Merge pull request #248 from microsoft/fix-ps-performance

PS: Fix lots of performance problems

Author: LWSimpkins

powershell/ql/lib/semmle/code/powershell/ast/internal/Ast.qll

@@ -3,6 +3,7 @@ private import AstImport
 class Ast extends TAst {
   string toString() { none() }
 
+  pragma[nomagic]
   final Ast getParent() { result.getChild(_) = this }
 
   Location getLocation() {

powershell/ql/lib/semmle/code/powershell/ast/internal/CallExpr.qll

@@ -26,10 +26,16 @@ class CallExpr extends Expr, TCallExpr {
    */
   Expr getCallee() { none() }
 
-  /** Holds if an argument with name `name` is provided to this call. */
+  /**
+   * Holds if an argument with name `name` is provided to this call.
+   * Note: `name` is normalized to lower case.
+   */
   final predicate hasNamedArgument(string name) { exists(this.getNamedArgument(name)) }
 
-  /** Gets the argument to this call with the name `name`. */
+  /**
+   * Gets the named argument with the given name.
+   * Note: `name` is normalized to lower case.
+   */
   Expr getNamedArgument(string name) { none() }
 
   /** Gets any argument to this call. */

powershell/ql/lib/semmle/code/powershell/ast/internal/Command.qll

@@ -1,7 +1,9 @@
 private import AstImport
 
 class CmdCall extends CallExpr, TCmd {
-  final override string getLowerCaseName() { result = getRawAst(this).(Raw::Cmd).getLowerCaseName() }
+  final override string getLowerCaseName() {
+    result = getRawAst(this).(Raw::Cmd).getLowerCaseName()
+  }
 
   final override Expr getArgument(int i) { synthChild(getRawAst(this), cmdArgument(i), result) }
 

powershell/ql/lib/semmle/code/powershell/ast/internal/Parameter.qll

@@ -65,6 +65,8 @@ class PipelineByPropertyNameParameter extends Parameter instanceof PipelineByPro
    * Gets the iterator variable that is used to iterate over the elements in the pipeline.
    */
   PipelineByPropertyNameIteratorVariable getIteratorVariable() { result.getParameter() = this }
+
+  ProcessBlock getProcessBlock() { result = this.getIteratorVariable().getProcessBlock() }
 }
 
 /**

powershell/ql/lib/semmle/code/powershell/ast/internal/Raw/Ast.qll

@@ -5,10 +5,12 @@ private import Scope
 class Ast extends @ast {
   final string toString() { none() }
 
+  pragma[nomagic]
   final Ast getParent() { result.getAChild() = this }
 
   Ast getChild(ChildIndex i) { none() }
 
+  pragma[nomagic]
   final Ast getAChild() { result = this.getChild(_) }
 
   Location getLocation() { none() }

powershell/ql/lib/semmle/code/powershell/ast/internal/Synthesis.qll

@@ -26,7 +26,8 @@ newtype VarKind =
   PipelineIteratorKind() or
   PipelineByPropertyNameIteratorKind(string name) {
     exists(Raw::ProcessBlock pb |
-      name = pb.getScriptBlock().getParamBlock().getAPipelineByPropertyNameParameter().getLowerCaseName()
+      name =
+        pb.getScriptBlock().getParamBlock().getAPipelineByPropertyNameParameter().getLowerCaseName()
     )
   }
 
@@ -771,28 +772,35 @@ private module IteratorAccessSynth {
     // TODO: We could join on something other than the string if we wanted (i.e., the raw parameter).
     v.getPropertyName().toLowerCase() = result and
     result =
-      pb.getScriptBlock()
-          .getParamBlock()
-          .getAPipelineByPropertyNameParameter()
-          .getLowerCaseName()
+      pb.getScriptBlock().getParamBlock().getAPipelineByPropertyNameParameter().getLowerCaseName()
   }
 
