[c++20] P0515R3: Parsing support and basic AST construction for operator <=>.

Adding the new enumerator forced a bunch more changes into this patch than I
would have liked. The -Wtautological-compare warning was extended to properly
check the new comparison operator, clang-format needed updating because it uses
precedence levels as weights for determining where to break lines (and several
operators increased their precedence levels with this change), thread-safety
analysis needed changes to build its own IL properly for the new operator.

All "real" semantic checking for this operator has been deferred to a future
patch. For now, we use the relational comparison rules and arbitrarily give
the builtin form of the operator a return type of 'void'.

llvm-svn: 320707

3 files changed, 6 insertions, 3 deletions

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index e022a3a8c77..a3d38b244c5 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -323,7 +323,8 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
     // We need special cases for ">>" which we have split into two ">" while
     // lexing in order to make template parsing easier.
     bool IsComparison = (Previous.getPrecedence() == prec::Relational ||
-                         Previous.getPrecedence() == prec::Equality) &&
+                         Previous.getPrecedence() == prec::Equality ||
+                         Previous.getPrecedence() == prec::Spaceship) &&
                         Previous.Previous &&
                         Previous.Previous->isNot(TT_BinaryOperator); // For >>.
     bool LHSIsBinaryExpr =
@@ -536,7 +537,8 @@ void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
        (P->is(TT_ConditionalExpr) && P->is(tok::colon))) &&
       !P->isOneOf(TT_OverloadedOperator, TT_CtorInitializerComma) &&
       P->getPrecedence() != prec::Assignment &&
-      P->getPrecedence() != prec::Relational) {
+      P->getPrecedence() != prec::Relational &&
+      P->getPrecedence() != prec::Spaceship) {
     bool BreakBeforeOperator =
         P->MustBreakBefore || P->is(tok::lessless) ||
         (P->is(TT_BinaryOperator) &&
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 38e8163d3fe..217c6729ee3 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -2074,6 +2074,7 @@ LangOptions getFormattingLangOpts(const FormatStyle &Style) {
   LangOpts.CPlusPlus11 = Style.Standard == FormatStyle::LS_Cpp03 ? 0 : 1;
   LangOpts.CPlusPlus14 = Style.Standard == FormatStyle::LS_Cpp03 ? 0 : 1;
   LangOpts.CPlusPlus17 = Style.Standard == FormatStyle::LS_Cpp03 ? 0 : 1;
+  LangOpts.CPlusPlus2a = Style.Standard == FormatStyle::LS_Cpp03 ? 0 : 1;
   LangOpts.LineComment = 1;
   bool AlternativeOperators = Style.isCpp();
   LangOpts.CXXOperatorNames = AlternativeOperators ? 1 : 0;
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index c394fa03b26..298c72b002f 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2153,7 +2153,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
   if (Left.isOneOf(tok::plus, tok::comma) && Left.Previous &&
       Left.Previous->isLabelString() &&
       (Left.NextOperator || Left.OperatorIndex != 0))
-    return 45;
+    return 50;
   if (Right.is(tok::plus) && Left.isLabelString() &&
       (Right.NextOperator || Right.OperatorIndex != 0))
     return 25;