If we see that we're emitting code for a function that doesn't have

any lexical scopes then go ahead and turn on DW_AT_ranges for the
compile unit since we would be claiming to describe in the CU
a range for which we don't have information in the CU otherwise.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203969 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index ed5bcf3c7bd10f438b2a3b2fdde1e3471b955b88..fa966d01c9d95dd815b9fa1052b4b2874daa4c12 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1462,8 +1462,10 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) {
   // Grab the lexical scopes for the function, if we don't have any of those
   // then we're not going to be able to do anything.
   LScopes.initialize(*MF);
-  if (LScopes.empty())
+  if (LScopes.empty()) {
+    UsedNonDefaultText = true;
     return;
+  }
 
   assert(UserVariables.empty() && DbgValues.empty() && "Maps weren't cleaned");
 

diff --git a/test/DebugInfo/cu-range-hole.ll b/test/DebugInfo/cu-range-hole.ll
new file mode 100644 (file)
index 0000000..46d2083
--- /dev/null
+++ b/test/DebugInfo/cu-range-hole.ll
@@ -0,0 +1,56 @@
+; REQUIRES: object-emission
+; RUN: %llc_dwarf -O0 -filetype=obj %s -o %t
+; RUN: llvm-dwarfdump %t | FileCheck %s
+
+; Check that we emit ranges for this CU since we have a function with and
+; without debug info.
+; CHECK: DW_TAG_compile_unit
+; CHECK: DW_AT_ranges
+; CHECK: DW_TAG_subprogram
+
+; Function Attrs: nounwind uwtable
+define i32 @foo(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, 5, !dbg !14
+  ret i32 %add, !dbg !14
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata) #1
+
+; Function Attrs: nounwind uwtable
+define i32 @bar(i32 %b) #0 {
+entry:
+  %b.addr = alloca i32, align 4
+  store i32 %b, i32* %b.addr, align 4
+  %0 = load i32* %b.addr, align 4
+  %add = add nsw i32 %0, 1
+  ret i32 %add
+}
+
+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, !11}
+
+!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5.0 (trunk 203945) (llvm/trunk 203946)", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 1}
+!1 = metadata !{metadata !"foo.c", metadata !"/usr/local/google/home/echristo"}
+!2 = metadata !{}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"foo", metadata !"foo", metadata !"", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 (i32)* @foo, null, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [/usr/local/google/home/echristo/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 3.5.0 (trunk 203945) (llvm/trunk 203946)"}
+!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}