Debugging infomration is encoded in llvm IR using metadata. This is designed

such a way that debug info for symbols preserved even if symbols are
optimized away by the optimizer. 

Add new special pass to remove debug info for such symbols.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107416 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 47 insertions, 0 deletions

diff --git a/test/Transforms/StripSymbols/2010-07-01-DeadDbgInfo.ll b/test/Transforms/StripSymbols/2010-07-01-DeadDbgInfo.ll
new file mode 100644
index 0000000000..721f0c8f70
--- /dev/null
+++ b/test/Transforms/StripSymbols/2010-07-01-DeadDbgInfo.ll
@@ -0,0 +1,47 @@
+; RUN: opt -strip-dead-debug-info | llvm-dis -o %t.ll
+; RUN: grep -v bar %t.ll
+; RUN: grep -v abcd %t.ll
+
+@xyz = global i32 2                               ; <i32*> [#uses=1]
+
+declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone
+
+define i32 @fn() nounwind readnone ssp {
+entry:
+  ret i32 0, !dbg !17
+}
+
+define i32 @foo(i32 %i) nounwind readonly ssp {
+entry:
+  tail call void @llvm.dbg.value(metadata !{i32 %i}, i64 0, metadata !14), !dbg !19
+  %.0 = load i32* @xyz, align 4                   ; <i32> [#uses=1]
+  ret i32 %.0, !dbg !20
+}
+
+!llvm.dbg.sp = !{!0, !5, !9}
+!llvm.dbg.lv.bar = !{!12}
+!llvm.dbg.lv.foo = !{!14}
+!llvm.dbg.gv = !{!15, !16}
+
+!0 = metadata !{i32 524334, i32 0, metadata !1, metadata !"bar", metadata !"bar", metadata !"", metadata !1, i32 5, metadata !3, i1 true, i1 true, i32 0, i32 0, null, i1 false, i1 true, null} ; [ DW_TAG_subprogram ]
+!1 = metadata !{i32 524329, metadata !"g.c", metadata !"/tmp/", metadata !2} ; [ DW_TAG_file_type ]
+!2 = metadata !{i32 524305, i32 0, i32 1, metadata !"g.c", metadata !"/tmp/", metadata !"4.2.1 (Based on Apple Inc. build 5658) (LLVM build)", i1 true, i1 true, metadata !"", i32 0} ; [ DW_TAG_compile_unit ]
+!3 = metadata !{i32 524309, metadata !1, metadata !"", metadata !1, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !4, i32 0, null} ; [ DW_TAG_subroutine_type ]
+!4 = metadata !{null}
+!5 = metadata !{i32 524334, i32 0, metadata !1, metadata !"fn", metadata !"fn", metadata !"fn", metadata !1, i32 6, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i1 false, i1 true, i32 ()* @fn} ; [ DW_TAG_subprogram ]
+!6 = metadata !{i32 524309, metadata !1, metadata !"", metadata !1, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null} ; [ DW_TAG_subroutine_type ]
+!7 = metadata !{metadata !8}
+!8 = metadata !{i32 524324, metadata !1, metadata !"int", metadata !1, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ]
+!9 = metadata !{i32 524334, i32 0, metadata !1, metadata !"foo", metadata !"foo", metadata !"foo", metadata !1, i32 7, metadata !10, i1 false, i1 true, i32 0, i32 0, null, i1 false, i1 true, i32 (i32)* @foo} ; [ DW_TAG_subprogram ]
+!10 = metadata !{i32 524309, metadata !1, metadata !"", metadata !1, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !11, i32 0, null} ; [ DW_TAG_subroutine_type ]
+!11 = metadata !{metadata !8, metadata !8}
+!12 = metadata !{i32 524544, metadata !13, metadata !"bb", metadata !1, i32 5, metadata !8} ; [ DW_TAG_auto_variable ]
+!13 = metadata !{i32 524299, metadata !0, i32 5, i32 0} ; [ DW_TAG_lexical_block ]
+!14 = metadata !{i32 524545, metadata !9, metadata !"i", metadata !1, i32 7, metadata !8} ; [ DW_TAG_arg_variable ]
+!15 = metadata !{i32 524340, i32 0, metadata !1, metadata !"abcd", metadata !"abcd", metadata !"", metadata !1, i32 2, metadata !8, i1 true, i1 true, null} ; [ DW_TAG_variable ]
+!16 = metadata !{i32 524340, i32 0, metadata !1, metadata !"xyz", metadata !"xyz", metadata !"", metadata !1, i32 3, metadata !8, i1 false, i1 true, i32* @xyz} ; [ DW_TAG_variable ]
+!17 = metadata !{i32 6, i32 0, metadata !18, null}
+!18 = metadata !{i32 524299, metadata !5, i32 6, i32 0} ; [ DW_TAG_lexical_block ]
+!19 = metadata !{i32 7, i32 0, metadata !9, null}
+!20 = metadata !{i32 10, i32 0, metadata !21, null}
+!21 = metadata !{i32 524299, metadata !9, i32 7, i32 0} ; [ DW_TAG_lexical_block ]