[Dwarf] avoid emitting multiple AT_const_value for static memebers.

Testing case is reduced from MultiSource/BenchMarks/Prolangs-C++/deriv1.

rdar://problem/13071590


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174235 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 72 insertions, 3 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index f0655e6..dad1054 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1286,6 +1286,7 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
   // If this is a static data member definition, some attributes belong
   // to the declaration DIE.
   DIE *VariableDIE = NULL;
+  bool IsStaticMember = false;
   DIDerivedType SDMDecl = GV.getStaticDataMemberDeclaration();
   if (SDMDecl.Verify()) {
     assert(SDMDecl.isStaticMember() && "Expected static member decl");
@@ -1295,6 +1296,7 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
     getOrCreateContextDIE(SDMDecl.getContext());
     VariableDIE = getDIE(SDMDecl);
     assert(VariableDIE && "Static member decl has no context?");
+    IsStaticMember = true;
   }
 
   // If this is not a static data member definition, create the variable
@@ -1348,9 +1350,13 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
       addString(VariableDIE, dwarf::DW_AT_MIPS_linkage_name,
                 getRealLinkageName(LinkageName));
   } else if (const ConstantInt *CI =
-             dyn_cast_or_null<ConstantInt>(GV.getConstant()))
-    addConstantValue(VariableDIE, CI, GTy.isUnsignedDIType());
-  else if (const ConstantExpr *CE = getMergedGlobalExpr(N->getOperand(11))) {
+             dyn_cast_or_null<ConstantInt>(GV.getConstant())) {
+    // AT_const_value was added when the static memeber was created. To avoid
+    // emitting AT_const_value multiple times, we only add AT_const_value when
+    // it is not a static member.
+    if (!IsStaticMember)
+      addConstantValue(VariableDIE, CI, GTy.isUnsignedDIType());
+  } else if (const ConstantExpr *CE = getMergedGlobalExpr(N->getOperand(11))) {
     addToAccelTable = true;
     // GV is a merged global.
     DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
diff --git a/test/DebugInfo/X86/multiple-at-const-val.ll b/test/DebugInfo/X86/multiple-at-const-val.ll
new file mode 100644
index 0000000..03afc0f
--- /dev/null
+++ b/test/DebugInfo/X86/multiple-at-const-val.ll
@@ -0,0 +1,63 @@
+; RUN: llc -O0 %s -mtriple=x86_64-apple-darwin -filetype=obj -o %t
+; RUN: llvm-dwarfdump %t | FileCheck %s
+
+; rdar://13071590
+; Check we are not emitting mutliple AT_const_value for a single member.
+; CHECK: .debug_info contents:
+; CHECK: DW_TAG_compile_unit
+; CHECK: DW_TAG_class_type
+; CHECK: DW_TAG_member
+; CHECK: badbit
+; CHECK: DW_AT_const_value [DW_FORM_data4]	(0x00000001)
+; CHECK-NOT: DW_AT_const_value
+; CHECK: NULL
+
+%"class.std::basic_ostream" = type { i32 (...)**, %"class.std::basic_os" }
+%"class.std::basic_os" = type { %"class.std::os_base", %"class.std::basic_ostream"*, i8, i8 }
+%"class.std::os_base" = type { i32 (...)**, i64, i64, i32, i32, i32 }
+
+@_ZSt4cout = external global %"class.std::basic_ostream"
+@.str = private unnamed_addr constant [6 x i8] c"c is \00", align 1
+
+define i32 @main() ssp uwtable {
+entry:
+  %call1.i = tail call %"class.std::basic_ostream"* @test(%"class.std::basic_ostream"* @_ZSt4cout, i8* getelementptr inbounds ([6 x i8]* @.str, i64 0, i64 0), i64 5)
