ymandel created this revision.
ymandel added reviewers: sgatev, gribozavr2.
ymandel requested review of this revision.
Herald added a project: clang.
Currently, the transfer function returns a new lattice element, which forces an
unnecessary copy on processing each CFG statement.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D116834
Files:
clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
clang/include/clang/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.h
clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
clang/unittests/Analysis/FlowSensitive/MultiVarConstantPropagationTest.cpp
clang/unittests/Analysis/FlowSensitive/NoopAnalysis.h
clang/unittests/Analysis/FlowSensitive/SingleVarConstantPropagationTest.cpp
clang/unittests/Analysis/FlowSensitive/TypeErasedDataflowAnalysisTest.cpp
Index: clang/unittests/Analysis/FlowSensitive/TypeErasedDataflowAnalysisTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/TypeErasedDataflowAnalysisTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/TypeErasedDataflowAnalysisTest.cpp
@@ -113,9 +113,8 @@
static NonConvergingLattice initialElement() { return {0}; }
- NonConvergingLattice transfer(const Stmt *S, const NonConvergingLattice &E,
- Environment &Env) {
- return {E.State + 1};
+ void transfer(const Stmt *S, NonConvergingLattice &E, Environment &Env) {
+ ++E.State;
}
};
@@ -165,15 +164,12 @@
static FunctionCallLattice initialElement() { return {}; }
- FunctionCallLattice transfer(const Stmt *S, const FunctionCallLattice &E,
- Environment &Env) {
- FunctionCallLattice R = E;
+ void transfer(const Stmt *S, FunctionCallLattice &R, Environment &Env) {
if (auto *C = dyn_cast<CallExpr>(S)) {
if (auto *F = dyn_cast<FunctionDecl>(C->getCalleeDecl())) {
R.CalledFunctions.insert(F->getNameInfo().getAsString());
}
}
- return R;
}
};
Index: clang/unittests/Analysis/FlowSensitive/SingleVarConstantPropagationTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/SingleVarConstantPropagationTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/SingleVarConstantPropagationTest.cpp
@@ -121,9 +121,8 @@
return ConstantPropagationLattice::bottom();
}
- ConstantPropagationLattice transfer(const Stmt *S,
- const ConstantPropagationLattice &Element,
- Environment &Env) {
+ void transfer(const Stmt *S, ConstantPropagationLattice &Element,
+ Environment &Env) {
auto matcher = stmt(
anyOf(declStmt(hasSingleDecl(varDecl(hasType(isInteger()),
hasInitializer(expr().bind(kInit)))
@@ -137,7 +136,7 @@
ASTContext &Context = getASTContext();
auto Results = match(matcher, *S, Context);
if (Results.empty())
- return Element;
+ return;
const BoundNodes &Nodes = Results[0];
const auto *Var = Nodes.getNodeAs<clang::VarDecl>(kVar);
@@ -145,30 +144,26 @@
if (const auto *E = Nodes.getNodeAs<clang::Expr>(kInit)) {
Expr::EvalResult R;
- if (E->EvaluateAsInt(R, Context) && R.Val.isInt())
- return ConstantPropagationLattice{
- {{Var, R.Val.getInt().getExtValue()}}};
- return ConstantPropagationLattice::top();
- }
-
- if (Nodes.getNodeAs<clang::Expr>(kJustAssignment)) {
+ Element =
+ (E->EvaluateAsInt(R, Context) && R.Val.isInt())
+ ? ConstantPropagationLattice{{{Var,
+ R.Val.getInt().getExtValue()}}}
+ : ConstantPropagationLattice::top();
+ } else if (Nodes.getNodeAs<clang::Expr>(kJustAssignment)) {
const auto *RHS = Nodes.getNodeAs<clang::Expr>(kRHS);
assert(RHS != nullptr);
Expr::EvalResult R;
- if (RHS->EvaluateAsInt(R, Context) && R.Val.isInt())
- return ConstantPropagationLattice{
- {{Var, R.Val.getInt().getExtValue()}}};
- return ConstantPropagationLattice::top();
- }
-
- // Any assignment involving the expression itself resets the variable to
- // "unknown". A more advanced analysis could try to evaluate the compound
- // assignment. For example, `x += 0` need not invalidate `x`.
- if (Nodes.getNodeAs<clang::Expr>(kAssignment))
- return ConstantPropagationLattice::top();
-
- llvm_unreachable("expected at least one bound identifier");
+ Element =
+ (RHS->EvaluateAsInt(R, Context) && R.Val.isInt())
+ ? ConstantPropagationLattice{{{Var,
+ R.Val.getInt().getExtValue()}}}
+ : ConstantPropagationLattice::top();
+ } else if (Nodes.getNodeAs<clang::Expr>(kAssignment))
+ // Any assignment involving the expression itself resets the variable to
+ // "unknown". A more advanced analysis could try to evaluate the compound
+ // assignment. For example, `x += 0` need not invalidate `x`.
