[Clang] Support MSPropertyRefExpr as placement arg to new-expression (#75883)

It seems we were forgetting to call `checkArgsForPlaceholders` on the
placement arguments of new-expressions in Sema. I don't think that was
intended—at least doing so doesn't seem to break anything—so this pr
adds that.

This also fixes #65053

---------

Co-authored-by: Erich Keane <[email protected]>

Author: Sirraide

clang/docs/ReleaseNotes.rst

@@ -572,6 +572,30 @@ Improvements to Clang's diagnostics
   enclosing template must be a definition.
 - Clang now diagnoses function/variable templates that shadow their own template parameters, e.g. ``template<class T> void T();``.
 
+- Clang now emits more descriptive diagnostics for 'unusual' expressions (e.g. incomplete index
+  expressions on matrix types or builtin functions without an argument list) as placement-args
+  to new-expressions.
+
+  Before:
+
+  .. code-block:: text
+
+    error: no matching function for call to 'operator new'
+       13 |     new (__builtin_memset) S {};
+          |     ^   ~~~~~~~~~~~~~~~~~~
+
+    note: candidate function not viable: no known conversion from '<builtin fn type>' to 'int' for 2nd argument
+        5 |     void* operator new(__SIZE_TYPE__, int);
+          |           ^
+
+  After:
+
+  .. code-block:: text
+
+    error: builtin functions must be directly called
+       13 |     new (__builtin_memset) S {};
+          |          ^
+
 
 Improvements to Clang's time-trace
 ----------------------------------
@@ -774,6 +798,12 @@ Bug Fixes in This Version
 - Fix assertion failure when call noreturn-attribute function with musttail
   attribute.
   Fixes (`#76631 <https://github.com/llvm/llvm-project/issues/76631>`_)
+  - The MS ``__noop`` builtin without an argument list is now accepted
+  in the placement-args of new-expressions, matching MSVC's behaviour.
+- Fix an issue that caused MS ``__decspec(property)`` accesses as well as
+  Objective-C++ property accesses to not be converted to a function call
+  to the getter in the placement-args of new-expressions.
+  Fixes (`#65053 <https://github.com/llvm/llvm-project/issues/65053>`_)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/Sema/Sema.h

@@ -2112,6 +2112,10 @@ class Sema final {
 
   bool CheckFunctionReturnType(QualType T, SourceLocation Loc);
 
+  /// Check an argument list for placeholders that we won't try to
+  /// handle later.
+  bool CheckArgsForPlaceholders(MultiExprArg args);
+
   /// Build a function type.
   ///
   /// This routine checks the function type according to C++ rules and

clang/lib/Sema/SemaExpr.cpp

@@ -5058,8 +5058,6 @@ static QualType getDependentArraySubscriptType(Expr *LHS, Expr *RHS,
   return Result->isDependentType() ? Result : Ctx.DependentTy;
 }
 
-static bool checkArgsForPlaceholders(Sema &S, MultiExprArg args);
-
 ExprResult Sema::ActOnArraySubscriptExpr(Scope *S, Expr *base,
                                          SourceLocation lbLoc,
                                          MultiExprArg ArgExprs,
@@ -5163,7 +5161,7 @@ ExprResult Sema::ActOnArraySubscriptExpr(Scope *S, Expr *base,
       return ExprError();
     ArgExprs[0] = result.get();
   } else {
-    if (checkArgsForPlaceholders(*this, ArgExprs))
+    if (CheckArgsForPlaceholders(ArgExprs))
       return ExprError();
   }
 
@@ -6912,15 +6910,13 @@ static bool isPlaceholderToRemoveAsArg(QualType type) {
   llvm_unreachable("bad builtin type kind");
 }
 
-/// Check an argument list for placeholders that we won't try to
-/// handle later.
-static bool checkArgsForPlaceholders(Sema &S, MultiExprArg args) {
+bool Sema::CheckArgsForPlaceholders(MultiExprArg args) {
   // Apply this processing to all the arguments at once instead of
   // dying at the first failure.
   bool hasInvalid = false;
   for (size_t i = 0, e = args.size(); i != e; i++) {
     if (isPlaceholderToRemoveAsArg(args[i]->getType())) {
-      ExprResult result = S.CheckPlaceholderExpr(args[i]);
+      ExprResult result = CheckPlaceholderExpr(args[i]);
       if (result.isInvalid()) hasInvalid = true;
       else args[i] = result.get();
     }
@@ -7194,7 +7190,7 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation LParenLoc,
   if (Result.isInvalid()) return ExprError();
   Fn = Result.get();
 
