C#: Include CFG splits in Ssa::Definition::toString()

Just like syntax elements can be split in the control flow graph, so can SSA
definitions. To make this clear, and to make debugging easier, this commit
adds the splits as a prefix in the textual representation of SSA definitions.

Author: hvitved

csharp/ql/src/semmle/code/csharp/controlflow/ControlFlowGraph.qll

@@ -353,6 +353,12 @@ module ControlFlow {
         )
       }
 
+      /** Gets a comma-separated list of strings for each split in this node, if any. */
+      string getSplitsString() {
+        result = splits.toString() and
+        result != ""
+      }
+
       /** Gets a split for this control flow node, if any. */
       Split getASplit() {
         result = splits.getASplit()

csharp/ql/src/semmle/code/csharp/dataflow/SSA.qll

@@ -1975,6 +1975,25 @@ module Ssa {
 
   private import SsaImpl
 
+  private string getSplitString(Definition def) {
+    exists(BasicBlock bb, int i, ControlFlow::Node cfn |
+      definesAt(def, bb, i, _) and
+      result = cfn.(ControlFlow::Nodes::ElementNode).getSplitsString()
+    |
+      cfn = bb.getNode(i)
+      or
+      not exists(bb.getNode(i)) and
+      cfn = bb.getFirstNode()
+    )
+  }
+
+  private string getToStringPrefix(Definition def) {
+    result = "[" + getSplitString(def) + "] "
+    or
+    not exists(getSplitString(def)) and
+    result = ""
+  }
+
   /**
    * A static single assignment (SSA) definition. Either an explicit variable
    * definition (`ExplicitDefinition`), an implicit variable definition
@@ -2311,9 +2330,9 @@ module Ssa {
 
     override string toString() {
       if this.getADefinition() instanceof AssignableDefinitions::ImplicitParameterDefinition then
-        result = "SSA param(" + this.getSourceVariable() + ")"
+        result = getToStringPrefix(this) + "SSA param(" + this.getSourceVariable() + ")"
       else
-        result = "SSA def(" + this.getSourceVariable() + ")"
+        result = getToStringPrefix(this) + "SSA def(" + this.getSourceVariable() + ")"
     }
 
     override Location getLocation() {
@@ -2354,9 +2373,9 @@ module Ssa {
 
     override string toString() {
       if this.getSourceVariable().getAssignable() instanceof LocalScopeVariable then
-        result = "SSA capture def(" + this.getSourceVariable() + ")"
+        result = getToStringPrefix(this) + "SSA capture def(" + this.getSourceVariable() + ")"
       else
-        result = "SSA entry def(" + this.getSourceVariable() + ")"
+        result = getToStringPrefix(this) + "SSA entry def(" + this.getSourceVariable() + ")"
     }
 
     override Location getLocation() {
@@ -2391,7 +2410,7 @@ module Ssa {
     }
 
     override string toString() {
-      result = "SSA call def(" + getSourceVariable() + ")"
+      result = getToStringPrefix(this) + "SSA call def(" + getSourceVariable() + ")"
     }
 
     override Location getLocation() {
@@ -2410,7 +2429,7 @@ module Ssa {
     }
 
     override string toString() {
-      result = "SSA qualifier def(" + getSourceVariable() + ")"
+      result = getToStringPrefix(this) + "SSA qualifier def(" + getSourceVariable() + ")"
     }
 
     override Location getLocation() {
@@ -2435,7 +2454,7 @@ module Ssa {
     }
 
     override string toString() {
-      result = "SSA untracked def(" + getSourceVariable() + ")"
+      result = getToStringPrefix(this) + "SSA untracked def(" + getSourceVariable() + ")"
     }
 
     override Location getLocation() {
@@ -2497,7 +2516,7 @@ module Ssa {
     }
 
     override string toString() {
-      result = "SSA phi(" + getSourceVariable() + ")"
+      result = getToStringPrefix(this) + "SSA phi(" + getSourceVariable() + ")"
     }
 
