commit fa6b079b1231366696f6a497c6a084c73a35c85d
author Adrian Prantl <aprantl@apple.com> Thu May 02 17:30:20 2013 +0000
committer Adrian Prantl <aprantl@apple.com> Thu May 02 17:30:20 2013 +0000
tree 302668355094ed5d183c591e7fb9f529f451e715
parent d4147c4b2d4eba0327658f36c5a2c63f2d234991

Ensure that the line table for functions with cleanups is sequential.

If there is cleanup code, the cleanup code gets the debug location of
the closing '}'. The subsequent ret IR-instruction does not get a
debug location. The return _expression_ will get the debug location
of the return statement.

If the function contains only a single, simple return statement,
the cleanup code may become the first breakpoint in the function.
In this case we set the debug location for the cleanup code
to the location of the return statement.

rdar://problem/13442648

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180932 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CodeGenFunction.cpp

diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 0daae58..122e95b 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -44,6 +44,7 @@
     DebugInfo(0), DisableDebugInfo(false), CalleeWithThisReturn(0),
     DidCallStackSave(false),
     IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0),
+    NumStopPoints(0), NumSimpleReturnExprs(0),
     CXXABIThisDecl(0), CXXABIThisValue(0), CXXThisValue(0),
     CXXDefaultInitExprThis(0),
     CXXStructorImplicitParamDecl(0), CXXStructorImplicitParamValue(0),
@@ -187,16 +188,35 @@
   assert(BreakContinueStack.empty() &&
          "mismatched push/pop in break/continue stack!");
 
-  if (CGDebugInfo *DI = getDebugInfo())
-    DI->EmitLocation(Builder, EndLoc);
+  // If the function contains only a single, simple return statement,
+  // the cleanup code may become the first breakpoint in the
+  // function. To be safe set the debug location for it to the
+  // location of the return statement.  Otherwise point it to end of
+  // the function's lexical scope.
+  if (CGDebugInfo *DI = getDebugInfo()) {
+    if (NumSimpleReturnExprs == 1 && NumStopPoints == 1)
+      DI->EmitLocation(Builder, FirstStopPoint);
+    else
+      DI->EmitLocation(Builder, EndLoc);
+  }
 
   // Pop any cleanups that might have been associated with the
   // parameters.  Do this in whatever block we're currently in; it's
   // important to do this before we enter the return block or return
   // edges will be *really* confused.
-  if (EHStack.stable_begin() != PrologueCleanupDepth)
+  bool EmitRetDbgLoc = true;
+  if (EHStack.stable_begin() != PrologueCleanupDepth) {
     PopCleanupBlocks(PrologueCleanupDepth);
 
+    // Make sure the line table doesn't jump back into the body for
+    // the ret after it's been at EndLoc.
+    EmitRetDbgLoc = false;
+
+    if (CGDebugInfo *DI = getDebugInfo())
+      if (NumSimpleReturnExprs == 1 && NumStopPoints == 1)
+        DI->EmitLocation(Builder, EndLoc);
+  }
+
   // Emit function epilog (to return).
   EmitReturnBlock();
 
@@ -208,7 +228,7 @@
     DI->EmitFunctionEnd(Builder);
   }
 
-  EmitFunctionEpilog(*CurFnInfo);
+  EmitFunctionEpilog(*CurFnInfo, EmitRetDbgLoc);
   EmitEndEHSpec(CurCodeDecl);
 
   assert(EHStack.empty() &&