[PH] Replace uses of AssertingVH from members of analysis results with
a lazy-asserting PoisoningVH.
AssertVH is fundamentally incompatible with cache-invalidation of
analysis results. The invaliadtion happens after the AssertingVH has
already fired. Instead, use a PoisoningVH that will assert if the
dangling handle is ever used rather than merely be assigned or
destroyed.
This patch also removes all of the (numerous) doomed attempts to work
around this fundamental incompatibility. It is a pretty significant
simplification IMO.
The most interesting change is in the Inliner where we still do some
clearing because we don't want to rely on the coarse grained
invalidation strategy of the containing pass manager. However, I prefer
the approach that contains this logic to the cleanup phase of the
Inliner, and I think we could enhance the CGSCC analysis management
layer to make this even better in the future if desired.
The rest is straight cleanup.
I've also added a test for one of the harder cases to work around: when
a *module analysis* contains many AssertingVHes pointing at functions.
Differential Revision: https://reviews.llvm.org/D29006
llvm-svn: 292928
diff --git a/llvm/lib/Transforms/IPO/Inliner.cpp b/llvm/lib/Transforms/IPO/Inliner.cpp
index e2dc115..767a207 100644
--- a/llvm/lib/Transforms/IPO/Inliner.cpp
+++ b/llvm/lib/Transforms/IPO/Inliner.cpp
@@ -887,11 +887,10 @@
// made dead by this operation on other functions).
Callee.removeDeadConstantUsers();
if (Callee.use_empty()) {
- // Clear all analyses and the body and queue the function itself for
- // deletion when we finish inlining and call graph updates.
+ // Clear the body and queue the function itself for deletion when we
+ // finish inlining and call graph updates.
// Note that after this point, it is an error to do anything other
// than use the callee's address or delete it.
- FAM.clear(Callee);
Callee.dropAllReferences();
assert(find(DeadFunctions, &Callee) == DeadFunctions.end() &&
"Cannot put cause a function to become dead twice!");
@@ -939,8 +938,13 @@
// sets.
for (Function *DeadF : DeadFunctions) {
// Get the necessary information out of the call graph and nuke the
- // function there.
+ // function there. Also, cclear out any cached analyses.
auto &DeadC = *CG.lookupSCC(*CG.lookup(*DeadF));
+ FunctionAnalysisManager &FAM =
+ AM.getResult<FunctionAnalysisManagerCGSCCProxy>(DeadC, CG)
+ .getManager();
+ FAM.clear(*DeadF);
+ AM.clear(DeadC);
auto &DeadRC = DeadC.getOuterRefSCC();
CG.removeDeadFunction(*DeadF);