Fix integer overflow in instruction scheduling. This can happen if we have
basic blocks that are so long that their size overflows a short.
Also assert that overflow does not happen in the future, as requested by Evan.
This fixes PR4401.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83159 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PostRASchedulerList.cpp b/lib/CodeGen/PostRASchedulerList.cpp
index 42954ea..5fa598d 100644
--- a/lib/CodeGen/PostRASchedulerList.cpp
+++ b/lib/CodeGen/PostRASchedulerList.cpp
@@ -972,17 +972,17 @@
/// the PendingQueue if the count reaches zero. Also update its cycle bound.
void SchedulePostRATDList::ReleaseSucc(SUnit *SU, SDep *SuccEdge) {
SUnit *SuccSU = SuccEdge->getSUnit();
- --SuccSU->NumPredsLeft;
-
+
#ifndef NDEBUG
- if (SuccSU->NumPredsLeft < 0) {
+ if (SuccSU->NumPredsLeft == 0) {
errs() << "*** Scheduling failed! ***\n";
SuccSU->dump(this);
errs() << " has been released too many times!\n";
llvm_unreachable(0);
}
#endif
-
+ --SuccSU->NumPredsLeft;
+
// Compute how many cycles it will be before this actually becomes
// available. This is the max of the start time of all predecessors plus
// their latencies.
diff --git a/lib/CodeGen/ScheduleDAG.cpp b/lib/CodeGen/ScheduleDAG.cpp
index ff5c236..5a59862 100644
--- a/lib/CodeGen/ScheduleDAG.cpp
+++ b/lib/CodeGen/ScheduleDAG.cpp
@@ -82,13 +82,19 @@
SUnit *N = D.getSUnit();
// Update the bookkeeping.
if (D.getKind() == SDep::Data) {
+ assert(NumPreds < UINT_MAX && "NumPreds will overflow!");
+ assert(N->NumSuccs < UINT_MAX && "NumSuccs will overflow!");
++NumPreds;
++N->NumSuccs;
}
- if (!N->isScheduled)
+ if (!N->isScheduled) {
+ assert(NumPredsLeft < UINT_MAX && "NumPredsLeft will overflow!");
++NumPredsLeft;
- if (!isScheduled)
+ }
+ if (!isScheduled) {
+ assert(N->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!");
++N->NumSuccsLeft;
+ }
Preds.push_back(D);
N->Succs.push_back(P);
if (P.getLatency() != 0) {
@@ -121,13 +127,19 @@
Preds.erase(I);
// Update the bookkeeping.
if (P.getKind() == SDep::Data) {
+ assert(NumPreds > 0 && "NumPreds will underflow!");
+ assert(N->NumSuccs > 0 && "NumSuccs will underflow!");
--NumPreds;
--N->NumSuccs;
}
- if (!N->isScheduled)
+ if (!N->isScheduled) {
+ assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!");
--NumPredsLeft;
- if (!isScheduled)
+ }
+ if (!isScheduled) {
+ assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!");
--N->NumSuccsLeft;
+ }
if (P.getLatency() != 0) {
this->setDepthDirty();
N->setHeightDirty();
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
index d1930b1..7eac4d8 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
@@ -134,17 +134,17 @@
/// the AvailableQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGFast::ReleasePred(SUnit *SU, SDep *PredEdge) {
SUnit *PredSU = PredEdge->getSUnit();
- --PredSU->NumSuccsLeft;
-
+
#ifndef NDEBUG
- if (PredSU->NumSuccsLeft < 0) {
+ if (PredSU->NumSuccsLeft == 0) {
errs() << "*** Scheduling failed! ***\n";
PredSU->dump(this);
errs() << " has been released too many times!\n";
llvm_unreachable(0);
}
#endif
-
+ --PredSU->NumSuccsLeft;
+
// If all the node's successors are scheduled, this node is ready
// to be scheduled. Ignore the special EntrySU node.
if (PredSU->NumSuccsLeft == 0 && PredSU != &EntrySU) {
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
index 628a2a87..f17fe23 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
@@ -108,17 +108,17 @@
/// the PendingQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGList::ReleaseSucc(SUnit *SU, const SDep &D) {
SUnit *SuccSU = D.getSUnit();
- --SuccSU->NumPredsLeft;
-
+
#ifndef NDEBUG
- if (SuccSU->NumPredsLeft < 0) {
+ if (SuccSU->NumPredsLeft == 0) {
errs() << "*** Scheduling failed! ***\n";
SuccSU->dump(this);
errs() << " has been released too many times!\n";
llvm_unreachable(0);
}
#endif
-
+ --SuccSU->NumPredsLeft;
+
SuccSU->setDepthToAtLeast(SU->getDepth() + D.getLatency());
// If all the node's predecessors are scheduled, this node is ready
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index a9d1878..bd6e048 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -278,6 +278,7 @@
AvailableQueue->remove(PredSU);
}
+ assert(PredSU->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!");
++PredSU->NumSuccsLeft;
}
@@ -824,17 +825,17 @@
/// the AvailableQueue if the count reaches zero. Also update its cycle bound.
void ScheduleDAGRRList::ReleaseSucc(SUnit *SU, const SDep *SuccEdge) {
SUnit *SuccSU = SuccEdge->getSUnit();
- --SuccSU->NumPredsLeft;
-
+
#ifndef NDEBUG
- if (SuccSU->NumPredsLeft < 0) {
+ if (SuccSU->NumPredsLeft == 0) {
errs() << "*** Scheduling failed! ***\n";
SuccSU->dump(this);
errs() << " has been released too many times!\n";
llvm_unreachable(0);
}
#endif
-
+ --SuccSU->NumPredsLeft;
+
// If all the node's predecessors are scheduled, this node is ready
// to be scheduled. Ignore the special ExitSU node.
if (SuccSU->NumPredsLeft == 0 && SuccSU != &ExitSU) {