Merge pull request swiftlang#31627 from compnerd/unreachable-coverage

sprinkle `llvm_unreachable` for covered switches (NFC)

Author: compnerd

include/swift/AST/Decl.h

@@ -7187,6 +7187,7 @@ class OperatorDecl : public Decl {
     case DeclKind::PostfixOperator:
       return OperatorFixity::Postfix;
     }
+    llvm_unreachable("inavlid decl kind");
   }
 
   SourceLoc getOperatorLoc() const { return OperatorLoc; }

include/swift/AST/EvaluatorDependencies.h

@@ -94,6 +94,7 @@ inline DependencyScope getScopeForAccessLevel(AccessLevel l) {
   case AccessLevel::Open:
     return DependencyScope::Cascading;
   }
+  llvm_unreachable("invalid access level kind");
 }
 
 // A \c DependencySource is currently defined to be a parent source file and
@@ -258,6 +259,7 @@ struct DependencyCollector {
     case Mode::ExperimentalPrivateDependencies:
       return false;
     }
+    llvm_unreachable("invalid mode");
   }
 };
 } // end namespace evaluator

include/swift/AST/Stmt.h

@@ -1015,6 +1015,7 @@ class CaseStmt final
       return SourceRange(getLoc(), getLoc());
     }
     }
+    llvm_unreachable("invalid parent kind");
   }
 
   bool isDefault() { return getCaseLabelItems()[0].isDefault(); }

lib/AST/ASTDemangler.cpp

@@ -452,6 +452,7 @@ getParameterDifferentiability(ImplParameterDifferentiability diffKind) {
   case ImplParameterDifferentiability::NotDifferentiable:
     return SILParameterDifferentiability::NotDifferentiable;
   }
+  llvm_unreachable("unknown differentiability kind");
 }
 
 static ResultConvention getResultConvention(ImplResultConvention conv) {

lib/AST/AutoDiff.cpp

@@ -62,6 +62,7 @@ NormalDifferentiableFunctionTypeComponent::getAsDerivativeFunctionKind() const {
   case VJP:
     return {AutoDiffDerivativeFunctionKind::VJP};
   }
+  llvm_unreachable("invalid derivative kind");
 }
 
 LinearDifferentiableFunctionTypeComponent::
@@ -93,6 +94,7 @@ DifferentiabilityWitnessFunctionKind::getAsDerivativeFunctionKind() const {
   case Transpose:
     return None;
   }
+  llvm_unreachable("invalid derivative kind");
 }
 
 void SILAutoDiffIndices::print(llvm::raw_ostream &s) const {
@@ -375,6 +377,7 @@ Type TangentSpace::getType() const {
   case Kind::Tuple:
     return value.tupleType;
   }
+  llvm_unreachable("invalid tangent space kind");
 }
 
 CanType TangentSpace::getCanonicalType() const {

lib/AST/ClangTypeConverter.cpp

@@ -155,6 +155,7 @@ const clang::Type *ClangTypeConverter::getFunctionType(
   case AnyFunctionType::Representation::Thin:
     llvm_unreachable("Expected a C-compatible representation.");
   }
+  llvm_unreachable("invalid representation");
 }
 
 clang::QualType ClangTypeConverter::convertMemberType(NominalTypeDecl *DC,

lib/AST/Decl.cpp

@@ -645,6 +645,7 @@ static_assert(sizeof(checkSourceLocType(&ID##Decl::getLoc)) == 2, \
   case FileUnitKind::DWARFModule:
     return SourceLoc();
   }
+  llvm_unreachable("invalid file kind");
 }
 
 Expr *AbstractFunctionDecl::getSingleExpressionBody() const {
@@ -6297,6 +6298,7 @@ bool ParamDecl::hasCallerSideDefaultExpr() const {
   case DefaultArgumentKind::EmptyDictionary:
     return true;
   }
+  llvm_unreachable("invalid default argument kind");
 }
 
 Expr *ParamDecl::getTypeCheckedDefaultExpr() const {

lib/AST/ModuleDependencies.cpp

@@ -106,6 +106,7 @@ ModuleDependenciesCache::getDependenciesMap(ModuleDependenciesKind kind) {
   case ModuleDependenciesKind::Clang:
     return ClangModuleDependencies;
   }
+  llvm_unreachable("invalid dependency kind");
 }
 
 const llvm::StringMap<ModuleDependencies> &
@@ -117,6 +118,7 @@ ModuleDependenciesCache::getDependenciesMap(ModuleDependenciesKind kind) const {
   case ModuleDependenciesKind::Clang:
     return ClangModuleDependencies;
   }
+  llvm_unreachable("invalid dependency kind");
 }
 
 bool ModuleDependenciesCache::hasDependencies(

lib/AST/Type.cpp

@@ -2969,6 +2969,7 @@ static bool canSubstituteTypeInto(Type ty, const DeclContext *dc,
 
     return typeDecl->getEffectiveAccess() > AccessLevel::Internal;
   }
+  llvm_unreachable("invalid subsitution kind");
 }
 
 Type ReplaceOpaqueTypesWithUnderlyingTypes::

lib/Driver/Compilation.cpp

@@ -1079,6 +1079,7 @@ namespace driver {
                      forRanges, "file is up-to-date and output exists");
         return false;
       }
+      llvm_unreachable("invalid job condition");
     }
 
     bool isCascadingJobAccordingToCondition(
@@ -1092,6 +1093,7 @@ namespace driver {
       case Job::Condition::CheckDependencies:
         return false;
       }
+      llvm_unreachable("invalid job condition");
     }
 
     void forEachOutOfDateExternalDependency(