Check in getOrCreateSubprogramDIE if a declaration exists and if so o…

…utput

it first.

This is a more general fix to pr11300.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144324 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -934,6 +934,12 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
   if (SPDie)
     return SPDie;
 
+  DISubprogram SPDecl = SP.getFunctionDeclaration();
+  DIE *DeclDie = NULL;
+  if (SPDecl.isSubprogram()) {
+    DeclDie = getOrCreateSubprogramDIE(SPDecl);
+  }
+
   SPDie = new DIE(dwarf::DW_TAG_subprogram);
 
   // DW_TAG_inlined_subroutine may refer to this DIE.
@@ -952,8 +958,13 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
 
   // If this DIE is going to refer declaration info using AT_specification
   // then there is no need to add other attributes.
-  if (SP.getFunctionDeclaration().isSubprogram())
+  if (DeclDie) {
+    // Refer function declaration directly.
+    addDIEEntry(SPDie, dwarf::DW_AT_specification, dwarf::DW_FORM_ref4,
+                DeclDie);
+
     return SPDie;
+  }
 
   // Constructors and operators for anonymous aggregates do not have names.
   if (!SP.getName().empty())

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -598,20 +598,8 @@ void DwarfDebug::constructSubprogramDIE(CompileUnit *TheCU,
     // class type.
     return;
 
-  DISubprogram SPDecl = SP.getFunctionDeclaration();
-  DIE *DeclDie = NULL;
-  if (SPDecl.isSubprogram()) {
-    DeclDie = TheCU->getOrCreateSubprogramDIE(SPDecl);
-  }
-
   DIE *SubprogramDie = TheCU->getOrCreateSubprogramDIE(SP);
 
-  if (DeclDie) {
-    // Refer function declaration directly.
-    TheCU->addDIEEntry(SubprogramDie, dwarf::DW_AT_specification,
-                       dwarf::DW_FORM_ref4, DeclDie);
-  }
-
   // Add to map.
   TheCU->insertDIE(N, SubprogramDie);
 

test/DebugInfo/DW_AT_specification.ll

@@ -0,0 +1,43 @@
+; RUN: llc -mtriple=x86_64-apple-darwin %s -o %t -filetype=obj
+; RUN: llvm-dwarfdump %t | FileCheck %s
+
+; test that the DW_AT_specification is a back edge in the file.
+
+; CHECK: 0x0000003c: DW_TAG_subprogram [5] *
+; CHECK: 0x00000064: DW_AT_specification [DW_FORM_ref4]      (cu + 0x003c => {0x0000003c})
+
+
+@_ZZN3foo3barEvE1x = constant i32 0, align 4
+
+define void @_ZN3foo3barEv()  {
+entry:
+  ret void, !dbg !25
+}
+
+!llvm.dbg.cu = !{!0}
+
+!0 = metadata !{i32 720913, i32 0, i32 4, metadata !"<unknown>", metadata !"/Users/espindola/mozilla-central/obj-x86_64-apple-darwin11.2.0/toolkit/library", metadata !"clang version 3.0 ()", i1 true, i1 false, metadata !"", i32 0, metadata !1, metadata !1, metadata !3, metadata !18} ; [ DW_TAG_compile_unit ]
+!1 = metadata !{metadata !2}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4}
+!4 = metadata !{metadata !5}
+!5 = metadata !{i32 720942, i32 0, null, metadata !"bar", metadata !"bar", metadata !"_ZN3foo3barEv", metadata !6, i32 4, metadata !7, i1 false, i1 true, i32 0, i32 0, i32 0, i32 256, i1 false, void ()* @_ZN3foo3barEv, null, metadata !11, metadata !16} ; [ DW_TAG_subprogram ]
+!6 = metadata !{i32 720937, metadata !"nsNativeAppSupportBase.ii", metadata !"/Users/espindola/mozilla-central/obj-x86_64-apple-darwin11.2.0/toolkit/library", null} ; [ DW_TAG_file_type ]
+!7 = metadata !{i32 720917, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i32 0, i32 0, i32 0, metadata !8, i32 0, i32 0} ; [ DW_TAG_subroutine_type ]
+!8 = metadata !{null, metadata !9}
+!9 = metadata !{i32 720911, i32 0, metadata !"", i32 0, i32 0, i64 64, i64 64, i64 0, i32 64, metadata !10} ; [ DW_TAG_pointer_type ]
+!10 = metadata !{i32 720915, null, metadata !"foo", metadata !6, i32 1, i64 0, i64 0, i32 0, i32 4, i32 0, null, i32 0, i32 0} ; [ DW_TAG_structure_type ]
+!11 = metadata !{i32 720942, i32 0, metadata !12, metadata !"bar", metadata !"bar", metadata !"_ZN3foo3barEv", metadata !6, i32 2, metadata !7, i1 false, i1 false, i32 0, i32 0, null, i32 256, i1 false, null, null, i32 0, metadata !14} ; [ DW_TAG_subprogram ]
+!12 = metadata !{i32 720898, null, metadata !"foo", metadata !6, i32 1, i64 8, i64 8, i32 0, i32 0, null, metadata !13, i32 0, null, null} ; [ DW_TAG_class_type ]
+!13 = metadata !{metadata !11}
+!14 = metadata !{metadata !15}
+!15 = metadata !{i32 720932}                      ; [ DW_TAG_base_type ]
+!16 = metadata !{metadata !17}
+!17 = metadata !{i32 720932}                      ; [ DW_TAG_base_type ]
+!18 = metadata !{metadata !19}
+!19 = metadata !{metadata !20}
+!20 = metadata !{i32 720948, i32 0, metadata !5, metadata !"x", metadata !"x", metadata !"", metadata !6, i32 5, metadata !21, i32 1, i32 1, i32* @_ZZN3foo3barEvE1x} ; [ DW_TAG_variable ]
+!21 = metadata !{i32 720934, null, metadata !"", null, i32 0, i64 0, i64 0, i64 0, i32 0, metadata !22} ; [ DW_TAG_const_type ]
+!22 = metadata !{i32 720932, null, metadata !"int", null, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ]
+!25 = metadata !{i32 6, i32 1, metadata !26, null}
+!26 = metadata !{i32 720907, metadata !5, i32 4, i32 17, metadata !6, i32 0} ; [ DW_TAG_lexical_block ]