yonghong-song updated this revision to Diff 374057.
yonghong-song added a comment.
- change to use DeclOrTypeAttr in Attr.td to indicate the attribute can be used
for declarations or type qualifier.
- add explanation of why the change in AttrDocs.td and the test.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D110116/new/
https://reviews.llvm.org/D110116
Files:
clang/include/clang/Basic/Attr.td
clang/include/clang/Basic/AttrDocs.td
clang/lib/AST/TypePrinter.cpp
clang/lib/Sema/SemaType.cpp
clang/test/Sema/attr-btf_tag.c
Index: clang/test/Sema/attr-btf_tag.c
===================================================================
--- clang/test/Sema/attr-btf_tag.c
+++ clang/test/Sema/attr-btf_tag.c
@@ -40,3 +40,11 @@
int __tag1 foo(struct t1 *arg __tag1, struct t2 *arg2) {
return arg->a + arg2->a;
}
+
+void * convert(long arg) {
+ /* FIXME: the attribute __tag1 is accepted but didn't really do type
conversion
+ * or enforce type checking. This is to permit linux kernel build with
btf_tag
+ * attribute.
+ */
+ return (void __tag1 *)arg;
+}
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -8127,6 +8127,12 @@
case ParsedAttr::IgnoredAttribute:
break;
+ case ParsedAttr::AT_BTFTag:
+ // FIXME: Linux kernel may also use this attribute for type casting
check,
+ // which clang doesn's support for now. Let us ignore them so linux
kernel
+ // build won't break.
+ attr.setUsedAsTypeAttr();
+ break;
case ParsedAttr::AT_MayAlias:
// FIXME: This attribute needs to actually be handled, but if we ignore
// it it breaks large amounts of Linux software.
Index: clang/lib/AST/TypePrinter.cpp
===================================================================
--- clang/lib/AST/TypePrinter.cpp
+++ clang/lib/AST/TypePrinter.cpp
@@ -1702,6 +1702,7 @@
case attr::UPtr:
case attr::AddressSpace:
case attr::CmseNSCall:
+ case attr::BTFTag:
llvm_unreachable("This attribute should have been handled already");
case attr::NSReturnsRetained:
Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -2019,6 +2019,9 @@
function, function parameter or variable declaration. If -g is specified,
the ``ARGUMENT`` info will be preserved in IR and be emitted to dwarf.
For BPF targets, the ``ARGUMENT`` info will be emitted to .BTF ELF section too.
+
+The attribute can also be used as a type qualifier. Right now it is accepted
+and silently ignored in order to permit linux kernel build with the attribute.
}];
}
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -1835,7 +1835,7 @@
let LangOpts = [COnly];
}
-def BTFTag : InheritableAttr {
+def BTFTag : DeclOrTypeAttr {
let Spellings = [Clang<"btf_tag">];
let Args = [StringArgument<"BTFTag">];
let Subjects = SubjectList<[Var, Function, Record, Field], ErrorDiag>;
Index: clang/test/Sema/attr-btf_tag.c
===================================================================
--- clang/test/Sema/attr-btf_tag.c
+++ clang/test/Sema/attr-btf_tag.c
@@ -40,3 +40,11 @@
int __tag1 foo(struct t1 *arg __tag1, struct t2 *arg2) {
return arg->a + arg2->a;
}
+
+void * convert(long arg) {
+ /* FIXME: the attribute __tag1 is accepted but didn't really do type conversion
+ * or enforce type checking. This is to permit linux kernel build with btf_tag
+ * attribute.
+ */
+ return (void __tag1 *)arg;
+}
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -8127,6 +8127,12 @@
case ParsedAttr::IgnoredAttribute:
break;
+ case ParsedAttr::AT_BTFTag:
+ // FIXME: Linux kernel may also use this attribute for type casting check,
+ // which clang doesn's support for now. Let us ignore them so linux kernel
+ // build won't break.
+ attr.setUsedAsTypeAttr();
+ break;
case ParsedAttr::AT_MayAlias:
// FIXME: This attribute needs to actually be handled, but if we ignore
// it it breaks large amounts of Linux software.
Index: clang/lib/AST/TypePrinter.cpp
===================================================================
--- clang/lib/AST/TypePrinter.cpp
+++ clang/lib/AST/TypePrinter.cpp
@@ -1702,6 +1702,7 @@
case attr::UPtr:
case attr::AddressSpace:
case attr::CmseNSCall:
+ case attr::BTFTag:
llvm_unreachable("This attribute should have been handled already");
case attr::NSReturnsRetained:
Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -2019,6 +2019,9 @@
function, function parameter or variable declaration. If -g is specified,
the ``ARGUMENT`` info will be preserved in IR and be emitted to dwarf.
For BPF targets, the ``ARGUMENT`` info will be emitted to .BTF ELF section too.
+
+The attribute can also be used as a type qualifier. Right now it is accepted
+and silently ignored in order to permit linux kernel build with the attribute.
}];
}
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -1835,7 +1835,7 @@
let LangOpts = [COnly];
}
-def BTFTag : InheritableAttr {
+def BTFTag : DeclOrTypeAttr {
let Spellings = [Clang<"btf_tag">];
let Args = [StringArgument<"BTFTag">];
let Subjects = SubjectList<[Var, Function, Record, Field], ErrorDiag>;
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
