c++clangabstract-syntax-treeoclintlibtooling

OCLint ASTMatcher rule. Matching NS_ENUM


I am trying to create an OCLint rule that matches both typedef enum and typedef NS_ENUM declarations, with little success. I have an Objective-C file (TestClass.m) with the following enum declarations in it:

typedef NS_ENUM(NSInteger, TestEnum) {
    TestEnumNone,
    TestEnumSome,
    TestEnumAll
};

typedef enum {
    othertestvalue = 0,
    othertestvalue1,
    othertestvalue2
} OtherTestEnum;

Dumping the AST with this command:

clang -Xclang -ast-dump -fsyntax-only Classes/TestClass.m -- | grep Enum

Gives me this output containing this:

|-TypedefDecl 0x7f9d3accd630 <col:1, col:28> col:28 TestEnum 'enum TestEnum':'enum TestEnum'
|-EnumDecl 0x7f9d3accd6a8 prev 0x7f9d3accd530 </System/Library/Frameworks/CoreFoundation.framework/Headers/CFAvailability.h:171:57, Classes/TestClass.m:71:1> line:67:28 TestEnum 'NSInteger':'long'
| |-EnumConstantDecl 0x7f9d3accd738 <line:68:5> col:5 TestEnumNone 'NSInteger':'long'
| |-EnumConstantDecl 0x7f9d3accd788 <line:69:5> col:5 TestEnumSome 'NSInteger':'long'
| `-EnumConstantDecl 0x7f9d3accd7d8 <line:70:5> col:5 TestEnumAll 'NSInteger':'long'
|-EnumDecl 0x7f9d3accd828 <line:73:9, line:77:1> line:73:9
| |-EnumConstantDecl 0x7f9d3accd900 <line:74:5, col:22> col:5 othertestvalue 'int'
| |-EnumConstantDecl 0x7f9d3accd950 <line:75:5> col:5 othertestvalue1 'int'
| `-EnumConstantDecl 0x7f9d3accd9a0 <line:76:5> col:5 othertestvalue2 'int'
|-TypedefDecl 0x7f9d3accda40 <line:73:1, line:77:3> col:3 OtherTestEnum 'enum OtherTestEnum':'OtherTestEnum'

I have an ASTMatcherRule (ObjCNsEnumRule) where I am trying to match both typedef enum as well as typedef NS_ENUM Here is the code for that:

#include "oclint/AbstractASTMatcherRule.h"
#include "oclint/RuleSet.h"

using namespace std;
using namespace clang;
using namespace clang::ast_matchers;
using namespace oclint;

class ObjCNsEnumRuleRule : public AbstractASTMatcherRule
{
public:
virtual const string name() const override
{
    return "obj c ns enum rule";
}

virtual int priority() const override
{
    return 3;
}

virtual void callback(const MatchFinder::MatchResult &result) override
{
  const EnumDecl *enumDecl = result.Nodes.getNodeAs<EnumDecl>("enum");
  if (enumDecl) {
    addViolation(enumDecl, this, "Found enum");
  }
}

virtual void setUpMatcher() override
{
  addMatcher(enumDecl().bind("enum"));
}

};

static RuleSet rules(new ObjCNsEnumRuleRule());

However, when I run this rule, I only get the output for the typedef enum declaration.

Classes/TestClass.m:73:9: obj c ns enum rule P3 Found enum

What am I doing wrong here? Both enums show up in the AST dump, but only one matches in the OCLint rule.

Edit

I think this may have to do with the AST dump showing the EnumDecl for the NS_ENUM as defined in a different source file (probably because of the NS_ENUM macro), as I can match the typedef, but not the enumdecl.


Solution

  • It doesn't look like there is currently a way to do this in oclint. Macros are not exposed to oclint rules for ASTVisitor or ASTMatcher rules. See here: https://github.com/oclint/oclint/issues/148

    I ended up implementing this as a simple SourceCodeReaderRule, like this:

    #include "oclint/AbstractSourceCodeReaderRule.h"
    #include "oclint/RuleSet.h"
    #include <iostream>
    #include <string>
    #include <regex>
    
    using namespace std;
    using namespace oclint;
    
    class TypedefEnumStatementRule : public AbstractSourceCodeReaderRule
    {
    public:
    virtual const string name() const override {
        return "typedef enum statement";
    }
    
    virtual int priority() const override {
        return 1;
    }
    
    virtual void eachLine(int lineNumber, string line) override {
        regex rgx("typedef\\senum");
        smatch match;
        if (regex_search(line, rgx, regex_constants::match_continuous)) {
            string description = "Enums should not be declared with 'typedef enum' use 'typedef NS_ENUM' instead";
            addViolation(lineNumber, 1, lineNumber, 1, this, description);
        }
    }
    };
    
    static RuleSet rules(new TypedefEnumStatementRule());