r298574 - Fix issues in clang-format's AlignConsecutive modes.
Hans Wennborg via cfe-commits
cfe-commits at lists.llvm.org
Thu Aug 24 11:12:34 PDT 2017
For reference, this was reviewed in https://reviews.llvm.org/D21279
(Please always include review links in the future.)
On Wed, Mar 22, 2017 at 7:51 PM, Nikola Smiljanic via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
> Author: nikola
> Date: Wed Mar 22 21:51:25 2017
> New Revision: 298574
>
> URL: http://llvm.org/viewvc/llvm-project?rev=298574&view=rev
> Log:
> Fix issues in clang-format's AlignConsecutive modes.
>
> Patch by Ben Harper.
>
> Modified:
> cfe/trunk/lib/Format/WhitespaceManager.cpp
> cfe/trunk/lib/Format/WhitespaceManager.h
> cfe/trunk/unittests/Format/FormatTest.cpp
>
> Modified: cfe/trunk/lib/Format/WhitespaceManager.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/WhitespaceManager.cpp?rev=298574&r1=298573&r2=298574&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Format/WhitespaceManager.cpp (original)
> +++ cfe/trunk/lib/Format/WhitespaceManager.cpp Wed Mar 22 21:51:25 2017
> @@ -50,9 +50,9 @@ void WhitespaceManager::replaceWhitespac
> if (Tok.Finalized)
> return;
> Tok.Decision = (Newlines > 0) ? FD_Break : FD_Continue;
> - Changes.push_back(Change(Tok, /*CreateReplacement=*/true,
> - Tok.WhitespaceRange, Spaces, StartOfTokenColumn,
> - Newlines, "", "", InPPDirective && !Tok.IsFirst,
> + Changes.push_back(Change(Tok, /*CreateReplacement=*/true, Tok.WhitespaceRange,
> + Spaces, StartOfTokenColumn, Newlines, "", "",
> + InPPDirective && !Tok.IsFirst,
> /*IsInsideToken=*/false));
> }
>
> @@ -192,21 +192,56 @@ AlignTokenSequence(unsigned Start, unsig
> SmallVector<WhitespaceManager::Change, 16> &Changes) {
> bool FoundMatchOnLine = false;
> int Shift = 0;
> +
> + // ScopeStack keeps track of the current scope depth. It contains indices of
> + // the first token on each scope.
> + // We only run the "Matches" function on tokens from the outer-most scope.
> + // However, we do need to pay special attention to one class of tokens
> + // that are not in the outer-most scope, and that is function parameters
> + // which are split across multiple lines, as illustrated by this example:
> + // double a(int x);
> + // int b(int y,
> + // double z);
> + // In the above example, we need to take special care to ensure that
> + // 'double z' is indented along with it's owning function 'b'.
> + SmallVector<unsigned, 16> ScopeStack;
> +
> for (unsigned i = Start; i != End; ++i) {
> - if (Changes[i].NewlinesBefore > 0) {
> - FoundMatchOnLine = false;
> + if (ScopeStack.size() != 0 &&
> + Changes[i].nestingAndIndentLevel() <
> + Changes[ScopeStack.back()].nestingAndIndentLevel())
> + ScopeStack.pop_back();
> +
> + if (i != Start && Changes[i].nestingAndIndentLevel() >
> + Changes[i - 1].nestingAndIndentLevel())
> + ScopeStack.push_back(i);
> +
> + bool InsideNestedScope = ScopeStack.size() != 0;
> +
> + if (Changes[i].NewlinesBefore > 0 && !InsideNestedScope) {
> Shift = 0;
> + FoundMatchOnLine = false;
> }
>
> // If this is the first matching token to be aligned, remember by how many
> // spaces it has to be shifted, so the rest of the changes on the line are
> // shifted by the same amount
> - if (!FoundMatchOnLine && Matches(Changes[i])) {
> + if (!FoundMatchOnLine && !InsideNestedScope && Matches(Changes[i])) {
> FoundMatchOnLine = true;
> Shift = Column - Changes[i].StartOfTokenColumn;
> Changes[i].Spaces += Shift;
> }
>
> + // This is for function parameters that are split across multiple lines,
> + // as mentioned in the ScopeStack comment.
