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refactor two swift passes #65821

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Merged
merged 1 commit into from
May 10, 2023
Merged

refactor two swift passes #65821

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114 changes: 57 additions & 57 deletions SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,7 @@ let initializeStaticGlobalsPass = FunctionPass(name: "initialize-static-globals"
return
}

guard let (allocInst, storeToGlobal) = function.getGlobalInitialization() else {
guard let (allocInst, storeToGlobal) = getGlobalInitialization(of: function) else {
return
}

Expand All @@ -62,69 +62,69 @@ let initializeStaticGlobalsPass = FunctionPass(name: "initialize-static-globals"
context.erase(instruction: storeToGlobal)
}

private extension Function {
/// Analyses the global initializer function and returns the `alloc_global` and `store`
/// instructions which initialize the global.
///
/// The function's single basic block must contain following code pattern:
/// ```
/// alloc_global @the_global
/// %a = global_addr @the_global
/// %i = some_const_initializer_insts
/// store %i to %a
/// ```
func getGlobalInitialization() -> (allocInst: AllocGlobalInst, storeToGlobal: StoreInst)? {
/// Analyses the global initializer function and returns the `alloc_global` and `store`
/// instructions which initialize the global.
///
/// The function's single basic block must contain following code pattern:
/// ```
/// alloc_global @the_global
/// %a = global_addr @the_global
/// %i = some_const_initializer_insts
/// store %i to %a
/// ```
private func getGlobalInitialization(of function: Function) -> (allocInst: AllocGlobalInst, storeToGlobal: StoreInst)? {

guard let block = singleBlock else {
return nil
}
guard let block = function.singleBlock else {
return nil
}

var allocInst: AllocGlobalInst? = nil
var globalAddr: GlobalAddrInst? = nil
var store: StoreInst? = nil
var allocInst: AllocGlobalInst? = nil
var globalAddr: GlobalAddrInst? = nil
var store: StoreInst? = nil

for inst in block.instructions {
switch inst {
case is ReturnInst,
is DebugValueInst,
is DebugStepInst:
break
case let agi as AllocGlobalInst:
if allocInst != nil {
return nil
}
allocInst = agi
case let ga as GlobalAddrInst:
if globalAddr != nil {
return nil
}
guard let agi = allocInst, agi.global == ga.global else {
return nil
}
globalAddr = ga
case let si as StoreInst:
if store != nil {
return nil
}
guard let ga = globalAddr else {
return nil
}
if si.destination != ga {
return nil
}
store = si
default:
if !inst.isValidInStaticInitializerOfGlobal {
return nil
}
for inst in block.instructions {
switch inst {
case is ReturnInst,
is DebugValueInst,
is DebugStepInst:
break
case let agi as AllocGlobalInst:
if allocInst != nil {
return nil
}
allocInst = agi
case let ga as GlobalAddrInst:
if globalAddr != nil {
return nil
}
guard let agi = allocInst, agi.global == ga.global else {
return nil
}
globalAddr = ga
case let si as StoreInst:
if store != nil {
return nil
}
guard let ga = globalAddr else {
return nil
}
if si.destination != ga {
return nil
}
store = si
default:
if !inst.isValidInStaticInitializerOfGlobal {
return nil
}
}
if let store = store {
return (allocInst: allocInst!, storeToGlobal: store)
}
return nil
}
if let store = store {
return (allocInst: allocInst!, storeToGlobal: store)
}
return nil
}

private extension Function {
var singleBlock: BasicBlock? {
let block = entryBlock
if block.next != nil {
Expand Down
10 changes: 4 additions & 6 deletions SwiftCompilerSources/Sources/Optimizer/ModulePasses/ReadOnlyGlobalVariables.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ let readOnlyGlobalVariablesPass = ModulePass(name: "read-only-global-variables")
for f in moduleContext.functions {
for inst in f.instructions {
if let gAddr = inst as? GlobalAddrInst {
if gAddr.addressHasWrites {
if findWrites(toAddress: gAddr) {
writtenGlobals.insert(gAddr.global)
}
}
Expand All @@ -43,11 +43,9 @@ let readOnlyGlobalVariablesPass = ModulePass(name: "read-only-global-variables")
}
}

private extension Value {
var addressHasWrites: Bool {
var walker = FindWrites()
return walker.walkDownUses(ofAddress: self, path: UnusedWalkingPath()) == .abortWalk
}
private func findWrites(toAddress: Value) -> Bool {
var walker = FindWrites()
return walker.walkDownUses(ofAddress: toAddress, path: UnusedWalkingPath()) == .abortWalk
}

private struct FindWrites : AddressDefUseWalker {
Expand Down