffer[256];
+    const char *TokPtr = Buffer;
+    unsigned length = PP.getSpelling(Tok, TokPtr);
+    return IsStringPrefix(StringRef(TokPtr, length), LangOpts.CPlusPlus0x);
+  }
+
+  return IsStringPrefix(StringRef(PP.getSpelling(Tok)), LangOpts.CPlusPlus0x);
+}
+
+TokenConcatenation::TokenConcatenation(Preprocessor &pp) : PP(pp) {
+  memset(TokenInfo, 0, sizeof(TokenInfo));
+
+  // These tokens have custom code in AvoidConcat.
+  TokenInfo[tok::identifier      ] |= aci_custom;
+  TokenInfo[tok::numeric_constant] |= aci_custom_firstchar;
+  TokenInfo[tok::period          ] |= aci_custom_firstchar;
+  TokenInfo[tok::amp             ] |= aci_custom_firstchar;
+  TokenInfo[tok::plus            ] |= aci_custom_firstchar;
+  TokenInfo[tok::minus           ] |= aci_custom_firstchar;
+  TokenInfo[tok::slash           ] |= aci_custom_firstchar;
+  TokenInfo[tok::less            ] |= aci_custom_firstchar;
+  TokenInfo[tok::greater         ] |= aci_custom_firstchar;
+  TokenInfo[tok::pipe            ] |= aci_custom_firstchar;
+  TokenInfo[tok::percent         ] |= aci_custom_firstchar;
+  TokenInfo[tok::colon           ] |= aci_custom_firstchar;
+  TokenInfo[tok::hash            ] |= aci_custom_firstchar;
+  TokenInfo[tok::arrow           ] |= aci_custom_firstchar;
+
+  // These tokens have custom code in C++11 mode.
+  if (PP.getLangOpts().CPlusPlus0x) {
+    TokenInfo[tok::string_literal      ] |= aci_custom;
+    TokenInfo[tok::wide_string_literal ] |= aci_custom;
+    TokenInfo[tok::utf8_string_literal ] |= aci_custom;
+    TokenInfo[tok::utf16_string_literal] |= aci_custom;
+    TokenInfo[tok::utf32_string_literal] |= aci_custom;
+    TokenInfo[tok::char_constant       ] |= aci_custom;
+    TokenInfo[tok::wide_char_constant  ] |= aci_custom;
+    TokenInfo[tok::utf16_char_constant ] |= aci_custom;
+    TokenInfo[tok::utf32_char_constant ] |= aci_custom;
+  }
+
+  // These tokens change behavior if followed by an '='.
+  TokenInfo[tok::amp         ] |= aci_avoid_equal;           // &=
+  TokenInfo[tok::plus        ] |= aci_avoid_equal;           // +=
+  TokenInfo[tok::minus       ] |= aci_avoid_equal;           // -=
+  TokenInfo[tok::slash       ] |= aci_avoid_equal;           // /=
+  TokenInfo[tok::less        ] |= aci_avoid_equal;           // <=
+  TokenInfo[tok::greater     ] |= aci_avoid_equal;           // >=
+  TokenInfo[tok::pipe        ] |= aci_avoid_equal;           // |=
+  TokenInfo[tok::percent     ] |= aci_avoid_equal;           // %=
+  TokenInfo[tok::star        ] |= aci_avoid_equal;           // *=
+  TokenInfo[tok::exclaim     ] |= aci_avoid_equal;           // !=
+  TokenInfo[tok::lessless    ] |= aci_avoid_equal;           // <<=
+  TokenInfo[tok::greatergreater] |= aci_avoid_equal;         // >>=
+  TokenInfo[tok::caret       ] |= aci_avoid_equal;           // ^=
+  TokenInfo[tok::equal       ] |= aci_avoid_equal;           // ==
+}
+
+/// GetFirstChar - Get the first character of the token \arg Tok,
+/// avoiding calls to getSpelling where possible.
+static char GetFirstChar(Preprocessor &PP, const Token &Tok) {
+  if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
+    // Avoid spelling identifiers, the most common form of token.
+    return II->getNameStart()[0];
+  } else if (!Tok.needsCleaning()) {
+    if (Tok.isLiteral() && Tok.getLiteralData()) {
+      return *Tok.getLiteralData();
+    } else {
+      SourceManager &SM = PP.getSourceManager();
+      return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation()));
+    }
+  } else if (Tok.getLength() < 256) {
+    char Buffer[256];
+    const char *TokPtr = Buffer;
+    PP.getSpelling(Tok, TokPtr);
+    return TokPtr[0];
+  } else {
+    return PP.getSpelling(Tok)[0];
+  }
+}
+
+/// AvoidConcat - If printing PrevTok immediately followed by Tok would cause
+/// the two individual tokens to be lexed as a single token, return true
+/// (which causes a space to be printed between them).  This allows the output
+/// of -E mode to be lexed to the same token stream as lexing the input
+/// directly would.
+///
+/// This code must conservatively return true if it doesn't want to be 100%
+/// accurate.  This will cause the output to include extra space characters,
+/// but the resulting output won't have incorrect concatenations going on.
+/// Examples include "..", which we print with a space between, because we
+/// don't want to track enough to tell "x.." from "...".
