shafik created this revision.
shafik added reviewers: teemperor, aprantl, labath.
The overloaded `new operator` in `TestCppOperators.py` are working by accident.
Currently we have:
void *operator new(std::size_t size) { C* r = ::new C; r->custom_new = true;
return r; }
void *operator new[](std::size_t size) { C* r =
static_cast<C*>(std::malloc(size)); r->custom_new = true; return r; }
Which allocate a C using global new which invokes the constructor on the
allocated memory, it each one then proceeds to set the member variable
`custom_new` to `true` and returns the allocated memory.
This is incorrect code b/c the allocation function is supposed to allocate
memory, while the new expression which invokes this has the responsibility of
then invoking the constructor (if any) on the newly allocated object e.g.:
new struct C
So the constructor should be invoked again. IIUC currently because LLDB does
not create the implicit constructor when parsing the `DWARF` because it is
artificial, this results in construction being a no-op. If we OTOH explicitly
default the constructor:
C() = default;
The test no longer works since the in-class member initializer will be run and
sets the field back to false:
bool custom_new = false;
This behavior is a little surprising since I believe Sema should create the
constructor for us when running the expression but either that is not really
the case or there is some other piece that is missing.
https://reviews.llvm.org/D79251
Files:
lldb/test/API/lang/cpp/operators/main.cpp
Index: lldb/test/API/lang/cpp/operators/main.cpp
===================================================================
--- lldb/test/API/lang/cpp/operators/main.cpp
+++ lldb/test/API/lang/cpp/operators/main.cpp
@@ -4,8 +4,8 @@
struct B { int dummy = 2324; };
struct C {
- void *operator new(std::size_t size) { C* r = ::new C; r->custom_new = true;
return r; }
- void *operator new[](std::size_t size) { C* r =
static_cast<C*>(std::malloc(size)); r->custom_new = true; return r; }
+ void *operator new(std::size_t size) { void *p = ::operator new(size);
side_effect = 3; return p; }
+ void *operator new[](std::size_t size) { void *p = ::operator new(size);
side_effect = 4; return p; }
void operator delete(void *p) { std::free(p); side_effect = 1; }
void operator delete[](void *p) { std::free(p); side_effect = 2; }
@@ -171,8 +171,8 @@
//% self.expect("expr static_cast<long>(c)", endstr=" 12\n")
//% self.expect("expr c.operatorint()", endstr=" 13\n")
//% self.expect("expr c.operatornew()", endstr=" 14\n")
- //% self.expect("expr (new struct C)->custom_new", endstr=" true\n")
- //% self.expect("expr (new struct C[1])->custom_new", endstr=" true\n")
+ //% self.expect("expr (new struct C); side_effect", endstr=" = 3\n")
+ //% self.expect("expr (new struct C[1]); side_effect", endstr=" = 4\n")
//% self.expect("expr delete c2; side_effect", endstr=" = 1\n")
//% self.expect("expr delete[] c3; side_effect", endstr=" = 2\n")
delete c2;
Index: lldb/test/API/lang/cpp/operators/main.cpp
===================================================================
--- lldb/test/API/lang/cpp/operators/main.cpp
+++ lldb/test/API/lang/cpp/operators/main.cpp
@@ -4,8 +4,8 @@
struct B { int dummy = 2324; };
struct C {
- void *operator new(std::size_t size) { C* r = ::new C; r->custom_new = true; return r; }
- void *operator new[](std::size_t size) { C* r = static_cast<C*>(std::malloc(size)); r->custom_new = true; return r; }
+ void *operator new(std::size_t size) { void *p = ::operator new(size); side_effect = 3; return p; }
+ void *operator new[](std::size_t size) { void *p = ::operator new(size); side_effect = 4; return p; }
void operator delete(void *p) { std::free(p); side_effect = 1; }
void operator delete[](void *p) { std::free(p); side_effect = 2; }
@@ -171,8 +171,8 @@
//% self.expect("expr static_cast<long>(c)", endstr=" 12\n")
//% self.expect("expr c.operatorint()", endstr=" 13\n")
//% self.expect("expr c.operatornew()", endstr=" 14\n")
- //% self.expect("expr (new struct C)->custom_new", endstr=" true\n")
- //% self.expect("expr (new struct C[1])->custom_new", endstr=" true\n")
+ //% self.expect("expr (new struct C); side_effect", endstr=" = 3\n")
+ //% self.expect("expr (new struct C[1]); side_effect", endstr=" = 4\n")
//% self.expect("expr delete c2; side_effect", endstr=" = 1\n")
//% self.expect("expr delete[] c3; side_effect", endstr=" = 2\n")
delete c2;
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