From 19a8b90763995b18552ea9841e3b2be9bf3a96ac Mon Sep 17 00:00:00 2001 From: David Blaikie Date: Wed, 4 Jun 2014 01:30:59 +0000 Subject: [PATCH] DebugInfo: Partial revert r209984 due to more cases where abstract DbgVariables do not have associated DIEs. Along with a test case to demonstrate that due to inlining order there are cases where abstract variable DIEs are not constructed since the abstract subprogram was built due to a previous inlining that optimized away those variables. This produces incorrect debug info (the 'missing' abstract variable causes the inlined instance of that variable to be emitted with a full description (name, line, file) rather than referencing the abstract origin), but this commit at least ensures that it doesn't crash... llvm-svn: 210143 --- llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp | 6 +- llvm/test/DebugInfo/missing-abstract-variable.ll | 181 +++++++++++++++++++++++ 2 files changed, 186 insertions(+), 1 deletion(-) create mode 100644 llvm/test/DebugInfo/missing-abstract-variable.ll diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp index fddc7fa..2325ab8 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp @@ -1781,7 +1781,11 @@ std::unique_ptr DwarfUnit::constructVariableDIEImpl(const DbgVariable &DV, // Define variable debug information entry. auto VariableDie = make_unique(DV.getTag()); - if (DbgVariable *AbsVar = DV.getAbstractVariable()) + DbgVariable *AbsVar = DV.getAbstractVariable(); + // FIXME: any missing abstract variable missing a DIE will result in incorrect + // DWARF. More details in test/DebugInfo/missing-abstract-variable.ll for an + // example of why this is happening. + if (AbsVar && AbsVar->getDIE()) addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin, *AbsVar->getDIE()); else { if (!Name.empty()) diff --git a/llvm/test/DebugInfo/missing-abstract-variable.ll b/llvm/test/DebugInfo/missing-abstract-variable.ll new file mode 100644 index 0000000..5718a5b --- /dev/null +++ b/llvm/test/DebugInfo/missing-abstract-variable.ll @@ -0,0 +1,181 @@ +; REQUIRES: object-emission + +; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s + +; Build from the following source with clang -O2. + +; The important details are that 'x's abstract definition is first built during +; the definition of 'b', where the parameter to 'x' is constant and so 'x's 's' +; variable is optimized away. No abstract definition DIE for 's' is constructed. +; Then, during 'a' emission, the abstract DbgVariable for 's' is created, but +; the abstract DIE isn't (since the abstract definition for 'b' is already +; built). This results in 's' inlined in 'a' being emitted with its name, line, +; file there, rather than referencing an abstract definition. + +; extern int t; +; +; void f(int); +; +; inline void x(bool b) { +; if (b) { +; int s = t; +; f(s); +; } +; f(0); +; } +; +; void b() { +; x(false); +; } +; +; void a(bool u) { +; x(u); +; } + +; CHECK: [[ABS_X:.*]]: DW_TAG_subprogram +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_name {{.*}} "x" +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: [[ABS_B:.*]]: DW_TAG_formal_parameter +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_name {{.*}} "b" +; FIXME: Missing 'x's local 's' variable. + +; CHECK: DW_TAG_subprogram +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_name {{.*}} "b" +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: DW_TAG_inlined_subroutine +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_X]]} +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: DW_TAG_formal_parameter +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_B]]} +; Notice 'x's local variable 's' is missing. Not necessarily a bug here, +; since it's been optimized entirely away and it should be described in +; abstract subprogram. +; CHECK-NOT: DW_TAG +; CHECK: NULL +; CHECK-NOT: DW_TAG +; CHECK: NULL + +; CHECK: DW_TAG_subprogram +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_name {{.*}} "a" +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: DW_TAG_formal_parameter +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: DW_TAG_inlined_subroutine +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_X]]} +; CHECK-NOT: {{DW_TAG|NULL}} +; FIXME: This formal parameter goes missing at least at -O2, maybe before that. +; CHECK: DW_TAG_formal_parameter +; CHECK-NOT: DW_TAG +; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_B]]} + +; The two lexical blocks here are caused by the scope of the if that includes +; the condition variable, and the scope within the if's composite statement. I'm +; not sure we really need both of them. + +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: DW_TAG_lexical_block +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: DW_TAG_lexical_block +; CHECK-NOT: {{DW_TAG|NULL}} +; CHECK: DW_TAG_variable +; CHECK-NOT: DW_TAG + +; FIXME: This shouldn't have a name here, it should use DW_AT_abstract_origin +; to reference an abstract variable definition instead + +; CHECK: DW_AT_name {{.*}} "s" + + +@t = external global i32 + +; Function Attrs: uwtable +define void @_Z1bv() #0 { +entry: + tail call void @llvm.dbg.value(metadata !24, i64 0, metadata !25), !dbg !27 + tail call void @_Z1fi(i32 0), !dbg !28 + ret void, !dbg !29 +} + +; Function Attrs: uwtable +define void @_Z1ab(i1 zeroext %u) #0 { +entry: + tail call void @llvm.dbg.value(metadata !