=?utf-8?q?Donát?= Nagy <donat.n...@ericsson.com>,NagyDonat
<donat.n...@ericsson.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/83...@github.com>
================
@@ -27,20 +27,48 @@ class IdentifierInfo;
namespace clang {
namespace ento {
-
-enum CallDescriptionFlags : unsigned {
- CDF_None = 0,
-
- /// Describes a C standard function that is sometimes implemented as a macro
- /// that expands to a compiler builtin with some __builtin prefix.
- /// The builtin may as well have a few extra arguments on top of the
requested
- /// number of arguments.
- CDF_MaybeBuiltin = 1 << 0,
-};
-
-/// This class represents a description of a function call using the number of
-/// arguments and the name of the function.
+/// A `CallDescription` is a pattern that can be used to _match_ calls
+/// based on the qualified name and the argument/parameter counts.
class CallDescription {
+public:
+ enum class Mode {
+ /// Match calls to functions from the C standard library. On some platforms
+ /// some functions may be implemented as macros that expand to calls to
+ /// built-in variants of the given functions, so in this mode we use some
+ /// heuristics to recognize these implementation-defined variants:
+ /// - We also accept calls where the name is derived from the specified
+ /// name by adding "__builtin" or similar prefixes/suffixes.
+ /// - We also accept calls where the number of arguments or parameters is
+ /// greater than the specified value.
+ /// For the exact heuristics, see CheckerContext::isCLibraryFunction().
+ /// Note that functions whose declaration context is not a TU (e.g.
+ /// methods, functions in namespaces) are not accepted as C library
+ /// functions.
+ /// FIXME: If I understand it correctly, this discards calls where C++ code
+ /// refers a C library function through the namespace `std::` via headers
+ /// like <cstdlib>.
+ CLibrary,
----------------
NagyDonat wrote:
> I saw cases at MallocChecker where it is not used, then it should be used in
> these cases too.
In fact that was the original reason why I started to work on
`CallDescription`s: there was an open source bug report
(https://github.com/llvm/llvm-project/issues/81597) where MallocChecker
recognized a C++ method named `free` as if it was the well-known function
`free`.
Now I realize that it would've been possible to resolve that bug by just adding
`CDF_MaybeBuiltin` to the `CallDescription` for `free`, but I was misled by the
name `CDF_MaybeBuiltin` and thought that I need to introduce a new matching
mode that says "_must_ be function".
After merging this commit, I'll quickly do a followup commit that fixes
`MallocChecker`, but then I'll continue with cleaning up the other checkers as
well.
https://github.com/llvm/llvm-project/pull/83432
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