[clang][analyzer] Fix incorrect range of 'ftell' in the StdLibraryFunctionsChecker #77576
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…ctionsChecker According to https://pubs.opengroup.org/onlinepubs/9699919799/, the return value of 'ftell' is not restricted to > 0, and may return 0 in real world.
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@llvm/pr-subscribers-clang-static-analyzer-1 @llvm/pr-subscribers-clang Author: Ben Shi (benshi001) ChangesAccording to https://pubs.opengroup.org/onlinepubs/9699919799/, the return value of 'ftell' is not restricted to > 0, and may return 0 in real world. And the corresponding unit test also show https://github.com/llvm/llvm-project/blob/main/clang/test/Analysis/stream-errno.c#L194 Full diff: https://github.com/llvm/llvm-project/pull/77576.diff 1 Files Affected:
diff --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
index 32a2deab871c79..3b36565681a7f3 100644
--- a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
@@ -2274,7 +2274,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
addToFunctionSummaryMap(
"ftell", Signature(ArgTypes{FilePtrTy}, RetType{LongTy}),
Summary(NoEvalCall)
- .Case({ReturnValueCondition(WithinRange, Range(1, LongMax))},
+ .Case({ReturnValueCondition(WithinRange, Range(0, LongMax))},
ErrnoUnchanged, GenericSuccessMsg)
.Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant, GenericFailureMsg)
.ArgConstraint(NotNull(ArgNo(0))));
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balazske
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Jan 10, 2024
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Jan 28, 2024
…ctionsChecker (llvm#77576) According to https://pubs.opengroup.org/onlinepubs/9699919799/, the return value of `ftell` is not restricted to `> 0`, and may return `0` in real world.
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According to https://pubs.opengroup.org/onlinepubs/9699919799/, the return value of
ftellis not restricted to> 0, and may return0in real world.And the corresponding unit test also show
Ret >= 0notRet > 0.https://github.com/llvm/llvm-project/blob/main/clang/test/Analysis/stream-errno.c#L194