+  private Raw::Ast getParent(Raw::Ast a) { a.getParent() = result }
+
+  private predicate isVarAccess(Raw::VarAccess va) { any() }
+
+  private predicate isProcessBlock(Raw::ProcessBlock pb) { any() }
+
+  private Raw::ProcessBlock getProcessBlock(Raw::VarAccess va) =
+    doublyBoundedFastTC(getParent/1, isVarAccess/1, isProcessBlock/1)(va, result)
+
   private class IteratorAccessSynth extends Synthesis {
     final override predicate isRelevant(Raw::Ast a) {
-      exists(Raw::ProcessBlock pb, Raw::VarAccess va |
-        va = a and
-        pb = va.getParent+()
-      |
+      exists(Raw::VarAccess va | va = a |
         va.getUserPath() = "_"
         or
-        va.getUserPath().toLowerCase() =
-          pb.getScriptBlock().getParamBlock().getPipelineParameter().getLowerCaseName()
-        or
-        va.getUserPath().toLowerCase() =
-          pb.getScriptBlock()
-              .getParamBlock()
-              .getAPipelineByPropertyNameParameter()
-              .getLowerCaseName()
+        exists(Raw::ProcessBlock pb |
+          pragma[only_bind_into](pb) = getProcessBlock(pragma[only_bind_into](va))
+        |
+          va.getUserPath().toLowerCase() =
+            pb.getScriptBlock().getParamBlock().getPipelineParameter().getLowerCaseName()
+          or
+          va.getUserPath().toLowerCase() =
+            pb.getScriptBlock()
+                .getParamBlock()
+                .getAPipelineByPropertyNameParameter()
+                .getLowerCaseName()
+        )
       )
     }
 
@@ -810,7 +818,7 @@ private module IteratorAccessSynth {
 
     private PipelineOrPipelineByPropertyNameIteratorVariable varAccess(Raw::VarAccess va) {
       exists(Raw::ProcessBlock pb |
-        pb = va.getParent+() and
+        pb = getProcessBlock(va) and
         result = TVariableSynth(pb, _) and
         va.getUserPath().toLowerCase() = getAPipelineIteratorName(pb, result)
       )
@@ -896,6 +904,7 @@ private module PipelineAccess {
         exists(PipelineByPropertyNameParameter pipelineVar, Raw::PipelineByPropertyNameParameter p |
           i = processBlockPipelineByPropertyNameVarReadAccess(p.getLowerCaseName()) and
           getResultAst(p) = pipelineVar and
+          pipelineVar = TVariableSynth(pb.getScriptBlock(), _) and
           child = SynthChild(VarAccessSynthKind(pipelineVar))
         )
       )

powershell/ql/lib/semmle/code/powershell/ast/internal/Variable.qll

@@ -59,8 +59,9 @@ module Private {
 
     PipelineParameterImpl() {
       exists(int index |
-        i = FunParam(index) and
-        any(Synthesis s).pipelineParameterHasIndex(super.getDeclaringScopeImpl(), index)
+        i = FunParam(pragma[only_bind_into](index)) and
+        any(Synthesis s)
+            .pipelineParameterHasIndex(super.getDeclaringScopeImpl(), pragma[only_bind_into](index))
       )
     }
 

powershell/ql/lib/semmle/code/powershell/controlflow/internal/ControlFlowGraphImpl.qll

@@ -427,15 +427,17 @@ module Trees {
     override predicate last(AstNode last, Completion c) {
       // Exit the loop body when the condition is false
       last(this.getCondition(), last, c) and
-      this.entersLoopWhenConditionIs(c.(BooleanCompletion).getValue().booleanNot())
+      this.entersLoopWhenConditionIs(pragma[only_bind_into](c.(BooleanCompletion)
+            .getValue()
+            .booleanNot()))
       or
       super.last(last, c)
     }
 
     override predicate succ(AstNode pred, AstNode succ, Completion c) {
       // Condition -> body
       last(this.getCondition(), pred, c) and
-      this.entersLoopWhenConditionIs(c.(BooleanCompletion).getValue()) and
+      this.entersLoopWhenConditionIs(pragma[only_bind_into](c.(BooleanCompletion).getValue())) and
       first(this.getBody(), succ)
       or
       // Body -> condition

powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPrivate.qll

@@ -465,27 +465,47 @@ class NamedSet extends NamedSet0 {
   /** Gets the non-empty set of names, if any. */
   NamedSetModule::Set asNonEmpty() { this = TNonEmptyNamedSet(result) }
 
+  /** Gets the `i`'th name in this set according to some ordering. */
+  private string getRankedName(int i) {
+    result = rank[i + 1](string s | s = this.getALowerCaseName() | s)
+  }
+
   /** Holds if this is the empty set. */
   predicate isEmpty() { this = TEmptyNamedSet() }
 
