We transform the arrow function by nesting the expression into a return
statement. If we compile the arrow function twice this would be done twice,
leading to a compile assertion.
Fix oss-fuzz #60411
Closes GH-11632
Normally, PHP evaluates all expressions in offsets (property or array), as well
as the right hand side of assignments before actually fetching the offsets. This
is well explained in this blog post.
https://www.npopov.com/2017/04/14/PHP-7-Virtual-machine.html#writes-and-memory-safety
For ??= we have a bit of a problem in that the rhs must only be evaluated if the
lhs is null or undefined. Thus, we have to first compile the lhs with BP_VAR_IS,
conditionally run the rhs and then re-fetch the lhs with BP_VAR_W to to make
sure the offsets are valid if they have been invalidated.
However, we don't want to just re-evaluate the entire lhs because it may contain
side-effects, as in $array[$x++] ??= 42;. In this case, we don't want to
re-evaluate $x++ because it would result in writing to a different offset than
was previously tested. The same goes for function calls, like
$array[foo()] ??= 42;, where the second call to foo() might result in a
different value. PHP behaves correctly in these cases. This is implemented by
memoizing sub-expressions in the lhs of ??= and reusing them when compiling the
lhs for the second time. This is done for any expression that isn't a variable,
i.e. anything that can (potentially) be written to.
Unfortunately, this also means that function calls are considered writable due
to their return-by-reference semantics, and will thus not be memoized. The
expression foo()['bar'] ??= 42; will invoke foo() twice. Even worse,
foo(bar()) ??= 42; will call both foo() and bar() twice, but
foo(bar() + 1) ??= 42; will only call foo() twice. This is likely not by design,
and was just overlooked in the implementation. The RFC does not specify how
function calls in the lhs of the coalesce assignment behaves. This should
probably be improved in the future.
Now, the problem this commit actually fixes is that ??= may memoize expressions
inside assert() function calls that may not actually execute. This is not only
an issue when using the VAR in the second expression (which would usually also
be skipped) but also when freeing the VAR. For this reason, it is not safe to
memoize assert() sub-expressions.
There are two possible solutions:
1. Don't memoize any sub-expressions of assert(), meaning they will execute
twice.
2. Throw a compile error.
Option 2 is not quite simple, because we can't disallow all memoization inside
assert(), as that would break assertions like assert($array[foo()] ??= 'bar');.
Code like this is highly unlikely (and dubious) but possible. In this case, we
would need to make sure that a memoized value could not be used across the
assert boundary it was created in. The complexity for this is not worthwhile. So
we opt for option 1 and disable memoization immediately inside assert().
Fixes GH-11580
Closes GH-11581
Having this lineno on the same last compiled element can lead to an incorrectly
covered line number.
if (true) {
if (false) {
echo 'Never executed';
}
} else {
}
The echo will be reported as covered because the JMP from the if (true) branch
to the end of the else branch has the same lineno as the echo.
This is lacking a test because zend_dump.c does not have access to
ctx->debug_level and I don't think it's worth adjusting all the cases.
Closes GH-11598
Depending on the order in which observers were installed, some observers might have been executed twice after removal of another observer. Also, adding an observer could produce a bogus pointer.
The block optimizer pass allows the use of sources of the preceding
block if the block is a follower and not a target. This causes issues
when trying to remove FREE instructions: if the source is not in the
block of the FREE, then the FREE and source are still removed. Therefore
the other successor blocks, which must consume or FREE the temporary,
will still contain the FREE opline. This opline will now refer to a
temporary that doesn't exist anymore, which most of the time results in
a crash. For these kind of non-local scenarios, we'll let the SSA
based optimizations handle those cases.
Closes GH-11251.
If we bind the class to the runtime slot even if we're not the ones who have
performed early binding we'll miss the redeclaration error in the
ZEND_DECLARE_CLASS_DELAYED handler.
Closes GH-11226
In older versions of GCC (<=4.5) designated initializers would not accept member
names nested inside anonymous structures. Instead, we need to use a positional
member wrapped in {}.
Fixes GH-11063
Closes GH-11212
ex->call is only set for user calls, we shouldn't access it here.
zend_unfinished_execution_gc_ex wouldn't actually use it for internal calls, so
it didn't cause any serious issues.
Closes GH-11208
There are more places in zend_hash.c where the resize happened after some values on the HashTable struct were set.
I reordered them all, but writing a test for these would rely on the particular amount of bytes allocated at given points in time.
This patch preserves the scratch registers of the SysV x86-64 ABI by storing
them to the stack and restoring them later. We need to do this to prevent the
registers of the caller from being corrupted. The reason these get corrupted
is because the compiler is unaware of the Valgrind replacement function and
thus makes assumptions about the original function regarding registers which
are not true for the replacement function.
For implementation I used a GCC and Clang attribute. A more general
approach would be to use inline assembly but that's also less portable
and quite hacky. This attributes is supported since GCC 7.x, but the
target option is only supported since 11.x. For Clang the target option
does not matter.
Closes GH-10221.
There is a typo which causes the AND and OR range inference to infer a
wider range than necessary. Fix this typo. There are many ranges for
which the inference is too wide, I just picked one for AND and one for
OR that I found through symbolic execution.
In this example test, the previous range inferred for test_or was [-27..-1]
instead of [-20..-1].
And the previous range inferred for test_and was [-32..-25]
instead of [-28..-25].
Closes GH-11170.
