Add a runtime API for reset shared heap(chain)

[TianlongLiang]

No description provided.

[yamt]

can you elaborate use cases a bit?

[TianlongLiang]

can you elaborate use cases a bit?

For example, if a WASM module calls shared_heap_malloc a few times and an exception occurs before it gets a chance to free it, then the WAMR runtime-managed shared heap will have some dangling pointer(some memory block can't be allocated) until the runtime destroys and reinitializes. This api provides a lighter way to reset(allow the whole WAMR runtime-managed shared heap to become allocatable) the shared heaps without re-initializing the runtime.

[yamt]

can you elaborate use cases a bit?

For example, if a WASM module calls shared_heap_malloc a few times and an exception occurs before it gets a chance to free it, then the WAMR runtime-managed shared heap will have some dangling pointer(some memory block can't be allocated) until the runtime destroys and reinitializes. This api provides a lighter way to reset(allow the whole WAMR runtime-managed shared heap to become allocatable) the shared heaps without re-initializing the runtime.

so,

• it's an equivalent of destroy + re-create
• not intended to be used for a chain being used by running instances

right?

[yamt]

is this a change for "fix some warnings"?
what warning?

[TianlongLiang]

warning: missing initializer for member ‘SharedHeapInitArgs::pre_allocated_addr’ [-Wmissing-field-initializers]
1081 |     SharedHeapInitArgs args = { 0 };

I simply replaced all occurrences in this file.

I remember that we had a discussion about the choice between {0} and {}, for C++, {} should be a more future-proof version, right?

[yamt]

does this mean that in some cases shared memory may have uninitialized user-visible contents?
is it documented somewhere?

[TianlongLiang]

Seems that on Linux it won't reset to 0(the commented-out lines will fail), though it should, given our implementation uses MAP_ANONYMOUS., I will dig into it

[TianlongLiang]

can you elaborate use cases a bit?

For example, if a WASM module calls shared_heap_malloc a few times and an exception occurs before it gets a chance to free it, then the WAMR runtime-managed shared heap will have some dangling pointer(some memory block can't be allocated) until the runtime destroys and reinitializes. This api provides a lighter way to reset(allow the whole WAMR runtime-managed shared heap to become allocatable) the shared heaps without re-initializing the runtime.

so,

• it's an equivalent of destroy + re-create
• not intended to be used for a chain being used by running instances

right?

Yes, you are right :)