vabridgers created this revision. vabridgers added reviewers: martong, NoQ. Herald added subscribers: ASDenysPetrov, Charusso, donat.nagy, Szelethus, mikhail.ramalho, a.sidorin, rnkovacs, szepet, xazax.hun. Herald added a project: clang.
This check was causing a crash in a test case where the 0th argument was uninitialized ('Assertion `T::isKind(*this)' at line SVals.h:104). This was happening since the argument was actually undefined, but the castAs assumes the value is DefinedOrUnknownSVal. The fix appears to be simply to check for an undefined value and skip the check allowing the uninitalized value checker to detect the error. I included a test case that I verified to produce the negative case prior to the fix, and passes with the fix. Repository: rG LLVM Github Monorepo https://reviews.llvm.org/D77012 Files: clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp clang/test/Analysis/std-c-library-functions.c Index: clang/test/Analysis/std-c-library-functions.c =================================================================== --- clang/test/Analysis/std-c-library-functions.c +++ clang/test/Analysis/std-c-library-functions.c @@ -89,6 +89,16 @@ clang_analyzer_eval(z <= y); // expected-warning{{TRUE}} } + +void test_fread_uninitialized(void) +{ + void *ptr; + size_t sz; + size_t nmem; + FILE *fp; + (void) fread(ptr, sz, nmem, fp); // expected-warning {{1st function call argument is an uninitialized value}} +} + ssize_t getline(char **, size_t *, FILE *); void test_getline(FILE *fp) { char *line = 0; Index: clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp =================================================================== --- clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp +++ clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp @@ -190,6 +190,9 @@ ProgramStateRef apply(ProgramStateRef State, const CallEvent &Call, const Summary &Summary) const override { SVal V = getArgSVal(Call, getArgNo()); + if (V.isUndef()) + return State; + DefinedOrUnknownSVal L = V.castAs<DefinedOrUnknownSVal>(); if (!L.getAs<Loc>()) return State;
Index: clang/test/Analysis/std-c-library-functions.c =================================================================== --- clang/test/Analysis/std-c-library-functions.c +++ clang/test/Analysis/std-c-library-functions.c @@ -89,6 +89,16 @@ clang_analyzer_eval(z <= y); // expected-warning{{TRUE}} } + +void test_fread_uninitialized(void) +{ + void *ptr; + size_t sz; + size_t nmem; + FILE *fp; + (void) fread(ptr, sz, nmem, fp); // expected-warning {{1st function call argument is an uninitialized value}} +} + ssize_t getline(char **, size_t *, FILE *); void test_getline(FILE *fp) { char *line = 0; Index: clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp =================================================================== --- clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp +++ clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp @@ -190,6 +190,9 @@ ProgramStateRef apply(ProgramStateRef State, const CallEvent &Call, const Summary &Summary) const override { SVal V = getArgSVal(Call, getArgNo()); + if (V.isUndef()) + return State; + DefinedOrUnknownSVal L = V.castAs<DefinedOrUnknownSVal>(); if (!L.getAs<Loc>()) return State;
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