Swift: Support MAD tuple content flow.

Author: geoffw0

swift/ql/lib/codeql/swift/dataflow/ExternalFlow.qll

@@ -476,18 +476,25 @@ private predicate parseField(AccessPathToken c, Content::FieldContent f) {
   )
 }
 
-private predicate parseEnum(AccessPathToken c, Content::EnumContent f) {
+private predicate parseTuple(AccessPathToken c, Content::TupleContent t) {
+  c.getName() = "TupleElement" and
+  t.getIndex() = c.getAnArgument().toInt()
+}
+
+private predicate parseEnum(AccessPathToken c, Content::EnumContent e) {
   c.getName() = "EnumElement" and
-  c.getAnArgument() = f.getSignature()
+  c.getAnArgument() = e.getSignature()
   or
   c.getName() = "OptionalSome" and
-  f.getSignature() = "some:0"
+  e.getSignature() = "some:0"
 }
 
 /** Holds if the specification component parses as a `Content`. */
 predicate parseContent(AccessPathToken component, Content content) {
   parseField(component, content)
   or
+  parseTuple(component, content)
+  or
   parseEnum(component, content)
   or
   component.getName() = "ArrayElement" and

swift/ql/lib/codeql/swift/dataflow/internal/FlowSummaryImplSpecific.qll

@@ -110,6 +110,11 @@ private string getContentSpecific(ContentSet cs) {
     result = "Field[" + c.getField().getName() + "]"
   )
   or
+  exists(Content::TupleContent c |
+    cs.isSingleton(c) and
+    result = "TupleElement[" + c.getIndex().toString() + "]"
+  )
+  or
   exists(Content::EnumContent c |
     cs.isSingleton(c) and
     result = "EnumElement[" + c.getSignature() + "]"

swift/ql/test/library-tests/dataflow/dataflow/DataFlow.expected

@@ -182,13 +182,17 @@ edges
 | test.swift:369:13:369:13 | t [Tuple element at index 1] | test.swift:369:13:369:15 | .1 |
 | test.swift:369:13:369:15 | .1 | test.swift:369:12:369:19 | (...) [Tuple element at index 0] |
 | test.swift:375:14:375:26 | (...) [Tuple element at index 1] | test.swift:376:30:376:30 | t1 [Tuple element at index 1] |
+| test.swift:375:14:375:26 | (...) [Tuple element at index 1] | test.swift:377:30:377:30 | t1 [Tuple element at index 1] |
 | test.swift:375:14:375:26 | (...) [Tuple element at index 1] | test.swift:380:15:380:15 | t1 [Tuple element at index 1] |
 | test.swift:375:18:375:25 | call to source() | test.swift:375:14:375:26 | (...) [Tuple element at index 1] |
 | test.swift:376:14:376:32 | call to tupleShiftLeft1(_:) [Tuple element at index 0] | test.swift:381:15:381:15 | t2 [Tuple element at index 0] |
 | test.swift:376:30:376:30 | t1 [Tuple element at index 1] | test.swift:368:22:368:36 | t [Tuple element at index 1] |
 | test.swift:376:30:376:30 | t1 [Tuple element at index 1] | test.swift:376:14:376:32 | call to tupleShiftLeft1(_:) [Tuple element at index 0] |
+| test.swift:377:14:377:32 | call to tupleShiftLeft2(_:) [Tuple element at index 0] | test.swift:383:15:383:15 | t3 [Tuple element at index 0] |
+| test.swift:377:30:377:30 | t1 [Tuple element at index 1] | test.swift:377:14:377:32 | call to tupleShiftLeft2(_:) [Tuple element at index 0] |
 | test.swift:380:15:380:15 | t1 [Tuple element at index 1] | test.swift:380:15:380:18 | .1 |
 | test.swift:381:15:381:15 | t2 [Tuple element at index 0] | test.swift:381:15:381:18 | .0 |
+| test.swift:383:15:383:15 | t3 [Tuple element at index 0] | test.swift:383:15:383:18 | .0 |
 | test.swift:394:16:394:21 | v | test.swift:394:61:394:61 | v |
 | test.swift:394:61:394:61 | v | test.swift:394:45:394:62 | call to ... [mySingle:0] |
 | test.swift:396:18:396:23 | v | test.swift:396:59:396:59 | v |
@@ -607,10 +611,14 @@ nodes
 | test.swift:375:18:375:25 | call to source() | semmle.label | call to source() |
 | test.swift:376:14:376:32 | call to tupleShiftLeft1(_:) [Tuple element at index 0] | semmle.label | call to tupleShiftLeft1(_:) [Tuple element at index 0] |
 | test.swift:376:30:376:30 | t1 [Tuple element at index 1] | semmle.label | t1 [Tuple element at index 1] |
+| test.swift:377:14:377:32 | call to tupleShiftLeft2(_:) [Tuple element at index 0] | semmle.label | call to tupleShiftLeft2(_:) [Tuple element at index 0] |
+| test.swift:377:30:377:30 | t1 [Tuple element at index 1] | semmle.label | t1 [Tuple element at index 1] |
 | test.swift:380:15:380:15 | t1 [Tuple element at index 1] | semmle.label | t1 [Tuple element at index 1] |
 | test.swift:380:15:380:18 | .1 | semmle.label | .1 |
 | test.swift:381:15:381:15 | t2 [Tuple element at index 0] | semmle.label | t2 [Tuple element at index 0] |
 | test.swift:381:15:381:18 | .0 | semmle.label | .0 |
+| test.swift:383:15:383:15 | t3 [Tuple element at index 0] | semmle.label | t3 [Tuple element at index 0] |
+| test.swift:383:15:383:18 | .0 | semmle.label | .0 |
 | test.swift:394:16:394:21 | v | semmle.label | v |
 | test.swift:394:45:394:62 | call to ... [mySingle:0] | semmle.label | call to ... [mySingle:0] |
 | test.swift:394:61:394:61 | v | semmle.label | v |
@@ -944,6 +952,7 @@ subpaths
 | test.swift:364:15:364:15 | b | test.swift:351:31:351:38 | call to source() | test.swift:364:15:364:15 | b | result |
 | test.swift:380:15:380:18 | .1 | test.swift:375:18:375:25 | call to source() | test.swift:380:15:380:18 | .1 | result |
 | test.swift:381:15:381:18 | .0 | test.swift:375:18:375:25 | call to source() | test.swift:381:15:381:18 | .0 | result |
+| test.swift:383:15:383:18 | .0 | test.swift:375:18:375:25 | call to source() | test.swift:383:15:383:18 | .0 | result |
 | test.swift:428:19:428:19 | a | test.swift:422:19:422:26 | call to source() | test.swift:428:19:428:19 | a | result |
 | test.swift:437:19:437:19 | x | test.swift:422:19:422:26 | call to source() | test.swift:437:19:437:19 | x | result |
 | test.swift:453:19:453:19 | b | test.swift:444:26:444:33 | call to source() | test.swift:453:19:453:19 | b | result |

swift/ql/test/library-tests/dataflow/dataflow/test.swift

@@ -380,7 +380,7 @@ func testTuples3() {
     sink(arg: t1.1) // $ flow=375
     sink(arg: t2.0) // $ flow=375
     sink(arg: t2.1)
-    sink(arg: t3.0) // $ MISSING: flow=375
+    sink(arg: t3.0) // $ flow=375
     sink(arg: t3.1)
 }