[llvm] r202357 - Don't emit anything into the debug_ranges section if we aren't emitting

[Eric Christopher]

Author: echristo
Date: Thu Feb 27 01:44:45 2014
New Revision: 202357

URL: http://llvm.org/viewvc/llvm-project?rev=202357&view=rev
Log:
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.

Added:
    llvm/trunk/test/DebugInfo/cu-line-tables.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=202357&r1=202356&r2=202357&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Thu Feb 27 01:44:45 2014
@@ -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();

Added: llvm/trunk/test/DebugInfo/cu-line-tables.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/cu-line-tables.ll?rev=202357&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/cu-line-tables.ll (added)
+++ llvm/trunk/test/DebugInfo/cu-line-tables.ll Thu Feb 27 01:44:45 2014
@@ -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}