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clang-format: Handle "if constexpr". 

c++1z adds the following constructions to the language:

  if constexpr (cond)
    statement1;
  else if constexpr (cond)
    statement2;
  else if constexpr (cond)
    statement3;
  else
    statement4;

A first version of this was proposed in reviews.llvm.org/D26953 by
Francis Visoiu Mistrih, but never commited. This patch additionally
fixes the behavior when allowing short if statements on a single line
and was authored by Jacob Bandes-Storch. Thank you to both authors.

llvm-svn: 305666
This commit is contained in:
Daniel Jasper 2017-06-19 07:40:49 +00:00
parent 271dd0603e
commit 6a7d5a7a22
4 changed files with 78 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
clang/lib/Format/ContinuationIndenter.cpp
View File

@ -453,7 +453,8 @@ void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
State.Column += Spaces;
if (Current.isNot(tok::comment) && Previous.is(tok::l_paren) &&
Previous.Previous &&
Previous.Previous->isOneOf(tok::kw_if, tok::kw_for)) {
(Previous.Previous->isOneOf(tok::kw_if, tok::kw_for) ||
Previous.Previous->endsSequence(tok::kw_constexpr, tok::kw_if))) {
// Treat the condition inside an if as if it was a second function
// parameter, i.e. let nested calls have a continuation indent.
State.Stack.back().LastSpace = State.Column;

7
clang/lib/Format/TokenAnnotator.cpp
View File

@ -145,6 +145,7 @@ private:
(Left->Previous->isOneOf(tok::kw_static_assert, tok::kw_decltype,
tok::kw_if, tok::kw_while, tok::l_paren,
tok::comma) ||
Left->Previous->endsSequence(tok::kw_constexpr, tok::kw_if) ||
Left->Previous->is(TT_BinaryOperator))) {
// static_assert, if and while usually contain expressions.
Contexts.back().IsExpression = true;
@ -572,6 +573,8 @@ private:
break;
case tok::kw_if:
case tok::kw_while:
if (Tok->is(tok::kw_if) && CurrentToken && CurrentToken->is(tok::kw_constexpr))
next();
if (CurrentToken && CurrentToken->is(tok::l_paren)) {
next();
if (!parseParens(/*LookForDecls=*/true))
@ -2060,7 +2063,8 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
Style.AlignAfterOpenBracket != FormatStyle::BAS_DontAlign)
return 100;
if (Left.is(tok::l_paren) && Left.Previous &&
Left.Previous->isOneOf(tok::kw_if, tok::kw_for))
(Left.Previous->isOneOf(tok::kw_if, tok::kw_for)
|| Left.Previous->endsSequence(tok::kw_constexpr, tok::kw_if)))
return 1000;
if (Left.is(tok::equal) && InFunctionDecl)
return 110;
@ -2211,6 +2215,7 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
(Left.isOneOf(tok::kw_if, tok::pp_elif, tok::kw_for, tok::kw_while,
tok::kw_switch, tok::kw_case, TT_ForEachMacro,
TT_ObjCForIn) ||
Left.endsSequence(tok::kw_constexpr, tok::kw_if) ||
(Left.isOneOf(tok::kw_try, Keywords.kw___except, tok::kw_catch,
tok::kw_new, tok::kw_delete) &&
(!Left.Previous || Left.Previous->isNot(tok::period))))) ||

2
clang/lib/Format/UnwrappedLineParser.cpp
View File

@ -1516,6 +1516,8 @@ void UnwrappedLineParser::parseSquare() {
void UnwrappedLineParser::parseIfThenElse() {
assert(FormatTok->Tok.is(tok::kw_if) && "'if' expected");
nextToken();
if (FormatTok->Tok.is(tok::kw_constexpr))
nextToken();
if (FormatTok->Tok.is(tok::l_paren))
parseParens();
bool NeedsUnwrappedLine = false;

