averello/swift-mirror
1
0
Fork 0
mirror of https://github.com/apple/swift.git synced 2025-12-21 12:14:44 +01:00
Code Issues Packages Projects Releases Wiki Activity

[rc-id] Address Andy's comments to r25339.

Browse Source 
The only substantial change is that I was iterating over instructions to look
for unchecked_enum_data. The only reason really to do that is to stop phase
ordering issues with simplify-cfg, but it is really not necessary.

Swift SVN r25359
This commit is contained in:
Michael Gottesman
2015-02-18 00:14:15 +00:00
parent 77b2e21eb5
commit cdb1ff6152
1 changed files with 21 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
lib/SILAnalysis/RCIdentityAnalysis.cpp
View File

@@ -136,21 +136,6 @@ SILValue RCIdentityAnalysis::stripOneRCIdentityIncomingValue(SILArgument *A,
/// anything.
static llvm::Optional<bool> proveNonPayloadedEnumCase(SILBasicBlock *BB,
SILValue RCIdentity) {
// First iterate through all of the instructions in BB and see if we can find
// an unchecked_enum_data on RCIdentity.
// For each II in BB...
for (auto &II : *BB) {
// If we do not have a UEDI that is applied to RCIdentity, continue.
auto *UEDI = dyn_cast<UncheckedEnumDataInst>(&II);
if (!UEDI || UEDI->getOperand() != RCIdentity)
continue;
// Otherwise, return true if UEDI is extracting a non-payloaded enum case
// and false otherwise.
return !UEDI->getElement()->hasArgumentType();
}
// Then see if BB has one predecessor... if it does not, return None so we
// keep searching up the domtree.
SILBasicBlock *SinglePred = BB->getSinglePredecessor();
@@ -166,7 +151,10 @@ static llvm::Optional<bool> proveNonPayloadedEnumCase(SILBasicBlock *BB,
// Then return true if along the edge from the SEI to BB, RCIdentity has a
// non-payloaded enum value.
return !SEI->getUniqueCaseForDestination(BB)->hasArgumentType();
auto *Decl = SEI->getUniqueCaseForDestination(BB);
if (!Decl)
return None;
return !Decl->hasArgumentType();
}
bool RCIdentityAnalysis::
@@ -185,6 +173,8 @@ findDominatingNonPayloadedEdge(SILBasicBlock *IncomingEdgeBB,
// I think the only way this can happen is if we have a switch_enum of some
// sort with multiple incoming values going into the destination BB. We are
// not interested in handling that case anyways.
//
// FIXME: If we ever split all critical edges, this should be relooked at.
if (IncomingEdgeBB == RCIdentityBB)
return false;
@@ -212,7 +202,7 @@ findDominatingNonPayloadedEdge(SILBasicBlock *IncomingEdgeBB,
return false;
for (auto *Node = DI->getNode(IncomingEdgeBB); Node; Node = Node->getIDom()) {
// Search for uses of RCIdentity in Node->getBB() that will enable us to
// Search for uses of RCIdentity in Node->getBlock() that will enable us to
// know that it has a non-payloaded enum case.
SILBasicBlock *DominatingBB = Node->getBlock();
llvm::Optional<bool> Result =
@@ -285,7 +275,7 @@ stripRCIdentityPreservingArgs(SILValue V, unsigned RecursionDepth) {
// Ok, this is the first time that we have visited this BB. Get the
// SILArgument's incoming values. If we don't have an incoming value for each
// one of our predecessors, just return SILValue().
llvm::SmallVector<SILValue, 8> IncomingValues;
llvm::SmallVector<std::pair<SILBasicBlock *, SILValue>, 8> IncomingValues;
if (!A->getIncomingValues(IncomingValues) || IncomingValues.empty()) {
return SILValue();
}
@@ -295,14 +285,14 @@ stripRCIdentityPreservingArgs(SILValue V, unsigned RecursionDepth) {
// If we only have one incoming value, just return the identity root of that
// incoming value. There can be no loop problems.
if (IVListSize == 1) {
return IncomingValues[0];
return IncomingValues[0].second;
}
// Ok, we have multiple predecessors. First find the first non-payloaded enum.
llvm::SmallVector<SILValue, 8> NoPayloadEnums;
llvm::SmallVector<SILBasicBlock *, 8> NoPayloadEnumBBs;
unsigned i = 0;
for (; i < IVListSize && isNoPayloadEnum(IncomingValues[i]); ++i) {
NoPayloadEnums.push_back(IncomingValues[i]);
for (; i < IVListSize && isNoPayloadEnum(IncomingValues[i].second); ++i) {
NoPayloadEnumBBs.push_back(IncomingValues[i].first);
}
// If we did not find any non-payloaded enum, there is no RC associated with
@@ -310,16 +300,19 @@ stripRCIdentityPreservingArgs(SILValue V, unsigned RecursionDepth) {
if (i == IVListSize)
return SILValue();
SILValue FirstIV = stripOneRCIdentityIncomingValue(A, IncomingValues[i]);
SILValue FirstIV =
stripOneRCIdentityIncomingValue(A, IncomingValues[i].second);
if (!FirstIV)
return SILValue();
while (i < IVListSize) {
SILValue IV = IncomingValues[i++];
SILBasicBlock *IVBB;
SILValue IV;
std::tie(IVBB, IV) = IncomingValues[i++];
// If IV is a no payload enum, we don't care about it. Skip it.
if (isNoPayloadEnum(IV)) {
NoPayloadEnums.push_back(IV);
NoPayloadEnumBBs.push_back(IVBB);
continue;
}
@@ -336,7 +329,7 @@ stripRCIdentityPreservingArgs(SILValue V, unsigned RecursionDepth) {
// enums are equal to FirstIV after just stripping RCIdentical instructions
// (*NOTE* not args). If we have no NonPayloadEnums, then we know that this
// Arg's RCIdentity must be FirstIV.
if (NoPayloadEnums.empty())
if (NoPayloadEnumBBs.empty())
return FirstIV;
// At this point, we know that we have *some* no-payload enums. If FirstIV is
@@ -351,11 +344,8 @@ stripRCIdentityPreservingArgs(SILValue V, unsigned RecursionDepth) {
// Let IVE be the edge for the non-payloaded enum. It is only safe to perform
// this operation when there exists a dominating edge E' of IVE for which
// FirstIV also takes on a non-payloaded enum value.
if (std::any_of(NoPayloadEnums.begin(), NoPayloadEnums.end(),
[&](const SILValue V) -> bool {
auto *BB = V->getParentBB();
if (!BB)
return true;
if (std::any_of(NoPayloadEnumBBs.begin(), NoPayloadEnumBBs.end(),
[&](SILBasicBlock *BB) -> bool {
return !findDominatingNonPayloadedEdge(BB, FirstIV);
}))
return SILValue();