[clang-include-cleaner] Make cleanup attr report expr location (#140233)

Instead of reporting the location of the attribute, let's report the
location of the function reference that's passed to the cleanup
attribute as the first argument. This is required as the attribute might
be coming from a macro which means clang-include-cleaner skips the use
as it gets attributed to the header file declaringt the macro and not to
the main file.

To make this work, we have to add a fake argument to the CleanupAttr
constructor so we can pass in the original Expr alongside the function
declaration.

Fixes #140212

Author: DaanDeMeyer

clang-tools-extra/include-cleaner/lib/WalkAST.cpp

@@ -322,7 +322,7 @@ class ASTWalker : public RecursiveASTVisitor<ASTWalker> {
   }
 
   bool VisitCleanupAttr(CleanupAttr *attr) {
-    report(attr->getLocation(), attr->getFunctionDecl());
+    report(attr->getArgLoc(), attr->getFunctionDecl());
     return true;
   }
 

clang-tools-extra/include-cleaner/unittests/WalkASTTest.cpp

@@ -573,7 +573,7 @@ TEST(WalkAST, OperatorNewDelete) {
 
 TEST(WalkAST, CleanupAttr) {
   testWalk("void* $explicit^freep(void *p);",
-           "void foo() { __attribute__((^__cleanup__(freep))) char* x = 0; }");
+           "void foo() { __attribute__((__cleanup__(^freep))) char* x = 0; }");
 }
 
 } // namespace

clang/include/clang/Basic/Attr.td

@@ -1354,6 +1354,17 @@ def Cleanup : InheritableAttr {
   let Args = [DeclArgument<Function, "FunctionDecl">];
   let Subjects = SubjectList<[LocalVar]>;
   let Documentation = [CleanupDocs];
+  // FIXME: DeclArgument should be reworked to also store the
+  // Expr instead of adding attr specific hacks like the following.
+  // See the discussion in https://github.com/llvm/llvm-project/pull/14023.
+  let AdditionalMembers = [{
+private:
+    SourceLocation ArgLoc;
+
+public:
+    void setArgLoc(const SourceLocation &Loc) { ArgLoc = Loc; }
+    auto getArgLoc() const { return ArgLoc; }
+  }];
 }
 
 def CmseNSEntry : InheritableAttr, TargetSpecificAttr<TargetARM> {
@@ -4815,7 +4826,7 @@ def HLSLResourceBinding: InheritableAttr {
       void setImplicitBindingOrderID(uint32_t Value) {
         ImplicitBindingOrderID = Value;
       }
-      bool hasImplicitBindingOrderID() const { 
+      bool hasImplicitBindingOrderID() const {
         return ImplicitBindingOrderID.has_value();
       }
       uint32_t getImplicitBindingOrderID() const {

clang/lib/Sema/SemaDeclAttr.cpp

@@ -3620,7 +3620,9 @@ static void handleCleanupAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
     return;
   }
 
-  D->addAttr(::new (S.Context) CleanupAttr(S.Context, AL, FD));
+  auto *attr = ::new (S.Context) CleanupAttr(S.Context, AL, FD);
+  attr->setArgLoc(E->getExprLoc());
+  D->addAttr(attr);
 }
 
 static void handleEnumExtensibilityAttr(Sema &S, Decl *D,