-  /** Gets a name in this set. */
-  string getAName() { this.asNonEmpty().contains(result) }
+  int getSize() {
+    result = strictcount(this.getALowerCaseName())
+    or
+    this.isEmpty() and
+    result = 0
+  }
+
+  /** Gets a lower-case name in this set. */
+  string getALowerCaseName() { this.asNonEmpty().contains(result) }
 
   /** Gets the textual representation of this set. */
   string toString() {
-    result = "{" + strictconcat(this.getAName(), ", ") + "}"
+    result = "{" + strictconcat(this.getALowerCaseName(), ", ") + "}"
     or
     this.isEmpty() and
     result = "{}"
   }
 
+  private CfgNodes::ExprNodes::CallExprCfgNode getABindingCallRec(int i) {
+    exists(string name | name = this.getRankedName(i) and exists(result.getNamedArgument(name)) |
+      i = 0
+      or
+      result = this.getABindingCallRec(i - 1)
+    )
+  }
+
   /**
    * Gets a `CfgNodes::CallCfgNode` that provides a named parameter for every name in `this`.
    *
    * NOTE: The `CfgNodes::CallCfgNode` may also provide more names.
    */
   CfgNodes::ExprNodes::CallExprCfgNode getABindingCall() {
-    forex(string name | name = this.getAName() | exists(result.getNamedArgument(name)))
+    result = this.getABindingCallRec(this.getSize() - 1)
     or
     this.isEmpty() and
     exists(result)
@@ -496,16 +516,28 @@ class NamedSet extends NamedSet0 {
    * this set.
    */
   CfgNodes::ExprNodes::CallExprCfgNode getAnExactBindingCall() {
-    forex(string name | name = this.getAName() | exists(result.getNamedArgument(name))) and
-    forex(string name | exists(result.getNamedArgument(name)) | name = this.getAName())
+    result = this.getABindingCallRec(this.getSize() - 1) and
+    strictcount(string name | result.hasNamedArgument(name)) = this.getSize()
     or
     this.isEmpty() and
     not exists(result.getNamedArgument(_))
   }
 
+  pragma[nomagic]
+  private Function getAFunctionRec(int i) {
+    i = 0 and
+    result.getAParameter().getLowerCaseName() = this.getRankedName(0)
+    or
+    exists(string name |
+      pragma[only_bind_into](name) = this.getRankedName(i) and
+      result.getAParameter().getLowerCaseName() = pragma[only_bind_into](name) and
+      result = this.getAFunctionRec(i - 1)
+    )
+  }
+
   /** Gets a function that has a parameter for each name in this set. */
   Function getAFunction() {
-    forex(string name | name = this.getAName() | result.getAParameter().matchesName(name))
+    result = this.getAFunctionRec(this.getSize() - 1)
     or
     this.isEmpty() and
     exists(result)
@@ -533,6 +565,12 @@ private module ParameterNodes {
     }
   }
 
+  bindingset[p]
+  pragma[inline_late]
+  private predicate namedSetHasParameter(NamedSet ns, Parameter p) {
+    ns.getALowerCaseName() = p.getLowerCaseName()
+  }
+
   /**
    * The value of a normal parameter at function entry, viewed as a node in a data
    * flow graph.
@@ -566,13 +604,13 @@ private module ParameterNodes {
           f = parameter.getFunction() and
           f = ns.getAFunction() and
           name = parameter.getLowerCaseName() and
-          not name = ns.getAName() and
+          not name = ns.getALowerCaseName() and
           j =
             i -
               count(int k, Parameter p |
                 k < i and
                 p = getNormalParameter(f, k) and
-                p.getLowerCaseName() = ns.getAName()
+                namedSetHasParameter(ns, p)
               )
         )
       )

powershell/ql/lib/semmle/code/powershell/dataflow/internal/SsaImpl.qll

@@ -278,7 +278,7 @@ private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInpu
      * guard to `branch`.
      */
     predicate controlsBranchEdge(SsaInput::BasicBlock bb1, SsaInput::BasicBlock bb2, boolean branch) {
-      hasBranchEdge(bb1, bb2, branch)
+      this.hasBranchEdge(bb1, bb2, branch)
     }
     /**
      * Holds if the evaluation of this guard to `branch` corresponds to the edge