     /*

csharp/ql/test/library-tests/dataflow/ssa/SsaAdjacentUncertainRead.expected

@@ -69,7 +69,7 @@ WARNING: Predicate getAFirstUncertainRead has been deprecated and may be removed
 | Capture.cs:236:9:236:12 | SSA call def(i) | Capture.cs:237:34:237:34 | access to local variable i |
 | Consistency.cs:7:25:7:25 | SSA param(b) | Consistency.cs:11:17:11:17 | access to parameter b |
 | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
-| Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
+| Consistency.cs:15:17:15:21 | [finally: exception(Exception)] SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
 | Consistency.cs:25:29:25:29 | SSA def(c) | Consistency.cs:26:13:26:13 | access to local variable c |
 | Consistency.cs:25:29:25:29 | SSA qualifier def(c.Field) | Consistency.cs:26:13:26:19 | access to field Field |
 | Consistency.cs:32:9:32:29 | SSA def(c) | Consistency.cs:33:9:33:9 | access to parameter c |
@@ -318,7 +318,7 @@ WARNING: Predicate getAFirstUncertainRead has been deprecated and may be removed
 | Test.cs:46:10:46:10 | SSA entry def(this.field) | Test.cs:56:13:56:17 | access to field field |
 | Test.cs:46:16:46:18 | SSA param(in) | Test.cs:48:13:48:15 | access to parameter in |
 | Test.cs:57:9:57:17 | SSA def(this.field) | Test.cs:58:13:58:17 | access to field field |
-| Test.cs:68:45:68:45 | SSA def(e) | Test.cs:70:17:70:17 | access to local variable e |
+| Test.cs:68:45:68:45 | [exception: DivideByZeroException] SSA def(e) | Test.cs:70:17:70:17 | access to local variable e |
 | Tuples.cs:10:9:10:54 | SSA def(b) | Tuples.cs:12:13:12:13 | access to local variable b |
 | Tuples.cs:10:9:10:54 | SSA def(s) | Tuples.cs:13:13:13:13 | access to local variable s |
 | Tuples.cs:10:9:10:54 | SSA def(x) | Tuples.cs:11:13:11:13 | access to local variable x |

csharp/ql/test/library-tests/dataflow/ssa/SsaDef.expected

@@ -84,7 +84,7 @@
 | Capture.cs:229:13:229:13 | i | Capture.cs:236:9:236:12 | SSA call def(i) |
 | Consistency.cs:7:25:7:25 | b | Consistency.cs:7:25:7:25 | SSA param(b) |
 | Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) |
-| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) |
+| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | [finally: exception(Exception)] SSA def(i) |
 | Consistency.cs:25:29:25:29 | c | Consistency.cs:25:29:25:29 | SSA def(c) |
 | Consistency.cs:26:13:26:19 | c.Field | Consistency.cs:25:29:25:29 | SSA qualifier def(c.Field) |
 | Consistency.cs:30:30:30:30 | c | Consistency.cs:32:9:32:29 | SSA def(c) |
@@ -342,7 +342,7 @@
 | Test.cs:46:29:46:32 | out | Test.cs:56:9:56:19 | SSA phi(out) |
 | Test.cs:56:13:56:17 | this.field | Test.cs:46:10:46:10 | SSA entry def(this.field) |
 | Test.cs:56:13:56:17 | this.field | Test.cs:57:9:57:17 | SSA def(this.field) |
-| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | SSA def(e) |
+| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | [exception: DivideByZeroException] SSA def(e) |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:10:9:10:54 | SSA def(x) |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:14:9:14:32 | SSA def(x) |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:23:9:23:37 | SSA def(x) |

