gh-106529: Implement POP_JUMP_IF_XXX uops #106551
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This adds:
- Hand-written uops JUMP_IF_{TRUE,FALSE,NONE,NOT_NONE}.
These peek at the top of the stack.
The jump target (in superblock space) is absolute.
- Hand-written translation for POP_JUMP_IF_TRUE,
assuming the jump is unlikely.
This can serve as an example for the rest.
(Probably adding the others will cause a little refactoring.)
Once we implement jump-likelihood profiling,
we can implement the jump-unlikely case.
Note that the stubs are placed at the end of the trace array.
There is a gap between the main superblock and the stubs.
We could close the gap, we'd just have to patch up the JUMP uops.
11 tasks
Also include them in the returned trace length.
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Since we discussed this extensively off-line, I'm going to just merge this once all tests pass. |
This required improving len(ex) and ex[i] a bit. There is now a sentinel opcode (0) at the end, *unless* the trace array is full.
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This adds:
Hand-written uops
_POP_JUMP_IF_{TRUE,FALSE}. These pop the top of the stack. The jump target (in superblock space) is absolute.Hand-written translation for
POP_JUMP_IF_{TRUE,FALSE}, assuming the jump is unlikely. Once we implement jump-likelihood profiling, we can implement the jump-unlikely case.Note that the stubs are placed at the end of the trace array (and not counted in the return value of translate_bytecode_to_trace(), which is a bid dodgy). There is a gap between the main superblock and the stubs. We could close the gap, we'd just have to patch up the JUMP uops.
TODO in this PR:
TODO in a follow-up PR: