NoQ updated this revision to Diff 148681.
NoQ added a comment.
Optimize `simplifySVal()` instead of reducing the threshold.
I'll address the memoization separately.
https://reviews.llvm.org/D47155
Files:
include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
test/Analysis/hangs.c
Index: test/Analysis/hangs.c
===================================================================
--- /dev/null
+++ test/Analysis/hangs.c
@@ -0,0 +1,30 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker core -verify %s
+
+// expected-no-diagnostics
+
+// Stuff that used to hang.
+
+int g();
+
+int f(int y) {
+ return y + g();
+}
+
+int produce_a_very_large_symbol(int x) {
+ return f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(
+ f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(x))))))))))))))))))))))))))))))));
+}
+
+void produce_an_exponentially_exploding_symbol(int x, int y) {
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+}
Index: lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
===================================================================
--- lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -1222,6 +1222,10 @@
ProgramStateRef State;
SValBuilder &SVB;
+ static bool isUnchanged(SymbolRef Sym, SVal Val) {
+ return Sym == Val.getAsSymbol();
+ }
+
public:
Simplifier(ProgramStateRef State)
: State(State), SVB(State->getStateManager().getSValBuilder()) {}
@@ -1231,15 +1235,16 @@
SVB.getKnownValue(State, nonloc::SymbolVal(S)))
return Loc::isLocType(S->getType()) ? (SVal)SVB.makeIntLocVal(*I)
: (SVal)SVB.makeIntVal(*I);
- return Loc::isLocType(S->getType()) ? (SVal)SVB.makeLoc(S)
- : nonloc::SymbolVal(S);
+ return SVB.makeSymbolVal(S);
}
// TODO: Support SymbolCast. Support IntSymExpr when/if we actually
// start producing them.
SVal VisitSymIntExpr(const SymIntExpr *S) {
SVal LHS = Visit(S->getLHS());
+ if (isUnchanged(S->getLHS(), LHS))
+ return SVB.makeSymbolVal(S);
SVal RHS;
// By looking at the APSInt in the right-hand side of S, we cannot
// figure out if it should be treated as a Loc or as a NonLoc.
@@ -1264,6 +1269,8 @@
SVal VisitSymSymExpr(const SymSymExpr *S) {
SVal LHS = Visit(S->getLHS());
SVal RHS = Visit(S->getRHS());
+ if (isUnchanged(S->getLHS(), LHS) && isUnchanged(S->getRHS(), RHS))
+ return SVB.makeSymbolVal(S);
return SVB.evalBinOp(State, S->getOpcode(), LHS, RHS, S->getType());
}
Index: include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
@@ -367,6 +367,15 @@
return loc::ConcreteInt(BasicVals.getValue(integer));
}
+ /// Make an SVal that represents the given symbol. This follows the
convention
+ /// of representing Loc-type symbols (symbolic pointers and references)
+ /// as Loc values wrapping the symbol rather than as plain symbol values.
+ SVal makeSymbolVal(SymbolRef Sym) {
+ if (Loc::isLocType(Sym->getType()))
+ return makeLoc(Sym);
+ return nonloc::SymbolVal(Sym);
+ }
+
/// Return a memory region for the 'this' object reference.
loc::MemRegionVal getCXXThis(const CXXMethodDecl *D,
const StackFrameContext *SFC);
Index: test/Analysis/hangs.c
===================================================================
--- /dev/null
+++ test/Analysis/hangs.c
@@ -0,0 +1,30 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker core -verify %s
+
+// expected-no-diagnostics
+
+// Stuff that used to hang.
+
+int g();
+
+int f(int y) {
+ return y + g();
+}
+
+int produce_a_very_large_symbol(int x) {
+ return f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(
+ f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(x))))))))))))))))))))))))))))))));
+}
+
+void produce_an_exponentially_exploding_symbol(int x, int y) {
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+ x += y; y += x + g();
+}
Index: lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
===================================================================
--- lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -1222,6 +1222,10 @@
ProgramStateRef State;
SValBuilder &SVB;
+ static bool isUnchanged(SymbolRef Sym, SVal Val) {
+ return Sym == Val.getAsSymbol();
+ }
+
public:
Simplifier(ProgramStateRef State)
: State(State), SVB(State->getStateManager().getSValBuilder()) {}
@@ -1231,15 +1235,16 @@
SVB.getKnownValue(State, nonloc::SymbolVal(S)))
return Loc::isLocType(S->getType()) ? (SVal)SVB.makeIntLocVal(*I)
: (SVal)SVB.makeIntVal(*I);
- return Loc::isLocType(S->getType()) ? (SVal)SVB.makeLoc(S)
- : nonloc::SymbolVal(S);
+ return SVB.makeSymbolVal(S);
}
// TODO: Support SymbolCast. Support IntSymExpr when/if we actually
// start producing them.
SVal VisitSymIntExpr(const SymIntExpr *S) {
SVal LHS = Visit(S->getLHS());
+ if (isUnchanged(S->getLHS(), LHS))
+ return SVB.makeSymbolVal(S);
SVal RHS;
// By looking at the APSInt in the right-hand side of S, we cannot
// figure out if it should be treated as a Loc or as a NonLoc.
@@ -1264,6 +1269,8 @@
SVal VisitSymSymExpr(const SymSymExpr *S) {
SVal LHS = Visit(S->getLHS());
SVal RHS = Visit(S->getRHS());
+ if (isUnchanged(S->getLHS(), LHS) && isUnchanged(S->getRHS(), RHS))
+ return SVB.makeSymbolVal(S);
return SVB.evalBinOp(State, S->getOpcode(), LHS, RHS, S->getType());
}
Index: include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
@@ -367,6 +367,15 @@
return loc::ConcreteInt(BasicVals.getValue(integer));
}
+ /// Make an SVal that represents the given symbol. This follows the convention
+ /// of representing Loc-type symbols (symbolic pointers and references)
+ /// as Loc values wrapping the symbol rather than as plain symbol values.
+ SVal makeSymbolVal(SymbolRef Sym) {
+ if (Loc::isLocType(Sym->getType()))
+ return makeLoc(Sym);
+ return nonloc::SymbolVal(Sym);
+ }
+
/// Return a memory region for the 'this' object reference.
loc::MemRegionVal getCXXThis(const CXXMethodDecl *D,
const StackFrameContext *SFC);
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