maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[analyzer] Fix inefficiency in dead symbol removal 

Summary:
ScanReachableSymbols uses a "visited" set to avoid scanning the same object
twice. However, it did not use the optimization for LazyCompoundVal objects,
which resulted in exponential complexity for long chains of temporary objects.
Adding this resulted in a decrease of analysis time from >3h to 3 seconds for
some files.

Reviewers: jordan_rose

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1398

llvm-svn: 188677
This commit is contained in:
Pavel Labath 2013-08-19 15:23:34 +00:00
parent 4a9df8a768
commit 71bb987997
2 changed files with 21 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
clang/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
View File

@ -798,7 +798,7 @@ CB ProgramState::scanReachableSymbols(const MemRegion * const *beg,
/// A Utility class that allows to visit the reachable symbols using a custom
/// SymbolVisitor.
class ScanReachableSymbols {
typedef llvm::DenseMap<const void*, unsigned> VisitedItems;
typedef llvm::DenseSet<const void*> VisitedItems;
VisitedItems visited;
ProgramStateRef state;
@ -808,6 +808,7 @@ public:
ScanReachableSymbols(ProgramStateRef st, SymbolVisitor& v)
: state(st), visitor(v) {}
bool scan(nonloc::LazyCompoundVal val);
bool scan(nonloc::CompoundVal val);
bool scan(SVal val);
bool scan(const MemRegion *R);

36
clang/lib/StaticAnalyzer/Core/ProgramState.cpp
View File

@ -526,6 +526,19 @@ ProgramStateRef ProgramStateManager::removeGDM(ProgramStateRef state, void *Key)
return getPersistentState(NewState);
}
bool ScanReachableSymbols::scan(nonloc::LazyCompoundVal val) {
bool wasVisited = !visited.insert(val.getCVData()).second;
if (wasVisited)
return true;
StoreManager &StoreMgr = state->getStateManager().getStoreManager();
// FIXME: We don't really want to use getBaseRegion() here because pointer
// arithmetic doesn't apply, but scanReachableSymbols only accepts base
// regions right now.
const MemRegion *R = val.getRegion()->getBaseRegion();
return StoreMgr.scanReachableSymbols(val.getStore(), R, *this);
}
bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I)
if (!scan(*I))
@ -535,10 +548,9 @@ bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
}
bool ScanReachableSymbols::scan(const SymExpr *sym) {
unsigned &isVisited = visited[sym];
if (isVisited)
bool wasVisited = !visited.insert(sym).second;
if (wasVisited)
return true;
isVisited = 1;
if (!visitor.VisitSymbol(sym))
return false;
@ -570,16 +582,8 @@ bool ScanReachableSymbols::scan(SVal val) {
return scan(X->getRegion());
if (Optional<nonloc::LazyCompoundVal> X =
val.getAs<nonloc::LazyCompoundVal>()) {
StoreManager &StoreMgr = state->getStateManager().getStoreManager();
// FIXME: We don't really want to use getBaseRegion() here because pointer
// arithmetic doesn't apply, but scanReachableSymbols only accepts base
// regions right now.
if (!StoreMgr.scanReachableSymbols(X->getStore(),
X->getRegion()->getBaseRegion(),
*this))
return false;
}
val.getAs<nonloc::LazyCompoundVal>())
return scan(*X);
if (Optional<nonloc::LocAsInteger> X = val.getAs<nonloc::LocAsInteger>())
return scan(X->getLoc());
@ -600,11 +604,9 @@ bool ScanReachableSymbols::scan(const MemRegion *R) {
if (isa<MemSpaceRegion>(R))
return true;
unsigned &isVisited = visited[R];
if (isVisited)
bool wasVisited = !visited.insert(R).second;
if (wasVisited)
return true;
isVisited = 1;
if (!visitor.VisitMemRegion(R))
return false;