-  if (checkArgsForPlaceholders(*this, ArgExprs))
+  if (CheckArgsForPlaceholders(ArgExprs))
     return ExprError();
 
   if (getLangOpts().CPlusPlus) {

clang/lib/Sema/SemaExprCXX.cpp

@@ -2286,6 +2286,9 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   bool PassAlignment = getLangOpts().AlignedAllocation &&
                        Alignment > NewAlignment;
 
+  if (CheckArgsForPlaceholders(PlacementArgs))
+    return ExprError();
+
   AllocationFunctionScope Scope = UseGlobal ? AFS_Global : AFS_Both;
   if (!AllocType->isDependentType() &&
       !Expr::hasAnyTypeDependentArguments(PlacementArgs) &&

clang/test/CodeGenCXX/ms-property-new.cpp

@@ -0,0 +1,52 @@
+// RUN: %clang_cc1 -emit-llvm -triple=x86_64-pc-win32 -fms-compatibility %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple=x86_64-pc-win32 -fms-compatibility -emit-pch -o %t %s
+// RUN: %clang_cc1 -emit-llvm -triple=x86_64-pc-win32 -fms-compatibility -include-pch %t -verify %s -o - | FileCheck %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+struct S {
+  int GetX() { return 42; }
+  __declspec(property(get=GetX)) int x;
+
+  int GetY(int i, int j) { return i+j; }
+  __declspec(property(get=GetY)) int y[];
+
+  void* operator new(__SIZE_TYPE__, int);
+};
+
+template <typename T>
+struct TS {
+  T GetT() { return T(); }
+  __declspec(property(get=GetT)) T t;
+
+  T GetR(T i, T j) { return i+j; }
+  __declspec(property(get=GetR)) T r[];
+};
+
+// CHECK-LABEL: main
+int main(int argc, char **argv) {
+  S *s;
+  TS<double> *ts;
+
+  // CHECK: [[X:%.+]] = call noundef i32 @"?GetX@S@@QEAAHXZ"(ptr {{[^,]*}} %{{.+}})
+  // CHECK-NEXT: call noundef ptr @"??2S@@SAPEAX_KH@Z"(i64 noundef 1, i32 noundef [[X]])
+  new (s->x) S;
+
+  // CHECK: [[Y:%.+]] = call noundef i32 @"?GetY@S@@QEAAHHH@Z"(ptr {{[^,]*}} %{{.+}}, i32 noundef 1, i32 noundef 2)
+  // CHECK-NEXT: call noundef ptr @"??2S@@SAPEAX_KH@Z"(i64 noundef 1, i32 noundef [[Y]])
+  new ((s->y)[1][2]) S;
+
+  // CHECK: [[T:%.+]] = call noundef double @"?GetT@?$TS@N@@QEAANXZ"(ptr {{[^,]*}} %{{.+}})
+  // CHECK-NEXT: [[TI:%.+]] = fptosi double [[T]] to i32
+  // CHECK-NEXT: call noundef ptr @"??2S@@SAPEAX_KH@Z"(i64 noundef 1, i32 noundef [[TI]])
+  new (ts->t) S;
+
+  // CHECK: [[R:%.+]] = call noundef double @"?GetR@?$TS@N@@QEAANNN@Z"(ptr {{[^,]*}} %{{.+}}, double {{[^,]*}}, double {{[^,]*}})
+  // CHECK-NEXT: [[RI:%.+]] = fptosi double [[R]] to i32
+  // CHECK-NEXT: call noundef ptr @"??2S@@SAPEAX_KH@Z"(i64 noundef 1, i32 noundef [[RI]])
+  new ((ts->r)[1][2]) S;
+}
+
+#endif

clang/test/CodeGenCXX/placement-new-ms-__noop.cpp

@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -fms-extensions -std=c++11 -emit-llvm -o - %s | FileCheck %s
+
+struct S {
+  void* operator new(__SIZE_TYPE__, int);
+};
+
+int main() {
+  // CHECK: call {{.*}} ptr @"??2S@@SAPEAX_KH@Z"(i64 {{.*}} 1, i32 {{.*}} 0)
+  // CHECK: call {{.*}} ptr @"??2S@@SAPEAX_KH@Z"(i64 {{.*}} 1, i32 {{.*}} 0)
+  new (__noop) S;
+  new ((__noop)) S;
+}