> + if (InsideNestedScope && Changes[i].NewlinesBefore > 0) {
> + unsigned ScopeStart = ScopeStack.back();
> + if (Changes[ScopeStart - 1].Tok->is(TT_FunctionDeclarationName) ||
> + (ScopeStart > Start + 1 &&
> + Changes[ScopeStart - 2].Tok->is(TT_FunctionDeclarationName)))
> + Changes[i].Spaces += Shift;
> + }
> +
> assert(Shift >= 0);
> Changes[i].StartOfTokenColumn += Shift;
> if (i + 1 != Changes.size())
> @@ -214,15 +249,37 @@ AlignTokenSequence(unsigned Start, unsig
> }
> }
>
> -// Walk through all of the changes and find sequences of matching tokens to
> -// align. To do so, keep track of the lines and whether or not a matching token
> -// was found on a line. If a matching token is found, extend the current
> -// sequence. If the current line cannot be part of a sequence, e.g. because
> -// there is an empty line before it or it contains only non-matching tokens,
> -// finalize the previous sequence.
> +// Walk through a subset of the changes, starting at StartAt, and find
> +// sequences of matching tokens to align. To do so, keep track of the lines and
> +// whether or not a matching token was found on a line. If a matching token is
> +// found, extend the current sequence. If the current line cannot be part of a
> +// sequence, e.g. because there is an empty line before it or it contains only
> +// non-matching tokens, finalize the previous sequence.
> +// The value returned is the token on which we stopped, either because we
> +// exhausted all items inside Changes, or because we hit a scope level higher
> +// than our initial scope.
> +// This function is recursive. Each invocation processes only the scope level
> +// equal to the initial level, which is the level of Changes[StartAt].
> +// If we encounter a scope level greater than the initial level, then we call
> +// ourselves recursively, thereby avoiding the pollution of the current state
> +// with the alignment requirements of the nested sub-level. This recursive
> +// behavior is necessary for aligning function prototypes that have one or more
> +// arguments.
> +// If this function encounters a scope level less than the initial level,
> +// it returns the current position.
> +// There is a non-obvious subtlety in the recursive behavior: Even though we
> +// defer processing of nested levels to recursive invocations of this
> +// function, when it comes time to align a sequence of tokens, we run the
> +// alignment on the entire sequence, including the nested levels.
> +// When doing so, most of the nested tokens are skipped, because their
> +// alignment was already handled by the recursive invocations of this function.
> +// However, the special exception is that we do NOT skip function parameters
> +// that are split across multiple lines. See the test case in FormatTest.cpp
> +// that mentions "split function parameter alignment" for an example of this.
> template <typename F>
> -static void AlignTokens(const FormatStyle &Style, F &&Matches,
> - SmallVector<WhitespaceManager::Change, 16> &Changes) {
> +static unsigned AlignTokens(const FormatStyle &Style, F &&Matches,
> + SmallVector<WhitespaceManager::Change, 16> &Changes,
> + unsigned StartAt) {
> unsigned MinColumn = 0;
> unsigned MaxColumn = UINT_MAX;
>
> @@ -230,14 +287,11 @@ static void AlignTokens(const FormatStyl
> unsigned StartOfSequence = 0;
> unsigned EndOfSequence = 0;
>
> - // Keep track of the nesting level of matching tokens, i.e. the number of
> - // surrounding (), [], or {}. We will only align a sequence of matching
> - // token that share the same scope depth.
> - //
> - // FIXME: This could use FormatToken::NestingLevel information, but there is
> - // an outstanding issue wrt the brace scopes.
> - unsigned NestingLevelOfLastMatch = 0;
> - unsigned NestingLevel = 0;
> + // Measure the scope level (i.e. depth of (), [], {}) of the first token, and
> + // abort when we hit any token in a higher scope than the starting one.
> + auto NestingAndIndentLevel = StartAt < Changes.size()
> + ? Changes[StartAt].nestingAndIndentLevel()
> + : std::pair<unsigned, unsigned>(0, 0);
>
> // Keep track of the number of commas before the matching tokens, we will only
> // align a sequence of matching tokens if they are preceded by the same number
> @@ -265,7 +319,11 @@ static void AlignTokens(const FormatStyl
> EndOfSequence = 0;
> };
>
> - for (unsigned i = 0, e = Changes.size(); i != e; ++i) {
> + unsigned i = StartAt;
> + for (unsigned e = Changes.size(); i != e; ++i) {
> + if (Changes[i].nestingAndIndentLevel() < NestingAndIndentLevel)
> + break;
> +
> if (Changes[i].NewlinesBefore != 0) {
> CommasBeforeMatch = 0;
> EndOfSequence = i;
> @@ -279,29 +337,22 @@ static void AlignTokens(const FormatStyl
>
> if (Changes[i].Tok->is(tok::comma)) {
> ++CommasBeforeMatch;
> - } else if (Changes[i].Tok->isOneOf(tok::r_brace, tok::r_paren,
> - tok::r_square)) {
> - --NestingLevel;
> - } else if (Changes[i].Tok->isOneOf(tok::l_brace, tok::l_paren,
> - tok::l_square)) {
> - // We want sequences to skip over child scopes if possible, but not the
> - // other way around.
