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Consider moving semantic actions to functions, leave inlining decisions to LLVM/rustc #8

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osa1 opened this issue Jun 4, 2021 · 2 comments · Fixed by #19
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Consider moving semantic actions to functions, leave inlining decisions to LLVM/rustc #8

osa1 opened this issue Jun 4, 2021 · 2 comments · Fixed by #19
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code size Related to generated code size perf Related to runtime performance

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osa1 commented Jun 4, 2021

With #7 we now generate much more efficient code, but in principle it could lead to code size explosion when some semantic actions have large code and lots of incoming edges in the DFA. I didn't see this happen in practice yet, but I think it could happen.

If we introduce a top-level function for semantic actions, then duplicated code will just be a call expression to the semantic action function. Inlining the semantic action code is then left to LLVM/rustc. I think this would give us more or less the same result for small semantic actions and avoid code size blowup in the worst case.
@osa1 osa1 added perf Related to runtime performance code size Related to generated code size labels Jun 4, 2021
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osa1 commented Oct 12, 2021

We could also add a syntax (maybe reuse Rust attribute syntax) to force inlining a RHS.

@osa1 osa1 mentioned this issue Oct 18, 2021
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osa1 commented Oct 18, 2021

This is blocking #16.

osa1 added a commit that referenced this issue Oct 19, 2021
@osa1
Start generating semantic actions as fns (#8)
c1da595
osa1 added a commit that referenced this issue Oct 19, 2021
@osa1
Fixing errors (#8)
fa4a3e6
osa1 added a commit that referenced this issue Oct 19, 2021
@osa1
Fix #11 again (#8)
cfc480f
osa1 added a commit that referenced this issue Oct 19, 2021
@osa1
Fix some lints (#8)
5c815e2
osa1 added a commit that referenced this issue Oct 19, 2021
@osa1
Fix a few bugs (#8)
9170191
@osa1 osa1 mentioned this issue Oct 19, 2021
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@osa1 osa1 closed this as completed in #19 Oct 19, 2021
osa1 added a commit that referenced this issue Oct 19, 2021
@osa1
Generate functions for semantic actions (#19)
5c2447c 
- To be able to implement backtracking in #16 we need to store semantic action
  of the last accepting state we've seen. For that we need functions for
  semantic actions.

- DFA simplification duplicates semantic actions, having functions for semantic
  actions means we leave inlining decisions to the compiler (fixes #8).
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Generate functions for semantic actions osa1/lexgen
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