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#define ANNOTATE(property) __attribute__((tag(property)))
struct Cell { int f; } ANNOTATE("GC Thing");
class AutoSuppressGC_Base {
public:
AutoSuppressGC_Base() {}
~AutoSuppressGC_Base() {}
} ANNOTATE("Suppress GC");
class AutoSuppressGC_Child : public AutoSuppressGC_Base {
public:
AutoSuppressGC_Child() : AutoSuppressGC_Base() {}
};
class AutoSuppressGC {
AutoSuppressGC_Child helpImBeingSuppressed;
public:
AutoSuppressGC() {}
};
extern void GC() ANNOTATE("GC Call");
void GC()
{
// If the implementation is too trivial, the function body won't be emitted at all.
asm("");
}
extern void foo(Cell*);
void suppressedFunction() {
GC(); // Calls GC, but is always called within AutoSuppressGC
}
void halfSuppressedFunction() {
GC(); // Calls GC, but is sometimes called within AutoSuppressGC
}
void unsuppressedFunction() {
GC(); // Calls GC, never within AutoSuppressGC
}
void f() {
Cell* cell1 = nullptr;
Cell* cell2 = nullptr;
Cell* cell3 = nullptr;
{
AutoSuppressGC nogc;
suppressedFunction();
halfSuppressedFunction();
}
foo(cell1);
halfSuppressedFunction();
foo(cell2);
unsuppressedFunction();
{
// Old bug: it would look from the first AutoSuppressGC constructor it
// found to the last destructor. This statement *should* have no effect.
AutoSuppressGC nogc;
}
foo(cell3);
}
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