+bool TokenConcatenation::AvoidConcat(const Token &PrevPrevTok,
+                                     const Token &PrevTok,
+                                     const Token &Tok) const {
+  // First, check to see if the tokens were directly adjacent in the original
+  // source.  If they were, it must be okay to stick them together: if there
+  // were an issue, the tokens would have been lexed differently.
+  if (PrevTok.getLocation().isFileID() && Tok.getLocation().isFileID() &&
+      PrevTok.getLocation().getLocWithOffset(PrevTok.getLength()) ==
+        Tok.getLocation())
+    return false;
+
+  tok::TokenKind PrevKind = PrevTok.getKind();
+  if (PrevTok.getIdentifierInfo())  // Language keyword or named operator.
+    PrevKind = tok::identifier;
+
+  // Look up information on when we should avoid concatenation with prevtok.
+  unsigned ConcatInfo = TokenInfo[PrevKind];
+
+  // If prevtok never causes a problem for anything after it, return quickly.
+  if (ConcatInfo == 0) return false;
+
+  if (ConcatInfo & aci_avoid_equal) {
+    // If the next token is '=' or '==', avoid concatenation.
+    if (Tok.is(tok::equal) || Tok.is(tok::equalequal))
+      return true;
+    ConcatInfo &= ~aci_avoid_equal;
+  }
+
+  if (ConcatInfo == 0) return false;
+
+  // Basic algorithm: we look at the first character of the second token, and
+  // determine whether it, if appended to the first token, would form (or
+  // would contribute) to a larger token if concatenated.
+  char FirstChar = 0;
+  if (ConcatInfo & aci_custom) {
+    // If the token does not need to know the first character, don't get it.
+  } else {
+    FirstChar = GetFirstChar(PP, Tok);
+  }
+
+  switch (PrevKind) {
+  default:
+    llvm_unreachable("InitAvoidConcatTokenInfo built wrong");
+
+  case tok::raw_identifier:
+    llvm_unreachable("tok::raw_identifier in non-raw lexing mode!");
+
+  case tok::string_literal:
+  case tok::wide_string_literal:
+  case tok::utf8_string_literal:
+  case tok::utf16_string_literal:
+  case tok::utf32_string_literal:
+  case tok::char_constant:
+  case tok::wide_char_constant:
+  case tok::utf16_char_constant:
+  case tok::utf32_char_constant:
+    if (!PP.getLangOpts().CPlusPlus0x)
+      return false;
+
+    // In C++11, a string or character literal followed by an identifier is a
+    // single token.
+    if (Tok.getIdentifierInfo())
+      return true;
+
+    // A ud-suffix is an identifier. If the previous token ends with one, treat
+    // it as an identifier.
+    if (!PrevTok.hasUDSuffix())
+      return false;
+    // FALL THROUGH.
+  case tok::identifier:   // id+id or id+number or id+L"foo".
+    // id+'.'... will not append.
+    if (Tok.is(tok::numeric_constant))
+      return GetFirstChar(PP, Tok) != '.';
+
+    if (Tok.getIdentifierInfo() || Tok.is(tok::wide_string_literal) ||
+        Tok.is(tok::utf8_string_literal) || Tok.is(tok::utf16_string_literal) ||
+        Tok.is(tok::utf32_string_literal) || Tok.is(tok::wide_char_constant) ||
+        Tok.is(tok::utf16_char_constant) || Tok.is(tok::utf32_char_constant))
+      return true;
+
+    // If this isn't identifier + string, we're done.
+    if (Tok.isNot(tok::char_constant) && Tok.isNot(tok::string_literal))
+      return false;
+
+    // Otherwise, this is a narrow character or string.  If the *identifier*
+    // is a literal 'L', 'u8', 'u' or 'U', avoid pasting L "foo" -> L"foo".
+    return IsIdentifierStringPrefix(PrevTok);
+
+  case tok::numeric_constant:
+    return isalnum(FirstChar) || Tok.is(tok::numeric_constant) ||
+           FirstChar == '+' || FirstChar == '-' || FirstChar == '.' ||
+           (PP.getLangOpts().CPlusPlus0x && FirstChar == '_');
+  case tok::period:          // ..., .*, .1234
+    return (FirstChar == '.' && PrevPrevTok.is(tok::period)) ||
+    isdigit(FirstChar) ||
+    (PP.getLangOpts().CPlusPlus && FirstChar == '*');
+  case tok::amp:             // &&
+    return FirstChar == '&';
+  case tok::plus:            // ++
+    return FirstChar == '+';
+  case tok::minus:           // --, ->, ->*
+    return FirstChar == '-' || FirstChar == '>';
+  case tok::slash:           //, /*, //
+    return FirstChar == '*' || FirstChar == '/';
+  case tok::less:            // <<, <<=, <:, <%
+    return FirstChar == '<' || FirstChar == ':' || FirstChar == '%';
+  case tok::greater:         // >>, >>=
+    return FirstChar == '>';
+  case tok::pipe:            // ||
+    return FirstChar == '|';
+  case tok::percent:         // %>, %:
+    return FirstChar == '>' || FirstChar == ':';
+  case tok::colon:           // ::, :>
+    return FirstChar == '>' ||
+    (PP.getLangOpts().CPlusPlus && FirstChar == ':');
+  case tok::hash:            // ##, #@, %:%:
+    return FirstChar == '#' || FirstChar == '@' || FirstChar == '%';
+  case tok::arrow:           // ->*
+    return PP.getLangOpts().CPlusPlus && FirstChar == '*';
+  }
+}