An extremely hacky version of transparent_union support; it isn't
anywhere near correct in terms of missing cases and missing
diagnostics, but it's good enough to handle the uses in the
Linux system headers, which are currently a constant pain for compiling
applications on Linux.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@55621 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index 95d2112..9c90306 100644
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -694,6 +694,9 @@
"'%0' attribute invalid on this declaration, requires typedef or value")
DIAG(warn_attribute_nonnull_no_pointers, WARNING,
"'nonnull' attribute applied to function with no pointer arguments")
+DIAG(warn_transparent_union_nonpointer, WARNING,
+ "'transparent_union' attribute support incomplete; only supported for"
+ "pointer unions")
// Clang-Specific Attributes
DIAG(err_attribute_iboutlet_non_ivar, ERROR,
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index eb9888e..b5737d8 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -725,19 +725,34 @@
return;
}
- TypeDecl *decl = dyn_cast<TypeDecl>(d);
-
- if (!decl || !S.Context.getTypeDeclType(decl)->isUnionType()) {
+ // FIXME: This shouldn't be restricted to typedefs
+ TypedefDecl *TD = dyn_cast<TypedefDecl>(d);
+ if (!TD || !TD->getUnderlyingType()->isUnionType()) {
S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type,
"transparent_union", "union");
return;
}
- //QualType QTy = Context.getTypeDeclType(decl);
- //const RecordType *Ty = QTy->getAsUnionType();
+ RecordDecl* RD = TD->getUnderlyingType()->getAsUnionType()->getDecl();
-// FIXME
-// Ty->addAttr(new TransparentUnionAttr());
+ // FIXME: Should we do a check for RD->isDefinition()?
+
+ // FIXME: This isn't supposed to be restricted to pointers, but otherwise
+ // we might silently generate incorrect code; see following code
+ for (int i = 0; i < RD->getNumMembers(); i++) {
+ if (!RD->getMember(i)->getType()->isPointerType()) {
+ S.Diag(Attr.getLoc(), diag::warn_transparent_union_nonpointer);
+ return;
+ }
+ }
+
+ // FIXME: This is a complete hack; we should be properly propagating
+ // transparent_union through Sema. That said, this is close enough to
+ // correctly compile all the common cases of transparent_union without
+ // errors or warnings
+ QualType NewTy = S.Context.VoidPtrTy;
+ NewTy.addConst();
+ TD->setUnderlyingType(NewTy);
}
static void HandleAnnotateAttr(Decl *d, const AttributeList &Attr, Sema &S) {
diff --git a/test/Sema/transparent-union-pointer.c b/test/Sema/transparent-union-pointer.c
new file mode 100644
index 0000000..58597b1
--- /dev/null
+++ b/test/Sema/transparent-union-pointer.c
@@ -0,0 +1,14 @@
+// RUN: clang %s -fsyntax-only -verify
+
+typedef union {
+ union wait *__uptr;
+ int *__iptr;
+} __WAIT_STATUS __attribute__ ((__transparent_union__));
+
+extern int wait (__WAIT_STATUS __stat_loc);
+
+void fastcgi_cleanup() {
+ int status = 0;
+ wait(&status);
+}
+