[clang] 0904e0b - [clang-format] Properly handle the C11 _Generic keyword.
Emilia Dreamer via cfe-commits
cfe-commits at lists.llvm.org
Tue Jan 10 20:02:36 PST 2023
Author: Emilia Dreamer
Date: 2023-01-11T06:00:16+02:00
New Revision: 0904e0bac8314249ee7c1b0658f1a1cc92ccd050
URL: https://github.com/llvm/llvm-project/commit/0904e0bac8314249ee7c1b0658f1a1cc92ccd050
DIFF: https://github.com/llvm/llvm-project/commit/0904e0bac8314249ee7c1b0658f1a1cc92ccd050.diff
LOG: [clang-format] Properly handle the C11 _Generic keyword.
This patch properly recognizes the generic selection expression
introduced in C11, by adding an additional token type for the colons
present in such expressions.
Previously, they would be recognized as
"inline ASM colons" purely by the fact that those are the last thing
checked for.
I tried to avoid adding an addition token type, but since colons by
default like having spaces around them, I chose to add a new type so
that no space is added after the type selector.
Currently, no aspect of the formatting of these expressions in able to
be configured, as I'm not sure what could even be configured here.
One notable thing is that association list is always formatted as
either entirely on one line, if it can fit, or with line breaks
after every comma in the expression (also after the controlling expr.)
This visually makes them more similar to switch statements when long,
matching the behaviour of the selection expression, being that of a sort
of switch on types, but also allows for terseness when only selecting
for a few things.
Fixes https://github.com/llvm/llvm-project/issues/18080
Reviewed By: HazardyKnusperkeks, owenpan, MyDeveloperDay
Differential Revision: https://reviews.llvm.org/D139211
Added:
Modified:
clang/lib/Format/ContinuationIndenter.cpp
clang/lib/Format/FormatToken.h
clang/lib/Format/TokenAnnotator.cpp
clang/unittests/Format/FormatTest.cpp
clang/unittests/Format/TokenAnnotatorTest.cpp
Removed:
################################################################################
diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 04244c146827..833b10e3a578 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -1538,6 +1538,12 @@ void ContinuationIndenter::moveStatePastFakeLParens(LineState &State,
std::max(State.Column, NewParenState.Indent), CurrentState.LastSpace);
}
+ // Special case for generic selection expressions, its comma-separated
+ // expressions are not aligned to the opening paren like regular calls, but
+ // rather continuation-indented relative to the _Generic keyword.
+ if (Previous && Previous->endsSequence(tok::l_paren, tok::kw__Generic))
+ NewParenState.Indent = CurrentState.LastSpace;
+
if (Previous &&
(Previous->getPrecedence() == prec::Assignment ||
Previous->isOneOf(tok::kw_return, TT_RequiresClause) ||
@@ -1684,8 +1690,12 @@ void ContinuationIndenter::moveStatePastScopeOpener(LineState &State,
(State.Line->Type != LT_ObjCDecl && Style.BinPackParameters) ||
(State.Line->Type == LT_ObjCDecl && ObjCBinPackProtocolList);
+ bool GenericSelection =
+ Current.getPreviousNonComment() &&
+ Current.getPreviousNonComment()->is(tok::kw__Generic);
+
AvoidBinPacking =
- (CurrentState.IsCSharpGenericTypeConstraint) ||
+ (CurrentState.IsCSharpGenericTypeConstraint) || GenericSelection ||
(Style.isJavaScript() && EndsInComma) ||
(State.Line->MustBeDeclaration && !BinPackDeclaration) ||
(!State.Line->MustBeDeclaration && !Style.BinPackArguments) ||
diff --git a/clang/lib/Format/FormatToken.h b/clang/lib/Format/FormatToken.h
index e8c6cd9a5d4b..6de9dfa383d5 100644
--- a/clang/lib/Format/FormatToken.h
+++ b/clang/lib/Format/FormatToken.h
@@ -70,6 +70,8 @@ namespace format {
TYPE(FunctionLBrace) \
TYPE(FunctionLikeOrFreestandingMacro) \
TYPE(FunctionTypeLParen) \
+ /* The colons as part of a C11 _Generic selection */ \
+ TYPE(GenericSelectionColon) \
/* The colon at the end of a goto label or a case label. Currently only used \
* for Verilog. */ \
TYPE(GotoLabelColon) \
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index c081b24d3372..8bd7bcf307db 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -322,6 +322,10 @@ class AnnotatingParser {
Contexts.back().IsExpression = false;
} else if (OpeningParen.is(TT_RequiresExpressionLParen)) {
Contexts.back().IsExpression = false;
+ } else if (OpeningParen.Previous &&
+ OpeningParen.Previous->is(tok::kw__Generic)) {
+ Contexts.back().ContextType = Context::C11GenericSelection;
+ Contexts.back().IsExpression = true;
} else if (Line.InPPDirective &&
(!OpeningParen.Previous ||
!OpeningParen.Previous->is(tok::identifier))) {
@@ -1027,6 +1031,8 @@ class AnnotatingParser {
}
} else if (Contexts.back().ColonIsForRangeExpr) {
Tok->setType(TT_RangeBasedForLoopColon);
+ } else if (Contexts.back().ContextType == Context::C11GenericSelection) {
+ Tok->setType(TT_GenericSelectionColon);
} else if (CurrentToken && CurrentToken->is(tok::numeric_constant)) {
Tok->setType(TT_BitFieldColon);
} else if (Contexts.size() == 1 &&
@@ -1626,6 +1632,8 @@ class AnnotatingParser {
StructArrayInitializer,
// Like in `static_cast<int>`.
