Fix throwing of exceptions within a generator

If a generator threw an exception and was iterated using foreach (i.e. not
manually) an infinite loop was triggered. The reason was that the

Fix throwing of exceptions within a generator

If a generator threw an exception and was iterated using foreach (i.e. not
manually) an infinite loop was triggered. The reason was that the exception
was not properly rethrown using zend_throw_exception_internal.

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Move a variable

Remove asterix modifier (*) for generators

Generators are now automatically detected by the presence of a `yield`
expression in their body.

This removes the ZEND_SUSPEND_AND_RET

Remove asterix modifier (*) for generators

Generators are now automatically detected by the presence of a `yield`
expression in their body.

This removes the ZEND_SUSPEND_AND_RETURN_GENERATOR opcode. Instead
additional checks for ZEND_ACC_GENERATOR are added to the fcall_common
helper and zend_call_function.

This also adds a new function zend_generator_create_zval, which handles
the actual creation of the generator zval from an op array.

I feel like I should deglobalize the zend_create_execute_data_from_op_array
code a bit. It currently changes EG(current_execute_data) and
EG(opline_ptr) which is somewhat confusing (given the name).

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Add support by yielding by-reference

Pass zend_generator directly to Zend VM

Previously the zval* of the generator was passed into the VM by misusing
EG(return_value_ptr_ptr). Now the zend_generator* itself is directly pass

Pass zend_generator directly to Zend VM

Previously the zval* of the generator was passed into the VM by misusing
EG(return_value_ptr_ptr). Now the zend_generator* itself is directly passed
in. This saves us from always having to pass the zval* around everywhere.

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Fix segfault in method test

A ref has to be added to $this if the generator is called !nested (which
is the case when it is invoked via getIterator).

Fix thread safe build

Add sceleton for yield* expression

This does not yet actually implement any delegation.

Fix backtraces and func_get_args()

To make the generator function show up in backtraces one has to insert an
additional execute_data into the chain, as prev_execute_data->function_state

Fix backtraces and func_get_args()

To make the generator function show up in backtraces one has to insert an
additional execute_data into the chain, as prev_execute_data->function_state
is used to determine the called function.

Adding the additional stack frame is also required for func_get_args(), as
the arguments are fetched from there too. The arguments have to be copied
in order to keep them around. Due to the way they are saved doing so is
quite ugly, so I added another function zend_copy_arguments to zend_execute.c
which handles this.

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Allow yielding during function calls

During function calls arguments are pushed onto the stack. Now these are
backed up on yield and restored on resume. This requires memcpy'ing them,

Allow yielding during function calls

During function calls arguments are pushed onto the stack. Now these are
backed up on yield and restored on resume. This requires memcpy'ing them,
but there doesn't seem to be any better way to do it.

Also this fixes the issue with exceptions thrown during function calls.

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Allow throwing exceptions from generators

The missing piece is how one can find the next stack frame, which is
required for dtor'ing arguments pushed to the stack. As the generator
e

Allow throwing exceptions from generators

The missing piece is how one can find the next stack frame, which is
required for dtor'ing arguments pushed to the stack. As the generator
execute_data does not live on the stack one can't use it to figure out the
start of the next stack frame. So there must be some other method.

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Add auto-increment keys

When no key is explicitely yielded PHP will used auto-incrementing keys
as a fallback. They behave the same as with arrays, i.e. the key is the
successor of t

Add auto-increment keys

When no key is explicitely yielded PHP will used auto-incrementing keys
as a fallback. They behave the same as with arrays, i.e. the key is the
successor of the largest previously used integer key.

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Add support for yielding keys

Keys are yielded using the

yield $key => $value

syntax. Currently this is implemented as a statement only and not as an
expression, be

Add support for yielding keys

Keys are yielded using the

yield $key => $value

syntax. Currently this is implemented as a statement only and not as an
expression, because conflicts arise considering nesting and use in arrays:

yield yield $a => $b;
// could be either
yield (yield $a) => $b;
// or
yield (yield $a => $b);

Once I find some way to resolve these conflicts this should be available
as an expression too.

Also the key yielding code is rather copy-and-past-y for the value yielding
code, so that should be factored out.

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Allow to use yield without value

If the generator is used as a coroutine it often doesn't make sense to yield
anything. In this case one can simply receive values using

$val

Allow to use yield without value

If the generator is used as a coroutine it often doesn't make sense to yield
anything. In this case one can simply receive values using

$value = yield;

The yield here will simply yield NULL.

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Add support for $generator->send()

Yield now is an expression and the return value is the value passed to
$generator->send(). By default (i.e. if ->next() is called) the value is
NUL

Add support for $generator->send()

Yield now is an expression and the return value is the value passed to
$generator->send(). By default (i.e. if ->next() is called) the value is
NULL.

Unlike in Python ->send() can be run without priming the generator with a
->next() call first.

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Make the GOTO and SWITCH VMs work again

Properly free resources when generator return value not used

To keep things clean two new functions are introduced:

zend_clean_and_cache_symbol_table(HashTable *symbol_table)
ze

Properly free resources when generator return value not used

To keep things clean two new functions are introduced:

zend_clean_and_cache_symbol_table(HashTable *symbol_table)
zend_free_compiled_variables(zval ***CVs, int num)

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Fix generator creation when execute_data is not nested

This happens primarily when the generator is invoked from some internal
place like a dynamic function call.

Free loop variables

If the generator is closed before it has finished running, it may happen
that some FREE or SWITCH_FREE opcodes haven't been executed and memory is
leaked.

Free loop variables

If the generator is closed before it has finished running, it may happen
that some FREE or SWITCH_FREE opcodes haven't been executed and memory is
leaked.

This fixes it by walking the brk_cont_array and manually freeing the
variables.

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Add support for generator methods

Close generator on return

Implement return for generators

For generators ZEND_RETURN directly calls ZEND_VM_RETURN(), thus passing
execution back to the caller (zend_generator_resume).

This commit also a

Implement return for generators

For generators ZEND_RETURN directly calls ZEND_VM_RETURN(), thus passing
execution back to the caller (zend_generator_resume).

This commit also adds a check that only return; is used in generators and
not return $value;.

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Add YIELD opcode implementation

Add support for executing a zend_execute_data

This adds another function execute_ex(), which accepts a zend_execute_data
struct to run (contrary to execute(), which accepts a zend_op_arr

Add support for executing a zend_execute_data

This adds another function execute_ex(), which accepts a zend_execute_data
struct to run (contrary to execute(), which accepts a zend_op_array from
which it initialized the execute_data).

This needs a bit more cleanup.

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Add initial code for suspending execution

This is just some initial code, which is still quite broken (and needs to be
moved so it can be reused.)