[ms-inline-asm] Cleanup MS style inline assembly parsing.

Specifically, improve the handling of whitespace, stop saving tokens that are
in comments and fix the case where we have a comment followed by a closing brace
on the next line.

Unfortunately, there's no easy way of testing this code.

llvm-svn: 158367

clang/lib/Parse/ParseStmt.cpp

@@ -1626,6 +1626,41 @@ StmtResult Parser::ParseReturnStatement() {
   return Actions.ActOnReturnStmt(ReturnLoc, R.take());
 }
 
+// needSpaceAsmToken - This function handles whitespace around asm punctuation.
+// Returns true if a space should be emitted.  
+static inline bool needSpaceAsmToken(Token currTok) {
+  static Token prevTok;
+
+  // No need for space after prevToken.
+  switch(prevTok.getKind()) {
+  default:
+    break;
+  case tok::l_square:
+  case tok::r_square:
+  case tok::l_brace:
+  case tok::r_brace:
+  case tok::colon:
+    prevTok = currTok;
+    return false;
+  }
+
+  // No need for a space before currToken.
+  switch(currTok.getKind()) {
+  default:
+    break;
+  case tok::l_square:
+  case tok::r_square:
+  case tok::l_brace:
+  case tok::r_brace:
+  case tok::comma:
+  case tok::colon:
+    prevTok = currTok;
+    return false;
+  }
+  prevTok = currTok;
+  return true;
+}
+
 /// ParseMicrosoftAsmStatement. When -fms-extensions/-fasm-blocks is enabled,
 /// this routine is called to collect the tokens for an MS asm statement.
 ///
@@ -1703,22 +1738,23 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
           // does MSVC do here?
           break;
         }
-      } else if (InBraces && Tok.is(tok::r_brace) &&
-                 BraceCount == savedBraceCount + 1) {
+      }
+      if (!InAsmComment && InBraces && Tok.is(tok::r_brace) &&
+          BraceCount == (savedBraceCount + 1)) {
         // Consume the closing brace, and finish
         EndLoc = ConsumeBrace();
         break;
       }
 
-      AsmToks.push_back(Tok);
-
       // Consume the next token; make sure we don't modify the brace count etc.
       // if we are in a comment.
       EndLoc = TokLoc;
       if (InAsmComment)
         PP.Lex(Tok);
-      else
+      else {
+        AsmToks.push_back(Tok);
         ConsumeAnyToken();
+      }
       TokLoc = Tok.getLocation();
       ++NumTokensRead;
     } while (1);
@@ -1747,14 +1783,15 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
   SmallString<512> TokenBuf;
   TokenBuf.resize(512);
   unsigned AsmLineNum = 0;
-  for (unsigned i = 0, e = AsmToks.size(); i < e; i++) {
+  for (unsigned i = 0, e = AsmToks.size(); i < e; ++i) {
     const char *ThisTokBuf = &TokenBuf[0];
     bool StringInvalid = false;
     unsigned ThisTokLen = 
       Lexer::getSpelling(AsmToks[i], ThisTokBuf, PP.getSourceManager(),
                          PP.getLangOpts(), &StringInvalid);
-    if (i && (!AsmLineNum || i != LineEnds[AsmLineNum-1]))
-      Asm += ' '; // FIXME: Too much whitespace around punctuation
+    if (i && (!AsmLineNum || i != LineEnds[AsmLineNum-1]) &&
+        needSpaceAsmToken(AsmToks[i]))
+      Asm += ' ';
     Asm += StringRef(ThisTokBuf, ThisTokLen);
     if (i + 1 == LineEnds[AsmLineNum] && i + 1 != AsmToks.size()) {
       Asm += '\n';
@@ -1766,7 +1803,7 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
   // (or possibly in addition to the) AsmString.  Sema is going to interact with
   // MC to determine Constraints, Clobbers, etc., which would be simplest to
   // do with the tokens.
-  std::string AsmString = Asm.data();
+  std::string AsmString = Asm.c_str();
   return Actions.ActOnMSAsmStmt(AsmLoc, AsmString, EndLoc);
 }
 

clang/test/Parser/ms-inline-asm.c

@@ -20,6 +20,13 @@ int t6() {
   __asm int 4
   return 10;
 }
-int t7() { // expected-note {{to match this}}
+int t7() {
+  __asm {
+    push ebx
+    mov ebx, 0x07
+    pop ebx
+  }
+}
+int t_fail() { // expected-note {{to match this}}
   __asm
   __asm { // expected-error 3 {{expected}} expected-note {{to match this}}