factor token concatenation avoidance logic out of

PrintPreprocessedOutput into its own file.  No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64418 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 205 insertions, 0 deletions

diff --git a/lib/Lex/TokenConcatenation.cpp b/lib/Lex/TokenConcatenation.cpp
new file mode 100644
index 0000000000..549fb8d088
--- /dev/null
+++ b/lib/Lex/TokenConcatenation.cpp
@@ -0,0 +1,205 @@
+//===--- 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"
+using namespace clang; 
+
+
+/// StartsWithL - Return true if the spelling of this token starts with 'L'.
+bool TokenConcatenation::StartsWithL(const Token &Tok) const {
+  if (!Tok.needsCleaning()) {
+    SourceManager &SM = PP.getSourceManager();
+    return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())) == 'L';
+  }
+  
+  if (Tok.getLength() < 256) {
+    char Buffer[256];
+    const char *TokPtr = Buffer;
+    PP.getSpelling(Tok, TokPtr);
+    return TokPtr[0] == 'L';
+  }
+  
+  return PP.getSpelling(Tok)[0] == 'L';
+}
+
+/// IsIdentifierL - Return true if the spelling of this token is literally
+/// 'L'.
+bool TokenConcatenation::IsIdentifierL(const Token &Tok) const {
+  if (!Tok.needsCleaning()) {
+    if (Tok.getLength() != 1)
+      return false;
+    SourceManager &SM = PP.getSourceManager();
+    return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())) == 'L';
+  }
+  
+  if (Tok.getLength() < 256) {
+    char Buffer[256];
+    const char *TokPtr = Buffer;
+    if (PP.getSpelling(Tok, TokPtr) != 1) 
+      return false;
+    return TokPtr[0] == 'L';
+  }
+  
+  return PP.getSpelling(Tok) == "L";
+}
+
+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 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::greaterequal] |= aci_avoid_equal;           // >>=
+  TokenInfo[tok::caret       ] |= aci_avoid_equal;           // ^=
+  TokenInfo[tok::equal       ] |= aci_avoid_equal;           // ==
+}
+
+/// 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 &PrevTok,
+                                     const Token &Tok) const {
+  char Buffer[256];
+  
+  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 if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
+    // Avoid spelling identifiers, the most common form of token.
+    FirstChar = II->getName()[0];
+  } else if (!Tok.needsCleaning()) {
+    if (Tok.isLiteral() && Tok.getLiteralData()) {
+      FirstChar = *Tok.getLiteralData();
+    } else {
+      SourceManager &SrcMgr = PP.getSourceManager();
+      FirstChar =
+      *SrcMgr.getCharacterData(SrcMgr.getSpellingLoc(Tok.getLocation()));
+    }
+  } else if (Tok.getLength() < 256) {
+    const char *TokPtr = Buffer;
+    PP.getSpelling(Tok, TokPtr);
+    FirstChar = TokPtr[0];
+  } else {
+    FirstChar = PP.getSpelling(Tok)[0];
+  }
+  
+  switch (PrevKind) {
+  default: assert(0 && "InitAvoidConcatTokenInfo built wrong");
+  case tok::identifier:   // id+id or id+number or id+L"foo".
+    if (Tok.is(tok::numeric_constant) || Tok.getIdentifierInfo() ||
+        Tok.is(tok::wide_string_literal) /* ||
+     Tok.is(tok::wide_char_literal)*/)
+      return true;
+    
+    // If this isn't identifier + string, we're done.
+    if (Tok.isNot(tok::char_constant) && Tok.isNot(tok::string_literal))
+      return false;
+    
+    // FIXME: need a wide_char_constant!
+    
+    // If the string was a wide string L"foo" or wide char L'f', it would
+    // concat with the previous identifier into fooL"bar".  Avoid this.
+    if (StartsWithL(Tok))
+      return true;
+    
+    // Otherwise, this is a narrow character or string.  If the *identifier*
+    // is a literal 'L', avoid pasting L "foo" -> L"foo".
+    return IsIdentifierL(PrevTok);
+  case tok::numeric_constant:
+    return isalnum(FirstChar) || Tok.is(tok::numeric_constant) ||
+    FirstChar == '+' || FirstChar == '-' || FirstChar == '.';
+  case tok::period:          // ..., .*, .1234
+    return FirstChar == '.' || isdigit(FirstChar) ||
+    (FirstChar == '*' && PP.getLangOptions().CPlusPlus);
+  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 == ':') &&
+    PP.getLangOptions().Digraphs;
+  case tok::colon:           // ::, :>
+    return (FirstChar == ':' && PP.getLangOptions().CPlusPlus) ||
+    (FirstChar == '>' && PP.getLangOptions().Digraphs);
+  case tok::hash:            // ##, #@, %:%:
+    return FirstChar == '#' || FirstChar == '@' || FirstChar == '%';
+  case tok::arrow:           // ->*
+    return FirstChar == '*';
+  }
+}