Static proc objects defined as methods may be placed in 4-byte alignments in 32-bit environments.
This may be misinterpreted as an immediate value depending on the address.
Since C11 and C++11 have additional language features for byte alignment, corresponding compilers use them to define the `mrb_alignas()` macro.
For earlier compilers, they use their own extensions to define the `mrb_alignas()` macro.
GCC supports `__attribute__((aligned(alignment)))` since at least version 2.95.3 (1999).
https://gcc.gnu.org/onlinedocs/gcc-2.95.3/gcc_4.html#IDX305
According to GPT-4, support was added in version 2.7 (1995).
It is not known which version of Visual C++ added support for `__declspec(align(n))`.
According to GPT-4, at least Visual C++ 6.0 (1998) seems to support it.
Also, the documentation of past Intel C/C++ compilers that support `__declspec(align(n))` makes reference to support with Visual C++ 4.2 (1996).
https://www.intel.com/content/dam/www/public/ijkk/jp/ja/documents/developer/ccomp40j.pdf
There are two issues to be fixed:
- `mrb_irep` could leak if `mrb_calloc()` encountered an out-of-memory exception
- `mrb_proc_merge_lvar()` allocated one extra variable name.
`irep->lv` can always refer to only one less range than `irep->nlocals`.
Also, when `mrb_proc_merge_lvar()` extends `irep->lv`, `mrb_realloc()` with `NULL` has the same behavior as `mrb_malloc()`.
It used to check ci to be non NULL in line 37, but we silently assumed
ci was not NULL in the `else` clause too. So instead of checking NULL,
we add assertion. This incomplete check was found by clang-tidy.
The method introduced by #5979 causes a fault by swapping classes.
```console
% bin/mruby -e 'Method = Proc; p Object.method(:inspect)'
zsh: segmentation fault (core dumped) bin/mruby -e 'Method = Proc; p Object.method(:inspect)'
```
After applying this patch, a `TypeError` exception will be raised.
```console
% bin/mruby -e 'Method = Proc; p Object.method(:inspect)'
trace (most recent call last):
[1] -e:1
-e:1:in method: allocation failure of Proc (TypeError)
```
However, if the `mrb_vtype` is the same object, the same care must still be taken as before.
```console
% bin/mruby -e 'Method = Binding; p method(:puts).eval("12345")'
trace (most recent call last):
[1] -e:1
-e:1:in eval: wrong argument type nil (expected Proc) (TypeError)
```
Since `Env` objects are shared by Blocks/Procs in the same context,
making multiple aliases in one context screws up with alias names.
New implementation uses alias bodies (Procs) to refer new names.
As a side effect, `__callee__` stop working correctly for aliases.
To fix this `__callee__` problem, we need to keep alias method names in
`callinfo`, which consumes more memory. We are wondering that is worth
the compatibility.
Passing a proc generated by the following method to `mrb_yield()` or `mrb_yield_argv()` no longer causes `SIGSEGV`:
- C functions made into proc objects with `mrb_proc_new_cfunc()`.
- A proc object which is the top level of a program generated by `mrb_load_string_cxt()` etc. with `mrbc_context::no_exec` enabled.
See also: #5932
Internal functions can only be called from within the library.
Functions listed in `mruby/internal.h` can be called from:
* core (src/*.c)
* gems (mrbgems/**/*.c)
But not from the application linked with `libmruby`.
The Difference
Since Ruby1.9, the keyword arguments were emulated by Ruby using the hash
object at the bottom of the arguments. But we have gradually moved toward
keyword arguments separated from normal (positinal) arguments.
At the same time, we value compatibility, so that Ruby3.0 keyword
arguments are somewhat compromise. Basically, keyword arguments are
separated from positional arguments, except when the method does not
take any formal keyword arguments, given keyword arguments (packed
in the hash object) are considered as the last argument.
And we also allow non symbol keys in the keyword arguments. In that
case, those keys are just passed in the `**` hash (or raise
`ArgumentError` for unknown keys).
The Instruction Changes
We have changed `OP_SEND` instruction. `OP_SEND` instruction used to
take 3 operands, the register, the symbol, the number of (positional)
arguments. The meaning of the third operand has been changed. It is now
considered as `n|(nk<<4)`, where `n` is the number of positional
arguments, and `nk` is the number of keyword arguments, both occupies
4 bits in the operand.
The number `15` in both `n` and `nk` means variable sized arguments are
packed in the object. Positional arguments will be packed in the array,
and keyword arguments will be packed in the hash object. That means
arguments more than 14 values are always packed in the object.
Arguments information for other instructions (`OP_SENDB` and `OP_SUPER`)
are also changed. It works as the third operand of `OP_SEND`. the
difference between `OP_SEND` and `OP_SENDB` is just trivial. It assigns
`nil` to the block hidden arguments (right after arguments).
The instruction `OP_SENDV` and `OP_SENDVB` are removed. Those
instructions are replaced by `OP_SEND` and `OP_SENDB` respectively with
the `15` (variable sized) argument information.
