2021-03-06 18:46:56 -05:00
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#ifndef YJIT_CODEGEN_H
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#define YJIT_CODEGEN_H 1
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2020-12-08 16:54:41 -05:00
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2021-03-01 20:43:58 -05:00
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typedef enum codegen_status {
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YJIT_END_BLOCK,
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YJIT_KEEP_COMPILING,
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YJIT_CANT_COMPILE
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} codegen_status_t;
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2021-01-07 17:09:25 -05:00
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2021-03-01 20:43:58 -05:00
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// Code generation function signature
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2021-09-29 14:58:01 -04:00
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typedef codegen_status_t (*codegen_fn)(jitstate_t *jit, ctx_t *ctx, codeblock_t *cb);
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2021-01-07 17:09:25 -05:00
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2021-11-04 12:30:30 -04:00
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static void jit_ensure_block_entry_exit(jitstate_t *jit);
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2021-10-01 18:38:39 -04:00
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static uint8_t *yjit_entry_prologue(codeblock_t *cb, const rb_iseq_t *iseq);
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2020-12-18 13:49:53 -05:00
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2021-11-19 23:44:13 -05:00
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static block_t *gen_single_block(blockid_t blockid, const ctx_t *start_ctx, rb_execution_context_t *ec);
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2020-12-08 16:54:41 -05:00
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YJIT: Add ability to exit to interpreter from stubs
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.
2021-11-26 18:00:42 -05:00
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static void gen_code_for_exit_from_stub(void);
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2021-10-01 18:38:39 -04:00
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static void yjit_init_codegen(void);
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2020-12-08 16:54:41 -05:00
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2021-03-06 18:46:56 -05:00
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#endif // #ifndef YJIT_CODEGEN_H
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