csharp/ql/test/library-tests/dataflow/ssa/SsaDefLastRead.expected

@@ -53,7 +53,7 @@
 | Capture.cs:229:13:229:13 | i | Capture.cs:236:9:236:12 | SSA call def(i) | Capture.cs:237:34:237:34 | access to local variable i |
 | Consistency.cs:7:25:7:25 | b | Consistency.cs:7:25:7:25 | SSA param(b) | Consistency.cs:11:17:11:17 | access to parameter b |
 | Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
-| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
+| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | [finally: exception(Exception)] SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
 | Consistency.cs:25:29:25:29 | c | Consistency.cs:25:29:25:29 | SSA def(c) | Consistency.cs:27:13:27:13 | access to local variable c |
 | Consistency.cs:26:13:26:19 | c.Field | Consistency.cs:25:29:25:29 | SSA qualifier def(c.Field) | Consistency.cs:27:13:27:19 | access to field Field |
 | Consistency.cs:44:11:44:11 | s | Consistency.cs:44:11:44:11 | SSA def(s) | Consistency.cs:46:13:46:13 | access to local variable s |
@@ -235,7 +235,7 @@
 | Test.cs:46:16:46:18 | in | Test.cs:46:16:46:18 | SSA param(in) | Test.cs:48:13:48:15 | access to parameter in |
 | Test.cs:56:13:56:17 | this.field | Test.cs:46:10:46:10 | SSA entry def(this.field) | Test.cs:56:13:56:17 | access to field field |
 | Test.cs:56:13:56:17 | this.field | Test.cs:57:9:57:17 | SSA def(this.field) | Test.cs:58:13:58:17 | access to field field |
-| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | SSA def(e) | Test.cs:70:17:70:17 | access to local variable e |
+| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | [exception: DivideByZeroException] SSA def(e) | Test.cs:70:17:70:17 | access to local variable e |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:10:9:10:54 | SSA def(x) | Tuples.cs:11:13:11:13 | access to local variable x |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:14:9:14:32 | SSA def(x) | Tuples.cs:15:13:15:13 | access to local variable x |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:23:9:23:37 | SSA def(x) | Tuples.cs:24:13:24:13 | access to local variable x |

csharp/ql/test/library-tests/dataflow/ssa/SsaExplicitDef.expected

@@ -56,7 +56,7 @@
 | Capture.cs:229:13:229:13 | i | Capture.cs:235:21:235:25 | SSA def(i) | Capture.cs:235:21:235:25 | ... = ... |
 | Consistency.cs:7:25:7:25 | b | Consistency.cs:7:25:7:25 | SSA param(b) | Consistency.cs:7:25:7:25 | b |
 | Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:15:17:15:21 | Int32 i = ... |
-| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:15:17:15:21 | Int32 i = ... |
+| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | [finally: exception(Exception)] SSA def(i) | Consistency.cs:15:17:15:21 | Int32 i = ... |
 | Consistency.cs:25:29:25:29 | c | Consistency.cs:25:29:25:29 | SSA def(c) | Consistency.cs:25:29:25:29 | Consistency c |
 | Consistency.cs:30:30:30:30 | c | Consistency.cs:32:9:32:29 | SSA def(c) | Consistency.cs:32:9:32:29 | ... = ... |
 | Consistency.cs:38:13:38:13 | i | Consistency.cs:39:28:39:32 | SSA def(i) | Consistency.cs:39:28:39:32 | ... = ... |
@@ -209,7 +209,7 @@
 | Test.cs:46:29:46:32 | out | Test.cs:50:13:50:20 | SSA def(out) | Test.cs:50:13:50:20 | ... = ... |
 | Test.cs:46:29:46:32 | out | Test.cs:54:13:54:20 | SSA def(out) | Test.cs:54:13:54:20 | ... = ... |
 | Test.cs:56:13:56:17 | this.field | Test.cs:57:9:57:17 | SSA def(this.field) | Test.cs:57:9:57:17 | ... = ... |
-| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | SSA def(e) | Test.cs:68:45:68:45 | DivideByZeroException e |
+| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | [exception: DivideByZeroException] SSA def(e) | Test.cs:68:45:68:45 | DivideByZeroException e |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:10:9:10:54 | SSA def(x) | Tuples.cs:10:9:10:54 | ... = ... |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:14:9:14:32 | SSA def(x) | Tuples.cs:14:9:14:32 | ... = ... |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:23:9:23:37 | SSA def(x) | Tuples.cs:23:9:23:37 | ... = ... |

