Ruby: Avoid computing Location::toString in full

Author: hvitved

ruby/ql/lib/codeql/Locations.qll

@@ -2,6 +2,15 @@
 
 import files.FileSystem
 
+bindingset[loc]
+pragma[inline_late]
+private string locationToString(Location loc) {
+  exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
+    loc.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
+    result = filepath + "@" + startline + ":" + startcolumn + ":" + endline + ":" + endcolumn
+  )
+}
+
 /**
  * A location as given by a file, a start line, a start column,
  * an end line, and an end column.
@@ -28,12 +37,8 @@ class Location extends @location {
   int getNumLines() { result = this.getEndLine() - this.getStartLine() + 1 }
 
   /** Gets a textual representation of this element. */
-  string toString() {
-    exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
-      this.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
-      result = filepath + "@" + startline + ":" + startcolumn + ":" + endline + ":" + endcolumn
-    )
-  }
+  pragma[inline]
+  string toString() { result = locationToString(this) }
 
   /**
    * Holds if this element is at the specified location.

ruby/ql/lib/codeql/ruby/frameworks/Rails.qll

@@ -303,6 +303,13 @@ private class CookiesSameSiteProtectionSetting extends Settings::NillableStringl
   }
 }
 
+pragma[nomagic]
+private predicate isPotentialRenderCall(MethodCall renderCall, Location loc, ErbFile erbFile) {
+  renderCall.getMethodName() = "render" and
+  loc = renderCall.getLocation() and
+  RenderCallUtils::getTemplateFile(renderCall) = erbFile
+}
+
 // TODO: initialization hooks, e.g. before_configuration, after_initialize...
 // TODO: initializers
 /** A synthetic global to represent the value passed to the `locals` argument of a render call for a specific ERB file. */
@@ -313,10 +320,11 @@ private class LocalAssignsHashSyntheticGlobal extends SummaryComponent::Syntheti
   private MethodCall renderCall;
 
   LocalAssignsHashSyntheticGlobal() {
-    this = "LocalAssignsHashSyntheticGlobal+" + id and
-    id = erbFile.getRelativePath() + "+" + renderCall.getLocation() and
-    renderCall.getMethodName() = "render" and
-    RenderCallUtils::getTemplateFile(renderCall) = erbFile
+    exists(Location loc |
+      this = "LocalAssignsHashSyntheticGlobal+" + id and
+      isPotentialRenderCall(renderCall, loc, erbFile) and
+      id = erbFile.getRelativePath() + "+" + loc
+    )
   }
 
   /** Gets the `ErbFile` which this locals hash is accessible from. */