Merge pull request #1291 from freechipsproject/infer-resets-last-connect-semantics

Infer resets last connect semantics

1 files changed, 78 insertions, 19 deletions

diff --git a/src/test/scala/firrtlTests/InferResetsSpec.scala b/src/test/scala/firrtlTests/InferResetsSpec.scala
index ac13033a..501dce20 100644
--- a/src/test/scala/firrtlTests/InferResetsSpec.scala
+++ b/src/test/scala/firrtlTests/InferResetsSpec.scala
@@ -4,7 +4,7 @@ package firrtlTests
 
 import firrtl._
 import firrtl.ir._
-import firrtl.passes.{CheckHighForm, CheckTypes}
+import firrtl.passes.{CheckHighForm, CheckTypes, CheckInitialization}
 import firrtl.transforms.InferResets
 import FirrtlCheckers._
 
@@ -37,7 +37,6 @@ class InferResetsSpec extends FirrtlFlatSpec {
       |    y <= asFixedPoint(r, 0)
       |    z <= asAsyncReset(r)""".stripMargin
     )
-    println(result.getEmittedCircuit)
     result should containLine ("wire r : UInt<1>")
     result should containLine ("r <= a")
     result should containLine ("v <= asUInt(r)")
@@ -125,44 +124,68 @@ class InferResetsSpec extends FirrtlFlatSpec {
     result should containTree { case Port(_, "buzz_bar_1_b", Input, AsyncResetType) => true }
   }
 
-  it should "NOT allow last connect semantics to pick the right type for Reset" in {
-    an [InferResets.DifferingDriverTypesException] shouldBe thrownBy {
+  it should "not crash if a ResetType has no drivers" in {
+    a [CheckInitialization.RefNotInitializedException] shouldBe thrownBy {
+      compile(s"""
+        |circuit test :
+        |  module test :
+        |    output out : Reset
+        |    wire w : Reset
+        |    out <= w
+        |    out <= UInt(1)
+        |""".stripMargin
+      )
+    }
+  }
+
+  it should "allow last connect semantics to pick the right type for Reset" in {
+    val result =
       compile(s"""
         |circuit top :
         |  module top :
         |    input reset0 : AsyncReset
         |    input reset1 : UInt<1>
         |    output out : Reset
+        |    wire w0 : Reset
         |    wire w1 : Reset
-        |    wire w2 : Reset
-        |    w1 <= reset0
-        |    w2 <= reset1
+        |    w0 <= reset0
+        |    w1 <= reset1
+        |    out <= w0
         |    out <= w1
-        |    out <= w2
         |""".stripMargin
       )
-    }
+    result should containTree { case DefWire(_, "w0", AsyncResetType) => true }
+    result should containTree { case DefWire(_, "w1", BoolType)       => true }
+    result should containTree { case Port(_, "out", Output, BoolType) => true }
   }
 
-  it should "NOT support last connect semantics across whens" in {
-    an [InferResets.DifferingDriverTypesException] shouldBe thrownBy {
+  it should "support last connect semantics across whens" in {
+    val result =
       compile(s"""
         |circuit top :
         |  module top :
         |    input reset0 : AsyncReset
-        |    input reset1 : UInt<1>
-        |    input en0 : UInt<1>
+        |    input reset1 : AsyncReset
+        |    input reset2 : UInt<1>
+        |    input en : UInt<1>
         |    output out : Reset
+        |    wire w0 : Reset
         |    wire w1 : Reset
         |    wire w2 : Reset
-        |    w1 <= reset0
-        |    w2 <= reset1
-        |    out <= w1
-        |    when en0 :
-        |      out <= w2
+        |    w0 <= reset0
+        |    w1 <= reset1
+        |    w2 <= reset2
+        |    out <= w2
+        |    when en :
+        |      out <= w0
+        |    else :
+        |      out <= w1
         |""".stripMargin
       )
-    }
+    result should containTree { case DefWire(_, "w0", AsyncResetType) => true }
+    result should containTree { case DefWire(_, "w1", AsyncResetType) => true }
+    result should containTree { case DefWire(_, "w2", BoolType)       => true }
+    result should containTree { case Port(_, "out", Output, AsyncResetType) => true }
   }
 
   it should "not allow different Reset Types to drive a single Reset" in {
@@ -186,6 +209,42 @@ class InferResetsSpec extends FirrtlFlatSpec {
     }
   }
 
+  it should "allow concrete reset types to overrule invalidation" in {
+    val result = compile(s"""
+      |circuit test :
+      |  module test :
+      |    input in : AsyncReset
+      |    output out : Reset
+      |    out is invalid
+      |    out <= in
+      |""".stripMargin)
+    result should containTree { case Port(_, "out", Output, AsyncResetType) => true }
+  }
+
+  it should "default to BoolType for Resets that are only invalidated" in {
+    val result = compile(s"""
+      |circuit test :
+      |  module test :
+      |    output out : Reset
+      |    out is invalid
+      |""".stripMargin)
+    result should containTree { case Port(_, "out", Output, BoolType) => true }
+  }
+
+  it should "not error if component of ResetType is invalidated and connected to an AsyncResetType" in {
+    val result = compile(s"""
+      |circuit test :
+      |  module test :
+      |    input cond : UInt<1>
+      |    input in : AsyncReset
+      |    output out : Reset
+      |    out is invalid
+      |    when cond :
+      |      out <= in
+      |""".stripMargin)
+    result should containTree { case Port(_, "out", Output, AsyncResetType) => true }
+  }
+
   it should "allow ResetType to drive AsyncResets or UInt<1>" in {
     val result1 = compile(s"""
       |circuit top :