Calling Convention
When calling a method, the stack elements shall be in the order of the
receiver of the method, positional arguments, keyword arguments and the
block argument. If the number of positional or keyword arugument (`n` or
`nk`) is zero, corresponding arguments will be empty. So when `n=0` and
`nk=0` the stack layout (from bottom to top) will be:
+-----------------------+
| recv | block (or nil) |
+-----------------------+
The last elements `block` should be explicitly filled before `OP_SEND`
or assigned to `nil` by `OP_SENDB` internally. In other words, the
following have exactly same behavior:
OP_SENDB clears `block` implicitly:
```
OP_SENDB reg sym 0
```
OP_SEND clears `block` implicitly:
```
OP_LOADNIL R2
OP_SEND R2 sym 0
```
When calling a method with only positional arguments (n=0..14) without
keyword arguments, the stack layout will be like following:
+--------------------------------------------+
| recv | arg1 | ... | arg_n | block (or nil) |
+--------------------------------------------+
When calling a method with arguments packed in the array (n=15) which
means argument splat (*) is used in the actual arguments, or more than
14 arguments are passed the stack layout will be like following:
+-------------------------------+
| recv | array | block (or nil) |
+-------------------------------+
The number of the actual arguments is determined by the length of the
argument array.
When keyword arguments are given (nk>0), keyword arguments are passed
between positional arguments and the block argument. For example, when
we pass one positional argument `1` and one keyword argument `a: 2`,
the stack layout will be like:
+------------------------------------+
| recv | 1 | :a | 2 | block (or nil) |
+------------------------------------+
Note that keyword arguments consume `2*nk` elements in the stack when
`nk=0..14` (unpacked).
When calling a method with keyword arguments packed in the hash object
(nk=15) which means keyword argument splat (**) is used or more than
14 keyword arguments in the actual arguments, the stack layout will
be like:
+------------------------------+
| recv | hash | block (or nil) |
+------------------------------+
Note for mruby/c
When mruby/c authors try to support new keyword arguments, they need
to handle the new meaning of the argument information operand. If they
choose not to support keyword arguments in mruby/c, it just raise
error when `nk` (taken by `(c>>4)&0xf`) is not zero. And combine
`OP_SENDV` behavior with `OP_SEND` when `n` is `15`.
If they want to support keyword arguments seriously, contact me at
<matz@ruby.or.jp> or `@yukihiro_matz`. I can help you.
Otherwise `target_class` can be lost when it differs from `proc`'s
`target_class`, e.g. when called from `instance_eval`.
Also we should not pass `target_class` to `MRB_OBJ_ALLOC` since it
checks instance type from the class, and `target_class` may not have
proper information. ref #5272
Previously the following code did not produce the expected results:
```ruby
bx = binding
block = bx.eval("a = 1; proc { a }")
bx.eval("a = 2")
p block.call # Expect 2 but return 1 due to a bug
```
The previous implementation of `Binding#eval` evaluated the code and then merged the top layer variables.
This patch will parse and expand the variable space before making a call to `eval`.
This means that the call to `Binding#eval` will do the parsing twice.
In addition, the following changes will be made:
- Make `mrb_parser_foreach_top_variable()`, `mrb_binding_extract_proc()` and `mrb_binding_extract_env()` functions private global functions.
- Remove the `posthook` argument from `mrb_exec_irep()`.
The `posthook` argument was introduced to implement the `binding` method.
This patch is unnecessary because it uses a different implementation method.
ref #5362fixed#5491
The following methods will be made static.
- `Class#new`
- `Proc#call`
- `Kernel#catch`
Previously, static const RProc could not be registered as a method, but this has been changed to allow it.
- Added to `mruby-binding-core`
- `Binding#local_variable_defined?`
- `Binding#local_variable_get`
- `Binding#local_variable_set`
- `Binding#local_variables`
- `Binding#receiver`
- `Binding#source_location`
- `Binding#inspect`
- Added to `mruby-proc-binding`
- `Proc#binding`
The reason for separating `Proc#binding` is that core-mrbgems has a method that returns a closure object to minimize possible problems with being able to manipulate internal variables.
By separating it as different mrbgem, each user can judge this problem and incorporate it arbitrarily.
Instead of including `mruby/presym.h` everywhere, we provided the
fallback `mruby/presym.inc` under `include/mruby` directory, and specify
`-I<build-dir>/include` before `-I<top-dir>/include` in `presym.rake`.
So even when someone drops `-I<build-dir>/include` in compiler options,
it just compiles without failure.
Previously I used the `RData` object to avoid a memory leak in `mrb_irep` if `src/load.c` failed.
ref: https://github.com/mruby/mruby/pull/4250
commit: f1523d2404
Considering that the `RProc` object will be created in the subsequent process, it is preferable to create the `RProc` object from the beginning.
Along with this, the inside of `read_irep()` is replaced with the processing centered on the `RProc` object.
The global function that returns the `mrb_irep` pointer is still provided for compatibility.
This enhances self-containment.
Previously `mrb_context::stack` had the current call level stack, but now it owns it.
The `mrb_context::stack` field, which is no longer needed, will be removed.
To be also able to build mruby without presym in the future. However,
`MRB_QSYM` has been removed and changed as follows:
### Example
| Type | Symbol | Previous Style | New Style |
|---------------------------|--------|------------------|----------------|
| Operator | & | MRB_QSYM(and) | MRB_OPSYM(and) |
| Class Variable | @@foo | MRB_QSYM(00_foo) | MRB_CVSYM(foo) |
| Instance Variable | @foo | MRB_QSYM(0_foo) | MRB_IVSYM(foo) |
| Method with Bang | foo! | MRB_QSYM(foo_b) | MRB_SYM_B(foo) |
| Method with Question mark | foo? | MRB_QSYM(foo_p) | MRB_SYM_Q(foo) |
| Mmethod with Equal | foo= | MRB_QSYM(foo_e) | MRB_SYM_E(foo) |
This change makes it possible to define, for example, `MRB_IVSYM(foo)` as
`mrb_intern_lit(mrb, "@" "foo")`, which is useful if we support building
without presym in the future.
dearblue