> - NestingLevelOfLastMatch = std::min(NestingLevelOfLastMatch, NestingLevel);
> - ++NestingLevel;
> + } else if (Changes[i].nestingAndIndentLevel() > NestingAndIndentLevel) {
> + // Call AlignTokens recursively, skipping over this scope block.
> + unsigned StoppedAt = AlignTokens(Style, Matches, Changes, i);
> + i = StoppedAt - 1;
> + continue;
> }
>
> if (!Matches(Changes[i]))
> continue;
>
> // If there is more than one matching token per line, or if the number of
> - // preceding commas, or the scope depth, do not match anymore, end the
> - // sequence.
> - if (FoundMatchOnLine || CommasBeforeMatch != CommasBeforeLastMatch ||
> - NestingLevel != NestingLevelOfLastMatch)
> + // preceding commas, do not match anymore, end the sequence.
> + if (FoundMatchOnLine || CommasBeforeMatch != CommasBeforeLastMatch)
> AlignCurrentSequence();
>
> CommasBeforeLastMatch = CommasBeforeMatch;
> - NestingLevelOfLastMatch = NestingLevel;
> FoundMatchOnLine = true;
>
> if (StartOfSequence == 0)
> @@ -324,8 +375,9 @@ static void AlignTokens(const FormatStyl
> MaxColumn = std::min(MaxColumn, ChangeMaxColumn);
> }
>
> - EndOfSequence = Changes.size();
> + EndOfSequence = i;
> AlignCurrentSequence();
> + return i;
> }
>
> void WhitespaceManager::alignConsecutiveAssignments() {
> @@ -344,7 +396,7 @@ void WhitespaceManager::alignConsecutive
>
> return C.Tok->is(tok::equal);
> },
> - Changes);
> + Changes, /*StartAt=*/0);
> }
>
> void WhitespaceManager::alignConsecutiveDeclarations() {
> @@ -357,13 +409,15 @@ void WhitespaceManager::alignConsecutive
> // const char* const* v1;
> // float const* v2;
> // SomeVeryLongType const& v3;
> -
> AlignTokens(Style,
> [](Change const &C) {
> - return C.Tok->isOneOf(TT_StartOfName,
> - TT_FunctionDeclarationName);
> + // tok::kw_operator is necessary for aligning operator overload
> + // definitions.
> + return C.Tok->is(TT_StartOfName) ||
> + C.Tok->is(TT_FunctionDeclarationName) ||
> + C.Tok->is(tok::kw_operator);
> },
> - Changes);
> + Changes, /*StartAt=*/0);
> }
>
> void WhitespaceManager::alignTrailingComments() {
>
> Modified: cfe/trunk/lib/Format/WhitespaceManager.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/WhitespaceManager.h?rev=298574&r1=298573&r2=298574&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Format/WhitespaceManager.h (original)
> +++ cfe/trunk/lib/Format/WhitespaceManager.h Wed Mar 22 21:51:25 2017
> @@ -149,6 +149,14 @@ public:
> // the alignment process.
> const Change *StartOfBlockComment;
> int IndentationOffset;
> +
> + // A combination of nesting level and indent level, which are used in
> + // tandem to compute lexical scope, for the purposes of deciding
> + // when to stop consecutive alignment runs.
> + std::pair<unsigned, unsigned>
> + nestingAndIndentLevel() const {
> + return std::make_pair(Tok->NestingLevel, Tok->IndentLevel);
> + }
> };
>
> private:
>
> Modified: cfe/trunk/unittests/Format/FormatTest.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Format/FormatTest.cpp?rev=298574&r1=298573&r2=298574&view=diff
> ==============================================================================
> --- cfe/trunk/unittests/Format/FormatTest.cpp (original)
> +++ cfe/trunk/unittests/Format/FormatTest.cpp Wed Mar 22 21:51:25 2017
> @@ -7672,12 +7672,11 @@ TEST_F(FormatTest, AlignConsecutiveAssig
> "};",
> Alignment);
>
> - // FIXME: Should align all three assignments
> verifyFormat(
> "int i = 1;\n"
> "SomeType a = SomeFunction(looooooooooooooooooooooongParameterA,\n"
> " loooooooooooooooooooooongParameterB);\n"
> - "int j = 2;",
> + "int j = 2;",
> Alignment);
>
> verifyFormat("template <typename T, typename T_0 = very_long_type_name_0,\n"
> @@ -7692,6 +7691,13 @@ TEST_F(FormatTest, AlignConsecutiveAssig
> verifyFormat("int aa = ((1 > 2) ? 3 : 4);\n"
> "float b[1][] = {{3.f}};\n",
> Alignment);
> + verifyFormat("for (int i = 0; i < 1; i++)\n"
> + " int x = 1;\n",
> + Alignment);
> + verifyFormat("for (i = 0; i < 1; i++)\n"
> + " x = 1;\n"
> + "y = 1;\n",
> + Alignment);
> }
>
> TEST_F(FormatTest, AlignConsecutiveDeclarations) {
> @@ -7759,7 +7765,57 @@ TEST_F(FormatTest, AlignConsecutiveDecla
> "unsigned oneTwoThree = 123;\n"
> "int oneTwo = 12;",
> Alignment));
> + // Function prototype alignment
> + verifyFormat("int a();\n"
> + "double b();",
> + Alignment);
> + verifyFormat("int a(int x);\n"
> + "double b();",
> + Alignment);
> + unsigned OldColumnLimit = Alignment.ColumnLimit;
> + // We need to set ColumnLimit to zero, in order to stress nested alignments,
> + // otherwise the function parameters will be re-flowed onto a single line.
