JIT: Fix zend_jit_trace_find_init_fcall_op() - #23449
Open
arnaud-lb wants to merge 1 commit into
Open
Conversation
zend_jit_trace_find_init_fcall_op() tries to find the INIT_FCALL opline corresponding to a ZEND_JIT_TRACE_INIT_CALL record, but it fails to do so in the ZEND_JIT_TRACE_FAKE_INIT_CALL case, for nested calls. The first loop is supposed to find the first opline after the sequence of ZEND_JIT_TRACE_INIT_CALL record, but it mistakenly decrements 'p' after initially incrementing it. As a result 'p' eventually points to an invalid record. It works for non-nested calls because the 'p->op == ZEND_JIT_TRACE_VM' condition is true on the first iteration in that case. This can not lead to a crash or miscompilations, but this results in lost optimization opportunities.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
zend_jit_trace_find_init_fcall_op()tries to find theINIT_FCALLopline corresponding to aZEND_JIT_TRACE_INIT_CALLrecord, but it fails to do so in theZEND_JIT_TRACE_FAKE_INIT_CALLcase, for nested calls.The
ZEND_JIT_TRACE_FAKE_INIT_CALLcase implies thatppoints to a sequence ofZEND_JIT_TRACE_INIT_CALLtrace records. The first loop inzend_jit_trace_find_init_fcall_op()is supposed to find the firstoplineafter the sequence, but it mistakenly decrementspafter initially incrementing it. As a resultpeventually points to an invalid record.It works for non-nested calls because the
p->op == ZEND_JIT_TRACE_VMcondition is true on the first iteration in that case.This can not lead to a crash or miscompilations, but this results in lost optimization opportunities.