This commit adds an entry_exit field to block_t for use in invalidate_block_version(). By patching the start of the block while invalidating it, invalidate_block_version() can function correctly while there is no executable memory left for new branch stubs.
This change additionally fixes correctness for situations where we cannot patch incoming jumps to the invalidated block. In situations such as Shopify/yjit#226, the address to the start of the block is saved and used later, possibly after the block is invalidated.
The assume_* family of function now generate block->entry_exit before remembering blocks for invalidation.
RubyVM::YJIT.simulate_oom! is introduced for testing out of memory conditions. The test for it is disabled for now because OOM triggers other failure conditions not addressed by this commit.
Added by alanwu (Alan Wu) almost 4 years ago
YJIT: Make block invalidation more robust
This commit adds an entry_exit field to block_t for use in
invalidate_block_version(). By patching the start of the block while
invalidating it, invalidate_block_version() can function correctly
while there is no executable memory left for new branch stubs.
This change additionally fixes correctness for situations where we
cannot patch incoming jumps to the invalidated block. In situations
such as Shopify/yjit#226, the address to the start of the block
is saved and used later, possibly after the block is invalidated.
The assume_* family of function now generate block->entry_exit before
remembering blocks for invalidation.
RubyVM::YJIT.simulate_oom! is introduced for testing out of memory
conditions. The test for it is disabled for now because OOM triggers
other failure conditions not addressed by this commit.
Fixes Shopify/yjit#226