+  ret i32 0
+}
+
+declare %"class.std::basic_ostream"* @test(%"class.std::basic_ostream"*, i8*, i64)
+
+declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone
+
+!llvm.dbg.cu = !{!0}
+
+!0 = metadata !{i32 786449, i32 0, i32 4, metadata !"student2.cpp", metadata !"/privite/tmp", metadata !"clang version 3.3 (trunk 174207)", i1 true, i1 true, metadata !"", i32 0, metadata !1, metadata !955, metadata !956, metadata !1786} ; [ DW_TAG_compile_unit ] [/privite/tmp/student2.cpp] [DW_LANG_C_plus_plus]
+!1 = metadata !{metadata !2}
+!2 = metadata !{metadata !26}
+!4 = metadata !{i32 786489, null, metadata !"std", metadata !5, i32 48} ; [ DW_TAG_namespace ]
+!5 = metadata !{i32 786473, metadata !"os_base.h", metadata !"/privite/tmp", null} ; [ DW_TAG_file_type ]
+!25 = metadata !{i32 786472, metadata !"_S_os_fmtflags_end", i64 65536} ; [ DW_TAG_enumerator ]
+!26 = metadata !{i32 786436, metadata !4, metadata !"_Ios_Iostate", metadata !5, i32 146, i64 32, i64 32, i32 0, i32 0, null, metadata !27, i32 0, i32 0} ; [ DW_TAG_enumeration_type ]
+!27 = metadata !{metadata !28, metadata !29, metadata !30, metadata !31, metadata !32}
+!28 = metadata !{i32 786472, metadata !"_S_goodbit", i64 0} ; [ DW_TAG_enumerator ] [_S_goodbit :: 0]
+!29 = metadata !{i32 786472, metadata !"_S_badbit", i64 1} ; [ DW_TAG_enumerator ] [_S_badbit :: 1]
+!30 = metadata !{i32 786472, metadata !"_S_eofbit", i64 2} ; [ DW_TAG_enumerator ] [_S_eofbit :: 2]
+!31 = metadata !{i32 786472, metadata !"_S_failbit", i64 4} ; [ DW_TAG_enumerator ] [_S_failbit :: 4]
+!32 = metadata !{i32 786472, metadata !"_S_os_ostate_end", i64 65536} ; [ DW_TAG_enumerator ] [_S_os_ostate_end :: 65536]
+!49 = metadata !{i32 786434, metadata !4, metadata !"os_base", metadata !5, i32 200, i64 1728, i64 64, i32 0, i32 0, null, metadata !50, i32 0, metadata !49, null} ; [ DW_TAG_class_type ]
+!50 = metadata !{metadata !77}
+!54 = metadata !{i32 786453, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !55, i32 0, i32 0} ; [ DW_TAG_subroutine_type ]
+!55 = metadata !{metadata !56}
+!56 = metadata !{i32 786468, null, metadata !"int", null, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ]
+!77 = metadata !{i32 786445, metadata !49, metadata !"badbit", metadata !5, i32 331, i64 0, i64 0, i64 0, i32 4096, metadata !78, i32 1} ; [ DW_TAG_member ]
+!78 = metadata !{i32 786470, null, metadata !"", null, i32 0, i64 0, i64 0, i64 0, i32 0, metadata !79} ; [ DW_TAG_const_type ]
+!79 = metadata !{i32 786454, metadata !49, metadata !"ostate", metadata !5, i32 327, i64 0, i64 0, i64 0, i32 0, metadata !26} ; [ DW_TAG_typedef ]
+!468 = metadata !{i32 0}
+!955 = metadata !{metadata !468}
+!956 = metadata !{metadata !957}
+!957 = metadata !{metadata !960}
+!960 = metadata !{i32 786478, i32 0, metadata !961, metadata !"main", metadata !"main", metadata !"", metadata !961, i32 73, metadata !54, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, i32 ()* @main, null, null, metadata !955, i32 73} ; [ DW_TAG_subprogram ]
+!961 = metadata !{i32 786473, metadata !"student2.cpp", metadata !"/privite/tmp", null} ; [ DW_TAG_file_type ]
+!1786 = metadata !{metadata !1787}
+!1787 = metadata !{metadata !1800}
+!1800 = metadata !{i32 786484, i32 0, metadata !5, metadata !"badbit", metadata !"badbit", metadata !"badbit", metadata !5, i32 331, metadata !78, i32 1, i32 1, i32 1, metadata !77} ; [ DW_TAG_variable ]