https://github.com/NagyDonat created
https://github.com/llvm/llvm-project/pull/84469
Previously, the function `isCLibraryFunction()` and logic relying on it only
accepted functions that are declared directly within a TU (i.e. not in a
namespace or a class). However C++ headers like <cstdlib> declare many C
standard library functions within the namespace `std`, so this commit ensures
that functions within the namespace `std` are also accepted.
After this commit it will be possible to match functions like `malloc` or
`free` with `CallDescription::Mode::CLibrary`.
>From c357aa998204e6693430c801f5b7d3a9e5e09e37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Don=C3=A1t=20Nagy?= <donat.n...@ericsson.com>
Date: Fri, 8 Mar 2024 13:06:01 +0100
Subject: [PATCH] [analyzer] Accept C library functions from the `std`
namespace
Previously, the function `isCLibraryFunction()` and logic relying on it
only accepted functions that are declared directly within a TU (i.e. not
in a namespace or a class). However C++ headers like <cstdlib> declare
many C standard library functions within the namespace `std`, so this
commit ensures that functions within the namespace `std` are also
accepted.
After this commit it will be possible to match functions like `malloc` or
`free` with `CallDescription::Mode::CLibrary`.
---
.../StaticAnalyzer/Core/PathSensitive/CallDescription.h | 8 ++------
clang/lib/StaticAnalyzer/Core/CheckerContext.cpp | 9 ++++++---
2 files changed, 8 insertions(+), 9 deletions(-)
diff --git
a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h
b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h
index 3432d2648633c2..7da65734a44cf3 100644
--- a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h
+++ b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h
@@ -41,12 +41,8 @@ class CallDescription {
/// - 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>.
+ /// (This mode only matches functions that are declared either directly
+ /// within a TU or in the `std::` namespace.)
CLibrary,
/// Matches "simple" functions that are not methods. (Static methods are
diff --git a/clang/lib/StaticAnalyzer/Core/CheckerContext.cpp
b/clang/lib/StaticAnalyzer/Core/CheckerContext.cpp
index d6d4cec9dd3d4d..c1ae9b441d98d1 100644
--- a/clang/lib/StaticAnalyzer/Core/CheckerContext.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CheckerContext.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/Analysis/AnalysisDeclContext.h"
#include "clang/Basic/Builtins.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/StringExtras.h"
@@ -87,9 +88,11 @@ bool CheckerContext::isCLibraryFunction(const FunctionDecl
*FD,
if (!II)
return false;
- // Look through 'extern "C"' and anything similar invented in the future.
- // If this function is not in TU directly, it is not a C library function.
- if (!FD->getDeclContext()->getRedeclContext()->isTranslationUnit())
+ // C library functions are either declared directly within a TU (the common
+ // case) or they are accessed through the namespace `std::` (when they are
+ // used in C++ via headers like <cstdlib>).
+ if (!FD->getDeclContext()->getRedeclContext()->isTranslationUnit() &&
+ !AnalysisDeclContext::isInStdNamespace(FD))
return false;
// If this function is not externally visible, it is not a C library
function.
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