47 строки
1,2 КиБ
Go
47 строки
1,2 КиБ
Go
package transform
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import (
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"tinygo.org/x/go-llvm"
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)
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// OptimizeMaps eliminates created but unused maps.
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//
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// In the future, this should statically allocate created but never modified
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// maps. This has not yet been implemented, however.
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func OptimizeMaps(mod llvm.Module) {
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hashmapMake := mod.NamedFunction("runtime.hashmapMake")
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if hashmapMake.IsNil() {
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// nothing to optimize
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return
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}
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hashmapBinarySet := mod.NamedFunction("runtime.hashmapBinarySet")
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hashmapStringSet := mod.NamedFunction("runtime.hashmapStringSet")
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for _, makeInst := range getUses(hashmapMake) {
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updateInsts := []llvm.Value{}
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unknownUses := false // are there any uses other than setting a value?
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for _, use := range getUses(makeInst) {
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if use := use.IsACallInst(); !use.IsNil() {
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switch use.CalledValue() {
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case hashmapBinarySet, hashmapStringSet:
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updateInsts = append(updateInsts, use)
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default:
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unknownUses = true
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}
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} else {
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unknownUses = true
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}
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}
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if !unknownUses {
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// This map can be entirely removed, as it is only created but never
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// used.
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for _, inst := range updateInsts {
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inst.EraseFromParentAsInstruction()
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}
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makeInst.EraseFromParentAsInstruction()
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}
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}
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}
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