[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

5 files changed, 10 insertions, 5 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/IdenticalExprChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/IdenticalExprChecker.cpp
index 0c3bff5b63b..cf57b8dca06 100644
--- a/clang/lib/StaticAnalyzer/Checkers/IdenticalExprChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/IdenticalExprChecker.cpp
@@ -255,7 +255,10 @@ void FindIdenticalExprVisitor::checkComparisonOp(const BinaryOperator *B) {
     PathDiagnosticLocation ELoc =
         PathDiagnosticLocation::createOperatorLoc(B, BR.getSourceManager());
     StringRef Message;
-    if (((Op == BO_EQ) || (Op == BO_LE) || (Op == BO_GE)))
+    if (Op == BO_Cmp)
+      Message = "comparison of identical expressions always evaluates to "
+                "'equal'";
+    else if (((Op == BO_EQ) || (Op == BO_LE) || (Op == BO_GE)))
       Message = "comparison of identical expressions always evaluates to true";
     else
       Message = "comparison of identical expressions always evaluates to false";
diff --git a/clang/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp b/clang/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
index f651596006b..7304d789431 100644
--- a/clang/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
+++ b/clang/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
@@ -1541,7 +1541,7 @@ ConditionBRVisitor::VisitTrueTest(const Expr *Cond, const BinaryOperator *BExpr,
   // For non-assignment operations, we require that we can understand
   // both the LHS and RHS.
   if (LhsString.empty() || RhsString.empty() ||
-      !BinaryOperator::isComparisonOp(Op))
+      !BinaryOperator::isComparisonOp(Op) || Op == BO_Cmp)
     return nullptr;
 
   // Should we invert the strings if the LHS is not a variable name?
diff --git a/clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp b/clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
index 6a4c4d11585..5a4031c0b4a 100644
--- a/clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
@@ -396,7 +396,9 @@ bool RangeConstraintManager::canReasonAbout(SVal X) const {
     }
 
     if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(SE)) {
-      if (BinaryOperator::isComparisonOp(SSE->getOpcode())) {
+      // FIXME: Handle <=> here.
+      if (BinaryOperator::isEqualityOp(SSE->getOpcode()) ||
+          BinaryOperator::isRelationalOp(SSE->getOpcode())) {
         // We handle Loc <> Loc comparisons, but not (yet) NonLoc <> NonLoc.
         if (Loc::isLocType(SSE->getLHS()->getType())) {
           assert(Loc::isLocType(SSE->getRHS()->getType()));
diff --git a/clang/lib/StaticAnalyzer/Core/RangedConstraintManager.cpp b/clang/lib/StaticAnalyzer/Core/RangedConstraintManager.cpp
index 1304116f497..55ff15806ef 100644
--- a/clang/lib/StaticAnalyzer/Core/RangedConstraintManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/RangedConstraintManager.cpp
@@ -33,7 +33,7 @@ ProgramStateRef RangedConstraintManager::assumeSym(ProgramStateRef State,
     // We can only simplify expressions whose RHS is an integer.
 
     BinaryOperator::Opcode op = SIE->getOpcode();
-    if (BinaryOperator::isComparisonOp(op)) {
+    if (BinaryOperator::isComparisonOp(op) && op != BO_Cmp) {
       if (!Assumption)
         op = BinaryOperator::negateComparisonOp(op);
 
diff --git a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
index a5b5744c3fb..94d29d5a6ba 100644
--- a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -679,7 +679,7 @@ SVal SimpleSValBuilder::evalBinOpLL(ProgramStateRef state,
     if (SymbolRef rSym = rhs.getAsLocSymbol()) {
       // We can only build expressions with symbols on the left,
       // so we need a reversible operator.
-      if (!BinaryOperator::isComparisonOp(op))
+      if (!BinaryOperator::isComparisonOp(op) || op == BO_Cmp)
         return UnknownVal();
 
       const llvm::APSInt &lVal = lhs.castAs<loc::ConcreteInt>().getValue();