Prefer not to break after assignments.

This addresses llvm.org/PR14830.

Before:
unsigned Cost =
    TTI.getMemoryOpCost(I->getOpcode(), VectorTy, SI->getAlignment(),
                        SI->getPointerAddressSpace());
CharSourceRange LineRange =
    CharSourceRange::getTokenRange(TheLine.Tokens.front().Tok.getLocation(),
                                   TheLine.Tokens.back().Tok.getLocation());

After:
unsigned Cost = TTI.getMemoryOpCost(I->getOpcode(), VectorTy,
                                    SI->getAlignment(),
                                    SI->getPointerAddressSpace());
CharSourceRange LineRange = CharSourceRange::getTokenRange(
                                TheLine.Tokens.front().Tok.getLocation(),
                                TheLine.Tokens.back().Tok.getLocation());

This required rudimentary changes to static initializer lists, but we
are not yet formatting them in a reasonable way. That will be done in a
subsequent patch.

llvm-svn: 171731

clang/lib/Format/Format.cpp

@@ -257,7 +257,12 @@ private:
 
     if (Newline) {
       unsigned WhitespaceStartColumn = State.Column;
-      if (Current.Tok.is(tok::string_literal) &&
+      if (Previous.Tok.is(tok::l_brace)) {
+        // FIXME: This does not work with nested static initializers.
+        // Implement a better handling for static initializers and similar
+        // constructs.
+        State.Column = Line.Level * 2 + 2;
+      } else if (Current.Tok.is(tok::string_literal) &&
           Previous.Tok.is(tok::string_literal)) {
         State.Column = State.Column - Previous.TokenLength;
       } else if (Current.Tok.is(tok::lessless) &&
@@ -306,17 +311,19 @@ private:
       if (!DryRun)
         replaceWhitespace(Current, 0, Spaces);
 
-      // FIXME: Look into using this alignment at other ParenLevels.
+      if (Line.Tokens[0].Tok.isNot(tok::kw_for) &&
-      if (ParenLevel == 0 && (getPrecedence(Previous) == prec::Assignment ||
+          (getPrecedence(Previous) == prec::Assignment ||
-                              Previous.Tok.is(tok::kw_return)))
+           Previous.Tok.is(tok::kw_return)))
         State.Indent[ParenLevel] = State.Column + Spaces;
       if (Previous.Tok.is(tok::l_paren) ||
           Annotations[Index - 1].Type == TT_TemplateOpener)
         State.Indent[ParenLevel] = State.Column;
 
-      // Top-level spaces are exempt as that mostly leads to better results.
+      // Top-level spaces that are not part of assignments are exempt as that
+      // mostly leads to better results.
       State.Column += Spaces;
-      if (Spaces > 0 && ParenLevel != 0)
+      if (Spaces > 0 &&
+          (ParenLevel != 0 || getPrecedence(Previous) == prec::Assignment))
         State.LastSpace[ParenLevel] = State.Column;
     }
     moveStateToNextToken(State);
@@ -375,7 +382,13 @@ private:
     if (Left.Tok.is(tok::l_paren))
       return 20;
 
-    prec::Level Level = getPrecedence(Line.Tokens[Index]);
+    prec::Level Level = getPrecedence(Left);
+
+    // Breaking after an assignment leads to a bad result as the two sides of
+    // the assignment are visually very close together.
+    if (Level == prec::Assignment)
+      return 50;
+
     if (Level != prec::Unknown)
       return Level;
 

clang/unittests/Format/FormatTest.cpp

@@ -384,8 +384,8 @@ TEST_F(FormatTest, StaticInitializers) {
 
   // FIXME: Format like enums if the static initializer does not fit on a line.
   verifyFormat(
-      "static SomeClass WithALoooooooooooooooooooongName = { 100000000,\n"
+      "static SomeClass WithALoooooooooooooooooooongName = {\n"
-      "    \"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\" };");
+      "  100000000, \"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\" };");
 }
 
 TEST_F(FormatTest, FormatsSmallMacroDefinitionsInSingleLine) {
@@ -641,6 +641,17 @@ TEST_F(FormatTest, BreaksAccordingToOperatorPrecedence) {
       "    ccccccccccccccccccccccccc) {\n}");
 }
 
+TEST_F(FormatTest, PrefersNotToBreakAfterAssignments) {
+  verifyFormat(
+      "unsigned Cost = TTI.getMemoryOpCost(I->getOpcode(), VectorTy,\n"
+      "                                    SI->getAlignment(),\n"
+      "                                    SI->getPointerAddressSpaceee());\n");
+  verifyFormat(
+      "CharSourceRange LineRange = CharSourceRange::getTokenRange(\n"
+      "                                Line.Tokens.front().Tok.getLocation(),\n"
+      "                                Line.Tokens.back().Tok.getLocation());");
+}
+
 TEST_F(FormatTest, AlignsAfterAssignments) {
   verifyFormat(
       "int Result = aaaaaaaaaaaaaaaaaaaaaaaaa + aaaaaaaaaaaaaaaaaaaaaaaaa +\n"
@@ -655,9 +666,9 @@ TEST_F(FormatTest, AlignsAfterAssignments) {
       "int Result = (aaaaaaaaaaaaaaaaaaaaaaaaa + aaaaaaaaaaaaaaaaaaaaaaaaa +\n"
       "              aaaaaaaaaaaaaaaaaaaaaaaaa);");
   verifyFormat(
-      "double LooooooooooooooooooooooooongResult =\n"
+      "double LooooooooooooooooooooooooongResult = aaaaaaaaaaaaaaaaaaaaaaaa +\n"
-      "    aaaaaaaaaaaaaaaaaaaaaaaaa + aaaaaaaaaaaaaaaaaaaaaaaaa +\n"
+      "                                            aaaaaaaaaaaaaaaaaaaaaaaa +\n"
-      "    aaaaaaaaaaaaaaaaaaaaaaaaa;"); 
+      "                                            aaaaaaaaaaaaaaaaaaaaaaaa;");
 }
 
 TEST_F(FormatTest, AlignsAfterReturn) {
@@ -713,8 +724,10 @@ TEST_F(FormatTest, UnderstandsEquals) {
       "               aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {\n"
       "}");
 
-  verifyFormat("if (int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa =\n"
+  verifyFormat(
-               "        100000000 + 100000000) {\n}");
+      "if (int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa = 100000000 +\n"
+      "                                                           10000000) {\n"
+      "}");
 }
 
 TEST_F(FormatTest, WrapsAtFunctionCallsIfNecessary) {