C++: Improve performance of definitions.qll.

Author: criemen

cpp/ql/src/definitions.ql

@@ -9,5 +9,7 @@
 import definitions
 
 from Top e, Top def, string kind
-where def = definitionOf(e, kind, false)
+where
+  def = definitionOf(e, kind) and
+  not e.isFromTemplateInstantiation(_)
 select e, def, kind

cpp/ql/src/definitions.qll

@@ -77,9 +77,9 @@ predicate hasLocationInfo_Include(Include i, string path, int sl, int sc, int el
 
 /** Holds if `e` is a source or a target of jump-to-definition. */
 predicate interestingElement(Element e) {
-  exists(definitionOf(e, _, true))
+  exists(definitionOf(e, _))
   or
-  e = definitionOf(_, _, true)
+  e = definitionOf(_, _)
 }
 
 /**
@@ -124,10 +124,7 @@ private predicate constructorCallTypeMention(ConstructorCall cc, TypeMention tm)
 
 /**
  * Gets an element, of kind `kind`, that element `e` uses, if any.
- * If `includeTemplateInstantiations` is set, include information for
- * elements `e` that are inside of template instantiations.
- * Doing so yields multiple definitions for a single location, which can be
- * undesirably. For example, lgtm.com does not support that.
+ * Attention: This predicate yields multiple definitions for a single location.
  *
  * The `kind` is a string representing what kind of use it is:
  *  - `"M"` for function and method calls
@@ -137,7 +134,7 @@ private predicate constructorCallTypeMention(ConstructorCall cc, TypeMention tm)
  *  - `"I"` for import / include directives
  */
 cached
-Top definitionOf(Top e, string kind, boolean includeTemplateInstantiations) {
+Top definitionOf(Top e, string kind) {
   (
     // call -> function called
     kind = "M" and
@@ -200,13 +197,7 @@ Top definitionOf(Top e, string kind, boolean includeTemplateInstantiations) {
     not e.(Element).isInMacroExpansion() and
     // exclude nested macro invocations, as they will overlap with
     // the top macro invocation.
-    not exists(e.(MacroAccess).getParentInvocation()) and
-    (
-      includeTemplateInstantiations = true
-      or
-      includeTemplateInstantiations = false and
-      not e.isFromTemplateInstantiation(_)
-    )
+    not exists(e.(MacroAccess).getParentInvocation())
   ) and
   // Some entities have many locations. This can arise for an external
   // function that is frequently declared but not defined, or perhaps

cpp/ql/src/localDefinitions.ql

@@ -12,5 +12,5 @@ import definitions
 external string selectedSourceFile();
 
 from Top e, Top def, string kind
-where def = definitionOf(e, kind, true) and e.getFile() = getEncodedFile(selectedSourceFile())
-select e, def, kind
+where def = definitionOf(e, kind) and e.getFile() = getEncodedFile(selectedSourceFile())
+select e.getLocation(), def.getLocation(), kind

cpp/ql/src/localReferences.ql

@@ -12,5 +12,5 @@ import definitions
 external string selectedSourceFile();
 
 from Top e, Top def, string kind
-where def = definitionOf(e, kind, true) and def.getFile() = getEncodedFile(selectedSourceFile())
+where def = definitionOf(e, kind) and def.getFile() = getEncodedFile(selectedSourceFile())
 select e, def, kind

cpp/ql/test/query-tests/definitions/locationInfo.ql

@@ -4,7 +4,7 @@ import definitions
  * An element that is the source of a jump-to-definition link.
  */
 class Link extends Top {
-  Link() { exists(definitionOf(this, _, false)) }
+  Link() { exists(definitionOf(this, _)) }
 }
 
 /**
@@ -31,7 +31,7 @@ predicate linkLocationInfo(Link e, string filepath, int begin, int end) {
  * Gets a string describing a problem with a `Link`.
  */
 string issues(Link e) {
-  strictcount(Top def | def = definitionOf(e, _, false)) > 1 and
+  strictcount(Top def | def = definitionOf(e, _)) > 1 and
   result = "has more than one definition"
   or
   exists(string filepath1, int begin1, int end1, Link e2, string filepath2, int begin2, int end2 |
@@ -40,7 +40,9 @@ string issues(Link e) {
     filepath1 = filepath2 and
     not end1 < begin2 and
     not begin1 > end2 and
-    e != e2
+    e != e2 and
+    not e.isFromTemplateInstantiation(_) and
+    not e2.isFromTemplateInstantiation(_)
   ) and
   result = "overlaps another link"
 }