Author: Balázs Kéri Date: 2025-11-17T11:59:09+01:00 New Revision: dfac905925a66f7077d9ade3f2719f4fc9164aa3
URL: https://github.com/llvm/llvm-project/commit/dfac905925a66f7077d9ade3f2719f4fc9164aa3 DIFF: https://github.com/llvm/llvm-project/commit/dfac905925a66f7077d9ade3f2719f4fc9164aa3.diff LOG: [clang][analyzer] Extend lifetime of dynamic extent information (#163562) Symbols used for dynamic extent information of memory regions are now kept as live as long as the memory region exists. Added: Modified: clang/include/clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h clang/lib/StaticAnalyzer/Core/DynamicExtent.cpp clang/lib/StaticAnalyzer/Core/ExprEngine.cpp clang/test/Analysis/ArrayBound/verbose-tests.c Removed: ################################################################################ diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h index 1a9bef06b15a4..440603fb4d8c7 100644 --- a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h +++ b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h @@ -58,6 +58,8 @@ SVal getDynamicExtentWithOffset(ProgramStateRef State, SVal BufV); DefinedOrUnknownSVal getDynamicElementCountWithOffset(ProgramStateRef State, SVal BufV, QualType Ty); +void markAllDynamicExtentLive(ProgramStateRef State, SymbolReaper &SymReaper); + } // namespace ento } // namespace clang diff --git a/clang/lib/StaticAnalyzer/Core/DynamicExtent.cpp b/clang/lib/StaticAnalyzer/Core/DynamicExtent.cpp index 34078dbce0b68..e5d5e0113eb2c 100644 --- a/clang/lib/StaticAnalyzer/Core/DynamicExtent.cpp +++ b/clang/lib/StaticAnalyzer/Core/DynamicExtent.cpp @@ -128,5 +128,12 @@ ProgramStateRef setDynamicExtent(ProgramStateRef State, const MemRegion *MR, return State->set<DynamicExtentMap>(MR->StripCasts(), Size); } +void markAllDynamicExtentLive(ProgramStateRef State, SymbolReaper &SymReaper) { + for (const auto &I : State->get<DynamicExtentMap>()) + if (SymbolRef Sym = I.second.getAsSymbol()) + if (SymReaper.isLiveRegion(I.first)) + SymReaper.markLive(Sym); +} + } // namespace ento } // namespace clang diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp index 4e472b7fc38b0..a759aee47b8ea 100644 --- a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp +++ b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp @@ -1079,6 +1079,11 @@ void ExprEngine::removeDead(ExplodedNode *Pred, ExplodedNodeSet &Out, getCheckerManager().runCheckersForDeadSymbols(CheckedSet, Pred, SymReaper, DiagnosticStmt, *this, K); + // Extend lifetime of symbols used for dynamic extent while the parent region + // is live. In this way size information about memory allocations is not lost + // if the region remains live. + markAllDynamicExtentLive(CleanedState, SymReaper); + // For each node in CheckedSet, generate CleanedNodes that have the // environment, the store, and the constraints cleaned up but have the // user-supplied states as the predecessors. diff --git a/clang/test/Analysis/ArrayBound/verbose-tests.c b/clang/test/Analysis/ArrayBound/verbose-tests.c index e3416886d13e5..c0da93ea48591 100644 --- a/clang/test/Analysis/ArrayBound/verbose-tests.c +++ b/clang/test/Analysis/ArrayBound/verbose-tests.c @@ -381,30 +381,12 @@ int *symbolicExtent(int arg) { return 0; int *mem = (int*)malloc(arg); - // TODO: without the following reference to 'arg', the analyzer would discard - // the range information about (the symbolic value of) 'arg'. This is - // incorrect because while the variable itself is inaccessible, it becomes - // the symbolic extent of 'mem', so we still want to reason about its - // potential values. - (void)arg; - mem[8] = -2; // expected-warning@-1 {{Out of bound access to memory after the end of the heap area}} // expected-note@-2 {{Access of 'int' element in the heap area at index 8}} return mem; } -int *symbolicExtentDiscardedRangeInfo(int arg) { - // This is a copy of the case 'symbolicExtent' without the '(void)arg' hack. - // TODO: if the analyzer can detect the out-of-bounds access within this - // testcase, then remove this and the `(void)arg` hack from `symbolicExtent`. - if (arg >= 5) - return 0; - int *mem = (int*)malloc(arg); - mem[8] = -2; - return mem; -} - void symbolicIndex(int arg) { // expected-note@+2 {{Assuming 'arg' is >= 12}} // expected-note@+1 {{Taking true branch}} @@ -426,9 +408,5 @@ int *nothingIsCertain(int x, int y) { // {{Access of 'int' element in the heap area at an overflowing index}} // but apparently the analyzer isn't smart enough to deduce this. - // Keep constraints alive. (Without this, the overeager garbage collection of - // constraints would _also_ prevent the intended behavior in this testcase.) - (void)x; - return mem; } _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
