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InstrProf: Use a locally tracked current count in ComputeRegionCounts 

No functional change. This just makes it more obvious that the logic
in ComputeRegionCounts only depends on the counter map and local
state.

llvm-svn: 236370
This commit is contained in:
Justin Bogner 2015-05-02 00:48:27 +00:00
parent 38477db8c4
commit a909abfd29
2 changed files with 35 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
clang/lib/CodeGen/CodeGenPGO.cpp
View File

@ -242,6 +242,9 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
/// next statement, such as at the exit of a loop.
bool RecordNextStmtCount;
/// The count at the current location in the traversal.
uint64_t CurrentCount;
/// The map of statements to count values.
llvm::DenseMap<const Stmt *, uint64_t> &CountMap;
@ -259,14 +262,14 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
void RecordStmtCount(const Stmt *S) {
if (RecordNextStmtCount) {
CountMap[S] = PGO.getCurrentRegionCount();
CountMap[S] = CurrentCount;
RecordNextStmtCount = false;
}
}
/// Set and return the current count.
uint64_t setCount(uint64_t Count) {
PGO.setCurrentRegionCount(Count);
CurrentCount = Count;
return Count;
}
@ -315,7 +318,7 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
RecordStmtCount(S);
if (S->getRetValue())
Visit(S->getRetValue());
PGO.setCurrentRegionUnreachable();
CurrentCount = 0;
RecordNextStmtCount = true;
}
@ -323,13 +326,13 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
RecordStmtCount(E);
if (E->getSubExpr())
Visit(E->getSubExpr());
PGO.setCurrentRegionUnreachable();
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitGotoStmt(const GotoStmt *S) {
RecordStmtCount(S);
PGO.setCurrentRegionUnreachable();
CurrentCount = 0;
RecordNextStmtCount = true;
}
@ -344,30 +347,30 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
void VisitBreakStmt(const BreakStmt *S) {
RecordStmtCount(S);
assert(!BreakContinueStack.empty() && "break not in a loop or switch!");
BreakContinueStack.back().BreakCount += PGO.getCurrentRegionCount();
PGO.setCurrentRegionUnreachable();
BreakContinueStack.back().BreakCount += CurrentCount;
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitContinueStmt(const ContinueStmt *S) {
RecordStmtCount(S);
assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
BreakContinueStack.back().ContinueCount += PGO.getCurrentRegionCount();
PGO.setCurrentRegionUnreachable();
BreakContinueStack.back().ContinueCount += CurrentCount;
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitWhileStmt(const WhileStmt *S) {
RecordStmtCount(S);
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Visit the body region first so the break/continue adjustments can be
// included when visiting the condition.
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = PGO.getCurrentRegionCount();
CountMap[S->getBody()] = CurrentCount;
Visit(S->getBody());
uint64_t BackedgeCount = PGO.getCurrentRegionCount();
uint64_t BackedgeCount = CurrentCount;
// ...then go back and propagate counts through the condition. The count
// at the start of the condition is the sum of the incoming edges,
@ -388,10 +391,10 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
BreakContinueStack.push_back(BreakContinue());
// The count doesn't include the fallthrough from the parent scope. Add it.
uint64_t BodyCount = setCount(LoopCount + PGO.getCurrentRegionCount());
uint64_t BodyCount = setCount(LoopCount + CurrentCount);
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = PGO.getCurrentRegionCount();
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
// The count at the start of the condition is equal to the count at the
@ -408,7 +411,7 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
if (S->getInit())
Visit(S->getInit());
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Visit the body region first. (This is basically the same as a while
@ -416,7 +419,7 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = PGO.getCurrentRegionCount();
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
// The increment is essentially part of the body but it needs to include
@ -444,15 +447,14 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
Visit(S->getRangeStmt());
Visit(S->getBeginEndStmt());
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Visit the body region first. (This is basically the same as a while
// loop; see further comments in VisitWhileStmt.)
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = PGO.getCurrentRegionCount();
