fix enable signal inferecne for smems' read ports (#289)

1 files changed, 138 insertions, 0 deletions

diff --git a/src/test/scala/firrtlTests/ChirrtlMemSpec.scala b/src/test/scala/firrtlTests/ChirrtlMemSpec.scala
new file mode 100644
index 00000000..e0691a6b
--- /dev/null
+++ b/src/test/scala/firrtlTests/ChirrtlMemSpec.scala
@@ -0,0 +1,138 @@
+/*
+Copyright (c) 2014 - 2016 The Regents of the University of
+California (Regents). All Rights Reserved.  Redistribution and use in
+source and binary forms, with or without modification, are permitted
+provided that the following conditions are met:
+   * Redistributions of source code must retain the above
+     copyright notice, this list of conditions and the following
+     two paragraphs of disclaimer.
+   * Redistributions in binary form must reproduce the above
+     copyright notice, this list of conditions and the following
+     two paragraphs of disclaimer in the documentation and/or other materials
+     provided with the distribution.
+   * Neither the name of the Regents nor the names of its contributors
+     may be used to endorse or promote products derived from this
+     software without specific prior written permission.
+IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
+SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,
+ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
+REGENTS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF
+ANY, PROVIDED HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION
+TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
+MODIFICATIONS.
+*/
+
+package firrtlTests
+
+import firrtl._
+import firrtl.ir._
+import firrtl.passes._
+import firrtl.Mappers._
+import Annotations._
+
+class ChirrtlMemSpec extends LowTransformSpec {
+  object MemEnableCheckPass extends Pass {
+    val name = "Check Enable Signal for Chirrtl Mems"
+    type Netlist = collection.mutable.HashMap[String, Expression]
+    def buildNetlist(netlist: Netlist)(s: Statement): Statement = {
+      s match {
+        case s: Connect => Utils.kind(s.loc) match {
+          case MemKind => netlist(s.loc.serialize) = s.expr
+          case _ =>
+        }
+        case _ =>
+      }
+      s map buildNetlist(netlist)
+    }
+
+    // walks on memories and checks whether or not read enables are high
+    def checkStmt(netlist: Netlist)(s: Statement): Boolean = s match {
+      case s: DefMemory if s.name == "mem" && s.readers.size == 1=>
+        val en = MemPortUtils.memPortField(s, s.readers.head, "en")
+        // memory read enable ?= 1
+        WrappedExpression.weq(netlist(en.serialize), Utils.one)
+      case s: Block =>
+        s.stmts exists checkStmt(netlist)
+      case _ => false
+    }
+
+    def run (c: Circuit) = {
+      val errors = new Errors
+      val check = c.modules exists {
+        case m: Module =>
+          val netlist = new Netlist
+          checkStmt(netlist)(buildNetlist(netlist)(m.body))
+        case m: ExtModule => false
+      }
+      if (!check) {
+        errors append new PassException(
+          "Enable signal for the read port is incorrect!")
+        errors.trigger
+      }
+      c
+    }
+  }
+
+  object MemEnableCheck extends Transform with SimpleRun {
+    def execute(c: Circuit, map: AnnotationMap) =
+      run(c, Seq(ConstProp, MemEnableCheckPass))
+  }
+
+  def transform = MemEnableCheck
+
+  "Sequential Memory" should "have correct enable signals" in {
+    val input = """
+circuit foo :
+  module foo :
+    input clk : Clock
+    input reset : UInt<1>
+    output io : {flip wen : UInt<1>, flip in : UInt<1>, flip counter : UInt<2>, out : UInt<1>}
+
+    io is invalid
+    smem mem : UInt<1>[4]
+    node T_0 = add(io.counter, UInt<1>("h01"))
+    node temp = tail(T_0, 1)
+    read mport bar = mem[temp], clk
+    when io.wen :
+      write mport T_1 = mem[io.counter], clk
+      T_1 <= io.in
+    io.out <= bar
+""".stripMargin
+
+    val annotationMap = AnnotationMap(Nil)
+    val writer = new java.io.StringWriter
+    compile(parse(input), annotationMap, writer)
+    // Check correctness of firrtl
+    parse(writer.toString)
+  }
+
+  "Combinational Memory" should "have correct enable signals" in {
+    val input = """
+circuit foo :
+  module foo :
+    input clk : Clock
+    input reset : UInt<1>
+    output io : {flip ren: UInt<1>, flip wen : UInt<1>, flip in : UInt<1>, flip counter : UInt<2>, out : UInt<1>}
+
+    io is invalid
+    cmem mem : UInt<1>[4]
+    reg counter : UInt<1>, clk with : (reset => (reset, UInt<1>("h0")))
+    read mport bar = mem[counter], clk
+    when io.ren:
+      counter <= add(counter, UInt<1>("h1"))
+    when io.wen :
+      write mport T_1 = mem[io.counter], clk
+      T_1 <= io.in
+    io.out <= bar
+""".stripMargin
+
+    val annotationMap = AnnotationMap(Nil)
+    val writer = new java.io.StringWriter
+    compile(parse(input), annotationMap, writer)
+    // Check correctness of firrtl
+    parse(writer.toString)
+  }
+}