-/// MCValue - This represents an "assembler immediate". In its most general
-/// form, this can hold "SymbolA - SymbolB + imm64". Not all targets supports
-/// relocations of this general form, but we need to represent this anyway.
+/// MCValue - This represents an "assembler immediate". In its most
+/// general form, this can hold ":Kind:(SymbolA - SymbolB + imm64)".
+/// Not all targets supports relocations of this general form, but we
+/// need to represent this anyway.
+///
+/// In general both SymbolA and SymbolB will also have a modifier
+/// analogous to the top-level Kind. Current targets are not expected
+/// to make use of both though. The choice comes down to whether
+/// relocation modifiers apply to the closest symbol or the whole
+/// expression.