+ Element = ConstantPropagationLattice::top();
}
};
Index: clang/unittests/Analysis/FlowSensitive/NoopAnalysis.h
===================================================================
--- clang/unittests/Analysis/FlowSensitive/NoopAnalysis.h
+++ clang/unittests/Analysis/FlowSensitive/NoopAnalysis.h
@@ -44,9 +44,7 @@
static NoopLattice initialElement() { return {}; }
- NoopLattice transfer(const Stmt *S, const NoopLattice &E, Environment &Env) {
- return {};
- }
+ void transfer(const Stmt *S, NoopLattice &E, Environment &Env) {}
};
} // namespace dataflow
Index: clang/unittests/Analysis/FlowSensitive/MultiVarConstantPropagationTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/MultiVarConstantPropagationTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/MultiVarConstantPropagationTest.cpp
@@ -132,8 +132,8 @@
return ConstantPropagationLattice::bottom();
}
- ConstantPropagationLattice
- transfer(const Stmt *S, ConstantPropagationLattice Vars, Environment &Env) {
+ void transfer(const Stmt *S, ConstantPropagationLattice &Vars,
+ Environment &Env) {
auto matcher =
stmt(anyOf(declStmt(hasSingleDecl(
varDecl(decl().bind(kVar), hasType(isInteger()),
@@ -148,7 +148,7 @@
ASTContext &Context = getASTContext();
auto Results = match(matcher, *S, Context);
if (Results.empty())
- return Vars;
+ return;
const BoundNodes &Nodes = Results[0];
const auto *Var = Nodes.getNodeAs<clang::VarDecl>(kVar);
@@ -165,10 +165,7 @@
// is (it is implementation defined), so we set it to top.
Vars[Var] = ValueLattice::top();
}
- return Vars;
- }
-
- if (Nodes.getNodeAs<clang::Expr>(kJustAssignment)) {
+ } else if (Nodes.getNodeAs<clang::Expr>(kJustAssignment)) {
const auto *E = Nodes.getNodeAs<clang::Expr>(kRHS);
assert(E != nullptr);
@@ -176,18 +173,12 @@
Vars[Var] = (E->EvaluateAsInt(R, Context) && R.Val.isInt())
? ValueLattice(R.Val.getInt().getExtValue())
: ValueLattice::top();
- return Vars;
- }
-
- // Any assignment involving the expression itself resets the variable to
- // "unknown". A more advanced analysis could try to evaluate the compound
- // assignment. For example, `x += 0` need not invalidate `x`.
- if (Nodes.getNodeAs<clang::Expr>(kAssignment)) {
+ } else if (Nodes.getNodeAs<clang::Expr>(kAssignment)) {
+ // Any assignment involving the expression itself resets the variable to
+ // "unknown". A more advanced analysis could try to evaluate the compound
+ // assignment. For example, `x += 0` need not invalidate `x`.
Vars[Var] = ValueLattice::top();
- return Vars;
}
-
- llvm_unreachable("expected at least one bound identifier");
}
};
Index: clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
+++ clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
@@ -123,7 +123,7 @@
assert(S != nullptr);
transfer(*S, State.Env);
- State.Lattice = Analysis.transferTypeErased(S, State.Lattice, State.Env);
+ Analysis.transferTypeErased(S, State.Lattice, State.Env);
if (HandleTransferredStmt != nullptr)
HandleTransferredStmt(CfgStmt.getValue(), State);
Index: clang/include/clang/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.h
===================================================================
--- clang/include/clang/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.h
+++ clang/include/clang/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.h
@@ -64,9 +64,8 @@
/// Applies the analysis transfer function for a given statement and
/// type-erased lattice element.
- virtual TypeErasedLattice transferTypeErased(const Stmt *,
- const TypeErasedLattice &,
- Environment &) = 0;
+ virtual void transferTypeErased(const Stmt *, TypeErasedLattice &,
+ Environment &) = 0;
};
/// Type-erased model of the program at a given program point.
Index: clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
===================================================================
--- clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
+++ clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
@@ -39,9 +39,8 @@
/// must provide the following public members:
/// * `LatticeT initialElement()` - returns a lattice element that models the
/// initial state of a basic block;
-/// * `LatticeT transfer(const Stmt *, const LatticeT &, Environment &)` -
-/// applies the analysis transfer function for a given statement and lattice
-/// element.
+/// * `void transfer(const Stmt *, LatticeT &, Environment &)` - applies the
+/// analysis transfer function for a given statement and lattice element.
///
/// `LatticeT` is a bounded join-semilattice that is used by `Derived` and must
/// provide the following public members:
@@ -79,11 +78,10 @@
return L1 == L2;
}
- TypeErasedLattice transferTypeErased(const Stmt *Stmt,
- const TypeErasedLattice &E,
- Environment &Env) final {
- const Lattice &L = llvm::any_cast<const Lattice &>(E.Value);
- return {static_cast<Derived *>(this)->transfer(Stmt, L, Env)};
+ void transferTypeErased(const Stmt *Stmt, TypeErasedLattice &E,
+ Environment &Env) final {
+ Lattice &L = llvm::any_cast<Lattice &>(E.Value);
+ static_cast<Derived *>(this)->transfer(Stmt, L, Env);
}
private:
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