[clang] cde8d2f - Fix miscompile when performing template instantiation of non-dependent

[Richard Smith via cfe-commits]

Author: Richard Smith
Date: 2021-02-03T23:38:02-08:00
New Revision: cde8d2fddbff55cae520d90f47f6faf124d3f953

URL: https://github.com/llvm/llvm-project/commit/cde8d2fddbff55cae520d90f47f6faf124d3f953
DIFF: https://github.com/llvm/llvm-project/commit/cde8d2fddbff55cae520d90f47f6faf124d3f953.diff

LOG: Fix miscompile when performing template instantiation of non-dependent
doubly-nested implicit CXXConstructExprs.

Ensure that we transform the parameter initializer using
TransformInitializer rather than TransformExpr so that we properly strip
down and rebuild the initialization, including any necessary
CXXBindTemporaryExprs. Otherwise we can end up forgetting to destroy
temporary objects used to construct a constructor parameter.

Added: 
    clang/test/CodeGenCXX/instantiate-init.cpp

Modified: 
    clang/lib/Sema/TreeTransform.h

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 1bff267cffc8..1da28a3bb94c 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -12241,7 +12241,8 @@ TreeTransform<Derived>::TransformCXXConstructExpr(CXXConstructExpr *E) {
         (E->getNumArgs() > 1 && getDerived().DropCallArgument(E->getArg(1)))) &&
        (!getDerived().DropCallArgument(E->getArg(0))) &&
        !E->isListInitialization()))
-    return getDerived().TransformExpr(E->getArg(0));
+    return getDerived().TransformInitializer(E->getArg(0),
+                                             /*DirectInit*/ false);
 
   TemporaryBase Rebase(*this, /*FIXME*/ E->getBeginLoc(), DeclarationName());
 

diff  --git a/clang/test/CodeGenCXX/instantiate-init.cpp b/clang/test/CodeGenCXX/instantiate-init.cpp
new file mode 100644
index 000000000000..dd8a1a13bdf0
--- /dev/null
+++ b/clang/test/CodeGenCXX/instantiate-init.cpp
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -std=c++14 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -std=c++17 %s -emit-llvm -o - | FileCheck %s
+
+namespace std {
+  template<typename T> class initializer_list {
+    const T *data;
+    __SIZE_TYPE__ size;
+
+  public:
+    initializer_list();
+  };
+}
+
+namespace ParenBraceInitList {
+  struct Vector {
+    Vector(std::initializer_list<int>);
+    ~Vector();
+  };
+
+  struct Base { Base(Vector) {} };
+
+  // CHECK: define {{.*}}18ParenBraceInitList1fILi0EE
+  template<int> void f() {
+    // CHECK: call {{.*}}18ParenBraceInitList6VectorC1
+    // CHECK: call {{.*}}18ParenBraceInitList6VectorD1
+    Base({0});
+  }
+  template void f<0>();
+}