xdrgen: XDR width for union types

Not yet complete.

The tool doesn't do any math yet. Thus, even though the maximum XDR
width of a union is the width of the union enumerator plus the width
of its largest arm, we're using the sum of all the elements of the
union for the moment.

This means that buffer size requirements are overestimated, and that
the generated maxsize macro cannot yet be used for determining data
element alignment in the XDR buffer.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/tools/net/sunrpc/xdrgen/xdr_ast.py b/tools/net/sunrpc/xdrgen/xdr_ast.py
index 8d53c889eee8d266baea1b01f42b8b7ab460d761..5233e73c7046a66821c15574ad99a2ccdb20adf5 100644 (file)
--- a/tools/net/sunrpc/xdrgen/xdr_ast.py
+++ b/tools/net/sunrpc/xdrgen/xdr_ast.py
@@ -450,9 +450,35 @@ class _XdrUnion(_XdrAst):
     cases: List[_XdrCaseSpec]
     default: _XdrDeclaration
 
+    def max_width(self) -> int:
+        """Return width of type in XDR_UNITS"""
+        max_width = 0
+        for case in self.cases:
+            if case.arm.max_width() > max_width:
+                max_width = case.arm.max_width()
+        if self.default:
+            if self.default.arm.max_width() > max_width:
+                max_width = self.default.arm.max_width()
+        return 1 + max_width
+
+    def symbolic_width(self) -> List:
+        """Return list containing XDR width of type's components"""
+        max_width = 0
+        for case in self.cases:
+            if case.arm.max_width() > max_width:
+                max_width = case.arm.max_width()
+                width = case.arm.symbolic_width()
+        if self.default:
+            if self.default.arm.max_width() > max_width:
+                max_width = self.default.arm.max_width()
+                width = self.default.arm.symbolic_width()
+        return symbolic_widths[self.discriminant.name] + width
+
     def __post_init__(self):
         structs.add(self.name)
         pass_by_reference.add(self.name)
+        max_widths[self.name] = self.max_width()
+        symbolic_widths[self.name] = self.symbolic_width()
 
 
 @dataclass