Merge pull request #1545 from Microsoft/forki-i1536

This takes Steffens repro and has a slightly different fix -- Fixes I1556

Author: KevinRansom

src/absil/ilwritepdb.fs

@@ -493,7 +493,7 @@ let writePdbInfo fixupOverlappingSequencePoints showTimes f fpdb info cvChunk =
                   match Map.tryFind k res with
                     | Some xsR -> xsR := sp :: !xsR; res
                     | None     -> Map.add k (ref [sp]) res
-               
+
                 let res = Array.fold add res sps
                 let res = Map.toList res  // ordering may not be stable 
                 List.map (fun (_,x) -> Array.ofList !x) res
@@ -502,22 +502,27 @@ let writePdbInfo fixupOverlappingSequencePoints showTimes f fpdb info cvChunk =
                   if spset.Length > 0 then 
                     Array.sortInPlaceWith SequencePoint.orderByOffset spset
                     let sps = 
-                      spset |> Array.map (fun sp -> 
-                           // Ildiag.dprintf "token 0x%08lx has an sp at offset 0x%08x\n" minfo.MethToken sp.Offset 
-                           (sp.Offset, sp.Line, sp.Column,sp.EndLine, sp.EndColumn)) 
-                  // Use of alloca in implementation of pdbDefineSequencePoints can give stack overflow here 
+                        spset |> Array.map (fun sp -> 
+                            // Ildiag.dprintf "token 0x%08lx has an sp at offset 0x%08x\n" minfo.MethToken sp.Offset 
+                            (sp.Offset, sp.Line, sp.Column,sp.EndLine, sp.EndColumn))
+                    // Use of alloca in implementation of pdbDefineSequencePoints can give stack overflow here 
                     if sps.Length < 5000 then 
-                      pdbDefineSequencePoints !pdbw (getDocument spset.[0].Document) sps)
+                        pdbDefineSequencePoints !pdbw (getDocument spset.[0].Document) sps)
 
               // Write the scopes 
-              let rec writePdbScope top sco = 
-                  if top || sco.Locals.Length <> 0 || sco.Children.Length <> 0 then 
-                      pdbOpenScope !pdbw sco.StartOffset
+              let rec writePdbScope parent sco = 
+                  if parent = None || sco.Locals.Length <> 0 || sco.Children.Length <> 0 then
+                      // Only nest scopes if the child scope is a different size from 
+                      let nested =
+                          match parent with
+                          | Some p -> sco.StartOffset <> p.StartOffset || sco.EndOffset <> p.EndOffset
+                          | None -> true
+                      if nested then pdbOpenScope !pdbw sco.StartOffset
                       sco.Locals |> Array.iter (fun v -> pdbDefineLocalVariable !pdbw v.Name v.Signature v.Index)
-                      sco.Children |> Array.iter (writePdbScope false)
-                      pdbCloseScope !pdbw sco.EndOffset
-              writePdbScope true minfo.RootScope 
+                      sco.Children |> Array.iter (writePdbScope (if nested then Some sco else parent))
+                      if nested then pdbCloseScope !pdbw sco.EndOffset
 
+              writePdbScope None minfo.RootScope 
               pdbCloseMethod !pdbw
           end)
     reportTime showTimes "PDB: Wrote methods"

tests/fsharpqa/Source/CodeGen/EmittedIL/SerializableAttribute/ToplevelModule.il.bsl

@@ -1720,21 +1720,19 @@
   {
     // Code size       14 (0xe)
     .maxstack  3
-    .locals init ([0] string V_0,
-             [1] string greeting)
-    .line 12,12 : 9,31
+    .locals init ([0] string greeting,
+             [1] string V_1)
+    .line 12,12 : 9,31 ''
     IL_0000:  nop
     IL_0001:  call       string ABC::get_greeting()
     IL_0006:  stloc.0
-    .line 22,22 : 13,35
+    .line 22,22 : 13,35 ''
     IL_0007:  call       string ABC/ABC::get_greeting()
     IL_000c:  stloc.1
     IL_000d:  ret
   } // end of method $ABC::.cctor
-
 } // end of class '<StartupCode$TopLevelModule>'.$ABC
 
-
 // =============================================================
 
 // *********** DISASSEMBLY COMPLETE ***********************

tests/fsharpqa/Source/CodeGen/EmittedIL/SerializableAttribute/ToplevelModuleP.il.bsl

@@ -1692,18 +1692,17 @@
   {
     // Code size       14 (0xe)
     .maxstack  3
-    .locals init ([0] string V_0,
-             [1] string greeting)
-    .line 12,12 : 9,31
+    .locals init ([0] string greeting,
+             [1] string V_1)
+    .line 12,12 : 9,31 ''
     IL_0000:  nop
     IL_0001:  call       string ABC::get_greeting()
     IL_0006:  stloc.0
-    .line 22,22 : 13,35
+    .line 22,22 : 13,35 ''
     IL_0007:  call       string ABC/ABC::get_greeting()
     IL_000c:  stloc.1
     IL_000d:  ret
   } // end of method $ABC::.cctor
-
 } // end of class '<StartupCode$ToplevelModuleP>'.$ABC
 
 

tests/fsharpqa/Source/CodeGen/EmittedIL/SerializableAttribute/ToplevelNamespace.il.bsl

@@ -2513,18 +2513,17 @@
   {
     // Code size       14 (0xe)
     .maxstack  3
-    .locals init ([0] string V_0,
-             [1] string greeting)
-    .line 19,19 : 9,31
+    .locals init ([0] string greeting,
+             [1] string V_1)
+    .line 19,19 : 9,31 ''
     IL_0000:  nop
     IL_0001:  call       string XYZ.ABC::get_greeting()
     IL_0006:  stloc.0
-    .line 29,29 : 13,35
+    .line 29,29 : 13,35 ''
     IL_0007:  call       string XYZ.ABC/ABC::get_greeting()
     IL_000c:  stloc.1
     IL_000d:  ret
   } // end of method $ToplevelNamespace::.cctor
-
 } // end of class '<StartupCode$ToplevelNamespace>'.$ToplevelNamespace
 
 

tests/fsharpqa/Source/CodeGen/EmittedIL/SerializableAttribute/ToplevelNamespaceP.il.bsl

@@ -2471,18 +2471,17 @@
   {
     // Code size       14 (0xe)
     .maxstack  3
-    .locals init ([0] string V_0,
-             [1] string greeting)
-    .line 19,19 : 9,31
+    .locals init ([0] string greeting,
+             [1] string V_1)
+    .line 19,19 : 9,31 ''
     IL_0000:  nop
     IL_0001:  call       string XYZ.ABC::get_greeting()
     IL_0006:  stloc.0
-    .line 29,29 : 13,35
+    .line 29,29 : 13,35 ''
     IL_0007:  call       string XYZ.ABC/ABC::get_greeting()
     IL_000c:  stloc.1
     IL_000d:  ret
   } // end of method $ToplevelNamespace::.cctor
-
 } // end of class '<StartupCode$ToplevelNamespaceP>'.$ToplevelNamespace