r241038 - [MS ABI] Workaround corner-case bug in the ABI for operator delete

[David Majnemer]

Author: majnemer
Date: Mon Jun 29 22:30:26 2015
New Revision: 241038

URL: http://llvm.org/viewvc/llvm-project?rev=241038&view=rev
Log:
[MS ABI] Workaround corner-case bug in the ABI for operator delete

MSVC only genreates array cookies if the class has a destructor.  This
is problematic when having to call T::operator delete[](void *, size_t)
because the second argument's argument is impossible to synthesize
correctly if the class has no destructor (because there will be no array
cookie).

Instead, MSVC passes the size of the class.  Do the same, for
compatibility, instead of crashing.

This fixes PR23990.

Modified:
    cfe/trunk/lib/CodeGen/CGExprCXX.cpp
    cfe/trunk/test/CodeGenCXX/microsoft-abi-array-cookies.cpp

Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=241038&r1=241037&r2=241038&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Mon Jun 29 22:30:26 2015
@@ -1548,7 +1548,8 @@ namespace {
         // The size of an element, multiplied by the number of elements.
         llvm::Value *Size
           = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity());
-        Size = CGF.Builder.CreateMul(Size, NumElements);
+        if (NumElements)
+          Size = CGF.Builder.CreateMul(Size, NumElements);
 
         // Plus the size of the cookie if applicable.
         if (!CookieSize.isZero()) {

Modified: cfe/trunk/test/CodeGenCXX/microsoft-abi-array-cookies.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/microsoft-abi-array-cookies.cpp?rev=241038&r1=241037&r2=241038&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/microsoft-abi-array-cookies.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/microsoft-abi-array-cookies.cpp Mon Jun 29 22:30:26 2015
@@ -58,4 +58,14 @@ void check_array_cookies_aligned() {
 // CHECK: getelementptr inbounds i8, i8* [[ARRAY_AS_CHAR]], i64 -8
 }
 
+namespace PR23990 {
+struct S {
+  char x[42];
+  void operator delete[](void *p, __SIZE_TYPE__);
+  // CHECK-LABEL: define void @"\01?delete_s at PR23990@@YAXPAUS at 1@@Z"(
+  // CHECK: call void @"\01??_VS at PR23990@@SAXPAXI at Z"(i8* {{.*}}, i32 42)
+};
+void delete_s(S *s) { delete[] s; }
+}
+
 // CHECK: attributes [[NUW]] = { nounwind{{.*}} }