From f40d28f40288275415367023e0bf9f8c82c2916f Mon Sep 17 00:00:00 2001
From: Adrian Prantl <aprantl@apple.com>
Date: Thu, 19 Nov 2015 17:41:41 -0800
Subject: [PATCH] Debug Info: Don't reset the debug scope after leaving the
 outermost scope, because the debugger is not expecting the function epilogue
 to be in a different scope.

rdar://problem/23621232
---
 lib/IRGen/IRGenSIL.cpp      |  6 ++++--
 lib/SILGen/SILGenFunction.h |  6 +++---
 test/DebugInfo/return.swift | 13 ++++++++-----
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/lib/IRGen/IRGenSIL.cpp b/lib/IRGen/IRGenSIL.cpp
index 12db2a8d8ba00..abb358fdc884d 100644
--- a/lib/IRGen/IRGenSIL.cpp
+++ b/lib/IRGen/IRGenSIL.cpp
@@ -1568,6 +1568,7 @@ void IRGenSILFunction::visitSILBasicBlock(SILBasicBlock *BB) {
     if (IGM.DebugInfo) {
       // Set the debug info location for I, if applicable.
       SILLocation ILoc = I.getLoc();
+      auto DS = I.getDebugScope();
       // Handle cleanup locations.
       if (ILoc.getKind() == SILLocation::CleanupKind) {
         // Cleanup locations point to the decl of the the value that
@@ -1591,13 +1592,13 @@ void IRGenSILFunction::visitSILBasicBlock(SILBasicBlock *BB) {
         if (!KeepCurrentLocation) {
           assert(BB->getTerminator());
           ILoc = BB->getTerminator()->getLoc();
+          DS = BB->getTerminator()->getDebugScope();
         }
       } else if (InCleanupBlock) {
         KeepCurrentLocation = false;
         InCleanupBlock = false;
       }
 
-      auto DS = I.getDebugScope();
       assert((!DS || (DS->SILFn == CurSILFn || DS->InlinedCallSite)) &&
              "insn was not inlined, but belongs to a different function");
 
@@ -1612,7 +1613,8 @@ void IRGenSILFunction::visitSILBasicBlock(SILBasicBlock *BB) {
 
       // Ignore scope-less instructions and have IRBuilder reuse the
       // previous location and scope.
-      if (DS && !KeepCurrentLocation)
+      if (DS && !KeepCurrentLocation &&
+          !(ILoc.isInPrologue() && ILoc.getKind() == SILLocation::CleanupKind))
         IGM.DebugInfo->setCurrentLoc(Builder, DS, ILoc);
 
       // Function argument handling.
diff --git a/lib/SILGen/SILGenFunction.h b/lib/SILGen/SILGenFunction.h
index aa3e3eedd0541..fcf3b222c2c3a 100644
--- a/lib/SILGen/SILGenFunction.h
+++ b/lib/SILGen/SILGenFunction.h
@@ -502,9 +502,9 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
     DebugScopeStack.pop_back();
     if (DebugScopeStack.size())
       B.setCurrentDebugScope(DebugScopeStack.back());
-    else {
-      B.setCurrentDebugScope(F.getDebugScope());
-    }
+    // Don't reset the debug scope after leaving the outermost scope,
+    // because the debugger is not expecting the function epilogue to
+    // be in a different scope.
   }
 
   //===--------------------------------------------------------------------===//
diff --git a/test/DebugInfo/return.swift b/test/DebugInfo/return.swift
index 65107b9c1963c..d59aecbeb6bf7 100644
--- a/test/DebugInfo/return.swift
+++ b/test/DebugInfo/return.swift
@@ -9,7 +9,8 @@ class X {
 public func ifelseexpr() -> Int64 {
   var x = X(i:0); 
   // CHECK: [[META:%.*]] = call %swift.type* @_TMaC6return1X()
-  // CHECK: [[X:%.*]] = call %C6return1X* @_TFC6return1XCfT1iVs5Int64_S0_(i64 0, %swift.type* [[META]])
+  // CHECK: [[X:%.*]] = call %C6return1X* @_TFC6return1XCfT1iVs5Int64_S0_(
+  // CHECK-SAME:                                  i64 0, %swift.type* [[META]])
   // CHECK:  @swift_release to void (%C6return1X*)*)(%C6return1X* [[X]])
   if true {
     x.x++; 
@@ -17,9 +18,11 @@ public func ifelseexpr() -> Int64 {
     x.x--;
   }
   // CHECK:  @swift_release to void (%C6return1X*)*)(%C6return1X* [[X]])
-  // CHECK:  @swift_release to void (%C6return1X*)*)(%C6return1X* [[X]]) {{.*}}, !dbg ![[RELEASE:.*]]
-  // CHECK:  ret{{.*}}, !dbg ![[RET:.*]]
-  // CHECK: ![[RELEASE]] = !DILocation(line: [[@LINE+1]],
-  return x.x; // CHECK: ![[RET]] = !DILocation(line: [[@LINE]],
+  // CHECK:  @swift_release to void (%C6return1X*)*)(%C6return1X* [[X]])
+  // CHECK-SAME:                    , !dbg ![[RELEASE:.*]]
+
+  // The ret instruction should be in the same scope as the return expression.
+  // CHECK:  ret{{.*}}, !dbg ![[RELEASE]]
+  return x.x; // CHECK: ![[RELEASE]] = !DILocation(line: [[@LINE]], column: 3
 }