Since we cannot access backtrace position in cmmgen.ml anymore,
Cmm.raise_kind in removed. Instead, we use Lambda.raise_kind. When
assembly code is generated, we reset the backtrace position to 0 in the
case of regular raise. Importantly, the semantics remains the same.
Allocations ignored by this version
- Marshalling
- In the minor heap by natively-compiled OCaml code
Allocations potentially sampled
- In the major heap
- In the minor heap by C code and OCaml code in bytecode mode
The mechanism complicates the runtime system and is not very general
(only a few system functions are instrumented). There are other ways
to intercept system calls that are more general and require no
modification to the source code of the runtime system.