When a global jump occurs, look at the catch handler table to determine where to jump.
In that case, `pc` already shows the following instruction, but since the table shows `begin_offset ... end_offset`, the comparison is done with `begin_offset < pc && pc <= end_offset`.
If there is a corresponding handler, move `pc` to `handler.target_offset` and continue running the VM.
When a global jump across `ensure` is made by `return`, `break`, `next`, `redo` and `retry`, the extended `RBreak` object saves and restores the C-level execution position.
This extended `RBreak` can have tag information, which makes it a pseudo coroutine (the "tag" mimics CRuby).
The implementation of pseudo coroutines by `RBreak` is summarized by `CHECKPOINT_RESTORE ... CHECKPOINT_MAIN ... CHECKPOINT_END` and `throw_tagged_break` / `unwind_ensure` macros.
The restart of processing is branched by `RBREAK_TAG_FOREACH(DISPATCH_CHECKPOINTS)`.
- Not only `rescue` blocks but also `ensure` blocks are now sandwiched between `OP_EXCEPT` and `OP_RAISEIF`.
- Remove the function `ecall()`.
It is no longer necessary to re-enter the VM to perform an "ensure block".
This will resolves#1888.
- Added instruction `OP_JUW` (Jump while UnWind).
It jumps unconditionally like `OP_JMP`, but searches the catch handler table and executes the ensure block.
Since it searches the catch handler table, it is much heavier than `OP_JMP`.
- `OP_EXCEPT` checks if `mrb->exc` is `NULL`, `MRB_TT_EXCEPTION` or
`MRB_TT_BREAK`.
If `mrb->exc` is `NULL`, it will be replaced with `nil`.
- If `OP_RAISE` is `nil`, it does nothing and the immediately
following instruction is executed (like `OP_NOP`).
Also, in case of `RBreak` object, it moves to the processing for
`break`.
With this change, the instruction name is changed from
`OP_RAISE` to `OP_RAISEIF`.
The catch handler table is combined with iseq block.
This is to prevent the structure from growing by adding a field for the
catch handler table to the `mrb_irep` structure.
"iseq block" and "catch handler table":
[number of catch handler table (2 bytes)]
[number of byte code (4 bytes)]
[iseq (any bytes)]
[catch handlers (multiple of 7 bytes)]
catch handler:
[catch type (1 byte)]
[begin offset (2 bytes)]
[end offset (2 bytes)]
[target offset (2 bytes)]
catch type: enum mrb_catch_type (0 = rescue, 1 = ensure)
begin offset: Includes the specified instruction address
end offset: Does not include the specified instruction address
target offset: replaces pc with the specified instruction address
This table is not expanded by `read_irep_record_1()`.
The necessary elements are expanded one by one when used.
Introduced `MRB_NO_METHOD_CACHE` which is inverse of `MRB_METHOD_CACHE`
that should be enabled intestinally. In addition, the default cache is
made bigger (128 -> 256).
Type `mrbc -S -B<init> -o<outfile> <rbfiles...>` to generate the C
source code that holds compiled `mrb_irep`.
Appending the following code to the bottom of the generated code,
`mruby` executes the compiled code:
```C
int
main()
{
mrb_state *mrb = mrb_open();
struct RProc *p = mrb_proc_new(mrb, &init_irep);
mrb_vm_run(mrb, p, mrb_top_self(mrb), 0);
mrb_close(mrb);
return 0;
}
```
Eventually static compile should use this representation, instead
of `uint8_t` array that holds `mrb` data, so that we can skip
interpreting `mrb` data.
Changes:
- `pool format is completely replaced
- supported types: `STR`, `INT32`, `INT64`, `FLOAT`
- `FLOAT` may be replaced by binary representation in the future
- insert `NUL` after string literals in `mrb` files
- `irep->pool` no longer store values in `mrb_value`
- instead it stores in `mrb_pool_value`
- less allocation
- `mrb_irep` can be stored in ROM
Where `QSYM` means quoted symbols, which cannot be represented C
symbols, so specify aliases instead.
- operators: name of the operation, e.g. add for `+`
- predicates: add `_p` suffix instead of `?`
- bang methods: add `_b` suffix instead of `!`
- instance variables: add `a_` prefix instead of `@`
- global variables: add `d_` prefix instead of `@`
- class variables: unsupported; don't use them
Adding MRB_MINGW32_LEGACY in common.h in order to identify the legacy MinGW environment (i.e. NOT to be confused with MinGW-w64).
For more info about MinGW defined macros, see: https://sourceforge.net/p/predef/wiki/Compilers/
dearblue