csharp/ql/test/library-tests/dataflow/ssa/SsaRead.expected

@@ -65,7 +65,7 @@
 | Capture.cs:229:13:229:13 | i | Capture.cs:236:9:236:12 | SSA call def(i) | Capture.cs:237:34:237:34 | access to local variable i |
 | Consistency.cs:7:25:7:25 | b | Consistency.cs:7:25:7:25 | SSA param(b) | Consistency.cs:11:17:11:17 | access to parameter b |
 | Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
-| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
+| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | [finally: exception(Exception)] SSA def(i) | Consistency.cs:16:17:16:17 | access to local variable i |
 | Consistency.cs:25:29:25:29 | c | Consistency.cs:25:29:25:29 | SSA def(c) | Consistency.cs:26:13:26:13 | access to local variable c |
 | Consistency.cs:25:29:25:29 | c | Consistency.cs:25:29:25:29 | SSA def(c) | Consistency.cs:27:13:27:13 | access to local variable c |
 | Consistency.cs:26:13:26:19 | c.Field | Consistency.cs:25:29:25:29 | SSA qualifier def(c.Field) | Consistency.cs:26:13:26:19 | access to field Field |
@@ -356,7 +356,7 @@
 | Test.cs:46:16:46:18 | in | Test.cs:46:16:46:18 | SSA param(in) | Test.cs:48:13:48:15 | access to parameter in |
 | Test.cs:56:13:56:17 | this.field | Test.cs:46:10:46:10 | SSA entry def(this.field) | Test.cs:56:13:56:17 | access to field field |
 | Test.cs:56:13:56:17 | this.field | Test.cs:57:9:57:17 | SSA def(this.field) | Test.cs:58:13:58:17 | access to field field |
-| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | SSA def(e) | Test.cs:70:17:70:17 | access to local variable e |
+| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | [exception: DivideByZeroException] SSA def(e) | Test.cs:70:17:70:17 | access to local variable e |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:10:9:10:54 | SSA def(x) | Tuples.cs:11:13:11:13 | access to local variable x |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:14:9:14:32 | SSA def(x) | Tuples.cs:15:13:15:13 | access to local variable x |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:23:9:23:37 | SSA def(x) | Tuples.cs:24:13:24:13 | access to local variable x |

csharp/ql/test/library-tests/dataflow/ssa/SsaUltimateDef.expected

@@ -95,7 +95,7 @@
 | Capture.cs:229:13:229:13 | i | Capture.cs:236:9:236:12 | SSA call def(i) | Capture.cs:236:9:236:12 | SSA call def(i) |
 | Consistency.cs:7:25:7:25 | b | Consistency.cs:7:25:7:25 | SSA param(b) | Consistency.cs:7:25:7:25 | SSA param(b) |
 | Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:15:17:15:21 | SSA def(i) |
-| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | SSA def(i) | Consistency.cs:15:17:15:21 | SSA def(i) |
+| Consistency.cs:15:17:15:17 | i | Consistency.cs:15:17:15:21 | [finally: exception(Exception)] SSA def(i) | Consistency.cs:15:17:15:21 | [finally: exception(Exception)] SSA def(i) |
 | Consistency.cs:25:29:25:29 | c | Consistency.cs:25:29:25:29 | SSA def(c) | Consistency.cs:25:29:25:29 | SSA def(c) |
 | Consistency.cs:26:13:26:19 | c.Field | Consistency.cs:25:29:25:29 | SSA qualifier def(c.Field) | Consistency.cs:25:29:25:29 | SSA qualifier def(c.Field) |
 | Consistency.cs:30:30:30:30 | c | Consistency.cs:32:9:32:29 | SSA def(c) | Consistency.cs:32:9:32:29 | SSA def(c) |
@@ -455,7 +455,7 @@
 | Test.cs:46:29:46:32 | out | Test.cs:56:9:56:19 | SSA phi(out) | Test.cs:54:13:54:20 | SSA def(out) |
 | Test.cs:56:13:56:17 | this.field | Test.cs:46:10:46:10 | SSA entry def(this.field) | Test.cs:46:10:46:10 | SSA entry def(this.field) |
 | Test.cs:56:13:56:17 | this.field | Test.cs:57:9:57:17 | SSA def(this.field) | Test.cs:57:9:57:17 | SSA def(this.field) |
-| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | SSA def(e) | Test.cs:68:45:68:45 | SSA def(e) |
+| Test.cs:68:45:68:45 | e | Test.cs:68:45:68:45 | [exception: DivideByZeroException] SSA def(e) | Test.cs:68:45:68:45 | [exception: DivideByZeroException] SSA def(e) |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:10:9:10:54 | SSA def(x) | Tuples.cs:10:9:10:54 | SSA def(x) |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:14:9:14:32 | SSA def(x) | Tuples.cs:14:9:14:32 | SSA def(x) |
 | Tuples.cs:10:14:10:14 | x | Tuples.cs:23:9:23:37 | SSA def(x) | Tuples.cs:23:9:23:37 | SSA def(x) |