static_variables should be treated the same way as all other
op_array components nowadays (only static_variables_ptr is
special). There's no need to persist/serialize it is separately
per shared op_array.
Currently, dynamically declared functions and closures are inserted
into the function table under a runtime definition key, and then later
possibly renamed. When opcache is not used and a file containing a
closure is repeatedly included, this leads to a very large memory leak,
as the no longer needed closure declarations will never be freed
(https://bugs.php.net/bug.php?id=76982).
With this patch, dynamic functions are instead stored in a
dynamic_func_defs member on the op_array, which opcodes reference
by index. When the parent op_array is destroyed, the dynamic_func_defs
it contains are also destroyed (unless they are stilled used elsewhere,
e.g. because they have been bound, or are used by a live closure). This
resolves the fundamental part of the leak, though doesn't completely
fix it yet due to some arena allocations.
The main non-obvious change here is to static variable handling:
We can't destroy static_variables_ptr in destroy_op_array, as e.g.
that would clear the static variables in a dynamic function when
the op_array containing it is destroyed. Static variable destruction
is separated out for this reason (we already do static variable
destruction separately for normal functions, so we only need to
handle main scripts).
Closes GH-5595.
When a method is inherited, the static variables will now always
use the initial values, rather than the values at the time of
inheritance. As such, behavior no longer depends on whether
inheritance happens before or after a method has been called.
This is implemented by always keeping static_variables as the
original values, and static_variables_ptr as the modified copy.
Closes GH-6705.
This is a new transparent technology that eliminates overhead of PHP class inheritance.
PHP classes are compiled and cached (by opcahce) separately, however their "linking" was done at run-time - on each request. The process of "linking" may involve a number of compatibility checks and borrowing methods/properties/constants form parent and traits. This takes significant time, but the result is the same on each request.
Inheritance Cache performs "linking" for unique set of all the depending classes (parent, interfaces, traits, property types, method types involved into compatibility checks) once and stores result in opcache shared memory. As a part of the this patch, I removed limitations for immutable classes (unresolved constants, typed properties and covariant type checks). So now all classes stored in opcache are "immutable". They may be lazily loaded into process memory, if necessary, but this usually occurs just once (on first linking).
The patch shows 8% improvement on Symphony "Hello World" app.
We're starting to see a mix between uses of zend_bool and bool.
Replace all usages with the standard bool type everywhere.
Of course, zend_bool is retained as an alias.
There should not be any need to persist references, and it's unlikely
that persisting a reference will behave correctly at runtime, because
we don't have a concept of an immutable reference.
For php-ast interning the file name is an effective memory leak,
see php-ast#134.
I don't think there's any reason to do this. At some point this
was needed due to bugs in the interned string mechanism that
caused issues if the string was later interned, e.g. through a
__FILE__ reference. These issues have since been resolved.
In conjunction with the filenames_table removal in c4016ecd44
this means that filenames now need to be refcounted like normal
strings. In particular the filename reference in op_arrays and CEs
are refcounted.
From an engine perspective, named parameters mainly add three
concepts:
* The SEND_* opcodes now accept a CONST op2, which is the
argument name. For now, it is looked up by linear scan and
runtime cached.
* This may leave UNDEF arguments on the stack. To avoid having
to deal with them in other places, a CHECK_UNDEF_ARGS opcode
is used to either replace them with defaults, or error.
* For variadic functions, EX(extra_named_params) are collected
and need to be freed based on ZEND_CALL_HAS_EXTRA_NAMED_PARAMS.
RFC: https://wiki.php.net/rfc/named_params
Closes GH-5357.
Tricky edge case: We inherit a property from an internal class,
in which case no property duplication takes place. We should not
try to persist the property info in that case. This didn't really
matter previously, but now that the property has some non-interned
owned data (the type), we need to make sure we don't try to free
that.
If opcache.record_warnings is enabled, opcache will record
compilation warnings and replay them when the file is included
again. The primary use case I have in mind for this is automated
testing of the opcache file cache.
This resolves bug #76535.
Currently, trait methods are aliased will continue to use the
original function name. In a few places in the codebase, we will
try to look up the actual method name instead. However, this does
not work if an aliased method is used indirectly
(https://bugs.php.net/bug.php?id=69180).
I think it would be better to instead actually change the method
name to the alias. This is in principle easy: We have to allow
function_name to be changed even if op array is otherwise shared
(similar to static_variables). This means we need to addref/release
the function_name separately, but I don't think there is a
performance concern here (especially as everything is usually
interned).
There is a bit of complication in opcache, where we need to make
sure that the function name is released the correct number of times
(interning may overwrite the name in the original op_array, but we
need to release it as many times as the op_array is shared).
Fixes bug #69180.
Fixes bug #74939.
Closes GH-5226.
Instead of having a completely independent encoding for type list
entries. This is going to use more memory, but I'm not particularly
concerned about that, as type unions that contain multiple classes
should be uncommon. On the other hand, this allows us to treat
top-level types and types inside lists mostly the same.
A new ZEND_TYPE_FOREACH macros allows to transparently treat list
and non-list types the same way. I'm not using it everywhere it could be
used for now, just the places that seemed most obvious.
Of course, this will make any future type system changes much simpler,
as it will not be necessary to duplicate all logic two times.
According to RFC: https://wiki.php.net/rfc/union_types_v2
The type representation now makes use of both the pointer payload
and the type mask at the same time. Additionall, zend_type_list is
introduced as a new kind of pointer payload, which is used to store
multiple class types. Each of the class types is a tagged pointer,
which may be either a class name or class entry. The latter is only
used for typed properties, while arguments/returns will instead use
cache slots. A type list can contain a mix of both names and CEs at
the same time, as not all classes may be resolvable.
One thing this is missing is support for union types in arginfo
and stubs, which I want to handle separately.
I've also dropped the special object code from the JIT implementation
for now -- I plan to add this back in a different form at a later time.
For now I did not want to include non-trivial JIT changes together
with large functional changes.
Another possible piece of follow-up work is to implement "iterable"
as an internal alias for "array|Traversable". I believe this will
eliminate quite a few special-cases that had to be implemented.
Closes GH-4838.
We now store the pointer payload and the type mask separately. This
is in preparation for union types, where we will be using both at
the same time.
To avoid increasing the size of arginfo structures, the
pass_by_reference and is_variadic fields are now stored as part of
the type_mask (8-bit are reserved for custom use).
Different types of pointer payloads are distinguished based on bits
in the type_mask.
Split out the simple equality check into an inline function --
this is one of the common cases.
Replace instanceof_function_ex with zend_class_implements_interface.
There are a few more places where it may be used.
