Ruby: fix some flow summary join orders

The flow summaries that are implemented with an abstract base class
restricting the method name, and child classes using that method name,
had unfortunate join orders:

r1 = JOIN Call::MethodCall::getMethodName#dispred#f0820431#ff WITH Call::MethodCall::getMethodName#dispred#f0820431#ff ON FIRST 1 OUTPUT Lhs.0, (Lhs.1 ++ "_arg"), Rhs.1

Author: nickrolfe

ruby/ql/lib/codeql/ruby/frameworks/core/Array.qll

@@ -192,12 +192,17 @@ module Array {
     }
   }
 
+  private class ElementReferenceReadMethodName extends string {
+    ElementReferenceReadMethodName() { this = ["[]", "slice"] }
+  }
+
   /** A call to `[]`, or its alias, `slice`. */
   abstract private class ElementReferenceReadSummary extends SummarizedCallable {
     MethodCall mc;
+    ElementReferenceReadMethodName methodName;
 
     bindingset[this]
-    ElementReferenceReadSummary() { mc.getMethodName() = ["[]", "slice"] }
+    ElementReferenceReadSummary() { mc.getMethodName() = methodName }
 
     override MethodCall getACall() { result = mc }
   }
@@ -207,7 +212,7 @@ module Array {
     private ConstantValue cv;
 
     ElementReferenceReadKnownSummary() {
-      this = mc.getMethodName() + "(" + cv.serialize() + ")" and
+      this = methodName + "(" + cv.serialize() + ")" and
       mc.getNumberOfArguments() = 1 and
       cv = getKnownElementIndex(mc.getArgument(0))
     }
@@ -225,7 +230,7 @@ module Array {
    */
   private class ElementReferenceReadUnknownSummary extends ElementReferenceReadSummary {
     ElementReferenceReadUnknownSummary() {
-      this = mc.getMethodName() + "(index)" and
+      this = methodName + "(index)" and
       mc.getNumberOfArguments() = 1 and
       isUnknownElementIndex(mc.getArgument(0))
     }
@@ -267,7 +272,7 @@ module Array {
           or
           rl.isExclusive() and end = e - 1
         ) and
-        this = "[](" + start + ".." + end + ")"
+        this = methodName + "(" + start + ".." + end + ")"
       )
     }
 
@@ -291,7 +296,7 @@ module Array {
    */
   private class ElementReferenceRangeReadUnknownSummary extends ElementReferenceReadSummary {
     ElementReferenceRangeReadUnknownSummary() {
-      this = "[](range_unknown)" and
+      this = methodName + "(range_unknown)" and
       (
         mc.getNumberOfArguments() = 2 and
         (
@@ -2007,17 +2012,22 @@ module Enumerable {
     }
   }
 
+  private class GrepMethodName extends string {
+    GrepMethodName() { this = ["grep", "grep_v"] }
+  }
+
   abstract private class GrepSummary extends SummarizedCallable {
     MethodCall mc;
+    GrepMethodName methodName;
 
     bindingset[this]
-    GrepSummary() { mc.getMethodName() = ["grep", "grep_v"] }
+    GrepSummary() { mc.getMethodName() = methodName }
 
     override MethodCall getACall() { result = mc }
   }
 
   private class GrepBlockSummary extends GrepSummary {
-    GrepBlockSummary() { this = mc.getMethodName() + "(block)" and exists(mc.getBlock()) }
+    GrepBlockSummary() { this = methodName + "(block)" and exists(mc.getBlock()) }
 
     override predicate propagatesFlowExt(string input, string output, boolean preservesValue) {
       (
@@ -2032,7 +2042,7 @@ module Enumerable {
   }
 
   private class GrepNoBlockSummary extends GrepSummary {
-    GrepNoBlockSummary() { this = mc.getMethodName() + "(no_block)" and not exists(mc.getBlock()) }
+    GrepNoBlockSummary() { this = methodName + "(no_block)" and not exists(mc.getBlock()) }
 
     override predicate propagatesFlowExt(string input, string output, boolean preservesValue) {
       input = "Argument[self].Element[any]" and
@@ -2052,18 +2062,23 @@ module Enumerable {
     }
   }
 
+  private class InjectMethodName extends string {
+    // `reduce` is an alias for `inject`.
+    InjectMethodName() { this = ["inject", "reduce"] }
+  }
+
   abstract private class InjectSummary extends SummarizedCallable {
     MethodCall mc;
+    InjectMethodName methodName; // adding this as a field helps give a better join order
 