> + Alignment.ColumnLimit = 0;
> + EXPECT_EQ("int a(int x,\n"
> + " float y);\n"
> + "double b(int x,\n"
> + " double y);",
> + format("int a(int x,\n"
> + " float y);\n"
> + "double b(int x,\n"
> + " double y);",
> + Alignment));
> + // This ensures that function parameters of function declarations are
> + // correctly indented when their owning functions are indented.
> + // The failure case here is for 'double y' to not be indented enough.
> + EXPECT_EQ("double a(int x);\n"
> + "int b(int y,\n"
> + " double z);",
> + format("double a(int x);\n"
> + "int b(int y,\n"
> + " double z);",
> + Alignment));
> + // Set ColumnLimit low so that we induce wrapping immediately after
> + // the function name and opening paren.
> + Alignment.ColumnLimit = 13;
> + verifyFormat("int function(\n"
> + " int x,\n"
> + " bool y);",
> + Alignment);
> + Alignment.ColumnLimit = OldColumnLimit;
> + // Ensure function pointers don't screw up recursive alignment
> + verifyFormat("int a(int x, void (*fp)(int y));\n"
> + "double b();",
> + Alignment);
> Alignment.AlignConsecutiveAssignments = true;
> + // Ensure recursive alignment is broken by function braces, so that the
> + // "a = 1" does not align with subsequent assignments inside the function
> + // body.
> + verifyFormat("int func(int a = 1) {\n"
> + " int b = 2;\n"
> + " int cc = 3;\n"
> + "}",
> + Alignment);
> verifyFormat("float something = 2000;\n"
> "double another = 911;\n"
> "int i = 1, j = 10;\n"
> @@ -7769,6 +7825,28 @@ TEST_F(FormatTest, AlignConsecutiveDecla
> verifyFormat("int oneTwoThree = {0}; // comment\n"
> "unsigned oneTwo = 0; // comment",
> Alignment);
> + // Make sure that scope is correctly tracked, in the absence of braces
> + verifyFormat("for (int i = 0; i < n; i++)\n"
> + " j = i;\n"
> + "double x = 1;\n",
> + Alignment);
> + verifyFormat("if (int i = 0)\n"
> + " j = i;\n"
> + "double x = 1;\n",
> + Alignment);
> + // Ensure operator[] and operator() are comprehended
> + verifyFormat("struct test {\n"
> + " long long int foo();\n"
> + " int operator[](int a);\n"
> + " double bar();\n"
> + "};\n",
> + Alignment);
> + verifyFormat("struct test {\n"
> + " long long int foo();\n"
> + " int operator()(int a);\n"
> + " double bar();\n"
> + "};\n",
> + Alignment);
> EXPECT_EQ("void SomeFunction(int parameter = 0) {\n"
> " int const i = 1;\n"
> " int * j = 2;\n"
> @@ -7870,17 +7948,16 @@ TEST_F(FormatTest, AlignConsecutiveDecla
> Alignment);
> Alignment.AlignConsecutiveAssignments = false;
>
> - // FIXME: Should align all three declarations
> verifyFormat(
> "int i = 1;\n"
> "SomeType a = SomeFunction(looooooooooooooooooooooongParameterA,\n"
> " loooooooooooooooooooooongParameterB);\n"
> - "int j = 2;",
> + "int j = 2;",
> Alignment);
>
> // Test interactions with ColumnLimit and AlignConsecutiveAssignments:
> // We expect declarations and assignments to align, as long as it doesn't
> - // exceed the column limit, starting a new alignemnt sequence whenever it
> + // exceed the column limit, starting a new alignment sequence whenever it
> // happens.
> Alignment.AlignConsecutiveAssignments = true;
> Alignment.ColumnLimit = 30;
>
>
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