krasimir created this revision.
Herald added a subscriber: klimek.
This patch enables `BreakableToken` to manage the formatting of non-trailing
block comments. It is a refinement of https://reviews.llvm.org/D37007.
We discovered that the optimizer outsmarts us on cases where breaking the
comment
costs considerably less than breaking after the comment. This patch addresses
this by ensuring that a newline is inserted between a block comment and the next
token.
https://reviews.llvm.org/D37695
Files:
lib/Format/BreakableToken.cpp
lib/Format/BreakableToken.h
lib/Format/ContinuationIndenter.cpp
lib/Format/ContinuationIndenter.h
unittests/Format/FormatTestComments.cpp
unittests/Format/FormatTestJS.cpp
Index: unittests/Format/FormatTestJS.cpp
===================================================================
--- unittests/Format/FormatTestJS.cpp
+++ unittests/Format/FormatTestJS.cpp
@@ -65,6 +65,27 @@
TEST_F(FormatTestJS, BlockComments) {
verifyFormat("/* aaaaaaaaaaaaa */ aaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
" aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa);");
+ // Breaks after a single line block comment.
+ EXPECT_EQ("aaaaa = bbbb.ccccccccccccccc(\n"
+ " /** @type_{!cccc.rrrrrrr.MMMMMMMMMMMM.LLLLLLLLLLL.lala} */\n"
+ " mediaMessage);",
+ format("aaaaa = bbbb.ccccccccccccccc(\n"
+ " /** "
+ "@type_{!cccc.rrrrrrr.MMMMMMMMMMMM.LLLLLLLLLLL.lala} */ "
+ "mediaMessage);",
+ getGoogleJSStyleWithColumns(70)));
+ // Breaks after a multiline block comment.
+ EXPECT_EQ(
+ "aaaaa = bbbb.ccccccccccccccc(\n"
+ " /**\n"
+ " * @type_{!cccc.rrrrrrr.MMMMMMMMMMMM.LLLLLLLLLLL.lala}\n"
+ " */\n"
+ " mediaMessage);",
+ format("aaaaa = bbbb.ccccccccccccccc(\n"
+ " /**\n"
+ " * @type_{!cccc.rrrrrrr.MMMMMMMMMMMM.LLLLLLLLLLL.lala}\n"
+ " */ mediaMessage);",
+ getGoogleJSStyleWithColumns(70)));
}
TEST_F(FormatTestJS, JSDocComments) {
Index: unittests/Format/FormatTestComments.cpp
===================================================================
--- unittests/Format/FormatTestComments.cpp
+++ unittests/Format/FormatTestComments.cpp
@@ -2407,6 +2407,57 @@
getLLVMStyleWithColumns(15)));
}
+TEST_F(FormatTestComments, BreaksAfterMultilineBlockCommentsInParamLists) {
+ EXPECT_EQ("a = f(/* long\n"
+ " long\n"
+ " */\n"
+ " a);",
+ format("a = f(/* long long */ a);", getLLVMStyleWithColumns(15)));
+
+ EXPECT_EQ("a = f(/* long\n"
+ " long\n"
+ " */\n"
+ " a);",
+ format("a = f(/* long\n"
+ " long\n"
+ " */a);",
+ getLLVMStyleWithColumns(15)));
+
+ EXPECT_EQ("a = f(/* long\n"
+ " long\n"
+ " */\n"
+ " a);",
+ format("a = f(/* long\n"
+ " long\n"
+ " */ a);",
+ getLLVMStyleWithColumns(15)));
+
+ EXPECT_EQ("a = f(/* long\n"
+ " long\n"
+ " */\n"
+ " (1 + 1));",
+ format("a = f(/* long\n"
+ " long\n"
+ " */ (1 + 1));",
+ getLLVMStyleWithColumns(15)));
+
+ EXPECT_EQ(
+ "a = f(a,\n"
+ " /* long\n"
+ " long\n"
+ " */\n"
+ " b);",
+ format("a = f(a, /* long long */ b);", getLLVMStyleWithColumns(15)));
+
+ EXPECT_EQ(
+ "a = f(a,\n"
+ " /* long\n"
+ " long\n"
+ " */\n"
+ " (1 + 1));",
+ format("a = f(a, /* long long */ (1 + 1));", getLLVMStyleWithColumns(15)));
+}
+
TEST_F(FormatTestComments, IndentLineCommentsInStartOfBlockAtEndOfFile) {
verifyFormat("{\n"
" // a\n"
Index: lib/Format/ContinuationIndenter.h
===================================================================
--- lib/Format/ContinuationIndenter.h
+++ lib/Format/ContinuationIndenter.h
@@ -154,7 +154,8 @@
NoLineBreakInOperand(false), LastOperatorWrapped(true),
ContainsLineBreak(false), ContainsUnwrappedBuilder(false),
AlignColons(true), ObjCSelectorNameFound(false),
- HasMultipleNestedBlocks(false), NestedBlockInlined(false) {}
+ HasMultipleNestedBlocks(false), NestedBlockInlined(false),
+ LastBlockCommentWasBroken(false) {}
/// \brief The position to which a specific parenthesis level needs to be
/// indented.
