每次内容主要出自文檔： “Clang” CFE Internals Manual
位址： http://clang.llvm.org/docs/InternalsManual.html
在這個文檔中，以簡明的的一個例子說明了如何按照這個方式在Clang中添加一個屬性。講的很清楚，我在這裡不再累述，隻是将例子中的部分代碼和文檔結合起來，一起展現給大家。
of adding a warning attribute.
(Beware that this hasn’t been reviewed/fixed by the people who designed theattributes system yet.)
Each attribute gets a def inheriting fromAttr or one of itssubclasses.InheritableAttr
means that the attribute also applies tosubsequent declarations of the same name.
Spellings lists the strings that can appear in__attribute__((here)) or[[here]].
All such strings will be synonymous. If you want to allow the[[]] C++11 syntax, you have to define a list ofNamespaces, which willlet users
write[[namespace::spelling]]. Using the empty string for anamespace will allow users to write just the spelling with no “::”.Attributes which
g++-4.8 accepts should also have a CXX11<"gnu","spelling"> spelling.
Subjects restricts what kinds of AST node to which this attribute canappertain (roughly, attach).
Args names the arguments the attribute takes, in order. IfArgs is
[StringArgument<"Arg1">,
IntArgument<"Arg2">] then__attribute__((myattribute("Hello",3))) will be a valid use.
add a case to the switch in ProcessNonInheritableDeclAttr() or
ProcessInheritableDeclAttr() forwarding to it.
If your attribute causes extra warnings to fire, define a
Spelling with “_”s replaced by “-“s. If you’reonly defining one diagnostic, you can skipDiagnosticGroups.td and useInGroup<DiagGroup<"your-attribute">>
Find an appropriate place in Clang to do whatever your attribute needs to do.Check for the attribute’s presence usingDecl::getAttr<YourAttr>().