Fix task output pin connected to non-variables.

git-svn-id: file://localhost/svn/verilator/trunk/verilator@1016 77ca24e4-aefa-0310-84f0-b9a241c72d87

Changes

@@ -19,6 +19,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 **** Fix dropping of backslash quoted-quote at end of $display.
 
+**** Fix task output pin connected to non-variables. [Jonathan Kimmitt]
+
 **** Fix missing test_v in install datadir. [Holger Waechtler]
 
 * Verilator 3.660 2008/03/23

src/V3LinkLValue.cpp

@@ -166,10 +166,10 @@ private:
 
 public:
     // CONSTUCTORS
-    LinkLValueVisitor(AstNetlist* rootp) {
-	m_setRefLvalue = false;
+    LinkLValueVisitor(AstNode* nodep, bool start) {
+	m_setRefLvalue = start;
 	m_ftaskp = NULL;
-	rootp->accept(*this);
+	nodep->accept(*this);
     }
     virtual ~LinkLValueVisitor() {}
 };
@@ -179,5 +179,11 @@ public:
 
 void V3LinkLValue::linkLValue(AstNetlist* rootp) {
     UINFO(4,__FUNCTION__<<": "<<endl);
-    LinkLValueVisitor visitor(rootp);
+    LinkLValueVisitor visitor(rootp, false);
+}
+void V3LinkLValue::linkLValueSet(AstNode* nodep) {
+    // Called by later link functions when it is known a node needs
+    // to be converted to a lvalue.
+    UINFO(9,__FUNCTION__<<": "<<endl);
+    LinkLValueVisitor visitor(nodep, true);
 }

src/V3LinkLValue.h

@@ -31,6 +31,7 @@
 class V3LinkLValue {
 public:
     static void linkLValue(AstNetlist* nodep);
+    static void linkLValueSet(AstNode* nodep);
 };
 
 #endif // Guard

src/V3Task.cpp

@@ -41,6 +41,7 @@
 #include "V3Ast.h"
 #include "V3EmitCBase.h"
 #include "V3Graph.h"
+#include "V3LinkLValue.h"
 
 //######################################################################
 // Graph subclasses
@@ -360,11 +361,11 @@ private:
 			else if (portp->isOutput()) {
 			    // Make output variables
 			    // Correct lvalue; we didn't know when we linked
-			    if (AstVarRef* varrefp = pinp->castVarRef()) {
-				varrefp->lvalue(true);
-			    } else {
-				pinp->v3warn(TASKNSVAR,"Unsupported: Task output pin connected to non-variable");
-			    }
+			    // This is slightly scary; are we sure no decisions were made
+			    // before here based on this not being a lvalue?
+			    // Doesn't seem so; V3Unknown uses it earlier, but works ok.
+			    V3LinkLValue::linkLValueSet(pinp);
+
 			    // Even if it's referencing a varref, we still make a temporary
 			    // Else task(x,x,x) might produce incorrect results
 			    AstVarScope* outvscp = createVarScope (portp, namePrefix+"__"+portp->shortName());
@@ -445,11 +446,21 @@ private:
 			else if (portp->isOutput()) {
 			    // Make output variables
 			    // Correct lvalue; we didn't know when we linked
-			    if (AstVarRef* varrefp = pinp->castVarRef()) {
-				varrefp->lvalue(true);
-			    } else {
-				pinp->v3warn(TASKNSVAR,"Unsupported: Task output pin connected to non-variable");
-			    }
+			    // This is slightly scary; are we sure no decisions were made
+			    // before here based on this not being a lvalue?
+			    // Doesn't seem so; V3Unknown uses it earlier, but works ok.
+			    V3LinkLValue::linkLValueSet(pinp);
+
+			    // Even if it's referencing a varref, we still make a temporary
+			    // Else task(x,x,x) might produce incorrect results
+			    AstVarScope* outvscp = createVarScope (portp, namePrefix+"__"+portp->shortName());
+			    portp->user2p(outvscp);
+			    pinp->replaceWith(new AstVarRef(outvscp->fileline(), outvscp, true));
+			    AstAssign* assp = new AstAssign (pinp->fileline(),
+							     pinp,
+							     new AstVarRef(outvscp->fileline(), outvscp, false));
+			    // Put assignment BEHIND of all other statements
+			    beginp->addNext(assp);
 			}
 		    }
 		}

test_regress/t/t_func.v

@@ -7,6 +7,7 @@
 module t;
    reg [2:0] value;
    reg [31:0] global;
+   reg [31:0] vec [1:0];
 
    initial begin
       global = 1;
@@ -32,14 +33,22 @@ module t;
       nil_task(32'h012,32'h112,global);
       if (global !== 32'h124) $stop;
       
+      vec[0] = 32'h333;
+      vec[1] = 32'habc;
+      incr(vec[1],vec[0],vec[1]);
+      if (vec[0] != 32'h333) $stop;
+      if (vec[1] != 32'hdef) $stop;
+
+      incr(vec[2],vec[0],vec[2]);  // Reading/Writing past end of vector!
+
       $write("*-* All Finished *-*\n");
       $finish;
    end
 
    function [2:0] add;
-      input [2:0] from;
+      input [2:0] fromv;
       begin
-	 add = from + 3'd1;
+	 add = fromv + 3'd1;
 	 begin : named
 	    reg [31:0] flocal;
 	    flocal = 1;
@@ -49,13 +58,13 @@ module t;
    endfunction
 
    function [3:0] munge4;
-      input [3:0] from;		// Different from the 'from' signal above
+      input [3:0] fromv; // Different fromv than the 'fromv' signal above
       reg one;
       begin : named
 	 reg [1:0] flocal;
 	 // Function calling a function
 	 one = 1'b1;
-	 munge4 = {one, add(from[2:0])};
+	 munge4 = {one, add(fromv[2:0])};
       end
    endfunction
 

test_regress/t/t_func_bad.pl

@@ -14,7 +14,6 @@ compile (
 '%Error: t/t_func_bad.v:\d+: Too few arguments in function call
 %Error: t/t_func_bad.v:\d+: Too many arguments in function call
 %Error: t/t_func_bad.v:\d+: Too few arguments in function call
-%Error-TASKNSVAR: t/t_func_bad.v:\d+: Unsupported: Task output pin connected to non-variable
 %Error: t/t_func_bad.v:\d+: Outputs not allowed in function declarations
 %Error: Exiting due to',
 	 );