Revert "Reapply "[analyzer] Accept C library functions from the std…

… namespace"" This reverts commit e48d5a8. Fails to build on x86-64 w/gcc version 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04) with the following message: ../llvm-project/clang/unittests/StaticAnalyzer/IsCLibraryFunctionTest.cpp:41:28: error: declaration of ‘std::unique_ptr<clang::ASTUnit> IsCLibraryFunctionTest::ASTUnit’ changes meaning of ‘ASTUnit’ [-fpermissive] 41 | std::unique_ptr<ASTUnit> ASTUnit; | ^~~~~~~ In file included from ../llvm-project/clang/unittests/StaticAnalyzer/IsCLibraryFunctionTest.cpp:4: ../llvm-project/clang/include/clang/Frontend/ASTUnit.h:89:7: note: ‘ASTUnit’ declared here as ‘class clang::ASTUnit’ 89 | class ASTUnit { | ^~~~~~~
llvm · Mar 13, 2024 · 13ccaf9 · 13ccaf9
1 parent 35f5cae
commit 13ccaf9
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Showing 5 changed files with 9 additions and 93 deletions.
diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h
@@ -41,8 +41,12 @@ 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().
-    /// (This mode only matches functions that are declared either directly
-    /// within a TU or in the namespace `std`.)
+    /// 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,
 
     /// 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
@@ -87,11 +87,9 @@ bool CheckerContext::isCLibraryFunction(const FunctionDecl *FD,
   if (!II)
     return false;
 
-  // 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>).
-  const DeclContext *DC = FD->getDeclContext()->getRedeclContext();
-  if (!(DC->isTranslationUnit() || DC->isStdNamespace()))
+  // 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())
     return false;
 
   // If this function is not externally visible, it is not a C library function.

diff --git a/clang/unittests/StaticAnalyzer/CMakeLists.txt b/clang/unittests/StaticAnalyzer/CMakeLists.txt
@@ -11,7 +11,6 @@ add_clang_unittest(StaticAnalysisTests
   CallEventTest.cpp
   ConflictingEvalCallsTest.cpp
   FalsePositiveRefutationBRVisitorTest.cpp
-  IsCLibraryFunctionTest.cpp
   NoStateChangeFuncVisitorTest.cpp
   ParamRegionTest.cpp
   RangeSetTest.cpp

diff --git a/clang/unittests/StaticAnalyzer/IsCLibraryFunctionTest.cpp b/clang/unittests/StaticAnalyzer/IsCLibraryFunctionTest.cpp
diff --git a/llvm/utils/gn/secondary/clang/unittests/StaticAnalyzer/BUILD.gn b/llvm/utils/gn/secondary/clang/unittests/StaticAnalyzer/BUILD.gn
@@ -19,7 +19,6 @@ unittest("StaticAnalysisTests") {
     "CallEventTest.cpp",
     "ConflictingEvalCallsTest.cpp",
     "FalsePositiveRefutationBRVisitorTest.cpp",
-    "IsCLibraryFunctionTest.cpp",
     "NoStateChangeFuncVisitorTest.cpp",
     "ParamRegionTest.cpp",
     "RangeSetTest.cpp",