68
clang/unittests/Format/FormatTest.cpp
View File

@ -341,6 +341,18 @@ TEST_F(FormatTest, FormatIfWithoutCompoundStatement) {
verifyFormat("if (true)\n f();\ng();");
verifyFormat("if (a)\n if (b)\n if (c)\n g();\nh();");
verifyFormat("if (a)\n if (b) {\n f();\n }\ng();");
verifyFormat("if constexpr (true)\n"
" f();\ng();");
verifyFormat("if constexpr (a)\n"
" if constexpr (b)\n"
" if constexpr (c)\n"
" g();\n"
"h();");
verifyFormat("if constexpr (a)\n"
" if constexpr (b) {\n"
" f();\n"
" }\n"
"g();");
FormatStyle AllowsMergedIf = getLLVMStyle();
AllowsMergedIf.AlignEscapedNewlines = FormatStyle::ENAS_Left;
@ -423,9 +435,11 @@ TEST_F(FormatTest, FormatShortBracedStatements) {
AllowSimpleBracedStatements.AllowShortLoopsOnASingleLine = true;
verifyFormat("if (true) {}", AllowSimpleBracedStatements);
verifyFormat("if constexpr (true) {}", AllowSimpleBracedStatements);
verifyFormat("while (true) {}", AllowSimpleBracedStatements);
verifyFormat("for (;;) {}", AllowSimpleBracedStatements);
verifyFormat("if (true) { f(); }", AllowSimpleBracedStatements);
verifyFormat("if constexpr (true) { f(); }", AllowSimpleBracedStatements);
verifyFormat("while (true) { f(); }", AllowSimpleBracedStatements);
verifyFormat("for (;;) { f(); }", AllowSimpleBracedStatements);
verifyFormat("if (true) { //\n"
@ -496,6 +510,19 @@ TEST_F(FormatTest, ParseIfElse) {
"else {\n"
" i();\n"
"}");
verifyFormat("if (true)\n"
" if constexpr (true)\n"
" if (true) {\n"
" if constexpr (true)\n"
" f();\n"
" } else {\n"
" g();\n"
" }\n"
" else\n"
" h();\n"
"else {\n"
" i();\n"
"}");
verifyFormat("void f() {\n"
" if (a) {\n"
" } else {\n"
@ -511,6 +538,12 @@ TEST_F(FormatTest, ElseIf) {
" g();\n"
"else\n"
" h();");
verifyFormat("if constexpr (a)\n"
" f();\n"
"else if constexpr (b)\n"
" g();\n"
"else\n"
" h();");
verifyFormat("if (a) {\n"
" f();\n"
"}\n"
@ -528,6 +561,11 @@ TEST_F(FormatTest, ElseIf) {
" aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {\n"
"}",
getLLVMStyleWithColumns(62));
verifyFormat("if (a) {\n"
"} else if constexpr (\n"
" aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {\n"
"}",
getLLVMStyleWithColumns(62));
}
TEST_F(FormatTest, FormatsForLoop) {
@ -2506,6 +2544,9 @@ TEST_F(FormatTest, LineBreakingInBinaryExpressions) {
verifyFormat("if ((aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ||\n"
" bbbbbbbbbbbbbbbbbb) && // aaaaaaaaaaaaaaaa\n"
" cccccc) {\n}");
verifyFormat("if constexpr ((aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ||\n"
" bbbbbbbbbbbbbbbbbb) && // aaaaaaaaaaa\n"
" cccccc) {\n}");
verifyFormat("b = a &&\n"
" // Comment\n"
" b.c && d;");
@ -6627,6 +6668,10 @@ TEST_F(FormatTest, MergeHandlingInTheFaceOfPreprocessorDirectives) {
" if (true) continue;\n"
"}",
ShortMergedIf);
ShortMergedIf.ColumnLimit = 33;
verifyFormat("#define A \\\n"
" if constexpr (true) return 42;",
ShortMergedIf);
ShortMergedIf.ColumnLimit = 29;
verifyFormat("#define A \\\n"
" if (aaaaaaaaaa) return 1; \\\n"
@ -6638,6 +6683,11 @@ TEST_F(FormatTest, MergeHandlingInTheFaceOfPreprocessorDirectives) {
" return 1; \\\n"
" return 2;",
ShortMergedIf);
verifyFormat("#define A \\\n"
" if constexpr (aaaaaaa) \\\n"
" return 1; \\\n"
" return 2;",
ShortMergedIf);
}
TEST_F(FormatTest, FormatStarDependingOnContext) {
@ -8845,11 +8895,24 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
" }\n"
"}\n",
BreakBeforeBraceShortIfs);
verifyFormat("void f(bool b)\n"
"{\n"
" if constexpr (b)\n"
" {\n"
" return;\n"
" }\n"
"}\n",
BreakBeforeBraceShortIfs);
verifyFormat("void f(bool b)\n"
"{\n"
" if (b) return;\n"
"}\n",
BreakBeforeBraceShortIfs);
verifyFormat("void f(bool b)\n"
"{\n"
" if constexpr (b) return;\n"
"}\n",
BreakBeforeBraceShortIfs);
verifyFormat("void f(bool b)\n"
"{\n"
" while (b)\n"
@ -10098,6 +10161,11 @@ TEST_F(FormatTest, FormatsLambdas) {
" doo_dah();\n"
" })) {\n"
"}");
verifyFormat("if constexpr (blah_blah(whatever, whatever, [] {\n"
" doo_dah();\n"
" doo_dah();\n"
" })) {\n"
"}");
verifyFormat("auto lambda = []() {\n"
" int a = 2\n"
"#if A\n"