{i1 %u}, i64 0, metadata !13), !dbg !30 + tail call void @llvm.dbg.value(metadata !{i1 %u}, i64 0, metadata !31), !dbg !33 + br i1 %u, label %if.then.i, label %_Z1xb.exit, !dbg !34 + +if.then.i: ; preds = %entry + %0 = load i32* @t, align 4, !dbg !35, !tbaa !36 + tail call void @llvm.dbg.value(metadata !{i32 %0}, i64 0, metadata !40), !dbg !35 + tail call void @_Z1fi(i32 %0), !dbg !41 + br label %_Z1xb.exit, !dbg !42 + +_Z1xb.exit: ; preds = %entry, %if.then.i + tail call void @_Z1fi(i32 0), !dbg !43 + ret void, !dbg !44 +} + +declare void @_Z1fi(i32) #1 + +; Function Attrs: nounwind readnone +declare void @llvm.dbg.value(metadata, i64, metadata) #2 + +attributes #0 = { uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } +attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } +attributes #2 = { nounwind readnone } + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!21, !22} +!llvm.ident = !{!23} + +!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.5.0 ", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [/tmp/dbginfo/missing-abstract-variables.cc] [DW_LANG_C_plus_plus] +!1 = metadata !{metadata !"missing-abstract-variables.cc", metadata !"/tmp/dbginfo"} +!2 = metadata !{} +!3 = metadata !{metadata !4, metadata !8, metadata !14} +!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"b", metadata !"b", metadata !"_Z1bv", i32 13, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void ()* @_Z1bv, null, null, metadata !2, i32 13} ; [ DW_TAG_subprogram ] [line 13] [def] [b] +!5 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type ] [/tmp/dbginfo/missing-abstract-variables.cc] +!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ] +!7 = metadata !{null} +!8 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"a", metadata !"a", metadata !"_Z1ab", i32 17, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void (i1)* @_Z1ab, null, null, metadata !12, i32 17} ; [ DW_TAG_subprogram ] [line 17] [def] [a] +!9 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !10, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ] +!10 = metadata !{null, metadata !11} +!11 = metadata !{i32 786468, null, null, metadata !"bool", i32 0, i64 8, i64 8, i64 0, i32 0, i32 2} ; [ DW_TAG_base_type ] [bool] [line 0, size 8, align 8, offset 0, enc DW_ATE_boolean] +!12 = metadata !{metadata !13} +!13 = metadata !{i32 786689, metadata !8, metadata !"u", metadata !5, i32 16777233, metadata !11, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [u] [line 17] +!14 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"x", metadata !"x", metadata !"_Z1xb", i32 5, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, null, null, null, metadata !15, i32 5} ; [ DW_TAG_subprogram ] [line 5] [def] [x] +!15 = metadata !{metadata !16, metadata !17} +!16 = metadata !{i32 786689, metadata !14, metadata !"b", metadata !5, i32 16777221, metadata !11, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [b] [line 5] +!17 = metadata !{i32 786688, metadata !18, metadata !"s", metadata !5, i32 7, metadata !20, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [s] [line 7] +!18 = metadata !{i32 786443, metadata !1, metadata !19, i32 6, i32 0, i32 0, i32 1} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/missing-abstract-variables.cc] +!19 = metadata !{i32 786443, metadata !1, metadata !14, i32 6, i32 0, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/missing-abstract-variables.cc] +!20 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed] +!21 = metadata !{i32 2, metadata !"Dwarf Version", i32 4} +!22 = metadata !{i32 2, metadata !"Debug Info Version", i32 1} +!23 = metadata !{metadata !"clang version 3.5.0 "} +!24 = metadata !{i1 false} +!25 = metadata !{i32 786689, metadata !14, metadata !"b", metadata !5, i32 16777221, metadata !11, i32 0, metadata !26} ; [ DW_TAG_arg_variable ] [b] [line 5] +!26 = metadata !{i32 14, i32 0, metadata !4, null} +!27 = metadata !{i32 5, i32 0, metadata !14, metadata !26} +!28 = metadata !{i32 10, i32 0, metadata !14, metadata !26} +!29 = metadata !{i32 15, i32 0, metadata !4, null} +!30 = metadata !{i32 17, i32 0, metadata !8, null} +!31 = metadata !{i32 786689, metadata !14, metadata !"b", metadata !5, i32 16777221, metadata !11, i32 0, metadata !32} ; [ DW_TAG_arg_variable ] [b] [line 5] +!32 = metadata !{i32 18, i32 0, metadata !8, null} +!33 = metadata !{i32 5, i32 0, metadata !14, metadata !32} +!34 = metadata !{i32 6, i32 0, metadata !19, metadata !32} +!35 = metadata !{i32 7, i32 0, metadata !18, metadata !32} +!36 = metadata !{metadata !37, metadata !37, i64 0} +!37 = metadata !{metadata !"int", metadata !38, i64 0} +!38 = metadata !{metadata !"omnipotent char", metadata !39, i64 0} +!39 = metadata !{metadata !"Simple C/C++ TBAA"} +!40 = metadata !{i32 786688, metadata !18, metadata !"s", metadata !5, i32 7, metadata !20, i32 0, metadata !32} ; [ DW_TAG_auto_variable ] [s] [line 7] +!41 = metadata !{i32 8, i32 0, metadata !18, metadata !32} ; [ DW_TAG_imported_declaration ] +!42 = metadata !{i32 9, i32 0, metadata !18, metadata !32} +!43 = metadata !{i32 10, i32 0, metadata !14, metadata !32} +!44 = metadata !{i32 19, i32 0, metadata !8, null} -- 2.7.4