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Fix -escapes-internal-verify for summary graph merging.

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Don't merge node properties until after node merging begins, so
internal verification can run right before each merge.

Rework ConnectionGraph::mergeFrom. Remove an extra loop. Defer
mergeAllScheduledNodes until all the source graph's mapped nodes are
added so that the graph is always structurally valid before a
merge. This is also necessary to avoid EscapeAnalysis
assert: (!To->mergeTo), in setPointsToEdge.

Enable -escapes-internal-verify to all tests in escape_analysis.sil.

Add hand-reduced unit tests in escape_analysis_reduced.sil.
This commit is contained in:
Andrew Trick
2020-01-14 22:17:12 -08:00
parent e50ff0f2b8
commit 9495af6b75
6 changed files with 400 additions and 51 deletions
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89
lib/SILOptimizer/Analysis/EscapeAnalysis.cpp
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@@ -558,7 +558,8 @@ void EscapeAnalysis::ConnectionGraph::initializePointsTo(CGNode *initialNode,
CGNode *predNode = pred.getPredNode();
if (predNode->pointsTo) {
assert(predNode->pointsTo->getMergeTarget() == newPointsTo);
assert(predNode->pointsTo->getMergeTarget()
== newPointsTo->getMergeTarget());
return Traversal::Backtrack;
}
predNode->pointsTo = newPointsTo;
@@ -761,6 +762,11 @@ void EscapeAnalysis::ConnectionGraph::mergePointsTo(CGNode *initialNode,
CGNode *newPointsTo) {
CGNode *oldPointsTo = initialNode->pointsTo;
assert(oldPointsTo && "merging content should not initialize any pointsTo");
// newPointsTo may already be scheduled for a merge. Only create new edges to
// unmerged nodes. This may create a temporary pointsTo mismatch in the defer
// web, but Graph verification takes merged nodes into consideration.
newPointsTo = newPointsTo->getMergeTarget();
if (oldPointsTo == newPointsTo)
return;
@@ -870,8 +876,6 @@ CGNode *EscapeAnalysis::ConnectionGraph::createContentNode(
CGNode *newContent =
allocNode(nullptr, NodeType::Content, isInterior, hasReferenceOnly);
initializePointsToEdge(addrNode, newContent);
assert(ToMerge.empty()
&& "Initially setting pointsTo should not require any node merges");
return newContent;
}
@@ -1002,57 +1006,58 @@ bool EscapeAnalysis::ConnectionGraph::mergeFrom(ConnectionGraph *SourceGraph,
CGNodeMap &Mapping) {
// The main point of the merging algorithm is to map each content node in the
// source graph to a content node in this (destination) graph. This may
// require to create new nodes or to merge existing nodes in this graph.
// require creating new nodes or merging existing nodes in this graph.
// First step: replicate the points-to edges and the content nodes of the
// source graph in this graph.
bool Changed = false;
bool NodesMerged;
do {
NodesMerged = false;
for (unsigned Idx = 0; Idx < Mapping.getMappedNodes().size(); ++Idx) {
CGNode *SourceNd = Mapping.getMappedNodes()[Idx];
CGNode *DestNd = Mapping.get(SourceNd);
assert(DestNd);
if (SourceNd->getEscapeState() >= EscapeState::Global) {
// We don't need to merge the source subgraph of nodes which have the
// global escaping state set.
// Just set global escaping in the caller node and that's it.
Changed |= DestNd->mergeEscapeState(EscapeState::Global);
// If DestNd is an interior node, its content still needs to be created.
if (!DestNd->isInterior())
continue;
}
for (unsigned Idx = 0; Idx < Mapping.getMappedNodes().size(); ++Idx) {
CGNode *SourceNd = Mapping.getMappedNodes()[Idx];
CGNode *DestNd = Mapping.get(SourceNd);
assert(DestNd);
CGNode *SourcePT = SourceNd->pointsTo;
if (!SourcePT)
if (SourceNd->getEscapeState() >= EscapeState::Global) {
// We don't need to merge the source subgraph of nodes which have the
// global escaping state set.
// Just set global escaping in the caller node and that's it.
Changed |= DestNd->mergeEscapeState(EscapeState::Global);
// If DestNd is an interior node, its content still needs to be created.
if (!DestNd->isInterior())
continue;
}
CGNode *DestPT = DestNd->pointsTo;
CGNode *SourcePT = SourceNd->pointsTo;
if (!SourcePT)
continue;
CGNode *MappedDestPT = Mapping.get(SourcePT);
CGNode *DestPT = DestNd->pointsTo;
if (!MappedDestPT) {
if (!DestPT) {
DestPT = createMergedContent(DestNd, SourcePT);
Changed = true;
}
CGNode *MappedDestPT = Mapping.get(SourcePT);
if (!MappedDestPT) {
// This is the first time the dest node is seen; just add the mapping.
Mapping.add(SourcePT, DestPT);
continue;
}
// We already found the destination node through another path.
assert(Mapping.getMappedNodes().contains(SourcePT));
if (DestPT == MappedDestPT)
continue;
// There are two content nodes in this graph which map to the same
// content node in the source graph -> we have to merge them.
scheduleToMerge(DestPT, MappedDestPT);
mergeAllScheduledNodes();
Changed = true;
NodesMerged = true;
// This is the first time the dest node is seen; just add the mapping.
Mapping.add(SourcePT, DestPT);
continue;
}
} while (NodesMerged);
if (DestPT == MappedDestPT)
continue;
// We already found the destination node through another path.
assert(Mapping.getMappedNodes().contains(SourcePT));
Changed = true;
if (!DestPT) {
initializePointsToEdge(DestNd, MappedDestPT);
continue;
}
// There are two content nodes in this graph which map to the same
// content node in the source graph -> we have to merge them.
// Defer merging the nodes until all mapped nodes are created so that the
// graph is structurally valid before merging.
scheduleToMerge(DestPT, MappedDestPT);
}
mergeAllScheduledNodes();
Mapping.getMappedNodes().reset(); // Make way for a different worklist.
// Second step: add the source graph's defer edges to this graph.