Don't move objc_autorelease calls past autorelease pool boundaries when
optimizing autorelease calls on phi nodes with null operands.
This fixes rdar://11207070.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154642 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
index 56e6c4c..62c4694 100644
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/lib/Transforms/Scalar/ObjCARC.cpp
@@ -1963,6 +1963,7 @@
/// use here.
enum DependenceKind {
NeedsPositiveRetainCount,
+ AutoreleasePoolBoundary,
CanChangeRetainCount,
RetainAutoreleaseDep, ///< Blocks objc_retainAutorelease.
RetainAutoreleaseRVDep, ///< Blocks objc_retainAutoreleaseReturnValue.
@@ -1992,6 +1993,19 @@
}
}
+ case AutoreleasePoolBoundary: {
+ InstructionClass Class = GetInstructionClass(Inst);
+ switch (Class) {
+ case IC_AutoreleasepoolPop:
+ case IC_AutoreleasepoolPush:
+ // These mark the end and begin of an autorelease pool scope.
+ return true;
+ default:
+ // Nothing else does this.
+ return false;
+ }
+ }
+
case CanChangeRetainCount: {
InstructionClass Class = GetInstructionClass(Inst);
switch (Class) {
@@ -2009,6 +2023,7 @@
case RetainAutoreleaseDep:
switch (GetBasicInstructionClass(Inst)) {
case IC_AutoreleasepoolPop:
+ case IC_AutoreleasepoolPush:
// Don't merge an objc_autorelease with an objc_retain inside a different
// autoreleasepool scope.
return true;
@@ -2376,9 +2391,34 @@
// Check that there is nothing that cares about the reference
// count between the call and the phi.
- FindDependencies(NeedsPositiveRetainCount, Arg,
- Inst->getParent(), Inst,
- DependingInstructions, Visited, PA);
+ switch (Class) {
+ case IC_Retain:
+ case IC_RetainBlock:
+ // These can always be moved up.
+ break;
+ case IC_Release:
+ // These can't be moved across things that care about the retain count.
+ FindDependencies(NeedsPositiveRetainCount, Arg,
+ Inst->getParent(), Inst,
+ DependingInstructions, Visited, PA);
+ break;
+ case IC_Autorelease:
+ // These can't be moved across autorelease pool scope boundaries.
+ FindDependencies(AutoreleasePoolBoundary, Arg,
+ Inst->getParent(), Inst,
+ DependingInstructions, Visited, PA);
+ break;
+ case IC_RetainRV:
+ case IC_AutoreleaseRV:
+ // Don't move these; the RV optimization depends on the autoreleaseRV
+ // being tail called, and the retainRV being immediately after a call
+ // (which might still happen if we get lucky with codegen layout, but
+ // it's not worth taking the chance).
+ continue;
+ default:
+ llvm_unreachable("Invalid dependence flavor");
+ }
+
if (DependingInstructions.size() == 1 &&
*DependingInstructions.begin() == PN) {
Changed = true;