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

6 files changed, 37 insertions, 6 deletions

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 0637f76f07c..adc19fb11a3 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -469,6 +469,7 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("SpacesInParentheses", Style.SpacesInParentheses);
     IO.mapOptional("SpacesInSquareBrackets", Style.SpacesInSquareBrackets);
     IO.mapOptional("Standard", Style.Standard);
+    IO.mapOptional("StatementMacros", Style.StatementMacros);
     IO.mapOptional("TabWidth", Style.TabWidth);
     IO.mapOptional("UseTab", Style.UseTab);
   }
@@ -714,6 +715,8 @@ FormatStyle getLLVMStyle() {
   LLVMStyle.DisableFormat = false;
   LLVMStyle.SortIncludes = true;
   LLVMStyle.SortUsingDeclarations = true;
+  LLVMStyle.StatementMacros.push_back("Q_UNUSED");
+  LLVMStyle.StatementMacros.push_back("QT_REQUIRE_VERSION");
 
   return LLVMStyle;
 }
diff --git a/clang/lib/Format/FormatToken.h b/clang/lib/Format/FormatToken.h
index f65fe5b0049..6e801a346b8 100644
--- a/clang/lib/Format/FormatToken.h
+++ b/clang/lib/Format/FormatToken.h
@@ -86,6 +86,7 @@ namespace format {
   TYPE(RegexLiteral)                                                           \
   TYPE(SelectorName)                                                           \
   TYPE(StartOfName)                                                            \
+  TYPE(StatementMacro)                                                         \
   TYPE(StructuredBindingLSquare)                                               \
   TYPE(TemplateCloser)                                                         \
   TYPE(TemplateOpener)                                                         \
diff --git a/clang/lib/Format/FormatTokenLexer.cpp b/clang/lib/Format/FormatTokenLexer.cpp
index 7f2edf102c7..146f5d68b55 100644
--- a/clang/lib/Format/FormatTokenLexer.cpp
+++ b/clang/lib/Format/FormatTokenLexer.cpp
@@ -37,8 +37,9 @@ FormatTokenLexer::FormatTokenLexer(const SourceManager &SourceMgr, FileID ID,
   Lex->SetKeepWhitespaceMode(true);
 
   for (const std::string &ForEachMacro : Style.ForEachMacros)
-    ForEachMacros.push_back(&IdentTable.get(ForEachMacro));
-  llvm::sort(ForEachMacros);
+    Macros.insert({&IdentTable.get(ForEachMacro), TT_ForEachMacro});
+  for (const std::string &StatementMacro : Style.StatementMacros)
+    Macros.insert({&IdentTable.get(StatementMacro), TT_StatementMacro});
 }
 
 ArrayRef<FormatToken *> FormatTokenLexer::lex() {
@@ -657,12 +658,12 @@ FormatToken *FormatTokenLexer::getNextToken() {
   }
 
   if (Style.isCpp()) {
+    auto it = Macros.find(FormatTok->Tok.getIdentifierInfo());
     if (!(Tokens.size() > 0 && Tokens.back()->Tok.getIdentifierInfo() &&
           Tokens.back()->Tok.getIdentifierInfo()->getPPKeywordID() ==
               tok::pp_define) &&
-        std::find(ForEachMacros.begin(), ForEachMacros.end(),
-                  FormatTok->Tok.getIdentifierInfo()) != ForEachMacros.end()) {
-      FormatTok->Type = TT_ForEachMacro;
+        it != Macros.end()) {
+      FormatTok->Type = it->second;
     } else if (FormatTok->is(tok::identifier)) {
       if (MacroBlockBeginRegex.match(Text)) {
         FormatTok->Type = TT_MacroBlockBegin;
diff --git a/clang/lib/Format/FormatTokenLexer.h b/clang/lib/Format/FormatTokenLexer.h
index 3b79d27480e..0cf357c85f3 100644
--- a/clang/lib/Format/FormatTokenLexer.h
+++ b/clang/lib/Format/FormatTokenLexer.h
@@ -22,6 +22,7 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Format/Format.h"
 #include "llvm/Support/Regex.h"
+#include "llvm/ADT/MapVector.h"
 
 #include <stack>
 
@@ -99,7 +100,8 @@ private:
   // Index (in 'Tokens') of the last token that starts a new line.
   unsigned FirstInLineIndex;
   SmallVector<FormatToken *, 16> Tokens;
-  SmallVector<IdentifierInfo *, 8> ForEachMacros;
+
+  llvm::SmallMapVector<IdentifierInfo *, TokenType, 8> Macros;
 
   bool FormattingDisabled;
 
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
diff --git a/clang/lib/Format/UnwrappedLineParser.h b/clang/lib/Format/UnwrappedLineParser.h
index 87254832c63..55d60dff915 100644
--- a/clang/lib/Format/UnwrappedLineParser.h
+++ b/clang/lib/Format/UnwrappedLineParser.h
@@ -126,6 +126,7 @@ private:
   void parseObjCInterfaceOrImplementation();
   bool parseObjCProtocol();
   void parseJavaScriptEs6ImportExport();
+  void parseStatementMacro();
   bool tryToParseLambda();
   bool tryToParseLambdaIntroducer();
   void tryToParseJSFunction();