使用 libclang 查找匿名枚举

Question

有没有一种方法可以使用 libclang 检测匿名枚举而不依赖拼写名称中的文本？

python 绑定到 libclang include functionality to detect whether C/C++ structs or unions are anonymous using clang.cindex.Cursor.is_anonymous, which ends up calling clang_Cursor_isAnonymous。

以下示例演示了该问题。

import sys
from clang.cindex import *

def nodeinfo(n):
    return (n.kind, n.is_anonymous(), n.spelling, n.type.spelling)

idx = Index.create()

# translation unit parsed correctly
tu = idx.parse(sys.argv[1], ['-std=c++11'])
assert(len(tu.diagnostics) == 0)

for n in tu.cursor.walk_preorder():
    if n.kind == CursorKind.STRUCT_DECL and n.is_anonymous():
        print nodeinfo(n)
    if n.kind == CursorKind.UNION_DECL and n.is_anonymous():
        print nodeinfo(n)
    if n.kind == CursorKind.ENUM_DECL:
        if n.is_anonymous():
            print nodeinfo(n)
        else:
            print 'INCORRECT', nodeinfo(n)

当运行在 sample.cpp

enum
{
    VAL = 1
};

struct s
{
    struct {};
    union
    {
        int x;
        float y;
    };
};

给出：

INCORRECT (CursorKind.ENUM_DECL, False, '', '(anonymous enum at sample1.cpp:1:1)')
(CursorKind.STRUCT_DECL, True, '', 's::(anonymous struct at sample1.cpp:8:5)')
(CursorKind.UNION_DECL, True, '', 's::(anonymous union at sample1.cpp:9:5)')

Answer 1

不幸的是，clang_Cursor_isAnonymous 仅适用于结构和联合，您可以从 tools/libclang/CXType.cpp

中的 clang 源代码中看到这一点

unsigned clang_Cursor_isAnonymous(CXCursor C){
  if (!clang_isDeclaration(C.kind))
    return 0;
  const Decl *D = cxcursor::getCursorDecl(C);
  if (const RecordDecl *FD = dyn_cast_or_null<RecordDecl>(D))
    return FD->isAnonymousStructOrUnion();
  return 0;
}

因此回退到 clang.cindex.Cursor.is_anonymous 中的 conf.lib.clang_Cursor_isAnonymous 并没有什么新的，因为已经根据 FIELD_DECL 检查了游标类型（这仅适用于结构和联合）

def is_anonymous(self):
        """
        Check if the record is anonymous.
        """
        if self.kind == CursorKind.FIELD_DECL:
            return self.type.get_declaration().is_anonymous()
        return conf.lib.clang_Cursor_isAnonymous(self)

您可以尝试提取当前元素的标识符（样本中的n）并检查它是否存在或为空

使用 libclang 查找匿名枚举

Finding anonymous enums with libclang

c

c++

python

clang

libclang