clang-format: better handle statement macros

Summary:
Some macros are used in the body of function, and actually contain the trailing semicolon: they should thus be automatically followed by a new line, and not get merged with the next line. This is for example the case with Qt's Q_UNUSED macro:

  void foo(int a, int b) {
    Q_UNUSED(a)
    return b;
  }

This patch deals with these cases by introducing a new option to specify list of statement macros. This re-uses the system already in place for foreach macros, to ensure there is no impact on performance.

Reviewers: krasimir, djasper, klimek

Reviewed By: krasimir

Subscribers: acoomans, mgrang, alexfh, klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D33440

llvm-svn: 343602

1 files changed, 23 insertions, 0 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 09cd660e6de..6c81d8b60e9 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -480,6 +480,10 @@ void UnwrappedLineParser::calculateBraceTypes(bool ExpectClassBody) {
       }
       LBraceStack.pop_back();
       break;
+    case tok::identifier:
+      if (!Tok->is(TT_StatementMacro))
+          break;
+      LLVM_FALLTHROUGH;
     case tok::at:
     case tok::semi:
     case tok::kw_if:
@@ -1108,6 +1112,10 @@ void UnwrappedLineParser::parseStructuralElement() {
         return;
       }
     }
+    if (Style.isCpp() && FormatTok->is(TT_StatementMacro)) {
+      parseStatementMacro();
+      return;
+    }
     // In all other cases, parse the declaration.
     break;
   default:
@@ -1309,6 +1317,11 @@ void UnwrappedLineParser::parseStructuralElement() {
         return;
       }
 
+      if (Style.isCpp() && FormatTok->is(TT_StatementMacro)) {
+        parseStatementMacro();
+        return;
+      }
+
       // See if the following token should start a new unwrapped line.
       StringRef Text = FormatTok->TokenText;
       nextToken();
@@ -2328,6 +2341,16 @@ void UnwrappedLineParser::parseJavaScriptEs6ImportExport() {
   }
 }
 
+void UnwrappedLineParser::parseStatementMacro()
+{
+  nextToken();
+  if (FormatTok->is(tok::l_paren))
+    parseParens();
+  if (FormatTok->is(tok::semi))
+    nextToken();
+  addUnwrappedLine();
+}
+
 LLVM_ATTRIBUTE_UNUSED static void printDebugInfo(const UnwrappedLine &Line,
                                                  StringRef Prefix = "") {
   llvm::dbgs() << Prefix << "Line(" << Line.Level