@@ -264,6 +265,10 @@
// "function" in JavaScript) is not wrapped to a new line.
bool NestedBlockInlined : 1;
+ // \brief \c true if the last block comment on this level was broken by
+ // \c breakProtrudingToken.
+ bool LastBlockCommentWasBroken : 1;
+
bool operator<(const ParenState &Other) const {
if (Indent != Other.Indent)
return Indent < Other.Indent;
@@ -301,6 +306,8 @@
return ContainsUnwrappedBuilder;
if (NestedBlockInlined != Other.NestedBlockInlined)
return NestedBlockInlined;
+ if (LastBlockCommentWasBroken != Other.LastBlockCommentWasBroken)
+ return LastBlockCommentWasBroken;
return false;
}
};
Index: lib/Format/ContinuationIndenter.cpp
===================================================================
--- lib/Format/ContinuationIndenter.cpp
+++ lib/Format/ContinuationIndenter.cpp
@@ -323,6 +323,9 @@
Previous.TokenText == "\'\\n\'"))))
return true;
+ if (Previous.is(TT_BlockComment) &&
+ (Previous.IsMultiline || State.Stack.back().LastBlockCommentWasBroken))
+ return true;
return false;
}
@@ -1286,7 +1289,7 @@
return 0;
}
} else if (Current.is(TT_BlockComment)) {
- if (!Current.isTrailingComment() || !Style.ReflowComments ||
+ if (!Style.ReflowComments ||
// If a comment token switches formatting, like
// /* clang-format on */, we don't want to break it further,
// but we may still want to adjust its indentation.
@@ -1332,6 +1335,7 @@
ReflowInProgress = SplitBefore.first != StringRef::npos;
TailOffset =
ReflowInProgress ? (SplitBefore.first + SplitBefore.second) : 0;
+ BreakInserted = BreakInserted || Token->introducesBreakBefore(LineIndex);
if (!DryRun)
Token->replaceWhitespaceBefore(LineIndex, RemainingTokenColumns,
RemainingSpace, SplitBefore, Whitespaces);
@@ -1408,6 +1412,9 @@
State.Stack[i].BreakBeforeParameter = true;
}
+ if (Current.is(TT_BlockComment))
+ State.Stack.back().LastBlockCommentWasBroken = true;
+
Penalty += Current.isStringLiteral() ? Style.PenaltyBreakString
: Style.PenaltyBreakComment;
Index: lib/Format/BreakableToken.h
===================================================================
--- lib/Format/BreakableToken.h
+++ lib/Format/BreakableToken.h
@@ -58,6 +58,8 @@
/// operations that might be executed before the main line breaking occurs:
/// - getSplitBefore, for finding a split such that the content preceding it
/// needs to be specially reflown,
+/// - introducesBreakBefore, for checking if reformatting the beginning
+/// of the content introduces a line break before it,
/// - getLineLengthAfterSplitBefore, for calculating the line length in columns
/// of the remainder of the content after the beginning of the content has
/// been reformatted, and
@@ -135,6 +137,12 @@
return Split(StringRef::npos, 0);
}
+ /// \brief Returns if a break before the content at \p LineIndex will be
+ /// inserted after the whitespace preceding the content has been reformatted.
+ virtual bool introducesBreakBefore(unsigned LineIndex) const {
+ return false;
+ }
+
/// \brief Returns the number of columns required to format the piece of line
/// at \p LineIndex after the content preceding the whitespace range specified
/// \p SplitBefore has been reformatted, but before any breaks are made to
@@ -339,6 +347,7 @@
Split getSplitBefore(unsigned LineIndex, unsigned PreviousEndColumn,
unsigned ColumnLimit,
llvm::Regex &CommentPragmasRegex) const override;
+ bool introducesBreakBefore(unsigned LineIndex) const override;
unsigned getLineLengthAfterSplitBefore(unsigned LineIndex,
unsigned TailOffset,
unsigned PreviousEndColumn,
Index: lib/Format/BreakableToken.cpp
===================================================================
--- lib/Format/BreakableToken.cpp
+++ lib/Format/BreakableToken.cpp
@@ -602,6 +602,12 @@
}
}
+bool BreakableBlockComment::introducesBreakBefore(unsigned LineIndex) const {
+ // A break is introduced when we want delimiters on newline.
+ return LineIndex == 0 && DelimitersOnNewline &&
+ Lines[0].substr(1).find_first_not_of(Blanks) != StringRef::npos;
+}
+
void BreakableBlockComment::replaceWhitespaceBefore(
unsigned LineIndex, unsigned PreviousEndColumn, unsigned ColumnLimit,
Split SplitBefore, WhitespaceManager &Whitespaces) {
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