Use ExprContext.None for fake stack slots used to disable stack sched…

…uler optimizations. Fixes dotnet#7148.
AlekseyTs · Dec 1, 2015 · a85bef7 · a85bef7
1 parent 41950e2
commit a85bef7
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Showing 3 changed files with 51 additions and 4 deletions.
diff --git a/src/Compilers/CSharp/Portable/CodeGen/Optimizer.cs b/src/Compilers/CSharp/Portable/CodeGen/Optimizer.cs
@@ -331,6 +331,7 @@ private bool Includes(int val)
     //      Foo(x, ref x)     <-- x cannot be a stack local as it is used in different contexts.
     internal enum ExprContext
     {
+        None,
         Sideeffects,
         Value,
         Address,
@@ -494,6 +495,7 @@ protected override BoundExpression VisitExpressionWithoutStackGuard(BoundExpress
 
         private void PushEvalStack(BoundExpression result, ExprContext context)
         {
+            Debug.Assert(result != null || context == ExprContext.None);
             _evalStack.Add(ValueTuple.Create(result, context));
         }
 
@@ -879,7 +881,7 @@ public override BoundNode VisitAssignmentOperator(BoundAssignmentOperator node)
             if (mayPushReceiver)
             {
                 // push unknown value just to prevent access to stack locals.
-                PushEvalStack(null, ExprContext.Address);
+                PushEvalStack(null, ExprContext.None);
             }
 
             right = VisitExpression(node.Right, rhsContext);
@@ -1326,7 +1328,7 @@ public override BoundNode VisitComplexConditionalReceiver(BoundComplexConditiona
 
             var origStack = StackDepth();
 
-            PushEvalStack(null, ExprContext.Value);
+            PushEvalStack(null, ExprContext.None);
 
             var cookie = GetStackStateCookie(); // implicit goto here 
 
@@ -1446,7 +1448,7 @@ public override BoundNode VisitCatchBlock(BoundCatchBlock node)
             if (exceptionSourceOpt != null)
             {
                 // runtime pushes the exception object
-                PushEvalStack(null, ExprContext.Value);
+                PushEvalStack(null, ExprContext.None);
                 _counter++;
 
                 // We consume it by writing into the exception source.

diff --git a/src/Compilers/VisualBasic/Portable/CodeGen/Optimizer/StackScheduler.Analyzer.vb b/src/Compilers/VisualBasic/Portable/CodeGen/Optimizer/StackScheduler.Analyzer.vb
@@ -144,6 +144,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.CodeGen
             End Function
 
             Private Sub PushEvalStack(result As BoundExpression, context As ExprContext)
+                Debug.Assert(result IsNot Nothing OrElse context = ExprContext.None)
                 _evalStack.Add(ValueTuple.Create(result, context))
             End Sub
 
@@ -586,7 +587,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.CodeGen
 
                 If mayPushReceiver Then
                     'push unknown value just to prevent access to stack locals.
-                    PushEvalStack(Nothing, ExprContext.Address)
+                    PushEvalStack(Nothing, ExprContext.None)
                 End If
 
                 right = VisitExpression(node.Right, rhsContext)

diff --git a/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTests.vb b/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTests.vb
@@ -13470,6 +13470,50 @@ End Module
   IL_002d:  call       "Sub System.Console.WriteLine(Integer)"
   IL_0032:  ret
 }
+]]>)
+        End Sub
+
+        <Fact, WorkItem(7148, "https://github.com/dotnet/roslyn/issues/7148")>
+        Public Sub Issue7148()
+            Dim c = CompileAndVerify(
+<compilation>
+    <file name="a.vb">
+Public Class TestClass
+    Private _rotation As Decimal
+    Private Sub CalculateDimensions()
+        _rotation *= 180 / System.Math.PI 'This line causes '"vbc.exe" exited with code -2146232797'
+    End Sub
+
+    Shared Sub Main()
+        Dim x as New TestClass()
+        x._rotation = 1
+        x.CalculateDimensions()
+        System.Console.WriteLine(x._rotation)
+    End Sub    
+End Class
+    </file>
+</compilation>, options:=TestOptions.ReleaseExe,
+                expectedOutput:="57.2957795130823")
+
+            c.VerifyIL("TestClass.CalculateDimensions",
+            <![CDATA[
+{
+  // Code size       40 (0x28)
+  .maxstack  3
+  .locals init (Decimal& V_0)
+  IL_0000:  ldarg.0
+  IL_0001:  ldflda     "TestClass._rotation As Decimal"
+  IL_0006:  dup
+  IL_0007:  stloc.0
+  IL_0008:  ldloc.0
+  IL_0009:  ldobj      "Decimal"
+  IL_000e:  call       "Function System.Convert.ToDouble(Decimal) As Double"
+  IL_0013:  ldc.r8     57.2957795130823
+  IL_001c:  mul
+  IL_001d:  newobj     "Sub Decimal..ctor(Double)"
+  IL_0022:  stobj      "Decimal"
+  IL_0027:  ret
+}
 ]]>)
         End Sub