clang/test/Modules/placement-new-reachable.cpp

   1 // RUN: rm -rf %t
   2 // RUN: mkdir -p %t
   3 // RUN: split-file %s %t
   4 //
   5 // RUN: %clang_cc1 -std=c++20 %t/A.cppm -emit-module-interface -o %t/A.pcm
   6 // RUN: %clang_cc1 -std=c++20 %t/Use.cpp -fprebuilt-module-path=%t -fsyntax-only -verify
   7
   8 // RUN: %clang_cc1 -std=c++20 %t/A.cppm -emit-reduced-module-interface -o %t/A.pcm
   9 // RUN: %clang_cc1 -std=c++20 %t/Use.cpp -fprebuilt-module-path=%t -fsyntax-only -verify
  10
  11 //--- placement.h
  12 namespace std {
  13   using size_t = decltype(sizeof(0));
  14 }
  15 void *operator new(std::size_t, void *p) { return p; }
  16
  17 //--- A.cppm
  18 module;
  19 #include "placement.h"
  20 export module A;
  21 export template<class T>
  22 struct A {
  23     A(void *p) : ptr(new (p) T(43)) {}
  24 private:
  25     void *ptr;
  26 };
  27
  28 export struct B {
  29     B(void *p) : ptr(new (p) int(43)) {}
  30 private:
  31     void *ptr;
  32 };
  33
  34 // The use of operator new in the current module unit is only in the non-inline
  35 // function definitions. So it may be optimized out.
  36 using ::operator new;
  37
  38 //--- Use.cpp
  39 // expected-no-diagnostics
  40 import A;
  41 void bar(int *);
  42 void foo(void *ptr) {
  43     A<int> a(nullptr); // Good. It should be OK to construct A.
  44     B b(nullptr);
  45     void *p = ::operator new(sizeof(int), ptr); // Bad. The placement allocation in module A is not visible.
  46     void *q = new (ptr) int(43); // Good. We don't call the placement allocation function directly.
  47 }