PR15662: Optimized debug info produces out of order function parameters

When a function is inlined we lazily construct the variables
representing the function's parameters. After that, we add any remaining
unused parameters.

If the function doesn't use all the parameters, or uses them out of
order, then the DWARF would produce them in that order, producing a
parameter order that doesn't match the source.

This fix causes us to always keep the arg variables at the start of the
variable list & in the original order from the source.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183297 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 73 insertions, 0 deletions

diff --git a/test/DebugInfo/inlined-arguments.ll b/test/DebugInfo/inlined-arguments.ll
new file mode 100644
index 0000000..d3ece10
--- /dev/null
+++ b/test/DebugInfo/inlined-arguments.ll
@@ -0,0 +1,73 @@
+; RUN: llc -filetype=obj < %s > %t
+; RUN: llvm-dwarfdump %t | FileCheck %s
+
+; IR generated from clang -O -g with the following source
+;
+; void f1(int x, int y);
+; void f3(int line);
+; void f2() {
+;   f1(1, 2);
+; }
+; void f1(int x, int y) {
+;   f3(y);
+; }
+
+; CHECK: DW_AT_name{{.*}}"f1"
+; CHECK: DW_TAG_formal_parameter
+; CHECK-NEXT: DW_AT_name{{.*}}"x"
+; CHECK: DW_TAG_formal_parameter
+; CHECK-NEXT: DW_AT_name{{.*}}"y"
+
+; Function Attrs: uwtable
+define void @_Z2f2v() #0 {
+  tail call void @llvm.dbg.value(metadata !15, i64 0, metadata !16), !dbg !18
+  tail call void @llvm.dbg.value(metadata !19, i64 0, metadata !20), !dbg !18
+  tail call void @_Z2f3i(i32 2), !dbg !21
+  ret void, !dbg !22
+}
+
+; Function Attrs: uwtable
+define void @_Z2f1ii(i32 %x, i32 %y) #0 {
+  tail call void @llvm.dbg.value(metadata !{i32 %x}, i64 0, metadata !13), !dbg !23
+  tail call void @llvm.dbg.value(metadata !{i32 %y}, i64 0, metadata !14), !dbg !23
+  tail call void @_Z2f3i(i32 %y), !dbg !24
+  ret void, !dbg !25
+}
+
+declare void @_Z2f3i(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-frame-pointer-elim-non-leaf"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+
+!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.4 ", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [/usr/local/google/home/blaikie/dev/scratch/exp.cpp] [DW_LANG_C_plus_plus]
+!1 = metadata !{metadata !"exp.cpp", metadata !"/usr/local/google/home/blaikie/dev/scratch"}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4, metadata !8}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"f2", metadata !"f2", metadata !"_Z2f2v", i32 3, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void ()* @_Z2f2v, null, null, metadata !2, i32 3} ; [ DW_TAG_subprogram ] [line 3] [def] [f2]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [/usr/local/google/home/blaikie/dev/scratch/exp.cpp]
+!6 = metadata !{i32 786453, i32 0, i32 0, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, i32 0} ; [ 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 !"f1", metadata !"f1", metadata !"_Z2f1ii", i32 6, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void (i32, i32)* @_Z2f1ii, null, null, metadata !12, i32 6} ; [ DW_TAG_subprogram ] [line 6] [def] [f1]
+!9 = metadata !{i32 786453, i32 0, i32 0, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !10, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!10 = metadata !{null, metadata !11, metadata !11}
+!11 = 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]
+!12 = metadata !{metadata !13, metadata !14}
+!13 = metadata !{i32 786689, metadata !8, metadata !"x", metadata !5, i32 16777222, metadata !11, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [x] [line 6]
+!14 = metadata !{i32 786689, metadata !8, metadata !"y", metadata !5, i32 33554438, metadata !11, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [y] [line 6]
+!15 = metadata !{i32 undef}
+!16 = metadata !{i32 786689, metadata !8, metadata !"x", metadata !5, i32 16777222, metadata !11, i32 0, metadata !17} ; [ DW_TAG_arg_variable ] [x] [line 6]
+!17 = metadata !{i32 4, i32 0, metadata !4, null}
+!18 = metadata !{i32 6, i32 0, metadata !8, metadata !17}
+!19 = metadata !{i32 2}
+!20 = metadata !{i32 786689, metadata !8, metadata !"y", metadata !5, i32 33554438, metadata !11, i32 0, metadata !17} ; [ DW_TAG_arg_variable ] [y] [line 6]
+!21 = metadata !{i32 7, i32 0, metadata !8, metadata !17}
+!22 = metadata !{i32 5, i32 0, metadata !4, null}
+!23 = metadata !{i32 6, i32 0, metadata !8, null}
+!24 = metadata !{i32 7, i32 0, metadata !8, null}
+!25 = metadata !{i32 8, i32 0, metadata !8, null} ; [ DW_TAG_imported_declaration ]