Merge pull request #303 from iovisor/bblanco_dev

Improve json type support for misc struct/union types

src/cc/frontends/clang/b_frontend_action.cc

@@ -67,10 +67,7 @@ bool BMapDeclVisitor::VisitRecordDecl(RecordDecl *D) {
   result_ += "\", [";
   for (auto F : D->getDefinition()->fields()) {
     result_ += "[";
-    if (F->getType()->isPointerType())
-      result_ += "\"" + F->getName().str() + "\", \"unsigned long long\"";
-    else
-      TraverseDecl(F);
+    TraverseDecl(F);
     if (const ConstantArrayType *T = dyn_cast<ConstantArrayType>(F->getType()))
       result_ += ", [" + T->getSize().toString(10, false) + "]";
     if (F->isBitField())
@@ -79,9 +76,19 @@ bool BMapDeclVisitor::VisitRecordDecl(RecordDecl *D) {
   }
   if (!D->getDefinition()->field_empty())
     result_.erase(result_.end() - 2);
-  result_ += "]]";
+  result_ += "]";
+  if (D->isUnion())
+    result_ += ", \"union\"";
+  else if (D->isStruct())
+    result_ += ", \"struct\"";
+  result_ += "]";
   return true;
 }
+// pointer to anything should be treated as terminal, don't recurse further
+bool BMapDeclVisitor::VisitPointerType(const PointerType *T) {
+  result_ += "\"unsigned long long\"";
+  return false;
+}
 bool BMapDeclVisitor::VisitTagType(const TagType *T) {
   return TraverseDecl(T->getDecl()->getDefinition());
 }
@@ -510,22 +517,32 @@ bool BTypeVisitor::VisitVarDecl(VarDecl *Decl) {
       sscanf(un.release, "%d.%d.", &major, &minor);
     }
 
-    TableDesc table;
+    TableDesc table = {};
     table.name = Decl->getName();
 
     unsigned i = 0;
     for (auto F : RD->fields()) {
       size_t sz = C.getTypeSize(F->getType()) >> 3;
       if (F->getName() == "key") {
+        if (sz == 0) {
+          unsigned diag_id = C.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error,
+                                                                "invalid zero-sized leaf");
+          C.getDiagnostics().Report(F->getLocStart(), diag_id);
+          return false;
+        }
         table.key_size = sz;
         BMapDeclVisitor visitor(C, table.key_desc);
-        if (!visitor.TraverseType(F->getType()))
-          return false;
+        visitor.TraverseType(F->getType());
       } else if (F->getName() == "leaf") {
+        if (sz == 0) {
+          unsigned diag_id = C.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error,
+                                                                "invalid zero-sized leaf");
+          C.getDiagnostics().Report(F->getLocStart(), diag_id);
+          return false;
+        }
         table.leaf_size = sz;
         BMapDeclVisitor visitor(C, table.leaf_desc);
-        if (!visitor.TraverseType(F->getType()))
-          return false;
+        visitor.TraverseType(F->getType());
       } else if (F->getName() == "data") {
         table.max_entries = sz / table.leaf_size;
       }

src/cc/frontends/clang/b_frontend_action.h

@@ -49,6 +49,7 @@ class BMapDeclVisitor : public clang::RecursiveASTVisitor<BMapDeclVisitor> {
   bool VisitBuiltinType(const clang::BuiltinType *T);
   bool VisitTypedefType(const clang::TypedefType *T);
   bool VisitTagType(const clang::TagType *T);
+  bool VisitPointerType(const clang::PointerType *T);
  private:
   clang::ASTContext &C;
   std::string &result_;

src/python/bcc/__init__.py

@@ -518,7 +518,13 @@ class BPF(object):
                     fields.append((t[0], BPF._decode_table_type(t[1]), t[2]))
             else:
                 raise Exception("Failed to decode type %s" % str(t))
-        cls = type(str(desc[0]), (ct.Structure,), dict(_fields_=fields))
+        base = ct.Structure
+        if len(desc) > 2:
+            if desc[2] == u"union":
+                base = ct.Union
+            elif desc[2] == u"struct":
+                base = ct.Structure
+        cls = type(str(desc[0]), (base,), dict(_fields_=fields))
         return cls
 
     def get_table(self, name, keytype=None, leaftype=None):

tests/cc/test_clang.py

@@ -247,7 +247,7 @@ int kprobe____kmalloc(struct pt_regs *ctx, size_t size) {
     if (leaf)
         leaf->size += size;
     return 0;
-}""", debug=4)
+}""")
 
     def test_unop_probe_read(self):
         text = """
@@ -263,5 +263,29 @@ int trace_entry(struct pt_regs *ctx, struct request *req) {
         b = BPF(text=text)
         fn = b.load_func("trace_entry", BPF.KPROBE)
 
+    def test_complex_leaf_types(self):
+        text = """
+struct list;
+struct list {
+  struct list *selfp;
+  struct list *another_selfp;
+  struct list *selfp_array[2];
+};
+struct empty {
+};
+union emptyu {
+  struct empty *em1;
+  struct empty em2;
+  struct empty em3;
+  struct empty em4;
+};
+BPF_TABLE("array", int, struct list, t1, 1);
+BPF_TABLE("array", int, struct list *, t2, 1);
+BPF_TABLE("array", int, union emptyu, t3, 1);
+"""
+        b = BPF(text=text)
+        import ctypes
+        self.assertEqual(ctypes.sizeof(b["t3"].Leaf), 8)
+
 if __name__ == "__main__":
     main()