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merged 2 commits into from
Aug 19, 2024
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[clang][dataflow] Collect local variables referenced within a functio… #104459

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5aaa8c5
[clang][dataflow] Collect local variables referenced within a functio…
bazuzi Aug 15, 2024
0852bb9
Add test confirming local non-static, non-param variables are included.
bazuzi Aug 19, 2024
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3 changes: 3 additions & 0 deletions clang/include/clang/Analysis/FlowSensitive/ASTOps.h
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Original file line number Diff line number Diff line change
Expand Up @@ -139,6 +139,9 @@ struct ReferencedDecls {
/// All variables with static storage duration, notably including static
/// member variables and static variables declared within a function.
llvm::DenseSet<const VarDecl *> Globals;
/// Local variables, not including parameters or static variables declared
/// within a function.
llvm::DenseSet<const VarDecl *> Locals;
/// Free functions and member functions which are referenced (but not
/// necessarily called).
llvm::DenseSet<const FunctionDecl *> Functions;
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9 changes: 9 additions & 0 deletions clang/lib/Analysis/FlowSensitive/ASTOps.cpp
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Expand Up @@ -170,6 +170,13 @@ static void insertIfGlobal(const Decl &D,
Globals.insert(V);
}

static void insertIfLocal(const Decl &D,
llvm::DenseSet<const VarDecl *> &Locals) {
if (auto *V = dyn_cast<VarDecl>(&D))
if (V->hasLocalStorage() && !isa<ParmVarDecl>(V))
Locals.insert(V);
}

static void insertIfFunction(const Decl &D,
llvm::DenseSet<const FunctionDecl *> &Funcs) {
if (auto *FD = dyn_cast<FunctionDecl>(&D))
Expand Down Expand Up @@ -220,12 +227,14 @@ class ReferencedDeclsVisitor

bool VisitDecl(Decl *D) {
insertIfGlobal(*D, Referenced.Globals);
insertIfLocal(*D, Referenced.Locals);
insertIfFunction(*D, Referenced.Functions);
return true;
}

bool VisitDeclRefExpr(DeclRefExpr *E) {
insertIfGlobal(*E->getDecl(), Referenced.Globals);
insertIfLocal(*E->getDecl(), Referenced.Locals);
insertIfFunction(*E->getDecl(), Referenced.Functions);
return true;
}
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22 changes: 22 additions & 0 deletions clang/unittests/Analysis/FlowSensitive/ASTOpsTest.cpp
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Expand Up @@ -85,4 +85,26 @@ TEST(ASTOpsTest, ReferencedDeclsOnUnionInitList) {
UnorderedElementsAre(IDecl));
}

TEST(ASTOpsTest, ReferencedDeclsLocalsNotParamsOrStatics) {
std::string Code = R"cc(
void func(int Param) {
static int Static = 0;
int Local = Param;
Local = Static;
}
)cc";
std::unique_ptr<ASTUnit> Unit =
tooling::buildASTFromCodeWithArgs(Code, {"-fsyntax-only", "-std=c++17"});
auto &ASTCtx = Unit->getASTContext();

ASSERT_EQ(ASTCtx.getDiagnostics().getClient()->getNumErrors(), 0U);

auto *Func = cast<FunctionDecl>(findValueDecl(ASTCtx, "func"));
ASSERT_NE(Func, nullptr);
auto *LocalDecl = cast<VarDecl>(findValueDecl(ASTCtx, "Local"));

EXPECT_THAT(getReferencedDecls(*Func).Locals,
UnorderedElementsAre(LocalDecl));
}

} // namespace
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