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2021-12-01YJIT: Fail gracefully while OOM for new entry pointsAlan Wu
Previously, YJIT crashes with rb_bug() when asked to compile new methods while out of executable memory. To handle this situation gracefully, this change keeps track of all the blocks compiled each invocation in case YJIT runs out of memory in the middle of a compliation sequence. The list is used to free all blocks in case compilation fails. yjit_gen_block() is renamed to gen_single_block() to make it distinct from gen_block_version(). Call to limit_block_version() and block_t allocation is moved into the function to help tidy error checking in the outer loop. limit_block_version() now returns by value. I feel that an out parameter with conditional mutation is unnecessarily hard to read in code that does not need to go for last drop performance. There is a good chance that the optimizer is able to output identical code anyways. Notes: Merged: https://github.com/ruby/ruby/pull/5191
2021-11-26YJIT: Add ability to exit to interpreter from stubsAlan Wu
Previously, YJIT assumed that it's always possible to generate a new basic block when servicing a stub in branch_stub_hit(). When YJIT is out of executable memory, for example, this assumption doesn't hold up. Add handling to branch_stub_hit() for servicing stubs without consuming more executable memory by adding a code path that exits to the interpreter at the location the branch stub represents. The new code path reconstructs interpreter state in branch_stub_hit() and then exits with a new snippet called `code_for_exit_from_stub` that returns `Qundef` from the YJIT native stack frame. As this change adds another place where we regenerate code from `branch_t`, extract the logic for it into a new function and call it regenerate_branch(). While we are at it, make the branch shrinking code path in branch_stub_hit() more explicit. This new functionality is hard to test without full support for out of memory conditions. To verify this change, I ran `RUBY_YJIT_ENABLE=1 make check -j12` with the following patch to stress test the new code path: ```diff diff --git a/yjit_core.c b/yjit_core.c index 4ab63d9806..5788b8c5ed 100644 --- a/yjit_core.c +++ b/yjit_core.c @@ -878,8 +878,12 @@ branch_stub_hit(branch_t *branch, const uint32_t target_idx, rb_execution_contex cb_set_write_ptr(cb, branch->end_addr); } +if (rand() < RAND_MAX/2) { // Compile the new block version p_block = gen_block_version(target, target_ctx, ec); +}else{ + p_block = NULL; +} if (!p_block && branch_modified) { // We couldn't generate a new block for the branch, but we modified the branch. ``` We can enable the new test along with other OOM tests once full support lands. Other small changes: * yjit_utils.c (print_str): Update to work with new native frame shape. Follow up for 8fa0ee4d404. * yjit_iface.c (rb_yjit_init): Run yjit_init_core() after yjit_init_codegen() so `cb` and `ocb` are available. Notes: Merged: https://github.com/ruby/ruby/pull/5180 Merged-By: XrXr
2021-11-22YJIT: Make block invalidation more robustAlan Wu
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 Notes: Merged: https://github.com/ruby/ruby/pull/5145
2021-10-20Put YJIT into a single compilation unitAlan Wu
For upstreaming, we want functions we export either prefixed with "rb_" or made static. Historically we haven't been following this rule, so we were "leaking" a lot of symbols as `make leak-globals` would tell us. This change unifies everything YJIT into a single compilation unit, yjit.o, and makes everything unprefixed static to pass `make leak-globals`. This manual "unified build" setup is similar to that of vm.o. Having everything in one compilation unit allows static functions to be visible across YJIT files and removes the need for declarations in headers in some cases. Unnecessary declarations were removed. Other changes of note: - switched to MJIT_SYMBOL_EXPORT_BEGIN which indicates stuff as being off limits for native extensions - the first include of each YJIT file is change to be "internal.h" - undefined MAP_STACK before explicitly redefining it since it collide's with a definition in system headers. Consider renaming?
2021-10-20style: align pointer "*" to the rightAlan Wu
2021-10-20Remove a few more uses of the global cb/ocbMaxime Chevalier-Boisvert
2021-10-20Step 2 to remove the global cb/ocb objects.Maxime Chevalier-Boisvert
2021-10-20Pass the global cb through codegen functionsMaxime Chevalier-Boisvert
2021-10-20Deduplicate side exitsAlan Wu
Send instructions currently generate the exact same side exit twice. Cache the exit the first time we generate it. Also add a comment explaining what side exits do. Closes GH-117.
2021-10-20typo, rename, commentAlan Wu
2021-10-20TracePoint supportAlan Wu
This change fixes some cases where YJIT fails to fire tracing events. Most of the situations YJIT did not handle correctly involves enabling tracing while running inside generated code. A new operation to invalidate all generated code is added, which uses patching to make generated code exit at the next VM instruction boundary. A new routine called `jit_prepare_routine_call()` is introduced to facilitate this and should be used when generating code that could allocate, or could otherwise use `RB_VM_LOCK_ENTER()`. The `c_return` event is fired in the middle of an instruction as opposed to at an instruction boundary, so it requires special handling. C method call return points are patched to go to a fucntion which does everything the interpreter does, including firing the `c_return` event. The generated code for C method calls normally does not fire the event. Invalided code should not change after patching so the exits are not clobbered. A new variable is introduced to track the region of code that should not change.
2021-10-20Add a guard that we start executing on the first PCAaron Patterson
Methods with optional parameters don't always start executing at the first PC, but we compile all methods assuming that they do. This commit adds a guard to ensure that we're actually starting at the first PC for methods with optional params
2021-10-20Implement send with blocksAlan Wu
* Implement send with blocks Not that much extra work compared to `opt_send_without_block`. Moved the stack over flow check because it could've exited after changes are made to cfp. * rename oswb counters * Might as well implement sending block to cfuncs * Disable sending blocks to cfuncs for now * Reconstruct interpreter sp before calling into cfuncs In case the callee cfunc calls a method or delegates to a block. This also has the side benefit of letting call sites that sometimes are iseq calls and sometimes cfunc call share the same successor. * only sync with interpreter sp when passing a block Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com> Co-authored-by: Aaron Patterson <aaron.patterson@shopify.com>
2021-10-20Implement greedy versioning. Refactor versioning logic. (#10)Maxime Chevalier-Boisvert
* Implement eager versioning. Refactor versioning logic. * Add --version-limit and --greedy-versioning command-line args
2021-10-20Yet Another Ruby JIT!Jose Narvaez
Renaming uJIT to YJIT. AKA s/ujit/yjit/g.