[SemaCXX] Unconfuse Clang when std::align_val_t is unscoped in C++03

When -faligned-allocation is specified in C++03 libc++ defines std::align_val_t as an unscoped enumeration type (because Clang didn't provide scoped enumerations as an extension until 8.0). Unfortunately Clang confuses the `align_val_t` overloads of delete with the sized deallocation overloads which aren't enabled. This caused Clang to call the aligned deallocation function as if it were the sized deallocation overload. For example: https://godbolt.org/z/xXJELh This patch fixes the confusion. llvm-svn: 351294

Author: EricWF

clang/lib/Sema/SemaExprCXX.cpp

@@ -1511,11 +1511,19 @@ namespace {
  Destroying = true;
  ++NumBaseParams;
  }
- if (FD->getNumParams() == NumBaseParams + 2)
- HasAlignValT = HasSizeT = true;
- else if (FD->getNumParams() == NumBaseParams + 1) {
- HasSizeT = FD->getParamDecl(NumBaseParams)->getType()->isIntegerType();
- HasAlignValT = !HasSizeT;
+
+ if (NumBaseParams < FD->getNumParams() &&
+ S.Context.hasSameUnqualifiedType(
+ FD->getParamDecl(NumBaseParams)->getType(),
+ S.Context.getSizeType())) {
+ ++NumBaseParams;
+ HasSizeT = true;
+ }
+
+ if (NumBaseParams < FD->getNumParams() &&
+ FD->getParamDecl(NumBaseParams)->getType()->isAlignValT()) {
+ ++NumBaseParams;
+ HasAlignValT = true;
  }
 
  // In CUDA, determine how much we'd like / dislike to call this.

clang/test/SemaCXX/cxx03-aligned-allocation-unscoped-enum.cpp

@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -std=c++03 -triple x86_64-pc-linux-gnu %s \
+// RUN: -faligned-allocation -emit-llvm -o - -Wno-c++11-extensions | FileCheck %s
+
+// Ensure Clang doesn't confuse std::align_val_t with the sized deallocation
+// parameter when the enum type is unscoped. Libc++ does this in C++03 in order
+// to support aligned allocation in that dialect.
+
+using size_t = __decltype(sizeof(0));
+
+namespace std {
+enum align_val_t : size_t {};
+}
+_Static_assert(__is_same(__underlying_type(std::align_val_t), size_t), "");
+
+// CHECK-LABEL: define void @_Z1fPi(
+void f(int *p) {
+ // CHECK-NOT: call void @_ZdlPvSt11align_val_t(
+ // CHECK: call void @_ZdlPv(
+ // CHECK: ret void
+ delete p;
+}