Author: Tomasz Kamiński Date: 2023-07-18T08:31:38+02:00 New Revision: 61760bb98c4694651261b2e10df3fa6f669098ed
URL: https://github.com/llvm/llvm-project/commit/61760bb98c4694651261b2e10df3fa6f669098ed DIFF: https://github.com/llvm/llvm-project/commit/61760bb98c4694651261b2e10df3fa6f669098ed.diff LOG: [analyzer] Bind return value for assigment and copies of trivial empty classes We now properly bind return value of the trivial copy constructor and assignments of the empty objects. Such operations do not perform any loads from the source, however they preserve identity of the assigned object: ``` Empty e; auto& x = (e = Empty()); clang_analyzer_dump(x); // &e, was Unknown ``` Reviewed By: xazax.hun Differential Revision: https://reviews.llvm.org/D155442 Added: clang/test/Analysis/ctor-trivial-copy.cpp Modified: clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp Removed: ################################################################################ diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp index d1894d4447a2e9..7ee7c1394a670a 100644 --- a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp +++ b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp @@ -61,30 +61,30 @@ void ExprEngine::performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred, AlwaysReturnsLValue = true; } - assert(ThisRD); - if (ThisRD->isEmpty()) { - // Do nothing for empty classes. Otherwise it'd retrieve an UnknownVal - // and bind it and RegionStore would think that the actual value - // in this region at this offset is unknown. - return; - } - const LocationContext *LCtx = Pred->getLocationContext(); + const Expr *CallExpr = Call.getOriginExpr(); ExplodedNodeSet Dst; Bldr.takeNodes(Pred); - SVal V = Call.getArgSVal(0); - - // If the value being copied is not unknown, load from its location to get - // an aggregate rvalue. - if (std::optional<Loc> L = V.getAs<Loc>()) - V = Pred->getState()->getSVal(*L); - else - assert(V.isUnknownOrUndef()); + assert(ThisRD); + if (!ThisRD->isEmpty()) { + // Load the source value only for non-empty classes. + // Otherwise it'd retrieve an UnknownVal + // and bind it and RegionStore would think that the actual value + // in this region at this offset is unknown. + SVal V = Call.getArgSVal(0); - const Expr *CallExpr = Call.getOriginExpr(); - evalBind(Dst, CallExpr, Pred, ThisVal, V, true); + // If the value being copied is not unknown, load from its location to get + // an aggregate rvalue. + if (std::optional<Loc> L = V.getAs<Loc>()) + V = Pred->getState()->getSVal(*L); + else + assert(V.isUnknownOrUndef()); + evalBind(Dst, CallExpr, Pred, ThisVal, V, true); + } else { + Dst.Add(Pred); + } PostStmt PS(CallExpr, LCtx); for (ExplodedNode *N : Dst) { diff --git a/clang/test/Analysis/ctor-trivial-copy.cpp b/clang/test/Analysis/ctor-trivial-copy.cpp new file mode 100644 index 00000000000000..5ed188aa8f1eae --- /dev/null +++ b/clang/test/Analysis/ctor-trivial-copy.cpp @@ -0,0 +1,34 @@ +// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -analyzer-config c++-inlining=constructors -verify %s + + +template<typename T> +void clang_analyzer_dump(T&); + +struct aggr { + int x; + int y; +}; + +struct empty { +}; + +void test_copy_return() { + aggr s1 = {1, 2}; + aggr const& cr1 = aggr(s1); + clang_analyzer_dump(cr1); // expected-warning-re {{&lifetime_extended_object{aggr, cr1, S{{[0-9]+}}} }} + + empty s2; + empty const& cr2 = empty{s2}; + clang_analyzer_dump(cr2); // expected-warning-re {{&lifetime_extended_object{empty, cr2, S{{[0-9]+}}} }} +} + +void test_assign_return() { + aggr s1 = {1, 2}; + aggr d1; + clang_analyzer_dump(d1 = s1); // expected-warning {{&d1 }} + + empty s2; + empty d2; + clang_analyzer_dump(d2 = s2); // expected-warning {{&d2 }} was Unknown +} + _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