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
// The increment is essentially part of the body but it needs to include
@ -473,13 +475,13 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
RecordStmtCount(S);
Visit(S->getElement());
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Counter tracks the body of the loop.
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = PGO.getCurrentRegionCount();
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
setCount(BC.BreakCount + ParentCount + BackedgeCount + BC.ContinueCount -
@ -490,7 +492,7 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
void VisitSwitchStmt(const SwitchStmt *S) {
RecordStmtCount(S);
Visit(S->getCond());
PGO.setCurrentRegionUnreachable();
CurrentCount = 0;
BreakContinueStack.push_back(BreakContinue());
Visit(S->getBody());
// If the switch is inside a loop, add the continue counts.
@ -508,7 +510,7 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
// switch header and does not include fallthrough from the case before
// this one.
uint64_t CaseCount = PGO.getRegionCount(S);
setCount(PGO.getCurrentRegionCount() + CaseCount);
setCount(CurrentCount + CaseCount);
// We need the count without fallthrough in the mapping, so it's more useful
// for branch probabilities.
CountMap[S] = CaseCount;
@ -518,7 +520,7 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
void VisitIfStmt(const IfStmt *S) {
RecordStmtCount(S);
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
Visit(S->getCond());
// Counter tracks the "then" part of an if statement. The count for
@ -526,14 +528,14 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
uint64_t ThenCount = setCount(PGO.getRegionCount(S));
CountMap[S->getThen()] = ThenCount;
Visit(S->getThen());
uint64_t OutCount = PGO.getCurrentRegionCount();
uint64_t OutCount = CurrentCount;
uint64_t ElseCount = ParentCount - ThenCount;
if (S->getElse()) {
setCount(ElseCount);
CountMap[S->getElse()] = ElseCount;
Visit(S->getElse());
OutCount += PGO.getCurrentRegionCount();
OutCount += CurrentCount;
} else
OutCount += ElseCount;
setCount(OutCount);
@ -560,7 +562,7 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
void VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
RecordStmtCount(E);
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
Visit(E->getCond());
// Counter tracks the "true" part of a conditional operator. The
@ -568,12 +570,12 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
uint64_t TrueCount = setCount(PGO.getRegionCount(E));
CountMap[E->getTrueExpr()] = TrueCount;
Visit(E->getTrueExpr());
uint64_t OutCount = PGO.getCurrentRegionCount();
uint64_t OutCount = CurrentCount;
uint64_t FalseCount = setCount(ParentCount - TrueCount);
CountMap[E->getFalseExpr()] = FalseCount;
Visit(E->getFalseExpr());
OutCount += PGO.getCurrentRegionCount();
OutCount += CurrentCount;
setCount(OutCount);
RecordNextStmtCount = true;
@ -581,25 +583,25 @@ struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
void VisitBinLAnd(const BinaryOperator *E) {
RecordStmtCount(E);
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
Visit(E->getLHS());
// Counter tracks the right hand side of a logical and operator.
uint64_t RHSCount = setCount(PGO.getRegionCount(E));
CountMap[E->getRHS()] = RHSCount;
Visit(E->getRHS());
setCount(ParentCount + RHSCount - PGO.getCurrentRegionCount());
setCount(ParentCount + RHSCount - CurrentCount);
RecordNextStmtCount = true;
}
void VisitBinLOr(const BinaryOperator *E) {
RecordStmtCount(E);
uint64_t ParentCount = PGO.getCurrentRegionCount();
uint64_t ParentCount = CurrentCount;
Visit(E->getLHS());
// Counter tracks the right hand side of a logical or operator.
uint64_t RHSCount = setCount(PGO.getRegionCount(E));
CountMap[E->getRHS()] = RHSCount;
Visit(E->getRHS());
setCount(ParentCount + RHSCount - PGO.getCurrentRegionCount());
setCount(ParentCount + RHSCount - CurrentCount);
RecordNextStmtCount = true;
}
};

5
clang/lib/CodeGen/CodeGenPGO.h
View File

@ -60,11 +60,6 @@ public:
/// exits.
void setCurrentRegionCount(uint64_t Count) { CurrentRegionCount = Count; }
/// Indicate that the current region is never reached, and thus should have a
/// counter value of zero. This is important so that subsequent regions can
/// correctly track their parent counts.
void setCurrentRegionUnreachable() { setCurrentRegionCount(0); }
/// Check if an execution count is known for a given statement. If so, return
/// true and put the value in Count; else return false.
Optional<uint64_t> getStmtCount(const Stmt *S) {