fu: static member init

Author: aschackmull

csharp/ql/lib/semmle/code/csharp/controlflow/ControlFlowGraph2.qll

@@ -85,7 +85,8 @@ module Ast implements AstSig<CS::Location> {
 
   Callable getEnclosingCallable(AstNode node) {
     result = node.(CS::ControlFlowElement).getEnclosingCallable() or
-    Initializers::obinitInitializes(result, getParent*(node))
+    result.(CS::ObjectInitMethod).initializes(getParent*(node)) or
+    Initializers::staticMemberInitializer(result, getParent*(node))
   }
 
   class Callable = CS::Callable;
@@ -94,7 +95,8 @@ module Ast implements AstSig<CS::Location> {
     result = c.getBody() or
     result = c.(CS::Constructor).getObjectInitializerCall() or
     result = c.(CS::Constructor).getInitializer() or
-    Initializers::obinitInitializes(c, result)
+    c.(CS::ObjectInitMethod).initializes(result) or
+    Initializers::staticMemberInitializer(c, result)
   }
 
   class Stmt = CS::Stmt;
@@ -248,44 +250,64 @@ private CompilationExt getCompilation(CS::File f) {
 }
 
 private module Initializers {
+  private import semmle.code.csharp.ExprOrStmtParent as ExprOrStmtParent
+
   /**
-   * A non-static member with an initializer, for example a field `int Field = 0`.
+   * The `expr_parent_top_level_adjusted()` relation restricted to exclude relations
+   * between properties and their getters' expression bodies in properties such as
+   * `int P => 0`.
+   *
+   * This is in order to only associate the expression body with one CFG scope, namely
+   * the getter (and not the declaration itself).
    */
-  class InitializedInstanceMember extends CS::Member {
-    private CS::AssignExpr ae;
-
-    InitializedInstanceMember() {
-      not this.isStatic() and
-      expr_parent_top_level(ae, _, this) and
-      not ae = any(CS::Callable c).getExpressionBody()
-    }
-
-    /** Gets the initializer expression. */
-    CS::AssignExpr getInitializer() { result = ae }
+  private predicate expr_parent_top_level_adjusted2(
+    CS::Expr child, int i, @top_level_exprorstmt_parent parent
+  ) {
+    ExprOrStmtParent::expr_parent_top_level_adjusted(child, i, parent) and
+    not exists(CS::Getter g |
+      g.getDeclaration() = parent and
+      i = 0
+    )
   }
 
   /**
-   * Holds if `obinit` is an object initializer method that performs the initialization
-   * of a member via assignment `init`.
+   * Holds if `init` is a static member initializer and `staticCtor` is the
+   * static constructor in the same declaring type. Hence, `staticCtor` can be
+   * considered to execute `init` prior to the execution of its body.
    */
-  predicate obinitInitializes(CS::ObjectInitMethod obinit, CS::AssignExpr init) {
-    exists(InitializedInstanceMember m |
-      obinit.getDeclaringType().getAMember() = m and
-      init = m.getInitializer()
+  predicate staticMemberInitializer(CS::Constructor staticCtor, CS::Expr init) {
+    exists(CS::Assignable a |
+      a.(CS::Modifiable).isStatic() and
+      expr_parent_top_level_adjusted2(init, _, a) and
+      a.getDeclaringType() = staticCtor.getDeclaringType() and
+      staticCtor.isStatic()
     )
   }
 
+  /**
+   * Gets the `i`th static member initializer expression for static constructor `staticCtor`.
+   */
+  CS::Expr initializedStaticMemberOrder(CS::Constructor staticCtor, int i) {
+    result =
+      rank[i + 1](CS::Expr init, CS::Location l |
+        staticMemberInitializer(staticCtor, init) and
+        l = init.getLocation()
+      |
+        init order by l.getStartLine(), l.getStartColumn(), l.getFile().getAbsolutePath()
+      )
+  }
+
   /**
    * Gets the `i`th member initializer expression for object initializer method `obinit`
    * in compilation `comp`.
    */
   CS::AssignExpr initializedInstanceMemberOrder(
     CS::ObjectInitMethod obinit, CompilationExt comp, int i
   ) {
-    obinitInitializes(obinit, result) and
+    obinit.initializes(result) and
     result =
       rank[i + 1](CS::AssignExpr ae0, CS::Location l |
-        obinitInitializes(obinit, ae0) and
+        obinit.initializes(ae0) and
         l = ae0.getLocation() and
         getCompilation(l.getFile()) = comp
       |
@@ -306,7 +328,6 @@ private module Initializers {
 }
 
 // module Consistency = ControlFlow::Consistency;
-
 private module Input implements InputSig1, InputSig2 {
   predicate cfgCachedStageRef() { CfgCachedStage::ref() }
 
@@ -407,12 +428,22 @@ private module Input implements InputSig1, InputSig2 {
   predicate step(PreControlFlowNode n1, PreControlFlowNode n2) {
     exists(CS::Constructor ctor |
       n1.(EntryNodeImpl).getEnclosingCallable() = ctor and
-      if exists(ctor.getObjectInitializerCall())
-      then n2.isBefore(ctor.getObjectInitializerCall())
+      if Initializers::staticMemberInitializer(ctor, _)
+      then n2.isBefore(Initializers::initializedStaticMemberOrder(ctor, 0))
       else
-        if exists(ctor.getInitializer())
-        then n2.isBefore(ctor.getInitializer())
-        else n2.isBefore(ctor.getBody())
+        if exists(ctor.getObjectInitializerCall())
+        then n2.isBefore(ctor.getObjectInitializerCall())
+        else
+          if exists(ctor.getInitializer())
+          then n2.isBefore(ctor.getInitializer())
+          else n2.isBefore(ctor.getBody())
+      or
+      exists(int i | n1.isAfter(Initializers::initializedStaticMemberOrder(ctor, i)) |
+        n2.isBefore(Initializers::initializedStaticMemberOrder(ctor, i + 1))
+        or
+        not exists(Initializers::initializedStaticMemberOrder(ctor, i + 1)) and
+        n2.isBefore(ctor.getBody())
+      )
       or
       exists(CompilationExt comp |
         n1.isAfter(getObjectInitializerCall(ctor, comp)) and