-    // `reduce` is an alias for `inject`.
     bindingset[this]
-    InjectSummary() { mc.getMethodName() = ["inject", "reduce"] }
+    InjectSummary() { mc.getMethodName() = methodName }
 
     override MethodCall getACall() { result = mc }
   }
 
   private class InjectNoArgSummary extends InjectSummary {
-    InjectNoArgSummary() { this = mc.getMethodName() + "_no_arg" and mc.getNumberOfArguments() = 0 }
+    InjectNoArgSummary() { this = methodName + "_no_arg" and mc.getNumberOfArguments() = 0 }
 
     override predicate propagatesFlowExt(string input, string output, boolean preservesValue) {
       // The no-argument variant of inject passes element 0 to the first block
@@ -2083,7 +2098,7 @@ module Enumerable {
   }
 
   private class InjectArgSummary extends InjectSummary {
-    InjectArgSummary() { this = mc.getMethodName() + "_arg" and mc.getNumberOfArguments() > 0 }
+    InjectArgSummary() { this = methodName + "_arg" and mc.getNumberOfArguments() > 0 }
 
     override predicate propagatesFlowExt(string input, string output, boolean preservesValue) {
       (
@@ -2101,18 +2116,23 @@ module Enumerable {
     }
   }
 
+  private class MinOrMaxByMethodName extends string {
+    MinOrMaxByMethodName() { this = ["min_by", "max_by"] }
+  }
+
   abstract private class MinOrMaxBySummary extends SummarizedCallable {
     MethodCall mc;
+    MinOrMaxByMethodName methodName; // adding this as a field helps give a better join order
 
     bindingset[this]
-    MinOrMaxBySummary() { mc.getMethodName() = ["min_by", "max_by"] }
+    MinOrMaxBySummary() { mc.getMethodName() = methodName }
 
     override MethodCall getACall() { result = mc }
   }
 
   private class MinOrMaxByNoArgSummary extends MinOrMaxBySummary {
     MinOrMaxByNoArgSummary() {
-      this = mc.getMethodName() + "_no_arg" and
+      this = methodName + "_no_arg" and
       mc.getNumberOfArguments() = 0
     }
 
@@ -2125,7 +2145,7 @@ module Enumerable {
 
   private class MinOrMaxByArgSummary extends MinOrMaxBySummary {
     MinOrMaxByArgSummary() {
-      this = mc.getMethodName() + "_arg" and
+      this = methodName + "_arg" and
       mc.getNumberOfArguments() > 0
     }
 
@@ -2136,18 +2156,23 @@ module Enumerable {
     }
   }
 
+  private class MinOrMaxMethodName extends string {
+    MinOrMaxMethodName() { this = ["min", "max"] }
+  }
+
   abstract private class MinOrMaxSummary extends SummarizedCallable {
     MethodCall mc;
+    MinOrMaxMethodName methodName;
 
     bindingset[this]
-    MinOrMaxSummary() { mc.getMethodName() = ["min", "max"] }
+    MinOrMaxSummary() { mc.getMethodName() = methodName }
 
     override MethodCall getACall() { result = mc }
   }
 
   private class MinOrMaxNoArgNoBlockSummary extends MinOrMaxSummary {
     MinOrMaxNoArgNoBlockSummary() {
-      this = mc.getMethodName() + "_no_arg_no_block" and
+      this = methodName + "_no_arg_no_block" and
       mc.getNumberOfArguments() = 0 and
       not exists(mc.getBlock())
     }
@@ -2161,7 +2186,7 @@ module Enumerable {
 
   private class MinOrMaxArgNoBlockSummary extends MinOrMaxSummary {
     MinOrMaxArgNoBlockSummary() {
-      this = mc.getMethodName() + "_arg_no_block" and
+      this = methodName + "_arg_no_block" and
       mc.getNumberOfArguments() > 0 and
       not exists(mc.getBlock())
     }
@@ -2175,7 +2200,7 @@ module Enumerable {
 
   private class MinOrMaxNoArgBlockSummary extends MinOrMaxSummary {
     MinOrMaxNoArgBlockSummary() {
-      this = mc.getMethodName() + "_no_arg_block" and
+      this = methodName + "_no_arg_block" and
       mc.getNumberOfArguments() = 0 and
       exists(mc.getBlock())
     }
@@ -2189,7 +2214,7 @@ module Enumerable {
 
   private class MinOrMaxArgBlockSummary extends MinOrMaxSummary {
     MinOrMaxArgBlockSummary() {
-      this = mc.getMethodName() + "_arg_block" and
+      this = methodName + "_arg_block" and
       mc.getNumberOfArguments() > 0 and
       exists(mc.getBlock())
     }