sarif — archive

RE: [sarif] #401: Improved design of address object design

From: Laurence Golding
To: [email protected]
Date: Mon, 29 Apr 2019 20:21:00 -0000

There s a problem with relativeAddress , though. Here s what I currently have: 3.32.4 Relative address calculation Each address object has an associated value called its relative address which is the offset of the address from the address of the top-most object in its parent chain 3.32.7 relativeAddress property If parentIndex ( 3.32.13 ) is present, an address object MAY contain a property named relativeAddress whose value is an integer containing the relative address (see 3.32.4 ) of thisObject . If parentIndex is absent, then relativeAddress SHALL be absent. If relativeAddress is absent, it SHALL default to -1, which is otherwise not a valid value for this property . That s wrong. If your top-most address is a downward-growing stack, relativeAddress can be negative. And unlike offsetFromParent , we can t say (I mean, we can , but don t think we should) that relativeAddress SHALL be present if parentIndex is present, so we can t use 0 as the default. Ideas? I m going to have lunch now. Back in a while. Larry From: [email protected] <[email protected]> On Behalf Of Larry Golding (Myriad Consulting Inc) Sent: Monday, April 29, 2019 12:59 PM To: Michael Fanning <[email protected]>; James Kupsch <[email protected]>; OASIS SARIF TC Discussion List <[email protected]> Subject: RE: [sarif] #401: Improved design of address object design I approve this message! Much better than my solution. From: Michael Fanning < [email protected] > Sent: Monday, April 29, 2019 12:56 PM To: James Kupsch < [email protected] >; Larry Golding (Myriad Consulting Inc) < [email protected] >; OASIS SARIF TC Discussion List < [email protected] > Subject: RE: [sarif] #401: Improved design of address object design Here s my suggestion: For address.length, use a sentinel value of 0 meaning not provided . This makes sense, as Jim noted, a 0 length memory address isn t sensible. You don t posit describing an insertion point in memory that shoves everything to the right.