TemplateArgument,
+ // C11 _Generic selection.
+ C11GenericSelection,
} ContextType = Unknown;
};
@@ -3254,7 +3262,8 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
return 100;
}
if (Left.is(tok::l_paren) && Left.Previous &&
- (Left.Previous->is(tok::kw_for) || Left.Previous->isIf())) {
+ (Left.Previous->isOneOf(tok::kw_for, tok::kw__Generic) ||
+ Left.Previous->isIf())) {
return 1000;
}
if (Left.is(tok::equal) && InFunctionDecl)
@@ -4163,6 +4172,8 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
return false;
if (Right.is(TT_CSharpNamedArgumentColon))
return false;
+ if (Right.is(TT_GenericSelectionColon))
+ return false;
if (Right.is(TT_BitFieldColon)) {
return Style.BitFieldColonSpacing == FormatStyle::BFCS_Both ||
Style.BitFieldColonSpacing == FormatStyle::BFCS_Before;
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index b39cae1ebe3f..5aa50cc6f9fd 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -23012,6 +23012,41 @@ TEST_F(FormatTest, AtomicQualifier) {
verifyFormat("x = (_Atomic( uint64_t ))&a;", Style);
}
+TEST_F(FormatTest, C11Generic) {
+ verifyFormat("_Generic(x, int: 1, default: 0)");
+ verifyFormat("#define cbrt(X) _Generic((X), float: cbrtf, default: cbrt)(X)");
+ verifyFormat("_Generic(x, const char *: 1, char *const: 16, int: 8);");
+ verifyFormat("_Generic(x, int: f1, const int: f2)();");
+ verifyFormat("_Generic(x, struct A: 1, void (*)(void): 2);");
+
+ verifyFormat("_Generic(x,\n"
+ " float: f,\n"
+ " default: d,\n"
+ " long double: ld,\n"
+ " float _Complex: fc,\n"
+ " double _Complex: dc,\n"
+ " long double _Complex: ldc)");
+
+ FormatStyle Style = getLLVMStyle();
+ Style.ColumnLimit = 40;
+ verifyFormat("#define LIMIT_MAX(T) \\\n"
+ " _Generic(((T)0), \\\n"
+ " unsigned int: UINT_MAX, \\\n"
+ " unsigned long: ULONG_MAX, \\\n"
+ " unsigned long long: ULLONG_MAX)",
+ Style);
+ verifyFormat("_Generic(x,\n"
+ " struct A: 1,\n"
+ " void (*)(void): 2);",
+ Style);
+
+ Style.ContinuationIndentWidth = 2;
+ verifyFormat("_Generic(x,\n"
+ " struct A: 1,\n"
+ " void (*)(void): 2);",
+ Style);
+}
+
TEST_F(FormatTest, AmbersandInLamda) {
// Test case reported in https://bugs.llvm.org/show_bug.cgi?id=41899
FormatStyle AlignStyle = getLLVMStyle();
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 66903f1fe898..3ed6521d48c1 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -1152,6 +1152,14 @@ TEST_F(TokenAnnotatorTest, UnderstandsFunctionDeclarationNames) {
EXPECT_TOKEN(Tokens[1], tok::identifier, TT_FunctionDeclarationName);
}
+TEST_F(TokenAnnotatorTest, UnderstandsC11GenericSelection) {
+ auto Tokens = annotate("_Generic(x, int: 1, default: 0)");
+ ASSERT_EQ(Tokens.size(), 13u) << Tokens;
+ EXPECT_TOKEN(Tokens[0], tok::kw__Generic, TT_Unknown);
+ EXPECT_TOKEN(Tokens[5], tok::colon, TT_GenericSelectionColon);
+ EXPECT_TOKEN(Tokens[9], tok::colon, TT_GenericSelectionColon);
+}
+
TEST_F(TokenAnnotatorTest, UnderstandsVerilogOperators) {
auto Annotate = [this](llvm::StringRef Code) {
return annotate(Code, getLLVMStyle(FormatStyle::LK_Verilog));
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