clang/test/CodeGenObjCXX/property-placement-new.mm

@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -x objective-c++ -std=c++11 %s -triple x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s
+
+// CHECK: [[NAME:@.*]] = private unnamed_addr constant [9 x i8] c"position\00"
+// CHECK: [[SEL:@.*]] = internal externally_initialized global ptr [[NAME]]
+
+@interface I {
+  int position;
+}
+@property(nonatomic) int position;
+@end
+
+struct S {
+  void *operator new(__SIZE_TYPE__, int);
+};
+
+template <typename T>
+struct TS {
+  void *operator new(__SIZE_TYPE__, T);
+};
+
+I *GetI();
+
+int main() {
+  @autoreleasepool {
+    // CHECK: [[I:%.+]] = alloca ptr
+    auto* i = GetI();
+    i.position = 42;
+
+    // This is so we can find the next line more easily.
+    // CHECK: store double
+    double d = 42.0;
+
+    // CHECK: [[I1:%.+]] = load ptr, ptr [[I]]
+    // CHECK-NEXT: [[SEL1:%.+]] = load ptr, ptr [[SEL]]
+    // CHECK-NEXT: [[POS1:%.+]] = call {{.*}} i32 @objc_msgSend(ptr {{.*}} [[I1]], ptr {{.*}} [[SEL1]])
+    // CHECK-NEXT: call {{.*}} ptr @_ZN1SnwEmi(i64 {{.*}} 1, i32 {{.*}} [[POS1]])
+    new (i.position) S;
+
+    // CHECK: [[I2:%.+]] = load ptr, ptr [[I]]
+    // CHECK-NEXT: [[SEL2:%.+]] = load ptr, ptr [[SEL]]
+    // CHECK-NEXT: [[POS2:%.+]] = call {{.*}} i32 @objc_msgSend(ptr {{.*}} [[I2]], ptr {{.*}} [[SEL2]])
+    // CHECK-NEXT: [[DBL:%.+]] = sitofp i32 [[POS2]] to double
+    // CHECK-NEXT: call {{.*}} ptr  @_ZN2TSIdEnwEmd(i64 {{.*}} 1, double {{.*}} [[DBL]])
+    new (i.position) TS<double>;
+  }
+}

clang/test/SemaCXX/builtin-std-move.cpp

@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -std=c++17 -verify %s
-// RUN: %clang_cc1 -std=c++17 -verify %s -DNO_CONSTEXPR
-// RUN: %clang_cc1 -std=c++20 -verify %s
+// RUN: %clang_cc1 -std=c++17 -verify=cxx17,expected %s
+// RUN: %clang_cc1 -std=c++17 -verify=cxx17,expected %s -DNO_CONSTEXPR
+// RUN: %clang_cc1 -std=c++20 -verify=cxx20,expected %s
 
 namespace std {
 #ifndef NO_CONSTEXPR
@@ -12,6 +12,7 @@ namespace std {
   template<typename T> CONSTEXPR T &&move(T &x) {
     static_assert(T::moveable, "instantiated move"); // expected-error {{no member named 'moveable' in 'B'}}
                                                      // expected-error@-1 {{no member named 'moveable' in 'C'}}
+                                                     // expected-error@-2 {{no member named 'moveable' in 'D'}}
     return static_cast<T&&>(x);
   }
 
@@ -23,6 +24,7 @@ namespace std {
 
   template<typename T> CONSTEXPR auto move_if_noexcept(T &x) -> typename ref<T, noexcept(T(static_cast<T&&>(x)))>::type {
     static_assert(T::moveable, "instantiated move_if_noexcept"); // expected-error {{no member named 'moveable' in 'B'}}
+                                                                 // expected-error@-1 {{no member named 'moveable' in 'D'}}
     return static_cast<typename ref<T, noexcept(T(static_cast<T&&>(x)))>::type>(x);
   }
 
@@ -36,6 +38,7 @@ namespace std {
   template<typename T> CONSTEXPR T &&forward(typename remove_reference<T>::type &x) {
     static_assert(T::moveable, "instantiated forward"); // expected-error {{no member named 'moveable' in 'B'}}
                                                         // expected-error@-1 {{no member named 'moveable' in 'C'}}
+                                                        // expected-error@-2 {{no member named 'moveable' in 'D'}}
     return static_cast<T&&>(x);
   }
   template<typename T> CONSTEXPR T &&forward(typename remove_reference<T>::type &&x) {
@@ -67,21 +70,25 @@ namespace std {
   CONSTEXPR auto forward_like(T &&t) -> ForwardLikeRetType<U, T> {
     using TT = typename remove_reference<T>::type;
     static_assert(TT::moveable, "instantiated as_const"); // expected-error {{no member named 'moveable' in 'B'}}
+                                                          // expected-error@-1 {{no member named 'moveable' in 'D'}}
     return static_cast<ForwardLikeRetType<U, T>>(t);
   }
 
   template<typename T> CONSTEXPR const T &as_const(T &x) {
     static_assert(T::moveable, "instantiated as_const"); // expected-error {{no member named 'moveable' in 'B'}}
+                                                         // expected-error@-1 {{no member named 'moveable' in 'D'}}
     return x;
   }
 
