[CFG] [analyzer] Add C++17-specific ctor-initializer construction contexts.

CXXCtorInitializer-based constructors are also affected by the C++17 mandatory
copy elision, like variable constructors and return value constructors.
Extend r328248 to support those.

Differential Revision: https://reviews.llvm.org/D44763

llvm-svn: 328255

3 files changed, 29 insertions, 10 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index 77eb1d37a40..77770c56f31 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -4911,10 +4911,18 @@ static void print_construction_context(raw_ostream &OS,
                                        const ConstructionContext *CC) {
   const Stmt *S1 = nullptr, *S2 = nullptr;
   switch (CC->getKind()) {
-  case ConstructionContext::ConstructorInitializerKind: {
+  case ConstructionContext::SimpleConstructorInitializerKind: {
     OS << ", ";
-    const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);
-    print_initializer(OS, Helper, ICC->getCXXCtorInitializer());
+    const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
+    print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
+    break;
+  }
+  case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind: {
+    OS << ", ";
+    const auto *CICC =
+        cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
+    print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
+    S2 = CICC->getCXXBindTemporaryExpr();
     break;
   }
   case ConstructionContext::SimpleVariableKind: {
diff --git a/clang/lib/Analysis/ConstructionContext.cpp b/clang/lib/Analysis/ConstructionContext.cpp
index 31657df259c..ad0dbd2bb11 100644
--- a/clang/lib/Analysis/ConstructionContext.cpp
+++ b/clang/lib/Analysis/ConstructionContext.cpp
@@ -62,21 +62,31 @@ const ConstructionContext *ConstructionContext::createFromLayers(
       // lifetime extension on the parent layer.
       if (const ConstructionContextLayer *ParentLayer = TopLayer->getParent()) {
         assert(ParentLayer->isLast());
+        // C++17 *requires* elision of the constructor at the return site
+        // and at variable/member initialization site, while previous standards
+        // were allowing an optional elidable constructor.
+        // This is the C++17 copy-elided construction into a ctor initializer.
+        if (const CXXCtorInitializer *I = ParentLayer->getTriggerInit()) {
+          return create<
+              CXX17ElidedCopyConstructorInitializerConstructionContext>(C,
+                                                                        I, BTE);
+        }
+        assert(ParentLayer->getTriggerStmt() &&
+               "Non-statement-based layers have been handled above!");
+        // This is the normal, non-C++17 case: a temporary object which has
+        // both destruction and materialization info attached to it in the AST.
         if ((MTE = dyn_cast<MaterializeTemporaryExpr>(
                  ParentLayer->getTriggerStmt()))) {
-          // A temporary object which has both destruction and
-          // materialization info.
           return create<TemporaryObjectConstructionContext>(C, BTE, MTE);
         }
-        // C++17 *requires* elision of the constructor at the return site
-        // and at variable initialization site, while previous standards
-        // were allowing an optional elidable constructor.
+        // This is C++17 copy-elided construction into return statement.
         if (auto *RS = dyn_cast<ReturnStmt>(ParentLayer->getTriggerStmt())) {
           assert(!RS->getRetValue()->getType().getCanonicalType()
                     ->getAsCXXRecordDecl()->hasTrivialDestructor());
           return create<CXX17ElidedCopyReturnedValueConstructionContext>(C,
                                                                        RS, BTE);
         }
+        // This is C++17 copy-elided construction into a simple variable.
         if (auto *DS = dyn_cast<DeclStmt>(ParentLayer->getTriggerStmt())) {
           assert(!cast<VarDecl>(DS->getSingleDecl())->getType()
                       .getCanonicalType()->getAsCXXRecordDecl()
@@ -104,7 +114,7 @@ const ConstructionContext *ConstructionContext::createFromLayers(
     llvm_unreachable("Unexpected construction context with statement!");
   } else if (const CXXCtorInitializer *I = TopLayer->getTriggerInit()) {
     assert(TopLayer->isLast());
-    return create<ConstructorInitializerConstructionContext>(C, I);
+    return create<SimpleConstructorInitializerConstructionContext>(C, I);
   }
   llvm_unreachable("Unexpected construction context!");
 }
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
index ea1d1d30c39..3bea9465706 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
@@ -134,7 +134,7 @@ ExprEngine::getRegionForConstructedObject(const CXXConstructExpr *CE,
           makeZeroElementRegion(State, LValue, Ty, CallOpts.IsArrayCtorOrDtor);
       return LValue.getAsRegion();
     }
-    case ConstructionContext::ConstructorInitializerKind: {
+    case ConstructionContext::SimpleConstructorInitializerKind: {
       const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);
       const auto *Init = ICC->getCXXCtorInitializer();
       assert(Init->isAnyMemberInitializer());
@@ -217,6 +217,7 @@ ExprEngine::getRegionForConstructedObject(const CXXConstructExpr *CE,
     }
     case ConstructionContext::CXX17ElidedCopyVariableKind:
     case ConstructionContext::CXX17ElidedCopyReturnedValueKind:
+    case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind:
       // Not implemented yet.
       break;
     }