Make it illegal for two Functions to point to the same DISubprogram

As recently discussed on llvm-dev [1], this patch makes it illegal for
two Functions to point to the same DISubprogram and updates
FunctionCloner to also clone the debug info of a function to conform
to the new requirement. To simplify the implementation it also factors
out the creation of inlineAt locations from the Inliner into a
general-purpose utility in DILocation.

[1] http://lists.llvm.org/pipermail/llvm-dev/2017-May/112661.html
<rdar://problem/31926379>

Differential Revision: https://reviews.llvm.org/D32975

This reapplies r302469 with a fix for a bot failure (reparentDebugInfo
now checks for the case the orig and new function are identical).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302576 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 5 deletions

diff --git a/test/Verifier/metadata-function-dbg.ll b/test/Verifier/metadata-function-dbg.ll
index 24989ed7aa2e..6db40943ec38 100644
--- a/test/Verifier/metadata-function-dbg.ll
+++ b/test/Verifier/metadata-function-dbg.ll
@@ -3,12 +3,18 @@
 ; CHECK:      function declaration may not have a !dbg attachment
 declare !dbg !4 void @f1()
 
-define void @f2() !dbg !4 {
+; CHECK:      function must have a single !dbg attachment
+define void @f2() !dbg !4 !dbg !4 {
   unreachable
 }
 
-; CHECK:      function must have a single !dbg attachment
-define void @f3() !dbg !4 !dbg !4 {
+; CHECK:      DISubprogram attached to more than one function
+define void @f3() !dbg !4 {
+  unreachable
+}
+
+; CHECK:      DISubprogram attached to more than one function
+define void @f4() !dbg !4 {
   unreachable
 }
 
@@ -16,7 +22,7 @@ define void @f3() !dbg !4 !dbg !4 {
 ; CHECK:      function !dbg attachment must be a subprogram
 ; CHECK-NEXT: void ()* @bar
 ; CHECK-NEXT: !{{[0-9]+}} = !{}
-define void @bar() !dbg !6 {
+define void @bar() !dbg !3 {
   unreachable
 }
 
@@ -26,5 +32,5 @@ define void @bar() !dbg !6 {
 !llvm.dbg.cu = !{!1}
 !1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2)
 !2 = !DIFile(filename: "t.c", directory: "/path/to/dir")
+!3 = !{}
 !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !2, unit: !1)
-!6 = !{}