Don't emit anything into the debug_ranges section if we aren't emitting

any ranges - this includes CU ranges where we were previously emitting an
end list marker even if we didn't have a list.

Testcase includes a test for line table only code emission as the problem
was noticed while writing this test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202357 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index ca060e2cc220e824e42030d05242222d307adb7f..2eff17176b8a24753c4508d7bc3bc1bc47f88904 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2873,7 +2873,7 @@ void DwarfDebug::emitDebugRanges() {
     }
 
     // Now emit a range for the CU itself.
-    if (useCURanges()) {
+    if (useCURanges() && TheCU->getRanges().size()) {
       Asm->OutStreamer.EmitLabel(
           Asm->GetTempSymbol("cu_ranges", TheCU->getUniqueID()));
       const SmallVectorImpl<RangeSpan> &Ranges = TheCU->getRanges();

diff --git a/test/DebugInfo/cu-line-tables.ll b/test/DebugInfo/cu-line-tables.ll
new file mode 100644 (file)
index 0000000..493184d
--- /dev/null
+++ b/test/DebugInfo/cu-line-tables.ll
@@ -0,0 +1,50 @@
+; REQUIRES: object-emission
+; RUN: %llc_dwarf -O0 -filetype=obj -generate-dwarf-cu-ranges %s -o %t
+; RUN: llvm-dwarfdump %t | FileCheck %s
+
+; Check that we don't emit ranges even if the option is passed if we're emitting line tables only.
+
+; CHECK: DW_TAG_compile_unit
+; CHECK-NOT: DW_AT_ranges
+; CHECK: DW_TAG_subprogram
+
+; FIXME: We probably want to avoid printing out anything if the section isn't there.
+; CHECK: .debug_ranges contents:
+; CHECK-NOT: 00000000 <End of list>
+
+; Function Attrs: nounwind uwtable
+define i32 @f(i32 %a) #0 {
+entry:
+  %a.addr = alloca i32, align 4
+  store i32 %a, i32* %a.addr, align 4
+  call void @llvm.dbg.declare(metadata !{i32* %a.addr}, metadata !12), !dbg !13
+  %0 = load i32* %a.addr, align 4, !dbg !14
+  %add = add nsw i32 %0, 4, !dbg !14
+  ret i32 %add, !dbg !14
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata) #1
+
+attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "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 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!9, !10}
+!llvm.ident = !{!11}
+
+!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5 (trunk 197756) (llvm/trunk 197768)", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 2} ; [ DW_TAG_compile_unit ] [/usr/local/google/home/echristo/tmp/foo.c] [DW_LANG_C99]
+!1 = metadata !{metadata !"foo.c", metadata !"/usr/local/google/home/echristo/tmp"}
+!2 = metadata !{}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"f", metadata !"f", metadata !"", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 (i32)* @f, null, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [f]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [/usr/local/google/home/echristo/tmp/foo.c]
+!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 !{metadata !8, metadata !8}
+!8 = 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]
+!9 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
+!10 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
+!11 = metadata !{metadata !"clang version 3.5 (trunk 197756) (llvm/trunk 197768)"}
+!12 = metadata !{i32 786689, metadata !4, metadata !"a", metadata !5, i32 16777217, metadata !8, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [a] [line 1]
+!13 = metadata !{i32 1, i32 0, metadata !4, null}
+!14 = metadata !{i32 2, i32 0, metadata !4, null}