go/ssa: add position info to all Load/Store instructions
Was originally https://codereview.appspot.com/92880043/ by Richard Musiol.
Change-Id: If0b22cf962b94ef44edbac28a5e5af4acb950991
Reviewed-on: https://go-review.googlesource.com/2174
Reviewed-by: Robert Griesemer <gri@golang.org>
diff --git a/go/ssa/ssa.go b/go/ssa/ssa.go
index bc5e9da..406611e 100644
--- a/go/ssa/ssa.go
+++ b/go/ssa/ssa.go
@@ -564,8 +564,12 @@
// and a boolean indicating the success of the receive. The
// components of the tuple are accessed using Extract.
//
-// Pos() returns the ast.UnaryExpr.OpPos or ast.RangeStmt.TokPos (for
-// ranging over a channel), if explicit in the source.
+// Pos() returns the ast.UnaryExpr.OpPos, if explicit in the source.
+// For receive operations (ARROW) implicit in ranging over a channel,
+// Pos() returns the ast.RangeStmt.For.
+// For implicit memory loads (STAR), Pos() returns the position of the
+// most closely associated source-level construct; the details are not
+// specified.
//
// Example printed form:
// t0 = *x
@@ -1162,7 +1166,10 @@
// The Store instruction stores Val at address Addr.
// Stores can be of arbitrary types.
//
-// Pos() returns the ast.StarExpr.Star, if explicit in the source.
+// Pos() returns the position of the source-level construct most closely
+// associated with the memory store operation.
+// Since implicit memory stores are numerous and varied and depend upon
+// implementation choices, the details are not specified.
//
// Example printed form:
// *x = y