   template<typename T> CONSTEXPR T *addressof(T &x) {
     static_assert(T::moveable, "instantiated addressof"); // expected-error {{no member named 'moveable' in 'B'}}
+                                                          // expected-error@-1 {{no member named 'moveable' in 'D'}}
     return __builtin_addressof(x);
   }
 
   template<typename T> CONSTEXPR T *__addressof(T &x) {
     static_assert(T::moveable, "instantiated __addressof"); // expected-error {{no member named 'moveable' in 'B'}}
+                                                            // expected-error@-1 {{no member named 'moveable' in 'D'}}
     return __builtin_addressof(x);
   }
 }
@@ -116,42 +123,20 @@ A &forward_rval_as_lval() {
 }
 
 struct B {};
-B &&(*pMove)(B&) = std::move; // #1 expected-note {{instantiation of}}
-B &&(*pMoveIfNoexcept)(B&) = &std::move_if_noexcept; // #2 expected-note {{instantiation of}}
-B &&(*pForward)(B&) = &std::forward<B>; // #3 expected-note {{instantiation of}}
-B &&(*pForwardLike)(B&) = &std::forward_like<int&&, B&>; // #4 expected-note {{instantiation of}}
-const B &(*pAsConst)(B&) = &std::as_const; // #5 expected-note {{instantiation of}}
-B *(*pAddressof)(B&) = &std::addressof; // #6 expected-note {{instantiation of}}
-B *(*pUnderUnderAddressof)(B&) = &std::__addressof; // #7 expected-note {{instantiation of}}
+B &&(*pMove)(B&) = std::move;                            // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+B &&(*pMoveIfNoexcept)(B&) = &std::move_if_noexcept;     // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+B &&(*pForward)(B&) = &std::forward<B>;                  // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+B &&(*pForwardLike)(B&) = &std::forward_like<int&&, B&>; // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+const B &(*pAsConst)(B&) = &std::as_const;               // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+B *(*pAddressof)(B&) = &std::addressof;                  // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+B *(*pUnderUnderAddressof)(B&) = &std::__addressof;      // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
 int (*pUnrelatedMove)(B, B) = std::move;
 
 struct C {};
-C &&(&rMove)(C&) = std::move; // #8 expected-note {{instantiation of}}
-C &&(&rForward)(C&) = std::forward<C>; // #9 expected-note {{instantiation of}}
+C &&(&rMove)(C&) = std::move;          // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+C &&(&rForward)(C&) = std::forward<C>; // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
 int (&rUnrelatedMove)(B, B) = std::move;
 
-#if __cplusplus <= 201703L
-// expected-warning@#1 {{non-addressable}}
-// expected-warning@#2 {{non-addressable}}
-// expected-warning@#3 {{non-addressable}}
-// expected-warning@#4 {{non-addressable}}
-// expected-warning@#5 {{non-addressable}}
-// expected-warning@#6 {{non-addressable}}
-// expected-warning@#7 {{non-addressable}}
-// expected-warning@#8 {{non-addressable}}
-// expected-warning@#9 {{non-addressable}}
-#else
-// expected-error@#1 {{non-addressable}}
-// expected-error@#2 {{non-addressable}}
-// expected-error@#3 {{non-addressable}}
-// expected-error@#4 {{non-addressable}}
-// expected-error@#5 {{non-addressable}}
-// expected-error@#6 {{non-addressable}}
-// expected-error@#7 {{non-addressable}}
-// expected-error@#8 {{non-addressable}}
-// expected-error@#9 {{non-addressable}}
-#endif
-
 void attribute_const() {
   int n;
   std::move(n); // expected-warning {{ignoring return value}}
@@ -163,6 +148,22 @@ void attribute_const() {
   std::as_const(n); // expected-warning {{ignoring return value}}
 }
 
+struct D {
+  void* operator new(__SIZE_TYPE__, D&&(*)(D&));
+  void* operator new(__SIZE_TYPE__, D*(*)(D&));
+  void* operator new(__SIZE_TYPE__, const D&(*)(D&));
+};
+
+void placement_new() {
+  new (std::move<D>) D;             // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+  new (std::move_if_noexcept<D>) D; // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+  new (std::forward<D>) D;          // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+  new (std::forward_like<D>) D;     // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+  new (std::addressof<D>) D;        // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+  new (std::__addressof<D>) D;      // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+  new (std::as_const<D>) D;         // cxx17-warning {{non-addressable}} cxx20-error {{non-addressable}} expected-note {{instantiation of}}
+}
+
 namespace std {
   template<typename T> int &move(T);
 }