ssa.js - npm Package Compare versions

Comparing version 1.0.2 to 1.1.0

lib/ssa.js

@@ -42,2 +42,5 @@ 'use strict';
   this.search();
+
+  // Remove phis with no uses
+  this.reduce();
 };
@@ -146,3 +149,6 @@
     var undef = this.pipeline.create('ssa:undefined');
-    block.add(undef);
+    if (block.getLastControl() === null)
+      block.add(undef);
+    else
+      block.insert(block.nodes.length - 1, undef);
 
@@ -215,1 +221,49 @@ input = undef;
 };
+
+SSA.prototype.reduce = function reduce() {
+  for (var i = 0; i < this.pipeline.blocks.length; i++) {
+    var block = this.pipeline.blocks[i];
+    for (var j = block.nodes.length - 1; j >= 0; j--) {
+      var node = block.nodes[j];
+
+      // Phis are inserted at the block start
+      if (node.opcode !== 'ssa:phi')
+        break;
+
+      if (node.uses.length !== 0)
+        continue;
+
+      block.remove(j);
+      this.pipeline.remove(node);
+
+      // Remove `ssa:undefined` in predecessor blocks
+      this.reduceUndefined(block, node);
+    }
+  }
+};
+
+SSA.prototype.reduceUndefined = function reduceUndefined(block, phi) {
+  for (var i = 0; i < phi.inputs.length; i++) {
+    var input = phi.inputs[i];
+    if (input.opcode !== 'ssa:undefined')
+      continue;
+
+    // Somehow this `ssa:undefined` is used elsewhere
+    if (input.uses.length !== 0)
+      continue;
+
+    // Input should come from right branch
+    var pred = block.predecessors[i];
+
+    // `ssa:undefined` are inserted at the end of the block
+    for (var j = pred.nodes.length - 1; j >= 0; j--) {
+      var node = pred.nodes[j];
+      if (node !== input)
+        continue;
+
+      pred.remove(j);
+      this.pipeline.remove(node);
+      break;
+    }
+  }
+};

package.json

 {
   "name": "ssa.js",
-  "version": "1.0.2",
+  "version": "1.1.0",
   "description": "SSA Phi Insertion helper",
@@ -28,3 +28,3 @@ "main": "lib/ssa.js",
     "jshint": "^2.8.0",
-    "json-pipeline": "^1.4.1",
+    "json-pipeline": "^1.5.1",
     "mocha": "~1.17.0"
@@ -31,0 +31,0 @@ },

test/api-test.js

@@ -214,2 +214,89 @@ var fixtures = require('./fixtures');
   */});
+
+  test('reduce phi in loop', function() {/*
+    pipeline {
+      b0 {
+      }
+      b0 -> b1
+
+      b1 {
+      }
+      b1 -> b2, b3
+
+      b2 {
+        i0 = literal 1
+        i1 = ssa:store 0, i0
+        i2 = ssa:load 0
+      }
+      b2 -> b1
+
+      b3 {
+      }
+    }
+  */}, function() {/*
+    pipeline {
+      b0 {
+      }
+      b0 -> b1
+
+      b1 {
+      }
+      b1 -> b2, b3
+
+      b2 {
+        i0 = literal 1
+      }
+      b2 -> b1
+
+      b3 {
+      }
+    }
+  */});
+
+  test('insert `ssa:undefined` before control nodes', function() {/*
+    pipeline {
+      b0 {
+        i0 = if ^b0
+      }
+      b0 -> b1, b2
+
+      b1 {
+        i1 = jump ^b1
+      }
+      b1 -> b3
+
+      b2 {
+        i2 = literal 1
+        i3 = ssa:store 0, i2
+        i4 = jump ^b2
+      }
+      b2 -> b3
+
+      b3 {
+        i5 = ssa:load 0
+        i6 = return ^b3, i2
+      }
+    }
+  */}, function() {/*
+    pipeline {
+      b0 {
+        i0 = if ^b0
+      }
+      b0 -> b1, b2
+      b1 {
+        i3 = ssa:undefined
+        i1 = jump ^b1
+      }
+      b1 -> b3
+      b2 {
+        i2 = literal 1
+        i4 = jump ^b2
+      }
+      b2 -> b3
+      b3 {
+        i5 = ssa:phi i3, i2
+        i6 = return ^b3, i2
+      }
+    }
+  */});
 });

New alerts

Long strings

Supply chain risk

Contains long string literals, which may be a sign of obfuscated or packed code.

Found 1 instance in 1 package

Fixed alerts

Long strings

Supply chain risk

Contains long string literals, which may be a sign of obfuscated or packed code.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

22069

13.22%

Lines of code

495

31.65%

Worsened metrics

Number of low supply chain risk alerts

2

100%

No dependency changes