Rework br_table to use BlockCall, allowing us to avoid adding new nodes during ssa construction to hold block arguments. Additionally, many places where we previously matched on InstructionData to extract branch destinations can be replaced with a use of branch_destination or branch_destination_mut.
Add a conditional branch instruction with two targets: brif. This instruction will eventually replace brz and brnz, as it encompasses the behavior of both.
This PR also changes the InstructionData layout for instruction formats that hold BlockCall values, taking the same approach we use for Value arguments. This allows branch_destination to return a slice to the BlockCall values held in the instruction, rather than requiring that we pattern match on InstructionData to fetch the then/else blocks.
Function generation for fuzzing has been updated to generate uses of brif, and I've run the cranelift-fuzzgen target locally for hours without triggering any new failures.
Add a new type BlockCall that represents the pair of a block name with arguments to be passed to it. (The mnemonic here is that it looks a bit like a function call.) Rework the implementation of jump, brz, and brnz to use BlockCall instead of storing the block arguments as varargs in the instruction's ValueList.
To ensure that we're processing block arguments from BlockCall values in instructions, three new functions have been introduced on DataFlowGraph that both sets of arguments:
inst_values - returns an iterator that traverses values in the instruction and block arguments
map_inst_values - applies a function to each value in the instruction and block arguments
overwrite_inst_values - overwrite all values in an instruction and block arguments with values from the iterator
Co-authored-by: Jamey Sharp <jamey@minilop.net>
We have some operations defined on DataFlowGraph purely to work around borrow-checker issues with InstructionData and other data on DataFlowGraph. Part of the problem is that indexing the DFG directly hides the fact that we're only indexing the insts field of the DFG.
This PR makes the insts field of the DFG public, but wraps it in a newtype that only allows indexing. This means that the borrow checker is better able to tell when operations on memory held by the DFG won't conflict, which comes up frequently when mutating ValueLists held by InstructionData.
* Cranelift: Use bump allocation in `remove_constant_phis` pass
This makes compilation 2-6% faster for Sightglass's bz2 benchmark:
```
compilation :: cycles :: benchmarks/bz2/benchmark.wasm
Δ = 7290648.36 ± 4245152.07 (confidence = 99%)
bump.so is 1.02x to 1.06x faster than main.so!
[166388177 183238542.98 214732518] bump.so
[172836648 190529191.34 217514271] main.so
compilation :: cycles :: benchmarks/pulldown-cmark/benchmark.wasm
No difference in performance.
[182220055 225793551.12 277857575] bump.so
[193212613 227784078.61 277175335] main.so
compilation :: cycles :: benchmarks/spidermonkey/benchmark.wasm
No difference in performance.
[3848442474 4295214144.37 4665127241] bump.so
[3969505457 4262415290.10 4563869974] main.so
```
* Add audit for `bumpalo`
* Add an audit of `arrayvec` version 0.7.2
* Remove unnecessary `collect` into `Vec`
I wasn't able to measure any perf difference here, but its nice to do anyways.
* Use a `SecondaryMap` for keeping track of summaries
that only one value ever flows. Has been observed to improve generated code
run times by up to 8%. Compilation cost increases by about 0.6%, but up to 7%
total cost has been observed to be saved; iow it can be a significant win in
terms of compilation time, overall.
