fix map a type parsing issue for export/extern types

Fix issue iovisor#1562. Currently, bcc allows a map defined in one module and used in the same or a different module. At tests/python directory, test_clang.py and test_shared_table.py have such an example. ... b1 = BPF(text="""BPF_TABLE_PUBLIC("hash", int, int, table1, 10);""") b2 = BPF(text="""BPF_TABLE("extern", int, int, table1, 10);""") t = b2["table"] ... With current implementation, the map key/value types are parsed twice, resulting a type "int int" instead of "int". When type is retrieved through `t = b2["table"]`, python decoding error will appear. The issue is fixed by preventing the second map key/value type parsing if the map is `extern`. Also add `t = b2["table"]` so the issue will be triggered if bcc clang frontend fix is not there. Signed-off-by: Yonghong Song <yhs@fb.com>
andyfangdz · Jan 29, 2018 · 96354c6 · 96354c6
1 parent 5d415c3
commit 96354c6
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diff --git a/src/cc/frontends/clang/b_frontend_action.cc b/src/cc/frontends/clang/b_frontend_action.cc
@@ -778,7 +778,8 @@ bool BTypeVisitor::VisitVarDecl(VarDecl *Decl) {
       return false;
     }
 
-    fe_.table_storage().VisitMapType(table, C, key_type, leaf_type);
+    if (!table.is_extern)
+      fe_.table_storage().VisitMapType(table, C, key_type, leaf_type);
     fe_.table_storage().Insert(local_path, move(table));
   } else if (const PointerType *P = Decl->getType()->getAs<PointerType>()) {
     // if var is a pointer to a packet type, clone the annotation into the var

diff --git a/tests/python/test_clang.py b/tests/python/test_clang.py
@@ -400,6 +400,7 @@ def test_cflags(self):
     def test_exported_maps(self):
         b1 = BPF(text="""BPF_TABLE_PUBLIC("hash", int, int, table1, 10);""")
         b2 = BPF(text="""BPF_TABLE("extern", int, int, table1, 10);""")
+        t = b2["table1"]
 
     def test_syntax_error(self):
         with self.assertRaises(Exception):