clang-cl: Merge adjacent single-line __asm blocks

Summary:
This patch extends the __asm parser to make it keep parsing input tokens
as inline assembly if a single-line __asm line is followed by another line
starting with __asm too.  It also makes sure that we correctly keep
matching braces in such situations by separating the notions of how many
braces we are matching and whether we are in single-line asm block mode.

Reviewers: rnk

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4598

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213916 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 9 deletions

diff --git a/lib/Parse/ParseStmtAsm.cpp b/lib/Parse/ParseStmtAsm.cpp
index 58d69965de..f1d2946e0e 100644
--- a/lib/Parse/ParseStmtAsm.cpp
+++ b/lib/Parse/ParseStmtAsm.cpp
@@ -322,6 +322,7 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
   SourceLocation EndLoc = AsmLoc;
   SmallVector<Token, 4> AsmToks;
 
+  bool SingleLineMode = true;
   unsigned BraceNesting = 0;
   unsigned short savedBraceCount = BraceCount;
   bool InAsmComment = false;
@@ -333,6 +334,7 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
 
   if (Tok.is(tok::l_brace)) {
     // Braced inline asm: consume the opening brace.
+    SingleLineMode = false;
     BraceNesting = 1;
     EndLoc = ConsumeBrace();
     LBraceLocs.push_back(EndLoc);
@@ -364,30 +366,39 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
     } else if (!InAsmComment && Tok.is(tok::semi)) {
       // A semicolon in an asm is the start of a comment.
       InAsmComment = true;
-      if (BraceNesting) {
+      if (!SingleLineMode) {
         // Compute which line the comment is on.
         std::pair<FileID, unsigned> ExpSemiLoc =
             SrcMgr.getDecomposedExpansionLoc(TokLoc);
         FID = ExpSemiLoc.first;
         LineNo = SrcMgr.getLineNumber(FID, ExpSemiLoc.second);
       }
-    } else if (!BraceNesting || InAsmComment) {
+    } else if (SingleLineMode || InAsmComment) {
       // If end-of-line is significant, check whether this token is on a
       // new line.
       std::pair<FileID, unsigned> ExpLoc =
           SrcMgr.getDecomposedExpansionLoc(TokLoc);
       if (ExpLoc.first != FID ||
           SrcMgr.getLineNumber(ExpLoc.first, ExpLoc.second) != LineNo) {
-        // If this is a single-line __asm, we're done.
-        if (!BraceNesting)
+        // If this is a single-line __asm, we're done, except if the next
+        // line begins with an __asm too, in which case we finish a comment
+        // if needed and then keep processing the next line as a single
+        // line __asm.
+        bool isAsm = Tok.is(tok::kw_asm);
+        if (SingleLineMode && !isAsm)
           break;
         // We're no longer in a comment.
         InAsmComment = false;
+        if (isAsm) {
+          LineNo = SrcMgr.getLineNumber(ExpLoc.first, ExpLoc.second);
+          SkippedStartOfLine = Tok.isAtStartOfLine();
+        }
       } else if (!InAsmComment && Tok.is(tok::r_brace)) {
-        // Single-line asm always ends when a closing brace is seen.
-        // FIXME: This is compatible with Apple gcc's -fasm-blocks; what
-        // does MSVC do here?
-        break;
+        // In MSVC mode, braces only participate in brace matching and
+        // separating the asm statements.  This is an intentional
+        // departure from the Apple gcc behavior.
+        if (!BraceNesting)
+          break;
       }
     }
     if (!InAsmComment && BraceNesting && Tok.is(tok::r_brace) &&
@@ -398,7 +409,7 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
       BraceNesting--;
       // Finish if all of the opened braces in the inline asm section were
       // consumed.
-      if (BraceNesting == 0)
+      if (BraceNesting == 0 && !SingleLineMode)
         break;
       else {
         LBraceLocs.pop_back();