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[g-arc-opts] Perform same refactoring for top down analysis as I performed for bottom up analysis in r26901.

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Swift SVN r26906
This commit is contained in:
Michael Gottesman
2015-04-02 22:07:28 +00:00
parent 5c8fde3f2e
commit 9b77fe1cb1
4 changed files with 141 additions and 74 deletions
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88
lib/SILAnalysis/GlobalARCSequenceDataflow.cpp
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@@ -24,7 +24,6 @@
#include "swift/SIL/SILModule.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/Debug.h"
using namespace swift;
@@ -33,21 +32,6 @@ using namespace swift;
// Utilities
//===----------------------------------------------------------------------===//
static bool isAutoreleasePoolCall(SILInstruction &I) {
ApplyInst *AI = dyn_cast<ApplyInst>(&I);
if (!AI)
return false;
FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(AI->getCallee());
if (!FRI)
return false;
return llvm::StringSwitch<bool>(FRI->getReferencedFunction()->getName())
.Case("objc_autoreleasePoolPush", true)
.Case("objc_autoreleasePoolPop", true)
.Default(false);
}
namespace {
using ARCBBState = ARCSequenceDataflowEvaluator::ARCBBState;
@@ -102,72 +86,28 @@ static bool processBBTopDown(
}
}
TopDownDataflowRCStateVisitor DataflowVisitor(RCIA, BBState,
DecToIncStateMap);
// For each instruction I in BB...
for (auto &I : BB) {
DEBUG(llvm::dbgs() << "VISITING:\n " << I);
// If we see an autorelease pool call, be conservative and clear all state
// that we are currently tracking in the BB.
if (isAutoreleasePoolCall(I)) {
BBState.clear();
auto Result = DataflowVisitor.visit(&I);
// If this instruction can have no further effects on another instructions,
// continue. This happens for instance if we have cleared all of the state
// we are tracking.
if (Result.Kind == RCStateTransitionDataflowResultKind::NoEffects)
continue;
}
SILValue Op;
RCStateTransitionKind TransitionKind = getRCStateTransitionKind(&I);
// Make sure that we propagate out whether or not nesting was detected.
NestingDetected |= Result.NestingDetected;
// If I is a ref count increment instruction...
if (TransitionKind == RCStateTransitionKind::StrongIncrement) {
// map its operand to a newly initialized or reinitialized ref count
// state and continue...
Op = RCIA->getRCIdentityRoot(I.getOperand(0));
TopDownRefCountState &State = BBState.getTopDownRefCountState(Op);
NestingDetected |= State.initWithInst(&I);
DEBUG(llvm::dbgs() << " REF COUNT INCREMENT! Known Safe: "
<< (State.isKnownSafe() ? "yes" : "no") << "\n");
// Continue processing in case this increment could be a CanUse for a
// different pointer.
}
// If we have a reference count decrement...
if (TransitionKind == RCStateTransitionKind::StrongDecrement) {
// Look up the state associated with its operand...
Op = RCIA->getRCIdentityRoot(I.getOperand(0));
TopDownRefCountState &RefCountState = BBState.getTopDownRefCountState(Op);
DEBUG(llvm::dbgs() << " REF COUNT DECREMENT!\n");
// If we are tracking an increment on the ref count root associated with
// the decrement and the decrement matches, pair this decrement with a
// copy of the increment state and then clear the original increment state
// so that we are ready to process further values.
if (RefCountState.isRefCountInstMatchedToTrackedInstruction(&I)) {
// Copy the current value of ref count state into the result map.
DecToIncStateMap[&I] = RefCountState;
DEBUG(llvm::dbgs() << " MATCHING INCREMENT:\n"
<< RefCountState.getRCRoot());
// Clear the ref count state in preparation for more pairs.
RefCountState.clear();
}
#if NDEBUG
else {
if (RefCountState.isTrackingRefCountInst()) {
DEBUG(llvm::dbgs() << " FAILED MATCH INCREMENT:\n"
<< RefCountState.getValue());
} else {
DEBUG(llvm::dbgs() << " FAILED MATCH. NO INCREMENT.\n");
}
}
#endif
// Otherwise we continue processing the reference count decrement to
// see if the decrement can affect any other pointers that we are
// tracking.
}
// This SILValue may be null if we were unable to find a specific RCIdentity
// that the instruction "visits".
SILValue Op = Result.RCIdentity;
// For all other [(SILValue, TopDownState)] we are tracking...
for (auto &OtherState : BBState.getTopDownStates()) {